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WO2018179607A1 - Projection optical system, image projection device, and image projection system - Google Patents

Projection optical system, image projection device, and image projection system Download PDF

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Publication number
WO2018179607A1
WO2018179607A1 PCT/JP2017/044305 JP2017044305W WO2018179607A1 WO 2018179607 A1 WO2018179607 A1 WO 2018179607A1 JP 2017044305 W JP2017044305 W JP 2017044305W WO 2018179607 A1 WO2018179607 A1 WO 2018179607A1
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WO
WIPO (PCT)
Prior art keywords
optical system
projection
lens
projection optical
lenses
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PCT/JP2017/044305
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French (fr)
Japanese (ja)
Inventor
恒夫 内田
克 山田
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パナソニックＩｐマネジメント株式会社
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Publication of WO2018179607A1 publication Critical patent/WO2018179607A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/16—Optical objectives specially designed for the purposes specified below for use in conjunction with image converters or intensifiers, or for use with projectors, e.g. objectives for projection TV
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/08—Catadioptric systems

Definitions

  • the present disclosure relates to a projection optical system for projecting an image generated by an image display element.
  • Patent Document 1 discloses a projection apparatus using a projection optical system including a reflecting surface.
  • the projection optical system is a projection optical system for enlarging and projecting an image formed on the light valve onto a projection surface, and includes a lens optical system, a first reflection surface, and a second reflection surface.
  • the lens optical system includes a plurality of lenses, and has a positive power for forming an intermediate image of an image between the projection surface and the light valve.
  • the first reflecting surface reflects the divergent light beam after forming the intermediate image and has a positive power to form an image on the projection surface.
  • the second reflecting surface causes the light emitted from the lens optical system to enter the first reflecting surface. As a result, a large screen with reduced chromatic aberration and distortion can be projected.
  • the present disclosure provides a projection optical system that can reduce image distortion while being small in size.
  • a projection optical system is a projection optical system that is used for projecting an image on a projection surface and has a conjugate relationship between a reduction-side image plane and a projection-side image plane.
  • An optical system and a reflective optical system are provided.
  • the transmission optical system includes an aperture stop and a plurality of lenses each having power.
  • the reflection optical system reflects the light emitted from the transmission optical system.
  • the principal ray of the reference ray is a ray that passes through the center of the aperture stop among the rays that are projected closest to the projection optical system on the projection surface.
  • the projection optical system has an intermediate image plane conjugate with the reduction-side image plane between the transmission optical system and the reflection optical system, and satisfies the following conditional expression (1).
  • Tl is the distance from the most reduced lens among the plurality of lenses to the lens closest to the projection surface among the plurality of lenses.
  • Pex is the maximum distance among the optical path lengths of the principal rays of the reference rays from the exit pupil position of the transmission optical system with reference to the principal ray of the reference rays to the lens closest to the projection surface among the plurality of lenses. .
  • An image projection apparatus includes the above-described projection optical system and an image forming element that forms an image and has an image display surface as a reduction-side image surface.
  • the image projection device can be reduced in size and image distortion can be reduced.
  • FIG. 1 is a diagram illustrating an image projection system according to the present disclosure.
  • FIG. 2 is a configuration diagram illustrating an image projection apparatus according to the present disclosure.
  • FIG. 3 is a configuration diagram of a transmission optical system in Numerical Example 1.
  • FIG. 4 is a configuration diagram of a transmission optical system in Numerical Example 2.
  • FIG. 5 is a configuration diagram of a transmission optical system in Numerical Example 3.
  • FIG. 6 is a configuration diagram of a transmission optical system in Numerical Example 4.
  • FIG. 7 is a configuration diagram of a transmission optical system in Numerical Example 5.
  • FIG. 1 is a diagram illustrating an image projection system 1 according to the present disclosure.
  • the image projection system 1 includes an image projection device 10 and a screen SC (an example of a projection surface).
  • the image projection apparatus 10 includes a projection optical system 100, an image display element 130, and a transmission element 140.
  • the projection optical system 100 includes a transmission optical system 110 and a reflection optical system 120.
  • the image projection device 10 projects the image formed by the image display element 130 onto the screen SC in a direction (diagonal direction) that does not face the image.
  • the direction in which the screen SC does not face is that the direction of the normal line at the point on the screen SC where the reference ray R reaches and the principal ray optical path of the reference ray R emitted from the final surface of the projection optical system 100. Say when the direction does not match.
  • a straight line connecting the rotationally symmetric axes of the lens elements arranged on the enlargement side is defined as an optical axis AZ.
  • the optical axis AZ may be an axis that shares the most lens centers.
  • the optical axis AZ may be set at a position eccentric with respect to the image display element 130 in a plane including the optical path of the emitted light.
  • the optical path of the emitted light means the optical path of the principal ray from the center of the image display element 130 to the center of the enlarged image on the screen SC in the optical path from the image display element 130 to the screen SC.
  • the reduction side means the image display element 130 side in the projection optical system 100.
  • the enlargement side means the screen SC side in the projection optical system 100.
  • the principal ray of the reference ray R is a ray that passes through the center of the aperture stop A among the rays that are projected closest to the projection optical system 100 of the screen SC.
  • the optical axis AZ is an extension of the optical axis of the optical system after being reflected and bent by the reflecting surface. It may be set as a line.
  • the image projection apparatus 10 projects an image on a screen SC having a curvature.
  • FIG. 2 is a configuration diagram illustrating the image projection device 10 of the present disclosure.
  • the projection optical system 100 includes a transmission optical system 110 having a positive power as a whole and a reflection optical system 120 having a positive power as a whole.
  • the principal ray of the reference ray R passing through the center of the aperture stop A does not intersect the optical axis AZ between the image plane on the reduction side and the aperture stop A.
  • the transmission optical system 110 includes a first lens group G1 having positive power, a second lens group G2 having positive power, a third lens group G3 having positive power, and a fourth lens having positive power. It consists of a group G4 and a prism PB.
  • the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 are arranged in order from the image display element 130 to the screen SC.
  • the prism PB is disposed between the image display element 130 and the first lens group G1. In the present disclosure, the prism PB has no power. Therefore, for example, in the transmission optical system 110 of FIG. 3, the plurality of lenses having power means the lens elements L1 to L14.
  • the first lens group G1 includes a first lens element L1 that is a single biconvex lens having a rotationally symmetric axis.
  • the first lens element L1 has an aspheric shape.
  • the second lens group G2 includes a second lens element L2, a third lens element L3, a fourth lens element L4, and a fifth lens element L5.
  • the second lens element L2 has a rotationally symmetric axis and has a negative meniscus shape.
  • the convex surface of the second lens element L2 faces the reduction side.
  • the third lens element L3 has a rotationally symmetric axis and has a biconvex shape.
  • the fourth lens element L4 has a rotationally symmetric axis and has a biconcave shape.
  • the fifth lens element L5 has a rotationally symmetric axis and has a biconvex shape.
  • the second lens element L2, the third lens element L3, and the fourth lens element L4 are cemented with each other.
  • the third lens group G3 includes an aperture stop A and has a positive power as a whole.
  • the third lens group G3 includes a sixth lens element L6, a seventh lens element L7, an eighth lens element L8, a ninth lens element L9, and a tenth lens element L10.
  • the sixth lens element L6 is disposed on the enlargement side with respect to the aperture stop A, has a rotationally symmetric axis, and has a positive meniscus shape.
  • the convex surface of the sixth lens element L6 faces the enlargement side.
  • the seventh lens element L7 (negative meniscus lens) has a rotationally symmetric axis and has a negative meniscus shape.
  • the convex surface of the seventh lens element L7 faces the enlargement side.
  • the eighth lens element L8 has a rotationally symmetric axis and has a positive meniscus shape.
  • the convex surface of the eighth lens element L8 faces the reduction side.
  • the ninth lens element L9 has a rotationally symmetric axis and has a biconvex shape.
  • the tenth lens element L10 has a rotationally symmetric axis and has a negative meniscus shape.
  • the convex surface of the tenth lens element L10 faces the enlargement side.
  • the fourth lens group G4 is arranged closest to the screen SC among the lens groups of the transmission optical system 110.
  • the fourth lens group G4 includes an eleventh lens element L11, a twelfth lens element L12, a thirteenth lens element L13, and a fourteenth lens element L14.
  • the eleventh lens element L11, the twelfth lens element L12, the thirteenth lens element L13, and the fourteenth lens element L14 are arranged in order from the image display element 130 to the screen SC.
  • the eleventh lens element L11 has a rotationally symmetric axis and has positive power.
  • the convex surface of the eleventh lens element L11 faces the reduction side.
  • the twelfth lens element L12 has a rotationally symmetric axis and has negative power.
  • the concave surface of the twelfth lens element L12 faces the enlargement side.
  • the thirteenth lens element L13 has a rotationally symmetric axis and has a biconcave shape.
  • the fourteenth lens element L14 has a rotationally symmetric axis and has a positive meniscus shape.
  • the convex surface of the fourteenth lens element L14 faces the enlargement side.
  • the eleventh lens element L11 and the twelfth lens element L12 are cemented with each other.
  • the thirteenth lens element L13 and the fourteenth lens element L14 are lens elements having an aspherical shape.
  • the third lens group G3 includes an aperture stop A and has a positive power as a whole.
  • the third lens group G3 includes a sixth lens element L6, a seventh lens element L7, an eighth lens element L8, a ninth lens element L9, and a tenth lens element L10.
  • the sixth lens element L6 is disposed on the enlargement side with respect to the aperture stop A, has a rotationally symmetric axis, and has a positive meniscus shape.
  • the convex surface of the sixth lens element L6 faces the enlargement side.
  • the seventh lens element L7 (negative meniscus lens) has a rotationally symmetric axis and has a negative meniscus shape.
  • the convex surface of the seventh lens element L7 faces the enlargement side.
  • the eighth lens element L8 has a rotationally symmetric axis and has positive power.
  • the convex surface of the eighth lens element L8 faces the reduction side.
  • the ninth lens element L9 has a rotationally symmetric axis and has a biconcave shape.
  • the tenth lens element L10 has a rotationally symmetric axis and has a biconvex shape.
  • the ninth lens element L9 and the tenth lens element L10 are cemented with each other.
  • the fourth lens group G4 is disposed closest to the screen SC in the transmission optical system 110.
  • the fourth lens group G4 includes an eleventh lens element L11, a twelfth lens element L12, and a thirteenth lens element L13.
  • the eleventh lens element L11, the twelfth lens element L12, and the thirteenth lens element L13 are arranged in order from the image display element 130 to the screen SC.
  • the eleventh lens element L11 has a rotationally symmetric axis and has a positive meniscus shape.
  • the convex surface of the eleventh lens element L11 faces the reduction side.
  • the twelfth lens element L12 has a rotationally symmetric axis and has a biconcave shape.
  • the thirteenth lens element L13 has a rotationally symmetric axis and has a positive meniscus shape.
  • the convex surface of the thirteenth lens element L13 faces the enlargement side.
  • the twelfth lens element L12 and the thirteenth lens element L13 are lens elements having an aspherical shape.
  • the lens adjacent to the image display element 130 side of the most projected side lens or a part of the lens elements constituting the fourth lens group G4 has a biconcave shape. It is desirable that at least one surface of the biconcave lens has an aspherical shape. Specifically, this aspherical shape is a shape in which the curvature decreases with increasing distance from the center of the lens in the radial direction. That is, this aspherical shape is a shape in which the power on the outer side of the lens is smaller than that on the lens center side.
  • the third lens element L3 (positive lens) may have the strongest positive power among the lens elements.
  • the fourth lens element L4 (negative lens) may have the strongest negative power among the lens elements. 3 to 7, the third lens element L3 and the fourth lens element L4 are joined, but they may be arranged adjacent to each other without being joined.
  • the projection optical system 100 is focused by two lens groups, the second lens group G2 and the fourth lens group G4.
  • the fourth lens group G4 includes at least one aspheric surface, and suppresses image distortion and resolution degradation that occur during focusing. Thereby, good optical performance can be satisfied even if the projection distance changes.
  • the projection optical system 100 uses a part of the lens elements or a plurality of lens elements on the enlargement side of the aperture stop A as a focus group, thereby suppressing image distortion and resolution degradation that occur during focusing. It is also possible. Thereby, good optical performance can be satisfied even if the projection distance changes.
  • the concave surface of the positive meniscus-shaped maximum magnification side lens and the concave surface on the expansion side of the negative meniscus lens or the negative lens element joined to the positive lens element face each other. Yes.
  • the fourth lens group G4 has the most projection side lens on the most screen SC side.
  • the most projection side lens has a shape with the largest thickness deviation ratio in the transmission optical system 110. As a result, the difference in refractive power between the center and the periphery of the transmitted light beam can be increased, which is effective in correcting field curvature.
  • an effect can be expected to reduce the height of the transmission optical system 110.
  • a part of the lens elements away from the aperture stop A such as a lens element arranged on the reduction side and a lens element arranged on the enlargement side, a further reduction in height can be expected. Note that the cut lens element does not have a rotationally symmetric axis.
  • An intermediate image plane I (see FIG. 2) is formed between the transmission optical system 110 and the screen SC. This makes it possible to employ a concave mirror as a part of the reflective optical system 120, which is advantageous for enlarging the projection area and reducing the size of the reflective optical system 120. Further, the intermediate image plane I formed by the transmission optical system 110 has a characteristic that an image point formed by a light ray closest to the optical axis AZ is formed at a position farthest from the transmission optical system 110. The intermediate image plane I is preferably formed at a position that does not straddle the reflection surface of the reflection optical system 120.
  • the reflection optical system 120 reflects the light beam emitted from the transmission optical system 110 and projects the reflected light beam onto the screen SC.
  • the reflective optical system 120 includes two mirrors, a first mirror 121 (an example of a concave mirror) and a second mirror 122 (an example of a plane mirror).
  • the reflecting surface of the first mirror 121 has a concave free-form surface.
  • the first mirror 121 has a positive power as a whole.
  • the reflection optical system 120 only needs to be composed of one or more mirrors, and is not limited to being composed of two mirrors.
  • the image display element 130 forms an image to be projected on the screen SC based on the image signal.
  • a spatial modulation element such as a DMD (Digital Micromirror Device) or a transmissive or reflective liquid crystal panel can be used.
  • the image display element 130 according to the present disclosure is a rectangle having a long side in the X-axis direction (perpendicular to the paper surface) in FIG. 2 and a short side in the Y-axis direction.
  • the transmissive element 140 is disposed between the reflective optical system 120 and the screen SC.
  • the light beam reflected by the reflective optical system 120 is transmitted through the transmissive element 140 and projected onto the screen SC.
  • the shape of the transmissive element 140 is a toroidal shape having different curvatures in a direction corresponding to the long side direction of the image display element 130 and a direction corresponding to the short side direction.
  • the convex surface of the transmissive element 140 faces the screen SC side. That is, the curvature in the X-axis direction (perpendicular to the paper surface in FIG. 2) corresponding to the long side direction of the image display element 130 on the incident surface of the transmission element 140 is larger than the curvature in the Y-axis direction corresponding to the short side direction.
  • the first mirror 121 on the image display element 130 side preferably has a free-form surface shape. Since the first mirror 121 has a free-form surface having a positive power, it is possible to suppress the height of light incident on the second mirror 122 while correcting image distortion. Therefore, it is advantageous for downsizing.
  • a projection optical system 100 is a projection optical system that is used for projecting an image on a screen SC and has a conjugate relationship between a reduction-side image plane and a screen SC-side image plane.
  • a transmission optical system 110 and a reflection optical system 120 are provided.
  • the transmission optical system 110 includes an aperture stop A and a plurality of lenses each having power.
  • the reflection optical system 120 reflects light emitted from the transmission optical system 110.
  • the principal ray of the reference ray R is a ray that passes through the center of the aperture stop A among the rays that are projected closest to the projection optical system 100 of the screen SC.
  • the projection optical system 100 has an intermediate image plane I conjugate with the reduction-side image plane between the transmission optical system 110 and the reflection optical system 120.
  • this configuration is referred to as a basic configuration of the embodiment.
  • the projection optical system 100 preferably satisfies the following conditional expression (1).
  • Tl is the distance from the most reduction side lens to the most screen SC side lens.
  • is the maximum distance in the optical path length of the principal ray of the reference ray R from the exit pupil position of the transmission optical system 110 with respect to the principal ray of the reference ray R to the lens closest to the screen SC.
  • Conditional expression (1) defines a preferable range between the exit pupil position and the total length with the principal ray of the reference ray R of the transmission optical system 110 as a reference (the optical axis of the ray).
  • the reference light beam R is a light beam projected by the image projection apparatus 10 including the projection optical system 100 to the foremost side of the screen SC.
  • the projection optical system 100 preferably satisfies the following conditional expression (2).
  • Conditional expression (2) defines a preferable range of the entrance pupil position and the total length with the principal ray of the reference ray R of the transmission optical system 110 as a reference (the optical axis of the ray).
  • / Tl falls below the lower limit of the conditional expression (2), the angle of light incident from the image plane increases, and the light loss when the DMD is used as the display element becomes significant. Therefore, it becomes difficult to maintain the illuminance distribution uniformity on the screen SC.
  • / Tl exceeds the upper limit of the conditional expression (2), the total length of the transmission optical system 110 with respect to the projection optical system 100 becomes short, and it becomes difficult to maintain the field curvature well.
  • the projection optical system 100 preferably satisfies the following conditional expression (3).
  • Rf is the maximum focal length of the transmission optical system 110 based on the principal ray of the reference ray R.
  • Conditional expression (3) defines a preferable range between the focal length of the transmission optical system 110 and the total length with the principal ray of the reference ray R as a reference (the optical axis of the ray).
  • Tl / Rf falls below the lower limit of the conditional expression (3), the total length of the transmission optical system 110 becomes short, and it becomes difficult to maintain sufficient optical performance as the projection optical system 100.
  • the intermediate image plane I of the transmission optical system 110 is formed at a position away from the transmission optical system 110, the reflection optical system 120 becomes large, which is disadvantageous for downsizing the projection optical system 100.
  • Tl / Rf exceeds the upper limit of the conditional expression (3), the total length of the transmission optical system 110 is increased, which is disadvantageous for downsizing of the projection optical system 100.
  • the projection optical system 100 preferably satisfies the following conditional expression (4).
  • Conditional expression (4) defines a suitable range of the exit pupil position and the total length with reference to the optical axis AZ of the transmission optical system 110.
  • / Tl satisfies the conditional expression (4), it is possible to obtain a projection optical system 100 that is small in size and reduced in image distortion.
  • / Tl exceeds the upper limit of the conditional expression (4), the projection optical system 100 has a configuration close to a telecentric optical system. However, if the curvature of field is appropriately corrected, the size of the transmission optical system 110 increases, which is disadvantageous for downsizing the projection optical system 100.
  • the projection optical system 100 preferably satisfies the following conditional expression (5).
  • Conditional expression (5) defines a suitable range of the entrance pupil position and the total length with reference to the optical axis AZ of the transmission optical system 110.
  • / Tl is less than the lower limit of the conditional expression (5), the angle of light incident from the image plane becomes large, and the light amount loss becomes significant when DMD is used as a display element. Therefore, it becomes difficult to maintain the illuminance distribution uniformity on the screen SC.
  • / Tl exceeds the upper limit of the conditional expression (5), the total length of the transmission optical system 110 with respect to the projection optical system 100 becomes short, and it becomes difficult to maintain the field curvature well.
  • Tables 1 to 5 show corresponding values of the conditional expressions obtained for the projection optical systems according to Numerical Examples 1 to 5. As shown in each table, for
  • the unit of length in the data is “mm”, and the unit of angle of view is “°”.
  • r is a radius of curvature
  • d is a surface interval
  • nd is a refractive index with respect to the d line
  • vd is an Abbe number with respect to the d line.
  • the surface marked with * is an aspherical surface or a free-form surface, and the aspherical shape is defined by the following equation.
  • z sag amount of the plane parallel to the z-axis
  • c curvature at the surface vertex
  • k conic coefficient
  • the lens constituent length is the distance from the first surface to the end surface
  • the front principal point position is the distance from the first surface
  • the rear principal point position is from the first surface. Is the distance.
  • 80 inches means a wide angle
  • 100 inches means a middle
  • 50 inches means telephoto.
  • FIG. 3 is a configuration diagram of the transmission optical system 110 in Numerical Example 1.
  • FIG. 4 is a configuration diagram of the transmission optical system 110 in Numerical Example 2.
  • FIG. 5 is a configuration diagram of the transmission optical system 110 in Numerical Example 3.
  • FIG. 6 is a configuration diagram of the transmission optical system 110 in Numerical Example 4.
  • FIG. 7 is a configuration diagram of the transmission optical system 110 in Numerical Example 5.
  • Tables 6 to 11 below show specific data of the transmission optical system 110 of Numerical Example 1.
  • the slow ratio in Numerical Example 1 is 0.175.
  • the projection magnification is 112.75 to 217.06.
  • the size of the image display element 130 to be used is 9.856 mm in the long side direction and 6.162 mm in the short side direction.
  • the image display element 130 is shifted in the +1.23 mm Y direction with respect to the R1 surface apex of the first lens element L1.
  • the zoom data is shown in Table 8 below.
  • the zoom ratio is 0.94855.
  • the single lens data is shown in Table 9 below.
  • the lens group data is shown in Table 10 below.
  • the zoom lens group magnification is shown in Table 11 below.
  • Tables 12 to 17 below show specific data of the transmission optical system 110 of Numerical Example 2.
  • the slow ratio in Numerical Example 2 is 0.177.
  • the projection magnification is 112.76 to 217.11.
  • the size of the image display element 130 to be used is 9.856 mm in the long side direction and 6.162 mm in the short side direction.
  • the image display element 130 is shifted in the +1.23 mm Y direction with respect to the R1 surface apex of the first lens element L1.
  • Table 12 below shows surface data of each optical element in Numerical Example 2.
  • the zoom data is shown in Table 14 below.
  • the zoom ratio is 0.92143.
  • the lens group data is shown in Table 16 below.
  • the zoom lens group magnification is shown in Table 17 below.
  • the zoom data is shown in Table 20 below.
  • the zoom ratio is 0.99414.
  • the lens group data is shown in Table 22 below.
  • zoom lens group magnifications are shown in Table 23.
  • Tables 24 to 29 below show specific data of the transmission optical system 110 according to Numerical Example 4.
  • the slow ratio in Numerical Example 4 is 0.194.
  • the projection magnification is 112.92 to 216.97 times.
  • the size of the image display element 130 to be used is 9.856 mm in the long side direction and 6.162 mm in the short side direction.
  • the image display element 130 is shifted in the +0.74 mm Y direction with respect to the R1 surface apex of the first lens element L1.
  • Table 25 shows the aspheric data.
  • the zoom data is shown in Table 26 below.
  • the zoom ratio is 1.003324.
  • Table 27 shows single lens data.
  • the lens group data is shown in Table 28 below.
  • zoom lens group magnifications are shown in Table 29.
  • Tables 30 to 35 below show specific data of the transmission optical system 110 of Numerical Example 5.
  • the slow ratio in Numerical Example 5 is 0.164.
  • the projection magnification is 112.85 to 217.06 times.
  • the size of the image display element 130 to be used is 9.856 mm in the long side direction and 6.162 mm in the short side direction.
  • the image display element 130 is shifted in the +1.24 mm Y direction with respect to the R1 surface apex of the first lens element L1.
  • Table 30 below shows surface data of each optical element in Numerical Example 5.
  • the zoom data is shown in Table 32 below.
  • the zoom ratio is 0.99046.
  • the lens group data is shown in Table 34 below.
  • zoom lens group magnifications are shown in Table 35.
  • the present disclosure can be applied to a projection optical system for projecting an image displayed on an image display element.
  • the present disclosure is applicable to a projector, a head-up display, and the like.

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Abstract

This projection optical system (100) is a projection optical system, which is used to project an image onto a projected surface (SC) and establishes a conjugate relationship between an image plane on a reduction side and an image plane on a projected surface (SC) side, the projection optical system (100) being provided with a transmissive optical system (110) and a reflective optical system (120). The transmissive optical system (110) includes an aperture diaphragm and a plurality of lenses each having power. The reflective optical system (120) reflects a beam emitted from the transmissive optical system (110). A main beam in a reference beam is the beam that passes through the center of the aperture diaphragm among beams projected onto the portion which, on the projected surface (SC), is closest to the transmissive optical system (100). The projection optical system (100) has an intermediate image plane, which has a conjugate relationship with the image plane of the reduction side, between the transmissive optical system (110) and the reflective optical system (120), and satisfies 0.70<|Pex|/Tl<40.

Description

投写光学系、画像投写装置および画像投写システムProjection optical system, image projection apparatus, and image projection system
　本開示は、画像表示素子が生成した画像を投写するための投写光学系に関する。 The present disclosure relates to a projection optical system for projecting an image generated by an image display element.
　特許文献１は、反射面を含む投写光学系を用いた投写装置を開示する。この投写光学系は、ライトバルブに形成された画像を投影面に拡大投影するための投写光学系であって、レンズ光学系と、第１反射面と、第２反射面と、からなる。レンズ光学系は、複数のレンズからなり、投影面とライトバルブとの間に、画像の中間像を形成するために正のパワーを有する。第１反射面は、中間像を結像した後の発散する光束を反射し、投影面上に結像させるために正のパワーを有する。第２反射面は、レンズ光学系からの射出光を第１反射面に入射させる。これにより、色収差および歪みが低減された大画面を投写することができる。 Patent Document 1 discloses a projection apparatus using a projection optical system including a reflecting surface. The projection optical system is a projection optical system for enlarging and projecting an image formed on the light valve onto a projection surface, and includes a lens optical system, a first reflection surface, and a second reflection surface. The lens optical system includes a plurality of lenses, and has a positive power for forming an intermediate image of an image between the projection surface and the light valve. The first reflecting surface reflects the divergent light beam after forming the intermediate image and has a positive power to form an image on the projection surface. The second reflecting surface causes the light emitted from the lens optical system to enter the first reflecting surface. As a result, a large screen with reduced chromatic aberration and distortion can be projected.
　しかしながら、特許文献１に記載された投写装置では、第１反射面から第２反射面までの距離が大きい。そのため、投写装置の大型化（高背化）を招いている。 However, in the projection apparatus described in Patent Document 1, the distance from the first reflecting surface to the second reflecting surface is large. For this reason, an increase in the size (height) of the projection apparatus is incurred.
特開２０１３－１７４８８６号公報JP 2013-174886 A
　本開示は、小型でありながら画像歪みを低減することができる投写光学系を提供する。 The present disclosure provides a projection optical system that can reduce image distortion while being small in size.
　本開示に係る投写光学系は、被投写面に画像を投写するために用いられ、縮小側の像面と被投写面側の像面とを共役の関係にする投写光学系であって、透過光学系と、反射光学系とを備える。透過光学系は、開口絞りと、それぞれパワーを有する複数のレンズとを含む。反射光学系は、透過光学系からの射出光を反射する。基準光線の主光線は、被投写面の最も投写光学系側に投写される光線のうち開口絞りの中心を通る光線である。投写光学系は、縮小側の像面と共役な中間像面を透過光学系と反射光学系の間に有し、以下の条件式（１）を満足する。 A projection optical system according to the present disclosure is a projection optical system that is used for projecting an image on a projection surface and has a conjugate relationship between a reduction-side image plane and a projection-side image plane. An optical system and a reflective optical system are provided. The transmission optical system includes an aperture stop and a plurality of lenses each having power. The reflection optical system reflects the light emitted from the transmission optical system. The principal ray of the reference ray is a ray that passes through the center of the aperture stop among the rays that are projected closest to the projection optical system on the projection surface. The projection optical system has an intermediate image plane conjugate with the reduction-side image plane between the transmission optical system and the reflection optical system, and satisfies the following conditional expression (1).
　０．７０＜｜Ｐｅｘ｜／Ｔｌ＜４０・・・（１）
　ここで、Ｔｌは、複数のレンズのうち最も縮小側のレンズから、複数のレンズのうち最も被投写面側のレンズまでの距離である。Ｐｅｘは、基準光線の主光線を基準とした透過光学系の射出瞳位置から、複数のレンズのうち最も被投写面側のレンズまでの基準光線の主光線の光路長のうち最大の距離である。 0.70 <| Pex | / Tl <40 (1)
Here, Tl is the distance from the most reduced lens among the plurality of lenses to the lens closest to the projection surface among the plurality of lenses. Pex is the maximum distance among the optical path lengths of the principal rays of the reference rays from the exit pupil position of the transmission optical system with reference to the principal ray of the reference rays to the lens closest to the projection surface among the plurality of lenses. .
　本開示に係る画像投写装置は、上記の投写光学系と、画像を形成し、縮小側の像面として画像の表示面を有する画像形成素子とを備える。 An image projection apparatus according to the present disclosure includes the above-described projection optical system and an image forming element that forms an image and has an image display surface as a reduction-side image surface.
　本開示における投写光学系および画像投写装置によれば、画像投写装置を小型化できるとともに、画像歪みを低減することができる。 According to the projection optical system and the image projection device of the present disclosure, the image projection device can be reduced in size and image distortion can be reduced.
図１は、本開示の画像投写システムを説明する図である。FIG. 1 is a diagram illustrating an image projection system according to the present disclosure. 図２は、本開示の画像投写装置を説明する構成図である。FIG. 2 is a configuration diagram illustrating an image projection apparatus according to the present disclosure. 図３は、数値実施例１における透過光学系の構成図である。FIG. 3 is a configuration diagram of a transmission optical system in Numerical Example 1. 図４は、数値実施例２における透過光学系の構成図である。FIG. 4 is a configuration diagram of a transmission optical system in Numerical Example 2. 図５は、数値実施例３における透過光学系の構成図である。FIG. 5 is a configuration diagram of a transmission optical system in Numerical Example 3. 図６は、数値実施例４における透過光学系の構成図である。FIG. 6 is a configuration diagram of a transmission optical system in Numerical Example 4. 図７は、数値実施例５における透過光学系の構成図である。FIG. 7 is a configuration diagram of a transmission optical system in Numerical Example 5.
　以下、適宜図面を参照しながら、実施の形態を詳細に説明する。但し、必要以上に詳細な説明は省略する場合がある。例えば、既によく知られた事項の詳細説明や実質的に同一の構成に対する重複説明を省略する場合がある。これは、以下の説明が不必要に冗長になるのを避け、当業者の理解を容易にするためである。 Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.
　なお、添付図面および以下の説明は、当業者が本開示を十分に理解するために、提供されるのであって、これらにより請求の範囲に記載の主題を限定することは意図されていない。 The accompanying drawings and the following description are provided for those skilled in the art to fully understand the present disclosure, and are not intended to limit the claimed subject matter.
　（実施の形態）
　以下、本開示の画像投写装置１０を図１から図７を用いて説明する。 (Embodiment)
Hereinafter, the image projection apparatus 10 of the present disclosure will be described with reference to FIGS. 1 to 7.
　図１は、本開示の画像投写システム１を説明する図である。画像投写システム１は、画像投写装置１０と、スクリーンＳＣ（被投写面の一例）とを備える。画像投写装置１０は、投写光学系１００と、画像表示素子１３０と、透過素子１４０とから構成される。投写光学系１００は、透過光学系１１０と、反射光学系１２０とを備える。画像投写装置１０は、画像表示素子１３０で形成された画像を正対しない方向（斜めの方向）にあるスクリーンＳＣに投写する。ここで、スクリーンＳＣが正対しない方向にあるとは、基準光線Ｒが到達するスクリーンＳＣ上の点における法線の方向と、投写光学系１００の最終面から出射する基準光線Ｒの主光線光路の方向とが一致しない場合を言う。 FIG. 1 is a diagram illustrating an image projection system 1 according to the present disclosure. The image projection system 1 includes an image projection device 10 and a screen SC (an example of a projection surface). The image projection apparatus 10 includes a projection optical system 100, an image display element 130, and a transmission element 140. The projection optical system 100 includes a transmission optical system 110 and a reflection optical system 120. The image projection device 10 projects the image formed by the image display element 130 onto the screen SC in a direction (diagonal direction) that does not face the image. Here, the direction in which the screen SC does not face is that the direction of the normal line at the point on the screen SC where the reference ray R reaches and the principal ray optical path of the reference ray R emitted from the final surface of the projection optical system 100. Say when the direction does not match.
　なお、本開示にかかる画像投写装置１０において、透過光学系１１０の開口絞りＡ（図２参照）の中心と、開口絞りＡの縮小側に配置されたレンズ素子の回転対称軸と、開口絞りＡの拡大側に配置されたレンズ素子の回転対称軸とを結ぶ直線を光軸ＡＺとする。しかしながら、光軸ＡＺは、最も多くのレンズ中心を共有する軸としてもよい。また、光軸ＡＺは、画像表示素子１３０に対し、出射光の光路を含む面内で偏心した位置に設定されてもよい。ここで、出射光の光路とは、画像表示素子１３０からスクリーンＳＣに至る光路における、画像表示素子１３０の中心からスクリーンＳＣ上の拡大像の中心に至る主光線の光路を意味する。 In the image projection apparatus 10 according to the present disclosure, the center of the aperture stop A (see FIG. 2) of the transmission optical system 110, the rotational symmetry axis of the lens element disposed on the reduction side of the aperture stop A, and the aperture stop A A straight line connecting the rotationally symmetric axes of the lens elements arranged on the enlargement side is defined as an optical axis AZ. However, the optical axis AZ may be an axis that shares the most lens centers. Further, the optical axis AZ may be set at a position eccentric with respect to the image display element 130 in a plane including the optical path of the emitted light. Here, the optical path of the emitted light means the optical path of the principal ray from the center of the image display element 130 to the center of the enlarged image on the screen SC in the optical path from the image display element 130 to the screen SC.
　なお、本開示において、縮小側とは、投写光学系１００において画像表示素子１３０側を意味する。また、拡大側とは、投写光学系１００においてスクリーンＳＣ側を意味する。また、基準光線Ｒの主光線とは、スクリーンＳＣの最も投写光学系１００側に投写される光線のうち開口絞りＡの中心を通る光線である。 In the present disclosure, the reduction side means the image display element 130 side in the projection optical system 100. Further, the enlargement side means the screen SC side in the projection optical system 100. The principal ray of the reference ray R is a ray that passes through the center of the aperture stop A among the rays that are projected closest to the projection optical system 100 of the screen SC.
　また、画像投写装置１０が透過光学系１１０内にプリズムやミラーなどの反射面を有する場合には、光軸ＡＺは、当該反射面で反射して曲げられた後の光学系の光軸の延長線として設定されてもよい。 When the image projection apparatus 10 has a reflecting surface such as a prism or a mirror in the transmission optical system 110, the optical axis AZ is an extension of the optical axis of the optical system after being reflected and bent by the reflecting surface. It may be set as a line.
　また、本開示にかかる画像投写装置１０は曲率を有するスクリーンＳＣに画像を投写する。 Also, the image projection apparatus 10 according to the present disclosure projects an image on a screen SC having a curvature.
　図２は、本開示の画像投写装置１０を説明する構成図である。投写光学系１００は、全体として正のパワーを有する透過光学系１１０と、全体として正のパワーを有する反射光学系１２０とを備える。図２に示すように、開口絞りＡの中心を通る基準光線Ｒの主光線は、縮小側の像面から開口絞りＡまでの間で光軸ＡＺと交わらない。 FIG. 2 is a configuration diagram illustrating the image projection device 10 of the present disclosure. The projection optical system 100 includes a transmission optical system 110 having a positive power as a whole and a reflection optical system 120 having a positive power as a whole. As shown in FIG. 2, the principal ray of the reference ray R passing through the center of the aperture stop A does not intersect the optical axis AZ between the image plane on the reduction side and the aperture stop A.
　図３～図７を参照して、透過光学系１１０について説明する。透過光学系１１０は、正のパワーを有する第１レンズ群Ｇ１と、正のパワーを有する第２レンズ群Ｇ２と、正のパワーを有する第３レンズ群Ｇ３と、正のパワーを有する第４レンズ群Ｇ４と、プリズムＰＢから構成されている。第１レンズ群Ｇ１、第２レンズ群Ｇ２、第３レンズ群Ｇ３および第４レンズ群Ｇ４は、画像表示素子１３０からスクリーンＳＣまでの順に配置されている。プリズムＰＢは、画像表示素子１３０と第１レンズ群Ｇ１との間に配置されている。なお、本開示において、プリズムＰＢはパワーを有しない。そのため、例えば図３の透過光学系１１０において、パワーを有する複数のレンズとは、レンズ素子Ｌ１～Ｌ１４を意味する。 The transmission optical system 110 will be described with reference to FIGS. The transmission optical system 110 includes a first lens group G1 having positive power, a second lens group G2 having positive power, a third lens group G3 having positive power, and a fourth lens having positive power. It consists of a group G4 and a prism PB. The first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 are arranged in order from the image display element 130 to the screen SC. The prism PB is disposed between the image display element 130 and the first lens group G1. In the present disclosure, the prism PB has no power. Therefore, for example, in the transmission optical system 110 of FIG. 3, the plurality of lenses having power means the lens elements L1 to L14.
　第１レンズ群Ｇ１は、回転対称な軸を有する１枚の両凸レンズである第１レンズ素子Ｌ１から構成されている。第１レンズ素子Ｌ１は、非球面形状を有する。 The first lens group G1 includes a first lens element L1 that is a single biconvex lens having a rotationally symmetric axis. The first lens element L1 has an aspheric shape.
　第２レンズ群Ｇ２は、第２レンズ素子Ｌ２と、第３レンズ素子Ｌ３と、第４レンズ素子Ｌ４と、第５レンズ素子Ｌ５とを備える。第２レンズ素子Ｌ２は、回転対称な軸を有し、負のメニスカス形状を有する。第２レンズ素子Ｌ２の凸面は、縮小側を向いている。第３レンズ素子Ｌ３は、回転対称な軸を有し、両凸形状を有する。第４レンズ素子Ｌ４は、回転対称な軸を有し、両凹形状を有する。第５レンズ素子Ｌ５は、回転対称な軸を有し、両凸形状を有する。第２レンズ素子Ｌ２と第３レンズ素子Ｌ３と第４レンズ素子Ｌ４は互いに接合されている。 The second lens group G2 includes a second lens element L2, a third lens element L3, a fourth lens element L4, and a fifth lens element L5. The second lens element L2 has a rotationally symmetric axis and has a negative meniscus shape. The convex surface of the second lens element L2 faces the reduction side. The third lens element L3 has a rotationally symmetric axis and has a biconvex shape. The fourth lens element L4 has a rotationally symmetric axis and has a biconcave shape. The fifth lens element L5 has a rotationally symmetric axis and has a biconvex shape. The second lens element L2, the third lens element L3, and the fourth lens element L4 are cemented with each other.
　以下、図３、４、５および７を参照して、数値実施例１、２、３および５について説明する。 Hereinafter, numerical examples 1, 2, 3, and 5 will be described with reference to FIGS.
　第３レンズ群Ｇ３は、開口絞りＡを備え、全体として正のパワーを有する。また、第３レンズ群Ｇ３は、第６レンズ素子Ｌ６と、第７レンズ素子Ｌ７と、第８レンズ素子Ｌ８と、第９レンズ素子Ｌ９と、第１０レンズ素子Ｌ１０とを備える。第６レンズ素子Ｌ６は、開口絞りＡよりも拡大側に配置され、回転対称な軸を有し、正のメニスカス形状を有する。第６レンズ素子Ｌ６の凸面は、拡大側を向いている。第７レンズ素子Ｌ７（負のメニスカスレンズ）は、回転対称な軸を有し、負のメニスカス形状を有する。第７レンズ素子Ｌ７の凸面は、拡大側を向いている。第８レンズ素子Ｌ８は、回転対称な軸を有し、正のメニスカス形状を有する。第８レンズ素子Ｌ８の凸面は、縮小側を向いている。第９レンズ素子Ｌ９は、回転対称な軸を有し、両凸形状を有する。第１０レンズ素子Ｌ１０は、回転対称な軸を有し、負のメニスカス形状を有する。第１０レンズ素子Ｌ１０の凸面は、拡大側を向いている。 The third lens group G3 includes an aperture stop A and has a positive power as a whole. The third lens group G3 includes a sixth lens element L6, a seventh lens element L7, an eighth lens element L8, a ninth lens element L9, and a tenth lens element L10. The sixth lens element L6 is disposed on the enlargement side with respect to the aperture stop A, has a rotationally symmetric axis, and has a positive meniscus shape. The convex surface of the sixth lens element L6 faces the enlargement side. The seventh lens element L7 (negative meniscus lens) has a rotationally symmetric axis and has a negative meniscus shape. The convex surface of the seventh lens element L7 faces the enlargement side. The eighth lens element L8 has a rotationally symmetric axis and has a positive meniscus shape. The convex surface of the eighth lens element L8 faces the reduction side. The ninth lens element L9 has a rotationally symmetric axis and has a biconvex shape. The tenth lens element L10 has a rotationally symmetric axis and has a negative meniscus shape. The convex surface of the tenth lens element L10 faces the enlargement side.
　第４レンズ群Ｇ４は、透過光学系１１０のレンズ群の内、最もスクリーンＳＣ側に配置されている。第４レンズ群Ｇ４は、第１１レンズ素子Ｌ１１と、第１２レンズ素子Ｌ１２と、第１３レンズ素子Ｌ１３と、第１４レンズ素子Ｌ１４とを備える。第１１レンズ素子Ｌ１１、第１２レンズ素子Ｌ１２、第１３レンズ素子Ｌ１３および第１４レンズ素子Ｌ１４は、画像表示素子１３０からスクリーンＳＣまでの順に配置されている。第１１レンズ素子Ｌ１１は、回転対称な軸を有し、正のパワーを有する。第１１レンズ素子Ｌ１１の凸面は、縮小側を向いている。第１２レンズ素子Ｌ１２は、回転対称な軸を有し、負のパワーを有する。第１２レンズ素子Ｌ１２の凹面は、拡大側を向いている。第１３レンズ素子Ｌ１３は、回転対称な軸を有し、両凹形状を有する。第１４レンズ素子Ｌ１４は、回転対称な軸を有し、正のメニスカス形状を有する。第１４レンズ素子Ｌ１４の凸面は、拡大側を向いている。 The fourth lens group G4 is arranged closest to the screen SC among the lens groups of the transmission optical system 110. The fourth lens group G4 includes an eleventh lens element L11, a twelfth lens element L12, a thirteenth lens element L13, and a fourteenth lens element L14. The eleventh lens element L11, the twelfth lens element L12, the thirteenth lens element L13, and the fourteenth lens element L14 are arranged in order from the image display element 130 to the screen SC. The eleventh lens element L11 has a rotationally symmetric axis and has positive power. The convex surface of the eleventh lens element L11 faces the reduction side. The twelfth lens element L12 has a rotationally symmetric axis and has negative power. The concave surface of the twelfth lens element L12 faces the enlargement side. The thirteenth lens element L13 has a rotationally symmetric axis and has a biconcave shape. The fourteenth lens element L14 has a rotationally symmetric axis and has a positive meniscus shape. The convex surface of the fourteenth lens element L14 faces the enlargement side.
　第１１レンズ素子Ｌ１１と第１２レンズ素子Ｌ１２は互いに接合されている。また、第１３レンズ素子Ｌ１３と、第１４レンズ素子Ｌ１４は非球面形状を有するレンズ素子となる。 The eleventh lens element L11 and the twelfth lens element L12 are cemented with each other. The thirteenth lens element L13 and the fourteenth lens element L14 are lens elements having an aspherical shape.
　以下、図６を参照して、数値実施例４について説明する。 Hereinafter, numerical example 4 will be described with reference to FIG.
　第３レンズ群Ｇ３は、開口絞りＡを備え、全体として正のパワーを有する。また、第３レンズ群Ｇ３は、第６レンズ素子Ｌ６と、第７レンズ素子Ｌ７と、第８レンズ素子Ｌ８と、第９レンズ素子Ｌ９と、第１０レンズ素子Ｌ１０とを備える。第６レンズ素子Ｌ６は、開口絞りＡよりも拡大側に配置され、回転対称な軸を有し、正のメニスカス形状を有する。第６レンズ素子Ｌ６の凸面は、拡大側を向いている。第７レンズ素子Ｌ７（負のメニスカスレンズ）は、回転対称な軸を有し、負のメニスカス形状を有する。第７レンズ素子Ｌ７の凸面は、拡大側を向いている。第８レンズ素子Ｌ８は、回転対称な軸を有し、正のパワーを有する。第８レンズ素子Ｌ８の凸面は、縮小側を向いている。第９レンズ素子Ｌ９は、回転対称な軸を有し、両凹形状を有する。第１０レンズ素子Ｌ１０は、回転対称な軸を有し、両凸形状を有する。第９レンズ素子Ｌ９と第１０レンズ素子Ｌ１０は互いに接合されている。 The third lens group G3 includes an aperture stop A and has a positive power as a whole. The third lens group G3 includes a sixth lens element L6, a seventh lens element L7, an eighth lens element L8, a ninth lens element L9, and a tenth lens element L10. The sixth lens element L6 is disposed on the enlargement side with respect to the aperture stop A, has a rotationally symmetric axis, and has a positive meniscus shape. The convex surface of the sixth lens element L6 faces the enlargement side. The seventh lens element L7 (negative meniscus lens) has a rotationally symmetric axis and has a negative meniscus shape. The convex surface of the seventh lens element L7 faces the enlargement side. The eighth lens element L8 has a rotationally symmetric axis and has positive power. The convex surface of the eighth lens element L8 faces the reduction side. The ninth lens element L9 has a rotationally symmetric axis and has a biconcave shape. The tenth lens element L10 has a rotationally symmetric axis and has a biconvex shape. The ninth lens element L9 and the tenth lens element L10 are cemented with each other.
　第４レンズ群Ｇ４は、透過光学系１１０の内、最もスクリーンＳＣ側に配置されている。第４レンズ群Ｇ４は、第１１レンズ素子Ｌ１１と、第１２レンズ素子Ｌ１２と、第１３レンズ素子Ｌ１３とを備える。第１１レンズ素子Ｌ１１、第１２レンズ素子Ｌ１２および第１３レンズ素子Ｌ１３は、画像表示素子１３０からスクリーンＳＣまでの順に配置されている。第１１レンズ素子Ｌ１１は、回転対称な軸を有し、正のメニスカス形状を有する。第１１レンズ素子Ｌ１１の凸面は、縮小側を向いている。第１２レンズ素子Ｌ１２は、回転対称な軸を有し、両凹形状を有する。第１３レンズ素子Ｌ１３は、回転対称な軸を有し、正のメニスカス形状を有する。第１３レンズ素子Ｌ１３の凸面は、拡大側を向いている。 The fourth lens group G4 is disposed closest to the screen SC in the transmission optical system 110. The fourth lens group G4 includes an eleventh lens element L11, a twelfth lens element L12, and a thirteenth lens element L13. The eleventh lens element L11, the twelfth lens element L12, and the thirteenth lens element L13 are arranged in order from the image display element 130 to the screen SC. The eleventh lens element L11 has a rotationally symmetric axis and has a positive meniscus shape. The convex surface of the eleventh lens element L11 faces the reduction side. The twelfth lens element L12 has a rotationally symmetric axis and has a biconcave shape. The thirteenth lens element L13 has a rotationally symmetric axis and has a positive meniscus shape. The convex surface of the thirteenth lens element L13 faces the enlargement side.
　第１２レンズ素子Ｌ１２と、第１３レンズ素子Ｌ１３は非球面形状を有するレンズ素子である。 The twelfth lens element L12 and the thirteenth lens element L13 are lens elements having an aspherical shape.
　以下、数値実施例１、２、３、４、５に共通する特徴について説明する。 Hereinafter, features common to Numerical Examples 1, 2, 3, 4, and 5 will be described.
　最投写側レンズの画像表示素子１３０側に隣接するレンズ、または、第４レンズ群Ｇ４を構成する一部のレンズ素子は、両凹形状を有している。この両凹形状のレンズの少なくとも一方の面が非球面形状を有することが望ましい。具体的には、この非球面形状は、レンズの中心から径方向に離れるに従って、曲率が小さくなる形状である。すなわち、この非球面形状は、レンズの中心側に比べてレンズの外側のパワーが小さい形状である。 The lens adjacent to the image display element 130 side of the most projected side lens or a part of the lens elements constituting the fourth lens group G4 has a biconcave shape. It is desirable that at least one surface of the biconcave lens has an aspherical shape. Specifically, this aspherical shape is a shape in which the curvature decreases with increasing distance from the center of the lens in the radial direction. That is, this aspherical shape is a shape in which the power on the outer side of the lens is smaller than that on the lens center side.
　第３レンズ素子Ｌ３（正レンズ）は、レンズ素子のうちで最も強い正のパワーを有していてもよい。第４レンズ素子Ｌ４（負レンズ）は、レンズ素子のうちで最も強い負のパワーを有していてもよい。図３～図７において、第３レンズ素子Ｌ３と第４レンズ素子Ｌ４とは接合されているが、接合されることなく隣接して配置されていてもよい。 The third lens element L3 (positive lens) may have the strongest positive power among the lens elements. The fourth lens element L4 (negative lens) may have the strongest negative power among the lens elements. 3 to 7, the third lens element L3 and the fourth lens element L4 are joined, but they may be arranged adjacent to each other without being joined.
　なお、投写光学系１００は、第２レンズ群Ｇ２と第４レンズ群Ｇ４の２つのレンズ群でフォーカスしている。第４レンズ群Ｇ４は、非球面形状を少なくとも１面含み、フォーカス時に発生する像の歪みや解像度の劣化を抑制している。これにより、投写距離が変わっても良好な光学性能を満たせる。 Note that the projection optical system 100 is focused by two lens groups, the second lens group G2 and the fourth lens group G4. The fourth lens group G4 includes at least one aspheric surface, and suppresses image distortion and resolution degradation that occur during focusing. Thereby, good optical performance can be satisfied even if the projection distance changes.
　また、投写光学系１００は、開口絞りＡよりも拡大側の一部のレンズ素子、または複数のレンズ素子をフォーカス群として採用することで、フォーカス時に発生する像の歪みや解像度の劣化を抑制することも可能である。これにより、投写距離が変わっても良好な光学性能を満たせる。 In addition, the projection optical system 100 uses a part of the lens elements or a plurality of lens elements on the enlargement side of the aperture stop A as a focus group, thereby suppressing image distortion and resolution degradation that occur during focusing. It is also possible. Thereby, good optical performance can be satisfied even if the projection distance changes.
　最投写側の第４レンズ群Ｇ４において、正メニスカス形状の最拡大側レンズの凹面と、正メニスカス形状のレンズまたは正レンズ素子と接合されている負レンズ素子の拡大側の凹面は、互いに向かい合っている。 In the fourth lens group G4 on the most projection side, the concave surface of the positive meniscus-shaped maximum magnification side lens and the concave surface on the expansion side of the negative meniscus lens or the negative lens element joined to the positive lens element face each other. Yes.
　また、第４レンズ群Ｇ４は、最もスクリーンＳＣ側に、最投写側レンズを有する。この最投写側レンズは、透過光学系１１０において最も偏肉比が大きい形状を有している。これにより、透過する光束の中心と周辺との屈折力差を大きくできるため、像面湾曲の補正に有効である。 The fourth lens group G4 has the most projection side lens on the most screen SC side. The most projection side lens has a shape with the largest thickness deviation ratio in the transmission optical system 110. As a result, the difference in refractive power between the center and the periphery of the transmitted light beam can be increased, which is effective in correcting field curvature.
　透過光学系１１０を構成する複数のレンズ素子の一部をカットすることで、透過光学系１１０の低背化に効果が期待できる。特に、縮小側に配置されたレンズ素子や、拡大側に配置されたレンズ素子など、開口絞りＡから離れたレンズ素子の一部をカットすることで、より一層の低背化効果が期待できる。なお、カットを行ったレンズ素子は回転対称な軸を有さない。 By cutting a part of the plurality of lens elements constituting the transmission optical system 110, an effect can be expected to reduce the height of the transmission optical system 110. In particular, by cutting a part of the lens elements away from the aperture stop A, such as a lens element arranged on the reduction side and a lens element arranged on the enlargement side, a further reduction in height can be expected. Note that the cut lens element does not have a rotationally symmetric axis.
　透過光学系１１０とスクリーンＳＣとの間に中間像面Ｉ（図２参照）が結像される。こうすることで、反射光学系１２０の一部に凹面ミラーを採用することが可能となり、投写領域の拡大と反射光学系１２０の小型化に有利な構成となる。また、透過光学系１１０で形成される中間像面Ｉは、光軸ＡＺに最も近い光線による結像点が透過光学系１１０から最も離れた位置に形成される特徴を有している。中間像面Ｉは、反射光学系１２０の反射面を跨がない位置に結像することが望ましい。 An intermediate image plane I (see FIG. 2) is formed between the transmission optical system 110 and the screen SC. This makes it possible to employ a concave mirror as a part of the reflective optical system 120, which is advantageous for enlarging the projection area and reducing the size of the reflective optical system 120. Further, the intermediate image plane I formed by the transmission optical system 110 has a characteristic that an image point formed by a light ray closest to the optical axis AZ is formed at a position farthest from the transmission optical system 110. The intermediate image plane I is preferably formed at a position that does not straddle the reflection surface of the reflection optical system 120.
　反射光学系１２０は、透過光学系１１０が出射する光束を反射し、反射した光束をスクリーンＳＣに投写する。反射光学系１２０は、第１ミラー１２１（凹面ミラーの一例）と第２ミラー１２２（平面ミラーの一例）の２枚のミラーから構成される。第１ミラー１２１の反射面は、凹面の自由曲面形状を有している。第１ミラー１２１は、全体として正のパワーを有する。なお、反射光学系１２０は、１枚以上のミラーから構成されればよく、２枚のミラーから構成されることに限定されるものではない。 The reflection optical system 120 reflects the light beam emitted from the transmission optical system 110 and projects the reflected light beam onto the screen SC. The reflective optical system 120 includes two mirrors, a first mirror 121 (an example of a concave mirror) and a second mirror 122 (an example of a plane mirror). The reflecting surface of the first mirror 121 has a concave free-form surface. The first mirror 121 has a positive power as a whole. The reflection optical system 120 only needs to be composed of one or more mirrors, and is not limited to being composed of two mirrors.
　画像表示素子１３０は、画像信号を基にスクリーンＳＣに投写する画像を形成する。画像表示素子１３０としては、ＤＭＤ（Ｄｉｇｉｔａｌ　Ｍｉｃｒｏｍｉｒｒｏｒ　Ｄｅｖｉｃｅ）や透過型や反射型の液晶パネル等の空間変調素子を用いることができる。本開示における画像表示素子１３０は、図２のＸ軸方向（紙面垂直方向）が長辺、Ｙ軸方向が短辺の矩形である。 The image display element 130 forms an image to be projected on the screen SC based on the image signal. As the image display element 130, a spatial modulation element such as a DMD (Digital Micromirror Device) or a transmissive or reflective liquid crystal panel can be used. The image display element 130 according to the present disclosure is a rectangle having a long side in the X-axis direction (perpendicular to the paper surface) in FIG. 2 and a short side in the Y-axis direction.
　透過素子１４０は、反射光学系１２０とスクリーンＳＣとの間に配置される。反射光学系１２０が反射した光束は、透過素子１４０を透過してスクリーンＳＣに投写される。また、透過素子１４０の形状は、画像表示素子１３０の長辺方向に対応した方向と短辺方向に対応した方向とで異なる曲率を有するトロイダル形状である。透過素子１４０の凸面は、スクリーンＳＣ側を向いている。すなわち、透過素子１４０の入射面における画像表示素子１３０の長辺方向に対応するＸ軸方向（図２の紙面垂直方向）の曲率は、短辺方向に対応するＹ軸方向の曲率よりも大きい。 The transmissive element 140 is disposed between the reflective optical system 120 and the screen SC. The light beam reflected by the reflective optical system 120 is transmitted through the transmissive element 140 and projected onto the screen SC. The shape of the transmissive element 140 is a toroidal shape having different curvatures in a direction corresponding to the long side direction of the image display element 130 and a direction corresponding to the short side direction. The convex surface of the transmissive element 140 faces the screen SC side. That is, the curvature in the X-axis direction (perpendicular to the paper surface in FIG. 2) corresponding to the long side direction of the image display element 130 on the incident surface of the transmission element 140 is larger than the curvature in the Y-axis direction corresponding to the short side direction.
　また、反射光学系１２０において、画像表示素子１３０側の第１ミラー１２１は、自由曲面形状を有することが望ましい。第１ミラー１２１が正のパワーを有する自由曲面形状を有することで、像歪み補正をしつつ、第２ミラー１２２に入射する光線高を抑制できる。そのため、小型化に有利である。 In the reflective optical system 120, the first mirror 121 on the image display element 130 side preferably has a free-form surface shape. Since the first mirror 121 has a free-form surface having a positive power, it is possible to suppress the height of light incident on the second mirror 122 while correcting image distortion. Therefore, it is advantageous for downsizing.
　最もスクリーンＳＣ側に配置される第１３レンズ素子Ｌ１３（図６参照）または第１４レンズ素子Ｌ１４（図３、４、５または７参照）から自由曲面の反射面を有する第１ミラー１２１までの距離は、第１ミラー１２１から第２ミラー１２２までの距離よりも長い。これにより、第１ミラー１２１と第２ミラー１２２の間隔を短縮でき、投写光学系１００のＹ軸方向の低背化ができる。 Distance from the thirteenth lens element L13 (see FIG. 6) or the fourteenth lens element L14 (see FIG. 3, 4, 5 or 7) arranged closest to the screen SC to the first mirror 121 having a free-form reflecting surface Is longer than the distance from the first mirror 121 to the second mirror 122. Thereby, the space | interval of the 1st mirror 121 and the 2nd mirror 122 can be shortened, and the height of the projection optical system 100 in the Y-axis direction can be reduced.
　以下、本実施の形態に係る投写光学系が満足することが好ましい条件を説明する。なお、実施の形態に係る投写光学系に対して、複数の条件が規定されるが、これら複数の条件すべてを満足する投写光学系の構成が最も望ましい。しかしながら、個別の条件を満足することにより、それぞれ対応する効果を奏する投写光学系を得ることも可能である。 Hereinafter, conditions that are preferably satisfied by the projection optical system according to the present embodiment will be described. Although a plurality of conditions are defined for the projection optical system according to the embodiment, a configuration of the projection optical system that satisfies all of the plurality of conditions is most desirable. However, by satisfying individual conditions, it is possible to obtain a projection optical system that exhibits the corresponding effects.
　本実施の形態に係る投写光学系１００は、スクリーンＳＣに画像を投写するために用いられ、縮小側の像面とスクリーンＳＣ側の像面とを共役の関係にする投写光学系であって、透過光学系１１０と、反射光学系１２０とを備える。透過光学系１１０は、開口絞りＡと、それぞれパワーを有する複数のレンズとを含む。反射光学系１２０は、透過光学系１１０からの出射光を反射する。基準光線Ｒの主光線は、スクリーンＳＣの最も投写光学系１００側に投写される光線のうち開口絞りＡの中心を通る光線である。投写光学系１００は、縮小側の像面と共役な中間像面Ｉを透過光学系１１０と反射光学系１２０の間に有している。以下、この構成を実施の形態の基本構成という。 A projection optical system 100 according to the present embodiment is a projection optical system that is used for projecting an image on a screen SC and has a conjugate relationship between a reduction-side image plane and a screen SC-side image plane. A transmission optical system 110 and a reflection optical system 120 are provided. The transmission optical system 110 includes an aperture stop A and a plurality of lenses each having power. The reflection optical system 120 reflects light emitted from the transmission optical system 110. The principal ray of the reference ray R is a ray that passes through the center of the aperture stop A among the rays that are projected closest to the projection optical system 100 of the screen SC. The projection optical system 100 has an intermediate image plane I conjugate with the reduction-side image plane between the transmission optical system 110 and the reflection optical system 120. Hereinafter, this configuration is referred to as a basic configuration of the embodiment.
　投写光学系１００は、以下の条件式（１）を満足することが好ましい。 The projection optical system 100 preferably satisfies the following conditional expression (1).
　０．７０　＜　｜Ｐｅｘ｜／Ｔｌ　＜　４０　・・・（１）
　ここで、Ｔｌは、最も縮小側のレンズから、最もスクリーンＳＣ側のレンズまでの距離である。｜Ｐｅｘ｜は、基準光線Ｒの主光線を基準とした透過光学系１１０の射出瞳位置から、最もスクリーンＳＣ側のレンズまでの基準光線Ｒの主光線の光路長のうち最大の距離である。 0.70 <| Pex | / Tl <40 (1)
Here, Tl is the distance from the most reduction side lens to the most screen SC side lens. | Pex | is the maximum distance in the optical path length of the principal ray of the reference ray R from the exit pupil position of the transmission optical system 110 with respect to the principal ray of the reference ray R to the lens closest to the screen SC.
　条件式（１）は、透過光学系１１０の基準光線Ｒの主光線を基準（その光線の光軸）とした射出瞳位置と全長との好適な範囲を規定している。ここで、基準光線Ｒは、投写光学系１００を備えた画像投写装置１０がスクリーンＳＣの最も手前側に投写する光線である。条件式（１）を満足することで、小型でありながら画像歪みの低減された投写光学系１００とすることが可能である。｜Ｐｅｘ｜／Ｔｌが条件式（１）の上限を超えると、投写光学系１００はテレセントリック光学系に近い構成となる。しかし、像面湾曲を適切に補正すると透過光学系１１０のサイズが大きくなる。そのため、投写光学系１００の小型化に不利となる。反対に、｜Ｐｅｘ｜／Ｔｌが条件式（１）の下限を下回ると、透過光学系１１０からの射出光線が広がり、反射光学系１２０のサイズが大きくなる。そのため、投写光学系１００の小型化に不利となる。 Conditional expression (1) defines a preferable range between the exit pupil position and the total length with the principal ray of the reference ray R of the transmission optical system 110 as a reference (the optical axis of the ray). Here, the reference light beam R is a light beam projected by the image projection apparatus 10 including the projection optical system 100 to the foremost side of the screen SC. By satisfying conditional expression (1), it is possible to provide a projection optical system 100 that is small in size and reduced in image distortion. When | Pex | / Tl exceeds the upper limit of the conditional expression (1), the projection optical system 100 has a configuration close to a telecentric optical system. However, when the curvature of field is appropriately corrected, the size of the transmission optical system 110 increases. This is disadvantageous for downsizing of the projection optical system 100. On the other hand, when | Pex | / Tl falls below the lower limit of the conditional expression (1), the emitted light from the transmission optical system 110 spreads and the size of the reflection optical system 120 increases. This is disadvantageous for downsizing of the projection optical system 100.
　さらに、以下の条件式（１ａ）を満足することで、上記した効果をより奏功することができる。 Furthermore, by satisfying the following conditional expression (1a), the above-described effects can be achieved more effectively.
　０．８０　＜　｜Ｐｅｘ｜／Ｔｌ　＜　３０　・・・（１ａ）
　さらに、以下の条件式（１ｂ）を満足することで、上記した効果をより奏功することができる。 0.80 <| Pex | / Tl <30 (1a)
Furthermore, when the following conditional expression (1b) is satisfied, the above-described effects can be more effectively achieved.
　０．９０　＜　｜Ｐｅｘ｜／Ｔｌ　＜　２０　・・・（１ｂ）
　さらに、以下の条件式（１ｃ）を満足することで、上記した効果をより奏功することができる。 0.90 <| Pex | / Tl <20 (1b)
Furthermore, when the following conditional expression (1c) is satisfied, the above-described effects can be more effectively achieved.
　１．００　＜　｜Ｐｅｘ｜／Ｔｌ　＜　１７　・・・（１ｃ）
　本開示に係る投写光学系１００は、以下の条件式（２）を満足することが好ましい。 1.00 <| Pex | / Tl <17 (1c)
The projection optical system 100 according to the present disclosure preferably satisfies the following conditional expression (2).
　１．００　＜　｜Ｐｉｎ｜／Ｔｌ　＜　５０　・・・（２）
　ここで、｜Ｐｉｎ｜は、基準光線Ｒの主光線を基準とした透過光学系１１０の入射瞳位置から、最も縮小側のレンズまでの基準光線Ｒの主光線の光路長のうち最大の距離である。 1.00 <| Pin | / Tl <50 (2)
Here, | Pin | is the maximum distance in the optical path length of the principal ray of the reference ray R from the entrance pupil position of the transmission optical system 110 with reference to the principal ray of the reference ray R to the lens on the most reduced side. is there.
　条件式（２）は、透過光学系１１０の基準光線Ｒの主光線を基準（その光線の光軸）とした入射瞳位置と全長との好適な範囲を規定している。｜Ｐｉｎ｜／Ｔｌが条件式（２）の下限を下回ると、像面から入射する光線角度が大きくなり、表示素子としてＤＭＤを使用した場合の光量ロスが顕著となる。そのため、スクリーンＳＣ上の照度分布均一性を維持することが困難となる。反対に、｜Ｐｉｎ｜／Ｔｌが条件式（２）の上限を超えると、投写光学系１００に対する透過光学系１１０の全長が短くなり、像面湾曲を良好に維持することが困難となる。 Conditional expression (2) defines a preferable range of the entrance pupil position and the total length with the principal ray of the reference ray R of the transmission optical system 110 as a reference (the optical axis of the ray). When | Pin | / Tl falls below the lower limit of the conditional expression (2), the angle of light incident from the image plane increases, and the light loss when the DMD is used as the display element becomes significant. Therefore, it becomes difficult to maintain the illuminance distribution uniformity on the screen SC. On the contrary, if | Pin | / Tl exceeds the upper limit of the conditional expression (2), the total length of the transmission optical system 110 with respect to the projection optical system 100 becomes short, and it becomes difficult to maintain the field curvature well.
　さらに、以下の条件式（２ａ）を満足することで、上記した効果をより奏功することができる。 Furthermore, by satisfying the following conditional expression (2a), the above-described effects can be achieved more effectively.
　１．２５　＜　｜Ｐｉｎ｜／Ｔｌ　＜　４５　・・・（２ａ）
　さらに、以下の条件式（２ｂ）を満足することで、上記した効果をより奏功することができる。 1.25 <| Pin | / Tl <45 (2a)
Furthermore, when the following conditional expression (2b) is satisfied, the above-described effects can be more effectively achieved.
　１．５０　＜　｜Ｐｉｎ｜／Ｔｌ　＜　４０　・・・（２ｂ）
　さらに、以下の条件式（２ｃ）を満足することで、上記した効果をより奏功することができる。 1.50 <| Pin | / Tl <40 (2b)
Furthermore, when the following conditional expression (2c) is satisfied, the above-described effects can be more effectively achieved.
　１．７５　＜　｜Ｐｉｎ｜／Ｔｌ　＜　３５　・・・（２ｃ）
　さらに、以下の条件式（２ｄ）を満足することで、上記した効果をより奏功することができる。 1.75 <| Pin | / Tl <35 (2c)
Furthermore, when the following conditional expression (2d) is satisfied, the above-described effects can be more effectively achieved.
　２．００　＜　｜Ｐｉｎ｜／Ｔｌ　＜　３２　・・・（２ｄ）
　本開示に係る投写光学系１００は、以下の条件式（３）を満足することが好ましい。 2.00 <| Pin | / Tl <32 (2d)
The projection optical system 100 according to the present disclosure preferably satisfies the following conditional expression (3).
　０．０５０　＜　Ｔｌ／Ｒｆ　＜　５．０　・・・（３）
　ここで、Ｒｆは、基準光線Ｒの主光線を基準とした透過光学系１１０の最大の焦点距離である。 0.050 <Tl / Rf <5.0 (3)
Here, Rf is the maximum focal length of the transmission optical system 110 based on the principal ray of the reference ray R.
　条件式（３）は、基準光線Ｒの主光線を基準（その光線の光軸）とした透過光学系１１０の焦点距離と、全長との好適な範囲を規定している。Ｔｌ／Ｒｆが条件式（３）の下限を下回ると、透過光学系１１０の全長が短くなり、投写光学系１００として十分な光学性能を維持することが困難となる。または、透過光学系１１０の中間像面Ｉが透過光学系１１０から離れる位置に形成されるため、反射光学系１２０が大きくなり投写光学系１００の小型化に不利となる。反対に、Ｔｌ／Ｒｆが条件式（３）の上限を超えると、透過光学系１１０の全長が大きくなり、投写光学系１００の小型化に不利となる。 Conditional expression (3) defines a preferable range between the focal length of the transmission optical system 110 and the total length with the principal ray of the reference ray R as a reference (the optical axis of the ray). When Tl / Rf falls below the lower limit of the conditional expression (3), the total length of the transmission optical system 110 becomes short, and it becomes difficult to maintain sufficient optical performance as the projection optical system 100. Alternatively, since the intermediate image plane I of the transmission optical system 110 is formed at a position away from the transmission optical system 110, the reflection optical system 120 becomes large, which is disadvantageous for downsizing the projection optical system 100. On the contrary, if Tl / Rf exceeds the upper limit of the conditional expression (3), the total length of the transmission optical system 110 is increased, which is disadvantageous for downsizing of the projection optical system 100.
　さらに、以下の条件式（３ａ）を満足することで、上記した効果をより奏功することができる。 Furthermore, by satisfying the following conditional expression (3a), the above-described effects can be achieved more effectively.
　０．０７５　＜　Ｔｌ／Ｒｆ　＜　４．５　・・・（３ａ）
　さらに、以下の条件式（３ｂ）を満足することで、上記した効果をより奏功することができる。 0.075 <Tl / Rf <4.5 (3a)
Furthermore, when the following conditional expression (3b) is satisfied, the above-described effects can be more effectively achieved.
　０．１００　＜　Ｔｌ／Ｒｆ　＜　４．０　・・・（３ｂ）
　さらに、以下の条件式（３ｃ）を満足することで、上記した効果をより奏功することができる。 0.100 <Tl / Rf <4.0 (3b)
Furthermore, when the following conditional expression (3c) is satisfied, the above-described effects can be more effectively achieved.
　０．１２５　＜　Ｔｌ／Ｒｆ　＜　３．５　・・・（３ｃ）
　本開示にかかる投写光学系１００は、以下の条件式（４）を満足することが好ましい。 0.125 <Tl / Rf <3.5 (3c)
The projection optical system 100 according to the present disclosure preferably satisfies the following conditional expression (4).
　０．８０　＜　｜Ｐｅｘａｘ｜／Ｔｌ　＜　１５　・・・（４）
　ここで、｜Ｐｅｘａｘ｜は、光軸ＡＺを基準とした透過光学系１１０の射出瞳位置から、最もスクリーンＳＣ側のレンズまでの基準光線Ｒの主光線の光路長である。 0.80 <| Pexax | / Tl <15 (4)
Here, | Pexax | is the optical path length of the principal ray of the reference ray R from the exit pupil position of the transmission optical system 110 with respect to the optical axis AZ to the lens closest to the screen SC.
　条件式（４）は、透過光学系１１０の光軸ＡＺを基準とした射出瞳位置と全長との好適な範囲を規定している。｜Ｐｅｘａｘ｜／Ｔｌが条件式（４）を満足することで、小型でありながら画像歪みの低減された投写光学系１００とすることが可能である。｜Ｐｅｘａｘ｜／Ｔｌが条件式（４）の上限を超えると、投写光学系１００はテレセントリック光学系に近い構成となる。しかし、像面湾曲を適切に補正すると透過光学系１１０のサイズが大きくなるため、投写光学系１００の小型化に不利となる。反対に、｜Ｐｅｘａｘ｜／Ｔｌが条件式（４）の下限を下回ると、透過光学系１１０からの射出光線が広がり、反射光学系１２０のサイズが大きくなる。そのため、投写光学系１００の小型化に不利となる。 Conditional expression (4) defines a suitable range of the exit pupil position and the total length with reference to the optical axis AZ of the transmission optical system 110. When | Pexax | / Tl satisfies the conditional expression (4), it is possible to obtain a projection optical system 100 that is small in size and reduced in image distortion. When | Pexax | / Tl exceeds the upper limit of the conditional expression (4), the projection optical system 100 has a configuration close to a telecentric optical system. However, if the curvature of field is appropriately corrected, the size of the transmission optical system 110 increases, which is disadvantageous for downsizing the projection optical system 100. On the contrary, when | Pexax | / Tl falls below the lower limit of the conditional expression (4), the emitted light from the transmission optical system 110 spreads, and the size of the reflection optical system 120 increases. This is disadvantageous for downsizing of the projection optical system 100.
　さらに、以下の条件式（４ａ）を満足することで、上記した効果をより奏功することができる。 Furthermore, by satisfying the following conditional expression (4a), the above-described effects can be achieved more effectively.
　０．８５　＜　｜Ｐｅｘａｘ｜／Ｔｌ　＜　１３　・・・（４ａ）
　さらに、以下の条件式（４ｂ）を満足することで、上記した効果をより奏功することができる。 0.85 <| Pexax | / Tl <13 (4a)
Furthermore, when the following conditional expression (4b) is satisfied, the above-described effects can be more effectively achieved.
　０．９０　＜　｜Ｐｅｘａｘ｜／Ｔｌ　＜　１１　・・・（４ｂ）
　さらに、以下の条件式（４ｃ）を満足することで、上記した効果をより奏功することができる。 0.90 <| Pexax | / Tl <11 (4b)
Furthermore, when the following conditional expression (4c) is satisfied, the above-described effects can be more effectively achieved.
　０．９５　＜　｜Ｐｅｘａｘ｜／Ｔｌ　＜　９　・・・（４ｃ）
　本開示に係る投写光学系１００は、以下の条件式（５）を満足することが好ましい。 0.95 <| Pexax | / Tl <9 (4c)
The projection optical system 100 according to the present disclosure preferably satisfies the following conditional expression (5).
　１．０　＜　｜Ｐｉｎａｘ｜／Ｔｌ　＜　５０　・・・（５）
　ここで、｜Ｐｉｎａｘ｜は、光軸ＡＺを基準とした透過光学系１１０の入射瞳位置から、最も縮小側のレンズまでの基準光線Ｒの主光線の光路長である。 1.0 <| Pinax | / Tl <50 (5)
Here, | Pinax | is the optical path length of the principal ray of the reference ray R from the entrance pupil position of the transmission optical system 110 with respect to the optical axis AZ to the lens on the most reduction side.
　条件式（５）は、透過光学系１１０の光軸ＡＺを基準とした入射瞳位置と全長との好適な範囲を規定している。｜Ｐｉｎａｘ｜／Ｔｌが条件式（５）の下限を下回ると、像面から入射する光線角度が大きくなり、表示素子としてＤＭＤを使用した場合の光量ロスが顕著となる。そのため、スクリーンＳＣ上の照度分布均一性を維持することが困難となる。反対に、｜Ｐｉｎａｘ｜／Ｔｌが条件式（５）の上限を超えると、投写光学系１００に対する透過光学系１１０の全長が短くなり、像面湾曲を良好に維持することが困難となる。 Conditional expression (5) defines a suitable range of the entrance pupil position and the total length with reference to the optical axis AZ of the transmission optical system 110. When | Pinax | / Tl is less than the lower limit of the conditional expression (5), the angle of light incident from the image plane becomes large, and the light amount loss becomes significant when DMD is used as a display element. Therefore, it becomes difficult to maintain the illuminance distribution uniformity on the screen SC. On the other hand, if | Pinax | / Tl exceeds the upper limit of the conditional expression (5), the total length of the transmission optical system 110 with respect to the projection optical system 100 becomes short, and it becomes difficult to maintain the field curvature well.
　さらに、以下の条件式（５ａ）を満足することで、上記した効果をより奏功することができる。 Furthermore, by satisfying the following conditional expression (5a), the above-described effects can be achieved more effectively.
　１．２　＜　｜Ｐｉｎａｘ｜／Ｔｌ　＜　４６　・・・（５ａ）
　さらに、以下の条件式（５ｂ）を満足することで、上記した効果をより奏功することができる。 1.2 <| Pinax | / Tl <46 (5a)
Furthermore, when the following conditional expression (5b) is satisfied, the above-described effects can be more effectively achieved.
　１．４　＜　｜Ｐｉｎａｘ｜／Ｔｌ　＜　４２　・・・（５ｂ）
　さらに、以下の条件式（５ｃ）を満足することで、上記した効果をより奏功することができる。 1.4 <| Pinax | / Tl <42 (5b)
Furthermore, when the following conditional expression (5c) is satisfied, the above-described effects can be more effectively achieved.
　１．６　＜　｜Ｐｉｎａｘ｜／Ｔｌ　＜　３９　・・・（５ｃ）
　表１から表５に、数値実施例１から５に係る投射光学系について求めた各条件式の対応値を示す。なお、各表に示されるように、｜Ｐｅｘ｜、｜Ｐｉｎ｜およびＲｆについては、Ｘ方向に沿った距離と、Ｙ方向に沿った距離とが異なる。例えば、数値実施例１において、｜Ｐｅｘ｜については、Ｙ方向に沿った距離が、最大の距離である。 1.6 <| Pinax | / Tl <39 (5c)
Tables 1 to 5 show corresponding values of the conditional expressions obtained for the projection optical systems according to Numerical Examples 1 to 5. As shown in each table, for | Pex |, | Pin |, and Rf, the distance along the X direction is different from the distance along the Y direction. For example, in Numerical Example 1, for | Pex |, the distance along the Y direction is the maximum distance.
　（条件式の対応値） (Corresponding value of conditional expression)
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　以下、上記実施の形態に係る投写光学系を具体的に実施した数値実施例を説明する。なお、各数値実施例において、データ中の長さの単位はすべて「ｍｍ」であり、画角の単位はすべて「°」である。また、各数値実施例において、ｒは曲率半径、ｄは面間隔、ｎｄはｄ線に対する屈折率、ｖｄはｄ線に対するアッベ数である。また、各数値実施例において、＊印を付した面は非球面または自由曲面であり、非球面形状は次式で定義している。 Hereinafter, numerical examples in which the projection optical system according to the above embodiment is specifically implemented will be described. In each numerical example, the unit of length in the data is “mm”, and the unit of angle of view is “°”. In each numerical example, r is a radius of curvature, d is a surface interval, nd is a refractive index with respect to the d line, and vd is an Abbe number with respect to the d line. In each numerical example, the surface marked with * is an aspherical surface or a free-form surface, and the aspherical shape is defined by the following equation.
Figure JPOXMLDOC01-appb-M000006
Figure JPOXMLDOC01-appb-M000006
　ここで、
　ｚ：ｚ軸に平行な面のサグ量、
　ｒ：半径方向の距離（＝√（ｘ２＋ｙ２））、
　ｃ：面頂点における曲率、
　ｋ：コーニック係数、
　である。 here,
z: sag amount of the plane parallel to the z-axis,
r: radial distance (= √ (x 2 + y 2 )),
c: curvature at the surface vertex,
k: conic coefficient,
It is.
　なお、非球面係数は、円錐常数Ｋ以外は０でない係数のみ記す。また、レンズ群データにおいて、レンズ構成長は、第１面から終面までの間隔であり、前側主点位置は、第１面からの距離であり、後側主点位置は、第１面からの距離である。また、ズームデータにおいて、８０インチは広角を意味し、１００インチは中間を意味し、５０インチは望遠を意味している。 As for the aspheric coefficient, only coefficients other than the conic constant K are described. In the lens group data, the lens constituent length is the distance from the first surface to the end surface, the front principal point position is the distance from the first surface, and the rear principal point position is from the first surface. Is the distance. In the zoom data, 80 inches means a wide angle, 100 inches means a middle, and 50 inches means telephoto.
　なお、図３は、数値実施例１における透過光学系１１０の構成図である。図４は、数値実施例２における透過光学系１１０の構成図である。図５は、数値実施例３における透過光学系１１０の構成図である。図６は、数値実施例４における透過光学系１１０の構成図である。図７は、数値実施例５における透過光学系１１０の構成図である。 FIG. 3 is a configuration diagram of the transmission optical system 110 in Numerical Example 1. FIG. 4 is a configuration diagram of the transmission optical system 110 in Numerical Example 2. FIG. 5 is a configuration diagram of the transmission optical system 110 in Numerical Example 3. FIG. 6 is a configuration diagram of the transmission optical system 110 in Numerical Example 4. FIG. 7 is a configuration diagram of the transmission optical system 110 in Numerical Example 5.
　（数値実施例１）
　以下の表６から表１１に、数値実施例１の透過光学系１１０の具体的なデータを示す。なお、数値実施例１におけるスローレシオは、０．１７５である。また、投写倍率は１１２．７５から２１７．０６である。また、使用する画像表示素子１３０のサイズは、長辺方向が９．８５６ｍｍ、短辺方向が６．１６２ｍｍである。画像表示素子１３０は、第１レンズ素子Ｌ１のＲ１面頂に対し＋１．２３ｍｍＹ方向へシフトしている。 (Numerical example 1)
Tables 6 to 11 below show specific data of the transmission optical system 110 of Numerical Example 1. In addition, the slow ratio in Numerical Example 1 is 0.175. The projection magnification is 112.75 to 217.06. The size of the image display element 130 to be used is 9.856 mm in the long side direction and 6.162 mm in the short side direction. The image display element 130 is shifted in the +1.23 mm Y direction with respect to the R1 surface apex of the first lens element L1.
　数値実施例１の各光学素子の面データを以下の表６に示す。 Table 6 below shows surface data of each optical element in Numerical Example 1.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　以下、非球面データを表７に示す。 The aspheric data are shown in Table 7 below.
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
　以下、ズームデータを表８に示す。なお、ズーム比は、０．９４８５５である。 The zoom data is shown in Table 8 below. The zoom ratio is 0.94855.
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
　以下、単レンズデータを表９に示す。 The single lens data is shown in Table 9 below.
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
　以下、レンズ群データを表１０に示す。 The lens group data is shown in Table 10 below.
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
　以下、ズームレンズ群倍率を表１１に示す。 The zoom lens group magnification is shown in Table 11 below.
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000012
　（数値実施例２）
　以下の表１２から表１７に、数値実施例２の透過光学系１１０の具体的なデータを示す。なお、数値実施例２におけるスローレシオは、０．１７７である。また、投写倍率は１１２．７６から２１７．１１である。また、使用する画像表示素子１３０のサイズは、長辺方向が９．８５６ｍｍ、短辺方向が６．１６２ｍｍである。画像表示素子１３０は、第１レンズ素子Ｌ１のＲ１面頂に対し＋１．２３ｍｍＹ方向へシフトしている。 (Numerical example 2)
Tables 12 to 17 below show specific data of the transmission optical system 110 of Numerical Example 2. In addition, the slow ratio in Numerical Example 2 is 0.177. The projection magnification is 112.76 to 217.11. The size of the image display element 130 to be used is 9.856 mm in the long side direction and 6.162 mm in the short side direction. The image display element 130 is shifted in the +1.23 mm Y direction with respect to the R1 surface apex of the first lens element L1.
　数値実施例２の各光学素子の面データを以下の表１２に示す。 Table 12 below shows surface data of each optical element in Numerical Example 2.
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000013
　以下、非球面データを表１３に示す。 Hereinafter, aspherical data are shown in Table 13.
Figure JPOXMLDOC01-appb-T000014
Figure JPOXMLDOC01-appb-T000014
　以下、ズームデータを表１４に示す。なお、ズーム比は、０．９２１４３である。 The zoom data is shown in Table 14 below. The zoom ratio is 0.92143.
Figure JPOXMLDOC01-appb-T000015
Figure JPOXMLDOC01-appb-T000015
　以下、単レンズデータを表１５に示す。 Hereinafter, single lens data is shown in Table 15.
Figure JPOXMLDOC01-appb-T000016
Figure JPOXMLDOC01-appb-T000016
　以下、レンズ群データを表１６に示す。 The lens group data is shown in Table 16 below.
Figure JPOXMLDOC01-appb-T000017
Figure JPOXMLDOC01-appb-T000017
　以下、ズームレンズ群倍率を表１７に示す。 The zoom lens group magnification is shown in Table 17 below.
Figure JPOXMLDOC01-appb-T000018
Figure JPOXMLDOC01-appb-T000018
　（数値実施例３）
　以下の表１８から表２３に、数値実施例３の透過光学系１１０の具体的なデータを示す。なお、数値実施例３におけるスローレシオは、０．１６６である。また、投写倍率は１１２．９０から２１７．１８倍である。また、使用する画像表示素子１３０のサイズは、長辺方向が９．８５６ｍｍ、短辺方向が６．１６２ｍｍである。画像表示素子１３０は、第１レンズ素子Ｌ１のＲ１面頂に対し＋１．３０ｍｍＹ方向へシフトしている。 (Numerical Example 3)
Tables 18 to 23 below show specific data of the transmission optical system 110 of Numerical Example 3. In addition, the slow ratio in Numerical Example 3 is 0.166. The projection magnification is 112.90 to 217.18 times. The size of the image display element 130 to be used is 9.856 mm in the long side direction and 6.162 mm in the short side direction. The image display element 130 is shifted in the +1.30 mm Y direction with respect to the top of the R1 surface of the first lens element L1.
　数値実施例３の各光学素子の面データを以下の表１８に示す。 Table 18 below shows surface data of each optical element in Numerical Example 3.
Figure JPOXMLDOC01-appb-T000019
Figure JPOXMLDOC01-appb-T000019
　以下、非球面データを表１９に示す。 Hereinafter, aspherical data are shown in Table 19.
Figure JPOXMLDOC01-appb-T000020
Figure JPOXMLDOC01-appb-T000020
　以下、ズームデータを表２０に示す。なお、ズーム比は、０．９９４１４である。 The zoom data is shown in Table 20 below. The zoom ratio is 0.99414.
Figure JPOXMLDOC01-appb-T000021
Figure JPOXMLDOC01-appb-T000021
　以下、単レンズデータを表２１に示す。 Hereinafter, single lens data is shown in Table 21.
Figure JPOXMLDOC01-appb-T000022
Figure JPOXMLDOC01-appb-T000022
　以下、レンズ群データを表２２に示す。 The lens group data is shown in Table 22 below.
Figure JPOXMLDOC01-appb-T000023
Figure JPOXMLDOC01-appb-T000023
　以下、ズームレンズ群倍率を表２３に示す。 Hereinafter, zoom lens group magnifications are shown in Table 23.
Figure JPOXMLDOC01-appb-T000024
Figure JPOXMLDOC01-appb-T000024
　（数値実施例４）
　以下の表２４から表２９に、数値実施例４の透過光学系１１０の具体的なデータを示す。なお、数値実施例４におけるスローレシオは、０．１９４である。また、投写倍率は１１２．９２から２１６．９７倍である。また、使用する画像表示素子１３０のサイズは、長辺方向が９．８５６ｍｍ、短辺方向が６．１６２ｍｍである。画像表示素子１３０は、第１レンズ素子Ｌ１のＲ１面頂に対し＋０．７４ｍｍＹ方向へシフトしている。 (Numerical example 4)
Tables 24 to 29 below show specific data of the transmission optical system 110 according to Numerical Example 4. In addition, the slow ratio in Numerical Example 4 is 0.194. The projection magnification is 112.92 to 216.97 times. The size of the image display element 130 to be used is 9.856 mm in the long side direction and 6.162 mm in the short side direction. The image display element 130 is shifted in the +0.74 mm Y direction with respect to the R1 surface apex of the first lens element L1.
　数値実施例４の各光学素子の面データを以下の表２４に示す。 Table 24 below shows surface data of each optical element in Numerical Example 4.
Figure JPOXMLDOC01-appb-T000025
Figure JPOXMLDOC01-appb-T000025
　以下、非球面データを表２５に示す。 Hereinafter, Table 25 shows the aspheric data.
Figure JPOXMLDOC01-appb-T000026
Figure JPOXMLDOC01-appb-T000026
　以下、ズームデータを表２６に示す。なお、ズーム比は、１．００３２４である。 The zoom data is shown in Table 26 below. The zoom ratio is 1.003324.
Figure JPOXMLDOC01-appb-T000027
Figure JPOXMLDOC01-appb-T000027
　以下、単レンズデータを表２７に示す。 Hereinafter, Table 27 shows single lens data.
Figure JPOXMLDOC01-appb-T000028
Figure JPOXMLDOC01-appb-T000028
　以下、レンズ群データを表２８に示す。 The lens group data is shown in Table 28 below.
Figure JPOXMLDOC01-appb-T000029
Figure JPOXMLDOC01-appb-T000029
　以下、ズームレンズ群倍率を表２９に示す。 Hereinafter, zoom lens group magnifications are shown in Table 29.
Figure JPOXMLDOC01-appb-T000030
Figure JPOXMLDOC01-appb-T000030
　（数値実施例５）
　以下の表３０から表３５に、数値実施例５の透過光学系１１０の具体的なデータを示す。なお、数値実施例５におけるスローレシオは、０．１６４である。また、投写倍率は１１２．８５から２１７．０６倍である。また、使用する画像表示素子１３０のサイズは、長辺方向が９．８５６ｍｍ、短辺方向が６．１６２ｍｍである。画像表示素子１３０は、第１レンズ素子Ｌ１のＲ１面頂に対し＋１．２４ｍｍＹ方向へシフトしている。 (Numerical example 5)
Tables 30 to 35 below show specific data of the transmission optical system 110 of Numerical Example 5. In addition, the slow ratio in Numerical Example 5 is 0.164. The projection magnification is 112.85 to 217.06 times. The size of the image display element 130 to be used is 9.856 mm in the long side direction and 6.162 mm in the short side direction. The image display element 130 is shifted in the +1.24 mm Y direction with respect to the R1 surface apex of the first lens element L1.
　数値実施例５の各光学素子の面データを以下の表３０に示す。 Table 30 below shows surface data of each optical element in Numerical Example 5.
Figure JPOXMLDOC01-appb-T000031
Figure JPOXMLDOC01-appb-T000031
　以下、非球面データを表３１に示す。 The aspheric data are shown in Table 31 below.
Figure JPOXMLDOC01-appb-T000032
Figure JPOXMLDOC01-appb-T000032
　以下、ズームデータを表３２に示す。なお、ズーム比は、０．９９０４６である。 The zoom data is shown in Table 32 below. The zoom ratio is 0.99046.
Figure JPOXMLDOC01-appb-T000033
Figure JPOXMLDOC01-appb-T000033
　以下、単レンズデータを表３３に示す。 Hereinafter, single lens data is shown in Table 33.
Figure JPOXMLDOC01-appb-T000034
Figure JPOXMLDOC01-appb-T000034
　以下、レンズ群データを表３４に示す。 The lens group data is shown in Table 34 below.
Figure JPOXMLDOC01-appb-T000035
Figure JPOXMLDOC01-appb-T000035
　以下、ズームレンズ群倍率を表３５に示す。 Hereinafter, zoom lens group magnifications are shown in Table 35.
Figure JPOXMLDOC01-appb-T000036
Figure JPOXMLDOC01-appb-T000036
　（他の実施の形態）
　以上のように、本出願において開示する技術の例示として、実施の形態を説明した。しかしながら、本開示における技術は、これに限定されず、変更、置き換え、付加、省略などを行った実施の形態にも適用できる。また、上記実施の形態で説明した各構成要素を組み合わせて、新たな実施の形態とすることも可能である。 (Other embodiments)
As described above, the embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can also be applied to embodiments that have been changed, replaced, added, omitted, and the like. Moreover, it is also possible to combine each component demonstrated in the said embodiment and it can also be set as a new embodiment.
　なお、上述の実施の形態は、本開示における技術を例示するためのものであるから、請求の範囲またはその均等の範囲において種々の変更、置き換え、付加、省略などを行うことができる。 Note that the above-described embodiment is for illustrating the technique in the present disclosure, and therefore various modifications, replacements, additions, omissions, and the like can be made within the scope of the claims or an equivalent scope thereof.
　本開示は、画像表示素子に表示された画像を投写するための投写光学系に適用可能である。具体的には、プロジェクターやヘッドアップディスプレイなどに、本開示は適用可能である。 The present disclosure can be applied to a projection optical system for projecting an image displayed on an image display element. Specifically, the present disclosure is applicable to a projector, a head-up display, and the like.
　１　画像投写システム
　１０　画像投写装置
　１００　投写光学系
　１１０　透過光学系
　１２０　反射光学系
　１２１　第１ミラー（凹面ミラーの一例）
　１２２　第２ミラー（平面ミラーの一例）
　１３０　画像表示素子
　１４０　透過素子
　Ａ　開口絞り
　ＰＢ　プリズム
　ＳＣ　スクリーン（被投射面の一例） DESCRIPTION OF SYMBOLS 1 Image projection system 10 Image projection apparatus 100 Projection optical system 110 Transmission optical system 120 Reflection optical system 121 1st mirror (an example of a concave mirror)
122 Second mirror (an example of a plane mirror)
130 Image display element 140 Transmission element A Aperture stop PB Prism SC Screen (an example of a projection surface)

Claims (19)

  1. 　被投写面に画像を投写するために用いられ、縮小側の像面と前記被投写面側の像面とを共役の関係にする投写光学系であって、
    　開口絞りと、それぞれパワーを有する複数のレンズとを含む透過光学系と、
    　前記透過光学系からの出射光を反射する反射光学系と、を備え、
    　基準光線の主光線は、前記被投写面の最も前記投写光学系側に投写される光線のうち前記開口絞りの中心を通る光線であり、
    　前記投写光学系は、前記縮小側の像面と共役な中間像面を前記透過光学系と前記反射光学系の間に有し、
    　前記投写光学系は、以下の条件式（１）を満足する、投写光学系。
    　０．７０　＜　｜Ｐｅｘ｜／Ｔｌ　＜　４０　・・・（１）
    　ここで、
    　Ｔｌは、前記複数のレンズのうち最も前記縮小側のレンズから、前記複数のレンズのうち最も前記被投写面側のレンズまでの距離であり、
    　｜Ｐｅｘ｜は、前記基準光線の主光線を基準とした前記透過光学系の射出瞳位置から、前記複数のレンズのうち最も前記被投写面側のレンズまでの前記基準光線の主光線の光路長のうち最大の距離である。     A projection optical system that is used to project an image on a projection surface and that has a conjugate relationship between a reduction-side image plane and the projection-plane-side image plane;
    A transmission optical system including an aperture stop and a plurality of lenses each having power;
    A reflection optical system that reflects light emitted from the transmission optical system, and
    The principal ray of the reference ray is a ray that passes through the center of the aperture stop among the rays that are projected closest to the projection optical system of the projection surface,
    The projection optical system has an intermediate image plane conjugate with the reduction-side image plane between the transmission optical system and the reflection optical system,
    The projection optical system satisfies the following conditional expression (1).
    0.70 <| Pex | / Tl <40 (1)
    here,
    Tl is a distance from the lens on the most reduced side among the plurality of lenses to the lens on the most projected surface side among the plurality of lenses;
    | Pex | is the optical path length of the principal ray of the reference ray from the exit pupil position of the transmission optical system with respect to the principal ray of the reference ray to the lens closest to the projection surface among the plurality of lenses. Is the maximum distance.
  2. 　前記投写光学系は、以下の条件式（２）を満足する、請求項１に記載の投写光学系。
    　１．００　＜　｜Ｐｉｎ｜／Ｔｌ　＜　５０　・・・（２）
    　ここで、
    　｜Ｐｉｎ｜は、前記基準光線の主光線を基準とした前記透過光学系の入射瞳位置から、前記複数のレンズのうち最も前記縮小側のレンズまでの前記基準光線の主光線の光路長のうち最大の距離である。     The projection optical system according to claim 1, wherein the projection optical system satisfies the following conditional expression (2).
    1.00 <| Pin | / Tl <50 (2)
    here,
    | Pin | is the optical path length of the principal ray of the reference ray from the entrance pupil position of the transmission optical system with respect to the principal ray of the reference ray to the lens on the most reduced side among the plurality of lenses It is the maximum distance.
  3. 　前記投写光学系は、以下の条件式（３）を満足する、請求項１または２に記載の投写光学系。
    　０．０５０　＜　Ｔｌ／Ｒｆ　＜　５．０　・・・（３）
    　ここで、
    　Ｒｆは、前記基準光線の主光線を基準とした前記透過光学系の最大の焦点距離である。     The projection optical system according to claim 1, wherein the projection optical system satisfies the following conditional expression (3).
    0.050 <Tl / Rf <5.0 (3)
    here,
    Rf is the maximum focal length of the transmission optical system based on the principal ray of the reference ray.
  4. 　前記複数のレンズは、前記透過光学系の光軸として、同一の回転対称軸を有する、
    請求項１から３のいずれかに記載の投写光学系。     The plurality of lenses have the same rotational symmetry axis as the optical axis of the transmission optical system.
    The projection optical system according to claim 1.
  5. 　前記投写光学系は、以下の条件式（４）を満足する、請求項４に記載の投写光学系。
    　０．８０　＜　｜Ｐｅｘａｘ｜／Ｔｌ　＜　１５　・・・（４）
    　ここで、
    　｜Ｐｅｘａｘ｜は、前記光軸を基準とした前記透過光学系の射出瞳位置から、前記複数のレンズのうち最も前記被投写面側のレンズまでの前記基準光線の主光線の光路長である。     The projection optical system according to claim 4, wherein the projection optical system satisfies the following conditional expression (4).
    0.80 <| Pexax | / Tl <15 (4)
    here,
    | Pexax | is the optical path length of the principal ray of the reference ray from the exit pupil position of the transmission optical system with respect to the optical axis to the lens closest to the projection surface among the plurality of lenses.
  6. 　前記投写光学系は、以下の条件式（５）を満足する、請求項４または５に記載の投写光学系。
    　１．０　＜　｜Ｐｉｎａｘ｜／Ｔｌ　＜　５０　・・・（５）
    　ここで、
    　｜Ｐｉｎａｘ｜は、前記光軸を基準とした前記透過光学系の入射瞳位置から、前記複数のレンズのうち最も前記縮小側のレンズまでの前記基準光線の主光線の光路長である。     The projection optical system according to claim 4, wherein the projection optical system satisfies the following conditional expression (5).
    1.0 <| Pinax | / Tl <50 (5)
    here,
    | Pinax | is the optical path length of the principal ray of the reference ray from the entrance pupil position of the transmission optical system with respect to the optical axis to the lens on the most reduction side among the plurality of lenses.
  7. 　前記基準光線の主光線は、前記縮小側の像面から前記開口絞りまでの間で前記光軸と交わらない、
    請求項４から６のいずれかに記載の投写光学系。     The principal ray of the reference ray does not intersect the optical axis between the reduction-side image plane and the aperture stop,
    The projection optical system according to claim 4.
  8. 　前記複数のレンズは、前記開口絞りと前記縮小側の像面との間に配置された正レンズを含み、
    　前記正レンズは、前記複数のレンズのうちで最も強い正のパワーを有する、
    請求項１から７のいずれかに記載の投写光学系。     The plurality of lenses includes a positive lens disposed between the aperture stop and the reduction-side image plane,
    The positive lens has the strongest positive power among the plurality of lenses.
    The projection optical system according to claim 1.
  9. 　前記複数のレンズは、前記開口絞りと前記縮小側の像面との間に配置された負レンズを含み、
    　前記負レンズは、前記複数のレンズのうちで最も強い負のパワーを有する、
    請求項１から８のいずれかに記載の投写光学系。     The plurality of lenses includes a negative lens disposed between the aperture stop and the reduction-side image plane,
    The negative lens has the strongest negative power among the plurality of lenses.
    The projection optical system according to claim 1.
  10. 　前記複数のレンズは、前記開口絞りと前記縮小側の像面との間に配置された正レンズと負レンズとを含み、
    　前記正レンズは、前記複数のレンズのうちで最も強い正のパワーを有し、
    　前記負レンズは、前記複数のレンズのうちで最も強い負のパワーを有し、
    　前記正レンズと、前記負レンズとは、隣接して配置される、
    請求項１から７のいずれかに記載の投写光学系。     The plurality of lenses includes a positive lens and a negative lens disposed between the aperture stop and the reduction-side image plane,
    The positive lens has the strongest positive power among the plurality of lenses,
    The negative lens has the strongest negative power among the plurality of lenses,
    The positive lens and the negative lens are disposed adjacent to each other.
    The projection optical system according to claim 1.
  11. 　前記正レンズと、前記負レンズとは、接合されている、
    請求項１０に記載の投写光学系。     The positive lens and the negative lens are cemented,
    The projection optical system according to claim 10.
  12. 　前記反射光学系は、凹面ミラーを有する、
    請求項１から１１のいずれかに記載の投写光学系。     The reflective optical system has a concave mirror,
    The projection optical system according to claim 1.
  13. 　前記反射光学系は、平面ミラーを有する、
    請求項１から１２のいずれかに記載の投写光学系。     The reflective optical system has a plane mirror,
    The projection optical system according to claim 1.
  14. 　前記反射光学系は、凹面ミラーと平面ミラーとを含み、
    　前記凹面ミラーは、前記透過光学系からの出射光を反射し、
    　前記平面ミラーは、前記凹面ミラーからが反射した光を反射する、
    請求項１から１１のいずれかに記載の投写光学系。     The reflective optical system includes a concave mirror and a plane mirror,
    The concave mirror reflects light emitted from the transmission optical system;
    The plane mirror reflects light reflected from the concave mirror;
    The projection optical system according to claim 1.
  15. 　前記凹面ミラーの反射面と、前記平面ミラーの反射面とは、互いに対面する、
    請求項１４に記載の投写光学系。     The reflecting surface of the concave mirror and the reflecting surface of the flat mirror face each other,
    The projection optical system according to claim 14.
  16. 　前記複数のレンズは、前記開口絞りと前記被投写面との間に配置された負のメニスカスレンズを含み、
    　前記負のメニスカスレンズの凸面は、前記被投写面を向いている、
    請求項１から１５のいずれかに記載の投写光学系。     The plurality of lenses includes a negative meniscus lens disposed between the aperture stop and the projection surface,
    The convex surface of the negative meniscus lens faces the projection surface.
    The projection optical system according to claim 1.
  17. 　請求項１から１６のいずれかに記載の投写光学系と、
    　前記画像を形成し、前記縮小側の像面として前記画像の表示面を有する画像形成素子とを備える、画像投写装置。     A projection optical system according to any one of claims 1 to 16,
    An image projection apparatus comprising: an image forming element that forms the image and has a display surface of the image as an image surface on the reduction side.
  18. 　請求項１７に記載の画像投写装置と、
    　前記被投写面とを備える、画像投写システム。     An image projection device according to claim 17,
    An image projection system comprising the projection surface.
  19. 　前記被投写面は、曲率を有する、
    　請求項１８に記載の画像投写システム。     The projection surface has a curvature;
    The image projection system according to claim 18.
PCT/JP2017/044305 2017-03-29 2017-12-11 Projection optical system, image projection device, and image projection system WO2018179607A1 (en)

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WO2006043666A1 (en) * 2004-10-21 2006-04-27 Sony Corporation Projection optical system and projection type image display device
JP2013064816A (en) * 2011-09-16 2013-04-11 Ricoh Co Ltd Image display device
JP2014170127A (en) * 2013-03-04 2014-09-18 Ricoh Co Ltd Projection optical system and image display device
JP2014170186A (en) * 2013-03-05 2014-09-18 Ricoh Co Ltd Projection optical system and projector
WO2018008199A1 (en) * 2016-07-04 2018-01-11 パナソニックＩｐマネジメント株式会社 Projection optical system and image projection device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006043666A1 (en) * 2004-10-21 2006-04-27 Sony Corporation Projection optical system and projection type image display device
JP2013064816A (en) * 2011-09-16 2013-04-11 Ricoh Co Ltd Image display device
JP2014170127A (en) * 2013-03-04 2014-09-18 Ricoh Co Ltd Projection optical system and image display device
JP2014170186A (en) * 2013-03-05 2014-09-18 Ricoh Co Ltd Projection optical system and projector
WO2018008199A1 (en) * 2016-07-04 2018-01-11 パナソニックＩｐマネジメント株式会社 Projection optical system and image projection device

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