WO2018193755A1

WO2018193755A1 - Planar illumination device

Info

Publication number: WO2018193755A1
Application number: PCT/JP2018/009794
Authority: WO
Inventors: 山田　敦; 健太大石
Original assignee: ミネベアミツミ株式会社
Priority date: 2017-04-21
Filing date: 2018-03-13
Publication date: 2018-10-25

Abstract

A planar illumination device (1) according to an embodiment of the present invention is provided with a light source and a light guide plate (5). The light source emits light in a prescribed direction (B). The light guide plate (5) has a side surface (5c), an emission surface (5d) that is one main surface, and a back surface (5e) that is the other main surface. A prism (5f) is formed on the back surface (5e), and light incident on the side surface (5c) from the light source is emitted from the emission surface (5d). The prism (5f) has, if being cut in parallel to the prescribed direction (B), a first region (5f1) that is roughly parallel to the emission surface (5d) and a second region (5f2) that is inclined with respect to the emission surface (5d). The first region (5f1) and the second region (5f2) extend in a direction oblique to the prescribed direction (B).

Description

Surface lighting device

The present invention relates to a planar illumination device.

2. Description of the Related Art Conventionally, a planar lighting device for in-vehicle lighting that illuminates a driver's seat or a passenger seat in an automobile has been provided. In addition, a planar illumination device that further has translucency and is visible through such a planar illumination device has been recently demanded.

JP 2010-105563 A

However, it has been difficult to achieve high light distribution while maintaining translucency in a planar illumination device having translucency. Therefore, not only the driver's seat and the passenger's seat, but also the driver and the passenger's seat are irradiated with light, and the driver and the passenger's seat may feel dazzled.

This invention is made | formed in view of the above, Comprising: It aims at providing the planar illuminating device which can make translucency and high light distribution compatible.

In order to solve the above-described problems and achieve the object, a planar illumination device according to an aspect of the present invention includes a light source and a light guide plate. The light source emits light in a predetermined direction. The light guide plate has a side surface, an emission surface that is one main surface, and a back surface that is the other main surface, a prism is formed on the back surface, and light incident on the side surface from the light source is The light exits from the exit surface. The prism includes a first region that is substantially parallel to the emission surface and a second region that is inclined with respect to the emission surface when the prism is cut parallel to the predetermined direction. The region and the second region extend obliquely with respect to the predetermined direction.

According to one embodiment of the present invention, it is possible to achieve both translucency and high light distribution.

FIG. 1A is a front view of the planar illumination device according to the embodiment. 1B is a cross-sectional view taken along line AA in FIG. 1A. FIG. 2A is an enlarged view of a region D in FIG. 1A. FIG. 2B is an enlarged view of region E in FIG. 1A. 2C is a cross-sectional view taken along line FF in FIG. 2A. FIG. 3A is a diagram for explaining the light bar according to the embodiment. FIG. 3B is an enlarged view of the light bar according to the embodiment. FIG. 3C is an enlarged view of region H in FIG. 3A. FIG. 3D is an enlarged view of region J in FIG. 3A. 3E is a cross-sectional view taken along line KK in FIG. 3A. FIG. 4A is an enlarged view of a central portion in the longitudinal direction of the prism sheet according to the embodiment. FIG. 4B is an enlarged view of the vicinity of the end in the longitudinal direction of the prism sheet according to the embodiment. FIG. 5A is a view for explaining the visual field control film according to the embodiment. FIG. 5B is a diagram for describing another example of the visual field control film according to the embodiment. FIG. 6A is a front view of the planar illumination device according to the first modification of the embodiment. FIG. 6B is an enlarged view of region M in FIG. 6A. FIG. 7A is an enlarged view of a first light guide unit according to Modification 2 of the embodiment. FIG. 7B is an enlarged view of the second light guide unit according to the second modification of the embodiment. FIG. 8 is a cross-sectional view of a planar illumination device according to Modification 3 of the embodiment. FIG. 9 is a diagram for explaining a visual field control film according to Modification 3 of the embodiment. FIG. 10A is a diagram for explaining light distribution in the planar illumination device of the reference example. FIG. 10B is a diagram for describing light distribution in the planar illumination device according to the modification 3 of the embodiment. FIG. 11 is a cross-sectional view of a planar illumination device according to Modification 4 of the embodiment. FIG. 12 is a diagram illustrating a light distribution in the planar lighting device of the reference example. FIG. 13 is a diagram for explaining the azimuth angle in the light distribution shown in FIG. FIG. 14 is a diagram for explaining polar angles in the light distribution shown in FIG. FIG. 15 is a diagram illustrating a cross section of the light distribution in the embodiment, the third modification, the fourth modification, and the reference example.

Hereinafter, the planar lighting device according to the embodiment will be described with reference to the drawings. Note that the application of the planar lighting device is not limited by the embodiment described below. It should be noted that the drawings are schematic, and the relationship between the dimensions of each element, the ratio of each element, and the like may differ from the actual situation. Furthermore, there are cases in which parts having different dimensional relationships and ratios are included between the drawings.

(Embodiment)
First, the outline | summary of the planar illuminating device 1 which concerns on embodiment is demonstrated, referring FIG. 1A and FIG. 1B. FIG. 1A is a front view of the planar lighting device 1 according to the embodiment, and FIG. 1B is a cross-sectional view taken along line AA in FIG. 1A.

As shown in FIG. 1A, the planar illumination device 1 includes a housing frame 2,

linear light sources

3A and 3B, a visual field control film 4, and a light guide plate 5. The planar illumination device 1 is used, for example, as an in-vehicle illumination lamp that illuminates the hands of a driver's seat and a passenger seat of an automobile.

The housing frame 2 holds and stores the

linear light sources

3A and 3B, the visual field control film 4, and the light guide plate 5. The housing frame 2 is made of, for example, synthetic resin or metal. As shown in FIG. 1B, the housing frame 2 has an opening 2a formed on the main surface 5d side of the light guide plate 5 and an opening 2b formed on the main surface 5e side of the light guide plate 5. The light guide plate 5 is exposed from the

openings

2a and 2b. In FIG. 1A, for convenience of explanation, illustration of a portion on the positive side in the Z-axis direction of the housing frame 2 at a position where the

linear light sources

3A and 3B and the visual field control film 4 are disposed is omitted.

As shown in FIGS. 1A and 1B, the linear light source 3A is, for example, a light source that emits light emitted toward the passenger seat in the vehicle (lower left side in FIG. 1A). It is a light source which emits the light radiate | emitted by the driver's seat side (FIG. 1A lower right side). The linear light sources 3 A and 3 B include a pair of FPC (Flexible Printed Circuits) 10, a pair of LEDs (Light Emitting Diode) 11, a pair of light bars 12, and one prism sheet 13.

The FPC 10 is a board on which the LEDs 11 are mounted. The FPC 10 has a mounting surface configured such that the LED 11 can be mounted, and a surface opposite to the light emitting surface 11a of the LED 11 is bonded to the mounting surface.

A drive circuit (not shown) is connected to each of the pair of FPCs 10. Then, the LED 11 is driven by the driving circuit via the FPC 10, and the corresponding linear

light sources

3A and 3B are turned on.

LED 11 is a point light source. The LED 11 has a light emitting surface 11 a that emits light, and is disposed on the light incident surface 12 a side of the light bar 12 in a state where the light emitting surface 11 a faces the light incident surface 12 a of the light bar 12. The LED 11 emits light from the light emitting surface 11 a toward the light incident surface 12 a of the light bar 12.

Further, as described above, the surface of the LED 11 opposite to the light emitting surface 11a is joined to the FPC 10. That is, the LED 11 is a top view type LED in which the mounted FPC 10 is substantially parallel to the light emitting surface 11a. The LED 11 is not limited to the top view type LED, and may be a side view type LED in which the mounted FPC 10 is orthogonal to the light emitting surface 11a.

The light bar 12 converts light incident from the LED 11, which is a point light source, into linear light and emits it toward the prism sheet 13. The light bar 12 is made of a transparent material (for example, polycarbonate resin), is formed in a rod shape, and has a light incident surface 12a, a light exit surface 12b, and a light exit surface 12c opposite to the light exit surface 12b. .

The light incident surface 12a is one end surface of the light bar 12, and the light emitted from the LED 11 is incident thereon. The light exit surface 12b is a surface substantially perpendicular to the light entrance surface 12a and emits incident light. A plurality of prisms 12j (see FIG. 3E) are formed side by side on the light exit surface 12b. The light exit surface 12c is a surface opposite to the light exit surface 12b, and a plurality of prisms 12g (see FIG. 3C) are formed side by side. Details of the light bar 12 will be described later.

The prism sheet 13 controls the light distribution. The prism sheet 13 is disposed between the light exit surface 12 b of the light bar 12 and the light incident surface 4 a of the visual field control film 4. The prism sheet 13 has a light incident surface 13a that faces the light output surface 12b of the light bar 12, and a light output surface 13b opposite to the light incident surface 13a.

A plurality of prisms 13d (see FIG. 4A) are formed side by side on the light incident surface 13a. A convex lens 13e (see FIG. 4A) is formed side by side on the light exit surface 13b. The details of the prism sheet 13 will be described later.

The linear light sources 3 A and 3 B described so far are in a predetermined direction B (Y-axis negative direction in the drawing) from the light exit surface 13 b of the prism sheet 13 to the side surface 5 c of the light guide plate 5 through the visual field control film 4. A linear light is emitted. Thus, planar light can be emitted from the light guide plate 5 by using the

linear light sources

3A and 3B that emit light linearly.

The visual field control film 4 controls the light distribution angle. The visual field control film 4 is disposed between the light exit surface 13 b of the prism sheet 13 and the side surface 5 c of the light guide plate 5. The field-of-view control film 4 has a light incident surface 4a that faces the light output surface 13b of the prism sheet 13, and a light output surface 4b opposite to the light incident surface 4a. The details of the visual field control film 4 will be described later.

The light guide plate 5 is formed in a rectangular shape when viewed from above, and the first light guide portion 5a into which the light emitted from the linear light source 3A enters and the light emitted from the linear light source 3B enter. And a second light guide 5b. The planar illumination device 1 according to the embodiment is formed symmetrically about a center C shown in FIG. 1A as an axis, and the light guide plate 5 and the first light guide unit 5a are connected to the first C light guide 5a with the center C as a boundary. 2 light guides 5b.

Further, as shown in FIG. 1B, the light guide plate 5 has a side surface 5c facing the visual field control film 4, a main surface 5d, and a main surface 5e opposite to the main surface 5d. The side surface 5c is a strip-shaped surface extending in the X-axis direction. Light traveling in a predetermined direction B is incident on the side surface 5c. Furthermore, when the light guide plate 5 is cut in parallel to the predetermined direction B, the light guide plate 5 has a wedge shape that gradually decreases in thickness in the predetermined direction B. That is, the distance between the main surface 5d and the main surface 5e becomes narrower as the light guide plate 5 is separated from the visual field control film 4.

The

main surfaces

5d and 5e are rectangular surfaces extending along the XY plane. The main surface 5d is an emission surface from which light incident from the side surface 5c is emitted. Therefore, in the following description, the main surface 5d is referred to as “exit surface 5d”. In addition, the main surface 5e on the back side is expressed as “back surface 5e”.

The light guide plate 5 is made of a transparent material (for example, polycarbonate resin) and has a desired translucency. For example, the entire light guide plate 5 is transparent so that an object existing on the back surface 5 e side can be viewed from the exit surface 5 d side through the

openings

2 a and 2 b of the housing frame 2.

As shown in FIG. 1B, the exit surface 5d is disposed substantially parallel to the predetermined direction B. On the other hand, the back surface 5e is inclined from the predetermined direction B. A plurality of prisms 5f (see FIG. 2A) are arranged side by side on the back surface 5e. Next, details of the prism 5f formed on the light guide plate 5 will be described with reference to FIGS. 2A to 2C.

2A is an enlarged view of region D in FIG. 1A, and FIG. 2B is an enlarged view of region E in FIG. 1A. That is, FIG. 2A is an enlarged view of the first light guide portion 5a into which light from the linear light source 3A enters, and FIG. 2B is an enlarged view of the second light guide portion 5b into which light from the linear light source 3B enters. FIG.

2C is a cross-sectional view taken along the line FF in FIG. 2A. Specifically, FIG. 2C is a cross-sectional view when the light guide plate 5 is cut in parallel with a predetermined direction B. Note that FIG. 2C also coincides with the cross section taken along line GG in FIG. 2B.

2C, a plurality of prisms 5f are formed along the predetermined direction B on the back surface 5e of the light guide plate 5. As shown in FIG. The prism 5f has a first region 5f1 and a second region 5f2.

1st area | region 5f1 is substantially planar shape, and when the light-guide plate 5 is cut | disconnected in parallel with the predetermined direction B, as shown to FIG. The second region 5f2 has a substantially planar shape, and is inclined with respect to the emission surface 5d when the light guide plate 5 is cut in parallel with the predetermined direction B. Specifically, the second region 5f2 is inclined in a direction approaching the emission surface 5d as it goes in the predetermined direction B. Also, the second region 5f2 of one prism 5f is formed continuously with the first region 5f1 of the adjacent prism 5f.

As shown in FIG. 2C, the prism 5f having such a cross-sectional shape changes the path of the light irradiated along the predetermined direction B by the

linear light sources

3A and 3B, and emits the light from the emission surface 5d. . Specifically, light is reflected toward the exit surface 5d by the second region 5f2 of the prism 5f. Thus, the light distribution in the Z-axis direction can be controlled by the prism 5f.

Further, when the light guide plate 5 is cut in parallel with the predetermined direction B, the object existing on the back surface 5e side is visually recognized from the exit surface 5d side by making the first region 5f1 and the exit surface 5d substantially parallel. In this case, the physical continuity of the visually recognized object can be increased. That is, the distortion of the visually recognized object can be reduced by making the first region 5f1 and the exit surface 5d substantially parallel. Therefore, the light guide plate 5 has high translucency.

Further, when the first region 5f1 is cut in parallel to the predetermined direction B, the light incident along the predetermined direction B is reflected by the first region 5f1 by making the first region 5f1 substantially parallel to the emission surface 5d. In addition, it is possible to suppress the angle θ of the emitted light 100 from deviating from the predetermined direction B in the Z-axis direction. Therefore, the light distribution in the Z-axis direction in the light guide plate 5 can be accurately controlled.

In the embodiment, as shown in FIGS. 2A and 2B, the first region 5f1 and the second region 5f2 of the prism 5f extend obliquely with respect to the predetermined direction B. Specifically, in the first light guide 5a shown in FIG. 2A, the first region 5f1 and the second region 5f2 are directed from the X-axis negative direction and the Y-axis negative direction to the X-axis positive direction and the Y-axis positive direction. It extends.

2B, the first region 5f1 and the second region 5f2 extend from the X-axis positive direction and the Y-axis negative direction toward the X-axis negative direction and the Y-axis positive direction. .

In this way, by forming the prism 5f so as to extend obliquely with respect to the predetermined direction B, irradiation is performed along the predetermined direction B by the

linear light sources

3A and 3B as shown in FIGS. 2A and 2B. By changing the path of the light to be emitted, the light whose path has been changed can be emitted from the emission surface 5d.

Specifically, as shown in FIG. 2A, the first light guide 5a emits light in the negative X-axis direction and the negative Y-axis direction, and as shown in FIG. 2B, the second light guide 5b The light is emitted in the positive direction of the X axis and in the negative direction of the Y axis. That is, light is emitted from the light guide plate 5 in a direction away from the visual field control film 4 and in a direction approaching both ends where the LEDs 11 are provided. In this way, the light distribution in the X-axis direction can be accurately controlled by the prism 5f.

As described so far, in the planar illumination device 1 according to the embodiment, the light distribution (in the orthogonal direction on the exit surface 5 d of the light guide plate 5) is achieved by the prism 5 f formed on the light guide plate 5. The light distribution in the biaxial direction) can be controlled with high accuracy. Further, as described above, in the planar illumination device 1, the light guide plate 5 has high translucency. That is, according to the embodiment, it is possible to achieve both the light transmitting property and the high light distribution property.

In the embodiment, the light emitted from the light guide plate 5 may be emitted within a range of 40 ° or less in full width at half maximum. Thereby, while irradiating a required area | region (for example, the hand of a driver's seat) enough, it can further suppress that an unnecessary area | region (for example, driver | operator) is irradiated.

In the embodiment, when the light guide plate 5 is cut in parallel to the predetermined direction B, the first region 5f1 and the emission surface 5d do not have to be completely parallel. For example, the first region 5f1 may have an angle of 0 ° or more and 5 ° or less with the emission surface 5d. Further, the first region 5f1 preferably has an angle of 0 ° to 1 ° with the exit surface 5d, and more preferably has an angle of 0 ° to 0.5 ° with the exit surface 5d.

Furthermore, in the embodiment, as shown in FIG. 1B, since the entire light guide plate 5 has a wedge shape in the cross-sectional view of the YZ plane, the light guide plate 5 is cut in a direction different from the predetermined direction B. In this case, the first region 5f1 and the emission surface 5d are not parallel.

In the embodiment, as shown in FIG. 2C, the ratio of the length L2 of the first region 5f1 in the Y-axis direction to the length L1 of the prism 5f in the Y-axis direction (that is, the predetermined direction B) is 60 % Or more and less than 100%. Note that the length L1 is the sum of the length L2 and the length L3 of the second region 5f2 in the Y-axis direction.

In addition, in the cross-sectional view of the YZ plane, the prism angle φ1 formed by the second region 5f2 and the surface 5g parallel to the exit surface 5d is expressed by the following equation (1).
φ1 = {90−asin (sin θ / n)} / 2 (°) (1)

In the above equation (1), the angle θ is an angle (emission angle) formed by the direction 5h perpendicular to the emission surface 5d and the light 100 emitted from the emission surface 5d. N is the refractive index of the light guide plate 5.

In other words, by setting the prism angle φ1 of the prism 5f to a predetermined angle, when the planar illumination device 1 is used as an in-vehicle illumination lamp that illuminates the hands of the driver seat and the passenger seat, a person sitting on the driver or passenger seat It is possible to illuminate only at hand. Thereby, it can suppress that a driver | operator and the person sitting in a passenger seat feel dazzling.

A plurality of lights 100 are emitted in a plurality of directions from the emission surface 5d, and a direction 5h perpendicular to the emission surface 5d and a direction in which the light 100 having the peak luminous intensity among the plurality of lights 100 travels. Is an angle θ.

Next, details of the

linear light sources

3A and 3B and the visual field control film 4 according to the embodiment will be described. First, the light bar 12 of the

linear light sources

3A and 3B will be described with reference to FIGS. 3A to 3E. FIG. 3A is a diagram for explaining the light bar 12 according to the embodiment.

As shown in FIG. 3A, the width (dimension in the Y-axis direction) of the light bar 12 decreases from one end where the light incident surface 12a is provided toward the other end along the longitudinal direction (X-axis direction in the drawing). It has become. The light bar 12 has a root portion 12d including the light incident surface 12a and a tip portion 12e provided away from the light incident surface 12a.

The root portion 12d and the tip portion 12e are formed with different inclinations of the light exit surface 12c. Specifically, as shown in FIG. 3B, the angle φ2 formed between the light exit surface 12c1 provided at the root portion 12d and the surface 12f parallel to the light exit surface 12b is the same as the light exit surface 12c2 provided at the tip portion 12e. The angle φ3 formed with the surface 12f parallel to the light exit surface 12b is larger.

In other words, the light bar 12 has a two-stage wedge shape in which the reflecting surface 12c1 provided at the root portion 12d has a larger inclination than the reflecting surface 12c2 provided at the tip portion 12e.

Next, details of the prism 12g formed on the light exit surface 12c of the light bar 12 will be described with reference to FIGS. 3C and 3D. 3C is an enlarged view of region H in FIG. 3A, and FIG. 3D is an enlarged view of region J in FIG. 3A. That is, FIG. 3C is a diagram for explaining the prism 12g formed in the region H near the root portion 12d in the tip portion 12e, and FIG. 3D is separated from the root portion 12d in the tip portion 12e. 5 is a diagram for explaining a prism 12g formed in a region J. FIG.

As shown in FIG. 3C, a plurality of prisms 12g are formed along the longitudinal direction (X-axis direction) of the light bar 12 on the light exit surface 12c in the region H. The prism 12g has an inclined surface 12g1 and an inclined surface 12g2.

The inclined surface 12g1 is inclined in a direction away from the light exit surface 12b as it goes from one end (light entrance surface 12a side) of the light bar 12 to the other end. The inclined surface 12g2 is inclined in a direction approaching the light exit surface 12b as it goes from one end (light incident surface 12a side) of the light bar 12 to the other end. Further, the inclined surface 12g2 of one prism 12g is formed continuously with the inclined surface 12g1 of the adjacent prism 12g.

Furthermore, as shown in FIG. 3D, a plurality of prisms 12g are also formed side by side along the longitudinal direction (X-axis direction) of the light bar 12 on the light exit surface 12c in the region J.

Here, in the sectional view of the XY plane, the angle φ4 formed by the inclined surface 12g2 of the prism 12g in the region H shown in FIG. 3C and the surface 12f parallel to the light exit surface 12b is the inclination of the prism 12g in the region J shown in FIG. 3D. It is smaller than the angle φ5 formed by the surface 12g2 and the surface 12f parallel to the light exit surface 12b. That is, as it goes from one end (light incident surface 12a side) to the other end of the light bar 12, the angle formed by the inclined surface 12g2 of the prism 12g and the surface 12f parallel to the light exit surface 12b is gradually increased. To change.

On the other hand, in the cross-sectional view of the XY plane, the angle φ6 formed by the inclined surface 12g1 and the inclined surface 12g2 is an angle common to all the prisms 12g. With the prism 12g described so far, the light distribution in the X-axis direction on the light exit surface 12b of the light bar 12 can be accurately controlled.

Next, the prism 12j formed on the light exit surface 12b of the light bar 12 will be described with reference to FIG. 3E. 3E is a cross-sectional view taken along line KK in FIG. 3A. FIG. 3E shows the side surfaces 12k and 12m of the light bar 12 substantially parallel to the XY plane.

As shown in FIG. 3E, a plurality of prisms 12j are formed side by side along the short direction (Z-axis direction) of the light bar 12 on the light exit surface 12b of the light bar 12 in a sectional view of the YZ plane. The prism 12j has an inclined surface 12j1 and an inclined surface 12j2.

The inclined surface 12j1 is inclined in a direction away from the surface 12h parallel to the light exit surface 12b as it goes from one end (side surface 12k side) to the other end (side surface 12m side) in the short direction of the light bar 12. The inclined surface 12j2 is inclined in a direction approaching the surface 12h parallel to the light exit surface 12b as it goes from one end (side surface 12k side) to the other end (side surface 12m side) in the short direction of the light bar 12.

And the apex angle φ7 of the angle formed by the inclined surface 12j1 and the inclined surface 12j2 (the apex angle of the prism 12j) is 90 °, for example. Further, an angle φ8 formed by the inclined surface 12j1 and the surface 12h and an angle φ9 formed by the inclined surface 12j2 and the surface 12h are, for example, 45 °.

Here, as shown in FIG. 3E, the prism 12j changes the path of the light 101 incident on the light bar 12 in a direction parallel to the Y-axis direction, thereby converting the light 101 into the light incident surface 13a of the prism sheet 13. Can be made incident. As described above, the light distribution in the Z-axis direction can be accurately controlled by the prism 12j.

Furthermore, as described above, the light distribution in the X-axis direction can be controlled by forming the prism 12g on the light exit surface 12c. That is, in the light bar 12 according to the embodiment, the light distribution in the X-axis direction and the Z-axis direction can be accurately controlled.

When the apex angle φ7 of the prism 12j is 90 °, the light distribution angle in the Z-axis direction on the exit surface 5d of the light guide plate 5 can be minimized. On the other hand, by making the apex angle φ7 larger than 90 °, the light distribution in the Z-axis direction on the exit surface 5d of the light guide plate 5 can be widened.

Next, details of the prism sheet 13 according to the embodiment will be described with reference to FIGS. 4A and 4B. FIG. 4A is an enlarged view of a central portion in the longitudinal direction (X-axis direction) of the prism sheet 13 according to the embodiment.

As shown in FIG. 4A, a plurality of prisms 13 d are formed side by side along the longitudinal direction (X-axis direction) of the prism sheet 13 on the light incident surface 13 a in the center of the prism sheet 13. The prism 13d has an inclined surface 13d1 and an inclined surface 13d2.

The inclined surface 13d1 is inclined in a direction away from the light exit surface 13b as it goes from one end (X-axis negative direction side) in the longitudinal direction of the prism sheet 13 to the other end (X-axis positive direction side). The inclined surface 13d2 is inclined in a direction approaching the light exit surface 13b as it goes from one end (X-axis negative direction side) in the longitudinal direction of the prism sheet 13 to the other end (X-axis positive direction side). Further, the inclined surface 13d2 of one prism 13d is formed continuously with the inclined surface 13d1 of the adjacent prism 13d.

4A, the prism 13d changes the path of the light 102 incident on the prism sheet 13 in a direction parallel to the Y-axis direction, so that the light 102 is incident on the light incident surface 4a of the visual field control film 4. Can be made incident. For example, the light 102 incident on the inclined surface 13d1 of the prism 13d is reflected toward the light incident surface 4a by the inclined surface 13d2. Thus, the light distribution in the X-axis direction can be controlled by the prism 13d.

FIG. 4B is an enlarged view of the vicinity of the end portion in the longitudinal direction of the prism sheet 13 according to the embodiment, specifically, an enlarged view of the vicinity of the end portion on the linear light source 3A side. As shown in FIG. 4B, a plurality of prisms 13d are also formed side by side along the longitudinal direction (X-axis direction) of the prism sheet 13 on the light incident surface 13a in the vicinity of the end.

Note that the shapes of the plurality of prisms 13 d in the cross-sectional view of the XY plane are line symmetric with respect to the line segment passing through the center C of the planar illumination device 1. That is, the light incident surface 13a is inclined toward the center C from both ends of the prism sheet 13 in the X-axis direction, and is inclined in a direction approaching the light output surface 13b and an inclined surface 13d1 inclined in a direction away from the light output surface 13b. A plurality of prisms 13d having continuous inclined surfaces 13d2 are formed side by side along the X-axis direction.

Then, as shown in FIG. 4B, the prism 13 d changes the path of the light 103 incident on the prism sheet 13 in a direction parallel to the Y-axis direction, thereby causing the light 103 to enter the light incident surface 4 a of the visual field control film 4. Can be made incident.

Here, in the sectional view of the XY plane, the angle φ10 formed by the inclined surface 13d1 of the prism 13d in the central portion of the prism sheet 13 shown in FIG. 4A and the surface 13f parallel to the light exit surface 13b is the prism sheet shown in FIG. 4B. 13 is smaller than the angle φ13 formed by the inclined surface 13d1 and the surface 13f of the prism 13d in the vicinity of the end portion.

That is, the inclination angle (angle φ10) of the inclined surface 13d1 formed in the central portion of the light incident surface 13a is smaller than the inclination angle (angle φ13) of the inclined surface 13d1 formed near the end of the light incident surface 13a.

4A, the angle φ11 formed by the inclined surface 13d2 of the prism 13d in the central portion of the prism sheet 13 shown in FIG. 4A and the surface 13f parallel to the light exit surface 13b is the prism sheet 13 shown in FIG. 4B. Is larger than the angle φ14 formed by the inclined surface 13d2 and the surface 13f of the prism 13d in the vicinity of the end of the prism 13d.

That is, the inclination angle (angle φ11) of the inclined surface 13d2 formed at the central portion of the light incident surface 13a is larger than the inclination angle (angle φ14) of the inclined surface 13d2 formed near the end of the light incident surface 13a.

On the other hand, in the cross-sectional view of the XY plane, the angle φ12 formed by the inclined surface 13d1 and the inclined surface 13d2 is an angle common to all the prisms 13d.

In the sectional view of the XY plane, in the prism 13d positioned at the center C, the angle φ10 formed by the inclined surface 13d1 and the surface 13f is equal to the angle φ11 formed by the inclined surface 13d2 and the surface 13f. That is, in the cross-sectional view of the XY plane, the shape of the prism 13d located at the center C is an isosceles triangle.

As described above, the shape of the plurality of prisms 13d in the cross-sectional view of the XY plane is line symmetric with respect to the line segment passing through the center C of the planar illumination device 1. Thereby, even if a pair of LED11 irradiates light from a different direction, the direction of light can be aligned in the predetermined direction B by the prism sheet 13.

The light exit surface 13b of the prism sheet 13 may be planar, or as shown in FIGS. 4A and 4B, a lenticular lens in which a plurality of convex lenses 13e are arranged in the X-axis direction may be provided. The light distribution in the X-axis direction can be increased by increasing the contact angle between the convex lens 13e and the light exit surface 13b.

That is, the light distribution in the X-axis direction can be accurately controlled by appropriately adjusting the contact angle between the convex lens 13e and the light exit surface 13b. Therefore, the light distribution in the X-axis direction on the exit surface 5d of the light guide plate 5 can be accurately controlled. Furthermore, by making the pitch interval between the adjacent convex lenses 13e narrower than the pitch interval between the prisms 13d facing each other, it is possible to improve the uniformity of luminance in the X-axis direction.

Next, details of the visual field control film 4 according to the embodiment will be described with reference to FIG. 5A. FIG. 5A is a view for explaining the visual field control film 4 according to the embodiment, and specifically, a cross-sectional view in the XY plane.

The visual field control film 4 has a light transmission part 4c as a base material and a plurality of light absorption parts 4d. The light transmitting portion 4c has a function of transmitting light, and is made of, for example, a light transmitting resin. The light absorbing portion 4d has a function of absorbing light and is made of, for example, a light absorbing resin. The light absorbing portion 4d has a band shape, and is arranged so that the longitudinal direction thereof is aligned in a predetermined direction (for example, the peak direction P of light emitted from the prism sheet 13 in a cross-sectional view of the XY plane). The

As a result, as shown in FIG. 5A, for example, light 104 or light 105 having a small inclination with respect to the peak direction P can pass through the light transmitting portion 4c from the light incident surface 4a to the light exit surface 4b, whereas the peak direction The light 106 having a large inclination with respect to P is absorbed by the light absorbing portion 4d and cannot reach the light exit surface 4b.

That is, by providing the visual field control film 4, unnecessary light (for example, light 106) greatly deviating from the peak direction P when cut in a cross-sectional view in the XY plane, that is, in a plane parallel to the exit surface 5 d of the light guide plate 5. Can be prevented from entering the light guide plate 5. Thereby, it is possible to improve the light distribution in the X-axis direction of the light emitted with the direction changed by the light guide plate 5.

In the embodiment, in the cross-sectional view of the XY plane, the light emitted from the light exit surface 4b of the visual field control film 4, that is, the light emitted from the

linear light sources

3A and 3B to the light guide plate 5 has a full width at half maximum of 20 ° or less. There should be. Moreover, the visual field control film 4 is good to restrict | limit the light distribution angle in the range of ± 60 degrees or less in the cross-sectional view of XY plane. Thereby, the light distribution in the X-axis direction of the light emitted with the direction changed by the light guide plate 5 can be further improved.

Although FIG. 5A shows the case where the peak direction P is parallel to the Y-axis direction, the peak direction P is not limited to being parallel to the Y-axis direction. For example, as shown in FIG. 5B, when the peak direction P is tilted from the Y-axis direction, the longitudinal direction of the light absorbing portion 4d may be tilted from the Y-axis direction so as to be along the peak direction P. FIG. 5B is a diagram for explaining another example of the visual field control film 4 according to the embodiment. Thereby, similarly to the example shown in FIG. 5A, it is possible to suppress the transmission of the light 106 having a large inclination with respect to the peak direction P.

In the embodiment, a resin having a high reflectance (for example, a white resin) may be used for the housing frame 2 around the LED 11 and in the vicinity of the light incident surface 12a of the light bar 12. Thereby, the efficiency of light can be improved. Further, a resin (for example, black resin) having a high absorption rate may be used for the housing frame 2 other than the above-described parts. Thereby, unnecessary light distribution can be reduced. That is, the housing frame 2 is preferably formed by two-color molding using a white resin and a black resin.

Furthermore, the planar illumination device 1 according to the embodiment includes a surface other than the light incident surface 12a and the light output surface 12b in the light bar 12, a surface other than the light incident surface 13a and the light output surface 13b in the prism sheet 13, and the light guide plate 5. In this case, it is preferable that the light be specularly reflected on the surface having a width of about 2 mm adjacent to the side surface 5c. For example, such a surface may be covered with a specular reflection sheet having a U-shaped cross section. Thereby, the efficiency of light can be improved and unnecessary light distribution can be reduced.

Furthermore, the planar illumination device 1 according to the embodiment is configured such that light is absorbed by the terminal end portion (the lower end portion in FIG. 1A) and the side surface portion (the left and right side surfaces in FIG. 1A) of the light guide plate 5. It is good to be. For example, such a portion may be painted with a black coating material. Thereby, unnecessary light distribution can be reduced.

(Modification)
Hereinafter, various modifications of the embodiment will be described. In the following description, the same parts as those in the embodiment are denoted by the same reference numerals, and redundant descriptions may be omitted. First, Modification 1 of the embodiment will be described with reference to FIGS. 6A and 6B.

FIG. 6A is a front view of the planar lighting device 1 according to the first modification of the embodiment, and FIG. 6B is an enlarged view of a region M in FIG. 6A. As shown in FIG. 6A, in Modification 1, only one linear light source is provided instead of a pair as in the embodiment (linear light source 3A).

Further, as shown in FIG. 6B, in the light guide plate 5, the prism 5 f is inclined with respect to a predetermined direction B (in the figure, from the X axis positive direction and the Y axis negative direction to the X axis negative direction and the Y axis positive direction). Extending). Thereby, in the modification 1, light can be irradiated toward a desired one direction (X-axis positive direction and Y-axis negative direction in the drawing) by the prism 5f.

Subsequently, Modification 2 of the embodiment will be described with reference to FIGS. 7A and 7B. FIG. 7A is an enlarged view of the first light guide 5a according to Modification 2 of the embodiment, and FIG. 7B is an enlarged view of the second light guide 5b according to Modification 2 of the embodiment. 7A is an enlarged view of a region D (see FIG. 1A) in the embodiment, and FIG. 7B is an enlarged view of a region E (see FIG. 1A) in the embodiment.

As shown in FIG. 7B, in the second light guide 5b, the prism 5f extends obliquely with respect to the predetermined direction B as in the embodiment, whereas the first light guide 5b as shown in FIG. 7A. In the optical part 5a, the prism 5f extends in a direction perpendicular to the predetermined direction B.

Thus, by forming the prism 5f so as to extend in a direction perpendicular to the predetermined direction B, the emission direction can be aligned with the predetermined direction B on the XY plane as shown in FIG. 7A. Furthermore, by forming the prism 5f tilted from the predetermined direction B in the second light guide 5b, it is possible to irradiate with the emission direction tilted from the predetermined direction B on the XY plane.

Thus, by changing the direction of the prism 5f in the first light guide 5a and the second light guide 5b as appropriate, the planar illumination device 1 can change the emission direction in two different directions.

Subsequently, Modification 3 of the embodiment will be described with reference to FIGS. 8 to 10B. FIG. 8 is a cross-sectional view of the planar lighting device 1 according to the third modification of the embodiment, and corresponds to FIG. 1B in the embodiment. The third modified example is an example in which the visual field control film 4 in the embodiment is changed to a visual field control film 4A having a different structure.

Details of the visual field control film 4A are shown in FIG. FIG. 9 is a diagram for explaining a visual field control film 4A according to Modification 3 of the embodiment, specifically, a cross-sectional view in the YZ plane.

The visual field control film 4 A has a light transmission part 4 c that is a base material and a plurality of light absorption parts 4 d, similarly to the visual field control film 4. On the other hand, unlike the visual field control film 4, the light absorbing portion 4 d having a band shape is arranged so that the longitudinal direction is aligned with the peak direction P of the light emitted from the prism sheet 13 in the cross-sectional view of the YZ plane. The

As a result, as shown in FIG. 9, the light 107 and the light 108 having a small inclination with respect to the peak direction P can be transmitted through the light transmitting portion 4 c from the light incident surface 4 a to the light exit surface 4 b in the cross-sectional view of the YZ plane. it can. On the other hand, the light 109 having a large inclination with respect to the peak direction P is absorbed by the light absorbing portion 4d and cannot reach the light exit surface 4b.

That is, by providing the visual field control film 4A, unnecessary light (for example, light 109) that deviates significantly from the peak direction P when cut in a cross-sectional view in the YZ plane, that is, in a plane perpendicular to the longitudinal direction of the visual field control film 4A. Can be prevented from entering the light guide plate 5.

FIG. 10A is a diagram for explaining light distribution in the planar illumination device 1 of the reference example. Specifically, the reference example shown in FIG. 10A shows a planar illumination device 1 in which the visual field control film 4A is not provided.

As shown in FIG. 10A, when the visual field control film 4A is not provided, the light guide plate 5 has not only the light 107 and the light 108 with a small inclination with respect to the peak direction P but also the peak direction P in the cross-sectional view of the YZ plane. Light 109 having a large inclination with respect to is also incident. Then, the light 107 and the light 108 having a small inclination with respect to the peak direction P are reflected by the first region 5f1 and the second region 5f2 of the prism 5f inside the light guide plate 5, and are transmitted in a predetermined direction (Y-axis negative direction and Z-axis). The light is emitted in the positive direction.

On the other hand, the light 109 having a large inclination with respect to the peak direction P is repeatedly reflected by the light exit surface 5d and the first region 5f1 of the prism 5f inside the light guide plate 5, and finally reflected by the second region 5f2 to be predetermined. Is emitted in a direction different from the direction (Y-axis positive direction and Z-axis positive direction).

Therefore, when the field-of-view control film 4A is not provided, it is difficult to improve the light distribution in the Y-axis direction of the light that is changed in direction by the light guide plate 5 and emitted. That is, in the reference example, there is a possibility that a driver on the Y axis positive direction side or a person sitting in the passenger seat may feel dazzled.

FIG. 10B is a diagram for explaining light distribution in the planar illumination device 1 according to the third modification of the embodiment. As shown in FIG. 10B, when the visual field control film 4A is provided, the light 107 and the light 108 having a small inclination with respect to the peak direction P are incident on the light guide plate 5 in the cross-sectional view of the YZ plane. Light 109 having a large inclination with respect to is not incident.

Thereby, it is possible to reduce the light emitted in a direction (Y-axis positive direction and Z-axis positive direction) different from the predetermined direction due to the light 109. Therefore, according to the modification 3, the light distribution property in the Y-axis direction of the light emitted with the direction changed by the light guide plate 5 can be improved.

In the modified example 3, the light emitted from the light exit surface 4b of the visual field control film 4A, that is, the light emitted from the

linear light sources

3A and 3B to the light guide plate 5 in the cross-sectional view of the YZ plane is 20 ° or less at a full width at half maximum. It is good to be. Further, in the field-of-view control film 4A, in the cross-sectional view of the YZ plane, the light distribution angle may be limited within a range of ± 60 ° or less, and more preferably limited within the range of ± 45 ° or less. Thereby, the light distribution in the Y-axis direction of the light emitted with the direction changed by the light guide plate 5 can be further improved.

FIG. 11 is a cross-sectional view of the planar illumination device 1 according to the fourth modification of the embodiment. Modification 4 is an example in which both the visual field control film 4 provided in the embodiment and the visual field control film 4A provided in Modification 3 are used.

Specifically, as shown in FIG. 11, the visual field control film 4 and the visual field control film 4 A are laminated and disposed between the prism sheet 13 and the light guide plate 5. In the fourth modification, the visual field control film 4 can improve the light distribution in the X-axis direction of the light emitted from the light guide plate 5 whose direction is changed, and the visual field control film 4A allows the light guide plate 5 to be improved. It is possible to improve the light distribution in the Y-axis direction of the light emitted with the direction changed by.

In Modification 4, it is preferable to directly bond the visual field control film 4 and the visual field control film 4A. Thereby, since the change of the refractive index between the visual field control film 4 and the visual field control film 4A can be suppressed, the attenuation of light between the visual field control film 4 and the visual field control film 4A is suppressed. be able to. Therefore, the luminous efficiency of the planar lighting device 1 can be improved.

FIG. 12 is a diagram showing a light distribution in the planar lighting device 1 of the reference example. Note that the light distribution shown in FIG. 12 indicates that the darker the color, the higher the luminance. Further, the orientation of the azimuth angle and polar angle in the light distribution shown in FIG. 12 will be described with reference to FIGS.

FIG. 13 is a diagram for explaining the azimuth angle in the light distribution shown in FIG. As shown in FIG. 13, in the light distribution shown in FIG. 12, with respect to the light emitted from the second light guide portion 5b of the light guide plate 5, the X-axis positive direction is set to an azimuth angle of 0 °, and the Y-axis negative direction is set to The azimuth angle is 90 °, the negative X-axis direction is 180 °, and the positive Y-axis direction is 270 °. An azimuth angle of 90 ° (Y-axis negative direction) corresponds to the front side of the vehicle, and an azimuth angle of 270 ° (Y-axis positive direction) corresponds to the rear side of the vehicle.

FIG. 14 is a diagram for explaining polar angles in the light distribution shown in FIG. As shown in FIG. 14, in the light distribution shown in FIG. 12, with respect to the light emitted from the exit surface 5d of the light guide plate 5, the positive Z-axis direction is 0 ° and the vertical direction is perpendicular to the positive Z-axis direction. The direction is a polar angle of 90 °, and the opposite direction of the perpendicular direction is a polar angle of −90 °. For example, as shown in FIG. 14, when the positive Y-axis direction is 90 ° polar angle, the negative Y-axis direction is −90 ° polar angle.

Returning to the explanation of FIG. As shown in FIG. 12, the planar illumination device 1 of the reference example is configured to emit light in a predetermined direction centered on an azimuth angle of about 25 ° and a polar angle of about 50 °. . On the other hand, the planar illumination device 1 of the reference example emits light in a direction different from the predetermined direction.

FIG. 15 is a view showing a cross section of the light distribution of the embodiment, the third modification, the fourth modification, and the reference example. Specifically, FIG. 15 is a cross section at an azimuth angle of about 337 ° (corresponding to the broken line 110 in FIG. 12) in the luminance distribution in the hemispherical direction in which the positive Z-axis direction shown in FIG. The brightness is shown.

In FIG. 15, the region where the polar angle is near 0 ° is a region where the luminance is increased when the light distribution is disturbed in the X-axis direction, and the region where the polar angle is near 63 ° is the light distribution in the Y-axis direction. This is a region where the brightness increases when disturbed.

As shown in FIG. 15, in the reference example in which neither the visual field control film 4 nor the visual field control film 4A is provided, the luminance is high regardless of whether the polar angle is near 0 ° or 63 °. It can be seen that the light distribution is somewhat disturbed both in the direction and in the Y-axis direction.

On the other hand, in the embodiment in which the visual field control film 4 is provided, the light distribution is improved in the X-axis direction because the luminance is reduced near the polar angle of 0 ° as compared with the reference example. I understand.

Further, in the third modification in which the visual field control film 4A is provided, since the luminance is reduced near the polar angle of 63 ° as compared with the reference example, the light distribution is improved in the Y-axis direction. I understand.

Furthermore, in the modified example 4 in which both the visual field control film 4 and the visual field control film 4A are provided, the luminance is reduced even when the polar angle is around 0 ° or the polar angle is around 63 ° as compared with the reference example. From this, it can be seen that the light distribution in both the X-axis direction and the Y-axis direction is improved.

As described above, according to the embodiment, when the prism 5f formed on the back surface 5e of the light guide plate 5 is cut in parallel to the predetermined direction B, the first region 5f1 substantially parallel to the emission surface 5d The second region 5f2 is inclined with respect to the emission surface 5d, and the first region 5f1 and the second region 5f2 are formed so as to extend obliquely with respect to the predetermined direction B. Both light properties and high light distribution can be achieved.

In the above embodiment, the

linear light sources

3A and 3B are formed using the LED 11 and the light bar 12, but the configuration of the linear light source is not limited to this example. For example, a linear light source may be formed by arranging a plurality of LEDs in a line. In the above-described embodiment, the planar illumination device 1 is formed symmetrically about the center C as an axis, but may not be formed symmetrically.

In the above-described embodiment, the configuration of the prism sheet 13 is bilaterally symmetric, but the prism sheet 13 may be configured differently on the left and right. Thereby, the light of the different direction can be incident on the 1st light guide part 5a and the 2nd light guide part 5b of the light guide plate 5, respectively. Furthermore, in the above embodiment, the prism sheet 13 is integrally formed. However, like the light bar 12, the prism sheet 13 may be divided into left and right.

As described above, the planar illumination device 1 according to the embodiment includes the light sources (linear

light sources

3A and 3B) and the light guide plate 5. The light sources (linear

light sources

3A and 3B) emit light in a predetermined direction B. The light guide plate 5 has a side surface 5c, an exit surface 5d that is one main surface, and a back surface 5e that is the other main surface. A prism 5f is formed on the back surface 5e, and light sources (linear

light sources

3A and 3B) are formed. ) Is incident on the side surface 5c from the exit surface 5d. The prism 5f includes a first region 5f1 that is substantially parallel to the exit surface 5d and a second region 5f2 that is inclined with respect to the exit surface 5d when cut in parallel to the predetermined direction B. The first region 5f1 and the second region 5f2 extend obliquely with respect to the predetermined direction B. Thereby, both the translucency and the high light distribution can be achieved.

Further, in the planar illumination device 1 according to the embodiment, the light emitted from the emission surface 5d is emitted in a range of 40 ° or less at the full width at half maximum. Thereby, while irradiating a required area | region fully, it can further suppress that an unnecessary area | region is irradiated.

Moreover, the planar illumination device 1 according to the embodiment further includes a visual field control film 4 configured to be capable of limiting the light distribution angle between the light source (linear

light sources

3A and 3B) and the side surface 5c of the light guide plate 5. Prepare. Thereby, the light distribution property of the light emitted by changing the direction by the light guide plate 5 can be improved.

In the planar illumination device 1 according to the embodiment, the visual field control film 4 has a light distribution angle with respect to a predetermined direction of ± 60 ° or less (preferably ± 45) when cut by a plane parallel to the emission surface 5d. Limit in the range of ° or less. Thereby, the light distribution in the X-axis direction of the light emitted with the direction changed by the light guide plate 5 can be further improved.

In the planar illumination device 1 according to the embodiment, the visual field control film 4A has a light distribution angle in a range of ± 60 ° or less (preferably ± 45 ° or less) when cut along a plane perpendicular to the longitudinal direction. Limit with. Thereby, the light distribution in the Y-axis direction of the light emitted with the direction changed by the light guide plate 5 can be further improved.

In the planar illumination device 1 according to the embodiment, the light sources are linear

light sources

3A and 3B extending along the side surface 5c. Thereby, planar light can be emitted from the light guide plate 5.

In the planar illumination device 1 according to the embodiment, two

linear light sources

3A and 3B are arranged along the side surface 5c. Thereby, two different places (for example, the driver's seat side and the passenger seat side) can be irradiated with light independently.

In the planar lighting device 1 according to the embodiment, the light guide plate 5 includes a first light guide 5a and a second light guide 5b, and the first light guide 5a and the second light guide 5b. Thus, the extending directions of the first region 5f1 and the second region 5f2 are different from each other. Thereby, two different places (for example, the driver's seat side and the passenger seat side) can each be irradiated with light with high orientation.

Further, the present invention is not limited by the above embodiment. What comprised suitably combining each component mentioned above is also contained in this invention. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspect of the present invention is not limited to the above-described embodiment, and various modifications can be made.

1 Surface illumination device, 2 housing frame, 3A, 3B linear light source, 4, 4A visual field control film, 5 light guide plate, 5a first light guide, 5b second light guide, 5c side, 5d exit surface, 5e Back surface, 5f prism, 5f1, first area, 5f2, second area, 10 FPC, 11 LED (light source), 12 light bar, 13 prism sheet

Claims

A light source that emits light in a predetermined direction;
It has a side surface, an exit surface that is one main surface, and a back surface that is the other main surface. A prism is formed on the back surface, and light incident on the side surface from the light source is emitted from the exit surface. A light guide plate;
With
The prism is
A first region that is substantially parallel to the emission surface and a second region that is inclined with respect to the emission surface when cut in parallel to the predetermined direction; the first region and the second region; Extending in an oblique direction with respect to the predetermined direction,
Planar lighting device.
The light emitted from the emission surface is emitted in a range of 40 ° or less at full width at half maximum.
The planar illumination device according to claim 1.
Further comprising a visual field control film configured to limit a light distribution angle between the light source and the side surface of the light guide plate.
The planar illumination device according to claim 1 or 2.
The visual field control film is
When cut by a plane parallel to the exit surface, the light distribution angle is limited within a range of ± 60 ° or less.
The planar illumination device according to claim 3.
The visual field control film is
When cut along a plane perpendicular to the longitudinal direction, the light distribution angle is limited within a range of ± 60 ° or less.
The planar illumination device according to claim 3 or 4.
The light source is
A linear light source extending along the side surface;
The planar illumination device according to any one of claims 1 to 5.
The two linear light sources are arranged along the side surface;
The planar illumination device according to claim 6.
The light guide plate is
A first light guide portion and a second light guide portion, wherein the first light guide portion and the second light guide portion have different directions in which the first region and the second region extend;
The planar illumination device according to any one of claims 1 to 7.