WO2018110336A1

WO2018110336A1 - Head-up display device

Info

Publication number: WO2018110336A1
Application number: PCT/JP2017/043408
Authority: WO
Inventors: 野村　英司
Original assignee: コニカミノルタ株式会社
Priority date: 2016-12-13
Filing date: 2017-12-04
Publication date: 2018-06-21
Also published as: JPWO2018110336A1

Abstract

This head-up display device has an image formation unit (101) for forming an image, a single intermediate screen (111) for producing display light corresponding to the image, and an optical system for transmitting display light emitted from the intermediate screen and causing the display light to be incident on a screen (WS), the optical system having a first mirror (M1) for reflecting the display light emitted from the intermediate screen, and a second mirror (M2) for further reflecting the display light reflected by the first mirror and causing the display light to be incident on the screen (WS), the present invention being configured so that the display light emitted from the intermediate screen (111) and the display light reflected by the second mirror (M2) intersect, and the display light is incident on the screen, whereby a virtual image is formed, and when a plane passing through the center of the intermediate screen (111) and including a line (L1) connecting the eye of an observer and the center of the virtual image is designated as a first imaginary plane, the second mirror (M2) has a reflecting surface having a convex arc in a cross section thereof cut by the first imaginary plane.

Description

Head-up display device

The present invention relates to a head-up display device mainly used in, for example, an automobile, and more specifically, a vehicle visually recognized by light transmitted through a windshield via a translucent display member (windshield or combiner). The present invention relates to a head-up display device capable of visually recognizing a front view and images and information provided by light reflected from a windshield in a driver (observer) view.

If you can display information such as the speed of instruments directly in the vehicle as a virtual image while driving a car, you can drive without changing the field of view and prevent accidents. Therefore, a head-up display device has been developed as a means of directly displaying information in the observer's field of view. In such a head-up display device, light emitted from the LCD is normally transmitted and reflected by a combiner made of a transparent base material including a windshield and a half mirror material. Accordingly, the observer can acquire information as a virtual image displayed on the windshield or the like, and simultaneously acquire external information such as a vehicle front view that is visible through the windshield or the like.

Here, since the height of the observer's viewpoint is not constant due to differences in physique or driving posture, the observer's viewpoint height is high so that the virtual image can be seen even if the observer's viewpoint height changes. Accordingly, it is desirable to adjust the projection point of the display light in the vertical direction. On the other hand, in Patent Document 1, the driving means is operated in accordance with the viewpoint position information of the observer, the mirror that reflects the display light is tilt-rotated, and the entire emission device is driven. A technique for adjusting the projection position of the display light onto the windshield according to the height of the viewpoint is disclosed.

Japanese Patent Laid-Open No. 2015-60180

By the way, the virtual image that can be visually recognized by the observer needs to be visible with both eyes of the observer and the distortion of the virtual image needs to be almost the same. The range in which the virtual image is visually recognized with both eyes is called an eye box. However, according to the technique of Patent Document 1, since the eye box is small, a driving device that tilts and rotates the mirror by the driving means is required, and further, the entire emitting device needs to be driven to match the virtual image positions. This necessitates a drive system mechanism, resulting in high costs. On the other hand, if the eye box is made larger, the configuration in which the mirror is tilted and rotated by the driving means becomes unnecessary. It is disadvantageous for in-vehicle use.

The present invention has been made in view of the above-described problems, and an object thereof is to provide a head-up display device capable of forming a virtual image from a wide range of viewpoint positions while reducing the size and suppressing the cost.

The head-up display device of the present invention is
An image forming unit for forming an image;
A single intermediate screen for generating display light corresponding to the image formed by the image forming unit;
An optical system that allows display light emitted from the intermediate screen to pass through and is incident on the screen;
The optical system includes a first mirror that reflects display light emitted from the intermediate screen, and a second mirror that further reflects the display light reflected by the first mirror and causes the display light to enter the screen. The display light emitted from the intermediate screen intersects with the display light reflected by the second mirror, and a virtual image is formed by the display light entering the screen. And
The second mirror is a cross section cut along the first virtual plane when a plane including a line connecting the eyes of the observer and the center of the virtual image and passing through the center of the intermediate screen is the first virtual plane. And a reflecting surface having a convex arc.

According to the present invention, it is possible to provide a head-up display device capable of forming a virtual image from a wide range of viewpoint positions while reducing the size and suppressing the cost.

It is a figure which shows the state which mounted the head-up display apparatus concerning this Embodiment in the vehicle body VH. 2 is a diagram showing a configuration of a drawing unit 100. FIG. It is a whole optical path figure of a present Example. FIG. 4 is a partial optical path diagram in which a portion indicated by an arrow IV in FIG. 3 is enlarged. It is a figure which superimposes and shows the virtual image visually recognized within an eyebox.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a state in which the head-up display device according to the present embodiment is mounted on a vehicle body VH. A drawing unit 100 is arranged in the dashboard DB of the vehicle body VH, and the display light is projected onto the windshield (screen) WS of the vehicle body VH. The display light is guided to the pupil EY of the driver DR who is an observer by reflection from the windshield WS, and displays a virtual image (display image) V. On the other hand, the driver DR can observe a real image such as a landscape transmitted through the windshield WS in addition to the virtual image. The drawing unit 100 and the windshield WS constitute a head-up display device.

FIG. 2 is a diagram showing a schematic configuration of the drawing unit 100, which includes a line L1 that connects the pupil EY of the driver DR (FIG. 1) that is an observer and the center of the virtual image, and passes through the center of the light emitting surface 111a of the LCD 111. A plane (referred to as a first virtual plane) is shown. The drawing unit 100 mainly includes a drawing device 110 including an LCD 111 and an image forming unit 101, a first mirror M1, a second mirror M2, and a housing 130 that accommodates these. The first mirror M1 has a reflecting surface M1a having a concave arc on the first virtual surface. On the other hand, the second mirror M2 has a reflecting surface M2a having a convex arc on the first virtual surface. The first mirror M1 and the second mirror M2 constitute an optical system. The configuration of the drawing device is described in detail in, for example, Japanese Patent Application Laid-Open No. 2012-203176.

The LCD 111 as an intermediate screen is formed by adhering polarizing plates on both front and rear surfaces of a liquid crystal cell in which a liquid crystal layer is sealed in a pair of translucent substrates on which a transparent electrode film is formed. A light beam guided from a light source (not shown) to the LCD 111 passes through the LCD 111 driven corresponding to the image formed by the image forming unit 101 and becomes display light L representing an image to be displayed. The light emitting surface 111a of the LCD 111 is inclined at an angle θ with respect to the display light L emitted from the center of the light emitting surface 111a of the LCD 111 (in other words, the emission direction of the display light L with respect to the perpendicular of the light emitting surface 111a). It is preferable that the angle θ is inclined by 10 ° or more. Thereby, when stray light such as sunlight is incident along the optical path of the optical system, it can be prevented from being reflected by the light emitting surface 111a and reaching the vicinity of the driver DR via the mirror or the windshield WS.

The display light L emitted from the LCD 111 is reflected and enlarged by the first mirror M1 and the second mirror M2, and further reflected by the windshield WS to form a virtual image V at the pupil EY of the driver DR. By indicating information such as a navigation destination display arrow and speed display information through the virtual image V, the driver DR can easily obtain information while reducing eye movement.

According to the present embodiment, since the display light L emitted from the LCD 111 and directed to the first mirror M1 intersects with the display light L reflected by the second mirror M2 and directed to the windshield WS, the drawing unit 100 Is provided in the dashboard DB, the optical path length of the display light L can be secured relatively long and distortion can be suppressed. Therefore, distortion of an image formed in advance by the image forming unit 101 can be suppressed small. In addition, since the enlarged projection optical system that reflects the display light L with the reflecting surface M2a having a convex arc in the cross section of the first virtual surface can secure a large eye box, the drawing unit 100 and the mirror are rotated. A driving device is unnecessary, which contributes to cost reduction.

Hereinafter, examples suitable for the present embodiment will be described. FIG. 3 is an overall optical path diagram of the present embodiment in the first virtual plane. FIG. 4 is a partial optical path diagram in which a portion indicated by an arrow IV in FIG. 3 is enlarged.

In the data of the following examples, Si (i = 0, 1, 2, 3,...) Indicates the i-th surface (the virtual image surface is the 0th surface) counted from the virtual image surface side. Yes. S1 and S2 following S0 corresponding to the virtual image plane are virtual planes, and S3 corresponds to a pupil. S4 is a windshield, S6 is a first mirror, S5 is a second mirror, and S7 is a light emitting surface of the LCD.

The arrangement of each surface Si is specified by the surface vertex coordinates (x, y, z) and the rotation angle (ADE). The surface vertex coordinates of each surface Si are the local orthogonal coordinate system (X, y, z) in the global orthogonal coordinate system (x, y, z) with the surface vertex as the origin of the local orthogonal coordinate system (X, Y, Z). It is represented by the coordinates (x, y, z) of the origin of Y, Z) (unit: mm). In addition, the inclination of each surface Si is represented by a rotation angle ADE about the X axis with the surface vertex being the center. The unit of the rotation angle is °, and the counterclockwise direction when viewed from the negative direction of the X axis is the positive direction of the rotation angle of the X rotation. Further, the global orthogonal coordinate system (x, y, z) is an absolute coordinate system that coincides with the local orthogonal coordinate system (X, Y, Z) of the pupil S3. That is, the arrangement data of each surface Si is expressed in a global coordinate system with the pupil center as the origin. The direction from the pupil S3 toward the windshield is the -Z direction or -z direction, the upward direction with respect to the pupil is the + Y direction or + y direction, and the left direction when viewing the pupil from the windshield is the + X direction or + X direction.

In each embodiment, the windshield S4, the first mirror S6, and the second mirror S5 are free-form surfaces, and the free-form surface shape has the surface vertex as the origin, the Z-axis in the optical axis direction, and the optical axis. The height in the vertical direction is Z and is expressed by the following “Equation 1”. Tables 1 and 2 show surface data. c denotes a curvature at the vertex (1 / mm), k denotes a conic constant, the coefficient of the monomial x ^m y ⁿ (the free-form surface coefficients). It should be noted that for all data, the coefficients of the terms not described are all 0, and E−n = × 10 ⁻ⁿ .

The reference wavelength used for calculation in this example was 520 nm, and the light emitting surface size of the LCD was X direction: 40.896 mm × Y direction: 20.448 mm. The eye box size is −70 mm to +70 mm in the X direction and −60 mm to +60 mm in the Y direction.

c: vertex curvature, c = 1 / r
k: Conic coefficient
Cj: coefficient monomial x ^m y ⁿ R: Y radius of curvature

In this embodiment, the first mirror has a concave reflecting surface and the second mirror has a convex reflecting surface in the first virtual surface. In the cross section passing through the center of the mirror and parallel to the second imaginary plane, both the first mirror and the second mirror have a concave reflecting surface.

FIG. 5 shows a virtual image (a lattice image in which vertical and horizontal lines are orthogonally displayed on the LCD) visually recognized in the eye box in this embodiment. A virtual image that can be seen by changing the position of the eye point in the global Cartesian coordinate system (x, y, z) to (0, 0), (+70 mm, +60 mm), (+70 mm, −60 mm). The center of the virtual image is aligned. As shown in FIG. 5, it can be seen that even if the position of the eye point is changed, the lattice images are almost the same, and the same virtual image can be visually recognized in the entire eye box regardless of the viewpoint position of the driver. In addition, although not shown as an example of the present specification, if there is a difference in the shape of the virtual image in the eye box, grasp the position of the driver's eyes using an imaging device that can grasp the position of the driver's eyes, Visibility can be enhanced by displaying on the LCD an optimal image (for example, an intermediate image between the virtual image viewed with the right eye and the virtual image viewed with the left eye) according to the eye position of the driver.

The present invention is not limited to the embodiments described in the specification, and other embodiments and modifications are apparent to those skilled in the art from the embodiments and ideas described in the present specification. It is. For example, in the embodiment of the present invention, a symmetrical windshield is assumed. However, the windshield is not limited to this, and is not symmetrical, or has a symmetry and is tilted. But you can. Further, the display member and the head-up display device of the present invention can be used not only for automobiles but also for airplanes and heavy machinery.

The present invention can be used for a head-up display device.

100 Drawing Unit 110 Drawing Device 101 Image Forming Unit 111 LCD
130 Housing DB Dashboard DR Driver M1, M2 Mirror VH Car body WS Windshield

Claims

An image forming unit for forming an image;
A single intermediate screen for generating display light corresponding to the image formed by the image forming unit;
An optical system that allows display light emitted from the intermediate screen to pass through and is incident on the screen;
The optical system includes a first mirror that reflects display light emitted from the intermediate screen, and a second mirror that further reflects the display light reflected by the first mirror and causes the display light to enter the screen. The display light emitted from the intermediate screen intersects with the display light reflected by the second mirror, and a virtual image is formed by the display light entering the screen. And
The second mirror is a cross section cut along the first virtual plane when a plane including a line connecting the eyes of the observer and the center of the virtual image and passing through the center of the intermediate screen is the first virtual plane. A head-up display device having a reflective surface having a convex arc.
The head-up display device according to claim 1, wherein the first mirror has a reflecting surface having a concave arc in a cross section cut by the first virtual surface.
The first mirror and the second mirror when a plane passing through the intersection of the screen connecting the eye of the observer and the center of the virtual image and perpendicular to the first virtual plane is defined as the second virtual plane. 3. The head-up display device according to claim 1, wherein at least one of the mirrors has a reflective surface having a concave arc in a cross section cut by a plane parallel to the second imaginary plane through the center of the mirror. .
The head-up display device according to claim 3, wherein the screen is a windshield.
The head-up display device according to any one of claims 1 to 4, wherein the display light emitted from the center of the intermediate screen in the first virtual plane is tilted by 10 ° or more with respect to the normal of the intermediate screen.
The head-up display device according to any one of claims 1 to 5, wherein the image forming unit forms an image corrected so as to complement distortion occurring in the optical system and the screen.
7. The head-up display device according to claim 1, further comprising a device for recognizing an eye position of an observer, wherein the image forming unit forms an optimum image corresponding to the eye position of the observer.