JP2021063852A - Reflective display device for vehicles - Google Patents

Abstract

To allow for relatively stable displaying images against vertical change in eyepoint.SOLUTION: A reflective display device provided herein comprises a display 22 disposed on a vehicle's rear side of a windshield 10 and configured to display an image upward, and a mirror 26 erectly installed on an upper surface 12a of an instrument panel located above the display 22 and behind the windshield 10 and configured to reflect a display image 24 of the display 22 toward the rear to form a virtual image 28 on the vehicle's front side, where the mirror 26 is a convex mirror.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle reflective display device provided behind a vehicle windshield.

Conventionally, a reflection type display device is known as a device for displaying meters at a relatively long distance. For example, in Patent Document 1, a display, a concave mirror that magnifies and reflects the display image on the display surface of the display, and a light beam of the display image that is arranged between the display and the concave mirror and reflected by the concave mirror are used as an occupant. A display with a half mirror that reflects towards is shown.

As a result, the virtual image of the display can be shown to the driver, and the image of the meter or the like can be displayed relatively far away. In particular, the concave mirror reflection allows the display image to be displayed farther and larger than the original image.

Japanese Unexamined Patent Publication No. 8-286625

Here, in Patent Document 1, while the concave mirror reflection can display a larger display than the original image at a greater distance, the vertical movement of the image becomes large due to the movement of the viewpoint (= eye point) due to the driver's physique and the vertical movement of the line of sight. Phenomena that deviate from the visual range or a part of the image is missing are likely to occur. Therefore, an image position adjustment function is required, the configuration is complicated, and adjustment work is required.

The present invention provides a vehicle reflective display device capable of relatively stable display against vertical fluctuations of the eye point.

The vehicle reflective display device according to the present invention is installed on a display arranged on the vehicle rear side of the windshield and displaying an image upward, and on an instrument panel upper surface above the display and behind the windshield. A mirror that reflects the display image of the display toward the rear to form a virtual image on the front side of the vehicle, and the mirror is a convex mirror.

The display may be arranged at the bottom of a recess (hole) formed downward from the upper surface of the instrument panel behind the windshield.

The mirror may be a secondary convex mirror that is convex rearward in the vertical direction of the vehicle and flat in the left-right direction of the vehicle.

The mirror may be a tertiary convex mirror that is convex rearward in the vertical and horizontal directions of the vehicle.

According to the present invention, a wide viewing range and little movement (shaking) of the image itself can be obtained with respect to vertical fluctuations of the eye point, so that a stable display can be obtained regardless of disturbances such as the physique of the occupant and the riding posture. Can be obtained.

It is a figure which shows the structure of the reflection type display device for a vehicle which concerns on embodiment with the display of a driver. It is a figure which showed the relationship between the display image and a virtual image, (a) is a plane mirror, (b) is a concave mirror, (c) is a figure which shows the case of a convex mirror. It is a schematic diagram explaining that the viewing range can be expanded by a convex mirror. It is a figure explaining the relationship between a display and a virtual image, (a) shows the case of a plane mirror, (b) shows the case of a secondary convex mirror. It is a figure which shows the configuration example of the display device when seen from the driver.

Hereinafter, embodiments (embodiments) of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described herein.

"overall structure"
FIG. 1 is a diagram showing a configuration of a vehicle reflective display device according to an embodiment together with a driver's display.

The windshield 10 is provided on the upper part of the front surface of the vehicle body, and is made of a transparent material such as glass in order to secure a front view. An instrument panel (instrument panel) 12 is arranged below the rear side of the windshield 10, and the upper surface 12a of the instrument panel extends rearward from the lower end of the windshield 10.

Various operation buttons and display panels such as a navigation screen are arranged on the vehicle rear side surface (vehicle interior side surface) of the instrument panel 12, and the instrument panel upper surface 12a faces almost horizontally and is relatively flat. It is a face.

The steering wheel 14 is located on the rear side of the instrument panel 12. A steering shaft (not shown) extending diagonally forward and downward is fixed to the center of the steering 14. In this example, the steering 14 is ring-shaped.

A driver seat (not shown) is arranged behind the steering wheel 14, and the driver 16 sits there. The driver 16 operates the steering wheel 14 and also operates the accelerator, the brake, and the like to drive the vehicle.

The instrument panel upper surface 12a behind the windshield 10 is provided with a hole 20 in which the instrument panel upper surface 12a is recessed, and the display 22 is arranged at the bottom of the hole 20 with the display surface 22a facing upward. In the figure, the displayed display image 24 is schematically shown by arrows, but the display image 24 is a meter display such as a speedometer.

A mirror 26 is arranged above the display 22 and above the instrument panel upper surface 12a. As schematically shown, the mirror 26 is a convex mirror whose mirror surface is arranged obliquely downward so that the lower part is located in front of the vehicle and the rear surface (mirror surface) is convex. The vehicle width direction may be a flat secondary convex surface (cylindrical surface), or the vehicle width direction may be a tertiary convex surface (spherical surface) whose center side is convex. Further, the shape of the mirror surface may be a simple R (cylindrical surface, spherical surface), a non-simple R (aspherical surface) convex mirror for absorbing various aberrations, or a Fresnel lens. ..

By arranging such a mirror 26, when the driver 16 looks forward, the virtual image 28 of the display image 24 of the display 22 can be seen on the back side (front of the vehicle) of the mirror 26. That is, the virtual image 28 is formed on the extension of the straight line from the driver's eye (eye point) 16a to the mirror 26. Since the mirror 26 is a convex mirror, the distance from the mirror 26 to the virtual image 28 is shorter than the distance from the display image 24 to the mirror 26 on the display 22, and the height of the virtual image 28 is the display image 24 on the display 22. It will be lower.

As described above, in the virtual image 28 by the reflection type display device of the present embodiment, the viewing distance of the driver is slightly shorter and the size of the image is smaller than that of the plane mirror in the mirror 26. However, with respect to the vertical fluctuation of the eye point 16a of the driver 16, a wide viewing range and little movement (shaking) of the image itself can be obtained. In an important display such as a speedometer, it is important to always be able to visually recognize people of all physiques, all riding postures, and momentary movements of the eye point 16a due to disturbance, and the vehicle reflective display device of the present embodiment is used. It is very advantageous as a display device. In addition, it may not be necessary to adjust the display position according to the driver's physique when riding.

"Relationship between displayed image and virtual image"
FIG. 2 is a diagram showing the relationship between the display image 24 of the display 22 and the virtual image 28 by the mirror 26, in which (a) is a plane mirror, (b) is a concave mirror, and (c) is a convex mirror.

FIG. 2A shows a case where a plane mirror is used as the mirror 26. As a reference, when the direct-view type display 30 is used, the display 30 is provided on the vehicle interior side surface of the instrument panel 12, and the display image 32 is relatively close to the driver's eye point 16a on the front lower side. It is located at the position (distance C).

On the other hand, a mirror 26 is erected on the upper surface 12a of the instrument panel, and the distance B from the eye point 16a to the mirror 26 is B. The mirror 26 is a plane mirror, and the distance from the display 22 to the mirror 26 and the distance from the mirror 26 to the virtual image 28 are the same distance A. Therefore, the distance from the driver's eye point 16a to the virtual image 28 is A + B. The virtual image 28 of the display image 24 of the display 22 is actually visually observed with the addition of the distance A to the image on the display.

In this way, by using the plane mirror, the viewing distance to the virtual image 28 becomes A + B, which can be generally larger than C (A + B> C). Further, the position of the virtual image 28 is higher than that of the display image 32 in the case of direct viewing, and the amount of movement of the eye point when moving the eyes from the front to the virtual image 28 is also smaller than that of the display image 32 in the case of direct viewing.

In the plane mirror reflection, the height H0 of the display image 24 on the display 22 and the height H0 of the virtual image 28 are the same (H0 = H0).

In FIG. 2B, a concave mirror is used as the mirror 26. In this case, the distance from the mirror to the virtual image 28 extends to A1 due to the magnifying effect of the concave mirror (A1> A). That is, the viewing distance of the virtual image 28 by the driver is A1 + B, which is larger than the viewing distance A + B in the plane mirror (A1 + B> A + B), and the effect of distant arrangement can be obtained.

Further, the virtual image 28 can also be H1 (H1> H0) larger than the height H0 of the display image 24 on the display 22. The concave mirror may be a secondary (cylindrical surface) concave mirror or a tertiary (spherical) concave mirror. The difference between the two is whether the enlargement is only the height (partial magnification) or the similar enlargement including the width direction.

FIG. 2C shows a case where a convex mirror is used as the mirror 26 shown in FIG. Since a convex mirror is used, the distance from the mirror 26 to the virtual image 28 is reduced to A2 (A2 <A). As a result, the viewing distance of the virtual image 28 by the driver becomes A2 + B, which is smaller than the viewing distance A + B in the plane mirror (A2 + B <A + B).

Further, the height H2 of the virtual image 28 is smaller than the height H0 of the display image 24 on the display 22 and becomes H2 (H2 <H0). The convex mirror may be a secondary (cylindrical surface) or a tertiary (spherical surface). The difference between the two is whether the height is reduced (partial magnification) or the similarity is reduced including the width direction. As described above, the virtual image 28 visually recognized by the driver is smaller, but can be arranged farther (A2 + B> C) than the display image 32 in the case of direct viewing, and can contribute to reducing the visual load of the driver.

In addition, the number of items to be displayed is increasing in order to monitor the situation of the own vehicle and other vehicles during automatic driving. The display device of the present embodiment is very useful as a display means other than the conventional meter and head-up display.

"Comparison of curved mirrors, concave mirrors, and convex mirrors"
Here, the stability against disturbance (robustness) is in the order of concave mirror <plane mirror <convex mirror, and if a convex mirror is used, a wide viewing range is obtained against vertical fluctuations of the eye point in exchange for a slight reduction in image size and viewing distance. And less movement (shaking) of the image itself can be obtained. Therefore, using a convex mirror is very advantageous as an in-vehicle display (reflection type display device).

In most head-up displays using concave mirrors, it is necessary to adjust the image display position up and down according to the driver's physique when riding, and concave mirrors and plane mirrors are also used in reflective display devices that display meters and the like. If so, it is likely that a similar adjustment function will be required. On the other hand, a reflective display device using a convex mirror may make it unnecessary.

Further, in the layout of a reflection type display device for displaying a meter or the like, it is desirable to display a flat aspect ratio from the viewpoint of mounting space and design. This is because the restrictions in the vertical direction are stricter and the restrictions in the horizontal direction are looser than the front visibility and mounting restrictions. On the other hand, the size of a typical display is larger than the required aspect ratio. In a flat mirror configuration, a part of the display whose upper and lower parts are cut by a flat mirror is often in the visible range, and the upper and lower areas are wasted. Alternatively, the above-mentioned display position adjustment function is incorporated by shifting the display range by using the waste portion. According to the concave mirror, the size of the display can be reduced with respect to the size of the display image, which is advantageous in terms of space.

"About convex mirrors"
FIG. 3 is a schematic view illustrating that the viewing range can be expanded when a convex mirror is used. In FIG. 3, for simplification, the line of sight is arranged horizontally, the mirror is arranged downward at 45 °, and the optical path is bent 90 ° downward. Further, the mirror 26 is drawn by synthesizing the case of a plane mirror and the case of a convex mirror. Here, regarding the plane mirror and the convex mirror, the distance A between the mirror 26 and the display 22 is the same in FIG. 2 assuming the actual vehicle configuration, but in FIG. 3, the position and size of the virtual image 28 are set by the plane mirror and the convex mirror in the drawing. In order to match, the distance between the mirror 26 and the display 22 is increased during the convex mirror (FIG. 3), and the size of the display image 24 on the display 22 is enlarged.

When the upper and lower ends a and b of the mirror are combined, the position of the midpoint c is slightly closer to the convex mirror, but the difference is small, so it is approximated by a straight line. In the figure, since the convexity is shown large, the midpoint c indicates the position of the plane mirror. As described above, this convex mirror may be a convex mirror of a so-called Fresnel mirror divided in the lateral direction. In this case, the cross section is actually almost straight.

In the case of a plane mirror in FIG. 3, a display image 24 (indicated by an arrow) having a height H on the display 22 is observed ahead of the mirror 26 as a virtual image 28 having a height H. The landing point at the eye point distance of the line connecting the upper end h1 of the virtual image 28 and the upper end a of the mirror 26 is the upper end e1 that can be visually recognized without missing the image, and the landing point of the line connecting the lower end h2 of the virtual image 28 and the lower end b of the mirror. However, it is the lower end e2 that can be visually recognized without missing the image. Therefore, the degree of freedom of the eye point is the distance between e1 and e2.

In the case of the convex mirror in FIG. 3, in order to obtain the virtual image 28 having a height H at the same position, the distance between the mirror 26 and the display 22 needs to be a little long, and the height of the display image 24 needs to be a little large.

When the position and size of the virtual image 28 are matched in this way, the position and height of the virtual image 28 observed from the eye point e are the same as in the case of the plane mirror.

However, when the eye point e is raised from this state, the optical path passing through the upper and lower ends a and b of the reflection point opens up and down due to the characteristics of the convex mirror. Therefore, the upper end landing point e3 in the case of the convex mirror is higher than the landing point e1 in the case of the plane mirror, and the lower end landing point is the point e4 lower than the landing point e2 in the case of the plane mirror. That is, in the case of the convex mirror, the position where the virtual image 28 can be visually recognized without being chipped is between e3 and e4, which is longer than between e1 and e2, and the image can be visually recognized in a wide range above and below the eye point.

This allows drivers in a wide range of physiques in the vehicle without adjusting the image position, and also without missing the image against dynamic eyepoint up and down movements while driving by the same driver. The effect is that it looks stable.

As described above, the optical path starting from the image has been described, but when the eye point is the starting point, the virtual image 28 descends a little as the eye point rises, and the image moves a little as the eye point descends. Visibility in a wide range is ensured.

4A and 4B are views for explaining the relationship between the display 22 and the virtual image 28, where FIG. 4A shows a plane mirror and FIG. 4B shows a case of a secondary convex mirror. When the required angle of view is flatter than that of the display 22 as described above, in the plane mirror configuration of FIG. 4A, the height of the image is the same for both the display image 24 and the virtual image 28 of the display 22, and the top and bottom of the screen are the same. The range of is eventually trimmed as an invisible portion that is reflected and invisible.

On the other hand, in the convex mirror configuration of FIG. 4B, the height of the display image 24 of the display 22 needs to be larger than that of the virtual image 28. Although the size of the virtual image 28 is reduced vertically, the number of vertical pixels used to form an image of the same height in the convex mirror is larger than that in the case of the plane mirror, resulting in a high-definition image in the vertical direction. A high-definition and clear image can be obtained on the display 22 having the same resolution, and conversely, when the image resolution is already sufficient, it becomes possible to select an inexpensive display having a low resolution.

FIG. 5 is a diagram showing a configuration example of a reflection type display device when viewed from the driver. The mirror 26 is held by a holding member 12b or the like formed on the upper surface of the instrument panel upper surface 12a. The display image of the display 22 is reflected by the mirror 26, and the virtual image 28 can be visually recognized by the driver. The mirror 26 may be held in the air by a holding member 12b formed on the upper surface of the instrument panel 12a as shown in the drawing, or may have a structure in which the instrument panel upper surface 12a itself rises and surrounds the mirror 26. Further, it may be held in the air by another structure extending from the windshield 10 or the like.

10 windshield, 12 instrument panel, 12a instrument panel top surface, 12b holding member, 14 steering wheel, 16 driver, 16a eye point, 20 holes, 22 display, 22a display surface, 24 display image, 26 mirror, 28 virtual image.

Claims (1)

A display placed on the rear side of the windshield and displaying the image upward,
A mirror that is erected on the upper surface of the instrument panel above the display and behind the windshield, reflects the display image of the display rearward, and forms a virtual image on the front side of the vehicle.
Including
The mirror is a convex mirror,
Reflective display device for vehicles.

Images