WO2018030203A1

WO2018030203A1 - Display device

Info

Publication number: WO2018030203A1
Application number: PCT/JP2017/027825
Authority: WO
Inventors: 研一笠澄; 久保田　孝介; 正人尾形; 森　俊也; 聡葛原; 裕昭岡山
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2016-08-10
Filing date: 2017-08-01
Publication date: 2018-02-15
Also published as: JP2018025693A

Abstract

A display device (10) according to the present invention comprises: a light source unit (11); a screen (13) that is disposed on then optical path between the light source (11) and a display medium (201); a scanning unit (12) that scans the screen (13) using light emitted from the light source unit (11); and a second mirror (15) that is disposed on the optical path such that an image formed on the screen (13) by the scanning is displayed as a virtual image (I1) on the display medium (201). At least one of the screen (13) and the second mirror (15) is disposed so as to reduce the distortion of the virtual image (I1) due to the scanning.

Description

Display device

The present invention relates to a display device.

As a display device for a vehicle, a head-up display (Head-Up Display, hereinafter also referred to as HUD) is known. The HUD displays, for example, figures such as numbers, letters, and arrows as information related to the vehicle state and route.

Also, some HUDs for vehicles present a driver with a virtual image formed in front of the windshield. Patent Document 1 discloses a technique for changing a projection position of a virtual image by moving a screen scanned with a laser beam in order to form an image in the optical axis direction.

JP 2009-150947 A

The present invention provides a display device capable of reducing distortion of a virtual image visually recognized by a user.

A display device according to one embodiment of the present invention is a display device that displays a virtual image using a display medium, and includes a light source unit, a screen, a scanning unit, and an optical system. The screen is disposed on the optical path from the light source unit to the display medium. The scanning unit performs scanning on the screen using the light emitted from the light source unit. The optical system is disposed on the optical path in order to display an image formed on the screen by scanning as a virtual image on the display medium. At least one of the screen and the optical system is arranged so as to reduce the distortion of the virtual image caused by the scanning.

The display device of the present invention can reduce distortion of a virtual image visually recognized by a user.

FIG. 1 is a diagram illustrating a usage example of the display device according to the embodiment. FIG. 2 is a view of the windshield (front glass) viewed from the inside of the vehicle. FIG. 3 is a diagram illustrating an example of a virtual image perceived by the driver through the windshield. FIG. 4 is a diagram illustrating a specific configuration of the display device according to the embodiment. FIG. 5 is a schematic diagram illustrating distortion of an image formed on the screen, which is generated by scanning of the scanning unit. FIG. 6 is a schematic diagram for explaining an example in which distortion is reduced by arrangement of screens. FIG. 7 is a schematic diagram for explaining an example in which distortion is reduced by the arrangement of the first mirror. FIG. 8 is a schematic diagram for explaining an example in which distortion is reduced by the arrangement of the second mirror. FIG. 9 is a schematic diagram for explaining an example in which distortion is reduced depending on the mounting direction of the second mirror.

Prior to the description of the embodiment of the present invention, problems in the conventional HUD will be briefly described. In HUD, distortion may occur in an image formed on a screen by scanning with laser light. Such distortion also appears in a virtual image visually recognized by the user.

A display device according to one embodiment of the present invention is a display device that displays a virtual image using a display medium, and includes a light source unit, a screen disposed on an optical path from the light source unit to the display medium, and emission from the light source unit. A scanning unit that performs scanning using the generated light on the screen, and an optical system that is disposed on the optical path to display an image formed on the screen by scanning as a virtual image on the display medium. At least one of the optical systems is arranged to reduce virtual image distortion caused by scanning.

Such a display device can reduce distortion of a virtual image visually recognized by the user.

Further, the optical system may include a mirror, and the mirror may be arranged so that the incident angle of the light to the mirror is an angle that reduces the distortion of the virtual image caused by scanning.

Such a display device can reduce distortion of a virtual image visually recognized by the user by arranging the mirror at an inclination.

Further, the mirror may be a concave mirror for enlarging and displaying the image as a virtual image on the display medium.

Such a display device can reduce distortion of a virtual image visually recognized by the user by arranging the concave mirror to be inclined.

Further, the screen may be arranged so that the incident angle of light to the screen is an angle that reduces the distortion of the virtual image generated by scanning.

Such a display device can reduce distortion of a virtual image visually recognized by the user by arranging the screen at an inclination.

Also, the scanning unit may be a MEMS (Micro Electro Mechanical System) mirror.

Such a display device can perform scanning using light emitted from the light source unit by the MEMS mirror.

The display medium may be a vehicle windshield.

Such a display device can display a virtual image using a windshield of a vehicle.

Hereinafter, embodiments will be specifically described with reference to the drawings. It should be noted that each of the embodiments described below shows a comprehensive or specific example. The numerical values, shapes, materials, constituent elements, arrangement positions and connecting forms of the constituent elements, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements.

Each figure is a schematic diagram and is not necessarily shown strictly. In each figure, substantially the same configuration is denoted by the same reference numeral, and redundant description may be omitted or simplified.

(Embodiment)
[Outline of display device]
First, an outline of the display device according to the embodiment will be described. FIG. 1 is a diagram illustrating a usage example of the display device according to the embodiment. FIG. 2 is a view of the windshield (front glass) viewed from the inside of the vehicle.

As shown in FIG. 1, the display device 10 according to the embodiment is an in-vehicle head-up display (HUD), and is attached near the upper surface of a dashboard 301 of a vehicle 300.

As shown in FIGS. 1 and 2, the display device 10 projects light onto a region D1 (a region surrounded by a broken line in FIG. 2) of the windshield 201 which is an example of a display medium. The projected light is reflected by the windshield 201.

The light reflected by the windshield 201 is directed to the eyes of the driver sitting in the driver's seat who is the user of the display device 10. The driver perceives the reflected light that has entered the eyes as a virtual image I1 located on the opposite side (outside of the vehicle) of the windshield 201 against the background of an actual object that can be seen through the windshield 201. In the embodiment, this series of situations is expressed by the display device 10 displaying the virtual image I1 using the windshield 201.

Next, an example of the virtual image I1 will be described. FIG. 3 is a diagram illustrating an example of the virtual image I1 perceived by the driver through the region D1 of the windshield 201. In FIG. 3, the hood 202 of the vehicle 300 is also illustrated.

3 is a part of the scenery in the field of view of the driver (not shown) driving the vehicle 300. Images P1 to P6 in FIG. 3 are specific examples of the virtual image I1 displayed by the display device 10. Other than these are objects in front of the vehicle 300 (or the windshield 201) that are visible to the driver. The images P1 to P6 appear to be located closer to the driver as the position in the region D1 is lower, and appear to be located farther from the driver as the position is higher in the region D1.

Images P1 and P2 each show the position of a pedestrian who is diagonally to the left of the vehicle 300. Image P3 shows a left turn point 80 meters ahead of vehicle 300. Images P4 to P6 show the traveling speed of the vehicle 300, the temperature of the cooling water, and the remaining amount of fuel, respectively.

[Specific configuration of display device]
Next, a specific configuration of the display device 10 will be described. FIG. 4 is a diagram illustrating a specific configuration of the display device 10.

The display device 10 includes a light source unit 11, a scanning unit 12, a screen 13, a first mirror 14, and a second mirror 15.

The light source unit 11 emits light indicating a virtual image displayed by the display device 10. For example, the light source unit 11 is configured by a pico projector including a laser light source that emits light of red (R), green (G), and blue (B) as a light emitter. The pico projector can display a highly visible virtual image regardless of the color and brightness of objects around the vehicle 300 and the vehicle body. Further, the light source unit 11 can focus by using a laser light source regardless of the distance or angle from the projection plane. Since the light source unit 11 is compact, the occupied space of the display device 10 in the dashboard 301 can be minimized.

The scanning unit 12 is disposed on the optical path of the emitted light from the light source unit 11, and performs scanning using the emitted light on the screen 13. That is, the scanning target is the screen 13. The scanning unit 12 is realized by, for example, a MEMS mirror. The screen 13 is constituted by a diffusion screen, for example. The scanning unit 12 forms an image on the screen 13 to be displayed as a virtual image by scanning the screen 13 with light emitted from the light source unit 11. The scanning of the screen 13 by the scanning unit 12 is, for example, two-dimensional scanning such as raster scanning. The scanning unit 12 is controlled by, for example, a CPU (Central Processing Unit) or a processor configured by a control unit (not shown) executing a program stored in a storage unit (not shown).

In the raster scan, for example, a one-dimensional scan from the upper left corner to the upper right corner is first performed. Next, the scanning position is moved on the screen 13 in a direction perpendicular to the one-dimensional scanning (for example, the downward direction), and the next one-dimensional scanning is performed. This is repeated, and the entire screen 13 is scanned two-dimensionally.

The screen 13 is disposed on the optical path from the light source unit 11 to the windshield 201. The screen 13 is fixed so as not to move on the optical path. An image is formed on the screen 13 by scanning of the scanning unit 12. The screen 13 is a transmissive screen, and is specifically a rectangular plate-shaped ground glass.

The first mirror 14 and the second mirror 15 are optical systems (hereinafter referred to as the optical system) disposed on the optical path in order to display an image formed on the screen 13 by scanning by the scanning unit 12 as a virtual image I1 on the windshield 201. The first mirror 14 and the second mirror 15 are also referred to as virtual image optical systems). The windshield 201 is positioned above such a virtual image optical system (the first mirror 14 and the second mirror 15). The first mirror 14 and the second mirror 15 are fixed so as not to move on the optical path.

The first mirror 14 is a reflecting member that projects (reflects) an image formed on the screen 13 onto the second mirror 15. The first mirror 14 is specifically a convex mirror, but may be a plane mirror. When the first mirror 14 is a convex mirror, the intermediate image can have a wider angle of view and the optical path length can be shortened, so that the display device 10 can be downsized. The first mirror 14 may be omitted. In this case, the image formed on the screen 13 is projected (reflected) directly onto the windshield 201 by the second mirror 15.

The second mirror 15 is a reflecting member that projects (reflects) the image projected (reflected) by the first mirror 14 onto the windshield 201. Specifically, the second mirror 15 is a concave mirror, and a virtual image I1 in which an image formed on the screen 13 is enlarged is displayed by reflecting light on the concave surface. In other words, the second mirror is a concave mirror for enlarging and displaying the image formed on the screen 13 as a virtual image I0 on the windshield 201.

In addition, the optical member which comprises a virtual image optical system is not specifically limited. For example, the virtual image optical system may include a lens in addition to the mirror.

[Distortion caused by scanning]
Next, image distortion caused by scanning by the scanning unit 12 will be described. FIG. 5 is a schematic diagram showing distortion of an image formed on the screen 13 caused by scanning of the scanning unit 12.

In general, the larger the incident angle of laser light from the light source unit 11 to the scanning unit 12, the greater the distortion. That is, since the distortion increases as the scanning unit 12 scans the edge of the image, both end portions in the horizontal direction of the image formed on the screen 13 are distorted upward in the vertical direction. Then, the same distortion occurs in the virtual image I1.

In the display device 10, such distortion is reduced by the arrangement (posture) of the screen 13, the arrangement (posture) of the first mirror 14, or the arrangement (posture) of the second mirror 15. That is, at least one of the screen 13 and the virtual image optical system is arranged so as to reduce distortion of the virtual image I1 caused by scanning. Hereinafter, the arrangement of these components for reducing distortion will be described.

[Screen layout]
First, an example of reducing distortion by arranging the screen 13 will be described. FIG. 6 is a schematic diagram for explaining an example in which distortion is reduced by the arrangement of the screen 13.

Suppose that the incident angle of the laser beam incident on the screen 13 from the scanning unit 12 is θ1 when the scanning unit 12 is scanning the end where distortion occurs (the end in the vertical direction of the image). At this time, when distortion as shown in FIG. 5 occurs, the posture of the screen 13 is indicated by a broken line so that the incident angle to the screen 13 becomes θ2 smaller than θ1 when the scanning unit 12 scans the end. Tilt to the position shown at 13a. Thereby, distortion can be reduced.

For example, θ2 is set so that a distortion amount that is the same as the distortion amount generated by the scanning of the scanning unit 12 is generated and the distortion is generated in a direction opposite to the direction of the distortion generated by the scanning of the scanning unit 12. Thereby, the distortion caused by the scanning of the scanning unit 12 can be canceled by the arrangement (posture) of the screen 13 and the distortion can be eliminated.

As described above, the screen 13 may be arranged so that the incident angle of the light to the screen 13 is an angle that reduces the distortion of the virtual image I1 caused by the scanning of the scanning unit 12.

Further, the direction of distortion can be changed by arranging the light source unit 11 at a position 11a indicated by a broken line in FIG. 6 and changing the sign of the incident angle to the scanning unit 12. That is, if distortion occurs when the light source unit 11 is arranged as shown in FIG. 6, the distortion may be reduced by changing the position of the light source unit 11 to the position 11a.

[Arrangement of first mirror]
Next, an example in which distortion is reduced by the arrangement of the first mirror 14 will be described. FIG. 7 is a schematic diagram for explaining an example in which distortion is reduced by the arrangement of the first mirror 14.

When light is incident on the first mirror 14 at an incident angle θ3, if the distortion shown in FIG. 5 occurs, the first mirror 14 is indicated by a broken line 14a so that the incident angle becomes θ4 larger than θ3. Tilt to posture. Thereby, the incident angle of the light to the 2nd mirror 15 becomes large. Then, distortion occurs in a direction opposite to the distortion shown in FIG. 5, so that distortion generated by scanning of the scanning unit 12 can be reduced (cancelled).

For example, θ4 is set such that the same distortion amount as that generated by the scanning of the scanning unit 12 occurs, and distortion occurs in the direction opposite to the direction of distortion generated by the scanning of the scanning unit 12. Thereby, the distortion caused by the scanning of the scanning unit 12 can be canceled by the arrangement (posture) of the first mirror 14 and the distortion can be eliminated.

Also, there are cases where distortion can be reduced depending on the mounting direction of the first mirror 14. For example, as shown in FIG. 7, it is assumed that distortion occurs when one end 14b of the first mirror 14 is positioned on the upper side and the other end 14c of the first mirror 14 is positioned on the lower side. In this case, distortion may be reduced by changing the attachment of the first mirror 14 so that the one end 14b of the first mirror 14 is on the lower side and the other end 14c of the first mirror 14 is on the upper side. In this case, distortion is reduced by the aberration of the first mirror 14.

As described above, the distortion caused by the scanning of the scanning unit 12 may be reduced depending on the mounting direction of the first mirror 14.

[Arrangement of second mirror]
Next, an example in which distortion is reduced by the arrangement of the second mirror 15 will be described. FIG. 8 is a schematic diagram for explaining an example in which distortion is reduced by the arrangement of the second mirror 15.

When light is incident on the second mirror 15 at an incident angle θ5, if the distortion shown in FIG. 5 occurs, the posture of the second mirror 15 indicated by a broken line 15a so that the incident angle becomes θ6 larger than θ5. Tilt up. As a result, distortion occurs in a direction opposite to the distortion shown in FIG. 5, so that distortion caused by scanning of the scanning unit 12 can be reduced (cancelled).

For example, θ6 is set so that the same distortion amount as that generated by the scanning of the scanning unit 12 occurs, and the distortion occurs in a direction opposite to the direction of distortion generated by the scanning of the scanning unit 12. Thereby, the distortion caused by the scanning of the scanning unit 12 can be canceled by the arrangement (posture) of the second mirror 15 and the distortion can be eliminated.

As described above, the second mirror 15 may be arranged so that the incident angle of the light to the second mirror 15 is an angle that reduces the distortion of the virtual image I1 caused by the scanning of the scanning unit 12.

Also, there are cases where distortion can be reduced depending on the mounting direction of the second mirror 15. For example, as shown in FIG. 9, the distortion may be reduced by arranging the optical system so that the light reflection direction by the second mirror 15 is changed. FIG. 9 is a schematic diagram for explaining an example in which distortion is reduced depending on the mounting direction of the second mirror 15.

9 and FIG. 4 described above, the arrangement of the optical system in the display device 10 is substantially symmetric in the left-right direction (the front-rear direction as viewed from the user). For example, in the example of FIG. 9, unlike FIG. 4, light is incident on the second mirror 15 not from the rear (user side) but from the front (virtual image I1 side). When the mounting direction of the second mirror 15 is changed as shown in FIGS. 4 to 9, distortion may be reduced due to the aberration of the second mirror 15.

Thus, the distortion caused by the scanning of the scanning unit 12 may be reduced depending on the mounting direction of the second mirror 15.

Note that the distortion caused by the scanning of the scanning unit 12 may be reduced depending on the mounting direction of the first mirror 14. However, in the display device 10, since the surface curvature of the second mirror 15 is larger than that of the first mirror 14, the distortion can be more effectively reduced depending on the mounting direction of the second mirror 15.

[Reducing distortion using other optical systems]
The virtual image optical system only needs to reduce distortion caused by scanning of the scanning unit 12 in the entire virtual image optical system. That is, even if one optical component included in the virtual image optical system is arranged so as not to reduce (increase or maintain) the distortion caused by the scanning of the scanning unit 12, other optical components included in the virtual image optical system By arranging so as to reduce the distortion caused by the scanning of the scanning unit 12, it is only necessary to reduce the distortion caused by the scanning of the scanning unit 12 as the entire virtual image optical system. All of the optical components included in the virtual image optical system may be arranged so as to reduce distortion caused by scanning of the scanning unit 12.

Further, the virtual image optical system may include an optical member other than the mirror. For example, the virtual image optical system may include a lens. The lens is, for example, a lens dedicated to distortion correction. Such a lens may reduce distortion caused by scanning of the scanning unit 12.

(Other embodiments)
Although the embodiment has been described above, the present invention is not limited to the above embodiment.

For example, the display device according to the above embodiment may be mounted on a mobile device other than a vehicle. The display device may be mounted on, for example, an aircraft or a ship. Further, the present invention may be realized as a mobile device other than such a vehicle.

Also, the general or specific aspect of the present invention may be realized as a system, an apparatus, a method, or the like. In addition, general or specific aspects of the present invention may be realized by any combination of systems, apparatuses, and methods.

For example, the present invention may be realized as a mobile device including the display device of the above-described embodiment. Further, the present invention may be realized as a method for manufacturing or designing a display device. In such a manufacturing method or design method, in the manufacture or design of the display device according to the above-described embodiment, the step of arranging at least one of the screen and the optical system so as to reduce the distortion of the virtual image caused by the scanning of the scanning unit. including.

Although the embodiment has been described above, the present invention is not limited to this embodiment. Unless it deviates from the gist of the present invention, various modifications conceived by those skilled in the art have been made in this embodiment, and forms constructed by combining components in different embodiments are also within the scope of one or more aspects. May be included.

The present invention can be used for a display device that displays a virtual image using a display medium. For example, the present invention can be used for a vehicle HUD that displays a virtual image using a windshield as a display medium.

DESCRIPTION OF SYMBOLS 10 Display apparatus 11 Light source part 11a Position 12 Scan part 13

Screen

13a, 14a, 15a Broken line 14 1st mirror 14b One end 14c The other end 15 Second mirror 201 Windshield 202 Bonnet 300 Vehicle 301 Dashboard D1 area | region I0, I1 Virtual image P1- P6 image

Claims

A display device that displays a virtual image using a display medium,
A light source unit;
A screen disposed on an optical path from the light source unit to the display medium;
A scanning unit that performs scanning on the screen using light emitted from the light source unit;
An optical system disposed on the optical path in order to display the image formed on the screen by the scanning as the virtual image on the display medium,
At least one of the screen and the optical system is disposed so as to reduce distortion of the virtual image caused by the scanning.
The optical system includes a mirror,
The display device according to claim 1, wherein the mirror is arranged such that an incident angle of light to the mirror is an angle that reduces distortion of the virtual image caused by the scanning.
The display device according to claim 2, wherein the mirror is a concave mirror for enlarging and displaying the image as the virtual image on the display medium.
The display device according to any one of claims 1 to 3, wherein the screen is arranged such that an incident angle of light to the screen is an angle that reduces distortion of the virtual image caused by the scanning.
The display device according to any one of claims 1 to 4, wherein the scanning unit is a micro electro mechanical system (MEMS) mirror.
The display device according to any one of claims 1 to 5, wherein the display medium is a windshield of a vehicle.