JP2017015805A - Virtual image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a virtual image display device capable of ensuring a longer optical path length from an image display screen to a projection mirror, compared to conventional devices having the same volume, and achieving reduction in size of the device.SOLUTION: An image is projected from a projector 4 onto a screen 5 to produce a virtual image 10 of the image visually recognized by a crew 9 of a vehicle. A half mirror region 23 comprising a half mirror is disposed in at least a part of a concave mirror 7, and the half mirror region 23 is located on an optical path connecting the screen 5 and a reflection mirror 6. An optical path 22 is configured in such a manner that light on the optical path coming from the screen 5 is transmitted from the convex side of the concave mirror 7 through the half mirror region 23 to reach the reflection mirror 6, and further, is reflected by the reflection mirror 6 to reach the concave side of the concave mirror 7.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a virtual image display device that displays a virtual image visually recognized by a user.

  Conventionally, various means have been used as information providing means for providing driving information such as route guidance and obstacle warnings to passengers of moving bodies such as vehicles. For example, display on a liquid crystal display installed on a moving body, sound output from a speaker, and the like. In recent years, as one of such information providing means, a head-up display device (hereinafter referred to as HUD) is used in a space different from a position where an image is actually displayed using an illusion of human eyes. There is a virtual image display device for visually recognizing an image.

  Here, since such a virtual image display device needs to be installed in an empty space of a moving body, it is desirable to make it as small as possible. However, in order to make the virtual image visible at a position some distance away from the user, the optical path length connecting the image display surface (for example, screen or display) displaying the image inside the apparatus to the projection mirror (for example concave mirror) is longer than a certain distance. It was necessary to ensure, and it was difficult to realize downsizing. Therefore, for example, in Japanese Patent Application Laid-Open No. 2002-52955, it is possible to secure a long optical path length in a narrower space than in the past by arranging a transflective mirror between the display source and the magnifying reflector. The technology to do is disclosed.

JP 2002-52955 A (page 4-5, FIG. 1)

  However, in the technique of Patent Document 1, the optical path connecting the display source that is the video display surface and the magnifying reflector that is the projection mirror is reflected by the transflective mirror disposed between the display source and the magnifying reflector. Instead, it only passes through the transflective mirror. In other words, the optical path connecting the display source and the magnifying reflecting mirror is simply a line segment connecting the display source and the magnifying reflecting mirror, and it was not possible to secure a long optical path length by using the semi-transmissive reflecting mirror. . Therefore, the above-described problem of downsizing the device has not been solved.

  The present invention has been made to solve the above-described problems in the prior art, and by making at least a part of the projection mirror a half mirror, the optical path length connecting the image display surface to the projection mirror is compared with the conventional one. An object of the present invention is to provide a virtual image display device that can be secured for a longer time in devices of the same volume and realizes downsizing of the device.

In order to achieve the above object, a virtual image display device according to the present invention displays a video using a light from a light source, and reflects the video displayed on the video display surface to allow a user to visually recognize the video. And a projection mirror that generates a virtual image of the video, and is disposed between the video display surface and the projection mirror along an optical path connecting the video display surface and the projection mirror, and is arranged in a first direction from the video display surface. A reflection mirror that changes the optical path incident on the projection mirror in a second direction toward the projection mirror, and at least a part of the projection mirror includes a half mirror region composed of a half mirror, and the video display surface; The half mirror region is located on an optical path connecting to the reflection mirror, and the optical path incident in the first direction from the image display surface passes through the half mirror region and reaches the reflection mirror.
The “optical path” refers to a path through which light output from a light source (for example, a projector, a backlight of a liquid crystal panel, a light emitting element of an organic EL display, etc.) used for displaying an image on an image display surface. For example, the optical path connecting the image display surface to the projection mirror is a light path from the image display surface to the projection mirror, and is basically the image display surface (particularly the position where the image is displayed). This is a path connecting the projector to the projection mirror with a straight line. However, when means (for example, a mirror or a lens) for changing the traveling direction of light by refracting or reflecting light is disposed between the image display surface and the projection mirror, the means makes a predetermined angle. This applies to refracted or reflected paths.
Further, the “half mirror” does not necessarily have the same transmittance and reflectance, and may be a member (beam splitter) that transmits a part of incident light and reflects a part thereof.

  According to the virtual image display device of the present invention having the above-described configuration, at least a part of the projection mirror is made into a half mirror, the half mirror region is positioned on the optical path connecting the image display surface and the reflection mirror, and is incident from the image display surface. The optical path that passes through the half mirror area reaches the reflection mirror, is reflected by the reflection mirror and returned to the projection mirror, and is further reflected by the projection mirror so that the user can visually recognize it. It is possible to secure a longer optical path length in a device having the same volume as compared with the conventional one. As a result, it is possible to reduce the size of the apparatus.

It is the figure which showed the installation aspect to the vehicle of HUD which concerns on this embodiment. It is the figure which showed the internal structure of HUD which concerns on this embodiment. It is the figure which showed the structure of the projector. It is the figure which showed the screen. It is the figure which showed the reflective mirror. It is a front view of a concave mirror. It is the figure which showed the optical path which connects a screen and a concave mirror. It is a figure explaining the production | generation distance of a virtual image. It is the figure which showed the positional relationship of each member which comprises the passenger | crew of a vehicle and HUD. It is the block diagram which showed the structure of HUD which concerns on this embodiment. It is the figure which showed an example of the virtual image visually recognizable from the passenger | crew of a vehicle.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a virtual image display device according to the invention will be described in detail with reference to the drawings with regard to an embodiment in which the virtual image display device is embodied in a head-up display device mounted on a vehicle.

  First, the configuration of a head-up display device (hereinafter referred to as HUD) 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram showing an installation mode of the HUD 1 according to the present embodiment on the vehicle 2.

  As shown in FIG. 1, the HUD 1 is installed inside the dashboard 3 of the vehicle 2, and includes a projector 4 and a screen 5 on which an image from the projector 4 is projected. Then, the image projected on the screen 5 is reflected on the front window 8 in front of the driver's seat through the reflection mirror 6 and the concave mirror 7 provided in the HUD 1 as will be described later so that the passenger 9 of the vehicle 2 can visually recognize the image. It is configured. The image projected on the screen 5 includes information related to the vehicle 2 and various information used for assisting the driving of the occupant 9. For example, warnings for obstacles (other vehicles and pedestrians), guidance information set by the navigation device, guidance information based on the guidance route (arrows indicating right and left turn directions, etc.), warnings to be displayed on the road surface (attention to rear-end collision, speed limit, etc.) ), Current vehicle speed, information signs, map images, traffic information, news, weather forecast, time, connected smartphone screen, TV program, and the like.

  Further, in the HUD 1 of the present embodiment, when the occupant 9 visually recognizes the image projected on the screen 5 by reflecting the front window 8, the occupant 9 is not at the position of the front window 8 but at the tip of the front window 8. An image projected on the screen 5 at a distant position is configured to be visually recognized as a virtual image 10. The virtual image 10 that can be seen by the occupant 9 is an image projected on the screen 5, but the vertical direction and the horizontal direction may be reversed through the concave mirror 7 and the reflective mirror 6. It is necessary to project an image on the screen 5. Further, the size is also changed through the Fresnel lens and the concave mirror 7.

  Here, regarding the position where the virtual image 10 is generated, more specifically, the distance L from the occupant 9 to the virtual image 10 (hereinafter referred to as the generation distance) L, the curvature of the concave mirror 7 and Fresnel lens provided in the HUD 1, the screen 5 and the concave mirror 7 It is possible to set appropriately depending on the relative position and the like. For example, if the curvature of the concave mirror 7 or the Fresnel lens is fixed, the generation distance L is determined by the distance (optical path length) along the optical path from the position where the image is displayed on the screen 5 to the concave mirror 7. For example, the optical path length is set so that the generation distance L is 40 m.

  Here, the HUD 1 of the present embodiment forms a part of the concave mirror 7 as a half mirror as will be described later, whereby a distance (optical path length) along the optical path from the position where the image is displayed on the screen 5 to the concave mirror 7. Can be secured longer than the volume of the apparatus.

  A front camera 11 is installed above the front bumper of the vehicle, behind the rearview mirror, and the like. The front camera 11 is an imaging device configured by a camera using a solid-state imaging device such as a CCD, for example, and is installed with the optical axis direction facing forward in the traveling direction of the vehicle. Then, by performing image processing on the captured image captured by the front camera 11, the situation of the front environment (that is, the environment in which the virtual image 10 is superimposed) that is visually recognized by the occupant 9 through the front window 8 is detected. Is done. A sensor such as a millimeter wave radar may be used instead of the front camera 11.

  Next, a more specific configuration of the HUD 1 will be described with reference to FIG. FIG. 2 is a diagram showing an internal configuration of the HUD 1 according to the present embodiment.

  As shown in FIG. 2, the HUD 1 basically includes a projector 4, a screen 5, a reflection mirror 6, a concave mirror 7, an adjustment mirror 14, a cover glass 15, a control circuit unit 16, and a CAN interface 17. It is configured.

  Here, the projector 4 is an image projection apparatus using an LED light source, a lamp light source, or a laser light source as a light source, and is, for example, a laser scanning projector. The projector 4 may be a DLP projector, a liquid crystal projector, or an LCOS projector. When a projector other than the laser scanning projector is used, it is necessary to separately arrange a projection lens for the projector 4.

  FIG. 3 is a diagram showing the configuration of the projector 4. As shown in FIG. 3, the projector 4 includes a laser light source 18 inside. For example, in a laser scanning projector, the laser light output from the light source 18 is reflected by the MEMS mirror 19 and scanned on the screen 5. As a result, a desired image is projected onto the screen 5.

  On the other hand, the screen 5 is a projection medium on which an image projected from the projector 4 is projected. For example, a transmissive screen made of a diffusing plate such as ground glass or a microlens array is used. Here, FIG. 4 is a diagram showing the screen 5.

  As shown in FIG. 4, the screen 5 has a projection area 21 as a video projection surface on which a video is projected, and a video projected from the projector 4 using the light from the light source 18 is displayed. That is, the screen 5 corresponds to a video display surface on which video is displayed. In addition, the passenger | crew 9 will visually recognize the image | video projected by the projector 4 from the opposite side to a projection side.

  Further, instead of the projector 4 and the screen 5, a liquid crystal display, an organic EL display, or the like may be used as means for displaying an image to be visually recognized by the occupant 9. In that case, the backlight of the liquid crystal display or the light emitting element of the organic EL display corresponds to the light source, and the surface on which the image is displayed in the liquid crystal display or the organic EL display corresponds to the liquid crystal display surface.

  The reflecting mirror 6 is disposed between the screen 5 and the concave mirror 7 along the optical path 22 connecting the screen 5 and the concave mirror 7, and the optical path 22 incident in the first direction from the screen 5 is directed to the concave mirror 7. The light reflecting means changes in two directions. In particular, in the present embodiment, the reflection mirror 6 is disposed so as to face the screen 5 and be substantially parallel. As a result, the optical path 22 incident from the screen 5 in the first direction passes through the concave mirror 7 and reaches the reflection mirror 6 as will be described later. It becomes possible to change the optical path 22 in the second direction.

  On the other hand, the concave mirror 7 is a projection mirror that generates a virtual image 10 (see FIG. 1) in front of the occupant 9 by enlarging and reflecting the image displayed on the screen 5 and causing the occupant 9 to visually recognize the image. As the concave mirror 7, a spherical concave mirror, an aspheric concave mirror, or a free-form curved mirror for correcting distortion of a projected image is used.

  Here, FIG. 6 is a front view of the concave mirror 7. As shown in FIG. 6, the concave mirror 7 is provided with a half mirror region 23 formed of a half mirror in part. The half mirror region 23 is, for example, a region composed of a half mirror having the same transmittance and reflectance. However, the half mirror does not necessarily have the same transmittance and reflectance, and transmits a part of incident light. Any member that reflects part of the beam (beam splitter) may be used. For example, the half mirror region 23 may be a region having a transmittance of 40%, a reflectance of 60%, a transmittance of 60%, and a reflectance of 40%. On the other hand, the region other than the half mirror region 23 is configured by a mirror having a higher reflectance than the transmittance (for example, a total reflection mirror having a transmittance of 0% and a reflectance of 100%). The region other than the half mirror region 23 does not necessarily have to be configured by a total reflection mirror, but a clearer virtual image 10 can be generated by using a mirror having a high reflectance.

  In addition, the half mirror region 23 is provided in a region around the edge in the direction opposite to the direction in which the occupant 9 has a viewpoint. For example, in this embodiment, as shown in FIG. 2, the occupant 9 visually recognizes an image from the cover glass 15 on the upper surface of the apparatus, so that the half mirror region 23 is provided at the lower edge of the concave mirror 7. Further, the size of the half mirror region 23 is appropriately set based on the size of the screen 5. Specifically, the size is such that all the optical paths incident from the screen 5 arranged on the back side (convex side) of the concave mirror 7 can be transmitted. That is, the larger the screen 5 is, the larger the size of the half mirror area 23 needs to be. Further, in order to improve the visibility of the virtual image 10, it is desirable that the half mirror region 23 is as small as possible. Therefore, the size of the half mirror region 23 is set to the minimum size that can transmit all the light paths incident from the screen 5.

  Further, as shown in FIG. 7, the screen 5, the concave mirror 7 and the reflection mirror 6 are arranged in the same straight line. The half mirror region 23 is positioned on the optical path connecting the screen 5 and the reflecting mirror 6, and the optical path 22 incident from the screen 5 in the first direction passes through the half mirror region 23 from the convex side of the concave mirror 7. Each member is arranged so as to reach the reflecting mirror 6 and further reflected by the reflecting mirror 6 to reach the concave surface side of the concave mirror 7. Therefore, the optical path length X of the optical path 22 connecting the screen 5 to the concave mirror 7 can be secured longer than that of a conventional product having the same device volume.

  Here, the position where the virtual image 10 of the image projected on the screen 5 is generated, specifically, the generation distance L which is the distance from the occupant 9 to the virtual image 10 shown in FIG. 8 is from the screen 5 shown in FIG. 7 depends on the optical path length X of the optical path 22 connecting up to 7. In this embodiment, by providing the half mirror region 23 in a part of the concave mirror 7, the optical path length X can be secured longer than the volume of the apparatus, so the generation distance L can be reduced even if the apparatus is downsized compared to the conventional apparatus. The virtual image 10 can be set long and the virtual image 10 can be generated at an appropriate position away from the occupant 9 by a certain distance or more.

  Further, the screen 5 is arranged on the back side (convex surface side) of the concave mirror 7 at a predetermined distance from the concave mirror 7. In particular, the screen 5 does not overlap with a range in which the occupant 9 can see through the half mirror region 23. Placed in. Thereby, it is possible to prevent the occupant 9 from viewing an unnecessary image.

  From the viewpoint of reducing the size of the apparatus, it is desirable to arrange the screen 5 as close as possible to the concave mirror 7. Therefore, as shown in FIG. 9, the first end P <b> 1 that is the point farthest from the light source 18 in the area where the image of the front window 8 is reflected, and the first end of the half mirror region 23 of the concave mirror 7. A second end P2 that is the point closest to the part P1 is set. The screen 5 is arranged at a position where the lower end is in contact with the straight line Y connecting the first end P1 and the second end P2. As a result, the screen 5 is not visually recognized by the occupant 9 through the half mirror region 23, and the screen 5 can be disposed as close to the concave mirror 7 as possible.

  On the other hand, the adjustment mirror 14 is light reflecting means for changing the optical path 22 in the HUD 1 by reflecting light from the light source 18 output from the projector 4 in the direction of the screen 5 as shown in FIG.

  The cover glass 15 is a transmissive plate-like member disposed on the upper surface of the HUD 1. The image displayed on the screen 5 is reflected by the concave mirror 7 and is visually recognized by the occupant 9 through the cover glass 15. Note that a Fresnel lens may be used as the cover glass 15. When a Fresnel lens is used as the cover glass 15, a flat mirror can be used instead of the concave mirror 7.

  The control circuit unit 16 is an electronic control unit that controls the entire HUD 1. Here, FIG. 10 is a block diagram showing a configuration of the HUD 1 according to the present embodiment.

  As shown in FIG. 10, the control circuit unit 16 generates a virtual image in addition to the CPU 31 as the arithmetic device and the control device, the RAM 32 used as a working memory when the CPU 31 performs various arithmetic processes, and a control program. And an internal storage device such as a flash memory 34 for storing a program read from the ROM 33. The control circuit unit 16 is connected to the projector 4 and performs drive control of the projector 4.

  The CAN (controller area network) interface 17 is an interface for inputting / outputting data to / from CAN, which is a vehicle-mounted network standard that performs multiplex communication between various vehicle-mounted devices and vehicle equipment control devices installed in the vehicle. It is. The HUD 1 is connected to a control device (for example, the navigation device 48, the AV device 49, etc.) of various vehicle-mounted devices and vehicle equipment via the CAN so as to be able to communicate with each other. Thereby, the HUD 1 is configured to be able to project information acquired from the navigation device 48, the AV device 49, and the like.

  The video projected by the projector 4 includes information related to the vehicle 2 and various information used for assisting the driving of the occupant 9. For example, a warning for an obstacle (another vehicle or a pedestrian), a guidance route (scheduled travel route) set by the navigation device 48, guidance information based on the guidance route (such as an arrow indicating the traveling direction of the vehicle), and a warning displayed on the road surface (Notes of rear-end collision, speed limit, etc.), current vehicle speed, information signs, map images, traffic information, news, weather forecast, time, connected smartphone screen, TV screen, etc. In particular, in the present embodiment, a video for generating a virtual image for guidance is output by superimposing it on the surrounding environment and causing the occupant 9 to visually recognize it. For example, an arrow indicating the traveling direction of the vehicle, which is guidance information based on the guidance route set by the navigation device 48, is output.

  As a result, for example, when a guidance route is set in the navigation device 48, and there is no intersection to be turned right or left in front of the vehicle in the traveling direction, the vehicle travels straight ahead in the traveling direction of the vehicle as shown in FIG. A virtual image 10 of an arrow indicating the direction is generated. The virtual image 10 indicated by the arrow is desirably generated so that the lower end of the virtual image 10 is positioned on the ground, more specifically, the lower end of the virtual image 10 is positioned on the ground. Note that when an intersection to be turned right or left approaches in front of the traveling direction of the vehicle, a virtual image 10 of an arrow indicating a right / left turn is generated instead of an arrow indicating a straight traveling direction. As a result, a virtual image of an arrow indicating the traveling direction of the vehicle is generated in the vicinity of 40 m ahead of the occupant 9, and the occupant 9 can minimize the movement of the line of sight when viewing the virtual image.

  As described above in detail, according to the HUD 1 according to the present embodiment, a video is projected from the projector 4 onto the screen 5, and the virtual image 10 of the video that the vehicle occupant 9 visually recognizes is generated. In addition, a half mirror region 23 composed of a half mirror is provided on at least a part of the concave mirror 7, the half mirror region 23 is located on the optical path connecting the screen 5 and the reflection mirror 6, and the optical path 22 incident from the screen 5 is Since the concave mirror 7 is configured so as to pass through the half mirror region 23 from the convex surface side to the reflective mirror 6 and further reflected by the reflective mirror 6 to reach the concave surface side of the concave mirror 7, It is possible to ensure a longer optical path length connecting up to 7 in a device having the same volume as compared with the conventional one. As a result, it is possible to reduce the size of the apparatus.

Note that the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the scope of the present invention.
For example, in the present embodiment, the virtual image is generated in front of the front window 8 of the vehicle 2 by the HUD 1, but the virtual image may be generated in front of a window other than the front window 8. Further, the object to be reflected by the HUD 1 may be a visor (combiner) installed around the front window 8 instead of the front window 8 itself.

  In the present embodiment, the HUD 1 is installed on the vehicle 2. However, the HUD 1 may be installed on a moving body other than the vehicle 2. For example, it can be installed on a ship or an aircraft. Moreover, you may install in the ride type attraction installed in an amusement facility. In that case, a virtual image can be generated around the ride so that the rider can visually recognize the virtual image.

  In the present embodiment, only a partial region of the concave mirror 7 is used as the half mirror region 23, but the entire region of the concave mirror 7 may be used as the half mirror region 23. Even in such a case, the optical path length connecting the screen 5 to the concave mirror 7 can be ensured longer in an apparatus having the same volume as compared with the prior art.

  In the present embodiment, the half mirror region 23 is provided at the lower edge of the concave mirror 7, but may be provided at the center, upper edge, left and right edges, etc. of the concave mirror 7. Regardless of the position of the half mirror region 23, it is desirable to arrange the screen 5 at a position that does not overlap with a range where the occupant 9 can see through the half mirror region 23.

  In this embodiment, a laser scanning projector that does not require a projection lens is used, but a projector other than the laser scanning projector (for example, a DLP projector, a liquid crystal projector, or an LCOS projector) may be used.

  In the present embodiment, the CPU 31 of the HUD 1 is configured to execute each step of the processing program for generating a virtual image. However, an in-vehicle device (for example, the navigation device 48) other than the HUD 1 or an ECU that controls the vehicle is one. It is good also as a structure which performs a part or all process.

  Moreover, although the embodiment which actualized the virtual image display device according to the present invention has been described above, the virtual image display device can also have the following configuration, and in that case, the following effects can be obtained.

For example, the first configuration is as follows.
An image display surface (5) for displaying an image using light from the light source (18), and a projection for generating a virtual image of the image by reflecting the image displayed on the image display surface and allowing the user to visually recognize the image. The optical path that is disposed between the image display surface and the projection mirror along an optical path connecting the mirror (7) and the image display surface and the projection mirror, and is incident in the first direction from the image display surface. A reflection mirror (6) that changes in a second direction toward the projection mirror, and includes at least part of the projection mirror includes a half mirror region (23) composed of a half mirror, and the video display surface. The half mirror region is located on an optical path connecting to the reflection mirror, and the optical path incident in the first direction from the image display surface passes through the half mirror region and reaches the reflection mirror.
According to the virtual image display device having the above configuration, at least a part of the projection mirror is half mirrored, the half mirror region is positioned on the optical path connecting the video display surface and the reflection mirror, and the optical path incident from the video display surface is half. Since it passes through the mirror area and reaches the reflection mirror, it is reflected by the reflection mirror, returned to the projection mirror, and further reflected by the projection mirror to be visually recognized by the user, so that the optical path length from the image display surface to the projection mirror is set. It is possible to ensure a longer time in an apparatus having the same volume as compared with the prior art. As a result, it is possible to reduce the size of the apparatus.

The second configuration is as follows.
The video display surface (5), the projection mirror (7), and the reflection mirror (6) are arranged in the same straight line.
According to the virtual image display device having the above configuration, the image display surface, the projection mirror, and the reflection mirror are arranged in the same straight line, and the optical path length from the image display surface to the projection mirror is efficiently reduced by folding the optical path with the reflection mirror. It can be secured. Further, by arranging them in a straight line, a useless space is not formed in the apparatus, and the apparatus can be miniaturized as much as possible.

The third configuration is as follows.
A part of the projection mirror (7) is the half-mirror region (23), and a region other than the half-mirror region has a higher reflectance than the transmittance.
According to the virtual image display apparatus having the above-described configuration, it is possible to make the user visually recognize a clearer virtual image by increasing the reflectance as much as possible in other regions while securing the region through which the optical path is transmitted.

The fourth configuration is as follows.
In the projection mirror (7), an area around the edge in the direction opposite to the direction in which the user's viewpoint is located is defined as the half mirror area (23).
According to the virtual image display device having the above configuration, even when the projection mirror is disposed close to the video display surface, it is possible to prevent the user from seeing the video display surface through the half mirror region. . In addition, the video display surface can be arranged in the dead space of the projection mirror. That is, it is possible to reduce the size of the apparatus.

The fifth configuration is as follows.
The said video display surface (5) is arrange | positioned in the position which does not overlap with the range which the said user can permeate | transmit and see the said half mirror area | region (23).
According to the virtual image display device having the above configuration, it is possible to prevent the user from seeing the video display surface through the half mirror region. Therefore, it is possible to prevent the user from viewing unnecessary images and light sources.

The sixth configuration is as follows.
The image reflected by the projection mirror (7) is further reflected on the glass surface (8) and visually recognized by the user (9), thereby generating a virtual image (10) of the image forward in the line-of-sight direction of the glass surface. A first end portion that is the point farthest from the light source in an area where the image of the glass surface is reflected, and a point that is closest to the first end portion in a half mirror region of the projection mirror The video display surface (5) is arranged in contact with a straight line connecting the second end portion.
According to the virtual image display device having the above-described configuration, the video display surface is not visually recognized by the user through the half mirror region, and the video display surface can be arranged as close to the projection mirror as possible. It becomes possible. Therefore, the virtual image can be appropriately visually recognized by the user and the apparatus can be downsized.

DESCRIPTION OF SYMBOLS 1 Head up display apparatus 2 Vehicle 3 Dashboard 4 Projector 5 Screen 6 Reflection mirror 7 Concave mirror 8 Front window 9 Crew 10 Virtual image 22 Optical path 23 Half mirror area 31 CPU
32 RAM
33 ROM
34 Flash memory

Claims (6)

An image display surface for displaying an image using light from a light source;
A projection mirror that generates a virtual image of the image by reflecting the image displayed on the image display surface and allowing the user to visually recognize the image;
The optical path that is disposed between the video display surface and the projection mirror along an optical path that connects the video display surface and the projection mirror and that is incident in the first direction from the video display surface is directed to the projection mirror. A reflecting mirror that changes in the second direction,
At least a part of the projection mirror includes a half mirror region composed of a half mirror,
The half mirror region is located on an optical path connecting the image display surface and the reflection mirror, and the optical path incident in the first direction from the image display surface is transmitted through the half mirror region to the reflection mirror. A virtual image display device.   The virtual image display device according to claim 1, wherein the video display surface, the projection mirror, and the reflection mirror are arranged on the same straight line.   3. The virtual image display according to claim 1, wherein the projection mirror is configured by a mirror having a part of the half-mirror region and a region having a reflectance higher than a transmittance in a region other than the half-mirror region. apparatus.   4. The virtual image display device according to claim 1, wherein the projection mirror uses an area around an edge in a direction opposite to a direction in which the user's viewpoint is present as the half mirror area. 5.   5. The virtual image display device according to claim 1, wherein the video display surface is arranged at a position that does not overlap with a range that the user can visually recognize through the half mirror region. By further reflecting the image reflected by the projection mirror to the glass surface and visually recognizing it by the user, a virtual image of the image is generated forward in the line-of-sight direction of the glass surface,
The first end portion that is the point farthest from the light source in the area where the image of the glass surface is reflected, and the closest point to the first end portion in the half mirror region of the projection mirror The virtual image display device according to claim 5, wherein the video display surface is disposed in contact with a straight line connecting the second end portion.

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