JP2018077435A - Virtual image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a virtual image display device that enables a user to visually recognize a high-quality virtual image.SOLUTION: A reflection type polarizing plate 6 is arranged between a liquid crystal display 5 and a concave mirror 7 along a light path connecting the liquid crystal display 5 and concave mirror 7, and the angle of the concave mirror 7 and a video display area of the liquid crystal display 5 are adjusted according to the detected position of the eyes of a user, to control to maintain the relationship in which the direction of a path of light made incoming from the reflection type polarizing plate 6 to the concave mirror 7 is opposite to the direction of a path of light reflected on the concave mirror and directed toward the position of the eyes of the driver 9 irrespective of the position of the eyes of the user.SELECTED DRAWING: Figure 10

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 visually recognize the virtual image at a position some distance away from the user, it is necessary to secure a certain optical path length from the image display surface (for example, a screen or display) that displays the image to the concave mirror within a certain distance. It was difficult to achieve downsizing. Therefore, for example, in Japanese Patent Laid-Open No. 8-136856, it is possible to secure a long optical path length in a narrower space than in the past by arranging a cholesteric liquid crystal element between a liquid crystal display and a concave mirror and turning the optical path back. The technology to make is disclosed.

JP-A-8-136856 (FIG. 1)

  Here, in the virtual image display device, in order for the user to visually recognize a higher quality virtual image, it is important how the optical path is reflected by the concave mirror and directed to the user's eyes. That is, the position design of each member forming the optical path (for example, the liquid crystal display, the concave mirror and the cholesteric liquid crystal element in Patent Document 1) is very important.

  However, in the above-mentioned Patent Document 1, the position design of the liquid crystal display, the concave mirror, and the cholesteric liquid crystal element for improving the quality of the virtual image as described above has not been performed. As a result, the quality of the virtual image may be deteriorated depending on the position design of each member.

  In addition, since the position and angle of each member for improving the quality of the virtual image described above are determined by the relationship with the position of the user's eyes, if the position of the user's eyes changes, it is necessary to change it accordingly. However, in Patent Document 1, no means for changing the position and angle of the liquid crystal display, the concave mirror, and the cholesteric liquid crystal element has been provided. As a result, the quality of the virtual image may be deteriorated depending on the position of the user's eyes.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a virtual image display device that enables a user to visually recognize a high-quality virtual image.

In order to achieve the above object, a virtual image display device according to the present invention reflects an image display surface for displaying an image by outputting light having a first polarization direction, and the image displayed on the image display surface. And a concave mirror that allows the user to visually recognize the virtual image of the video, and is disposed between the video display surface and the concave mirror along an optical path that connects the video display surface and the concave mirror, and A reflective polarizing plate that reflects light having a first polarization direction and transmits light having a second polarization direction different from the first polarization direction, along an optical path connecting the image display surface and the concave mirror A polarization direction displacement member disposed between the reflective polarizing plate and the concave mirror and displacing the polarization direction of light from the first polarization direction to the second polarization direction, and with respect to the image display surface The Display area setting means for setting a video display area for displaying an image; and angle adjustment means for adjusting the angle of the concave mirror, and the reflective polarizing plate is incident in the first direction from the video display face The optical path is changed to the second direction toward the concave mirror, and the concave mirror transmits the optical path incident in the second direction from the reflective polarizing plate through the reflective polarizing plate toward the user's eye position. In the third direction, the display area setting means and the angle adjusting means set the video display area and set the angle of the concave mirror so that the second direction and the third direction are opposite to each other. adjust.
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 concave mirror is the light path from the image display surface to the concave mirror, and is basically projected from the image display surface (particularly the position where the image is displayed). This is a route connecting the mirrors with straight lines. However, when a 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 concave mirror, it is refracted at a predetermined angle by the means. Or the reflected path | route corresponds.
The “reverse direction” is not limited to a direction different by 180 degrees, but a direction having a certain range of width including a direction different by 180 degrees.

  According to the virtual image display device according to the present invention having the above-described configuration, the reflective polarizing plate is disposed between the image display surface and the concave mirror along the optical path, and the optical path is once reflected by the reflective polarizing plate into the concave mirror. Since the optical path reflected from the concave mirror is transmitted to the user through the reflective polarizing plate, the optical path length from the image display surface to the concave mirror is longer than that of the conventional device in the same volume. It can be secured. As a result, it is possible to reduce the size of the apparatus. In addition, since the direction of the optical path incident on the concave mirror from the reflective polarizing plate and the direction of the optical path reflected by the concave mirror toward the user's eyes are reversed, the quality of the virtual image can be improved. . For example, it becomes possible to make the user visually recognize a clearer and clearer virtual image. Furthermore, by adjusting the image display area with respect to the image display surface and the angle of the concave mirror, the relationship between the members in the reverse direction can be obtained regardless of the position of the user's eyes. This makes it possible to hold the image and prevent the quality of the virtual image from deteriorating.

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 optical path formed in HUD. It is the figure which showed the arrangement | positioning aspect of (lambda) / 4 wavelength plate. It is a figure explaining the production | generation distance of a virtual image. It is the block diagram which showed the structure of HUD which concerns on this embodiment. It is a flowchart of the virtual image generation processing program which concerns on this embodiment. It is the figure which showed the visually recognizable range. It is a figure explaining the adjustment process of the angle of a concave mirror. It is a figure explaining the setting process of the video display area of a liquid crystal display. 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 liquid crystal display 5 that displays an image therein. Then, the video displayed on the liquid crystal display 5 is reflected on the front window 8 in front of the driver's seat through the reflective polarizing plate 6 and the concave mirror 7 provided in the HUD 1 as will be described later, and visually recognized by the passenger 9 of the vehicle 2. It is configured to let you. The video displayed on the liquid crystal display 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 displayed on the liquid crystal display 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. The image displayed on the liquid crystal display 5 at a distant position is visually recognized as a virtual image 10. The virtual image 10 that can be seen by the occupant 9 is an image displayed on the liquid crystal display 5, but the vertical direction and the horizontal direction may be reversed through the reflective polarizing plate 6 and the concave mirror 7. It is necessary to display the video on the liquid crystal display 5 in consideration. In addition, the size is changed through the concave mirror 7.

  Here, regarding the position where the virtual image 10 is generated, more specifically, the distance from the occupant 9 to the virtual image 10 (hereinafter referred to as virtual image generation distance) L, the curvature of the concave mirror 7 included in the HUD 1, the liquid crystal display 5 and the concave mirror 7 It is possible to set as appropriate depending on the relative position of the. For example, if the curvature of the concave mirror 7 is fixed, the virtual image 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 liquid crystal display 5 to the concave mirror 7. For example, the optical path length is set so that the virtual image generation distance L is 40 m.

  Here, the HUD 1 of the present embodiment reflects the direction of the optical path incident on the concave mirror 7 from the reflective polarizing plate 6 and the concave mirror 7 with respect to the liquid crystal display 5, the reflective polarizing plate 6 and the concave mirror 7 as will be described later. Since the position is designed so that the direction of the optical path toward the user's eye is opposite, the quality of the virtual image 10 can be improved. For example, it is possible to make the user visually recognize a clearer and clearer virtual image 10. Further, by using the reflective polarizing plate 6, the distance (optical path length) along the optical path from the position where the image is displayed on the liquid crystal display 5 to the concave mirror 7 can be secured longer than the volume of the apparatus. doing.

  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.

  An in-vehicle camera 12 is installed on the upper surface of the dashboard 3. Here, the in-vehicle camera 12 uses a solid-state imaging device such as a CCD, for example, and is installed with the imaging direction facing the driver's seat as shown in FIG. Then, the face of the occupant 9 sitting in the driver's seat is imaged. The HUD 1 detects the position of the eyes of the occupant 9 from the captured image captured by the in-vehicle camera 12 as will be described later.

  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 is basically composed of a liquid crystal display 5, a reflective polarizing plate 6, a concave mirror 7, a λ / 4 wavelength plate 15, a control circuit unit 16, and a CAN interface 17. Yes.

  Here, the liquid crystal display 5 uses a backlight as a light source, and outputs only the light having a specific polarization direction out of the light from the backlight, thereby displaying an image on the image display surface provided on the front surface. This is a video display device having the function of Note that the liquid crystal display 5 can display an image only on an arbitrary partial area instead of the entire image display surface (that is, an output range of light from the light source is arbitrarily set). Moreover, as a backlight, CCFL (cold cathode tube) and white LED are used, for example. As a means for displaying an image, a combination of a liquid crystal projector and a screen may be used in addition to the liquid crystal display.

  The reflective polarizing plate 6 has a property of reflecting (non-transmitting) light having a specific first polarization direction and transmitting light having a second polarization direction different from the first polarization direction. It is a member. In the reflective polarizing plate 6 of this embodiment, the first polarization direction is designed to be the same as the polarization direction of the light output from the liquid crystal display 5, and the second polarization direction is relative to the first polarization direction. Thus, the polarization direction is designed to have a phase difference of λ / 2 (180 degrees) (that is, a direction orthogonal to the first polarization direction). The reflective polarizing plate 6 is disposed between the liquid crystal display 5 and the concave mirror 7 along an optical path 18 connecting the liquid crystal display 5 and the concave mirror 7. As shown in FIG. 3, the light path 18 incident in the first direction from the liquid crystal display 5 functions as a light reflecting means that changes in the second direction toward the concave mirror 7. On the other hand, since the light reflected to the concave mirror 7 passes through the λ / 4 wavelength plate 15 twice as will be described later, the polarization direction is finally changed to the second polarization direction. The light path 18 functions as a light transmission means. FIG. 3 is a schematic diagram showing the optical path 18 formed in the HUD 1.

  On the other hand, the concave mirror 7 is a projection mirror that generates a virtual image 10 (see FIG. 1) of the image in front of the occupant 9 by enlarging and reflecting the image displayed on the liquid crystal display 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.

  As shown in FIG. 3, the concave mirror 7 changes the optical path incident in the second direction from the reflective polarizing plate 6 to the third direction that passes through the reflective polarizing plate 6 and moves toward the user's eyes. In particular, in this embodiment, the angle of the concave mirror 7 can be adjusted by driving the concave mirror angle adjusting motor 19 on the back side of the concave mirror 7. Then, the control circuit unit 16 adjusts the angle of the concave mirror 7 and the area for displaying an image on the liquid crystal display 5 based on the position of the eyes of the occupant 9 detected by the in-vehicle camera 12 as will be described later. Control is performed so as to maintain a relationship in which the third direction is the opposite direction. The “reverse direction” is not limited to a direction different by 180 degrees, but a direction having a certain range of width including a direction different by 180 degrees. For example, the direction different from 175 degrees or 185 degrees is also set as the opposite direction.

  In the HUD 1 according to the present embodiment, the angle of the concave mirror 7 and the area in which the image is displayed on the liquid crystal display 5 are controlled, and the second direction that is the direction of the optical path 18 that enters the concave mirror 7 from the reflective polarizing plate 6. The quality of the virtual image 10 can be improved by reversing the third direction, which is the direction of the optical path 18 that is reflected by the concave mirror 7 and travels toward the eye of the occupant 9. For example, it becomes possible to make the occupant 9 visually recognize a clearer and clearer virtual image 10. Furthermore, it is possible to give a width to the virtual image generation distance L that improves the quality of the virtual image 10. Therefore, even if the setting of the virtual image generation distance L is changed, there is no need to newly redesign the position of each member, and the versatility of the design is improved. Details of the control of the concave mirror 7 and the liquid crystal display 5 will be described later.

  The λ / 4 wavelength plate 15 is a polarizing element having a flat plate shape that gives a phase difference of λ / 4 (90 degrees) with respect to the polarization direction of light passing therethrough. In the present embodiment, the concave mirror 7 is disposed separately between the reflective polarizing plate 6 and the concave mirror 7 along the optical path connecting the liquid crystal display 5 and the concave mirror 7. Therefore, as shown in FIG. 3, the light output from the liquid crystal display 5 first passes through the λ / 4 wavelength plate 15 while moving from the reflective polarizing plate 6 to the concave mirror 7. Then, the light passes through the λ / 4 wavelength plate 15 again while being reflected by the concave mirror 7 and moved to the reflective polarizing plate 6. As a result, a phase difference of λ / 2 (180 degrees) is given in increments of λ / 4 with respect to the polarization direction of light. Accordingly, at the stage of output from the liquid crystal display 5, the light polarization direction is the first polarization direction that is a reflection target (non-transmission target) in the reflective polarizing plate 6. By passing through the number of times, the reflective polarizing plate 6 is finally displaced in the second polarization direction to be transmitted.

  The λ / 4 wavelength plate 15 is disposed at an angle that is perpendicular to the optical path 18 that is basically transmitted. In the present embodiment, the position and angle are fixed, but the concave mirror 7 and the angle may be changed. Furthermore, the size includes all the light transmitted from the reflective polarizing plate 6 in the second direction and the light transmitted from the concave mirror 7 in the third direction, and the size is as small as possible. In particular, in this embodiment, the angle of the concave mirror 7 and the area for displaying an image on the liquid crystal display 5 are changed. Therefore, the size includes all of the transmitted light regardless of how the angle of the concave mirror 7 and the image display area are controlled. And

  Further, the λ / 4 wavelength plate 15 is arranged in a range that does not overlap the optical path 18 that connects the liquid crystal display 5 and the reflective polarizing plate 6 as shown in FIG. 4. In particular, in the present embodiment, the angle of the concave mirror 7 and the area for displaying an image on the liquid crystal display 5 are changed. Therefore, the liquid crystal display 5 and the reflective polarizing plate are controlled regardless of how the angle of the concave mirror 7 and the image display area are controlled. 6 is arranged at a position not overlapping with the optical path 18 connecting the

  Further, the position where the virtual image 10 of the image projected on the liquid crystal display 5 is generated, specifically, the virtual image generation distance L which is the distance from the passenger 9 to the virtual image 10 shown in FIG. 5 is the liquid crystal display 5 shown in FIG. Depends on the optical path length of the optical path 18 from the first to the concave mirror 7. In this embodiment, since the optical path length can be secured longer than the volume of the apparatus by providing the reflective polarizing plate 6, the virtual image generation distance L can be set longer even if the apparatus is downsized compared to the conventional apparatus. It is possible, and it becomes possible to generate the virtual image 10 at an appropriate position away from the occupant 9 by a certain distance or more.

  The control circuit unit 16 is an electronic control unit that controls the entire HUD 1. Here, FIG. 6 is a block diagram showing the configuration of the HUD 1 according to the present embodiment.

  As shown in FIG. 6, the control circuit unit 16 includes a CPU 31 as an arithmetic device and a control device, a RAM 32 used as a working memory when the CPU 31 performs various arithmetic processes, a control program, and a virtual image generation described later. A ROM 33 in which a processing program (see FIG. 7) and the like are recorded, and an internal storage device such as a flash memory 34 for storing a program read from the ROM 33 are provided. The control circuit unit 16 is connected to the liquid crystal display 5 and the concave mirror angle adjustment motor 19, respectively, and performs drive control of the liquid crystal display 5 and the motor.

  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 display information acquired from the navigation device 48, the AV device 49, and the like.

  Next, a virtual image generation processing program executed by the CPU 31 in the HUD 1 having the above configuration will be described with reference to FIG. FIG. 7 is a flowchart of the virtual image generation processing program according to this embodiment. Here, the virtual image generation processing program is a program that is executed after an ACC power supply (accessory power supply) of the vehicle is turned on, and generates a virtual image 10 that is visually recognized by an occupant 9 of the vehicle. Note that the program shown in the flowchart of FIG. 7 below is stored in the RAM 32 or ROM 33 provided in the HUD 1 and is executed by the CPU 31.

  First, in step (hereinafter abbreviated as S) 1 in the virtual image generation processing program, the CPU 31 sets a visible range (eye box). The visible range is the range of the eye position of the occupant 9 who can visually recognize the video displayed on the liquid crystal display 5 built in the HUD 1. Here, the HUD 1 has a configuration in which the image displayed on the liquid crystal display 5 inside is reflected on the front window 8 and visually recognized by the occupant 9 as described above. At the time of S1, the angle of the concave mirror 7 is set to an initial state, and an area for displaying an image on the liquid crystal display 5 (hereinafter referred to as an image display area) is also set to an initial state. In the initial state, as shown in FIG. 3, the second direction, which is the direction of the optical path 18 from the reflective polarizing plate 6 to the concave mirror 7, and the direction of the optical path 18 reflected by the concave mirror 7 toward the user's eyes. It is designed to be opposite to the third direction. The visible range is, for example, about 12 cm wide and 4 cm long.

  Subsequently, in S2, the CPU 31 captures the face of the occupant 9 of the vehicle seated in the driver's seat with the in-vehicle camera 12, and detects the current position of the left and right eyes of the occupant 9 by performing image processing on the captured image. To do. Since the method for detecting the eye position by the camera is already known, the details are omitted.

  Next, in S3, the CPU 31 determines whether or not the positions of both eyes of the occupant 9 detected in S2 are included in the visible range.

  If it is determined that both positions of the eyes of the occupant 9 detected in S2 are included in the visible range (S3: YES), the angle of the concave mirror 7 and the video display area are in the initial state. It is presumed that the virtual image 10 can be visually recognized as it is, and the process proceeds to S7.

  On the other hand, when it is determined that the position of at least one eye of the occupant 9 detected in S2 is not included in the visible range (S3: NO), the process proceeds to S4.

  In S4, the CPU 31 newly sets a visually recognizable area based on the position of the eyes of the occupant 9 detected in S2. The visible region is set to a range including at least both eyes of the occupant 9. For example, as shown in FIG. 8, the midpoint of both eyes is set to be the center of the visible range 51. The viewable range 51 set in S4 is stored in a storage medium such as the flash memory 34.

  Next, in S <b> 5, the CPU 31 drives the concave mirror angle adjustment motor 19 to adjust the angle of the concave mirror 7 to an angle having a vertical relationship with the center position of the visible range 51 as shown in FIG. 9. Specifically, the angle is adjusted so that the line connecting the center position of the visible range 51 and the center position of the concave mirror 7 becomes the normal line of the concave mirror 7. In other words, the optical path from the current eye position of the occupant 9 to the concave mirror 7 through the front window 8 and the optical path reflected by the concave mirror 7 are adjusted to be in an opposite direction.

  Subsequently, in S <b> 6, the CPU 31 sets a video display area for displaying video on the liquid crystal display 5. The video display area corresponds to the output area of the light source (backlight of the liquid crystal display 5). Specifically, as shown in FIG. 10, the second direction, which is the direction of the optical path from the reflective polarizing plate 6 to the concave mirror 7 whose angle has been adjusted in S 5, and the light reflected by the concave mirror 7 and passing through the front window 8. The video display area 52 is set so that the third direction, which is the direction of the optical path toward the user's eyes, is in the opposite direction. In setting the video display area 52, the position and angle of the reflective polarizing plate 6 are also considered.

A method for setting the video display area 52 will be described below.
First, the CPU 31 specifies an intersection point Q between the reflective polarizing plate 6 and a line drawn along the direction opposite to the third direction from the center position P of the concave mirror 7 after the angle adjustment of S5. Thereafter, an intersection X between the line PQ and the liquid crystal display 5 obtained by folding the line PQ at the same angle by the reflective polarizing plate 6 is specified. Then, an area centering on the intersection X is defined as a video display area 52. Note that the size of the video display area 52 is determined by the size of the virtual image 10 to be generated. The angle of the liquid crystal display 5 may be adjustable. For example, the angle of the liquid crystal display 5 may be adjusted so as to be perpendicular to the optical path.

  Then, in S5 and S6, as a result of adjusting the video display area of the liquid crystal display 5 and the angle of the concave mirror 7 corresponding to the current user's eye position, the viewable range 51 is changed to the current user's eye position. It is possible to change the range to include. Further, the second direction, which is the direction of the optical path 18 from the reflective polarizing plate 6 toward the concave mirror 7, and the third direction, which is the direction of the optical path 18 reflected by the concave mirror 7 toward the user's eyes, are reversed. This relationship is also maintained.

  Thereafter, in S7, the CPU 31 transmits a drive signal to the liquid crystal display 5, and starts displaying video in the video display area set in S6 in the liquid crystal display 5. The video displayed on the liquid crystal display 5 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 (planned 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 (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, the reflective polarizing plate 6 is disposed between the liquid crystal display 5 and the concave mirror 7 along the optical path connecting the liquid crystal display 5 and the concave mirror 7, and detection is performed. By adjusting the angle of the concave mirror 7 and the image display area of the liquid crystal display 5 according to the position of the user's eyes, the direction of the optical path incident on the concave mirror 7 from the reflective polarizing plate 6 regardless of the position of the user's eyes Since the relationship that the direction of the optical path reflected by the concave mirror and directed to the eye of the occupant 9 is opposite is maintained, the quality of the virtual image 10 can be improved. For example, it becomes possible to make the occupant 9 visually recognize a clearer and clearer virtual image 10. Furthermore, even if the occupant changes positions, for example, even if the position of the occupant's eyes is greatly displaced, the relationship between the members in the opposite directions can be maintained, and the quality of the virtual image can be prevented from deteriorating. In addition, the optical path length connecting the liquid crystal display 5 to the concave mirror 7 can be secured longer in a device having the same volume as compared with the conventional case. 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.

  Further, in this embodiment, by adjusting both the angle of the concave mirror 7 and the image display area on the liquid crystal display 5, the visible range 51 is set in the occupant 9 while maintaining the relationship in which the second direction and the third direction are opposite to each other. Although control to change to a position including the position of the first eye is performed (S5, S6), only one of the adjustments may be performed. For example, only the angle of the concave mirror 7 may be adjusted, or only the video display area in the liquid crystal display 5 may be adjusted. Further, the adjustment target may be determined based on the separation distance (that is, the correction amount) between the visible range set in S1 and the eye position of the occupant 9. For example, when the separation distance is less than the threshold value, the visible range 51 is maintained while maintaining the relationship in which the second direction and the third direction are opposite by adjusting only the video display area of the liquid crystal display 5. It changes to the position including the position of the occupant 9's eyes. On the other hand, when the separation distance is equal to or greater than the threshold value, the relationship between the second direction and the third direction is maintained by adjusting the angle of the concave mirror 7 in addition to the image display area of the liquid crystal display 5. The visible range 51 is changed to a position including the position of the occupant 9's eyes.

  In this embodiment, the virtual image generation processing program (see FIG. 7) is executed at the start of virtual image display to adjust the angle of the concave mirror 7 and the video display area of the liquid crystal display 5, but the display of the virtual image is started. After that, the virtual image generation processing program (see FIG. 7) may be executed. In that case, for example, even when the posture of the occupant 9 during driving is changed and the position of the eyes is displaced, it is possible to prevent the quality of the virtual image 10 from being deteriorated.

  Further, in the present embodiment, the CPU 31 of the HUD 1 is configured to execute each step of the virtual image generation processing program (see FIG. 7). However, an in-vehicle device other than the HUD 1 (for example, the navigation device 48), an ECU that controls the vehicle, or the like. It is good also as a structure which performs a one 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 by outputting light having a first polarization direction, and 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. A concave mirror (7) to be visually recognized by the user, and disposed between the video display surface and the concave mirror along an optical path connecting the video display surface and the concave mirror, and reflects light having the first polarization direction. And a reflective polarizing plate (6) that transmits light having a second polarization direction different from the first polarization direction, and the reflective polarizing plate along an optical path connecting the image display surface and the concave mirror. And a concave direction mirror (15) for displacing the polarization direction of light from the first polarization direction to the second polarization direction, and for displaying an image on the image display surface. Video display area to be displayed Display area setting means (31) for setting (52) and angle adjustment means (31) for adjusting the angle of the concave mirror, and the reflective polarizing plate extends in the first direction from the video display surface. The incident optical path is changed to the second direction toward the concave mirror, and the concave mirror transmits the optical path incident in the second direction from the reflective polarizing plate through the reflective polarizing plate to the position of the user's eyes The display area setting means and the angle adjusting means set the image display area so that the second direction and the third direction are opposite to each other, and the display area setting means and the angle adjustment means Adjust the angle.
According to the virtual image display device having the above configuration, after the reflective polarizing plate is disposed between the image display surface and the concave mirror along the optical path, the optical path is once reflected by the reflective polarizing plate and directed to the concave mirror. Since the optical path reflected from the concave mirror is transmitted to the user through the reflective polarizing plate, the optical path length from the image display surface to the concave mirror can be ensured longer in the apparatus of the same volume compared to the conventional one. It becomes possible. As a result, it is possible to reduce the size of the apparatus. In addition, since the direction of the optical path incident on the concave mirror from the reflective polarizing plate and the direction of the optical path reflected by the concave mirror toward the user's eyes are reversed, the quality of the virtual image can be improved. . For example, it becomes possible to make the user visually recognize a clearer and clearer virtual image. Furthermore, by adjusting the image display area with respect to the image display surface and the angle of the concave mirror, the relationship between the members in the reverse direction can be obtained regardless of the position of the user's eyes. This makes it possible to hold the image and prevent the quality of the virtual image from deteriorating.

The second configuration is as follows.
It has eye position acquisition means (31) for acquiring the current user's (9) eye position, and the display area setting means (31) and the angle adjustment means (31) are acquired by the eye position acquisition means. The video display area (52) is set based on the position of the user's eyes, and the angle of the concave mirror (7) is adjusted.
According to the virtual image display device having the above-described configuration, the relationship between the area for displaying the image on the image display surface and the angle of the concave mirror can be adjusted to an appropriate relationship in accordance with the current user eye position. It becomes possible. Therefore, it is possible to prevent the quality of the virtual image from being deteriorated regardless of the position of the user's eyes.

The third configuration is as follows.
A viewable range (51), which is a range of positions of the eyes of the user who can view the video displayed on the video display surface (5), is acquired, and the display area setting means (31) and the angle adjusting means (31) adjusts the angles of the video display area and the concave mirror corresponding to the position of the user's eyes when the position of the user's eyes is out of the visible range.
According to the virtual image display device having the above configuration, even when the user's eye position is out of the visible range, the visible range can be changed to a range including the current user's eye position. Become. It is also possible to maintain a relationship in which the second direction and the third direction are opposite directions.

The fourth configuration is as follows.
The display area setting unit (31) and the angle adjusting unit (31) are configured to determine the angle of the concave mirror (7) when the distance of the user's eye position from the viewable range (51) is less than a threshold value. Is adjusted without adjusting the setting of the video display area (52) corresponding to the position of the user's eyes, and when the distance of the user's eye position from the viewable range is equal to or greater than a threshold value When the displacement of the user's eye position is greater than or equal to the threshold value, the angles of the video display area and the concave mirror are adjusted in accordance with the user's eye position.
According to the virtual image display device having the above configuration, it is possible to change the viewable range to a range including the current user's eye position while reducing the control burden. It is also possible to maintain a relationship in which the second direction and the third direction are opposite directions.

The fifth configuration is as follows.
The angle adjusting means (31) is configured to provide an optical path from the user's eye position to the concave mirror (7) based on the position of the user's eye acquired by the eye position acquiring means (31) and the optical path by the concave mirror. The angle of the concave mirror is adjusted to an angle in which the reflected light path is in the opposite direction, and the display area setting means (31) has the second direction and the third direction when the concave mirror is present at the adjusted angle. The video display area (52) is set in an area where the direction is opposite.
According to the virtual image display apparatus having the above-described configuration, the direction of the optical path incident on the concave mirror from the reflective polarizing plate and the optical path reflected by the concave mirror toward the user's eye position according to the current user eye position. Since a relationship in which the direction is opposite to the direction can be established, the quality of the virtual image can be improved regardless of the position of the user's eyes.

DESCRIPTION OF SYMBOLS 1 Head up display apparatus 2 Vehicle 3 Dashboard 5 Liquid crystal display 6 Reflective polarizing plate 7 Concave mirror 8 Front window 9 Crew 10 Virtual image 15 λ / 4 wavelength plate 18 Optical path 19 Concave mirror angle adjustment motor 31 CPU
32 RAM
33 ROM
34 Flash memory 51 Visible range 52 Video display area

Claims (5)

An image display surface for displaying an image by outputting light having a first polarization direction;
A concave mirror that causes the user to visually recognize 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;
It is disposed between the image display surface and the concave mirror along an optical path connecting the image display surface and the concave mirror, reflects light having the first polarization direction, and is different from the first polarization direction. A reflective polarizing plate that transmits light having the second polarization direction;
It is disposed between the reflective polarizing plate and the concave mirror along an optical path connecting the image display surface and the concave mirror, and the polarization direction of light is displaced from the first polarization direction to the second polarization direction. A polarization direction displacement member to be
Display area setting means for setting a video display area for displaying video on the video display surface;
Angle adjusting means for adjusting the angle of the concave mirror,
The reflective polarizing plate changes an optical path incident in the first direction from the image display surface to a second direction toward the concave mirror,
The concave mirror changes an optical path incident in the second direction from the reflective polarizing plate to a third direction that passes through the reflective polarizing plate and travels toward the user's eyes,
The display area setting unit and the angle adjustment unit are a virtual image display device that sets the video display area and adjusts the angle of the concave mirror so that the second direction and the third direction are opposite to each other. Eye position acquisition means for acquiring the current user's eye position;
2. The virtual image according to claim 1, wherein the display area setting unit and the angle adjustment unit set the video display area based on a user's eye position acquired by the eye position acquisition unit and adjust an angle of the concave mirror. Display device. Obtaining a viewable range that is a range of positions of the eyes of the user that can visually recognize the video displayed on the video display surface;
The display area setting means and the angle adjustment means adjust the angles of the video display area and the concave mirror corresponding to the position of the user's eyes when the position of the user's eyes is out of the visible range. The virtual image display device according to claim 2, wherein the visible range is changed to a range including a position of a user's eyes. The display area setting means and the angle adjustment means are
When the distance of the user's eye position from the visible range is less than the threshold, the setting of the video display area is adjusted according to the user's eye position without adjusting the angle of the concave mirror. Done
When the separation distance of the user's eye position from the viewable range is equal to or greater than the threshold value, and when the displacement of the user's eye position is equal to or greater than the threshold value, the video display is performed corresponding to the user's eye position. The virtual image display device according to claim 3, wherein the angle of the region and the concave mirror is adjusted. The angle adjusting means is configured such that, based on the position of the user's eyes acquired by the eye position acquiring means, the optical path from the position of the user's eyes to the concave mirror and the optical path where the optical path is reflected by the concave mirror are reversed. Adjusting the angle of the concave mirror to an angle of
5. The display area setting unit sets the video display area in an area in which the second direction and the third direction are opposite to each other when the concave mirror is at an adjusted angle. The virtual image display device according to any one of the above.

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