Image generation device, image projection device including said image generation device, and image projection device

Abstract

An image generation device (30) for generating a prescribed image is equipped with an image generation unit (31) for emitting light for generating a prescribed image, a first mirror (32) for reflecting the light, and a bracket (33) for attaching the image generation unit (31). The first mirror (32) is held by the bracket (33).

Description

[Technical Field]

[0001] The present invention relates to an image generation device, an image projection device including the image generation device, and an image projection device. [Background technology]

[0002] In the future, it is expected that vehicles operating in automated driving mode and vehicles operating in manual driving mode will coexist on public roads.

[0003] In the future autonomous driving society, visual communication between vehicles and humans is expected to become increasingly important. For example, visual communication between a vehicle and its occupants is expected to become increasingly important. In this regard, visual communication between a vehicle and its occupants can be realized using a head-up display (HUD). A head-up display projects images or videos onto a windshield or combiner, and the images are superimposed on the real world through the windshield or combiner for the occupants to view, thereby realizing so-called augmented reality (AR).

[0004] Patent Document 1 discloses a head-up display device including a display light emitting device that emits display light, a plane mirror that reflects the display light from the display light emitting device, and a reflecting mirror that reflects the display light reflected by the plane mirror and guides it to a windshield or a combiner. This head-up display device has a housing that houses the display light emitting device, the plane mirror, the concave mirror, etc.

[0005] Furthermore, Patent Document 2 discloses a head-up display in which light for forming an image emitted from an image generating unit is reflected by a concave mirror and projected onto the windshield of a vehicle. Part of the light projected onto the windshield is reflected by the windshield and directed toward the driver's eyes. The driver perceives the reflected light as a virtual image that looks like an image of an object on the other side of the windshield (outside the vehicle), with real objects visible through the windshield as the background.

[0006] The concave mirror is rotatable. The concave mirror is rotated in accordance with the driver's viewpoint so that the virtual image is displayed at a position corresponding to the driver's viewpoint. This changes the position of the light projected onto the windshield.

[0007] Patent Document 3 discloses a head-up display in which light for forming an image emitted from an image generating device is reflected by a concave mirror and projected onto a vehicle windshield. The image generating device includes a light source, a lens that transmits the light emitted from the light source, and a display device that forms light for generating an image using the light that has transmitted through the lens.

[0008] Furthermore, Patent Document 4 discloses a head-up display in which light for forming an image emitted from an image generating unit is reflected by a concave mirror and projected onto the windshield of a vehicle. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2020-117106 [Patent Document 2] Japanese Patent Application Publication No. 2018-205509 [Patent Document 3] Japanese Patent Application Publication No. 2020-170067 [Patent Document 4] International Publication No. 2020 / 110580 Summary of the Invention [Problem to be solved by the invention]

[0010] In a conventional head-up display such as that disclosed in Patent Document 1, the projector device and the plane mirror are individually fixed to the housing, which can result in a decrease in the positional accuracy between the projector device (image generating device) and the plane mirror.

[0011] Therefore, an object of the present invention is to provide an image generating device that improves the positional accuracy between the image generating unit and the first mirror and enables the first mirror to be made smaller, and an image projection device that is equipped with such an image generating device.

[0012] Furthermore, when the concave mirror is rotated in accordance with the driver's viewpoint, the optical path length between the light reflection position on the concave mirror and the light incidence position on the windshield changes, and therefore the quality of the virtual image changes.

[0013] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image projection device that can change the display position of an image in accordance with the viewpoint position of an occupant and that reduces changes in image quality.

[0014] Furthermore, in a head-up display such as that disclosed in Patent Document 3, the display device may be disposed at an angle relative to a direction perpendicular to the optical axis of the light source due to the shape and arrangement of other components such as the concave mirror. In this case, the area of ​​the display device closer to the lens's light exit surface is brightly illuminated, while the area of ​​the display device farther from the lens's light exit surface is darkly illuminated. As a result, there is a risk of uneven light distribution occurring in the light emitted from the lens and irradiated onto the display device.

[0015] Therefore, an object of the present invention is to provide an image generating device and an image projection device that suppress uneven light distribution of light projected onto a display device that is tilted with respect to a direction perpendicular to the optical axis of the light source.

[0016] Furthermore, in a head-up display such as that disclosed in Patent Document 4, a heat sink, for example, is provided to dissipate heat generated when the light source of the image generating unit emits light, but there is room for improvement in the heat dissipation structure.

[0017] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image projection device with good heat dissipation efficiency. [Means for solving the problem]

[0018] In order to achieve one of the above objects, an image generating apparatus according to one aspect of the present invention comprises: 1. An image generating device for generating a predetermined image, comprising: an image generating unit that emits light for generating the predetermined image; a first mirror that reflects the light; a bracket for mounting the image generating unit; Equipped with The first mirror is held by the bracket.

[0019] Furthermore, an image projection device according to one aspect of the present invention comprises: The image generating device described above; and a second mirror that reflects the light emitted by the image generating unit and reflected by the first mirror so that the light is irradiated onto a transparent member.

[0020] In order to achieve one of the above objects, an image projection device according to one aspect of the present invention comprises: An image projection device for a vehicle configured to display a predetermined image, an image generating unit that emits light for generating the predetermined image; a reflecting unit that is rotatably provided and has a reflecting surface that reflects the light emitted by the image generating unit, the reflecting surface has a curved surface with a different radius of curvature, The reflecting portion rotates so that the light incident on the reflecting portion is irradiated onto the curved surfaces having different radii of curvature.

[0021] When the reflecting unit is rotated, the reflection direction of the light reflected by the reflecting surface changes. This changes the optical path length between the reflection position of the light on the reflecting surface and the incident position of the light on the member onto which the reflected light is projected, causing distortion of the predetermined image. With the above configuration, the light incident on the reflecting surface is reflected by a curved surface with a different radius of curvature depending on the rotation of the reflecting unit, thereby reducing distortion of the predetermined image caused by changes in the optical path length. Therefore, the display position of the image can be changed according to the viewpoint position of the occupant, and changes in image quality are reduced.

[0022] In order to achieve one of the above objects, an image generating apparatus according to one aspect of the present invention comprises: A light source and a lens that transmits light emitted from the light source; a display device that forms light for generating an image using light transmitted through the lens; It is equipped with the display device is tilted with respect to a direction perpendicular to the optical axis of the light source; The light source is disposed at a position corresponding to the inclination, being shifted from a predetermined position.

[0023] In order to achieve one of the above objects, an image projection device according to one aspect of the present invention comprises: An image projection device for a vehicle configured to display a predetermined image, the image generation device; at least one reflecting portion that reflects the light emitted by the image generating device; It is equipped with:

[0024] With the above configuration, a portion of the light emitted from the light source and transmitted through the lens is emitted toward an area of ​​the display device that is far from the exit surface of the lens, thereby suppressing uneven light distribution of the light irradiated onto the display device that is tilted relative to the direction perpendicular to the optical axis of the light source.

[0025] In order to achieve one of the above objects, an image projection device according to one aspect of the present invention comprises: An image projection device for a vehicle configured to display a predetermined image, an image generating unit that includes a light source and emits light for generating the predetermined image using light from the light source; a concave mirror that reflects the light emitted by the image generation unit; It is equipped with When the image projection device is attached to the body of the vehicle, the optical axis of the light source is inclined downward toward the concave mirror.

[0026] With the above-described configuration, heat generated by the light source is transferred into the air and rises with the air. Because the optical axis of the light source is tilted downward toward the concave mirror, the heat transferred into the air rises with the air without being blocked by the components of the image generation unit. This makes it possible to provide an image projection device with good heat dissipation efficiency. [Effects of the Invention]

[0027] According to the present invention, it is possible to provide an image generation device that improves the positional accuracy between the image generation unit and the first mirror and enables the first mirror to be made smaller, and a head-up display that includes the image generation device.

[0028] Furthermore, according to the present invention, it is possible to provide an image projection device that can change the display position of an image in accordance with the viewpoint position of the occupant and that reduces changes in image quality.

[0029] Furthermore, according to the present invention, it is possible to suppress unevenness in the light distribution of light irradiated onto a display device that is tilted with respect to a direction perpendicular to the optical axis of the light source.

[0030] Furthermore, according to the present invention, it is possible to provide an image projection device with good heat dissipation efficiency. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a block diagram of a vehicle system including an image generation device and a head-up display (HUD) according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram illustrating the configuration of the HUD shown in FIG. [Figure 3] FIG. 2 is a perspective view showing an image generating device and a concave mirror of the HUD shown in FIG. [Figure 4] FIG. 2 is a perspective view showing the configuration of the image generating device shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing the mounting state of the plane mirror shown in FIG. [Figure 6] FIG. 10 is a schematic diagram showing the configuration of a head-up display (HUD) according to a second embodiment. [Figure 7] 10A and 10B are diagrams for explaining the optical paths of light for forming virtual image objects that are displayed at different positions corresponding to the viewpoint positions of occupants. [Figure 8] 7 is a diagram showing an area on the reflecting surface of the concave mirror shown in FIG. 6 that is irradiated by light incident on the concave mirror. [Figure 9] 10A and 10B are diagrams showing virtual image objects visually recognized by an occupant when the occupant's viewpoint is at a reference position. [Figure 10] 10A and 10B are diagrams illustrating virtual image objects visually recognized by an occupant when the occupant's viewpoint is at a position higher than a reference position. [Figure 11] 10A and 10B are diagrams illustrating virtual image objects visually recognized by an occupant when the occupant's viewpoint is at a position lower than the reference position. [Figure 12] 10A and 10B are diagrams for explaining the optical paths of light for forming virtual image objects that are displayed at different positions corresponding to the viewpoint positions of occupants. [Figure 13] 10A and 10B are diagrams for explaining the optical paths of light for forming virtual image objects that are displayed at different positions corresponding to the viewpoint positions of occupants. [Figure 14] 7 is a diagram showing an area on the reflecting surface of the concave mirror shown in FIG. 6 that is irradiated by light incident on the concave mirror. [Figure 15] 10A and 10B are diagrams showing virtual image objects visually recognized by an occupant when the occupant's viewpoint is at a reference position. [Figure 16] 10A and 10B are diagrams illustrating virtual image objects visually recognized by an occupant when the occupant's viewpoint is at a position higher than a reference position. [Figure 17] 10A and 10B are diagrams illustrating virtual image objects visually recognized by an occupant when the occupant's viewpoint is at a position lower than the reference position. [Figure 18] FIG. 10 is a schematic diagram showing the configuration of a head-up display (HUD) according to a third embodiment. [Figure 19] FIG. 19 is a cross-sectional view showing the configuration of the image generating device shown in FIG. [Figure 20] FIG. 1 is a cross-sectional view showing a configuration of an image generating device according to a reference embodiment. [Figure 21] 20 is a cross-sectional view showing a schematic optical path of light emitted from a light source in the image generating device shown in FIG. 19. [Figure 22] FIG. 10 is a schematic diagram showing the configuration of a head-up display (HUD) according to a fourth embodiment. [Figure 23] 23 is a schematic diagram for explaining the configuration of an image generating unit of the HUD shown in FIG. 22. FIG. [Figure 24] FIG. 10 is a schematic diagram showing another example of the configuration of the image generating unit. [Figure 25] FIG. 10 is a schematic diagram showing another example of the configuration of the image generating unit. [Figure 26] FIG. 26 is a perspective view for explaining the configuration of the heat sink in FIG. 25. [Figure 27] FIG. 10 is a schematic diagram showing another example of the configuration of the HUD. DETAILED DESCRIPTION OF THE INVENTION

[0032] [First embodiment] A first embodiment of the present invention (hereinafter referred to as the present embodiment) will be described with reference to the drawings. In this embodiment, for convenience of explanation, the terms "left-right direction," "up-down direction," and "front-rear direction" may be referred to as appropriate. These directions are relative directions set for the HUD (Head-Up Display) 20 shown in FIG. 2. Here, the "left-right direction" refers to a direction including the "left direction" and the "right direction." The "up-down direction" refers to a direction including the "upward direction" and the "downward direction." The "front-rear direction" refers to a direction including the "forward direction" and the "rearward direction." Although not shown in FIG. 2, the left-right direction refers to a direction perpendicular to the up-down direction and the front-rear direction.

[0033] A vehicle system 2 including a HUD 20 according to this embodiment will be described with reference to Fig. 1. A vehicle 1 equipped with the vehicle system 2 may be, for example, a vehicle (automobile) capable of running in an autonomous driving mode.

[0034] 1, the vehicle system 2 includes a vehicle control unit 3, a sensor 5, a camera 6, a radar 7, an HMI (Human Machine Interface) 8, a GPS (Global Positioning System) 9, a wireless communication unit 10, and a storage device 11. The vehicle system 2 also includes a steering actuator 12, a steering device 13, a brake actuator 14, a brake device 15, an accelerator actuator 16, and an accelerator device 17. The vehicle system 2 also includes a HUD 20.

[0035] The vehicle control unit 3 is configured to control the running of the vehicle 1. The vehicle control unit 3 is configured, for example, by at least one electronic control unit (ECU).

[0036] The sensor 5 includes at least one of an acceleration sensor, a speed sensor, and a gyro sensor. The sensor 5 is configured to detect the driving state of the vehicle 1 and output driving state information to the vehicle control unit 3. The sensor 5 may further include a seating sensor that detects whether the driver is sitting in the driver's seat, a face direction sensor that detects the direction of the driver's face, an external weather sensor that detects the external weather conditions, and a human presence sensor that detects whether a person is inside the vehicle.

[0037] The camera 6 includes one or more external cameras 6A and an internal camera 6B. The external camera 6A is configured to acquire image data showing the surrounding environment of the vehicle 1 and transmit the image data to the vehicle control unit 3. The internal camera 6B is disposed inside the vehicle 1 and configured to acquire image data showing the occupant. The internal camera 6B functions, for example, as an eye-tracking camera that tracks the occupant's viewpoint E (described later in FIG. 2). The internal camera 6B is provided, for example, near the rearview mirror or inside the instrument panel.

[0038] The radar 7 includes at least one of a millimeter wave radar, a microwave radar, and a laser radar (e.g., a LiDAR unit). For example, the LiDAR unit is configured to acquire 3D mapping data (point cloud data) indicating the surrounding environment of the vehicle 1, and then transmit the 3D mapping data to the vehicle control unit 3.

[0039] The HMI 8 is composed of an input unit that accepts input operations from the driver and an output unit that outputs driving information and the like to the driver. The input unit includes a steering wheel, an accelerator pedal, a brake pedal, a driving mode changeover switch that changes the driving mode of the vehicle 1, and the like. The output unit is a display (excluding the HUD) that displays various driving information.

[0040] The GPS 9 is configured to acquire current position information of the vehicle 1 and output the acquired current position information to the vehicle control unit 3.

[0041] The wireless communication unit 10 is configured to receive information about other vehicles around the vehicle 1 from the other vehicles and transmit information about the vehicle 1 to the other vehicles (vehicle-to-vehicle communication).The wireless communication unit 10 is also configured to receive infrastructure information from infrastructure facilities such as traffic lights and marker lights and transmit driving information about the vehicle 1 to the infrastructure facilities (road-to-vehicle communication).The wireless communication unit 10 is also configured to receive information about pedestrians from portable electronic devices carried by pedestrians and transmit driving information about the vehicle 1 to the portable electronic device (pedestrian-to-vehicle communication).

[0042] The storage device 11 is an external storage device such as a hard disk drive (HDD) or a solid state drive (SSD), etc. The storage device 11 is configured to output map information and a vehicle control program to the vehicle control device 3 in response to a request from the vehicle control device 3.

[0043] When the vehicle 1 is traveling in an autonomous driving mode, the steering actuator 12 is configured to receive a steering control signal from the vehicle control unit 3 and control the steering device 13. The brake actuator 14 is configured to receive a brake control signal from the vehicle control unit 3 and control the brake device 15. The accelerator actuator 16 is configured to receive an accelerator control signal from the vehicle control unit 3 and control the accelerator device 17.

[0044] The vehicle control unit 3 automatically controls the driving of the vehicle 1 based on driving state information, surrounding environment information, current position information, map information, etc. The driving modes include an automatic driving mode and a manual driving mode. In the automatic driving mode, the driving of the vehicle 1 is automatically controlled by the vehicle system 2. On the other hand, in the manual driving mode, the steering control signal, accelerator control signal, and brake control signal are generated by manual operation by the driver, so that the driving of the vehicle 1 is controlled by the driver. The automatic driving modes include, for example, a fully automatic driving mode, an advanced driving assistance mode, and a driving assistance mode.

[0045] The HUD 20 is configured to display predetermined information (hereinafter referred to as HUD information) as an image to the occupants of the vehicle 1 so that the HUD information is superimposed on the real space outside the vehicle 1 (particularly, the surrounding environment ahead of the vehicle 1). The HUD information displayed by the HUD 20 is, for example, vehicle driving information related to the driving of the vehicle 1 and / or surrounding environment information related to the surrounding environment of the vehicle 1 (particularly, information related to objects present outside the vehicle 1). The HUD 20 is an AR display that functions as a visual interface between the vehicle 1 and the occupants.

[0046] The HUD 20 includes a picture generation unit (PGU) 30 and a control unit 25. The image generating device 30 is configured to emit light for generating a predetermined image to be displayed toward the occupants of the vehicle 1. The image generating device 30 can emit light for generating a changing image that changes depending on the situation of the vehicle 1, for example.

[0047] The control unit 25 controls the operation of each unit of the HUD 20. The control unit 25 is connected to the vehicle control unit 3 and generates a control signal for controlling the operation of the image generation device 30 based on, for example, vehicle driving information and surrounding environment information transmitted from the vehicle control unit 3, and transmits the generated control signal to the image generation device 30. The control unit 25 is equipped with a processor such as a CPU (Central Processing Unit) and a memory, and the processor executes a computer program read from the memory to control the operation of the image generation device 30 and the like. Note that, in this embodiment, the vehicle control unit 3 and the control unit 25 are provided as separate components, but the vehicle control unit 3 and the control unit 25 may also be configured as an integrated unit. For example, the vehicle control unit 3 and the control unit 25 may be configured as a single electronic control unit.

[0048] Next, a specific configuration of the HUD 20 according to this embodiment will be described with reference to Figs. 2 to 5. Fig. 2 is a schematic diagram of the HUD 20 mounted on the vehicle 1, viewed from the side of the vehicle 1. Fig. 3 is a diagram showing the image generation device 30 and the concave mirror 40. Fig. 4 is a perspective view showing the configuration of the image generation device 30.

[0049] 2, at least a portion of the HUD 20 is located inside the vehicle 1. Specifically, the HUD 20 is installed at a predetermined location inside the vehicle 1. For example, the HUD 20 may be disposed inside the dashboard of the vehicle 1.

[0050] The HUD 20 includes a HUD main body 21. The HUD main body 21 includes a housing 22 and an exit window 23. The exit window 23 is made of a transparent plate that transmits visible light. The HUD main body 21 includes an image generating device 30 and a concave mirror 40 (an example of a second mirror) inside the housing 22. In this embodiment, the control unit 25 of the HUD 20 is housed in the image generating device 30.

[0051] As shown in FIGS. 2 and 3, the concave mirror 40 is provided in front of the image generating device 30 inside the housing 22. The concave mirror 40 is arranged on the optical path of the light emitted from the image generating device 30. The concave mirror 40 is configured to reflect the light emitted from the image generating device 30 toward the transparent member 18 (for example, the front window of the vehicle 1). The concave mirror 40 has a reflective surface that is curved concavely to form a predetermined image, and reflects the image of the light emitted from the image generating device 30 and focused thereon at a predetermined magnification. A reflective film is formed on the reflective surface of the concave mirror 40 (the surface facing the image generating device 30) by vapor-depositing a metal such as aluminum.

[0052] The concave mirror 40 has support shafts 41 on both the left and right sides. The concave mirror 40 is supported by the housing 22 via the support shafts 41. The concave mirror 40 is rotatable about the support shafts 41, and is configured so that its orientation relative to the image generating device 30 can be changed by rotating. The concave mirror 40 has, for example, a drive mechanism 42. The drive mechanism 42 is configured so that the position and orientation of the concave mirror 40 can be changed based on a control signal sent from the control unit 25.

[0053] The image generating device 30 is disposed within the housing 22 so as to face the concave mirror 40. Light emitted from the image generating device 30 is reflected by the concave mirror 40 and emitted from the exit window 23 of the HUD main body 21. The light emitted from the exit window 23 of the HUD main body 21 is irradiated onto the transparent member 18. A portion of the light irradiated from the exit window 23 onto the transparent member 18 is reflected toward the occupant's viewpoint E. As a result, the occupant perceives the light emitted from the image generating device 30 as a virtual image (predetermined image) formed at a predetermined distance in front of the transparent member 18. In this way, the image displayed by the HUD 20 is superimposed on the real space in front of the vehicle 1 through the transparent member 18, and as a result, the occupant can visually perceive a virtual image object I formed by the predetermined image as floating above the road outside the vehicle.

[0054] Here, the occupant's viewpoint E may be either the viewpoint of the left eye or the viewpoint of the right eye of the occupant. Alternatively, the viewpoint E may be defined as the midpoint of a line segment connecting the viewpoint of the left eye and the viewpoint of the right eye. The position of the occupant's viewpoint E is identified based on image data acquired by the internal camera 6B, for example. The position of the occupant's viewpoint E may be updated at a predetermined interval or may be determined only once when the vehicle 1 is started.

[0055] When a 2D image (planar image) is formed as the virtual image object I, a predetermined image is projected so as to become a virtual image at a single distance that is arbitrarily determined. When a 3D image (stereoscopic image) is formed as the virtual image object I, a plurality of predetermined images that may be identical or different from one another are projected so as to become virtual images at different distances. The distance of the virtual image object I (the distance from the occupant's viewpoint E to the virtual image) can be adjusted as appropriate by adjusting the distance from the image generation device 30 to the occupant's viewpoint E (for example, by adjusting the distance between the image generation device 30 and the concave mirror 40).

[0056] As shown in FIGS. 3 and 4, an image generating device 30 according to this embodiment includes an image generating section 31, a plane mirror 32 (an example of a first mirror), a bracket 33, and a heat sink .

[0057] The image generating unit 31 emits light for generating a predetermined image. The image generating unit 31 is mounted on a bracket 33.

[0058] The plane mirror 32 is a component for reflecting the light emitted from the image generating unit 31 toward the concave mirror 40. The plane mirror 32 is provided between the image generating unit 31 and the concave mirror 40 on the optical path of the light emitted from the image generating unit 31. The plane mirror 32 is held by a bracket 33 on which the image generating unit 31 is mounted. The plane mirror 32 is positioned at a certain angle with respect to the light emission surface of the image generating unit 31 so as to reflect the light emitted from the image generating unit 31 toward the concave mirror 40. A reflective film is formed on the reflective surface of the plane mirror 32 (the lower surface facing the image generating unit 31) by vapor deposition of a metal such as aluminum. Note that instead of forming a reflective film on the plane mirror 32 by vapor deposition of aluminum, the plane mirror 32 itself may be made of a white resin material capable of reflecting light.

[0059] The bracket 33 is a member for attaching the image generation unit 31 to the housing unit 22. The bracket 33 is made of, for example, a resin material. The bracket 33 includes a base 34 and a pair of protrusions 35A and 35B protruding from the base 34.

[0060] The base 34 is made of a rectangular flat plate member. An opening 34a is provided in the center of the base 34, and the image generation unit 31 is attached in a state where it is inserted through the opening 34a. Furthermore, screw holes 34b are provided on both left and right ends of the base 34 for fixing the bracket 33 to the housing 22. The bracket 33 is fixed to the housing 22 so that the top surface of the base 34 is parallel to a fixing surface of the housing 22 (for example, the bottom surface of the housing 22).

[0061] Each of the pair of protrusions 35A, 35B is formed of a rectangular flat plate member. The pair of protrusions 35A, 35B is arranged to sandwich the image generation unit 31, which is fixed to the center of the base 34, from the left and right. Each of the protrusions 35A, 35B protrudes from the base 34 in the emission direction of light emitted from the image generation unit 31, i.e., toward the upper side of the HUD 20. Each of the protrusions 35A, 35B is formed with an inclination such that its tip is lower on the rear side than on the front side. A plane mirror 32 is attached to the tip of each of the protrusions 35A, 35B along the inclination of the tip. The plane mirror 32 is attached so as to cover the upper side between the protrusions 35A and 35B. The front and rear sides between the protrusions 35A and 35B are open. The side surfaces of the protrusions 35A and 35B facing the image generating unit 31 are preferably painted, for example, black so as not to reflect the light emitted from the image generating unit 31.

[0062] 5 is a cross-sectional view of the image generating device 30 showing the state in which the plane mirror 32 is attached to the bracket 33. As shown in Fig. 5, the image generating unit 31 includes a light source 101 mounted on a substrate 102, a lens 103 arranged above the light source 101, and a display device 104 arranged above the lens 103. A heat sink 36 is attached to the underside of the substrate 102.

[0063] The lens 103 is configured to transmit or reflect the light emitted from the light source 101 and emit the light toward the display device 104. The display device 104 is, for example, a liquid crystal display, a DMD (Digital Mirror Device), etc. The upper surface of the display device 104 forms a light emission surface of the image generation unit 31 that emits the light from the light source 101 that has passed through the lens 103 toward the plane mirror 32.

[0064] 4, the tip of each of the protrusions 35A, 35B is inclined at a certain angle θ1 with respect to the mounting surface of the base 34. A plane mirror 32 is attached along the inclination of the tip of each of the protrusions 35A, 35B. In other words, the plane mirror 32 is attached to the tip of each of the protrusions 35A, 35B so as to form an angle θ1 with respect to the mounting surface of the base 34 on which the image generation unit 31 is mounted.

[0065] Furthermore, the display device 104, which is the light emission surface of the image generation unit 31, is attached at an angle θ3 with respect to the mounting surface of the base 34 on which the image generation unit 31 is mounted. This prevents reflected light of the light emitted from the light source 101 from directly entering the light source 101. The angle θ3 may be any angle that can suppress reflected light from directly entering the light source 101.

[0066] The angle θ1 formed between the plane mirror 32 and the mounting surface of the base 34 is configured to be larger than the angle θ3 formed between the display device 104, which is the light emission surface of the image generation unit 31, and the mounting surface of the base 34. In other words, the plane mirror 32 is attached so as to form a predetermined angle θ2 with respect to the display device 104, where θ2 + θ3 = θ1. In this way, by attaching the plane mirror 32 to the protrusions 35A and 35B of the bracket 33 so as to form a constant angle θ1, the light emitted from the light source 101 is reflected by the plane mirror 32, and further reflected by the concave mirror 40, and then irradiated onto the transparent member 18.

[0067] Also, as shown in FIG. 5, the distance from the display device 104 to the plane mirror 32 is configured to be shorter than the distance from the plane mirror 32 to the concave mirror 40. That is, if the distance from the display device 104, which is the light-emitting surface of the image generation unit 31, to the reflecting surface of the plane mirror 32 is L1, and the distance from the reflecting surface of the plane mirror 32 to the reflecting surface of the concave mirror 40 is L2, the mounting positions of the respective members are set such that L1 < L2.

[0068] As described above, the image generation device 30 of the present embodiment includes an image generation unit 31 that emits light for generating a predetermined image, a plane mirror 32 (an example of a first mirror) that reflects the light emitted from the image generation unit 31, and a bracket 33 for mounting the image generation unit 31, and the plane mirror 32 is held by the bracket 33. According to this configuration, since the plane mirror 32 is held by the bracket 33, the image generation unit 31 and the plane mirror 32 are integrated. Therefore, variations in the mounting position of the plane mirror 32 with respect to the image generation unit 31 can be suppressed, and the positional accuracy of the plane mirror 32 with respect to the image generation unit 31 can be increased. Further, although the plane mirror 32 is a relatively expensive member that is subjected to an aluminum vapor deposition process or the like, according to the present embodiment, since the positional accuracy of the plane mirror 32 with respect to the image generation unit 31 is increased, the plane mirror 32 can be miniaturized, and component costs can be reduced.

[0069] Also, according to the image generation device 30, the bracket 33 has a base body 34 on which the image generation unit 31 is mounted, and a pair of protruding portions 35A and 35B that are arranged so as to sandwich the image generation unit 31 and protrude from the base body 34 in the light emission direction from the image generation unit 31. Then, the plane mirror 32 is mounted on the pair of protruding portions 35A and 35B. By using the bracket 33 having such a simple configuration, the positional accuracy of the plane mirror 32 with respect to the image generation unit 31 can be improved, and miniaturization of the plane mirror 32 can be achieved.

[0070] Furthermore, according to image generating device 30, each of protrusions 35A, 35B is configured so that its tip is angled at a certain angle θ1 with respect to the mounting surface of base 34 of bracket 33 on which image generating unit 31 is mounted, and plane mirror 32 is attached to the tip. Therefore, plane mirror 32 can be integrated with image generating unit 31 so that the angle formed between display device 104, which is the light emission surface of image generating unit 31, and the reflecting surface of plane mirror 32 becomes a desired angle θ2.

[0071] Furthermore, the head-up display 20 (an example of an image projection device) of this embodiment includes an image generation device 30 and a concave mirror 40 (an example of a second mirror) that reflects light so that the light emitted from the image generation unit 31 and reflected by the plane mirror 32 is irradiated onto the transparent member 18. According to this configuration, by reflecting the light emitted from the image generation unit 31 by a plurality of mirror members, namely the plane mirror 32 and the concave mirror 40, it is possible to lengthen the optical path length from the image generation unit 31 to the transparent member 18 within the housing 22 while maintaining the positional accuracy of the plane mirror 32. This makes it possible to achieve a reduction in the overall size of the head-up display while ensuring the optical path length necessary to generate a virtual image (a predetermined image).

[0072] Furthermore, the head-up display 20 is configured so that the distance L1 between the display device 104, which is the light emission surface of the image generation unit 31, and the reflective surface of the plane mirror 32 is shorter than the distance L2 between the reflective surface of the plane mirror 32 and the reflective surface of the concave mirror 40. By shortening the distance L1 between the image generation unit 31 and the plane mirror 32 in this way, it is possible to suppress the spread of the emitted light when it reaches the plane mirror 32, and also to suppress deviation in the arrival position of the emitted light when it reaches the plane mirror 32. This allows the plane mirror 32 to be further miniaturized.

[0073] In the above embodiment, the bracket 33 of the image generating device 30 is formed from a resin material, but this is not limiting. For example, the bracket 33 may be formed from a metal material with high heat dissipation properties (e.g., aluminum). With this configuration, the bracket 33 itself can function as a heat sink. In this case, for example, the heat sink 36 as in the above embodiment may not be provided. Furthermore, in addition to or instead of the heat sink 36, heat dissipation fins may be provided on the outer surfaces of the protrusions 35A and 35B, for example.

[0074] Furthermore, in the above embodiment, a configuration has been described in which the concave mirror 40 is supported by the housing 22 of the HUD main body 21, but this is not limiting. For example, the concave mirror 40 may be supported by the bracket 33 of the image generating device 30. Furthermore, in a configuration in which the concave mirror 40 is supported by the bracket 33 of the image generating device 30, the light emitted from the image generating unit 31 may be reflected only by the concave mirror 40 and irradiated onto the transparent member 18, without providing the plane mirror 32.

[0075] Furthermore, in the above embodiment, the front window (windshield) of the vehicle 1 is given as an example of the transparent member 18, but this is not limiting. For example, the transparent member 18 may be a combiner (not shown) provided inside the front window. The combiner is made of, for example, a transparent plastic disk. A portion of the light irradiated onto the combiner from the image generating device 30 of the HUD main body 21 is reflected toward the occupant's viewpoint E, similar to when light is irradiated onto the front window.

[0076] Furthermore, the classification and display format of the vehicle's driving modes may be changed as appropriate in accordance with the laws, regulations, or rules related to autonomous driving in each country. Similarly, the definitions of "fully autonomous driving mode," "advanced driving assistance mode," and "driving assistance mode" described in the description of this embodiment are merely examples, and these definitions may be changed as appropriate in accordance with the laws, regulations, or rules related to autonomous driving in each country.

[0077] [Second embodiment] A second embodiment of the present invention will be described below with reference to the drawings. For convenience of explanation, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component. In the drawings, arrow U indicates the upward direction of the illustrated structure. Arrow D indicates the downward direction of the illustrated structure. Arrow F indicates the forward direction of the illustrated structure. Arrow B indicates the rearward direction of the illustrated structure. Arrow L indicates the leftward direction of the illustrated structure. Arrow R indicates the rightward direction of the illustrated structure. These directions are relative directions set for the HUD 20 shown in FIG. 6.

[0078] 6 is a schematic diagram of a HUD 20 according to the second embodiment, viewed from the side of the vehicle 1. The HUD 20 is provided in the vehicle 1. For example, the HUD 20 is disposed in the dashboard of the vehicle 1. The HUD 20 is an example of an image projection device.

[0079] The HUD 20 functions as a visual interface between the vehicle 1 and the occupants of the vehicle 1. Specifically, the HUD 20 is configured to display predetermined information as a predetermined image so that the predetermined information is superimposed on the real space outside the vehicle 1 (particularly, the surrounding environment ahead of the vehicle 1). The image may include a still image or a moving image (video). The information displayed by the HUD 20 may be, for example, vehicle driving information related to the driving of the vehicle 1 and / or surrounding environment information related to the surrounding environment of the vehicle 1 (particularly, information related to objects present outside the vehicle 1).

[0080] As shown in FIG. 6, the HUD 20 includes a HUD main body 21. The HUD main body 21 has a housing 22 and an exit window 23. The exit window 23 is made of a transparent plate that transmits visible light. The HUD main body 21 has an image generation unit (PGU) 24, a control unit 25, a concave mirror 26, and a drive mechanism 28 inside the housing 22. The concave mirror 26 is an example of a reflecting unit.

[0081] The image generation unit 24 is configured to emit light for generating a predetermined image. The image generation unit 24 is fixed to the housing 22. The light emitted from the image generation unit 24 is, for example, visible light. Although detailed illustrations are omitted, the image generation unit 24 includes a light source, optical components, and a display device. The light source is, for example, an LED light source or a laser light source. The LED light source is, for example, a white LED light source. The laser light source is, for example, an RGB laser light source configured to emit red laser light, green laser light, and blue laser light, respectively. The optical components include a prism, a lens, a diffuser, a magnifying glass, etc. as appropriate. The optical components transmit the light emitted from the light source and emit it toward the display device. The display device is, for example, a liquid crystal display, a DMD, etc. The drawing method of the image generation unit 24 may be a raster scan method, a DLP (Digital Light Processing) method, or an LCOS (Liquid Crystal On Silicon) method. When the DLP system or the LCOS system is adopted, the light source of the image generating unit 24 may be an LED light source. When the liquid crystal display system is adopted, the light source of the image generating unit 24 may be a white LED light source.

[0082] The control unit 25 controls the operation of each unit of the HUD 20. The control unit 25 is connected to a vehicle control unit (not shown) of the vehicle 1, and generates a control signal for controlling the operation of the image generation unit 24 based on, for example, vehicle driving information and surrounding environment information transmitted from the vehicle control unit, and transmits the generated control signal to the image generation unit 24. The control unit 25 is equipped with a processor such as a CPU and a memory, and the processor executes a computer program read from the memory to control the operation of the image generation unit 24, etc.

[0083] The concave mirror 26 is disposed on the optical path of the light emitted from the image generation unit 24. Specifically, the concave mirror 26 is disposed in front of the image generation unit 24 within the housing 22. The concave mirror 26 is configured to reflect the light emitted from the image generation unit 24 upward toward the transparent member 18 (for example, the front window of the vehicle 1). The concave mirror 26 reflects the light image emitted from the image generation unit 24 and formed thereon by the reflecting surface 261 at a predetermined magnification. The concave mirror 26 has a reflecting surface 261 that is concavely curved. The reflecting surface 261 has a curved surface with a different radius of curvature. For example, the reflecting surface 261 can be formed to have a different radius of curvature along the vertical direction. The radius of curvature may change continuously or may change stepwise within a predetermined range.

[0084] Driving mechanism 28 is configured to be able to change the position of concave mirror 26 (the orientation of reflecting surface 261) based on a control signal transmitted from control unit 25. Concave mirror 26 is displaced to a predetermined position by being rotated around rotation axis 26A by driving mechanism 28.

[0085] The light emitted from the image generation unit 24 is reflected by the concave mirror 26 and emitted from the exit window 23 of the HUD main body 21. The light emitted from the exit window 23 of the HUD main body 21 is irradiated onto the transparent member 18. A portion of the light irradiated from the exit window 23 onto the transparent member 18 is reflected toward the occupant's viewpoint E. As a result, the occupant recognizes the light emitted from the HUD main body 21 as a virtual image (predetermined image) formed at a predetermined distance in front of the transparent member 18. In this way, the image displayed by the HUD 20 is superimposed on the real space in front of the vehicle 1 through the transparent member 18, and as a result, the occupant can visually recognize the virtual image object I formed by the predetermined image as floating above the road located outside the vehicle.

[0086] When a 2D image (planar image) is formed as the virtual image object I, a predetermined image is projected to become a virtual image at a single distance that is arbitrarily determined. When a 3D image (stereoscopic image) is formed as the virtual image object I, a plurality of predetermined images that are the same or different from one another are projected to become virtual images at different distances. The distance of the virtual image object I (the distance from the occupant's viewpoint E to the virtual image) can be adjusted as appropriate by adjusting the distance from the image generation unit 24 to the occupant's viewpoint E. For example, the distance of the virtual image object I can be adjusted as appropriate by adjusting the optical path length between the image generation unit 24 and the concave mirror 26.

[0087] The display position of the virtual image object I is changed depending on the position of the occupant's viewpoint E. For example, the position of the occupant's viewpoint E can be identified by the control unit 25 based on image data acquired by a camera arranged inside the vehicle 1. The occupant's viewpoint E may be either the viewpoint of the occupant's left eye or the viewpoint of the occupant's right eye. Alternatively, the viewpoint E may be defined as the midpoint of a line segment connecting the viewpoint of the left eye and the viewpoint of the right eye.

[0088] The control unit 25 generates a control signal based on the identified position of the occupant's viewpoint E. The drive mechanism 28 rotates the concave mirror 26 based on the control signal. As the position of the concave mirror 26 (the orientation of the reflecting surface 261) changes, the incident position of the light projected onto the transparent member 18 changes. As a result, the virtual image object I is displayed at a position corresponding to the position of the occupant's viewpoint E. Note that the position of the occupant's viewpoint E may be identified based on an input operation from the occupant.

[0089] Fig. 7 is a reference example showing the optical paths of light reflected from the concave mirror 126 when the display positions of the virtual image objects I1 to I3 are changed in accordance with the viewpoints E1 to E3 of passengers at different heights. Fig. 7 shows the optical paths of light formed when the rotation axis 126A intersects with the optical axis of light incident on the concave mirror 126. Note that the "optical axis of light" means the optical axis at the center of the beam of light, and the optical paths shown in the drawings indicate the paths of the optical axes of light.

[0090] For example, when the concave mirror 126 is in a predetermined position (a position serving as a reference for rotation), light emitted from the image generator 24 travels along an optical path L0 and is incident on a predetermined point R0 on the concave mirror 126. As illustrated in FIG. 8, a predetermined area A1 centered on the point R0 on the reflecting surface 1261 is illuminated by the light emitted from the image generator 24. The light reflected by the concave mirror 126 travels along an optical path L1 and is incident on a point P1 on the transparent member 18. A portion of the light incident on the point P1 on the transparent member 18 is reflected toward the occupant's viewpoint E1. As a result, a virtual image object I1 is visually recognized by the occupant having the viewpoint E1. As illustrated in FIG. 9, the virtual image object I1 has a rectangle corresponding to the predetermined area A1.

[0091] On the other hand, as illustrated in FIG. 7, when the occupant's viewpoint E2 is higher than viewpoint E1, the concave mirror 126 is rotated toward the image generator 24. Because the rotation axis 126A of the concave mirror 126 intersects with the optical axis of the light incident on the concave mirror 126, even when the concave mirror 126 is rotated, the light emitted from the image generator 24 is incident on a predetermined point R0 on the concave mirror 126. That is, as illustrated in FIG. 8, a predetermined area A2 centered on point R0 on the reflecting surface 1261 is illuminated by the light emitted from the image generator 24, similar to area A1. The light reflected by the concave mirror 126 travels along optical path L2 and is incident on point P2 of the transparent member 18. A portion of the light incident on point P2 of the transparent member 18 is reflected toward the occupant's viewpoint E2. As a result, the virtual image object I2 is visually recognized by the occupant at viewpoint E2.

[0092] When the occupant's viewpoint E3 is located lower than the viewpoint E1, the concave mirror 126 is rotated in the opposite direction to the image generator 24. Because the rotation axis 126A of the concave mirror 126 intersects with the optical axis of the light incident on the concave mirror 126, the light emitted from the image generator 24 is incident on a predetermined point R0 on the concave mirror 126. That is, as illustrated in FIG. 8 , a predetermined area A3 centered on point R0 on the reflecting surface 1261 is illuminated by the light emitted from the image generator 24, similar to the area A1. The light reflected by the concave mirror 126 travels along an optical path L3 and is incident on a point P3 on the transparent member 18. A portion of the light incident on point P3 on the transparent member 18 is reflected toward the occupant's viewpoint E3. As a result, the occupant at the viewpoint E3 visually recognizes a virtual image object I3.

[0093] However, when the viewpoints E2 and E3 of the occupants are at positions different from the viewpoint E1, as will be described later, the optical path length between the points (reflection positions) R2 and R3 on the concave mirror 126 where the light is incident and the points (incident positions) P2 and P3 on the transparent member 18 where the light is incident changes, causing distortions in the displayed virtual image objects I2 and I3.

[0094] For example, in the case of the occupant's viewpoint E2, the optical path length between point R2 on the concave mirror 126 and point P2 on the transparent member 18 is longer than the optical path length between point R1 on the concave mirror 126 where the light is incident and point P1 on the transparent member 18 where the light is incident. This causes distortion in the virtual image object I2, as illustrated in Fig. 10, and the virtual image object I2 has a shape with its upper and lower sides curved in an upwardly convex manner.

[0095] Alternatively, in the case of the occupant's viewpoint E3, the optical path length between point R3 on the concave mirror 126 where the light is incident and point P3 on the transparent member 18 where the light is incident is shorter than the optical path length between point R1 on the concave mirror 126 where the light is incident and point P1 on the transparent member 18 where the light is incident. This causes distortion in the virtual image object I3, as illustrated in Fig. 11, and the virtual image object I3 has a shape where the upper and lower sides are curved in a downwardly convex shape.

[0096] In contrast, the concave mirror 26 according to this embodiment is configured to rotate so that light incident on the concave mirror 26 is irradiated onto a curved surface with a different radius of curvature. For example, the concave mirror 26 is positioned so that the rotation axis 26A does not intersect with the optical axis of the light emitted by the image generator 24 and incident on the concave mirror 26. In this example, as illustrated in FIG. 6 , the reflecting surface 261 has a different radius of curvature along the vertical direction, and the rotation axis 26A is shifted upward with respect to the optical axis of the light incident on the concave mirror 26.

[0097] 12 and 13 show the optical path of light reflected from the concave mirror 26 according to this embodiment. As illustrated in FIGS. 12 and 13, when the concave mirror 26 is at a predetermined position B1 (a position serving as a reference for rotation), light emitted from the image generator 24 travels along an optical path L0 and is incident on a predetermined point R1 on the concave mirror 26. As illustrated in FIG. 14, a predetermined area A11 on the reflecting surface 261, centered at point R1 located below the rotation axis 26A, is illuminated by the light emitted from the image generator 24. The light reflected by the concave mirror 26 travels along an optical path L11 and is incident on a point P11 on the transparent member 18. A portion of the light incident on point P11 on the transparent member 18 is reflected toward the occupant's viewpoint E1. As a result, a virtual image object I11 is visually recognized by the occupant at viewpoint E1. As illustrated in FIG. 15, the virtual image object I11 has a rectangle corresponding to the predetermined area A11.

[0098] On the other hand, as illustrated in FIG. 12, when the occupant's viewpoint E2 is higher than viewpoint E1, the concave mirror 26 is rotated toward the image generator 24. As illustrated in FIG. 13, the concave mirror 26 is displaced from position B1 to position B2, which is rotated by −θ. Because the rotation axis 26A is shifted upward with respect to the optical axis of the light incident on the concave mirror 26, the light emitted from the image generator 24 is incident on point R2, which is located above point R1 on the concave mirror 26. As illustrated in FIG. 14, on the reflecting surface 261, an area A12 centered on point R2 is illuminated by the light emitted from the image generator 24. The light reflected by the concave mirror 26 travels along optical path L12 and is incident on point P12 of the transparent member 18. A portion of the light incident on point P12 of the transparent member 18 is reflected toward the occupant's viewpoint E2. As a result, the virtual image object I12 is visually recognized by the occupant holding the viewpoint E2.

[0099] When the occupant's viewpoint E3 is lower than viewpoint E1, the concave mirror 26 is rotated away from the image generator 24. As illustrated in FIG. 13, the concave mirror 26 is rotated by +θ from position B1 to position B3. Because the rotation axis 26A is shifted upward with respect to the optical axis of the light incident on the concave mirror 26, the light emitted from the image generator 24 is incident on the concave mirror 26 at point R3, which is located below point R1 on the concave mirror 26. As illustrated in FIG. 14, on the reflecting surface 261, an area A13 centered on point R3 is illuminated by the light emitted from the image generator 24. The light reflected by the concave mirror 26 travels along optical path L13 and is incident on point P13 of the transparent member 18. A portion of the light incident on point P13 of the transparent member 18 is reflected toward the occupant's viewpoint E3. As a result, the virtual image object I13 is visually recognized by the occupant having the viewpoint E3.

[0100] When the occupant's viewpoints E2 and E3 are located at positions different from viewpoint E1, the optical path length between points R12 and R13 on the concave mirror 26 where light is incident and points P12 and P13 on the transparent member 18 where light is incident changes. However, the light incident on the reflective surface 261 of the concave mirror 26 is reflected by areas A12 and A13, which have curved surfaces with a different radius of curvature than the radius of curvature of the curved surface of area A11. This reduces distortion of the virtual image objects I12 and I13 caused by changes in the optical path length. Therefore, the display position of the virtual image can be changed according to the position of the occupant's viewpoint E, and changes in the quality of the virtual image are reduced.

[0101] 14, the HUD 20 can be configured so that areas A11 and A12 illuminated by light incident on the concave mirror 26 partially overlap. Similarly, the HUD 20 can be configured so that areas A11 and A13 illuminated by light incident on the concave mirror 26 partially overlap. The areas A11 and A12 or the areas A11 and A13 are examples of a first illumination area and a second illumination area. With this configuration, distortion of the virtual image objects I12 and I13 is reduced, while an increase in the size of the concave mirror 26 is suppressed.

[0102] The HUD 20 may be configured so that the areas A11, A12, and A13 do not overlap. In this case, the size of the concave mirror 26 increases compared to when the areas A11, A12, and A13 partially overlap, but distortion of the virtual image objects I12 and I13 can be further reduced.

[0103] In this embodiment, the reflective surface 261 may be formed so that the radius of curvature of the upper region is larger than the radius of curvature of the lower region. The radius of curvature may be increased upward, or may be changed in stages within a predetermined range.

[0104] According to this configuration, for example, when the optical path length between point R2 on the reflecting surface 261 where the light is incident and point P12 on the transparent member 18 where the light is incident is long, distortion of the virtual image object I12 can be suppressed by reflecting the light in an upper region where the radius of curvature of the reflecting surface 261 is large. For example, as illustrated in FIG. 16 , a virtual image object I12 with reduced distortion on the lower side can be formed.

[0105] For example, when the optical path length between point R3 on the reflecting surface 261 where the light is incident and point P13 on the transparent member 18 where the light is incident is short, distortion of the virtual image object I13 can be suppressed by reflecting the light in a lower region with a smaller radius of curvature of the reflecting surface 261. For example, as illustrated in FIG. 17 , a virtual image object I13 with reduced distortion on the upper side can be formed.

[0106] In the above embodiment, the light emitted from the image generating unit 24 may be configured to be incident on the concave mirror 26 via an optical component such as a plane mirror.

[0107] In the above embodiment, the entire reflective surface 261 is concavely curved. However, the reflective surface 261 may have at least a partial region that is concavely curved, and a curved surface with a different radius of curvature may be formed in the concavely curved region.

[0108] In the above embodiment, the rotation axis 26A is offset upward with respect to the optical axis of the light incident on the concave mirror 26. However, the HUD 20 may be configured so that the rotation axis 26A is offset downward with respect to the optical axis of the light incident on the concave mirror 26.

[0109] In the above embodiment, concave mirror 26 is positioned so that rotation axis 26A does not intersect with the optical axis of the light emitted by image generator 24 and incident on concave mirror 26. However, HUD 20 can be configured to have other configurations as long as concave mirror 26 is configured to rotate so that the light incident on concave mirror 26 is irradiated onto curved surfaces with different radii of curvature.

[0110] In the above embodiment, the light emitted from the image generation unit 24 is reflected by the concave mirror 26 and irradiated onto the transparent member 18. However, for example, the light reflected by the concave mirror 26 may be irradiated onto a combiner (not shown) provided inside the transparent member 18. The combiner is formed, for example, of a transparent plastic disk. A portion of the light irradiated onto the combiner from the image generation unit 24 of the HUD main body 21 is reflected toward the occupant's viewpoint E, similar to when light is irradiated onto the transparent member 18.

[0111] [Third embodiment] A third embodiment of the present invention will now be described with reference to the drawings. FIG. 18 is a schematic diagram of a HUD 20 according to the third embodiment, viewed from the side of a vehicle 1. As shown in FIG. 18, the HUD 20 includes a HUD main body 21. The HUD main body 21 has a housing 22 and an exit window 23. The exit window 23 is made of a transparent plate that transmits visible light. The HUD main body 21 includes an image generation unit (PGU) 30, a control unit 25, a concave mirror 26, and a plane mirror 27 inside the housing 22. The concave mirror 26 is an example of a reflecting unit.

[0112] The image generating device 30 is configured to emit light for generating a predetermined image. The image generating device 30 is fixed to the housing 22. The light emitted from the image generating device 30 is, for example, visible light.

[0113] The control unit 25 controls the operation of each unit of the HUD 20. The control unit 25 is connected to a vehicle control unit (not shown) of the vehicle 1, and generates a control signal for controlling the operation of the image generation device 30 based on, for example, vehicle driving information and surrounding environment information transmitted from the vehicle control unit, and transmits the generated control signal to the image generation device 30. The control unit 25 is equipped with a processor such as a CPU and a memory, and the processor executes a computer program read from the memory to control the operation of the image generation device 30, etc.

[0114] Plane mirror 27 is disposed on the optical path of the light emitted from image generating device 30. Specifically, plane mirror 27 is disposed above image generating device 30 and configured to reflect the light emitted from image generating device 30 toward concave mirror 26. Plane mirror 27 has a flat reflecting surface and reflects the light image emitted from image generating device 30 and formed at the same magnification.

[0115] The concave mirror 26 is disposed on the optical path of the light emitted from the image generating device 30 and reflected by the plane mirror 27. Specifically, the concave mirror 26 is disposed in front of the image generating device 30 and the plane mirror 27 within the housing 22. The concave mirror 26 is configured to reflect the light emitted from the image generating device 30 toward the transparent member 18 (for example, the front window of the vehicle 1). The concave mirror 26 has a reflective surface that is curved concavely. The concave mirror 26 reflects the image of the light emitted from the image generating device 30 and formed at a predetermined magnification. The concave mirror 26 may be configured to be rotatable by a drive mechanism 28.

[0116] In the HUD 20 configured as described above, as illustrated in FIG. 18 , light L1 emitted from the image generating device 30 is reflected by the concave mirror 26 and the plane mirror 27 and emitted from the exit window 23 of the HUD main body 21. The light emitted from the exit window 23 of the HUD main body 21 is irradiated onto the transparent member 18. A portion of the light irradiated from the exit window 23 onto the transparent member 18 is reflected toward the occupant's viewpoint E. As a result, the occupant perceives the light emitted from the HUD main body 21 as a virtual image (predetermined image) formed at a predetermined distance in front of the transparent member 18. In this way, the image displayed by the HUD 20 is superimposed on the real space in front of the vehicle 1 through the transparent member 18, and as a result, the occupant can visually recognize a virtual image object I formed by the predetermined image as floating above the road outside the vehicle.

[0117] When a 2D image (planar image) is formed as the virtual image object I, a predetermined image is projected to become a virtual image at a single distance that is arbitrarily determined. When a 3D image (stereoscopic image) is formed as the virtual image object I, a plurality of predetermined images that may be the same or different from one another are projected to become virtual images at different distances. The distance of the virtual image object I (the distance from the occupant's viewpoint E to the virtual image) can be adjusted as appropriate by adjusting the distance from the image generation device 30 to the occupant's viewpoint E (for example, by adjusting the optical path length between the image generation device 30 and the concave mirror 26).

[0118] Next, the configuration of the image generating device 30 will be described with reference to Fig. 19. As illustrated in Fig. 19, the image generating device 30 includes a light source 241, a lens 242, and a display device 243. The lens 242 is disposed above the light source 241. The display device 243 is disposed above the lens 242. The image generating device 30 may further include a lens holder, a heat sink, and the like.

[0119] The light source 241 is, for example, an LED light source or a laser light source. The LED light source is, for example, a white LED light source. The laser light source is, for example, an RGB laser light source configured to emit red laser light, green laser light, and blue laser light, respectively. The light source 241 is mounted on a substrate 244. The substrate 244 is, for example, a printed circuit board made of an insulator with electrical circuit wiring printed on or inside the substrate.

[0120] Lens 242 is configured to transmit light emitted from light source 241 and emit it toward display device 243. Lens 242 is, for example, an aspherical convex lens in which both incident surface 242A, through which light from light source 241 is incident, and exit surface 242B, through which the incident light is emitted, are formed in a convex shape.

[0121] The display device 243 forms light for generating a predetermined image from the light from the light source 241 that has passed through the lens 242. The display device 243 is, for example, a liquid crystal display, a DMD, or the like.

[0122] The display device 243 is disposed at an angle with respect to a direction perpendicular to the optical axis Ax1 of the light source 241 (the front-to-rear direction in this example). Specifically, an incident surface 243A of the display device 243, onto which light emitted from the lens 242 is incident, is tilted at an angle θ with respect to a direction perpendicular to the optical axis Ax1 of the light source 241. The expression "optical axis of the light source 241" used in this specification means a line of light having the highest brightness among the light emitted from the light source 241. For example, if the light source 241 is an LED light source, the optical axis of the LED light source means a straight line that passes through the center of the light-emitting surface 241A of the LED light source where the brightness is highest and is parallel to the normal to the light-emitting surface 241A.

[0123] The light source 241 is disposed at a position according to the inclination of the display device 243. The position at which the light source 241 is disposed is shifted from a predetermined position. The "predetermined position" is, for example, a position corresponding to the rear focal position of the lens 242. The shift (distance) of the position of the light source 241 from the predetermined position can be set appropriately according to the inclination angle θ of the display device 243 with respect to the direction perpendicular to the optical axis Ax1 of the light source 241. For example, the greater the inclination angle θ of the display device 243, the farther the light source 241 is disposed from the predetermined position.

[0124] The light source 241 is displaced from a predetermined position in a direction in which the incident surface 243A of the display device 243 approaches the exit surface 242B of the lens 242 (forward in FIG. 19 ) due to the tilt of the display device 243. That is, the light source 241 is disposed displaced from the predetermined position in a direction corresponding to the tilt direction of the display device 243. In this example, the optical axis Ax1 of the light source 241 is parallel to the optical axis Ax2 of the lens 242, and the incident surface 243A of the display device 243 is displaced from the optical axis Ax2 to a side closer to the exit surface 242B of the lens 242. For example, when the tilt angle θ is approximately 15 degrees and the light source 241 is an LED light source having a rectangular shape in a planar view with a vertical and horizontal width W of 1 mm, the distance D of displacement of the optical axis Ax1 from the optical axis Ax2 is 0.5 mm.

[0125] 20 , light emitted from the light source 241 of the image generating device 30Z according to the reference embodiment is incident on an incident surface 242A of the lens 242. Since the shape of the lens 242 is an aspherical convex lens, the light emitted from the light source 241 is incident on the lens 242 and emerges from the exit surface 242B as light parallel to the optical axis Ax1, which then enters the display device 243.

[0126] However, because display device 243 is tilted with respect to a direction perpendicular to optical axis Ax1 of light source 241, the amount of light incident on incident surface 243A of display device 243 in region R1 away from exit surface 242B of lens 242 is less than the amount of light incident on region R2 closer to exit surface 242B of lens 242. As a result, there is a risk of uneven light distribution occurring in the light emitted from lens 242 and irradiated onto display device 243.

[0127] In contrast, according to the image generating device 30 of this embodiment, the light source 241 is disposed at a position that is shifted from a predetermined position in accordance with the inclination of the display device 243. As a result, as illustrated in Fig. 21 , a portion of the light that is emitted from the light source 241 and then emitted from the emission surface 242B of the lens 242 is emitted in the direction opposite to the direction of the shift of the light source 241 from the predetermined position (rearward in this example). As a result, it is possible to suppress uneven light distribution of light that is irradiated onto the display device 243 that is inclined with respect to the direction perpendicular to the optical axis Ax1 of the light source 241.

[0128] Furthermore, in this embodiment, the optical axis Ax1 of the light source 241 is parallel to the optical axis Ax2 of the lens 242 but is offset from the optical axis Ax2. With this configuration, the position of the light source 241 is simply shifted on the substrate 244, and therefore uneven light distribution can be suppressed with a simple configuration without changing the shape or orientation of the lens 242.

[0129] The image generating device 30 may include two or more light sources 241 .

[0130] Lens 242 is an aspherical convex lens in which both incident surface 242A and exit surface 242B are formed in a convex shape, but may be a lens having another shape.

[0131] The light emitted from the image generating device 30 is configured to be reflected by the concave mirror 26 and irradiated onto the transparent member 18, but is not limited to this. For example, the light reflected by the concave mirror 26 may be irradiated onto a combiner (not shown) provided inside the transparent member 18. The combiner is formed, for example, from a transparent plastic disk. A portion of the light irradiated onto the combiner from the image generating device 30 of the HUD main body 21 is reflected toward the occupant's viewpoint E, similar to when light is irradiated onto the transparent member 18.

[0132] [Fourth embodiment] A fourth embodiment of the present invention will be described below with reference to the drawings. FIG. 22 is a schematic diagram of a HUD 20 according to the fourth embodiment, viewed from the side of a vehicle 1. As shown in FIG. 22, the HUD 20 includes a HUD main body 21. The HUD main body 21 has a housing 22 and an exit window 23. The exit window 23 is made of a transparent plate that transmits visible light. The HUD main body 21 has an image generation unit (PGU) 24, a control unit 25, and a concave mirror 26. The image generation unit 24, the control unit 25, and the concave mirror 26 are housed in the housing 22. The concave mirror 26 is an example of a reflecting unit.

[0133] The image generation unit 24 is configured to emit light L for generating a predetermined image. The image generation unit 24 is fixed to the housing unit 22. The light emitted from the image generation unit 24 is, for example, visible light.

[0134] The control unit 25 controls the operation of each unit of the HUD 20. The control unit 25 is connected to a vehicle control unit (not shown) of the vehicle 1. The control unit 25 generates a control signal for controlling the operation of the image generation unit 24 based on, for example, vehicle driving information and / or surrounding environment information transmitted from the vehicle control unit, and transmits the generated control signal to the image generation unit 24.

[0135] The control unit 25 is equipped with a processor such as a CPU and a memory. The processor executes a computer program read from the memory to control the operation of the image generation unit 24 and other units. The control unit 25 may be integrated with a vehicle control unit. In this regard, the control unit 25 and the vehicle control unit may be configured as a single electronic control unit.

[0136] The concave mirror 26 is disposed on the optical path of the light L emitted from the image generation unit 24. Specifically, the concave mirror 26 is disposed in front of the image generation unit 24 inside the housing unit 22. The concave mirror 26 is configured to reflect the light L emitted from the image generation unit 24 toward the transparent member 18 (for example, the front window of the vehicle 1). The concave mirror 26 has a reflective surface that is curved concavely. The concave mirror 26 reflects the light image emitted from the image generation unit 24 and formed at a predetermined magnification. The concave mirror 26 can be configured to be rotatable by a drive mechanism (not shown).

[0137] As illustrated in FIG. 22 , when the HUD 20 is attached to the body 19 of the vehicle 1, light L emitted from the image generation unit 24 is emitted diagonally downward and forward toward the concave mirror 26. The light L emitted from the image generation unit 24 is reflected by the concave mirror 26 and emitted from the exit window 23 of the HUD main body 21. The light emitted from the exit window 23 of the HUD main body 21 is irradiated onto the transparent member 18. A portion of the light irradiated from the exit window 23 onto the transparent member 18 is reflected toward the occupant's viewpoint E. As a result, the occupant perceives the light emitted from the HUD main body 21 as a virtual image (predetermined image) formed at a predetermined distance in front of the transparent member 18. In this way, the image displayed by the HUD 20 is superimposed on the real space in front of the vehicle 1 through the transparent member 18, and as a result, the occupant can visually perceive a virtual image object I formed by the predetermined image as floating above the road outside the vehicle.

[0138] 23, the image generating unit 24 includes a light source 241, a lens 242 which is an example of an optical component, a display device 243, and a substrate (wiring substrate) 244. The light source 241 is, for example, an LED light source or a laser light source. The LED light source is, for example, a white LED light source. The laser light source is, for example, an RGB laser light source configured to emit red laser light, green laser light, and blue laser light, respectively. The light source 241 is mounted on the substrate 244.

[0139] The lens 242 may include a prism, a lens, a diffuser, a magnifying glass, or the like as appropriate. In this example, the image generating unit 24 includes a lens as the lens 242. The lens 242 transmits light emitted from the light source 241 and emits the light toward the display device 243. The display device 243 is a liquid crystal display, a DMD (Digital Mirror Device), or the like. The display device 243 forms light for generating a predetermined image using the light from the light source 241 that has transmitted through the lens 242.

[0140] 23 , when the HUD 20 is attached to the vehicle body 19, the optical axis Ax of the light source 241 is inclined downward toward the concave mirror 26. The expression "optical axis of the light source 241" used in this specification means the line of light with the highest brightness among the light emitted from the light source 241. For example, if the light source 241 is an LED light source, the optical axis of the LED light source means a straight line that passes through the center of the light-emitting surface of the LED light source where the brightness is highest and is parallel to the normal to the light-emitting surface.

[0141] The light source 241 generates heat when emitting light. The heat generated by the light source 241 is transferred into the air and rises together with the air A1. Because the optical axis Ax of the light source 241 is inclined downward toward the concave mirror 26, the heat transferred into the air rises together with the air A1 without being blocked by the lens 242 or the display device 243. This makes it possible to provide a HUD 20 with good heat dissipation efficiency. In addition, it is possible to prevent the lens 242 and the display device 243 from being affected by the heat generated by the light source 241.

[0142] The substrate 244 of the image generating unit 24 may have a base substrate made of metal. For example, the base substrate may be made of aluminum. An insulating layer is formed on the base substrate, and a wiring layer is formed on the insulating layer. When the base substrate is made of metal, the substrate 244 functions as a heat dissipation member that dissipates heat generated by the light source 241. In other words, the heat generated by the light source 241 is transferred to the substrate 244 and is efficiently dissipated by the base substrate of the substrate 244.

[0143] 24 , the image generation unit 24 may include a heat sink 245 that dissipates heat generated from the light source 241. The heat sink 245 may be disposed so that at least a portion of the heat sink 245 is located above the light source 241 when the HUD 20 is attached to the vehicle body 19. In this example, the heat sink 245 is provided so as to cover the entire surface of the substrate 244 opposite to the surface on which the light source 241 is mounted.

[0144] Heat generated by the light source 241 is transferred to the heat sink 245 and is efficiently dissipated by the heat sink 245. Furthermore, because a portion of the heat sink 245 is located above the light source 241, the heat transferred from the heat sink 245 into the air rises together with the air A2 without being blocked by the image generation unit 24. This improves the heat dissipation efficiency.

[0145] 25 and 26, the heat sink 245A may have a plurality of fins 245A1. Each of the plurality of fins 245A1 protrudes in the opposite direction to the light emission direction of the light source 241. Each of the plurality of fins 245A1 may be formed so that the length L (FIG. 26) in the protruding direction increases upward when the HUD 20 is attached to the vehicle body 19.

[0146] Heat generated by light source 241 is transferred from heat sink 245A into the air and rises together with air A3. Because the length of the upper portion of fin 245A1 in the protruding direction is long, the heat transferred to heat sink 245A is easily dissipated efficiently from the upper portion of heat sink 245A.

[0147] The number of light sources 241 and the number of fins 245A1 mounted on the substrate 244 are not limited to the form shown in FIG.

[0148] 27 , the housing 22 of the HUD 20A may include an opening 221. The opening 221 may be provided in an upper portion of the housing 22 when the HUD 20A is attached to the body 19 of the vehicle 1. In this example, the opening 221 is located above the image generation unit 24.

[0149] The heat generated by the light source 241 is discharged together with the air A1 from the opening 221 of the housing 22. In particular, when the opening 221 is located above the image generating unit 24, the heat generated by the light source 241 can be quickly discharged together with the air from the opening 221. This improves the heat dissipation efficiency.

[0150] In addition, an opening 222 may be provided in the lower part of the housing part 22. As the flow of the rising air A1 accompanies the intake of air into the housing part 22 through the opening 222, a convection current A4 of the rising air occurs inside the housing part 22, and therefore the heat generated by the light source 241 is easily discharged from the opening 221 together with the air A1.

[0151] In addition to or instead of the opening 222, the HUD 20A may include a fan 29 for convection of air within the housing portion 22. The fan 29 generates a forced convection of air A5 within the housing portion 22, making it easier for heat generated by the light source 241 to be discharged together with the air.

[0152] The image generating unit 24 of the HUD 20A may have a heat sink as illustrated in FIGS.

[0153] The heat sinks 245, 245A are provided so as to cover the entire surface of the substrate 244, and a portion thereof is located below the light source 241. However, the heat sinks 245, 245A may be arranged so that the entire heat sinks 245, 245A are located above the light source 241.

[0154] The light emitted from the image generating unit 24 is configured to be reflected by the concave mirror 26 and irradiated onto the transparent member 18, but is not limited to this. For example, the light reflected by the concave mirror 26 may be irradiated onto a combiner (not shown) provided inside the transparent member 18. The combiner is formed, for example, from a transparent plastic disk. A portion of the light irradiated onto the combiner from the image generating unit 24 of the HUD main body 21 is reflected toward the occupant's viewpoint E, similar to when light is irradiated onto the transparent member 18.

[0155] Although the first to fourth embodiments of the present invention have been described above, it goes without saying that the technical scope of the present invention should not be construed as being limited by the description of these embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications of the embodiments are possible within the scope of the invention described in the claims. The technical scope of the present invention should be determined based on the scope of the invention described in the claims and its equivalents.

[0156] This application is based on Japanese Patent Application No. 2021-060971 filed on March 31, 2021, Japanese Patent Application No. 2021-060972 filed on March 31, 2021, Japanese Patent Application No. 2021-060973 filed on March 31, 2021, and Japanese Patent Application No. 2021-060974 filed on March 31, 2021, the contents of which are incorporated herein by reference.

Claims

1. 1. An image generating device for generating a predetermined image, comprising: an image generating unit that emits light for generating the predetermined image; a first mirror that reflects the light; a bracket for mounting the image generating unit; Equipped with The bracket is a base on which the image generating unit is mounted; a pair of protrusions disposed so as to sandwich the image generating unit and protruding from the base in the direction in which light is emitted from the image generating unit; The first mirror is mounted on the pair of protrusions.

2. each of the pair of protrusions is configured such that a tip thereof is at a certain angle with respect to a surface of the base on which the image generating unit is mounted; The image generating device according to claim 1 , wherein the first mirror is attached to the tip portion.

3. The image generating device according to claim 1 or 2; a second mirror that reflects the light emitted by the image generation unit and reflected by the first mirror so that the light is irradiated onto a transparent member.

4. The image projection device according to claim 3 , wherein a distance between a light exit surface of the image generation unit and a reflecting surface of the first mirror is shorter than a distance between the reflecting surface of the first mirror and a reflecting surface of the second mirror.

Images