Image generation device and image irradiation device

Abstract

This invention provides an image generation device that enables miniaturization of the first mirror, reduces changes in image quality, suppresses uneven distribution of light irradiated onto the display device, and has good heat dissipation efficiency. [Solution] The image generation device (30) includes a lens (242) that transmits light emitted from a light source (241), and a display device (243) that forms light for generating an image using the light transmitted through the lens (242). The display device (243) is tilted with respect to a direction perpendicular to the optical axis of the light source (241), and the position where the light source (241) is placed and a predetermined position are offset by a distance corresponding to the tilt of the display device (243).

Description

Technical Field

[0001] The present invention relates to an image generation device and an image irradiation device.

Background Art

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

[0003] In the future automated driving society, it is expected that visual communication between vehicles and humans will become increasingly important. For example, it is expected that visual communication between a vehicle and the passengers of the vehicle will become increasingly important. In this regard, it is possible to realize visual communication between a vehicle and a passenger by using a head-up display (HUD). A head-up display can realize so-called AR (Augmented Reality) by projecting an image or video onto a windshield or a combiner and superimposing the image on the real space through the windshield or the combiner for the passenger to visually recognize.

[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, a concave mirror, etc.

[0005] Further, Patent Document 2 discloses a head-up display that reflects light for forming an image emitted from an image generation unit by a concave mirror and projects it onto a windshield of a vehicle. A part of the light projected onto the windshield is reflected by the windshield and directed towards the driver's eyes. The driver perceives the reflected light that enters the eyes as a virtual image that appears to be an image of an object on the opposite side (outside the vehicle) across the windshield, with the real object visible through the windshield as the background.

[0006] The concave mirror is configured to be rotatable. The concave mirror rotates 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] Furthermore, Patent Document 3 discloses a head-up display that projects light for forming an image, emitted from an image generation device, onto the vehicle's windshield by reflecting the light with a concave mirror. The image generation device comprises a light source, a lens that transmits light emitted from the light source, and a display device that forms light for generating an image using the light transmitted through the lens.

[0008] Furthermore, Patent Document 4 discloses a head-up display that reflects light used to form an image emitted from an image generation unit onto the vehicle's windshield using a concave mirror. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2020-117106 [Patent Document 2] Japanese Patent Publication No. 2018-205509 [Patent Document 3] Japanese Patent Application Publication No. 2020-170067 [Patent Document 4] International Publication No. 2020 / 110580 [Overview of the project] [Problems that the invention aims to solve]

[0010] In conventional head-up displays, such as the one disclosed in Patent Document 1, the projector device and the plane mirror are fixed separately to the housing, which can sometimes lead to a decrease in the positional accuracy between the projector device (image generation device) and the plane mirror.

[0011] Therefore, the present invention aims to provide an image generation device that improves the positional accuracy between the image generation unit and the first mirror and enables miniaturization of the first mirror, as well as an image irradiation device equipped with the image generation device.

[0012] Furthermore, rotating the concave mirror in accordance with the driver's viewpoint changes the optical path length between the reflection position of light on the concave mirror and the incident position of light on the windshield, thus altering the quality of the virtual image.

[0013] Therefore, the present invention aims 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 reduces changes in image quality.

[0014] Furthermore, in head-up displays such as those described in Patent Document 3, the display device may be positioned at an angle relative to the optical axis of the light source, due to the shape and arrangement of other components such as concave mirrors. In this case, the area of ​​the display device closer to the lens's emission surface is brightly illuminated, while the area of ​​the display device further from the lens's emission surface is dimly illuminated. As a result, uneven light distribution may occur in the light emitted from the lens and irradiated onto the display device.

[0015] Therefore, the present invention aims to provide an image generation device and an image irradiation device that suppress light distribution unevenness when light is irradiated onto a display device that is tilted in a direction perpendicular to the optical axis of a light source.

[0016] Furthermore, in head-up displays such as those described in Patent Document 4, a heat sink is provided, for example, to dissipate the heat generated by the light emission of the light source in the image generation unit, but there is room for improvement in the heat dissipation structure.

[0017] Therefore, the present invention aims to provide an image irradiation device with good heat dissipation efficiency. [Means for solving the problem]

[0018] To achieve one of the above objectives, an image generation apparatus according to one aspect of the present invention is An image generation device for generating a predetermined image, comprising: an image generation unit that emits light for generating the predetermined image; a first mirror that reflects the light; a bracket for attaching the image generation unit; and the first mirror is held by the bracket.

[0019] In addition, an image irradiation device according to one aspect of the present invention includes the above image generation device, and a second mirror that reflects the light so that the light emitted by the image generation unit and reflected by the first mirror is irradiated onto a transmissive member.

[0020] In addition, in order to achieve one of the above objects, an image irradiation device according to one aspect of the present invention is a vehicle image irradiation device configured to display a predetermined image, comprising an image generation unit that emits light for generating the predetermined image, a reflecting portion that is rotatably provided and has a reflecting surface for reflecting the light emitted by the image generation unit, the reflecting surface has curved surfaces with different radii of curvature, and the reflecting portion rotates so that the light incident on the reflecting portion is irradiated onto the curved surfaces with different radii of curvature.

[0021] When the reflecting portion is rotated, the reflection direction of the light reflected by the reflecting surface changes. As a result, the optical path length between the reflection position of the light on the reflecting surface and the incident position of the reflected light on the member on which the reflected light is projected changes, and distortion occurs in the predetermined image. According to the above configuration, the light incident on the reflecting surface is reflected by the curved surfaces with different radii of curvature according to the rotation of the reflecting portion, so that the distortion of the predetermined image caused by the change in the optical path length is reduced. Therefore, the display position of the image can be changed corresponding to the viewpoint position of the occupant, and the change in the quality of the image is reduced.

[0022] Furthermore, in order to achieve one of the above objectives, the image generation apparatus according to one aspect of the present invention is Light source and A lens that transmits light emitted from the aforementioned light source, A display device that generates light for creating an image using light transmitted through the aforementioned lens, It is equipped with, The display device is tilted in a direction perpendicular to the optical axis of the light source. The light source is positioned offset from a predetermined position according to the inclination.

[0023] Furthermore, in order to achieve one of the above objectives, the image irradiation device according to one aspect of the present invention is An image projection device for a vehicle configured to display a predetermined image, The image generation device and, At least one reflecting part that reflects the light emitted by the image generating device, It is equipped with.

[0024] With the configuration described above, a portion of the light emitted from the light source and transmitted through the lens is emitted towards the area of ​​the display device that is far from the lens's emission surface. Therefore, unevenness in the light distribution of the light illuminating the display device, which is tilted in a direction perpendicular to the optical axis of the light source, can be suppressed.

[0025] Furthermore, in order to achieve one of the above objectives, the image irradiation device according to one aspect of the present invention is An image projection device for a vehicle configured to display a predetermined image, An image generation unit equipped with a light source, which 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 mounted on the vehicle body, the optical axis of the light source is inclined downward toward the concave mirror.

[0026] With the configuration described above, the heat generated by the light source is transferred into the air and rises with the air. Since 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 obstructed by the components of the image generation unit. This makes it possible to provide an image irradiation 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, enabling miniaturization of the first mirror, and a head-up display equipped with 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 uneven light distribution of light irradiated onto a display device that is tilted in a direction perpendicular to the optical axis of the light source.

[0030] Furthermore, according to the present invention, an image irradiation device with good heat dissipation efficiency can be provided. [Brief explanation of the drawing]

[0031] [Figure 1] This is a block diagram of a vehicle system equipped with an image generation device and a head-up display (HUD) according to the first embodiment. [Figure 2] Figure 1 is a schematic diagram showing the configuration of the HUD. [Figure 3] Figure 1 is a perspective view showing the image generation device and concave mirror of the HUD. [Figure 4] Figure 1 is a perspective view showing the configuration of the image generation device. [Figure 5] This is a cross-sectional view showing the mounting state of the plane mirror shown in Figure 4. [Figure 6] This is a schematic diagram showing the configuration of a head-up display (HUD) according to the second embodiment. [Figure 7] This diagram illustrates the optical paths of light used to form virtual image objects that appear at different positions corresponding to the crew's viewpoint. [Figure 8] This figure shows the region illuminated by light incident on the concave mirror's reflective surface, as shown in Figure 6. [Figure 9] This diagram shows virtual objects that are visible to the occupant when their viewpoint is at a reference position. [Figure 10] This diagram shows virtual objects that are visible to the crew when their viewpoint is higher than the reference position. [Figure 11] This diagram shows virtual objects that are visible to the crew when their viewpoint is lower than the reference position. [Figure 12] This diagram illustrates the optical paths of light used to form virtual image objects that appear at different positions corresponding to the crew's viewpoint. [Figure 13] This diagram illustrates the optical paths of light used to form virtual image objects that appear at different positions corresponding to the crew's viewpoint. [Figure 14] This figure shows the region illuminated by light incident on the concave mirror's reflective surface, as shown in Figure 6. [Figure 15] This diagram shows virtual objects that are visible to the occupant when their viewpoint is at a reference position. [Figure 16] This diagram shows virtual objects that are visible to the crew when their viewpoint is higher than the reference position. [Figure 17] This diagram shows virtual objects that are visible to the crew when their viewpoint is lower than the reference position. [Figure 18] This is a schematic diagram showing the configuration of a head-up display (HUD) according to the third embodiment. [Figure 19] Figure 18 is a schematic cross-sectional view showing the configuration of the image generation device. [Figure 20] This is a schematic cross-sectional diagram showing the configuration of an image generation device relating to a reference model. [Figure 21]Figure 19 is a schematic cross-sectional diagram showing the optical path of light emitted from a light source in the image generation device. [Figure 22] This is a schematic diagram showing the configuration of a head-up display (HUD) according to the fourth embodiment. [Figure 23] Figure 22 is a schematic diagram illustrating the configuration of the image generation unit of the HUD. [Figure 24] This is a schematic diagram showing another example of the configuration of the image generation unit. [Figure 25] This is a schematic diagram showing another example of the configuration of the image generation unit. [Figure 26] Figure 25 is a perspective view illustrating the configuration of the heatsink. [Figure 27] This is a schematic diagram showing another example of a HUD configuration. [Modes for carrying out the invention]

[0032] [First Embodiment] A first embodiment of the present invention (hereinafter referred to as "this embodiment") will be described with reference to the drawings. In this embodiment, for the sake of explanation, the terms "left-right direction," "up-down direction," and "front-back direction" may be referred to as appropriate. These directions are relative directions set for the HUD (Head-Up Display) 20 shown in Figure 2. Here, the "left-right direction" includes the "left direction" and the "right direction." The "up-down direction" includes the "up direction" and the "down direction." The "front-back direction" includes the "forward direction" and the "backward direction." The left-right direction is not shown in Figure 2, but it is a direction perpendicular to the up-down direction and the front-back direction.

[0033] Referring to Figure 1, a vehicle system 2 equipped with the HUD 20 according to this embodiment will be described. The vehicle 1 on which the vehicle system 2 is installed may be, for example, a vehicle (automobile) capable of driving in autonomous driving mode.

[0034] As shown in Figure 1, the vehicle system 2 comprises 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 comprises 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. Furthermore, the vehicle system 2 includes a HUD 20.

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

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

[0037] 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 to transmit the image data to the vehicle control unit 3. The internal camera 6B is located inside the vehicle 1 and is configured to acquire image data showing the occupants. The internal camera 6B functions, for example, as an eye-tracking camera that tracks the occupant's viewpoint E (described later in Figure 2). The internal camera 6B is located, for example, near the rearview mirror or inside the instrument panel.

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

[0039] HMI8 consists of an input unit that receives input operations from the driver and an output unit that outputs driving information and other data to the driver. The input unit includes the steering wheel, accelerator pedal, brake pedal, and a driving mode selector switch for switching the driving mode of vehicle 1. The output unit is a display (excluding HUD) that displays various driving information.

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

[0041] The wireless communication unit 10 is configured to receive information about other vehicles in the vicinity of vehicle 1 from other vehicles and to transmit information about vehicle 1 to other vehicles (vehicle-to-vehicle communication). The wireless communication unit 10 is also configured to receive infrastructure information from infrastructure equipment such as traffic lights and marker lights and to transmit vehicle 1's driving information to the infrastructure equipment (vehicle-to-infrastructure communication). The wireless communication unit 10 is also configured to receive information about pedestrians from portable electronic devices carried by pedestrians and to transmit vehicle 1's own driving information to the portable electronic devices (vehicle-to-pedestrian communication).

[0042] The storage device 11 is an external storage device such as a hard disk drive (HDD) or an SSD (Solid State Drive). The storage device 11 is configured to output map information and vehicle control programs to the vehicle control unit 3 in response to requests from the vehicle control unit 3.

[0043] The steering actuator 12 is configured to receive a steering control signal from the vehicle control unit 3 and control the steering device 13 when the vehicle 1 is driving in autonomous driving mode. 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 vehicle 1 based on driving status information, surrounding environment information, current location information, map information, etc. The driving modes consist of an automatic driving mode and a manual driving mode. In the automatic driving mode, the driving of vehicle 1 is automatically controlled by the vehicle system 2. On the other hand, in the manual driving mode, steering control signals, accelerator control signals, and brake control signals are generated by the driver's manual operation, so the driving of vehicle 1 is controlled by the driver. The automatic driving modes consist of, for example, a fully automatic driving mode, an advanced driving assistance mode, and a driving assistance mode.

[0045] The HUD20 is configured to display predetermined information (hereinafter referred to as HUD information) as an image directed towards the occupant of the vehicle 1, such that the HUD information is superimposed on the real space outside the vehicle 1 (in particular, the surrounding environment in front of the vehicle 1). The HUD information displayed by the HUD20 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 (in particular, information related to objects existing outside the vehicle 1). The HUD20 is an AR display that functions as a visual interface between the vehicle 1 and the occupant.

[0046] The HUD20 comprises 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 to the occupants of the vehicle 1. The image generating device 30 can, for example, emit light for generating a changing image that changes according to the conditions of the vehicle 1.

[0047] The control unit 25 controls the operation of each part of the HUD 20. The control unit 25 is connected to the vehicle control unit 3 and, for example, generates control signals to control the operation of the image generation device 30 based on vehicle driving information and surrounding environment information transmitted from the vehicle control unit 3, and transmits the generated control signals to the image generation device 30. The control unit 25 is equipped with a processor such as a CPU (Central Processing Unit) and memory, and the processor executes a computer program read from the memory to control the operation of the image generation device 30, etc. 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 be configured as an integrated unit. For example, the vehicle control unit 3 and the control unit 25 may be configured by a single electronic control unit.

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

[0049] As shown in Figure 2, at least a portion of the HUD20 is located inside the vehicle 1. Specifically, the HUD20 is installed in a predetermined location inside the vehicle 1. For example, the HUD20 may be located inside the dashboard of the vehicle 1.

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

[0051] As shown in Figures 2 and 3, the concave mirror 40 is located in front of the image generation device 30 within the housing 22. The concave mirror 40 is positioned on the optical path of the light emitted from the image generation device 30. The concave mirror 40 is configured to reflect the light emitted from the image generation device 30 toward the transparent member 18 (for example, the front windshield of the vehicle 1). The concave mirror 40 has a concave curved reflective surface to form a predetermined image, and reflects the image of the light emitted from the image generation device 30 and formed at a predetermined magnification. A reflective film is formed on the reflective surface of the concave mirror 40 (the surface facing the image generation device 30) by depositing a metal such as aluminum.

[0052] The concave mirror 40 is provided with support shafts 41 on both its left and right sides. The concave mirror 40 is supported by the housing 22 via the support shafts 41. The concave mirror 40 is also rotatable about the support shafts 41, and is configured to change its orientation relative to the image generation device 30 by rotating. The concave mirror 40 has, for example, a drive mechanism 42. The drive mechanism 42 is configured to change the position and orientation of the concave mirror 40 based on a control signal transmitted from the control unit 25.

[0053] The image generation device 30 is positioned within the housing 22, facing the concave mirror 40. Light emitted from the image generation device 30 is reflected by the concave mirror 40 and emitted from the emission window 23 of the HUD main unit 21. The light emitted from the emission window 23 of the HUD main unit 21 is irradiated onto the transparent member 18. A portion of the light irradiated onto the transparent member 18 from the emission window 23 is reflected towards the occupant's viewpoint E. As a result, the occupant perceives the light emitted from the image generation device 30 as a virtual image (a 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 onto the real space in front of the vehicle 1 through the transparent member 18, allowing the occupant to perceive the virtual image object I formed by the predetermined image as floating on the road located outside the vehicle.

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

[0055] When forming a 2D image (planar image) as the virtual image object I, a predetermined image is projected to become a virtual image at a single, arbitrarily defined distance. When forming a 3D image (stereoscopic image) as the virtual image object I, multiple predetermined images, whether identical or different, are projected to become virtual images at different distances. Furthermore, 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 Figures 3 and 4, the image generation apparatus 30 according to this embodiment includes an image generation unit 31, a plane mirror 32 (an example of a first mirror), a bracket 33, and a heat sink 36.

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

[0058] The plane mirror 32 is a component for reflecting light emitted from the image generation unit 31 toward the concave mirror 40. The plane mirror 32 is provided between the image generation unit 31 and the concave mirror 40 in the optical path of the light emitted from the image generation unit 31. The plane mirror 32 is held by the bracket 33 on which the image generation unit 31 is mounted. The plane mirror 32 is positioned at a certain angle with respect to the light emission surface of the image generation unit 31 so as to reflect the light emitted from the image generation 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 generation unit 31) by vapor deposition of a metal such as aluminum. Alternatively, 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 component 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 comprises a base 34 and a pair of protrusions 35A and 35B that protrude from the base 34.

[0060] The base 34 is composed 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 mounted with the image generation unit 31 inserted through this opening 34a. Screw holes 34b for fixing the bracket 33 to the housing unit 22 are provided at both the left and right ends of the base 34. The bracket 33 is fixed to the housing unit 22 such that the upper surface of the base 34 is parallel to the fixing surface of the housing unit 22 (for example, the bottom surface of the housing unit 22).

[0061] The pair of protrusions 35A and 35B are each made of rectangular flat plate members. The pair of protrusions 35A and 35B are positioned to sandwich the image generation unit 31, which is fixed to the center of the base body 34, from the left and right directions. Each protrusion 35A and 35B protrudes from the base body 34 in the direction of light emission from the image generation unit 31, that is, upward towards the HUD 20. Each protrusion 35A and 35B is formed with a slope so that the tip is lower on the rear side than on the front side. A plane mirror 32 is attached to the tip of each protrusion 35A and 35B along the slope 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 left open. The sides of the protruding portions 35A and 35B facing the image generation unit 31 are preferably painted black, for example, so as not to reflect light emitted from the image generation unit 31.

[0062] Figure 5 is a cross-sectional view of the image generation device 30 showing the mounting state of the plane mirror 32 to the bracket 33. As shown in Figure 5, the image generation unit 31 includes a light source 101 mounted on a substrate 102, a lens 103 positioned above the light source 101, and a display device 104 positioned 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 light emitted from the light source 101 and emit it 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 constitutes the light emission surface of the image generation unit 31, which emits the light from the light source 101 that has passed through the lens 103 toward the plane mirror 32.

[0064] As shown in FIG. 4, the tip portions of the respective protruding portions 35A and 35B are inclined so as to have 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 portions of the respective protruding portions 35A and 35B. That is, the plane mirror 32 is attached to the tip portions of the respective protruding portions 35A and 35B so as to have an angle θ1 with respect to the mounting surface of the base 34 on which the image generation unit 31 is mounted.

[0065] Further, the display device 104 which is the light emitting surface of the image generation unit 31 is attached so as to have an angle θ3 with respect to the mounting surface of the base 34 on which the image generation unit 31 is mounted. Thereby, it prevents the 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 as long as it can suppress the reflected light directly incident on the light source 101.

[0066] Note that the angle θ1 formed by the plane mirror 32 and the mounting surface of the base 34 is configured to be larger than the angle θ3 formed by the display device 104 which is the light emitting surface of the image generation unit 31 and the mounting surface of the base 34. That is, the plane mirror 32 is attached so as to have a predetermined angle θ2 with respect to the display device 104. Here, θ2 + θ3 = θ1. Thus, by attaching the plane mirror 32 to the protruding portions 35A and 35B of the bracket 33 so as to have a certain angle θ1, the light emitted from the light source 101 is reflected by the plane mirror 32, further reflected by the concave mirror 40, and irradiated to the transmission 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, when 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 so that L1 < L2.

[0068] As described above, the image generation apparatus 30 of this embodiment comprises 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, with the plane mirror 32 held by the bracket 33. With this configuration, the image generation unit 31 and the plane mirror 32 are integrated by being held by the bracket 33. Therefore, variations in the mounting position of the plane mirror 32 relative to the image generation unit 31 can be suppressed, and the positional accuracy of the plane mirror 32 relative to the image generation unit 31 can be improved. Furthermore, although the plane mirror 32 is a relatively expensive material that undergoes aluminum vapor deposition treatment, etc., according to this embodiment, the positional accuracy of the plane mirror 32 relative to the image generation unit 31 is improved, so the plane mirror 32 can be miniaturized, and component costs can be reduced.

[0069] Furthermore, according to the image generation device 30, the bracket 33 has a base 34 on which the image generation unit 31 is mounted, and a pair of protrusions 35A and 35B that are positioned to sandwich the image generation unit 31 and protrude from the base 34 in the direction of light emission from the image generation unit 31. A plane mirror 32 is mounted on the pair of protrusions 35A and 35B. By using a bracket 33 with such a simple configuration, the positional accuracy of the plane mirror 32 relative to the image generation unit 31 can be improved, and the plane mirror 32 can be miniaturized.

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

[0071] Furthermore, the head-up display 20 of this embodiment (an example of an image projection device) 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 by the image generation unit 31 and reflected by the plane mirror 32 is projected onto the transmissive member 18. With this configuration, by reflecting the light emitted from the image generation unit 31 with multiple mirror members, namely the plane mirror 32 and the concave mirror 40, the optical path length from the image generation unit 31 to the transmissive member 18 within the housing 22 can be increased while maintaining the positional accuracy of the plane mirror 32. This makes it possible to miniaturize the entire head-up display while ensuring the optical path length necessary to generate a virtual image (a predetermined image).

[0072] Furthermore, according to the head-up display 20, the distance L1 between the display device 104, which is the light-emitting surface of the image generation unit 31, and the reflective surface of the plane mirror 32 is configured to be 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, the spread of emitted light when it reaches the plane mirror 32 can be suppressed, and the deviation of the arrival position of the emitted light when it reaches the plane mirror 32 can be suppressed. As a result, the plane mirror 32 can be made even smaller.

[0073] In the above embodiment, the case in which the bracket 33 of the image generation device 30 is formed from a resin material has been described, but it is not limited to this. For example, the bracket 33 may be made of a metal material with high heat dissipation (for example, an aluminum member). With this configuration, the bracket 33 itself can function as a heat sink. In that case, for example, it is not necessary to provide a heat sink 36 as in the above embodiment. In addition to the heat sink 36, or instead of the heat sink 36, for example, heat dissipation fins may be provided on the outer surfaces of the protrusions 35A and 35B.

[0074] Furthermore, although the above embodiment describes a configuration in which the concave mirror 40 is supported by the housing portion 22 of the HUD main body portion 21, the invention is not limited to this. For example, the concave mirror 40 may be supported by the bracket 33 of the image generation device 30. In the case where the concave mirror 40 is supported by the bracket 33 of the image generation device 30, the light emitted from the image generation unit 31 may be reflected by the concave mirror 40 alone and irradiated onto the transmissive member 18 without providing the flat mirror 32.

[0075] Furthermore, in the above embodiment, the front windshield of the vehicle 1 was given as an example of the transparent member 18, but it is not limited to this. For example, the transparent member 18 may be a combiner (not shown) installed on the inside of the front windshield. The combiner is made of, for example, a transparent plastic disc. A portion of the light irradiated onto the combiner from the image generation device 30 of the HUD main unit 21 is reflected towards the occupant's viewpoint E, similar to when light is irradiated onto the front windshield.

[0076] Furthermore, the classification and display format of the vehicle's driving modes may be modified as appropriate in accordance with laws or regulations concerning autonomous driving in each country. Similarly, the definitions of "fully autonomous driving mode," "advanced driving assistance mode," and "driving assistance mode" described in this embodiment are merely examples, and these definitions may be modified as appropriate in accordance with laws or regulations concerning 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 the sake of explanation, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component. Also, 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 backward direction of the illustrated structure. Arrow L indicates the left direction of the illustrated structure. Arrow R indicates the right direction of the illustrated structure. These directions are relative directions set for the HUD20 shown in Figure 6.

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

[0079] The HUD20 functions as a visual interface between vehicle 1 and its occupants. Specifically, it is configured to display predetermined information as a predetermined image so that the information is superimposed on the real space outside vehicle 1 (particularly the surrounding environment in front of vehicle 1). The image may include still images or moving images (video). The information displayed by the HUD20 is, for example, vehicle driving information related to the driving of vehicle 1 and / or surrounding environment information related to the surrounding environment of vehicle 1 (particularly information related to objects existing outside vehicle 1).

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

[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 unit 22. The light emitted from the image generation unit 24 is, for example, visible light. The image generation unit 24, although not shown in detail, 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 prisms, lenses, diffusers, magnifying glasses, etc. as appropriate. The optical components transmit the light emitted from the light source and emit it towards the display device. The display device is 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 a DLP or LCOS system is adopted, the light source of the image generation unit 24 may be an LED light source. Furthermore, when a liquid crystal display system is adopted, the light source of the image generation unit 24 may be a white LED light source.

[0082] The control unit 25 controls the operation of each part of the HUD 20. The control unit 25 is connected to the vehicle control unit (not shown) of the vehicle 1, and generates control signals to control 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 signals to the image generation unit 24. The control unit 25 is equipped with a processor such as a CPU and memory, and the processor executes a computer program read from the memory to control the operation of the image generation unit 24 and other components.

[0083] The concave mirror 26 is positioned on the optical path of light emitted from the image generation unit 24. Specifically, the concave mirror 26 is positioned 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 transmissive member 18 (for example, the front windshield of the vehicle 1). The concave mirror 26 reflects the image of the light emitted from the image generation unit 24 and formed at a predetermined magnification using its reflective surface 261. The concave mirror 26 has a reflective surface 261 that is curved in a concave shape. The reflective surface 261 has curved surfaces with different radii of curvature. For example, the reflective surface 261 may be formed to have different radii of curvature along the vertical direction. The radii of curvature may change continuously or may change in steps at predetermined intervals.

[0084] The drive mechanism 28 is configured to change the position of the concave mirror 26 (the orientation of the reflective surface 261) based on a control signal transmitted from the control unit 25. The concave mirror 26 is displaced to a predetermined position by being rotated about the rotation axis 26A by the drive mechanism 28.

[0085] Light emitted from the image generation unit 24 is reflected by the concave mirror 26 and emitted from the emission window 23 of the HUD main unit 21. The light emitted from the emission window 23 of the HUD main unit 21 is irradiated onto the transparent member 18. A portion of the light irradiated onto the transparent member 18 from the emission window 23 is reflected towards the occupant's viewpoint E. As a result, the occupant perceives the light emitted from the HUD main unit 21 as a virtual image (a 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 onto the real space in front of the vehicle 1 through the transparent member 18, allowing the occupant to perceive the virtual image object I formed by the predetermined image as floating on the road located outside the vehicle.

[0086] When forming a 2D image (planar image) as the virtual image object I, a predetermined image is projected so as to become a virtual image at a single, arbitrarily defined distance. When forming a 3D image (stereoscopic image) as the virtual image object I, multiple predetermined images, which may be identical or different from each other, 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 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 according to the position of the occupant's viewpoint E. For example, the position of the occupant's viewpoint E can be determined by the control unit 25 based on image data acquired by a camera located inside the vehicle 1. The occupant's viewpoint E may be either the viewpoint of the occupant's left eye or the viewpoint of their right eye. Alternatively, viewpoint E may be defined as the midpoint of the line segment connecting the viewpoints of the left eye and 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 reflective surface 261) is displaced, the incident position of the light projected onto the transmissive member 18 changes. As a result, the virtual image object I is displayed at a position corresponding to the occupant's viewpoint E. Note that the position of the occupant's viewpoint E may be determined based on input operations from the occupant.

[0089] Figure 7 is a reference configuration showing the optical path of light reflected from the concave mirror 126 when the display position of virtual image objects I1 to I3 is changed to correspond to the viewpoints E1 to E3 of occupants at different heights. Figure 7 shows the optical path formed when the rotation axis 126A intersects with the optical axis of light incident on the concave mirror 126. Note that "optical axis of light" refers to the axis of light at the center of the beam of light, and the optical path shown in the drawing indicates the path of the optical axis of light.

[0090] For example, when the concave mirror 126 is in a predetermined position (the position that serves as the reference for rotation), light emitted from the image generation unit 24 travels along the optical path L0 and is incident on a predetermined point R0 on the concave mirror 126. As illustrated in Figure 8, on the reflective surface 1261, a predetermined region A1 centered on point R0 is illuminated by the light emitted from the image generation unit 24. The light reflected by the concave mirror 126 travels along the optical path L1 and is incident on point P1 of the transmissive member 18. A portion of the light incident on point P1 of the transmissive member 18 is reflected toward the occupant's viewpoint E1. As a result, the virtual image object I1 is visible to the occupant with viewpoint E1. As illustrated in Figure 9, the virtual image object I1 has a rectangle corresponding to the predetermined region A1.

[0091] On the other hand, as illustrated in Figure 7, when the occupant's viewpoint E2 is higher than viewpoint E1, the concave mirror 126 is rotated toward the image generation unit 24. Since 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 generation unit 24 is incident on a predetermined point R0 on the concave mirror 126. That is, as illustrated in Figure 8, similar to region A1, a predetermined region A2 centered on point R0 is illuminated on the reflective surface 1261 by the light emitted from the image generation unit 24. The light reflected by the concave mirror 126 travels along the optical path L2 and is incident on point P2 of the transmissive member 18. A portion of the light incident on point P2 of the transmissive member 18 is reflected toward the occupant's viewpoint E2. As a result, the virtual image object I2 is visible to the occupant with viewpoint E2.

[0092] When the occupant's viewpoint E3 is lower than viewpoint E1, the concave mirror 126 is rotated to the opposite side from the image generation unit 24. The rotation axis 126A of the concave mirror 126 intersects with the optical axis of the light incident on the concave mirror 126, so the light emitted from the image generation unit 24 is incident on a predetermined point R0 on the concave mirror 126. That is, as illustrated in Figure 8, similar to region A1, a predetermined region A3 centered on point R0 is illuminated on the reflective surface 1261 by the light emitted from the image generation unit 24. The light reflected by the concave mirror 126 travels along the optical path L3 and is incident on point P3 of the transmissive member 18. A portion of the light incident on point P3 of the transmissive member 18 is reflected toward the occupant's viewpoint E3. As a result, the virtual image object I3 is visible to the occupant with viewpoint E3.

[0093] However, if the crew's viewpoints E2 and E3 are in a different position from viewpoint E1, the optical path length between the points (reflection positions) R2 and R3 where light on the concave mirror 126 is incident (incident positions) P2 and P3 where light on the transmissive member 18 is incident changes. This causes distortion 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 transmissive member 18 is longer than the optical path length between point R1 on the concave mirror 126 where light is incident and point P1 on the transmissive member 18 where light is incident. As a result, distortion occurs in the virtual image object I2, as illustrated in Figure 10, and the virtual image object I2 takes on a shape in which the upper and lower sides are curved in an upward convex manner.

[0095] Alternatively, in the case of the crew's viewpoint E3, the optical path length between the point R3 on which light enters the concave mirror 126 and the point P3 on which light enters the transmissive member 18 becomes shorter than the optical path length between the point R1 on which light enters the concave mirror 126 and the point P1 on which light enters the transmissive member 18. As a result, distortion occurs in the virtual image object I3, as illustrated in Figure 11, and the virtual image object I3 takes on a shape that is curved with its upper and lower sides convex downwards.

[0096] In contrast, the concave mirror 26 according to this embodiment is configured to rotate so that the light incident on the concave mirror 26 is directed onto curved surfaces with different radii of curvature. For example, the concave mirror 26 is positioned such that its rotation axis 26A does not intersect with the optical axis of the light emitted by the image generation unit 24 and incident on the concave mirror 26. In this example, as illustrated in Figure 6, the reflective surface 261 has different radii 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] Figures 12 and 13 show the optical path of light reflected from the concave mirror 26 according to this embodiment. As illustrated in Figures 12 and 13, when the concave mirror 26 is in a predetermined position B1 (the position that serves as the reference for rotation), the light emitted from the image generation unit 24 travels along the optical path L0 and is incident on a predetermined point R1 on the concave mirror 26. As illustrated in Figure 14, on the reflective surface 261, a predetermined region A11 centered on point R1, which is located below the rotation axis 26A, is illuminated by the light emitted from the image generation unit 24. The light reflected by the concave mirror 26 travels along the optical path L11 and is incident on point P11 of the transmissive member 18. A portion of the light incident on point P11 of the transmissive member 18 is reflected toward the occupant's viewpoint E1. As a result, the virtual image object I11 is visible to the occupant with viewpoint E1. As illustrated in Figure 15, the virtual image object I11 has a rectangle corresponding to the predetermined region A11.

[0098] On the other hand, as illustrated in Figure 12, if the occupant's viewpoint E2 is higher than viewpoint E1, the concave mirror 26 is rotated toward the image generation unit 24. As illustrated in Figure 13, the concave mirror 26 is displaced to position B2, which is rotated by -θ from position B1. Since 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 generation unit 24 is incident on point R2, which is located above point R1 on the concave mirror 26. As illustrated in Figure 14, on the reflective surface 261, a region A12 centered on point R2 is illuminated by the light emitted from the image generation unit 24. The light reflected by the concave mirror 26 travels along the optical path L12 and is incident on point P12 on the transmissive member 18. A portion of the light incident on point P12 on the transmissive member 18 is reflected toward the occupant's viewpoint E2. As a result, the virtual image object I12 is visible to the occupant with viewpoint E2.

[0099] When the crew's viewpoint E3 is lower than viewpoint E1, the concave mirror 26 is rotated to the opposite side from the image generation unit 24. As illustrated in Figure 13, the concave mirror 26 is rotated by +θ from position B1 to position B3. Since 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 generation unit 24 is incident on point R3, which is located below point R1 on the concave mirror 26. As illustrated in Figure 14, on the reflective surface 261, a region A13 centered on point R3 is illuminated by the light emitted from the image generation unit 24. The light reflected by the concave mirror 26 travels along the optical path L13 and is incident on point P13 on the transmissive member 18. A portion of the light incident on point P13 on the transmissive member 18 is reflected towards the crew's viewpoint E3. As a result, the phantom object I13 is visible to the crew member with viewpoint E3.

[0100] When the crew's viewpoints E2 and E3 are in different positions 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 transmissive member 18 where light is incident changes. However, the light incident on the reflective surface 261 of the concave mirror 26 is reflected by regions A12 and A13, which have curved surfaces with a radius of curvature different from that of region A11. This reduces the distortion of the virtual image objects I12 and I13 caused by the change in optical path length. Therefore, the display position of the virtual image can be changed in accordance with the position of the crew's viewpoint E, and the change in the quality of the virtual image is reduced.

[0101] In this embodiment, as illustrated in Figure 14, the HUD 20 may be configured such that regions A11 and A12 illuminated by light incident on the concave mirror 26 partially overlap. Similarly, the HUD 20 may be configured such that regions A11 and A13 illuminated by light incident on the concave mirror 26 partially overlap. Regions A11 and A12 or regions A11 and A13 are examples of a first illumination region and a second illumination region. With such a configuration, the distortion of the virtual image objects I12 and I13 is reduced while suppressing an increase in the size of the concave mirror 26.

[0102] Furthermore, the HUD20 may be configured so that regions A11, A12, and A13 do not overlap. In this case, although the size of the concave mirror 26 increases compared to the case where regions A11, A12, and A13 partially overlap, the distortion of the virtual image objects I12 and I13 can be further reduced.

[0103] In this embodiment, the reflective surface 261 may be formed such that the radius of curvature of the region located above is larger than the radius of curvature of the region located below. The radius of curvature may increase as it moves upward, or it may change in steps at predetermined intervals.

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

[0105] For example, if the optical path length between the point R3 on which light is incident on the reflective surface 261 and the point P13 on which light is incident on the transmissive member 18 is short, the distortion of the virtual image object I13 can be suppressed by reflecting the light in the lower region where the radius of curvature of the reflective surface 261 is small. For example, as illustrated in Figure 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 generation unit 24 may be configured to enter the concave mirror 26 via an optical component such as a plane mirror.

[0107] In the above embodiment, the reflective surface 261 is curved in a concave shape throughout. However, a configuration can also be adopted in which the reflective surface 261 is curved in a concave shape in at least a portion of its region, and a curved surface with a different radius of curvature is formed in the concave-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 such 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, the concave mirror 26 is positioned such that its rotation axis 26A does not intersect with the optical axis of the light emitted by the image generation unit 24 and incident on the concave mirror 26. However, the HUD 20 may also be configured to have other configurations, provided that the concave mirror 26 is configured to rotate so that the light incident on the concave mirror 26 illuminates curved surfaces with different radii of curvature.

[0110] In the above embodiment, the light emitted from the image generation unit 24 is configured to be 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 made of, for example, a transparent plastic disc. A portion of the light irradiated from the image generation unit 24 of the HUD main body 21 onto the combiner is reflected towards the occupant's viewpoint E, similar to when the 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. Figure 18 is a schematic diagram of the HUD 20 according to the third embodiment as seen from the side of the vehicle 1. As shown in Figure 18, the HUD 20 includes a HUD main body 21. The HUD main body 21 has a housing 22 and an output window 23. The output window 23 is made of a transparent plate that transmits visible light. Inside the housing 22, the HUD main body 21 has an image generating device (PGU) 30, a control unit 25, a concave mirror 26, and a plane mirror 27. The concave mirror 26 is an example of a reflective part.

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

[0113] The control unit 25 controls the operation of each part of the HUD 20. The control unit 25 is connected to the vehicle control unit (not shown) of the vehicle 1, and generates control signals to control 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 signals to the image generation device 30. The control unit 25 is equipped with a processor such as a CPU and memory, and the processor executes a computer program read from the memory to control the operation of the image generation device 30 and other components.

[0114] The plane mirror 27 is positioned in the optical path of the light emitted from the image generation device 30. Specifically, the plane mirror 27 is positioned above the image generation device 30 and is configured to reflect the light emitted from the image generation device 30 toward the concave mirror 26. The plane mirror 27 has a planar reflective surface and reflects the image of the light emitted from the image generation device 30 and formed at the same magnification.

[0115] The concave mirror 26 is positioned in the optical path of light emitted from the image generation device 30 and reflected by the plane mirror 27. Specifically, the concave mirror 26 is positioned in front of the image generation device 30 and the plane mirror 27 within the housing portion 22. The concave mirror 26 is configured to reflect light emitted from the image generation device 30 toward a transmissive member 18 (for example, the front windshield of the vehicle 1). The concave mirror 26 has a concavely curved reflective surface. The concave mirror 26 reflects the image of the light emitted from the image generation 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 Figure 18, light L1 emitted from the image generation device 30 is reflected by the concave mirror 26 and the plane mirror 27 and emitted from the emission window 23 of the HUD main body 21. The light emitted from the emission window 23 of the HUD main body 21 is irradiated onto the transmissive member 18. A portion of the light irradiated onto the transmissive member 18 from the emission window 23 is reflected towards the occupant's viewpoint E. As a result, the occupant perceives the light emitted from the HUD main body 21 as a virtual image (a predetermined image) formed at a predetermined distance in front of the transmissive member 18. In this way, the image displayed by the HUD 20 is superimposed onto the real space in front of the vehicle 1 through the transmissive member 18, allowing the occupant to perceive the virtual image object I formed by the predetermined image as floating on the road located outside the vehicle.

[0117] When forming a 2D image (planar image) as the virtual image object I, the predetermined image is projected to become a virtual image at a single, arbitrarily defined distance. When forming a 3D image (stereoscopic image) as the virtual image object I, multiple predetermined images, which may be identical or different from each other, 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 generation device 30 will be described using Figure 19. As illustrated in Figure 19, the image generation device 30 includes a light source 241, a lens 242, and a display device 243. The lens 242 is positioned above the light source 241. The display device 243 is positioned above the lens 242. The image generation 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 its surface or inside.

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

[0121] The display device 243 generates light for producing a predetermined image using 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 digital display unit (DMD), etc.

[0122] The display device 243 is positioned at an angle with respect to the direction perpendicular to the optical axis Ax1 of the light source 241 (in this example, the front-to-back direction). Specifically, the incident surface 243A of the display device 243, into which light emitted from the lens 242 enters, is tilted by an angle θ with respect to the direction perpendicular to the optical axis Ax1 of the light source 241. In this specification, the expression "optical axis of the light source 241" 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 with the highest brightness on the light-emitting surface 241A of the LED light source and is parallel to the normal of the light-emitting surface 241A.

[0123] The light source 241 is positioned according to the tilt of the display device 243. The position where the light source 241 is positioned is offset from a predetermined position. The "predetermined position" is, for example, the position corresponding to the rear focal point of the lens 242. The offset (distance) of the light source 241 from the predetermined position can be appropriately set according to the tilt angle θ of the display device 243 in the direction perpendicular to the optical axis Ax1 of the light source 241. For example, the larger the tilt angle θ of the display device 243, the further the light source 241 is positioned from the predetermined position.

[0124] The light source 241 is offset from a predetermined position in a direction (forward in Figure 19) where the incident surface 243A of the display device 243 approaches the exit surface 242B of the lens 242 due to the tilt of the display device 243. In other words, the light source 241 is positioned offset from a predetermined position in a direction corresponding to the tilt 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 offset relative to the optical axis Ax2 towards the exit surface 242B of the lens 242. For example, the distance D of the offset of the optical axis Ax1 relative to the optical axis Ax2 is 0.5 mm when the tilt angle θ is approximately 15 [deg] and the light source 241 is a rectangular LED light source in plan view with a width W of 1 mm in both length and width.

[0125] For example, when the light source 241 is positioned at the rear focal point of the lens 242, as illustrated in Figure 20, the light emitted from the light source 241 of the image generation device 30Z according to the reference embodiment enters the 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 enters the lens 242 and enters the display device 243 as light parallel to the optical axis Ax1 from the exit surface 242B.

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

[0127] In contrast, according to the image generation apparatus 30 of this embodiment, the light source 241 is positioned offset from a predetermined position to a position corresponding to the inclination of the display device 243. As a result, as illustrated in Figure 21, a portion of the light emitted from the light source 241 and emitted from the emission surface 242B of the lens 242 is emitted in the opposite direction to the direction of the offset of the light source 241 from its predetermined position (in this example, the backward direction). As a result, uneven distribution of light irradiated onto the display device 243, which is inclined with respect to the direction perpendicular to the optical axis Ax1 of the light source 241, can be suppressed.

[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 offset from the optical axis Ax2. With this configuration, since only the position of the light source 241 on the substrate 244 is shifted, uneven light distribution can be suppressed with a simple configuration without changing the shape or orientation of the lens 242.

[0129] The image generation device 30 may be equipped with two or more light sources 241.

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

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

[0132] [Fourth Embodiment] Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. Figure 22 is a schematic diagram of the HUD 20 according to the fourth embodiment as seen from the side of the vehicle 1. As shown in Figure 22, the HUD 20 includes a HUD main body 21. The HUD main body 21 has a housing 22 and an output window 23. The output 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 reflective part.

[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 part of the HUD 20. The control unit 25 is connected to the vehicle control unit (not shown) of the vehicle 1. For example, the control unit 25 generates control signals to control the operation of the image generation unit 24 based on vehicle driving information and / or surrounding environment information transmitted from the vehicle control unit, and transmits the generated control signals to the image generation unit 24.

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

[0136] The concave mirror 26 is positioned on the optical path of the light L emitted from the image generation unit 24. Specifically, the concave mirror 26 is positioned in front of the image generation unit 24 within the housing 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 windshield of the vehicle 1). The concave mirror 26 has a concavely curved reflective surface. The concave mirror 26 reflects the image of the light emitted from the image generation unit 24 and formed at a predetermined magnification. The concave mirror 26 may be configured to be rotatable by a drive mechanism (not shown).

[0137] As illustrated in Figure 22, when the HUD 20 is mounted on the vehicle body 19 of the vehicle 1, the 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 emission window 23 of the HUD main body 21. The light emitted from the emission window 23 of the HUD main body 21 is irradiated onto the transparent member 18. A portion of the light irradiated onto the transparent member 18 from the emission window 23 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 (a 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 onto the real space in front of the vehicle 1 through the transparent member 18, allowing the occupant to perceive the virtual image object I formed by the predetermined image as floating on the road located outside the vehicle.

[0138] As illustrated in Figure 23, the image generation 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 board) 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, lens, diffuser, magnifying glass, etc., as appropriate. In this example, the image generation unit 24 has a lens as the lens 242. The lens 242 transmits light emitted from the light source 241 and emits it toward the display device 243. The display device 243 is a liquid crystal display, a DMD (Digital Mirror Device), etc. The display device 243 uses the light from the light source 241 that has passed through the lens 242 to generate light for generating a predetermined image.

[0140] As illustrated in Figure 23, with the HUD 20 mounted on the vehicle body 19, the optical axis Ax of the light source 241 is inclined downward toward the concave mirror 26. In this specification, the expression "optical axis of the light source 241" refers to 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 refers to a straight line that passes through the center of the light-emitting surface with the highest brightness and is parallel to the normal of the light-emitting surface.

[0141] The light source 241 generates heat when it emits light. The heat generated by the light source 241 is transferred into the air and rises with the air A1. Since the optical axis Ax of the light source 241 is tilted downward toward the concave mirror 26, the heat transferred into the air rises with the air A1 without being obstructed by the lens 242 or the display device 243. This provides a HUD 20 with good heat dissipation efficiency. In addition, it is possible to suppress the effect of the heat generated by the light source 241 on the lens 242 and the display device 243.

[0142] The substrate 244 of the image generation 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 from the light source 241. That is, the heat generated by the light source 241 is transferred to the substrate 244 and efficiently dissipated by the base substrate of the substrate 244.

[0143] As illustrated in Figure 24, the image generation unit 24 may include a heat sink 245 for dissipating heat generated from the light source 241. The heat sink 245 may be positioned such that at least a portion of it is above the light source 241 when the HUD 20 is mounted on the vehicle body 19. In this example, the heat sink 245 is provided to cover the entire surface of the substrate 244 opposite to the surface on which the light source 241 is mounted.

[0144] The heat generated by the light source 241 is transferred to the heat sink 245, where it is efficiently dissipated. Furthermore, since 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 with the air A2 without being obstructed by the image generation unit 24. This improves the heat dissipation efficiency.

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

[0146] The heat generated by the light source 241 is transferred from the heat sink 245A into the air and rises with the air A3. Because the length of the protrusion at the top of the fin 245A1 is long, the heat transferred to the heat sink 245A is easily and efficiently dissipated from the top of the heat sink 245A.

[0147] Note that the number of light sources 241 and fins 245A1 mounted on the substrate 244 is not limited to the configuration shown in Figure 26.

[0148] As illustrated in Figure 27, the housing portion 22 of the HUD 20A may include an opening 221. The opening 221 may be provided on the upper part of the housing portion 22 when the HUD 20A is attached to the vehicle 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 along with the air A1 through the opening 221 of the housing 22. In particular, when the opening 221 is located above the image generation unit 24, the heat generated by the light source 241 can be quickly discharged along with the air through the opening 221. This improves the heat dissipation efficiency.

[0150] In addition, an opening 222 may be provided at the bottom of the housing 22. As the air A1 rises, air is drawn into the housing 22 through the opening 222, and convection A4 of the rising air is generated inside the housing 22, making it easier for the heat generated by the light source 241 to be discharged from the opening 221 along with the air A1.

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

[0152] The image generation unit 24 of the HUD 20A may have a heat sink, as illustrated in Figures 24 and 25.

[0153] The heatsinks 245 and 245A are provided to cover the entire surface of the substrate 244, with a portion of them located below the light source 241. However, the heatsinks 245 and 245A may be positioned such that their entirety is located above the light source 241.

[0154] The light emitted from the image generation unit 24 is configured to be reflected by the concave mirror 26 and irradiated onto the transparent member 18, but this is not limited to this configuration. 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 may be made of, for example, a transparent plastic disc. A portion of the light irradiated from the image generation unit 24 of the HUD main body 21 onto the combiner is reflected towards the occupant's viewpoint E, similar to when the 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 interpreted 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 to 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 the scope of its equivalents.

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

Claims

1. Light source and A lens that transmits light emitted from the aforementioned light source, A display device that generates light for creating an image using light transmitted through the aforementioned lens, It is equipped with, The display device is tilted in a direction perpendicular to the optical axis of the light source. An image generating device in which the position where the light source is placed and a predetermined position are offset by a distance corresponding to the inclination.

2. The image generating apparatus according to claim 1, wherein the displacement of the position of the light source relative to the predetermined position is set according to the tilt angle of the display device with respect to a direction perpendicular to the optical axis of the light source.

3. The image generating apparatus according to claim 1 or 2, wherein the light source is positioned offset in a direction corresponding to the direction of the inclination.

4. An image projection device for a vehicle configured to display a predetermined image, An image generation apparatus according to any one of claims 1 to 3, At least one reflecting part that reflects the light emitted by the image generating device, An image irradiation device equipped with the following features.

Images