Light emitting device, head-up display, vehicle lighting fixture, and projector

Abstract

To provide a light emitting device which can prevent generation of heat damage due to outside light without compromising a light emission function.SOLUTION: A light emitting device (20) includes: a light source (24); an optical member (27) for transmitting or reflecting light emitted from the light source (24) to enlarge the light and radiating the light to the outside; and an optical isolator (70) for transmitting light and also preventing outside light from the outside from entering the light source (24).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a light emitting device, a head-up display, a vehicle lamp, and a projector. [Background technology]

[0002] It is expected that on public roads there will be a mixture of vehicles operating in autonomous mode and vehicles operating in manual mode.

[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] As an example of a head-up display, Patent Document 1 discloses a display device equipped with an optical system for displaying a three-dimensional virtual image using a transparent display medium. The display device projects light onto the windshield or combiner into the driver's field of vision. Some of the projected light passes through the windshield or combiner, while other parts are reflected by the windshield or combiner. This reflected light is directed toward the driver's eyes. The driver perceives the reflected light as a virtual image that appears to be an image of an object on the other side of the windshield or combiner (outside the vehicle) against the background of real objects visible through the windshield or combiner.

[0005] Furthermore, if external light such as sunlight enters the interior of a head-up display, the external light is concentrated on the display, causing a local temperature rise, which may lead to a disturbance in the image display or thermal damage to the display. To prevent such problems, configurations that increase the heat dissipation of the display and configurations that provide a plate that reflects infrared rays between the display and the reflective part are known (see Patent Document 2). However, Patent Document 2 requires a separate component to suppress the temperature rise of the display, which leads to high costs.

[0006] The display device has a reflector that reflects the light image formed on the screen toward the windshield or combiner. When a concave mirror is used as the reflector, a high-resolution concave mirror is required, which leads to an increase in the cost of the display device.

[0007] Furthermore, there is room for improvement in the configuration of existing head-up displays to expand the display range of the virtual image (picture). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2018-45103 [Patent Document 2] Japanese Patent Publication No. 2005-313733 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present disclosure is to provide a light emitting device, a head-up display, a vehicle lamp, and a projector that can prevent heat damage caused by external light without reducing the light emitting function.

[0010] An object of the present disclosure is to provide a head-up display that can realize a reflector at low cost without significantly degrading the image quality of a virtual image.

[0011] An object of the present disclosure is to provide a head-up display that can realize a reflector at low cost.

[0012] An object of the present disclosure is to provide a head-up display that can expand the image display range at low cost. [Means for solving the problem]

[0013] A light output device according to one aspect of the present disclosure includes: A light source and an optical member that transmits or reflects light emitted from the light source to magnify the light and irradiate it to the outside; and an optical isolator that is capable of transmitting the light while preventing the external light from entering the light source.

[0014] According to the above configuration, it is possible to provide a light emitting device that can prevent the occurrence of heat damage caused by external light entering the light source without deteriorating the light emitting function.

[0015] A head-up display according to one aspect of the present disclosure includes: A head-up display provided in a vehicle and including the light emitting device described above, the light emitting device is configured to display a predetermined image toward an occupant of the vehicle; The optical member transmits or reflects the light emitted by the light source so that the light is irradiated onto a windshield or a combiner, The optical isolator is disposed at a position where the light passes between the light source and the optical member, or between the optical member and the windshield or the combiner.

[0016] According to the above configuration, it is possible to provide a head-up display that can prevent heat damage caused by external light entering the light source without reducing the light emission function.

[0017] A vehicle lamp according to one aspect of the present disclosure includes: A vehicle lamp provided in a vehicle and including the light emitting device described above, the light emitting device is configured to emit light to an area around the vehicle; The optical isolator is disposed at a position where the light passes between the light source and the optical member or between the optical member and the outer lens of the vehicle lamp.

[0018] According to the above configuration, it is possible to provide a vehicle lamp that can prevent heat damage caused by external light entering the light source without reducing the light emission function.

[0019] A projector according to one aspect of the present disclosure includes: A projector including the light output device described above, the light output device is configured to display a predetermined image on an object external to the projector; The optical isolator is disposed at a position where the light passes between the light source and the optical member or between the optical member and the object.

[0020] According to the above configuration, it is possible to provide a projector that can prevent heat damage caused by external light entering the light source without reducing the light output function.

[0021] A head-up display according to one aspect of the present disclosure includes: A head-up display provided in a vehicle and configured to display a predetermined image toward an occupant of the vehicle, an image generating unit that emits first light for generating a first image of the predetermined images and second light for generating a second image of the predetermined images; a reflecting unit that reflects the first light and the second light emitted by the image generating unit so that the first light and the second light are irradiated onto a windshield or a combiner, the reflecting portion has a reflecting surface including a first reflecting area that reflects the first light and a second reflecting area that reflects the second light, The first reflective area has a first surface roughness, and the second reflective area has a second surface roughness that is rougher than the first surface roughness.

[0022] According to the above configuration, the second reflective region has a surface roughness greater than that of the first reflective region. Therefore, the second reflective region can be formed at a lower cost than the first reflective region. Meanwhile, the first reflective region has a surface roughness less than that of the second reflective region. Therefore, the first image can be recognized as a high-quality virtual image. Therefore, the reflective portion can be realized at a low cost without significantly degrading the image quality of the virtual image.

[0023] A head-up display according to one aspect of the present disclosure includes: A head-up display provided in a vehicle and configured to display a predetermined image toward an occupant of the vehicle, an image generating unit that emits first light for generating a first image of the predetermined images and second light for generating a second image of the predetermined images; a reflecting unit that reflects the first light and the second light emitted by the image generating unit so that the first light and the second light are irradiated onto a windshield or a combiner, The reflecting section includes a concave mirror that reflects the first light and a plane mirror that reflects the second light.

[0024] According to the above configuration, since the reflecting section is made up of a concave mirror and a plane mirror, the reflecting section can be realized at low cost.

[0025] A head-up display according to one aspect of the present disclosure includes: A head-up display provided in a vehicle and configured to display a predetermined image toward an occupant of the vehicle, an image generating unit that emits light for generating the predetermined image; a reflecting unit that reflects the light emitted by the image generating unit so that the light is irradiated onto a windshield or a combiner, a first region is a region on the light output surface of the image generating unit that can form a rectangular maximum display range in which a first image that is a part of the predetermined image is displayed, and a second region is a region other than the first region; A second image different from the first image is displayed by the light emitted from the second region outside the maximum display range in which the first image can be displayed by the light emitted from the first region.

[0026] According to the above configuration, the second image can be displayed outside the maximum rectangular display range in which the first image is displayed, thereby making it possible to widen the image display range compared to conventional methods. [Effects of the Invention]

[0027] According to the present disclosure, it is possible to provide a light emitting device, a head-up display, a vehicle lamp, and a projector that can prevent heat damage caused by external light without reducing the light emitting function.

[0028] According to the present disclosure, it is possible to provide a head-up display that can realize a reflector at low cost without significantly degrading the image quality of the virtual image.

[0029] According to the present disclosure, it is possible to provide a head-up display that can realize a reflector at low cost.

[0030] According to the present disclosure, it is possible to provide a head-up display that can expand the image display range at low cost. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a block diagram of a vehicle system equipped with a head-up display (HUD) as a light irradiation device according to an embodiment of the present invention. [Figure 2] FIG. 1 is a schematic diagram of a HUD according to a first embodiment. [Figure 3] FIG. 3 is a cross-sectional view of an optical isolator included in the HUD of FIG. 2. [Figure 4] FIG. 4 is a schematic diagram for explaining the magnetic field of the optical isolator of FIG. 3. [Figure 5] 4 is a schematic diagram illustrating the function of the optical isolator in FIG. 3. FIG. [Figure 6] 4 is a schematic diagram illustrating the function of the optical isolator in FIG. 3. FIG. [Figure 7] FIG. 10 is a diagram showing a state in which external light is incident on a HUD that does not include an optical isolator. [Figure 8] FIG. 3 is a diagram showing a state in which external light is incident on the HUD of FIG. 2. [Figure 9] FIG. 10 is a schematic diagram of a HUD according to a first modified example. [Figure 10] FIG. 10 is a schematic diagram of a HUD according to a second modified example. [Figure 11] FIG. 10 is a vertical cross-sectional view of a vehicle lamp that also serves as a light irradiation device according to a second embodiment. [Figure 12] FIG. 10 is a schematic diagram of a HUD according to a third embodiment. [Figure 13A] 13 is a schematic diagram illustrating the concave mirror of FIG. 12. FIG. [Figure 13B] 13B is a cross-sectional view of the concave mirror of FIG. 13A taken along line IIIB-IIIB and viewed from the direction of the arrows. [Figure 13C] FIG. 13C is a partially enlarged view showing region IIIC in FIG. 13B. [Figure 14] 3 is a schematic diagram illustrating an example of an area on the windshield that is irradiated with light emitted by the HUD. FIG. [Figure 15A] 10A and 10B are schematic diagrams illustrating concave mirrors according to modified examples. [Figure 15B] 15B is a cross-sectional view of the concave mirror of FIG. 15A taken along line VB-VB and viewed from the direction of the arrows. [Figure 16A] FIG. 10 is a schematic diagram illustrating a concave mirror according to a fourth embodiment. [Figure 16B] 16B is a cross-sectional view of the concave mirror of FIG. 16A taken along line VIB-VIB and viewed from the direction of the arrows. [Figure 17]3 is a schematic diagram illustrating an example of an area on the windshield that is irradiated with light emitted by the HUD. FIG. [Figure 18] FIG. 10 is a schematic diagram of a HUD according to a fifth embodiment. [Figure 19] FIG. 2 is a schematic diagram illustrating a reflecting section viewed from an image generating section. [Figure 20] 3 is a schematic diagram illustrating an example of an area on the windshield that is irradiated with light emitted by the HUD. FIG. [Figure 21] FIG. 10 is a schematic diagram of a HUD according to a sixth embodiment. [Figure 22] FIG. 13 is a schematic diagram of a HUD according to a seventh embodiment. [Figure 23] FIG. 2 is a schematic diagram illustrating a reflecting section viewed from an image generating section. [Figure 24] 3 is a schematic diagram illustrating an example of an area on the windshield that is irradiated with light emitted by the HUD. FIG. [Figure 25] FIG. 13 is a schematic diagram of a HUD according to an eighth embodiment. [Figure 26] FIG. 13 is a schematic diagram showing the configuration of a HUD according to a ninth embodiment. [Figure 27A] 10 is a diagram showing an example of an image of an exit surface generated by an image generating unit of a HUD according to a comparative example. FIG. [Figure 27B] 27B is a diagram showing the exit surface image shown in FIG. 27A displayed as a virtual image. [Figure 28] FIG. 23 is a diagram showing an example of an image of an exit surface generated by an image generating unit of a HUD according to a ninth embodiment. [Figure 29] FIG. 29 is a diagram showing the exit surface image shown in FIG. 28 displayed as a virtual image. [Figure 30] FIG. 10 is a schematic diagram showing a HUD according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. For the sake of convenience, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component.

[0033] Furthermore, in the description of 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.

[0034] First, a vehicle system 2 equipped with a HUD 20 according to this embodiment will be described below with reference to Fig. 1. Fig. 1 is a block diagram of the vehicle system 2. A vehicle 1 equipped with the vehicle system 2 is a vehicle (automobile) capable of running in an autonomous driving mode.

[0035] 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.

[0036] The vehicle control unit 3 is configured to control the driving of the vehicle 1. The vehicle control unit 3 is configured, for example, by at least one electronic control unit (ECU). The electronic control unit includes a computer system (e.g., a system on a chip (SoC)) having one or more processors and a memory, and an electronic circuit configured of active elements such as transistors and passive elements such as resistors. The processor includes, for example, at least one of a central processing unit (CPU), a micro processing unit (MPU), a graphics processing unit (GPU), and a tensor processing unit (TPU). The CPU may be configured with multiple CPU cores. The GPU may be configured with multiple GPU cores. The memory includes a read-only memory (ROM) and a random access memory (RAM). A vehicle control program may be stored in the ROM. For example, the vehicle control program may include an artificial intelligence (AI) program for autonomous driving. The AI ​​program is a program (trained model) constructed by supervised or unsupervised machine learning (particularly, deep learning) using a multi-layer neural network. The RAM may temporarily store a vehicle control program, vehicle control data, and / or surrounding environment information indicating the surrounding environment of the vehicle 1. The processor may be configured to load a program specified from various vehicle control programs stored in the ROM onto the RAM and execute various processes in cooperation with the RAM. The computer system may also be configured using a non-von Neumann computer such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). The computer system may also be configured using a combination of a von Neumann computer and a non-von Neumann computer.

[0037] 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.

[0038] The camera 6 is a camera including an imaging element such as a CCD (Charge-Coupled Device) or a CMOS (Complementary Metal-Oxide Semiconductor), etc. 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 environment surrounding the vehicle 1 and then transmit the image data to the vehicle control unit 3. The vehicle control unit 3 acquires surrounding environment information based on the transmitted image data. Here, the surrounding environment information may include information about objects (pedestrians, other vehicles, signs, etc.) present outside the vehicle 1. For example, the surrounding environment information may include information about the attributes of objects present outside the vehicle 1 and information about the distance and position of the objects relative to the vehicle 1. The external camera 6A may be configured as a monocular camera or a stereo camera.

[0039] 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.

[0040] 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 detect the surrounding environment of the vehicle 1. In particular, 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. The vehicle control unit 3 identifies surrounding environment information based on the transmitted 3D mapping data.

[0041] 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.

[0042] 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.

[0043] The wireless communication unit 10 is configured to receive information (e.g., travel information, etc.) about other vehicles around the vehicle 1 from the other vehicles and transmit information (e.g., travel information, etc.) 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 travel 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 (smartphones, tablets, wearable devices, etc.) carried by pedestrians and transmit travel information about the vehicle 1 to the portable electronic devices (pedestrian-to-vehicle communication). The vehicle 1 may communicate directly with other vehicles, infrastructure facilities, or portable electronic devices in an ad hoc mode, or may communicate via an access point. The vehicle 1 may also communicate with other vehicles, infrastructure facilities, or portable electronic devices via a communication network (not shown). The communication network includes at least one of the Internet, a local area network (LAN), a wide area network (WAN), and a radio access network (RAN). The wireless communication standard may be, for example, Wi-Fi (registered trademark), Bluetooth (registered trademark), ZigBee (registered trademark), LPWA, DSRC (registered trademark), or Li-Fi. Vehicle 1 may also communicate with other vehicles, infrastructure facilities, or portable electronic devices using a fifth-generation mobile communication system (5G).

[0044] The storage device 11 is an external storage device such as a hard disk drive (HDD) or a solid state drive (SSD). Two-dimensional or three-dimensional map information and / or a vehicle control program may be stored in the storage device 11. For example, the three-dimensional map information may be composed of 3D mapping data (point cloud data). The storage device 11 is configured to output the map information and the vehicle control program to the vehicle control device 3 in response to a request from the vehicle control device 3. The map information and the vehicle control program may be updated via the wireless communication unit 10 and a communication network.

[0045] When the vehicle 1 is traveling in the autonomous driving mode, the vehicle control unit 3 automatically generates at least one of a steering control signal, an accelerator control signal, and a brake control signal based on traveling condition information, surrounding environment information, current position information, map information, etc. The steering actuator 12 is configured to receive the steering control signal from the vehicle control unit 3 and control the steering device 13 based on the received steering control signal. The brake actuator 14 is configured to receive the brake control signal from the vehicle control unit 3 and control the brake device 15 based on the received brake control signal. The accelerator actuator 16 is configured to receive the accelerator control signal from the vehicle control unit 3 and control the accelerator device 17 based on the received accelerator control signal. In this way, the vehicle control unit 3 automatically controls the traveling of the vehicle 1 based on the traveling condition information, surrounding environment information, current position information, map information, etc. In other words, in the autonomous driving mode, the traveling of the vehicle 1 is automatically controlled by the vehicle system 2.

[0046] On the other hand, when the vehicle 1 is traveling in the manual driving mode, the vehicle control unit 3 generates a steering control signal, an accelerator control signal, and a brake control signal in accordance with the driver's manual operation of the accelerator pedal, the brake pedal, and the steering wheel. In this way, in the manual driving mode, the steering control signal, the accelerator control signal, and the brake control signal are generated by the driver's manual operation, so that the traveling of the vehicle 1 is controlled by the driver.

[0047] As described above, the driving modes include an autonomous driving mode and a manual driving mode. The autonomous driving modes include, for example, a fully autonomous driving mode, an advanced driving assistance mode, and a driving assistance mode. In the fully autonomous driving mode, the vehicle system 2 automatically performs all driving control, including steering control, braking control, and accelerator control, and the driver is not in a state where he or she can drive the vehicle 1. In the advanced driving assistance mode, the vehicle system 2 automatically performs all driving control, including steering control, braking control, and accelerator control, and the driver is in a state where he or she can drive the vehicle 1 but does not drive the vehicle 1. In the driving assistance mode, the vehicle system 2 automatically performs some driving control, including steering control, braking control, and accelerator control, and the driver drives the vehicle 1 with the driving assistance of the vehicle system 2. On the other hand, in the manual driving mode, the vehicle system 2 does not automatically perform driving control, and the driver drives the vehicle 1 without the driving assistance of the vehicle system 2.

[0048] The HUD 20 is configured to display predetermined information (hereinafter referred to as HUD information) as an image toward the occupant 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 occupant.

[0049] 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 picture generation unit (PGU) 24 and a control unit 25. The image generating unit 24 is configured to emit light for generating a predetermined image to be displayed toward the occupants of the vehicle 1.

[0051] The control unit 25 is configured to control the operation of each unit of the HUD 20. The control unit 25 is connected to the vehicle control unit 3, and controls the operation of each unit of the HUD 20, such as the image generation unit 24, based on vehicle driving information, surrounding environment information, and the like transmitted from the vehicle control unit 3. 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 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.

[0052] (First embodiment) FIG. 2 is a schematic diagram of the HUD 20 according to the first embodiment, as viewed from the side of the vehicle 1. As shown in FIG. 2, the HUD 20 includes a HUD main body 21 (an example of a light emitting device). 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 light. The HUD main body 21 includes, inside the housing 22, a picture generation unit (PGU) 24, a plane mirror 26 (an example of a reflecting unit), a concave mirror 27 (an example of a reflecting unit), an optical isolator 70, and a control board 29.

[0053] The image generation unit 24 is configured to emit light for generating a predetermined image to be displayed to the occupants of the vehicle 1. Although detailed illustration is omitted, the image generation unit 24 includes a light source, optical components, and a display device. The light source is, for example, a laser light source or an 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 (Digital Mirror Device), 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 method or the LCOS method is adopted, the light source may be an LED light source. Note that when the liquid crystal display method is adopted, the light source may be a white LED light source.

[0054] Plane mirror 26 is disposed in a position where it can reflect the light emitted from image generator 24 in a direction toward concave mirror 27. Note that a lens, for example, may be used as an optical element instead of plane mirror 26. When a lens is used, it is preferable to adjust the positional relationship between image generator 24, the lens, and concave mirror 27 so that the light emitted from image generator 24 passes through the lens and heads toward concave mirror 27.

[0055] The concave mirror 27 is disposed on the optical path of the light emitted from the image generator 24 and reflected by the plane mirror 26. The concave mirror 27 is configured to reflect the light emitted from the image generator 24 toward the windshield 18 (e.g., the front window of the vehicle 1). The concave mirror 27 has a reflective surface that is concavely curved to form a predetermined image, and reflects the light image emitted from the image generator 24 and formed thereon at a predetermined magnification. That is, the concave mirror 27 reflects the light emitted from the image generator 24, thereby magnifying the light and irradiating it outside the HUD 20. The concave mirror 27 has a drive mechanism (not shown). The drive mechanism can rotate the orientation of the concave mirror 27 based on a control signal transmitted from the control board 29.

[0056] Control board 29 constituting control unit 25 is configured to control the operation of image generation unit 24. Control board 29 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 image generation unit 24. For example, control board 29 generates a control signal for controlling the operation of image generation unit 24 based on vehicle driving information, surrounding environment information, etc. transmitted from vehicle control unit 3, and transmits the generated control signal to image generation unit 24. Control board 29 may also control concave mirror 27 to change its orientation.

[0057] The optical isolator 70 is an optical filter disposed between the concave mirror 27 and the exit window 23. The optical isolator 70 is provided at a position through which light emitted from the image generation unit 24, reflected by the plane mirror 26 and the concave mirror 27, and directed toward the windshield 18 passes. The optical isolator 70 is also provided at a position through which external light that enters the interior of the vehicle 1 from the outside, is reflected by the concave mirror 27 and the plane mirror 26, and directed toward the image generation unit 24 passes.

[0058] FIG. 3 is a cross-sectional view of the optical isolator 70. The optical isolator 70 is a member that can transmit light emitted from the image generation unit 24, while blocking external light from outside the vehicle 1 to prevent the external light from entering the image generation unit 24. As shown in FIGS. 2 and 3 , the optical isolator 70 includes two polarizers (a first polarizing plate 71 and a second polarizing plate 72) and a Faraday element 73. The Faraday element 73 is disposed between the first polarizing plate 71 and the second polarizing plate 72 on the optical path of the light emitted from the image generation unit 24.

[0059] The first polarizing plate 71 (an example of a first polarizer) and the second polarizing plate 72 (an example of a second polarizer) transmit only light polarized in a specific direction and are, for example, linear polarizers that align the vibration direction of transmitted light in a certain direction. Examples of the first polarizing plate 71 and the second polarizing plate 72 that can be used include polarizing glass, a polarizing beam splitter (PBS), a prism-type polarizer using birefringent crystals, and a wire-grid polarizer. The first polarizing plate 71 is arranged to transmit light having only a component with a specific vibration direction. The second polarizing plate 72 is arranged to transmit light having only a component with a vibration direction different from the specific vibration direction component transmitted by the first polarizing plate 71. The first polarizing plate 71 and the second polarizing plate 72 may be configured as absorptive polarizing plates that absorb and remove polarization components in unwanted directions from the optical path, or as reflective polarizing plates that reflect polarization components in unwanted directions back toward the incident direction. However, when the optical isolator 70 is disposed at the position of the exit window 23 of the HUD main body 21 as in this embodiment, it is preferable to use an absorptive polarizing plate that is unlikely to cause glare due to light reflected by the optical isolator 70. The first polarizing plate 71 and the second polarizing plate 72 may each be provided with a filter for blocking at least one of ultraviolet light and infrared light.

[0060] The Faraday element 73 includes a housing 74, a Faraday rotator 75, and a magnet 76. The housing 74 is formed in a cylindrical shape and houses the Faraday rotator 75 and the magnet 76 therein. The housing 74 is made of a magnetic material such as Fe. The housing 74 not only protects the Faraday rotator 75 and the magnet 76, but also functions as a yoke that guides the magnetic flux of the magnet 76.

[0061] The Faraday rotator 75 is composed of a base layer 75A, a Faraday layer 75B provided on the base layer 75A, and a protective layer 75C provided on the Faraday layer 75B. The base layer 75A is made of a transparent material that is resistant to distortion, such as glass or a crystalline material.

[0062] The Faraday layer 75B is a layer made of a material that exhibits the Faraday effect, which rotates the polarization direction of light when a magnetic field is applied. The material that makes up the Faraday layer 75B is not particularly limited, but examples thereof include bismuth-substituted rare earth iron garnet ((RBi)FeO 12 ), yttrium iron garnet (Y3Fe5O 12 ), terbium gallium garnet (Tb3Ga5O 12 ), Faraday rotation glass, etc. may be used. Note that a material having a nanogranular structure consisting of a fluoride matrix and magnetic metal granules of nm size may be used as the Faraday layer 75B. Examples of materials having a nanogranular structure include Fe 26 Al 28 F 46 , Fe 13 Co 10 Al 22 F 55 , Fe 25 Y 23 F 52 , Fe 21 Co 14 Y 24 F 41 , Bi-YIG, etc.

[0063] The protective layer 75C is a layer provided to cover the faraday layer 75B in order to prevent deterioration of the faraday layer 75B. The protective layer 75C is made of, for example, SiO2.

[0064] The magnet 76 is used to apply a magnetic field to the Faraday rotator 75. The magnet 76 is arranged around the Faraday rotator 75. For example, a single cylindrical magnet may be used as the magnet 76. In the case of a cylindrical magnet, the Faraday rotator 75 is arranged at a position corresponding to the center hole of the cylindrical magnet. For example, a permanent magnet may be used as the magnet 76. Note that the magnet 76 may also be a pair of magnets with a Faraday rotator placed between them. When using a pair of magnets, the magnetic fields applied to the Faraday rotator 75 must be in the same direction.

[0065] FIG. 4 is a schematic diagram for explaining the magnetic field (magnetic field) applied to the Faraday element 73 of the optical isolator 70. As shown in FIG. As shown in FIG. 4, the magnet 76 is arranged so that, for example, one end of the magnet 76 that contacts the housing 74 is an S pole and the other end (the end closer to the Faraday rotator 75) is an N pole. The housing 74, which is made of a magnetic material, is formed so that both ends (end faces 74A and 74B) are inward in a cross-sectional view, i.e., so that it has a U-shape facing each other. Therefore, magnetic field lines F emanating from the N pole side of the magnet 76 travel toward the end face 74A of the housing 74 that faces the second polarizer 72, pass through the housing 74 from the end face 74A, exit from the end face 74B that faces the first polarizer 71, and return to the N pole. Thus, the magnetic field lines F formed by the magnet 76 and the housing 74 pass through the Faraday rotator 75 along the direction D from the first polarizer 71 to the second polarizer 72. In this way, the Faraday rotator 75 is at least partially covered by the housing 74 made of a magnetic material. The housing 74 is configured to have a so-called yoke structure. This allows the Faraday rotator 75 to be placed in a magnetic field in a desired direction as indicated by magnetic field lines F. Furthermore, since leakage of the magnetic field outside the housing 74 can be suppressed, adverse effects on members other than the Faraday element 73 can be prevented.

[0066] Next, the operation of the optical isolator 70 will be described with reference to Fig. 2 and Figs. 5 to 8. Figs. 5 and 6 are schematic diagrams illustrating the function of the optical isolator 70. Fig. 7 is a diagram illustrating a state in which external light is incident on a HUD that does not include an optical isolator. Fig. 8 is a diagram illustrating a state in which external light is incident on the HUD 20 of this embodiment. 5 and 6, for ease of explanation, the size of the Faraday rotator 75 (particularly, the length along the light traveling direction) is shown enlarged.

[0067] First, as shown in Fig. 2, light emitted from the image generating unit 24 is reflected by the plane mirror 26 and the concave mirror 27 and enters the first polarizing plate 71 of the optical isolator 70. Then, as shown in Fig. 5, the first polarizing plate 71 transmits light having only a specific vibration direction component out of the light L1a emitted from the image generating unit 24 and emits it toward the Faraday element 73. Specifically, when the unpolarized light emitted from the image generating unit 24 passes through the first polarizing plate 71, the first polarizing plate 71 absorbs, for example, the horizontal component of the electric field. As a result, the light L1b after passing through the first polarizing plate 71 becomes linearly polarized light having only a vertical component.

[0068] Next, the light L1b (linearly polarized light having only a vertical component) emitted from the first polarizer 71 is incident on the Faraday element 73 (the Faraday rotator 75 thereof). As described in FIG. 4, the magnetic field lines F passing through the Faraday rotator 75 are aligned along the direction D from the first polarizer 71 to the second polarizer 72. That is, the traveling direction of the light L1b incident on the Faraday rotator coincides with the direction of the magnetic field (magnetic field) applied to the Faraday rotator 75. Therefore, due to the Faraday effect of the Faraday layer 75B, the light L1b, which is linearly polarized light having only a vertical component, is emitted from the Faraday rotator 75 as light L1c rotated, for example, by 45° clockwise.

[0069] Next, light L1c, whose polarization plane has been rotated 45 degrees clockwise by the Faraday rotator 75, is incident on the second polarizing plate 72. The second polarizing plate 72 is disposed so that it can transmit light L1c whose polarization direction has been rotated 45 degrees clockwise. In other words, the light that can transmit through the second polarizing plate 72 is light that has been rotated 45 degrees clockwise with respect to the light that has only a vertical component that has been transmitted through the first polarizing plate 71. Therefore, light L1c that has been rotated 45 degrees clockwise by the Faraday rotator 75 passes through the second polarizing plate 72 as is and is irradiated onto the windshield 18.

[0070] Returning to FIG. 2 , a portion of the light that is transmitted through the Faraday element 73 (first polarizing plate 71, Faraday element 73, and second polarizing plate 72) and irradiated onto the windshield 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 (an example of a predetermined image) formed at a predetermined distance in front of the windshield 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 windshield 18, and as a result, the occupant can visually recognize the virtual image object I formed by the virtual image (image) as floating above the road located outside the vehicle.

[0071] 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.

[0072] 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 distance that is arbitrarily determined. When forming a 3D image (stereoscopic image) 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. In addition, 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 optical distance (optical path length) from the image generation unit 24 to the occupant's viewpoint E (for example, by adjusting the distance between the image generation unit 24 and the concave mirror 27).

[0073] 6, when light L2a traveling in the opposite direction to the light emitted from the image generation unit 24 (hereinafter referred to as returned light) enters the second polarizing plate 72 of the optical isolator 70, light L2b, which has only a specific directional component, of the returned light L2a, passes through the second polarizing plate 72 and is emitted. As described above, the light L2b that can pass through the second polarizing plate 72 is light that is rotated 45° clockwise as viewed from the first polarizing plate 71 and Faraday element 73 side, relative to the light that has only a vertical component that passes through the first polarizing plate 71 (i.e., light that is rotated 45° counterclockwise as viewed from the traveling direction of the returned light L2a).

[0074] Next, the returned light L2b that is emitted from the second polarizing plate 72 and enters the Faraday rotator 75 rotates in the direction opposite to the rotation direction of the light L1b that is emitted from the image generating unit 24. That is, the returned light L2b that is incident on the Faraday rotator 75 is rotated 45° counterclockwise with respect to the traveling direction of the returned light L2b. Therefore, the returned light L2c that is emitted from the Faraday rotator 75 becomes light that has only a horizontal component that is rotated 90° relative to the light L1b that is emitted from the image generating unit 24 and transmitted through the first polarizing plate 71 and has only a vertical component.

[0075] Next, the returned light L2c having only a horizontal component output from the Faraday rotator 75 is incident on the first polarizing plate 71. However, the returned light L2c is absorbed by the first polarizing plate 71 and does not pass through the first polarizing plate 71. This is because, as described above, the returned light L2c incident on the first polarizing plate 71 is linearly polarized light having only a horizontal component rotated 90° with respect to the polarization direction of light that can pass through the first polarizing plate 71, that is, the light L2c having only a vertical component output from the image generating unit 24 and passed through the first polarizing plate 71.

[0076] 7, in the case of a HUD 20A that does not have an optical isolator 70 like that shown in FIG. 2, when external light such as sunlight coming from outside the vehicle enters the housing 22 through the exit window 23, the external light may be reflected by the concave mirror 27 or the plane mirror 26 and concentrated before being irradiated onto the image generation unit 24. When such concentrated external light is irradiated onto (the light exit surface of) the image generation unit 24, far infrared rays contained in the external light may cause an excessive temperature rise on the light exit surface, resulting in heat damage and deterioration of the image generation unit 24.

[0077] In contrast, the HUD 20 according to this embodiment includes an image generation unit 24 (an example of a light source), a concave mirror 27 (an example of an optical element) that transmits or reflects light emitted from the image generation unit 24 to magnify the light and irradiate it to the outside, and an optical isolator 70 that can transmit the light emitted from the image generation unit 24 while preventing external light from outside the vehicle from entering the image generation unit 24. The optical isolator 70 is disposed in the HUD 20 between the concave mirror 27 and the windshield 18 at a position through which the light emitted from the image generation unit 24 passes. As a result, as shown in FIG. 8, the optical isolator 70 can prevent external light from entering the image generation unit 24. This prevents heat damage. Furthermore, as shown in FIG. 5, the optical isolator 70 can transmit the light emitted from the image generation unit 24, so the image generation function (light emission function) is not impaired.

[0078] The optical isolator 70 in this embodiment includes a first polarizing plate 71 that polarizes light L1a emitted from the image generating unit 24, for example, in the vertical direction (an example of a first direction), a Faraday element 73 that rotates light L1b polarized by the first polarizing plate 71 by 45° clockwise as viewed from the traveling direction of light L1b from the vertical direction (an example of a second direction) by the Faraday effect generated in response to the application of a magnetic field, and emits the light L1c, and a second polarizing plate 72 that transmits the light L1c rotated by the Faraday element 73. The Faraday element 73 is configured to transmit returning light L2b, which is returned light (e.g., external light) in the opposite direction to the traveling direction of light L1a emitted from the image generating unit 24 and is polarized by the second polarizing plate 72, while rotating the returned light L2b by 45° counterclockwise as viewed from the traveling direction, and then emits the returned light along the horizontal direction (an example of a third direction). Return light L2c, which has only a horizontal component, is blocked by the first polarizing plate 71 and does not reach the image generation unit 24. In this way, with a simple configuration, it is possible to block external light entering the image generation unit 24 and prevent heat damage.

[0079] The Faraday element 73 (Faraday rotator 75) includes a base layer 75A, a Faraday layer 75B provided on the base layer 75A, and a protective layer 75C provided on the Faraday layer 75B. This makes it possible to suppress deterioration of the Faraday rotator 75.

[0080] As described above, at least one of the first polarizing plate 71 and the second polarizing plate 72 may be provided with a filter for blocking at least one of ultraviolet light and infrared light, thereby broadening the bandwidth required for the Faraday element 73, i.e., reducing the wavelength dependency of the Faraday element 73.

[0081] (First Modification) FIG. 9 is a schematic diagram showing the configuration of a HUD 20B according to a first modified example of the first embodiment. The HUD 20B shown in FIG. 9 differs from the HUD 20 of the first embodiment, in that the optical isolator 70 is disposed between the image generation unit 24 and the plane mirror 26. Thus, disposing the optical isolator 170 between the image generation unit 24 and the plane mirror 26 can also block external light from entering the image generation unit 24 without impairing the light output function of the image generation unit 24. In this modification, the first polarizing plate 171 and the second polarizing plate 172 of the optical isolator 170 are preferably configured as reflective polarizers rather than absorptive polarizers. The use of reflective polarizers can suppress heat buildup within the HUD main body 21. Compared to the optical isolator 70 of the first embodiment, the optical isolator 170 is disposed closer to the image generation unit 24 (i.e., closer to the center of the HUD main body 21). Therefore, even if reflective polarizers are used for the first polarizing plate 171 and the second polarizing plate 172, there is little possibility that glare will occur.

[0082] (Second Modification) FIG. 10 is a schematic diagram showing the configuration of a HUD 20C according to a second modified example of the first embodiment. As shown in FIG. 10 , a HUD 20C according to the modified example includes a HUD main body 21 and a combiner 19. The combiner 19 is a separate structure from the windshield 18 and is provided inside the windshield 18. The combiner 19 is, for example, a transparent plastic disk, and light reflected by a plane mirror 26 and a concave mirror 27 and transmitted through an optical isolator 70 is irradiated onto the combiner 19 instead of the windshield 18. As a result, a portion of the light irradiated from the HUD main body 21 onto the combiner 19 is reflected toward the occupant's viewpoint E, similar to the case where light is irradiated onto the windshield 18. As a result, the occupant can recognize the light (predetermined image) emitted from the HUD main body 21 as a virtual image object I formed at a predetermined distance in front of the combiner 19 (and the windshield 18). The HUD 20C including the combiner 19 in this manner can also achieve the same effects as the HUD 20 of the first embodiment.

[0083] Second Embodiment FIG. 11 is a schematic diagram illustrating a vehicle lamp 300 according to the second embodiment. 11, a vehicle lamp 300 (an example of a light emitting device) includes a lamp housing 301 and a transparent cover 302 (an example of an outer lens) attached to cover the opening of the lamp housing 301. A light source unit 310 is provided together with an extension 304 in a lamp chamber 303 defined by the lamp housing 301 and the transparent cover 302. An electronic unit 305 is attached to the outer bottom surface of the lamp housing 301 as a lighting control unit that controls the lighting state of a light source (LED 312) mounted in the light source unit 310.

[0084] The light source unit 310 is a so-called projector-type lamp unit, and includes a unit base 311 and an LED 312 provided as a light source on the unit base 311. The light source unit 310 further includes a reflector 313 provided to cover the LED 312, an optical isolator 314 arranged in front of the LED 312, and a projection lens 315 arranged in front of the optical isolator 314.

[0085] Although not shown in the figures, the optical isolator 314 has the same configuration as the optical isolator 70 of the first embodiment. That is, the optical isolator 314 includes a first polarizing plate, a second polarizing plate, and a Faraday element. The Faraday element is disposed between the first polarizing plate and the second polarizing plate on the optical path of the light emitted from the LED 312.

[0086] According to the vehicle lamp 300 configured in this manner, the optical isolator 314 is disposed between the LED 312 and the projection lens 315 at a position through which the light emitted from the LED 312 passes. This prevents external light from entering the LED 312, thereby preventing heat damage. Furthermore, the light emitted from the LED 312 can be transmitted through the optical isolator 314 and emitted forward of the vehicle lamp 300 via the projection lens 315 and the transparent cover 302. Therefore, the light emission function of the LED 312 is not impaired.

[0087] (Third embodiment) FIG. 12 is a schematic diagram of a HUD 120 according to the third embodiment, as viewed from the side of the vehicle 1. In the description of the third embodiment, for convenience, descriptions of components having the same reference numbers as components already described in the description of the first embodiment will be omitted. As illustrated in FIG. 12, the HUD 120 includes a HUD main body 21. The HUD main body 21 has a housing 22 and an exit window 23. The HUD main body 21 has an image generation unit 24, a control unit 25, and a concave mirror 30 (an example of a reflecting unit) inside the housing 22.

[0088] The image generator 24 is configured to emit light for generating a predetermined image for displaying HUD information. The predetermined image includes a first image for displaying first HUD information and a second image for displaying second HUD information. That is, the image generator 24 is configured to emit first light for generating the first image and second light for generating the second image.

[0089] The concave mirror 30 is disposed on the optical path of the light emitted from the display device of the image generation unit 24. The concave mirror 30 reflects the light emitted from the image generation unit 24 toward the windshield 18 (for example, the front window of the vehicle 1). The concave mirror 30 has a reflective surface 31 that is curved concavely to form a virtual image, and reflects the light image emitted from the image generation unit 24 and formed at a predetermined magnification.

[0090] The reflective surface 31 includes a first reflective area 31A and a second reflective area 31B. The first reflective area 31A reflects first light emitted from the image generation unit 24 for generating a first image. The second reflective area 31B reflects second light emitted from the image generation unit 24 for generating a second image. The image generation unit 24 includes a first image area onto which the first light is irradiated onto the first reflective area 31A, and a second image area onto which the second light is irradiated onto the second reflective area 31B. The control unit 25 controls the image generation operation of the image generation unit 24 for the first image area and the second image area so that the first light is irradiated onto the first reflective area 31A and the second light is irradiated onto the second reflective area 31B.

[0091] The light reflected by the concave mirror 30 and emitted from the exit window 23 of the HUD main body 21 is irradiated onto the windshield 18. A portion of the light irradiated from the HUD main body 21 onto the windshield 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 (an example of a predetermined image) formed at a predetermined distance in front of the windshield 18. In this way, the predetermined image displayed by the HUD 20 is superimposed on the real space in front of the vehicle 1 through the windshield 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.

[0092] The second reflection area 31B of the reflection surface 31 of the concave mirror 30 has a second surface roughness that is rougher than the first surface roughness of the first reflection area 31A. As a result, in the virtual image object I, the virtual image of the first image formed by the light reflected by the first reflection area 31A is recognized as a virtual image having higher image quality than the virtual image of the second image formed by the light reflected by the second reflection area 31B.

[0093] Next, the specific configuration of a concave mirror 30 according to a third embodiment will be described with reference to FIGS. 13A to 13C. FIG. 13A is a schematic diagram of a concave mirror 30 according to a third embodiment as viewed from the image generation unit 24. In FIG. 13A, the dashed line indicates the boundary between the first reflection region 31A and the second reflection region 31B. FIG. 13B is a cross-sectional view of the concave mirror 30 of FIG. 13A taken along line IIIB-IIIB and viewed from the direction of the arrow. FIG. 13C is a partially enlarged view of region IIIC in FIG. 13B. In FIG. 13C, the two-dot chain line indicates the boundary between regions 41a and 42a on the rear surface 40a of the base member 40 and regions 51a and 52a on the rear surface 50a of the reflective film 50, which correspond to the first reflection region 31A and the second reflection region 31B.

[0094] As illustrated in FIG. 13A, the concave mirror 30 is formed so that the first reflection area 31A and the second reflection area 31B are arranged side by side in the vertical direction of the vehicle.

[0095] The concave mirror 30 has a base member 40 and a reflective film 50 formed on the base member 40, for example, as illustrated in FIG. 13B.

[0096] The base member 40 is formed, for example, from a thermoplastic resin such as polycarbonate, glass, or the like. The rear surface 40a of the base member 40 (the surface on which the reflective film 50 is formed) is formed so that regions corresponding to the first reflective region 31A and the second reflective region 31B have different surface roughnesses. Specifically, as illustrated in FIG. 13C , the rear surface 40a of the base member 40 has a region 41a corresponding to the first reflective region 31A and a region 42a corresponding to the second reflective region 31B. The rear surface 40a is formed so that the surface roughness of the region 41a is smoother than the surface roughness of the region 42a. For example, the base member 40 may be formed by injection molding a thermoplastic resin using a mold formed so that the surface roughness of the region 41a of the rear surface 40a is smoother than the surface roughness of the region 42a.

[0097] The reflective film 50 is formed of a metal such as aluminum. The reflective film 50 is formed so that the rear surface 50a has different surface roughnesses in regions corresponding to the first reflective region 31A and the second reflective region 31B. Specifically, as illustrated in FIG. 13C , the rear surface 50a of the reflective film 50 has a region 51a that forms the first reflective region 31A and a region 52a that forms the second reflective region 31B. The rear surface 50a is formed so that the surface roughness of the region 51a is smoother than the surface roughness of the region 52a. Here, the rear surface 50a of the reflective film 50 forms the reflective surface 31 that reflects light emitted from the image generation unit 24. Therefore, the surface roughness of the region 52a, i.e., the surface roughness of the second reflective region 31B, is rougher than the surface roughness of the region 51a, i.e., the surface roughness of the first reflective region 31A. For example, the reflective film 50 may be formed by vapor-depositing a metal such as aluminum on the base member 40. The reflective film 50 formed by vapor deposition is thin and is affected by the surface roughness of the rear surface 40a of the base member 40, so that the rear surface 50a can be formed with different surface roughness between the regions 51a and 52a.

[0098] 14 is a schematic diagram illustrating an area 60 of the windshield 18 that is irradiated with light emitted from the HUD 120. In FIG. 14, a dashed dotted line C indicates a center line that passes through the vertical center of the windshield 18 and extends horizontally.

[0099] 14, when light emitted from the HUD 120 is irradiated onto an area 60 on the windshield 18 that is located below the center line C, the concave mirror 30 is formed so that the first reflective area 31A is located below the second reflective area 31B, for example, as illustrated in FIG. 13A. As a result, as illustrated in FIG. 14, the first light reflected by the first reflective area 31A is irradiated onto the area 60A on the windshield 18. Furthermore, the second light reflected by the second reflective area 31B is irradiated onto the area 60B on the windshield 18 that is located below the area 60A.

[0100] As described above, the HUD 120 according to the third embodiment includes an image generator 24 that emits first light for generating a first image among predetermined images and second light for generating a second image among predetermined images. The HUD 120 also includes a concave mirror 30 that serves as a reflector that reflects the first light and the second light emitted by the image generator 24 so that the first light and the second light are irradiated onto the windshield 18. The concave mirror 30 has a reflective surface 31 that includes a first reflective region 31A that reflects the first light and a second reflective region 31B that reflects the second light. The first reflective region 31A has a first surface roughness, and the second reflective region 31B has a second surface roughness that is rougher than the first surface roughness. With this configuration, the second reflective region 31B has a rougher surface roughness than the first reflective region 31A, and therefore can be formed at a lower cost than the first reflective region 31A. Meanwhile, the first reflective region 31A has a smoother surface roughness than the second reflective region 31B, and therefore the first image is perceived as a high-quality virtual image. Therefore, a concave mirror can be realized at low cost without significantly degrading the image quality of the virtual image.

[0101] The concave mirror 30 also has a base member 40 and a reflective film 50 formed on the base member 40. The rear surface 50a of the reflective film 50 forms the reflective surface 31. The surface roughness of the base member 40 (region 42a of the rear surface 40a) corresponding to the second reflective region 31B is rougher than the surface roughness of the base member 40 (region 41a of the rear surface 40a) corresponding to the first reflective region 31A. The surface roughness of the reflective film 50 (rear surface 50a) varies depending on the reflective region due to the influence of the surface roughness of the base member 40. With this configuration, by changing the surface roughness of the base member 40 depending on the reflective region, it is possible to easily form a reflective film 50 having different surface roughness depending on the reflective region.

[0102] As illustrated in FIG. 14 , the first light reflected by the first reflective region 31A is irradiated onto a region 60A above a region 60B of the windshield 18 onto which the second light reflected by the second reflective region 31B is irradiated. That is, the first reflective region 31A and the second reflective region 31B are arranged side by side in the vertical direction of the vehicle so that the first light for generating the first image is irradiated onto a position on the windshield 18 closer to the vertical center of the windshield 18 than the second light for generating the second image. This configuration allows the driver to perceive the virtual image of the first image closer to the vertical center of the windshield 18 than the virtual image of the second image. While the vehicle is traveling, the driver is likely to direct their gaze toward a region closer to the vertical center of the windshield 18. Therefore, the driver can perceive a high-quality virtual image of the first image without significantly moving their gaze while the vehicle is traveling. This allows the driver to accurately grasp the information displayed by the first image. Furthermore, the driver can perceive the virtual image of the second image simply by moving their gaze vertically away from the virtual image of the first image.

[0103] For example, the first image may show important information regarding vehicle travel, and the second image may show incidental information. Important information regarding vehicle travel may be, for example, vehicle travel information or information about an object outside the vehicle. Incidental information may be, for example, information such as a warning. In this case, the driver can accurately grasp the important information through a high-quality virtual image. Furthermore, the driver can check the incidental information simply by moving their gaze up or down as needed. By representing the incidental information using, for example, an image of a large mark or symbol that is less affected by image quality, the driver can check both the important information and the incidental information without feeling uncomfortable. Therefore, compared to a concave mirror configured with a smooth surface roughness throughout, a low-cost concave mirror can be provided that provides almost the same information transmission function.

[0104] (Variation) In the third embodiment, the surface roughness of the base member 40 is changed depending on the reflection area, thereby forming a concave mirror 30 whose reflection surface 31 has different surface roughness depending on the reflection area. However, this is not limited to this. Fig. 15A is a schematic diagram illustrating a concave mirror 130 according to a modification of the third embodiment. Fig. 15B is a cross-sectional view of the concave mirror 130 taken along line VB-VB and viewed from the direction of the arrows.

[0105] The modified concave mirror 130 has a reflecting surface 131 facing the image generating unit 24. As illustrated in Fig. 15A, the reflecting surface 131 is formed to include a first reflecting region 131A having a first surface roughness and a second reflecting region 131B having a second surface roughness that is rougher than the first surface roughness.

[0106] As illustrated in FIG. 15B , the concave mirror 130 includes a base member 140 and a reflective film 150 formed on the base member 140. The base member 140 includes a first base member 141 and a second base member 142. The reflective film 150 includes a first reflective film 151 formed on the first base member 141 and a second reflective film 152 formed on the second base member 142. The first reflective film 151 and the second reflective film 152 are formed of a metal such as aluminum. For example, the first reflective film 151 is formed by evaporating a metal such as aluminum onto the first base member 141. The second reflective film 152 is formed by evaporating a metal such as aluminum onto the second base member 142. The rear surface of the reflective film 150 forms a reflective surface 131 that reflects light emitted from the image generation unit 24. Therefore, the rear surface 151a of the first reflective film 151 forms a first reflective region 131A. The rear surface 152a of the second reflective film 152 forms the second reflective region 131B.

[0107] The first base member 141 and the second base member 142 are formed from different materials so that the second reflective region 131B has a second surface roughness that is rougher than the first surface roughness of the first reflective region 131A. For example, the first base member 141 is formed from glass, and the second base member 142 is formed from a thermoplastic resin such as polycarbonate. The surface of glass can be processed with higher precision than that of thermoplastic resin. Therefore, the surface roughness of the rear surface 142a of the second base member 142, which is formed from a thermoplastic resin, is formed to be rougher than the surface roughness of the rear surface 141a of the first base member 141, which is formed from high-precision glass. The surface roughness of the rear surfaces 151a and 152a of the reflective film 150 changes due to the influence of the surfaces of the rear surfaces 141a and 142a of the base member 140. Therefore, the surface roughness of the rear surface 152a, ie, the surface roughness of the second reflective area 131B, is greater than the surface roughness of the rear surface 151a, ie, the surface roughness of the first reflective area 131A.

[0108] As described above, the modified concave mirror 130 has a first base member 141 and a second base member 142 formed from different materials. The surface roughness of the reflective film 150 varies depending on the reflective area, influenced by the surface of the base member 140. With this configuration, by changing the material of the base member 140 depending on the reflective area, it is possible to easily form a reflective film 150 having different surface roughness depending on the reflective area.

[0109] Furthermore, the surface roughness of the concave mirror 130 may be adjusted so that the first base member 141 and the second base member 142 each have a desired surface roughness, like the concave mirror 30 of the third embodiment.

[0110] (Fourth embodiment) Next, the specific configuration of concave mirror 230 according to the fourth embodiment will be described with reference to Figures 16A and 16B. Figure 16A is a schematic diagram of concave mirror 230 according to the fourth embodiment as viewed from image generation unit 24. Figure 16B is a cross-sectional view of concave mirror 230 in Figure 16A as viewed from the direction of the arrows along line VIB-VIB. In Figure 16A, dashed lines indicate boundaries between first reflection region 231A, second reflection region 231B, and third reflection region 231C.

[0111] The image generator 24 of the fourth embodiment is configured to emit light for generating predetermined images including a first image, a second image, and a third image for displaying HUD information. That is, the image generator 24 is configured to emit first light for generating the first image, second light for generating the second image, and third light for generating the third image.

[0112] The concave mirror 230 has a reflecting surface 231 facing the image generating unit 24. As illustrated in FIG. 16A , the reflecting surface 231 is formed to include a first reflecting area 231A, a second reflecting area 231B, and a third reflecting area 231C that are arranged side by side in the horizontal direction of the vehicle. The first reflecting area 231A is configured to reflect the first light emitted from the image generating unit 24. The second reflecting area 231B is configured to reflect the second light emitted from the image generating unit 24. The third reflecting area 231C is configured to reflect the third light emitted from the image generating unit 24. The control unit 25 controls the operation of the image generating unit 24 so that the first light, the second light, and the third light are irradiated onto the first reflecting area 231A, the second reflecting area 231B, and the third reflecting area 231C.

[0113] The first reflection region 231A, the second reflection region 231B, and the third reflection region 231C are formed to have different surface roughnesses. Specifically, the second reflection region 231B has a second surface roughness that is rougher than the first surface roughness of the first reflection region 231A. The third reflection region 231C has a third surface roughness that is rougher than the first surface roughness of the first reflection region 231A. That is, the virtual image of the first image formed by the light reflected by the first reflection region 231A is recognized as a virtual image having higher image quality than the virtual image of the second image formed by the light reflected by the second reflection region 231B. The virtual image of the first image formed by the light reflected by the first reflection region 231A is recognized as a virtual image having higher image quality than the virtual image of the third image formed by the light reflected by the third reflection region 231C.

[0114] As illustrated in FIG. 16B , the concave mirror 230 has a base member 240 and a reflective film 250 formed on the base member 240. The base member 240 is formed from, for example, a thermoplastic resin such as polycarbonate, glass, or the like. The reflective film 250 is formed from, for example, a metal such as aluminum. As in the third embodiment and its modified example, the surface roughness of the first reflective region 231A, the second reflective region 231B, and the third reflective region 231C are made different by varying the surface roughness and / or material of the base member 240.

[0115] 17 is a schematic diagram illustrating an example of an area 160 on the windshield 18 onto which light emitted from the HUD 120 is irradiated. As illustrated in FIG. 17, when light emitted from the HUD 120 is irradiated onto area 160 on the windshield 18, the concave mirror 230 is formed such that the second reflective area 231B is located to the left of the first reflective area 231A and the third reflective area 231C is located to the right of the first reflective area 231A along the horizontal direction of the vehicle, as illustrated in FIG. 16A. As a result, the first light for generating the first image reflected by the first reflective area 231A is irradiated onto area 160A. The second light for generating the second image reflected by the second reflective area 231B is irradiated onto area 160B located to the left of area 160A in the horizontal direction of the windshield 18. The third light for generating the third image reflected by the third reflection area 231C is irradiated onto an area 160C located to the right of the area 160A in the horizontal direction of the windshield 18.

[0116] Thus, the reflective surface 231 of the concave mirror 230 according to the fourth embodiment further includes a third reflective region 231C that reflects third light to generate a third image among the predetermined images. The third reflective region 231C has a third surface roughness that is coarser than the first surface roughness of the first reflective region 231A. The first reflective region 231A, the second reflective region 231B, and the third reflective region 231C are arranged horizontally on the vehicle, with the first reflective region 131A sandwiched between the second reflective region 231B and the third reflective region 231C. This configuration allows the driver to recognize virtual images of each image while the vehicle is traveling simply by moving their gaze left and right. For example, the first image may display important information regarding the vehicle's travel, and the second and third images may display additional information. In this case, the driver can accurately grasp the important information through high-quality virtual images. Furthermore, once the driver has grasped important information regarding the vehicle's travel, they can check the additional information simply by moving their gaze left and right as needed. Therefore, compared to a case where the entire concave mirror is configured to have smooth surface roughness, it is possible to provide a low-cost concave mirror that has almost the same information transmission function.

[0117] The concave mirror 230 may be formed of only two reflective areas, a first reflective area 231A and a second reflective area 231B, arranged side by side in the horizontal direction. For example, the first reflective area 231A and the second reflective area 231B are arranged so that the virtual image of the first image is recognized at a position in the horizontal direction of the windshield 18 that the driver frequently looks at. With this configuration, the driver can recognize a high-quality virtual image of the first image without moving their line of sight much while driving the vehicle. This allows the driver to accurately grasp the information displayed by the first image. Furthermore, the driver can recognize the virtual image of the second image by simply moving their line of sight left or right from the virtual image of the first image.

[0118] Fifth Embodiment FIG. 18 is a schematic diagram of the HUD 220 as seen from the side of the vehicle 1. In the description of the fifth embodiment, for convenience, descriptions of components having the same reference numbers as components already described in the description of the first embodiment will be omitted. As illustrated in FIG. 18, the HUD 220 includes a HUD main body 21. The HUD main body 21 has a housing 22 and an exit window 23. The HUD main body 21 has an image generation unit 24, a control unit 25, and a reflection unit 126 inside the housing 22.

[0119] The image generation unit 24 is configured to emit light for generating a predetermined image to be displayed toward an occupant of the vehicle 1. The predetermined image includes a first image for displaying first HUD information and a second image for displaying second HUD information. The image generation unit 24 is configured to emit the first light for generating the first image and the second light for generating the second image.

[0120] The reflecting unit 126 is disposed on the optical path of the light emitted from the display device of the image generating unit 24. The reflecting unit 126 reflects the light emitted from the image generating unit 24 toward the windshield 18 (for example, the front window of the vehicle 1).

[0121] The light reflected by the reflector 126 and emitted from the exit window 23 of the HUD main body 21 is irradiated onto the windshield 18. A portion of the light irradiated from the HUD main body 21 onto the windshield 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 (an example of a predetermined image) formed at a predetermined distance in front of the windshield 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 windshield 18, and as a result, the occupant can visually recognize the virtual image objects Ia and Ib formed by the virtual image (image) as floating above the road located outside the vehicle.

[0122] The reflecting unit 126 has a concave mirror 126A and a plane mirror 126B. The concave mirror 126A has a concavely curved reflecting surface to form a virtual image, and reflects the light image emitted from the image generating unit 24 and formed at a predetermined magnification. The plane mirror 126B has a planar reflecting surface to form a virtual image, and reflects the light image emitted from the image generating unit 24 and formed at the same magnification. As illustrated in FIG. 19 , the concave mirror 126A and the plane mirror 126B are arranged side by side in the vertical direction of the vehicle 1, with the concave mirror 126A positioned lower than the plane mirror 126B. The image generating unit 24 includes a first image area into which the first light irradiated onto the concave mirror 126A is emitted, and a second image area into which the second light irradiated onto the plane mirror 126B is emitted. The control unit 25 controls the image generation operation of the image generation unit 24 for the first image region and the second image region so that the first light is irradiated onto the concave mirror 126A and the second light is irradiated onto the plane mirror 126B.

[0123] For example, light (an example of a first light) emitted from point Pa1 on the light emission surface 24A of the image generation unit 24 travels along optical path La1, is reflected at point Pa2 on the concave mirror 126A, travels along optical path La2, and is emitted to the outside of the HUD 220 through the exit window 23 of the HUD main body 21. The light that has traveled along optical path La2 is incident on point Pa3 on the windshield 18, thereby forming part of a virtual image object Ia (an example of a first image) formed by a predetermined image. The virtual image object Ia is formed forward, a relatively long predetermined distance (for example, approximately 7 to 10 meters) away from the windshield 18.

[0124] On the other hand, light (an example of second light) emitted from point Pb1 on the light emission surface 24A of the image generation unit 24 travels along optical path Lb1, is reflected at point Pb2 on the plane mirror 126B, travels along optical path Lb2, and is emitted to the outside of the HUD 220 through the exit window 23 of the HUD main body 21. The light that has traveled along optical path Lb2 is incident on point Pb3 on the windshield 18, thereby forming part of a virtual image object Ib (an example of a second image) formed by a predetermined image. The virtual image object Ib is formed, for example, forward and away from the windshield 18 by a shorter distance (for example, about 3 to 5 m) than the virtual image object Ia.

[0125] 20 is a schematic diagram illustrating an area 260 of the windshield 18 that is irradiated with light emitted from the HUD 220. In FIG. 20, a dashed dotted line C indicates a center line that passes through the vertical center of the windshield 18 and extends horizontally.

[0126] 20 , the light emitted from the HUD 220 is irradiated onto an area 260 on the windshield 18 that is located below the center line C. The first light reflected by the concave mirror 126A is irradiated onto an area 260A on the windshield 18. The second light reflected by the plane mirror 126B is irradiated onto an area 260B on the windshield 18. That is, the first light reflected by the concave mirror 126A is irradiated onto a position on the windshield 18 closer to the vertical center of the windshield 18 than the second light reflected by the plane mirror 126B. As a result, the virtual image object Ia is formed at a position closer to the vertical center of the windshield 18 than the virtual image object Ib.

[0127] When forming 2D images (planar images) as the virtual image objects Ia and Ib, a predetermined image is projected to become a virtual image at a single distance that is arbitrarily determined. When forming 3D images (stereoscopic images) as the virtual image objects Ia and Ib, 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 objects Ia and Ib (the distance from the occupant's viewpoint E to the virtual image) can be appropriately adjusted by adjusting the optical distance (optical path length) from the image generation unit 24 to the occupant's viewpoint E (for example, by adjusting the distance between the image generation unit 24 and the reflector 126).

[0128] As described above, the HUD 220 according to the fifth embodiment includes an image generator 24 that emits a first light for generating a first image among predetermined images and a second light for generating a second image among predetermined images. The HUD 220 also includes a reflector 126 that reflects the first light and the second light emitted by the image generator 24 so that the first light and the second light are irradiated onto the windshield 18. The reflector 126 includes a concave mirror 126A that reflects the first light and a plane mirror 126B that reflects the second light. The concave mirror 126A requires a curved, highly precise reflective surface, which requires advanced manufacturing techniques and therefore high manufacturing costs. However, the plane mirror 126B can be manufactured relatively inexpensively, resulting in low costs. Therefore, according to the above configuration, the reflector 126 is configured with the concave mirror 126A and the plane mirror 126B, thereby realizing a low-cost reflector.

[0129] Furthermore, the concave mirror 126A and the plane mirror 126B are arranged side by side in the vertical direction of the vehicle so that the first light is irradiated onto a position on the windshield 18 closer to the vertical center of the windshield 18 than the second light. This configuration allows the driver to perceive the virtual image of the first image closer to the vertical center of the windshield 18 than the virtual image of the second image. While the vehicle is traveling, the driver is likely to direct his or her gaze toward an area closer to the vertical center of the windshield 18. Furthermore, the virtual image of the first image formed by the first light reflected by the concave mirror 126A is farther from the driver's eye position (viewpoint) than the virtual image of the second image formed by the second light reflected by the plane mirror 126B. Therefore, while the vehicle is traveling, the driver can perceive the virtual image of the first image without significantly moving his or her line of sight or shifting the focus of his or her eyes. This allows the driver to instantly grasp the information displayed by the first image. Furthermore, the driver can perceive the virtual image of the second image simply by moving his or her gaze vertically from the virtual image of the first image.

[0130] For example, the first image may show important information regarding vehicle travel, and the second image may show accompanying information. Important information regarding vehicle travel may be, for example, vehicle travel information or information about an object outside the vehicle. The accompanying information may be, for example, information such as a warning. In this case, the driver can instantly grasp important information while the vehicle is traveling without moving his or her eyes much and without shifting the focus of his or her eyes much. Furthermore, the driver can check the accompanying information by simply moving his or her eyes up or down as necessary.

[0131] 20 illustrates a case in which the light emitted from the HUD 220 is irradiated onto the region 260 of the windshield 18 that is located below the center line C, but this is not limiting. The light emitted from the HUD 220 may also be irradiated onto a region of the windshield 18 that is located above the center line C. In this case, the concave mirror 126A and the plane mirror 126B may be arranged side by side in the vertical direction of the vehicle 1 such that the concave mirror 126A is located above the plane mirror 126B. As a result, the first light reflected by the concave mirror 126A is irradiated onto a position closer to the vertical center of the windshield 18 than the second light reflected by the plane mirror 126B on the windshield 18. As a result, the virtual image object Ia is formed at a position closer to the vertical center of the windshield 18 than the virtual image object Ib.

[0132] (Sixth embodiment) FIG. 21 is a schematic diagram of the HUD 220A as viewed from the side of the vehicle 1. As illustrated in FIG. 21, the HUD 220A of the sixth embodiment differs from the HUD 220 of the fifth embodiment in that a lens 28 is disposed between the image generator 24 and the plane mirror 126B.

[0133] Lens 28 is configured to change the focal length of light emitted from light exit surface 24A of image generator 24. Lens 28 is provided at a position through which light emitted from light exit surface 24A of image generator 24 and directed toward plane mirror 126B passes. Lens 28 may be configured to include, for example, a drive unit, and to be able to change the distance from image generator 24 in response to a control signal generated by control unit 25. Movement of lens 28 changes the focal length (apparent optical path length) of the light emitted from image generator 24, thereby changing the distance between windshield 18 and a predetermined image displayed by HUD 220A.

[0134] For example, light emitted from point Pa1 on the light exit surface 24A of the image generation unit 24 travels along optical path La1, is reflected at point Pa2 on the concave mirror 126A, travels along optical path La2, and is emitted to the outside of the HUD 220A through the exit window 23 of the HUD main body 21. The light that has traveled along optical path La2 is incident on point Pa3 on the windshield 18, thereby forming part of a virtual image object Ia formed by a predetermined image.

[0135] On the other hand, light emitted from point Pb1 on the light exit surface 24A of the image generator 24 travels along optical path 1Lb1 after passing through the lens 28. The focal length of the light emitted from point Pb1 changes as it passes through the lens 28. That is, the apparent optical path length of the light emitted from point Pb1 is lengthened as it passes through the lens 28. The light that has traveled along optical path 1Lb1 is reflected by point 1Pb2 on the plane mirror 126B, travels along optical path 1Lb2, and is emitted to the outside of the HUD 220A through the exit window 23 of the HUD main body 21. The light that has traveled along optical path 1Lb2 is incident on point 1Pb3 on the windshield 18, thereby forming part of a virtual image object 1Ib formed by a predetermined image. The virtual image object 1Ib is formed, for example, forward and away from the windshield 18 by a longer distance (for example, approximately 6 to 9 m) than the virtual image object Ib of the fifth embodiment. The distance of the virtual image object Ib (the distance from the windshield 18 to the virtual image) can be adjusted appropriately by adjusting the position of the lens .

[0136] As described above, the HUD 220A according to the sixth embodiment includes a lens 28 disposed on the optical path between the image generator 24 and the plane mirror 126B of the reflector 126. The lens 28 is configured to increase the optical path length from the image generator 24 to the plane mirror 126B. The virtual image of the first image formed by the first light reflected by the concave mirror 126A is located at a greater distance from the driver's eyes than the virtual image of the second image formed by the second light reflected by the plane mirror 126B. This difference in the distance of the virtual image from the driver's eyes may cause the driver to feel uncomfortable. According to the above configuration, the lens 28 increases the optical path length between the image generator 24 and the plane mirror 126B, thereby increasing the distance from the driver's eyes to the virtual image of the second image. This reduces the driver's discomfort caused by the difference in the distance of the virtual images.

[0137] Seventh Embodiment FIG. 22 is a schematic diagram of the HUD 220B as viewed from the side of the vehicle 1. As illustrated in Figure 22, the HUD 220B of the seventh embodiment differs from the HUD 220 of the fifth embodiment in that the reflecting section 226 includes a concave mirror 226A and two plane mirrors 226B and 226C, in that the reflecting section 226 includes a concave mirror 126A and a plane mirror 126B. Note that the position of the plane mirror 226C in the longitudinal direction of the vehicle 1 is the same as the position of the plane mirror 226B, and therefore it is not shown in Fig. 22 due to overlap with the plane mirror 226B. When viewed from the side of the vehicle 1, the optical paths and virtual image objects, etc. associated with the plane mirror 226C are formed in the same manner as the optical paths and virtual image objects, etc. associated with the plane mirror 226B, and therefore are not shown in the illustration, and only the reference numbers are shown in parentheses.

[0138] The reflecting unit 226 has a concave mirror 226A, a plane mirror 226B, and a plane mirror 226C. The concave mirror 226A has a concavely curved reflecting surface to form a virtual image, and reflects the light image emitted from the image generating unit 224 and formed thereon at a predetermined magnification. The plane mirrors 226B and 226C have planar reflecting surfaces to form virtual images, and reflect the light image emitted from the image generating unit 224 and formed thereon at the same magnification. The concave mirror 226A and the plane mirrors 226B and 226C are arranged side by side in the horizontal direction of the vehicle 1, with the concave mirror 226A sandwiched between the plane mirror 226B and the plane mirror 226C, as illustrated in FIG. 23 .

[0139] Image generation unit 224 includes a first image area onto which the first light is emitted to be irradiated onto concave mirror 226A, a second image area onto which the second light is emitted to be irradiated onto plane mirror 226B, and a third image area onto which the third light is emitted to be irradiated onto plane mirror 226C. Control unit 225 controls the image generation operation of image generation unit 224 for the first image area, the second image area, and the third image area so that the first light is irradiated onto concave mirror 226A, the second light is irradiated onto plane mirror 226B, and the third light is irradiated onto plane mirror 226C.

[0140] For example, light (an example of a first light) emitted from point 2Pa1 on light emission surface 24A of image generation unit 224 travels along optical path 2La1, is reflected at point 2Pa2 on concave mirror 226A, travels along optical path 2La2, and is emitted to the outside of HUD 220B through exit window 23 of HUD main body 21. The light that has traveled along optical path 2La2 is incident on point 2Pa3 on windshield 18, thereby forming part of virtual image object 2Ia (an example of a first image) formed by a predetermined image. Virtual image object 2Ia is formed forward, a relatively long predetermined distance (for example, approximately 7 to 10 meters) away from windshield 18.

[0141] On the other hand, light (an example of second light) emitted from point 2Pb1 on the light emission surface 24A of the image generation unit 224 travels along optical path 2Lb1, is reflected at point 2Pb2 on the plane mirror 226B, travels along optical path 2Lb2, and is emitted to the outside of the HUD 220B through the exit window 23 of the HUD main body 21. The light that has traveled along optical path 2Lb2 is incident on point 2Pb3 on the windshield 18, thereby forming part of a virtual image object 2Ib (an example of a second image) formed by a predetermined image. The virtual image object 2Ib is formed, for example, forward and at a shorter distance (for example, about 3 to 5 m) from the windshield 18 compared to the virtual image object 2Ia.

[0142] Light (an example of third light) emitted from point 2Pc1 on the light emission surface 24A of the image generation unit 224 travels along optical path 2Lc1, is reflected by point 2Pc2 on the plane mirror 226C, travels along optical path 2Lc2, and is emitted to the outside of the HUD 220B through the exit window 23 of the HUD main body 21. The light that has traveled along optical path 2Lc2 is incident on point 2Pc3 on the windshield 18, thereby forming part of a virtual image object 2Ic (an example of a third image) formed by a predetermined image. The virtual image object 2Ic is formed, for example, forward and away from the windshield 18 by approximately the same distance as the virtual image object 2Ib.

[0143] FIG. 24 is a schematic diagram illustrating an area 360 on the windshield 18 that is irradiated with light emitted from the HUD 220B. 24, the first light for generating the first image reflected by the concave mirror 226A is irradiated onto an area 360A. The second light for generating the second image reflected by the plane mirror 226B is irradiated onto an area 360B located to the left of the area 360A in the horizontal direction of the windshield 18. The third light for generating the third image reflected by the plane mirror 226C is irradiated onto an area 360C located to the right of the area 360A in the horizontal direction of the windshield 18. As a result, the virtual image object 2Ia is formed in a state where it is sandwiched between the virtual image objects 2Ib and 2Ic along the horizontal direction of the vehicle 1.

[0144] As described above, in the HUD 220B according to the seventh embodiment, the concave mirror 226A, the plane mirror 226B, and the plane mirror 226C are arranged side by side in the horizontal direction of the vehicle 1, with the concave mirror 226A sandwiched between the plane mirror 226B and the plane mirror 226C. This allows the driver to recognize the virtual image of the first image while the vehicle is traveling without significantly shifting the focus of their eyes. This allows the driver to instantly grasp the information displayed by the first image. Furthermore, while the vehicle is traveling, the driver can grasp the virtual image of the second image and the virtual image of the third image simply by moving their line of sight left and right.

[0145] Eighth Embodiment FIG. 25 is a schematic diagram of the HUD 220C as viewed from the side of the vehicle 1. As illustrated in FIG. 25, the HUD 220C of the eighth embodiment differs from the HUD 220B of the seventh embodiment in that a lens 80 is disposed between the image generator 224 and the plane mirrors 226B and 226C.

[0146] The lens 80 is configured to change the focal length of light emitted from the light exit surface 24A of the image generator 224. The lens 80 is provided at a position through which light emitted from the light exit surface 24A of the image generator 224 and proceeding toward the plane mirrors 226B and 226C passes. The lens 80 has a first lens 81 and a second lens 82. The first lens 81 is disposed between the image generator 224 and the plane mirror 226B. The second lens 82 is disposed between the image generator 224 and the plane mirror 226C. Note that the second lens 82 is not shown in FIG. 25 because it overlaps with the first lens 81, as it is positioned in the longitudinal direction of the vehicle 1 in the same position as the first lens 81.

[0147] Lens 80 may include, for example, a drive unit and be configured so that the distance from image generator 224 can be changed by a control signal generated by controller 225. Movement of lens 80 changes the focal length (apparent optical path length) of the light emitted from image generator 224, and changes the distance between windshield 18 and a predetermined image displayed by HUD 220C.

[0148] For example, light emitted from point 3Pa1 on light exit surface 24A of image generation unit 224 travels along optical path 3La1, is reflected by point 3Pa2 on concave mirror 226A, travels along optical path 3La2, and is emitted to the outside of HUD 220C through exit window 23 of HUD main body 21. Light that has traveled along optical path 3La2 is incident on point 3Pa3 on windshield 18, thereby forming part of virtual image object 3Ia formed by a predetermined image. Virtual image object 3Ia is formed forward, a relatively long predetermined distance (for example, about 7 to 10 meters) away from windshield 18.

[0149] On the other hand, light emitted from point 3Pb1 on the light exit surface 24A of the image generation unit 224 passes through the first lens 81 and then travels along optical path 3Lb1. The focal length of the light emitted from point 3Pb1 changes as it passes through the first lens 81. That is, the apparent optical path length of the light emitted from point 3Pb1 is lengthened as it passes through the first lens 81. The light that has traveled along optical path 3Lb1 is reflected by point 3Pb2 on the plane mirror 226B and then travels along optical path 3Lb2, and is emitted to the outside of the HUD 220C through the exit window 23 of the HUD main body 21. The light that has traveled along optical path 3Lb2 is incident on point 3Pb3 on the windshield 18, thereby forming part of a virtual image object 3Ib formed by a predetermined image. For example, compared to the virtual image object 2Ib of the seventh embodiment, the virtual image object 3Ib is formed in front of and at a longer distance (for example, about 6 to 9 m) from the windshield 18. The distance of the virtual image object 3Ib (the distance from the windshield 18 to the virtual image) can be adjusted appropriately by adjusting the position of the first lens 81.

[0150] Light emitted from point 3Pc1 on the light exit surface 24A of the image generation unit 224 passes through the second lens 82 and then travels along optical path 3Lc1. The focal length of the light emitted from point 3Pc1 changes as it passes through the second lens 82. That is, the apparent optical path length of the light emitted from point 3Pc1 is lengthened as it passes through the second lens 82. The light that has traveled along optical path 3Lc1 is reflected by point 3Pc2 on the plane mirror 226C and then travels along optical path 3Lc2, and is emitted to the outside of the HUD 220C through the exit window 23 of the HUD main body 21. The light that has traveled along optical path 3Lc2 is incident on point 3Pc3 on the windshield 18, thereby forming part of a virtual image object 3Ic formed by a predetermined image. For example, compared to the virtual image object 2Ic of the seventh embodiment, the virtual image object 3Ic is formed in front of and at a longer distance (for example, about 6 to 9 m) from the windshield 18. The distance of the virtual image object 3Ic (the distance from the windshield 18 to the virtual image) can be adjusted appropriately by adjusting the position of the second lens 82.

[0151] As described above, the HUD 220C according to the eighth embodiment includes a first lens 81 disposed on the optical path between the image generator 224 and the plane mirror 226B of the reflector 226. The HUD 220C also includes a second lens 82 disposed on the optical path between the image generator 224 and the plane mirror 226C of the reflector 226. The first lens 81 is configured to increase the optical path length from the image generator 224 to the plane mirror 226B. The second lens 82 is configured to increase the optical path length from the image generator 224 to the plane mirror 226C. The virtual image of the first image formed by the first light reflected by the concave mirror 226A is located at a greater distance from the driver's eyes than the virtual image of the second image formed by the second light reflected by the plane mirror 226B. The virtual image of the first image formed by the first light reflected by the concave mirror 226A is located at a greater distance from the driver's eyes than the virtual image of the third image formed by the third light reflected by the plane mirror 226C. Therefore, the difference in the distance of the virtual image from the driver's eye position may cause the driver to feel uncomfortable. According to the above configuration, the first lens 81 increases the optical path length between the image generator 224 and the plane mirror 226B, thereby increasing the distance from the driver's eye position to the virtual image of the second image. Furthermore, the second lens 82 increases the optical path length between the image generator 224 and the plane mirror 226C, thereby increasing the distance from the driver's eye position to the virtual image of the third image. This reduces the discomfort felt by the driver due to the difference in the distance of the virtual images.

[0152] Ninth embodiment FIG. 26 is a schematic diagram of the HUD 320 as seen from the side of the vehicle 1. In the description of the ninth embodiment, for the sake of convenience, descriptions of components having the same reference numbers as components already described in the description of the first embodiment will be omitted. As shown in FIG. 26, the HUD 320 includes a HUD main body 21. The HUD main body 21 has a housing 22 and an exit window 23. The HUD main body 21 has an image generation unit 24, a control unit 25, and a concave mirror 27 (an example of a reflecting unit) inside the housing 22.

[0153] The image generation unit 24 emits light for generating an image from a light emission surface (display device surface) 124 toward the outside. The light emission surface 124 of the image generation unit 24 is provided with a first light emission surface (an example of a first region) 124A and a second light emission surface (an example of a second region) 124B, which is an emission surface other than the first light emission surface 124A. The first light emission surface 124A is an emission surface that emits light for generating a first image, which is a part of a predetermined image. The second light emission surface 124B is an emission surface that emits light for generating a second image, which is a part of the predetermined image and different from the first image. The first light emission surface 124A and the second light emission surface 124B will be described later with reference to FIG. 28.

[0154] The concave mirror 27 is disposed on the optical path of the light emitted from the image generation unit 24. The concave mirror 27 is configured to reflect the light emitted from the image generation unit 24 toward the windshield 18 (for example, the front window of the vehicle 1). The concave mirror 27 has a reflective surface that is concavely curved to form a predetermined image, and reflects the light image emitted from the image generation unit 24 and formed thereon at a predetermined magnification. The concave mirror 27 may have a drive mechanism (not shown) and be configured to be able to rotate the orientation of the concave mirror 27 based on a control signal transmitted from the control unit 25.

[0155] Light emitted from the light exit surface 124 of the image generation unit 24 is reflected by the concave 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 windshield 18. A portion of the light irradiated from the exit window 23 onto the windshield 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 windshield 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 windshield 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.

[0156] However, since the light emitted from the light exit surface 124 of the image generating unit 24 is reflected by the concave mirror 27, the virtual image object I recognized by the occupant as a predetermined image is distorted due to the reflection from the concave mirror 27. Therefore, in order to allow the occupant to accurately recognize the information about the virtual image object I, it is desirable to correct the distortion of the generated virtual image object I, for example.

[0157] Next, the distortion occurring in the virtual image object and the process for correcting the distortion (correction by image warping) will be described with reference to FIGS. 27A, 27B, 28, and 29. FIG.

[0158] Fig. 27A shows an example of an image generated by light emitted from an image generating unit of a HUD according to a comparative example, that is, an image on a light emission surface 424 of the image generating unit, i.e., an image generated by light before being reflected by a concave mirror (hereinafter also referred to as an emission surface image) 431. Fig. 27B shows a virtual image object X that is recognized by an occupant as a predetermined image after the emission surface image 431 shown in Fig. 27A is reflected by the concave mirror. Note that the image in this example displays information indicating the vehicle's traveling speed (50 km / h).

[0159] As shown in Fig. 27A, when the exit surface image 431 at the light exit surface 424 of the image generating unit according to the comparative example is a normal image, for example, an image that has not been subjected to a predetermined correction process for distortion caused by reflection by a concave mirror, the virtual image object X generated by the light reflected by the concave mirror is displayed as an image with a distorted shape, as shown in Fig. 27B. In this example, the virtual image object X is displayed as an image with an expanded upper side and a contracted lower side.

[0160] In contrast, in the image generation unit 24 of the HUD 320 according to the ninth embodiment, in order to correct the image distortion caused by reflection from the concave mirror 27, an inverse correction process (also called a warping correction process) is performed in advance on the exit surface image.

[0161] Fig. 28 shows an example of exit surface images 331, 332 generated by light emitted from the image generation unit 24 of the HUD 320. Fig. 29 shows the exit surface images 331, 332 shown in Fig. 28 reflected by the concave mirror 27 and displayed as virtual image objects in front of the vehicle. 28, the light exit surface 124 of the image generating unit 24 is formed in a rectangular shape and is provided with a first light exit surface 124A and a second light exit surface 124B. An exit surface image 331 is generated by the light emitted from the first light exit surface 124A, and an exit surface image 332 is generated by the light emitted from the second light exit surface 124B. In this example, the exit surface image 331 displays a speed image notifying the driver that the current driving speed is 50 km / h and an attention drawing image (angle brackets) that alerts the driver. In addition, the exit surface image 332 displays an attention drawing image (angle brackets) that alerts the driver.

[0162] The first light emitting surface 124A of the rectangular light emitting surface 124 is formed, for example, as an annular sector-shaped emission surface. The annular sector-shaped first light emitting surface 124A forms a rectangular maximum display range 351 in which the virtual image object Ia shown in FIG. 29 is displayed. That is, the first light emitting surface 124A is preferably formed to occupy an area on the light emitting surface 124 in which the annular sector expands to its maximum extent. The second light emitting surface 124B of the rectangular light emitting surface 124 is formed as an emission surface in an area other than the first light emitting surface 124A. That is, the second light emitting surface 124B forms a rectangular display range 352 in which the virtual image object Ib shown in FIG. 29 is displayed, in an area other than the maximum display range 351 in which the virtual image object Ia is displayed. In this example, the second light emitting surface 124B is formed in an area of ​​the annular sector-shaped first light emitting surface 124A that is closer to the inner arc 342 than the outer arc 341. Specifically, the second light emitting surfaces 124B are formed on both the left and right sides of a lower region of the first light emitting surface 124A that has a narrower left-right width. In this way, in the light emitting surface 124, the first light emitting surface 124A is formed larger than the second light emitting surface 124B.

[0163] In order to correct distortion caused by reflection on the concave mirror 27, the output surface image 331 of the first light output surface 124A and the output surface image 332 of the second light output surface 124B are subjected to inverse correction (warping) in which the images are distorted in advance in the opposite direction by the amount of distortion caused by reflection on the concave mirror 27. In this example, the output surface images 331 and 332 are subjected to correction to extend the upper side of the image and to shrink the lower side.

[0164] 27B, the amount of distortion that occurs in the virtual image object I due to reflection on the concave mirror 27 decreases toward the center of the virtual image object I and increases away from the center. Therefore, the amount of correction by warping applied to the exit surface images 331, 332 that are the original images of the virtual image object I differs depending on the position of the exit surface images 331, 332 in accordance with the magnitude of the amount of distortion at each location on the virtual image object I. For example, the amount of correction of the exit surface image at a position corresponding to the center of the virtual image object I is relatively small, and the amount of correction of the exit surface image at a position corresponding to a location away from the center is relatively large.

[0165] In this example, the exit surface image 332 of the second light exit surface 124B is displayed in an area close to an inner arc 342 of the first light exit surface 124A, which is a large annular sector formed in the center of the light exit surface 124. The exit surface image 332 is an image displayed in an area away from the center of the light exit surface 124. The exit surface image 331 of the first light exit surface 124A is an image at a position corresponding to the center of the virtual image object I. The exit surface image 332 of the second light exit surface 124B is an image at a position corresponding to a portion away from the center of the virtual image object I. For this reason, the image generation unit 24 generates the exit surface images 331, 332 on the light exit surface 124 so that a correction coefficient for correcting distortion caused by light constituting the exit surface image 332, which is the original image of the virtual image object Ib, being reflected by the concave mirror 27 is larger than a correction coefficient for correcting distortion caused by light constituting the exit surface image 331, which is the original image of the virtual image object Ia, being reflected by the concave mirror 27. In other words, when correcting distortion caused in the virtual image object I, the correction amount of the exit surface image 332 displayed on the second light exit surface 124B is larger than the correction amount of the exit surface image 331 (average correction amount of the entire exit surface image 331).

[0166] As described above, the exit surface images 331 and 332 have been subjected to inverse correction processing in which they are distorted in advance in the opposite direction by the amount of distortion caused by reflection on the concave mirror 27. Therefore, when the light that generates the exit surface images 331 and 332 is reflected by the concave mirror 27, they are visually recognized as undistorted virtual image objects I (Ia, Ib), as shown in FIG. 29. The virtual image object Ia is an image generated by the exit surface image 331 of the first light exit surface 124A. The virtual image object Ib is an image generated by the exit surface image 332 of the second light exit surface 124B.

[0167] The virtual image object Ia and the virtual image object Ib are configured so that the position where the virtual image object Ia is recognized and the position where the virtual image object Ib is recognized are substantially the same in front of the vehicle 1. That is, the distance from the windshield 18 to the virtual image object Ia and the distance from the windshield 18 to the virtual image object Ib are configured so that they are substantially the same distance.

[0168] The virtual image object Ib is displayed adjacent to the virtual image object Ia around the virtual image object Ia. In this example, the virtual image objects Ib are displayed on the left and right of the virtual image object Ia as viewed by the occupants of the vehicle 1. The information displayed by the virtual image object Ia and the information displayed by the virtual image object Ib may be configured to be mutually associated information. As an example, the virtual image object Ia displays speed information (50 km / h) notifying the driving speed and attention-calling information (angle bracket pattern) that calls attention to the driving speed. Furthermore, the virtual image object Ib displays attention-calling information (angle bracket pattern) that calls attention to the notification content of the virtual image object Ia. The angle bracket pattern of the virtual image object Ib is displayed adjacent to the angle bracket pattern of the virtual image object Ia on the left or right side to form a continuous angle bracket pattern. The display range of the image viewed as the virtual image object I is the image range obtained by adding together the virtual image object Ia (first image) formed by the light emitted from the first light emitting surface 124A and the virtual image object Ib (second image) formed by the light emitted from the second light emitting surface 124B.

[0169] As described above, the HUD 320 according to this embodiment includes the image generation unit 24 that emits light for generating a virtual image object I (a predetermined image), and the concave mirror 27 (an example of a reflector) that reflects the light emitted by the image generation unit 24 so that the light is irradiated onto the windshield 18. On the light emission surface 124 of the image generation unit 24, an area capable of forming a rectangular maximum display range 351 in which a virtual image object Ia (an example of a first image), which is a part of the virtual image object I, is displayed is defined as the first light emission surface 124A (an example of a first area), and an area other than the first light emission surface 124A is defined as the second light emission surface 124B (an example of a second area).The HUD 320 is configured so that a virtual image object Ib (an example of a second image), which is different from the virtual image object Ia, is displayed by light emitted from the second light emission surface 124B outside the maximum display range 351 in which the virtual image object Ia can be displayed by light emitted from the first light emission surface 124A. According to this configuration, by providing the second light emitting surface 124B in addition to the first light emitting surface 124A within the light emitting surface 124 of the image generating unit 24, it is possible to provide a display range 352 in which the virtual image object Ib is displayed in an area outside the rectangular maximum display range 351 in which the virtual image object Ia is displayed. Therefore, the display range of the virtual image (image) can be wider than in a conventional HUD in which the image generating unit has only a single light emitting surface (see FIG. 27A ).

[0170] Furthermore, in the HUD 320 according to this embodiment, the light emitting surface 124 is formed in a rectangular shape, the first light emitting surface 124A is formed as an annular sector-shaped region of the rectangular light emitting surface 124, and the second light emitting surface 124B is formed in a region of the light emitting surface 124 that is closer to the inner arc than the outer arc of the annular sector-shaped first light emitting surface 124A. With this configuration, the portions of the rectangular light emitting surface 124 other than the annular sector-shaped first light emitting surface 124A, specifically, the left and right sides of the lower region of the annular sector-shaped first light emitting surface 124A, which has a narrow left-right width, can be efficiently used as regions where the second light emitting surface 124B is formed. This makes it possible to expand the display range of the virtual image (image) while suppressing the increase in size of the light emitting surface 124, which would be expensive.

[0171] Furthermore, in the HUD 320 according to this embodiment, a correction coefficient for correcting, in the image generation unit 24, distortion of the virtual image object Ib caused by light constituting the original image (exit surface image 332) of the virtual image object Ib generated by the image generation unit 24 being reflected by the concave mirror 27 is configured to be larger than a correction coefficient for correcting, in the image generation unit 24, distortion of the virtual image object Ia caused by light constituting the original image (exit surface image 331) of the virtual image object Ia generated by the image generation unit 24 being reflected by the concave mirror 27. Since the second light exit surface 124B is formed closer to the outer edge of the light exit surface 124 of the image generation unit 24 than the first light exit surface 124A, the virtual image object Ib is more likely to be distorted by reflection at the concave mirror 27 than the virtual image object Ia. Therefore, by making the correction coefficient of the virtual image object Ib displayed on the second light emitting surface 124B larger than the correction coefficient of the virtual image object Ia displayed on the first light emitting surface 124A, the distortion of the virtual image object Ib with a large amount of distortion can be appropriately corrected.

[0172] Furthermore, according to the HUD 320, virtual image objects Ib may be displayed on the left and right of the virtual image object Ia, and the contents of information displayed by the respective images of the virtual image objects Ia and Ib may be associated with each other. For example, attention-calling information (angle brackets) displayed as the virtual image object Ia and attention-calling information (angle brackets) displayed as the virtual image object Ib may be displayed in sequence. In this way, various types of information can be provided to the occupant through cooperation between the virtual image object Ia and the virtual image object Ib.

[0173] It should be noted that third light emitting surfaces (not shown) may be provided at the upper left and right corners of the light emitting surface 124 in FIG. 28. The correction coefficient of the third light emitting surface is preferably set to be larger than the correction coefficient of the first light emitting surface 124A, similar to the second light emitting surface 124B. The light emitted from the third light emitting surface displays a virtual image object below the lower left and right ends of the virtual image object Ia in FIG. 29. In this way, by effectively utilizing the areas of the light emitting surface 124 other than the first light emitting surface 124A and the second light emitting surface 124B as the third light emitting surface, the display range of the virtual image (image) can be further expanded.

[0174] (Variation) FIG. 30 is a schematic diagram showing the configuration of a HUD 320A according to a modified example. As shown in FIG. 30 , a HUD 320A according to the modified example includes a HUD main body 21 and a combiner 19. The combiner 19 is provided inside the windshield 18 as a separate structure from the windshield 18. The combiner 19 is, for example, a transparent plastic disk, and light emitted from a light emitting surface 124 and reflected by a concave mirror 27 is irradiated onto the combiner 19 in place of the windshield 18. As a result, a portion of the light irradiated onto the combiner 19 from the HUD main body 21 is reflected toward the occupant's viewpoint E, similar to the case where light is irradiated onto the windshield 18. As a result, the occupant can recognize the light (predetermined image) emitted from the HUD main body 21 as a virtual image object I formed at a predetermined distance in front of the combiner 19 (and the windshield 18). The HUD 320A equipped with such a combiner 19 can also achieve the same effects as the HUD 20 described above.

[0175] Although the embodiments of the present disclosure 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 the present embodiments. The present 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.

[0176] The optical isolator 70 as described in the first embodiment may be provided in a light emitting device such as a projector configured to display a predetermined image on an object such as an outdoor wall. That is, in the projector, the optical isolator may be disposed, for example, at a position where light from the light source passes between the light source and an optical element (such as a lens) or between the optical element and an image display object. This makes it possible to provide a projector that can prevent heat damage caused by external light entering the light source without reducing the light emitting function.

[0177] In the third and fourth embodiments, the first and second images (or the first, second, and third images) are simultaneously displayed, but this is not limiting. For example, only one image may be displayed depending on the HUD information to be displayed.

[0178] In the third embodiment, the base member 40 of the concave mirror 30 is formed from a single (monolithic) member, but this is not limiting. For example, the base member may be formed by integrating multiple base members corresponding to multiple reflective areas with or without gaps. The reflective film 50 may be formed on the multiple base members collectively, or may be formed on each base member separately.

[0179] In the modification of the third embodiment, the concave mirror 130 is formed by integrating the first base member 141 and the second base member 142 in a state where they are in contact with each other, but this is not limited to this. For example, the first base member 141 and the second base member 142 may be integrated by being adjacent to each other with a gap in between. When a concave mirror is formed by integrating multiple base members with gaps in between, the operation of the image generation unit 24 may be controlled so that light is not irradiated onto the portions corresponding to the gaps.

[0180] In the third and fourth embodiments, the reflecting unit is a concave mirror 30, 130, or 230, but is not limited to this. For example, the reflecting unit may be a flat mirror having a reflecting surface including a plurality of reflecting areas with different surface roughnesses. This allows the reflecting unit to be realized at low cost without significantly degrading the image quality of the virtual image.

[0181] In the third and fourth embodiments, the concave mirrors 30, 130, and 230 are composed of a base member 40, 140, and 240 and a reflective film 50, 150, and 250, but this is not limiting. For example, a top coat for corrosion prevention may be formed on the reflective film. The top coat is formed, for example, from a transparent resin, and light emitted from the image generation unit 24 passes through the top coat and is reflected by the reflective film. In other words, since the rear surface of the reflective film forms the reflective surface of the concave mirror, the surface roughness of the rear surface of the top coat may be uniform. The surface roughness of the rear surface of the top coat (the surface irradiated with light emitted from the image generation unit 24) may be changed by forming the top coat as a thin film so that it is affected by the surface of the reflective film.

[0182] In the third and fourth embodiments, the base members 40, 140, and 240 of the concave mirrors 30, 130, and 230 are made of different materials or have different surface roughnesses to form the reflecting surfaces 31, 131, and 231. However, this is not limiting. For example, the base members 40, 140, and 240 may have the same surface roughness or be made of the same material, and the reflecting films 50, 150, and 250 may have different surface roughnesses or be made of different materials to form the reflecting surfaces.

[0183] In the third and fourth embodiments, the concave mirror 30, 130, 230 is formed of a reflective area divided vertically or horizontally into two or three areas, but is not limited to this. The shape of the divided reflective area may be determined depending on the position or area of ​​the windshield 18 that the driver frequently looks at.

[0184] In the third and fourth embodiments described above, the concave mirrors 30, 130, 230 reflect the light emitted from the image generation unit 24 toward the windshield 18, but this is not limiting. The concave mirrors 30, 130, 230 may also reflect the light toward a combiner provided inside the windshield 18.

[0185] In the third and fourth embodiments, light that forms predetermined images including a first image, a second image, and a third image is emitted via one display device of the image generation unit 24, but this is not limited to this. The image generation unit 24 may have a first display device that emits light that forms the first image, a second display device that emits light that forms the second image, and a third display device that emits light that forms the third image. In this case, light sources and optical components are provided corresponding to each display device.

[0186] In the above-described fourth embodiment, the case where the light emitted by the HUD 120 is irradiated onto an area of ​​the windshield 18 that is located below the center line C has been described, but this is not limiting. When the light emitted by the HUD 120 is irradiated onto an area of ​​the windshield 18 that is located above the center line C, the concave mirror 30 may be formed, for example, so that the first reflection area 31A is positioned below the second reflection area 31B. In this case, the first light reflected by the first reflection area 31A is irradiated onto an area on the windshield 18 that is located above the area irradiated by the second light reflected by the second reflection area 31B.

[0187] In the fifth to eighth embodiments, the image generator 24 may be configured to generate the second image so that its size is larger than that of the first image. The image generator 224 may also be configured to generate the second and third images so that their sizes are larger than that of the first image. The concave mirrors 126A and 226A reflect the first light so that the first image expands, while the plane mirrors 126B and 226B reflect the second light without changing the size of the second image. The plane mirrors 126C and 226C also reflect the third light without changing the size of the third image. Therefore, the size of the virtual image of the first image is larger than that of the virtual image of the second image. The size of the virtual image of the first image is larger than that of the virtual image of the third image. This difference in size of the virtual images may cause discomfort to the driver. According to the above configuration, the size of the virtual images of the second image (and the third image) is increased, thereby reducing the discomfort felt by the driver due to the difference in size of the virtual images.

[0188] Furthermore, in the fifth to eighth embodiments, light that forms predetermined images including a first image, a second image, and a third image is emitted via a single display device of the image generation unit 24, 224. However, this is not limited to this. The image generation unit 24 may include a first generation unit that generates the first image and a second generation unit that generates the second image. The image generation unit 224 may include a first generation unit that generates the first image, a second generation unit that generates the second image, and a third generation unit that generates the third image. Light sources and optical components are provided corresponding to each generation unit. In this case, the first image may be a color image, and the second image (and the third image) may be monochrome images. With this configuration, because the second image is a monochrome image, the second generation unit (and the third generation unit) can be implemented at low cost, and as a result, the image generation unit can be implemented at low cost.

[0189] In the fifth to eighth embodiments, the first and second images (or the first, second, and third images) are simultaneously displayed, but this is not limiting. For example, only one image may be displayed depending on the HUD information to be displayed.

[0190] Furthermore, the arrangement direction and number of the concave mirrors and plane mirrors that make up the reflecting section are not limited to the vertical or horizontal arrangement and two or three arrangements in the above embodiment.

[0191] In the fifth to eighth embodiments, the reflecting units 126, 226 reflect the light emitted from the image generating units 24, 224 toward the windshield 18, but this is not limiting. The reflecting units 126, 226 may also reflect the light toward a combiner provided inside the windshield 18.

[0192] In the sixth and eighth embodiments, one or two lenses 28, 80 are used as the optical element disposed between the image generating unit 24, 224 and the plane mirror 126B, 226B, 226C, but this is not limiting. A mirror may be used as the optical element instead of or in addition to a lens. For example, multiple plane mirrors may be disposed between the image generating unit 24, 224 and the plane mirror 126B, 226B, 226C.

[0193] In the first to ninth embodiments, the vehicle driving modes are described as including a fully automated driving mode, an advanced driving assistance mode, a driving assistance mode, and a manual driving mode. However, the vehicle driving modes should not be limited to these four modes. The vehicle driving modes may include at least one of these four modes. For example, the vehicle driving modes may be executable in only one of the four modes.

[0194] Furthermore, the classification and display format of the vehicle 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 the "fully autonomous driving mode," "advanced driving assistance mode," and "driving assistance mode" described in the explanations of the first to ninth embodiments 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.

[0195] This application is based on Japanese Patent Application No. 2019-179484 filed on September 30, 2019, Japanese Patent Application No. 2019-197510 filed on October 30, 2019, Japanese Patent Application No. 2019-197511 filed on October 30, 2019, and Japanese Patent Application No. 2019-211328 filed on November 22, 2019, the contents of which are incorporated herein by reference.

Claims

1. A head-up display provided in a vehicle and configured to display a predetermined image toward an occupant of the vehicle, an image generating unit that emits first light for generating a first image of the predetermined images and second light for generating a second image of the predetermined images; a reflecting unit that reflects the first light and the second light emitted by the image generating unit so that the first light and the second light are irradiated onto a windshield or a combiner, the reflecting portion has a reflecting surface including a first reflecting area that reflects the first light and a second reflecting area that reflects the second light, A head-up display, wherein the first reflective area has a first surface roughness, and the second reflective area has a second surface roughness that is rougher than the first surface roughness.

2. The head-up display according to claim 1 , wherein the reflecting portion is a concave mirror.

3. the reflecting portion has a base member and a reflective film formed on the base member, the reflective film forms the reflective surface, The head-up display according to claim 1 or 2, wherein a surface roughness of the base member corresponding to the second reflective area is greater than a surface roughness of the base member corresponding to the first reflective area.

4. the reflecting portion has a base member and a reflective film formed on the base member, the reflective film forms the reflective surface, The head-up display according to claim 1 , wherein a base member corresponding to the first reflective area and a base member corresponding to the second reflective area are made of different materials.

5. 5. The head-up display according to claim 1, wherein the first reflective area and the second reflective area are arranged side by side in a vertical direction of the vehicle so that the first light is irradiated onto the windshield or the combiner at a position closer to a vertical center of the windshield than the second light.

6. the image generation unit emits third light for generating a third image of the predetermined image, the reflecting surface of the reflecting unit has a third reflecting area that reflects the third light, the third reflective area has a third surface roughness that is rougher than the first surface roughness; 5. The head-up display according to claim 1, wherein the first reflective area, the second reflective area, and the third reflective area are arranged side by side in a horizontal direction of the vehicle, with the first reflective area sandwiched between the second reflective area and the third reflective area.

7. A head-up display provided in a vehicle and configured to display a predetermined image toward an occupant of the vehicle, an image generating unit that emits light for generating the predetermined image; a reflecting unit that reflects the light emitted by the image generating unit so that the light is irradiated onto a windshield or a combiner, a first region is a region on the light output surface of the image generating unit that can form a rectangular maximum display range in which a first image that is a part of the predetermined image is displayed, and a second region is a region other than the first region; A head-up display in which a second image different from the first image is displayed by light emitted from the second area outside the maximum display range in which the first image can be displayed by light emitted from the first area, the distance from the windshield or the combiner to the first image and the distance from the windshield or the combiner to the second image are substantially the same, and the second images are arranged to the left and right of the first image.

8. the reflecting portion is composed of a concave mirror, 8. The head-up display of claim 7, wherein a correction coefficient for correcting in the image generation unit distortion of the second image caused by light constituting the original image of the second image generated by the image generation unit being reflected by the concave mirror is greater than a correction coefficient for correcting in the image generation unit distortion of the first image caused by light constituting the original image of the first image generated by the image generation unit being reflected by the concave mirror.

9. The light exit surface is formed in a rectangular shape, the first region is formed as an annular sector-shaped region of the rectangular light exit surface, The head-up display according to claim 7 or 8, wherein the second region is formed in a region of the light exit surface that is closer to an inner arc than an outer arc of the first region of the annular sector.

10. The head-up display according to claim 7 , wherein information displayed by the first image and information displayed by the second image are associated with each other.

Images