Virtual image display device

Abstract

To provide a technology capable of reducing power consumption while appropriately displaying necessary information about a technology of a virtual display device, and to contribute to "Ensure healthy lives and promote well-being for all at all ages" of Sustainable Development Goal 3 according to this invention.SOLUTION: A virtual image display device 10A includes: a video formation unit 12 including a light source device 13 having a plurality of light sources and a display panel 15 for forming a plurality of display areas in which a video is displayed and which respectively correspond to the light sources; and a processor 20 for controlling the video formation unit 12. The processor 20 controls the display of the display areas, thereby changing the display state of the display panel such that the number of areas in which the video is displayed among the plurality of display areas decreases.SELECTED DRAWING: Figure 5A

Description

[Technical Field]

[0001] The present disclosure relates to a technology for a virtual image display device such as a head-up display (HUD). [Background technology]

[0002] As a HUD device to be mounted on a vehicle or the like, a HUD device has been developed that forms a virtual image in front of the driver on a transparent member such as a windshield or a combiner (a dedicated display board) as seen from the driver's point of view.

[0003] An example of prior art is Japanese Patent Application Laid-Open No. 2020-112668 (Patent Document 1). Patent Document 1 describes an example of a head-up display device that has an image display unit having multiple image areas and multiple light sources, and performs local dimming control to light up corresponding light sources for each screen area based on the arrangement of display content. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-112668 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in Patent Document 1 is aimed solely at providing a HUD device with good visibility of the virtual image, and does not take into consideration reducing the power consumption of the HUD device.

[0006] An object of the present disclosure is to provide a technology for reducing power consumption while appropriately displaying necessary information, in relation to the technology of virtual image display devices such as the HUD devices. [Means for solving the problem]

[0007] A representative embodiment of the present disclosure has the following configuration: A virtual image display device of the embodiment displays a virtual image by projecting image light onto a projection area of a vehicle windshield, and includes an image forming unit having a plurality of light sources and a display panel that displays images and forms a plurality of display areas corresponding to the light sources, and a processor that controls the image forming unit, and the processor controls the display of each display area to change the display state of the display panel so as to reduce the number of areas among the plurality of display areas in which images are displayed. [Effects of the Invention]

[0008] According to a representative embodiment of the present disclosure, the technology of the virtual image display device can reduce power consumption while appropriately displaying necessary information. Problems, configurations, effects, etc. other than those described above are described in the description of the embodiment of the present disclosure. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a vehicle equipped with a virtual image display device according to an embodiment. [Figure 2] FIG. 2 is a diagram showing an example of a functional block configuration of a controller of a vehicle on which a virtual image display device is mounted. [Figure 3] FIG. 1 is a diagram showing an example of a HUD device according to a first exemplary configuration. [Figure 4] FIG. 10 is a diagram showing an example of a display device according to a second configuration example. [Figure 5A] FIG. 2 is a diagram showing a first example of a functional block configuration of a HUD device according to configuration example 1. [Figure 5B] FIG. 10 is a diagram showing a second example of the functional block configuration of the HUD device according to the first configuration example. [Figure 6A] FIG. 10 is a diagram showing a first example of a functional block configuration of a display device according to Configuration Example 2. [Figure 6B] FIG. 10 is a diagram showing a second example of the functional block configuration of the display device according to the second configuration example. [Figure 7] FIG. 2 is a diagram showing an example of an image forming unit included in the HUD device according to the first exemplary configuration. [Figure 8] FIG. 10 is a diagram showing an example of an image forming unit included in a display device according to a second configuration example. [Figure 9] FIG. 10 is a diagram showing an example of an image forming unit included in a display device according to a second configuration example. [Figure 10] FIG. 10 is a diagram showing a modified example of the image forming section included in the display device according to the second configuration example. [Figure 11] FIG. 10 is a diagram showing a modified example of the image forming section included in the display device according to the second configuration example. [Figure 12] 1 is a diagram showing a display image of a projection area in a vehicle equipped with a virtual image display device according to an embodiment. [Figure 13A] FIG. 10 is a diagram showing a display image of a projection area according to an embodiment. [Figure 13B] FIG. 10 is a diagram showing a display image of a projection area according to an embodiment. [Figure 14] FIG. 10 is a diagram showing another example of a projection area in a vehicle equipped with the virtual image display device of the embodiment. [Figure 15A] FIG. 10 is a diagram showing another example of a display image in a projection area according to an embodiment. [Figure 15B] FIG. 10 is a diagram showing another example of a display image in a projection area according to an embodiment. [Figure 15C] FIG. 10 is a diagram showing another example of a display image in a projection area according to an embodiment. [Figure 16] FIG. 10 is a diagram showing another example of a projection area in a vehicle equipped with the virtual image display device of the embodiment. [Figure 17A] FIG. 10 is a diagram showing another example of a display image in a projection area according to an embodiment. [Figure 17B] FIG. 10 is a diagram showing another example of a display image in a projection area according to an embodiment. [Figure 18] FIG. 10 is a diagram showing another example of a projection area in a vehicle equipped with the virtual image display device of the embodiment. [Figure 19] 10 is a flowchart showing an example of image formation control by the virtual image display device of the embodiment. [Figure 20] 10A to 10C are diagrams illustrating a specific example of a determination process in video display control according to an embodiment. [Figure 21]10 is a flowchart showing an example of local dimming control by the virtual image display device of the embodiment. [Figure 22A] 5A and 5B are diagrams illustrating a specific example of local dimming control according to an embodiment. [Figure 22B] 5A and 5B are diagrams illustrating a specific example of local dimming control according to an embodiment. [Figure 23A] FIG. 2 is a diagram showing an example of a display state of a display panel according to an embodiment. [Figure 23B] FIG. 2 is a diagram showing an example of a display state of a display panel according to an embodiment. [Figure 23C] FIG. 2 is a diagram showing an example of a display state of a display panel according to an embodiment. [Figure 24A] FIG. 2 is a diagram showing an example of a display state of a display panel according to an embodiment. [Figure 24B] FIG. 2 is a diagram showing an example of a display state of a display panel according to an embodiment. [Figure 25A] FIG. 2 is a diagram showing an example of a display state of a display panel according to an embodiment. [Figure 25B] FIG. 2 is a diagram showing an example of a display state of a display panel according to an embodiment. [Figure 25C] FIG. 2 is a diagram showing an example of a display state of a display panel according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same parts are generally designated by the same reference numerals, and repeated explanations will be omitted. In the drawings, the representation of components may not represent their actual positions, sizes, shapes, ranges, etc., in order to facilitate understanding of the invention.

[0011] For the sake of explanation, when describing processing by a program, the program, function, processing unit, etc. may be described as the main body, but the main hardware body for these is a processor, or a controller, device, computer, system, etc. that is configured with the processor, etc. A computer executes processing according to a program read into memory using resources such as memory and communication interfaces as appropriate through the processor. This realizes predetermined functions, processing units, etc. A processor is configured, for example, with semiconductor devices such as a CPU / MPU or GPU. Processing is not limited to software program processing, but can also be implemented using dedicated circuits. Dedicated circuits such as FPGAs, ASICs, and CPLDs can be used.

[0012] The program may be pre-installed as data on the target computer, or may be distributed to the target computer as data from a program source. The program source may be a program distribution server on a communication network, or a non-transitory computer-readable storage medium such as a memory card or a disk. The program may be composed of multiple modules.

[0013] In addition, in the drawings, (X, Y, Z) may be used as a coordinate system or direction for explanatory purposes. (X, Y, Z) in the drawings indicates a spatial coordinate system relative to the vehicle. The X-axis and X-direction are the left-right direction of the vehicle, and if the road surface on which the vehicle is traveling is a horizontal plane, the X-direction can also be considered a first horizontal direction. The Y-axis and Y-direction are the front-rear direction of the vehicle, and if the X-direction is the first horizontal direction, the Y-direction can also be considered a second horizontal direction perpendicular to the X-direction. Furthermore, the Z-axis and Z-direction are the up-down direction of the vehicle, and if the X-direction is the first horizontal direction and the Y-direction is the second horizontal direction, the Z-direction can also be considered a vertical direction.

[0014] [In-vehicle system] Fig. 1 is a diagram showing an example of the configuration of an in-vehicle system including a virtual image display device. As shown in Fig. 1, a vehicle 1 is equipped with a virtual image display device 10 and a controller 100 as an in-vehicle system 300. That is, the in-vehicle system 300 equipped in the vehicle 1 is configured to include the virtual image display device 10 and the controller 100. In this embodiment, a HUD device 10A or a display device 10B will be described as an example of the virtual image display device 10.

[0015] The HUD device 10A projects image light onto a projection area (sometimes called a display area) 3 on a windshield or front glass 2. The virtual image display device 10 includes an image display device, which will be described later, and projects an image displayed on this image display device onto the projection area 3 on the windshield (also called a front glass) 2. As a result, the image projected onto the projection area 3 is visually recognized by the driver of the vehicle 1 or the like as a virtual image formed in front of the windshield 2.

[0016] The controller 100 is a control device / control unit also called, for example, an ECU (Electronic Control Unit), and controls all or part of the in-vehicle system 300. The HUD device 10A and the controller 100 are connected by an information transmission path 200 configured with an interface such as a CAN (Controller Area Network), and are capable of communicating with each other. In this example, the information transmission path 200 is configured with two information transmission paths: a first information transmission path and a second information transmission path.

[0017] The controller 100 acquires vehicle information 4 using various sensors, measurement devices, communication devices, etc. as shown in Fig. 2. Then, the controller 100 controls the virtual image display device 10 through an information transmission path 200 such as a CAN to display an image based on the vehicle information 4 as a virtual image in the projection area 3 of the windshield 2 as seen by the driver. In other words, the virtual image display device 10 acquires image data based on the vehicle information 4 from the controller 100 through the information transmission path 200 such as a CAN, and emits image light based on the acquired image data. Alternatively, the virtual image display device 10 generates image data based on the vehicle information 4, etc. acquired and input from the controller 100, and emits image light based on the generated image data.

[0018] [Controller-related function blocks] 2 is a diagram showing an example of a functional block configuration of the controller 100. As shown in Fig. 2, various sensors and devices connected to the controller 100 include, for example, a vehicle speed sensor 201, a shift position sensor 202, a steering wheel steering angle sensor 203, a headlight sensor 204, an illuminance sensor 205, a chromaticity sensor 206, a distance measurement sensor 207, an infrared sensor 208, an engine start sensor 209, an acceleration sensor 210, a gyro sensor 211, a temperature sensor 212, a wireless transceiver for road-to-vehicle communication 213, a wireless transceiver for vehicle-to-vehicle communication 214, a camera (in-vehicle camera) 215, a camera (out-vehicle camera) 216, a GPS receiver 217, and a VICS (Vehicle Information and Communication System, registered trademark) receiver 218. The sensors and devices connected to the controller 100 are not limited to those described above, and may be added, deleted, or replaced as necessary.

[0019] The vehicle speed sensor 201 detects the speed of the vehicle 1 (also referred to as vehicle speed) and generates speed information as the detection result. The shift position sensor 202 detects the current gear and generates gear information as the detection result. The steering wheel angle sensor 203 detects the current steering wheel angle and generates steering wheel angle information as the detection result. The headlight sensor 204 detects whether the headlights are on / off, etc. and generates lamp illumination information as the detection result. The illuminance sensor 205 and the chromaticity sensor 206 detect external light (e.g., sunlight) and generate external light information as the detection result.

[0020] The distance measurement sensor 207 detects the distance between the vehicle 1 and an external object, and generates distance information as the detection result. The infrared sensor 208 detects the presence or absence of an object in the vicinity of the vehicle 1, as well as the distance, and generates infrared information as the detection result. The engine start sensor 209 detects whether the engine is on or off, and generates on or off information as the detection result. The acceleration sensor 210 and gyro sensor 211 detect the acceleration and angular velocity of the vehicle 1, and generate acceleration gyro information representing the attitude and behavior of the vehicle 1 as the detection result. The temperature sensor 212 detects the temperature inside and outside the vehicle 1, and generates temperature information as the detection result.

[0021] The road-to-vehicle communication wireless transceiver 213 generates road-to-vehicle communication information through road-to-vehicle communication between the vehicle 1 and roads, signs, traffic lights, etc. The vehicle-to-vehicle communication wireless transceiver 214 generates vehicle-to-vehicle communication information through vehicle-to-vehicle communication between the vehicle 1 and other vehicles in the vicinity.

[0022] The in-vehicle camera 215 captures images of the interior of the vehicle 1 to generate in-vehicle camera video information. The exterior camera 216 captures images of the exterior of the vehicle 1 to generate in-vehicle camera video information. The in-vehicle camera 215 captures the driver's posture, eye position, and movement, and may constitute a DMS (Driver Monitoring System). The exterior camera 216 captures images of the surrounding conditions, such as the area ahead of the vehicle 1. By analyzing the image information captured by the exterior camera 216, it is possible to determine the presence or absence of other vehicles or people around the vehicle 1, buildings, topography, road conditions such as rain, snow, ice, and unevenness, and road signs. The exterior camera 216 may also function as a drive recorder that records images of the conditions while the vehicle 1 is traveling.

[0023] The GPS receiver 217 generates GPS information by receiving GPS signals from GPS satellites. The GPS information includes information such as the current time, latitude, and longitude. The VICS receiver 218 generates VICS information by receiving VICS signals. The GPS receiver 217 and the VICS receiver 218 may be provided as part of a navigation system.

[0024] [Configuration example 1 of virtual image display device] FIG. 3 is a schematic diagram showing an example of the configuration of the virtual image display device in FIG. 1. As shown in FIG. 3, a HUD device 10A, which is a virtual image display device 10 of configuration example 1, is housed in the dashboard 5 of a vehicle 1. The HUD device 10A includes an image forming section (which may also be referred to as an image forming unit) 12 and an image projection section. The image forming section 12 is, for example, a projector or a liquid crystal display (LCD), and displays an image based on input image data and emits image light of the displayed image. In this embodiment, the image forming section 12 more specifically includes a light source device 13, optical components 14, and a display panel 15. Alternatively, the image forming section 12 may be composed only of the display panel 15, such as a micro LED display, which is composed of an array of tiny LEDs that form individual pixel elements. The image projection section includes reflective mirrors M1 and M2, and the reflective mirror M1 may not be provided depending on the design.

[0025] The light source device 13 includes, for example, an LED (Light Emitting Diode) light source or a laser light source, and irradiates light onto the display panel 15. In this example, the light source device 13 is provided so as to face the display panel 15 when viewed in the Z direction. The light source device 13 turns on the backlight, i.e., turns on the light source, when controlled to be on, and turns off the backlight when controlled to be off. As will be described in more detail later, the light source device 13 includes multiple light sources, and the on / off of these multiple light sources is controlled individually.

[0026] The optical component 14 is, for example, a lens for the light source, and adjusts the optical path of the backlight from the light source device 13 so that the backlight is uniformly irradiated onto a predetermined area of the display panel 15. The display panel 15 is typically a liquid crystal panel. The display panel 15 displays an image by modulating the backlight from the light source device 13 in accordance with input video data, more specifically, by modulating the transmittance for each pixel.

[0027] The reflecting mirrors M1 and M2 are arranged in the optical path of the image light emitted from the image forming unit 12 and project the reflected image light onto the projection area 3 of the windshield 2. The reflecting mirror M1 is, for example, a plane mirror and is provided on the optical path of the image light between the image forming unit 12 and the reflecting mirror M2 and reflects the image light towards the reflecting mirror M2. The reflecting mirror M2 is, for example, a concave mirror (magnifying mirror) and is provided on the optical path of the image light between the display panel 15 and the projection area 3 of the windshield 2 and reflects the image light towards the projection area 3. In other words, the image light is reflected and magnified by the reflecting mirror M2 and projected onto the projection area 3 through an opening 6 formed in the dashboard 5.

[0028] The installation angle of the reflective mirror M1 is fixed. On the other hand, the installation angle of the reflective mirror M2 is variably adjusted via a drive mechanism 16. The drive mechanism 16 functions as a mirror driver and includes, for example, a motor, which rotates the reflective mirror M2 by rotating the motor. By adjusting the installation angle of the reflective mirror M2 and preventing external sunlight from reaching the display panel 15, it is possible to protect the display panel 15.

[0029] The image light projected onto the projection area 3 of the windshield 2 is reflected by this projection area 3 and enters the eyes of the driver 7. As a result, the driver sees the image light projected onto the projection area 3 as a virtual image 8 beyond the transparent windshield 2, superimposed on the scenery outside the vehicle (roads, buildings, people, etc.). Note that by rotating the reflecting mirror M2 with the drive mechanism 16, the position of the virtual image 8 seen by the driver 7 (the position of the projection area 3) can be adjusted in the vertical direction.

[0030] The information represented by the virtual image 8 includes various information such as road signs, the current speed of the vehicle, and various information added to objects in the landscape, i.e., AR (Augmented Reality) information. If the virtual image 8 is AR information, it is displayed superimposed according to the position of the object. If the virtual image 8 is not AR, it is displayed independently at a predetermined position. Furthermore, the vehicle 1 is typically an automobile, but is not limited to this and may be a railroad vehicle, an airplane, or the like.

[0031] [Configuration example 2 of virtual image display device] Fig. 4 is a schematic diagram showing an example of the configuration of the virtual image display device in Fig. 1. The HUD device 10A according to Configuration Example 1 is housed in the dashboard 5 of the vehicle 1, whereas the display device 10B, which is the virtual image display device 10 according to Configuration Example 2 shown in Fig. 4, is installed on top of the dashboard 5 of the vehicle 1.

[0032] The display device 10B (image display device 11) according to the second configuration example does not include reflection mirrors M1 and M2. The display device 10B according to the second configuration example is also called a mirror-type display device, and is a compact display device suitable for in-vehicle installation. It is equipped with image light control technology that enables image light to be directed and projected in any direction. The image light emitted from the display device 10B, which is a mirror-type display device, is reflected by a projection area 3A of the windshield 2. The reflected image light enters the eyes of the driver 7, and the driver views the image light as a virtual image 8. In the case of the second configuration example, the projection area 3A of the windshield 2 can be said to function as a projection member onto which the image light is projected, or as a mirror or a reflecting member. The projection area 3A that functions as this mirror (reflecting member) or projection member can be said to be one element that constitutes the mirror-type display device.

[0033] In this example, the mirror-type display device is described as being different from the HUD device, but the mirror-type display device may also be considered as a type of HUD device. Also, in configuration example 2, only the image forming unit 12A is shown as a component included in the image display device 11, but the image display device 11 may also include devices other than the image forming unit 12A. Also, the configuration of the image forming unit 12A is not particularly limited and is an existing configuration, so it will be briefly described below.

[0034] Image forming unit 12A has light source device 13A and display panel 15, and is equipped with an image light control technology that can guide and project image light in any direction. In the example shown in FIG. 4, the configuration of image forming unit 12A excluding display panel 15 is light source device 13A. Light source device 13A is configured with light source 131, light guide 132, etc., and converts the traveling direction of light generated based on light source 131 (in other words, light source light) using light guide 132, etc., and emits the light source light toward display panel 15. In image forming unit 12A according to configuration example 2, light source 131 and light guide 132 are arranged side by side in the Y direction. In other words, light source 131 and light guide 132 are arranged so as not to overlap when viewed in the Z direction. Furthermore, the light emission surface of light guide 132 is arranged to face display panel 15 when viewed in the Z direction. Of course, the arrangement of the light source 131 and the light guide 132 is merely an example, and is not limited to the above arrangement.

[0035] [HUD device function block (1)] Fig. 5A is a diagram showing an example of a functional block configuration of a HUD device according to Configuration Example 1. More specifically, Fig. 5A shows, as a first example of the functional block configuration of HUD device 10A according to Configuration Example 1, a configuration in which no image is generated inside HUD device 10A.

[0036] 5A, the HUD device 10A according to the first configuration example includes the above-described image display device 11, and further includes an MCU 20, a nonvolatile memory 21, a volatile memory 22, a communication unit 23, a display driver 24, a light source drive unit 25, etc., and these components are interconnected by an architecture such as a bus 26. In this embodiment, the image display device 11 includes an image formation unit 12, a reflecting mirror M1, and a reflecting mirror M2 having a drive mechanism (mirror drive unit) 16.

[0037] As is widely known, the MCU 20 includes a processor such as a CPU (Central Processing Unit) and various peripheral functions. Therefore, each block except for the MCU 20 may be appropriately mounted within the MCU 20. The HUD device 10A is not limited to being implemented using the MCU 20, but may be implemented using an ECU or other semiconductor devices. The processor (MCU) 20 shown in FIGS. 5A and 5B is mounted in the HUD device 10A and functions as a control unit that controls the HUD device 10A based on information from the vehicle 1. Although the present disclosure describes an embodiment in which the HUD device 10A includes the processor 20, the HUD device 10A may not include the processor 20. If the HUD device 10A does not include the processor 20, for example, the controller 100 of the vehicle 1 controls the HUD device 10A. When the controller 100 controls the HUD device 10A, the specific control content is the same as when the processor 20 controls the HUD device 10A.

[0038] The non-volatile memory 21 stores control programs, setting information, etc. The volatile memory 22 stores processing data, including display data for HUD display. The HUD device 10A may also include internal / external storage, etc., not shown, and programs and data may be stored in the storage, etc. The MCU 20 executes processing in accordance with programs read from the non-volatile memory 21, etc. This forms an execution module corresponding to each function.

[0039] The communication unit 23 includes a video receiving unit 27 and a communication processing unit 28. The communication interface of the information transmission path 200 in FIG. 1 is implemented in the communication unit 23. In this example, in correspondence with the redundant configuration of the information transmission path 200, at least an FPD-Link III as a first communication interface and a CAN as a second communication interface are implemented. Specifically, the communication unit 23 includes a video receiving unit 27 corresponding to the first transmission path of the first communication interface, and a communication processing unit 28 corresponding to the second transmission path of the second communication interface.

[0040] The video receiving unit 27 receives video data transmitted from the controller 100 via the information transmission path 200. The video receiving unit 27 temporarily stores the received video data in, for example, the volatile memory 22 and performs necessary processing on the video data. Note that a buffer memory may be provided within the communication unit 23 or the video receiving unit 27. The video receiving unit 27 transfers the processed video data stored in the volatile memory 22, in other words, display data created in accordance with the specifications of the HUD device 10A, to the display driver 24. This causes the display driver 24 to display video on the display panel 15. The display driver 24 drives the display panel 15 based on the display data read from the volatile memory 22, thereby displaying video on the display panel 15.

[0041] In addition to receiving video data, the video receiving unit 27 may also perform video data conversion processing. The video data conversion processing includes converting video data in a format handled by the controller 100 into data and information in a format handled by the HUD device 10A. The type of video data conversion processing required depends on the format of the video data handled by the controller 100 and the format handled by the HUD device 10A. However, typical video data conversion processing includes, for example, video decoding, resolution conversion, and distortion correction to ensure that the image is displayed without distortion when projected onto the projection area 3 of the windshield 2. Depending on the video data received by the HUD device 10A, conversion of resolution, size, brightness, and the like may be required, and the video data conversion processing includes such conversions. Depending on the video data, corrections such as distortion correction and position correction may be required to produce a suitable image without distortion or misalignment of the virtual image 8. The video data conversion processing includes such corrections. Depending on the system configuration, the controller 100 may also perform the video data conversion processing.

[0042] Furthermore, in the configuration of the first example, processor (MCU) 20 functions as a control unit that controls image forming unit 12. The image forming unit 12 is controlled based on a video signal received from vehicle 1 via video receiving unit 27. As will be described in more detail below, as an example, image forming unit 12 performs local dimming control that controls light source device 13 for each display area of display panel 15. When performing this local dimming control, processor 20 further changes the display state of the image on display panel 15 so that the number of areas in which images are displayed among the multiple display areas is reduced compared to the number of areas in which images are currently being displayed. In other words, it can be said that processor 20 performs local dimming control, including control to change the image display on display panel 15, as needed.

[0043] That is, processor 20 changes the display state of display panel 15 so as to reduce the number of areas in which video is displayed among the multiple display areas by controlling the display of each display area of display panel 15. Furthermore, changes to the display state of display panel 15 include moving the display position of the video within display panel 15, changing the display size of the video, and changing the number of display contents included in the video.

[0044] The communication processing unit 28 receives the vehicle information 4, control information, and other information from the controller 100 via the information transmission path 200. The communication processing unit 28 stores the received vehicle information 4, etc., in, for example, the volatile memory 22, and performs necessary processing. Note that a buffer memory for storing the vehicle information 4, etc., may be provided within the communication unit 23 or the communication processing unit 28. When the vehicle information 4 is to be displayed on the HUD, the communication processing unit 28 transfers the processed vehicle information 4 stored in the volatile memory 22 to the display driver 24. As a result, the display driver 24 causes the display panel 15 to display the vehicle information 4 as an image.

[0045] 5A shows a case where the information to be displayed on the HUD is divided into video data, vehicle information 4, and control information, and transmitted and processed via separate information transmission paths 200. However, the information transmission and processing methods are not limited to this. For example, the vehicle information 4 may also be transmitted and processed as part of the video data via the same information transmission path 200.

[0046] Furthermore, the display driver 24 controls the display panel 15 included in the image forming unit 12 to form an image on the display screen of the display panel 15. In other words, the display panel 15, which is formed of, for example, a liquid crystal display panel, forms an image on the display screen based on the drive signal from the display driver 24. The light source drive unit 25 controls the light source device 13 included in the image forming unit 12 to generate light source light. In other words, the light source device 13 generates light source light based on the drive signal from the light source drive unit 25 and supplies the light source light to the display panel 15.

[0047] [HUD device function block (2)] Fig. 5B is a diagram showing an example of a functional block configuration of the HUD device according to Configuration Example 1. More specifically, Fig. 5B shows a configuration in which an image is generated inside the HUD device 10A, as a second example of the functional block configuration of the HUD device 10A according to Configuration Example 1.

[0048] In the block configuration of the second example shown in FIG. 5B, the communication unit 23 does not include a video receiving unit 27, but instead includes a video processing unit 29 connected to the bus 26. In this respect, the configuration of the second example differs from the configuration of the first example shown in FIG. 5A. The video processing unit 29 generates video data to be displayed based on control by the MCU 20, instructions from the controller 100, vehicle information 4 received by the communication processing unit 28, etc. This video data can also be considered display data for display on the HUD device 10A. The video processing unit 29 stores this video data in, for example, the volatile memory 22. The video processing unit 29 transfers the video data stored in the volatile memory 22 to the display driver 24. As a result, the display driver 24 displays the video on the display panel 15. Note that the video processing unit 29 may also include a memory for storing the video data.

[0049] In the configuration of the second example, the processor 20, which is the same as the configuration of the first example, functions as a control unit that controls the image forming unit 12 based on information from the vehicle. When executing local dimming control, the processor 20 changes the display state of the image on the display panel 15 so as to reduce the number of areas in which images are displayed among the multiple display areas. It can also be said that the processor 20 executes local dimming control that includes control of changing the image display on the display panel 15. Note that other block configurations in the second example of configuration example 1 are similar to those in the first example, and therefore description thereof will be omitted. Furthermore, the controller 100 of the vehicle 1 may control the HUD device 10A instead of the processor 20.

[0050] [Display device function block (1)] Fig. 6A is a diagram showing an example of a functional block configuration of a display device according to Configuration Example 2. More specifically, Fig. 6A shows, as a first example of a functional block configuration of a display device 10B according to Configuration Example 2, a configuration in which no video is generated inside the display device 10B.

[0051] The block configuration of Configuration Example 2 shown in Fig. 6A is the same as the block configuration of Configuration Example 1 shown in Fig. 5A, except that the image display device 11 does not include a reflective mirror. That is, in a first example of a display device 10B according to Configuration Example 2 shown in Fig. 6A, the communication unit 23 includes an image receiving unit 27, and this image receiving unit 27 performs necessary processing on image data received from the controller 100. The other block configurations in the first example of Configuration Example 2 are the same as those in Configuration Example 1, and therefore detailed description thereof will be omitted.

[0052] [Display device function block (2)] Fig. 6B is a diagram showing an example of a functional block configuration of a display device according to Configuration Example 2. More specifically, Fig. 6B shows a configuration in which an image is generated inside display device 10B, as a second example of the functional block configuration of display device 10B according to Configuration Example 2.

[0053] In the block configuration of the second example shown in FIG. 6B, the communication unit 23 does not include the video receiving unit 27, but instead includes a video processing unit 29 connected to the bus 26. In this respect, the second example of configuration example 2 differs from the first example shown in FIG. 6A. As described above, the video processing unit 29 generates video data to be displayed (display data) based on the control of the MCU 20, instructions from the controller 100, vehicle information 4 received by the communication processing unit 28, etc., and transfers the generated data to the display driver 24. This causes the display driver 24 to display the video on the display panel 15. Note that the other block configurations in the second example of configuration example 2 are similar to those in the above-mentioned configuration examples, and therefore detailed description thereof will be omitted.

[0054] [Display panel display area] In the HUD device 10A and the display device 10B of the present disclosure, a plurality of display areas, for example, ten display areas, are formed on the display panel 15, and the light source device 13 includes a plurality of light sources corresponding to each display area. Then, by individually controlling the light sources corresponding to each display area, the image display on the display panel 15 can be adjusted for each display area.

[0055] 7 and 8 are plan views illustrating the display area of a display panel, and in the drawings, the direction in which image light is emitted from the display panel is defined as the Z direction. FIG. 7 is a diagram illustrating image forming unit 12 according to Configuration Example 1. FIG. 8 is a plan view illustrating image forming unit 12A according to Configuration Example 2, and FIG. 9 is a side view illustrating the arrangement of image forming unit 12A according to Configuration Example 2.

[0056] An image display device 11 according to configuration example 1 includes one image forming unit 12. As shown in Fig. 7, a light source device 13 of the image forming unit 12 includes a plurality of light sources 131, for example, ten light sources 131A to 131J. These ten light sources 131A to 131J are arranged, for example, in a 2-row by 5-column array. A display panel 15 includes ten display areas A1 to A10 corresponding to the light sources 131A to 131J. In configuration example 1, one display panel 15 is partitioned into ten display areas A1 to A10, and the light sources 131A to 131J are arranged near the center of each of the display areas A1 to A10. In other words, in configuration example 1, the display panel 15 of the image forming unit 12 forms a display surface that is horizontally long in the X direction, and the display surface is made up of 10 display areas A1 to A10 arranged in 2 rows and 5 columns, and light sources 131A to 131J are provided corresponding to each of the display areas A1 to A10.

[0057] The image forming unit 12 can adjust the image display on the display panel 15 for each of the display areas A1 to A10 by individually controlling the corresponding light sources 131A to 131J for each of the display areas A1 to A10 of the display panel 15. In other words, the image forming unit 12 is configured to be able to perform so-called local dimming control for the display areas A1 to A10. In the HUD device 10A according to the first configuration example, the processor 20 performs the local dimming control of the image forming unit 12.

[0058] On the other hand, the image display device 11 according to Configuration Example 2 includes, for example, two image forming sections 12A. It can also be said that the image forming section 12A according to Configuration Example 2 includes two image forming units. As shown in FIGS. 8 and 9, the light source devices 13A of the two image forming sections 12A include a plurality of light sources 131. In this embodiment, each light source device 13A has five light sources, for a total of ten light sources 131A to 131J. The display panel 15 of each image forming section 12A forms ten display areas A1 to A10 corresponding to these ten light sources 131A to 131J.

[0059] In configuration example 2, two image forming units 12A are arranged side by side in the Y direction, and five light sources 131A-131E and 131F-131J of each image forming unit 12A are arranged side by side in the X direction. That is, a total of ten light sources 131A-131J are arranged in two rows and five columns. These ten light sources 131A-131J are provided corresponding to the display areas A1-A10 of display panel 15, respectively.

[0060] In other words, in configuration example 2, the display panels 15 of the two image forming units 12A form a display surface that is horizontally long in the X direction, and the display surface is made up of 10 display areas A1 to A10, which are arranged in a 5 x 2 array. Ten light sources 131A to 131J are arranged corresponding to these 10 display areas A1 to A10.

[0061] The image forming unit 12A is capable of adjusting the image display on the display panel 15 for each of the display areas A1 to A10 by individually controlling the corresponding light sources 131A to 131J for each of the display areas A1 to A10 of the display panel 15. In other words, the image forming unit 12A is configured to be able to perform so-called local dimming control for the display areas A1 to A10. In the display device 10B according to the second configuration example, the processor 20 performs the local dimming control.

[0062] While the configuration in which the light sources 131 corresponding to each of the display areas A1 to A10 are arranged in two rows and five columns has been described as an example, the number and arrangement of the light sources 131 (arrangement of the display areas) are not particularly limited, and the light sources 131 may be arranged in three or more rows. Furthermore, when multiple image forming units 12A are arranged side by side, as in Configuration Example 2, it is preferable that the multiple image forming units 12A are arranged so that they partially overlap. More specifically, as shown in FIG. 9 , when the image forming units 12A are viewed in the Z direction from the display panel 15 side, it is preferable that the display panels 15 and the light sources 131 of adjacent image forming units 12A overlap, and that the light sources 131 are located below (behind) the display panels 15. This allows a display panel 15 having a desired number of display areas to be formed using multiple image forming units 12A.

[0063] 8 and 9 illustrate a display device 10B according to configuration example 2 in which two image forming units 12A are arranged side by side in the Y direction, but the number of image forming units 12A and the arrangement direction thereof are not particularly limited. For example, as shown in FIG. 10, multiple image forming units 12A may be arranged side by side along the X direction. Furthermore, as shown in FIG. 11, multiple image forming units 12A may be arranged side by side along both the X direction and the Y direction.

[0064] [Projection area display image] FIG. 12 is a diagram showing a display image of a projection area in a vehicle equipped with a HUD device or a display device. As described above, image light is projected from the image display device 11 onto the projection area 3 of the windshield 2, thereby forming and displaying a virtual image 8 in the projection area 3 as viewed by the driver 7. In the example shown in FIG. 12, a character image "40 km / h" indicating the vehicle speed is displayed as the virtual image 8 in the projection area 3. In this example, the projection area 3 of the windshield 2 is configured as a screen that is horizontally long in the X direction, and the screen is made up of ten divided areas R1 to R10 in a 5×2 arrangement. The ten divided areas R1 to R10 of the projection area 3 correspond to the ten display areas A1 to A10 of the display panel 15 described above. That is, in this example, the display panel 15 forms a display surface that is horizontally long in the X direction, and the display surface is made up of ten display areas A1 to A10 in a 5×2 arrangement.

[0065] 12, a character image is displayed as a virtual image 8 over the entire divided regions R1 to R10 of the projection region 3. In the example shown in FIG. 12, all of the light sources 131A to 131J corresponding to the display areas A1 to A10 of the display panel 15 are turned on. In other words, this example can also be said to be an example showing a state in which local dimming control of the image forming units 12, 12A is not being executed. Because the virtual image 8, such as a character image, is displayed over the entire projection region 3, that is, because the virtual image 8 is displayed large over a wide range of the projection region 3, the driver 7 can easily view the virtual image 8.

[0066] However, the virtual image 8 does not need to be displayed in all of the divided regions R1 to R10 of the projection region 3. For example, by adjusting the display size and display position of the image on the display panel 15, the virtual image 8 can be displayed in some of the divided regions R1 to R10 of the projection region 3. In the example shown in FIG. 13A, for example, by adjusting the display position of the image on the display panel 15, the virtual image 8, which is the text image "40 km / h", is displayed in the divided regions R1 to R4 and R6 to R9. In the example shown in FIG. 13B, for example, by further adjusting the display position of the image on the display panel 15, the virtual image 8, which is the text image "40 km / h", is displayed in the divided regions R1 to R3 and R6 to R8. In addition, by adjusting the display size as well as the display position of the image on the display panel 15, the number of divided regions in which the virtual image 8 is displayed can be further reduced. However, if the display size of the image is made too small, it becomes difficult for the driver 7 to view the virtual image 8. Therefore, it is preferable to set an adjustment range for the display size of the image in advance.

[0067] In this way, when the virtual image 8 is displayed in a portion of the divided regions R1 to R10, the region where the virtual image 8 is displayed is referred to as the first region Nr1, and the region where the virtual image 8 is not displayed is referred to as the second region Nr2. In the example shown in Fig. 13A, the divided regions R1 to R4 and R6 to R9 correspond to the first region Nr1, and the divided regions R5 and R10 correspond to the second region Nr2. In the example shown in Fig. 13B, the divided regions R1 to R3 and R6 to R8 correspond to the first region Nr1, and the divided regions R4, R5, R9, and R10 correspond to the second region Nr2.

[0068] Note that, for the second region Nr2 where the virtual image 8 is not displayed, no image light is projected or the image light is dark. That is, among the multiple light sources 131 of the light source device 13, the light source 131 corresponding to the second region Nr2 is turned off or the image light from the light source 131 is adjusted to be dark. Alternatively, the processor 20 turns off the light source corresponding to the area where no image is displayed among the multiple display areas or adjusts the brightness or luminance of the light source to be dark. The output of the light source 131 corresponding to the second region Nr2 is reduced compared to the light source 131 corresponding to the first region Nr1. This allows for power saving of the HUD device 10A. In each figure, the area of the second region Nr2 is represented by a gray color.

[0069] FIG. 14 is a diagram showing another example of a projection area onto which a virtual image is projected by a virtual image display device (HUD device 10A or display device 10B). In the example shown in FIG. 14, a portion called black ceramic (referred to as black ceramic portion 2B) is provided on the lower portion (bottom edge) of windshield 2. This black ceramic portion 2B appears black when viewed from the driver 7. This black ceramic portion 2B has a role of protecting the adhesive that bonds windshield 2 to the vehicle body from ultraviolet light from external light. In the example shown in FIG. 14, projection area 3 is formed with ten divided regions R1 to R10, similar to FIG. 12, but differs in that some of the divided regions are arranged to overlap with black ceramic portion 2B. Specifically, the upper half of projection area 3, i.e., divided regions R1 to R5, are arranged above black ceramic portion 2B without overlapping with black ceramic portion 2B. On the other hand, the lower half of projection area 3, i.e., divided regions R6 to R10, are arranged to overlap with black ceramic portion 2B.

[0070] Even when a portion of the divided regions R1 to R10 of the projection region 3 overlaps the black ceramic portion 2B in this way, as shown in FIG. 15A, the text image "40 km / h" and the arrow image can be displayed as the virtual image 8 in the entire projection region 3, i.e., in all of the divided regions AR1 to R10. Also, for example, as shown in FIG. 15B, the text image "40 km / h" and the arrow image can be displayed as the virtual image 8 only in the lower half of the projection region 3 that overlaps the black ceramic portion 2B, i.e., only in the divided regions R6 to R10. Also, as shown in FIG. 15C, the text image "40 km / h" and the arrow image can be displayed as the virtual image 8 only in the upper half of the projection region 3 that does not overlap the black ceramic portion 2B, i.e., only in the divided regions R1 to R5.

[0071] When a bright image, such as white, is displayed as the virtual image 8 on the divided regions R6-R10 that overlap the black ceramic portion 2B, the virtual image 8 is easier to view than when a similar image is displayed as the virtual image 8 on the divided regions R1-R5 that do not overlap the black ceramic portion 2B. For this reason, the brightness of the light sources 131 corresponding to the divided regions R6-R10 that overlap the black ceramic portion 2B is set to half or less, for example, about 50%, of the brightness of the light sources 131 corresponding to the divided regions R1-R5 that do not overlap the black ceramic portion 2B. Therefore, when the virtual image 8 is displayed on the divided regions R6-R10 that overlap the black ceramic portion 2B, the power consumption of the HUD device 10A is reduced compared to when a similar virtual image 8 is displayed on the divided regions R1-R5 that do not overlap the black ceramic portion 2B.

[0072] FIG. 16 shows another example of a projection area onto which image light is projected by a virtual image display device (HUD device or display device). In the example shown in FIG. 16, a plurality of projection areas, for example, two projection areas 3A and 3B, are configured on the windshield 2. In this example, the two projection areas 3A and 3B are arranged close to each other in the left-right direction (X direction) of the vehicle 1. In this example, image light is projected from two image display devices 11 onto the two projection areas 3A and 3B, respectively. In this example, a first image display device 11A and a second image display device 11B are arranged side by side in the left-right direction (X direction) of the vehicle 1 on the dashboard 5. The first image display device 11A projects image light onto the projection area 3A, and the second image display device 11B projects image light onto the projection area 3B. Each of the projection areas 3A and 3B is divided into ten divided areas R1 to R10.

[0073] With this configuration, for example, as shown in FIG. 17A, virtual images 8 such as character images can be individually displayed in both of the two projection areas 3A and 3B. Of course, the two projection areas 3A and 3B can be used as a single horizontally elongated projection area, and a single virtual image 8 such as a character image can be displayed in each of the projection areas 3A and 3B. Alternatively, as shown in FIG. 17B, the virtual image 8 can be displayed in only one of the two projection areas 3A and 3B. The example shown in FIG. 17B illustrates an example in which the display size and display position of the image displayed as the virtual image 8 are changed, the images are aggregated on the display panel 15 of the first image display device 11A, and the second image display device 11B is turned off. In other words, the example shown in FIG. 17B illustrates an example in which the display size and display position of the virtual images 8 displayed in the projection areas 3A and 3B are adjusted, and the virtual images 8 are aggregated and displayed in the projection area 3A.

[0074] In this case, it is not necessary to aggregate all images on the first image display device 11A, and it is also possible to aggregate some of the images displayed on the second image display device 11B on the first image display device 11A. In other words, when the images displayed on the second image display device 11B are aggregated on the first image display device 11A, it is not necessary to turn off all of the light sources 131 of the second image display device 11B, and it is also possible to turn off some of the light sources 131.

[0075] Furthermore, the arrangement of the first image display device 11A and the second image display device 11B is not particularly limited. The first image display device 11A and the second image display device 11B do not necessarily have to be arranged close to each other, and may be arranged with a predetermined distance between them. In other words, the two projection areas 3A, 3B do not necessarily have to be arranged (formed) close to each other, and may be arranged with a predetermined distance between them. For example, a projection area for the driver's seat and a projection area for the passenger's seat may be provided near both ends of the windshield 2 in the left-right direction (X direction) of the vehicle 1.

[0076] Furthermore, the number of image display devices 11 included in the virtual image display device (HUD device 10A or display device 10B) is not particularly limited and may be three or more. For example, in the example shown in FIG. 18 , the virtual image display device (HUD device 10A or display device 10B) includes four image display devices 11, specifically, a first image display device 11A, a second image display device 11B, a third image display device 11C, and a fourth image display device 11D, and four projection areas 3A to 3D are formed within the windshield 2. More specifically, the first image display device 11A, the second image display device 11B, and the third image display device 11C are arranged side by side in the left-right direction (X direction) of the vehicle 1, and the third image display device 11C and the fourth image display device 11D corresponding to the driver's seat are arranged side by side in the up-down direction (Z direction) of the vehicle 1. As a result, the three projection areas 3A to 3C are arranged side by side in the left-right direction of the vehicle 1, and the two projection areas 3C and 3D corresponding to the driver's seat are arranged side by side in the up-down direction of the vehicle 1.

[0077] [Local dimming control] The local dimming control of the image forming units 12, 12A in the virtual image display device 10 will be described in more detail below. Specifically, the processor 20 controls the image forming units 12, 12A to switch between a first mode, which is a normal mode, and a second mode, which is local dimming, based on predetermined conditions. As described above, in the virtual image display device 10, the local dimming control of the image forming units 12, 12A is executed as needed. For example, the operation of the multiple light sources 131 included in the light source device 13 is controlled for each of the display areas A1 to A10 of the display panel 15. When this local dimming control is executed, the state of the virtual image 8 displayed in the projection area 3 naturally changes. Therefore, the local dimming control of the image forming units 12, 12A can also be said to be control that changes the display state of the divided areas R1 to R10 of the projection area 3.

[0078] Here, in the virtual image display device (HUD device or display device) 10, as one of the local dimming controls of the image forming units 12, 12A, control is performed to change the display state of the projection area 3 so that the first area Nr1 in which the virtual image 8 is displayed is reduced, that is, the second area Nr2 in which the virtual image 8 is not displayed is increased, among the divided areas R1 to R10 of the projection area 3. Specifically, by executing the local dimming control, for example, the display state of the projection area 3 shown in FIG. 12 is changed to the display state of the projection area 3 shown in FIG. 13A or 13B.

[0079] In other words, as one type of local dimming control, the virtual image display device 10 performs control to change the display state of the display panel 15 so that the area where an image is displayed (hereinafter referred to as the first area) of the display area A1 to A10 of the display panel 15 is reduced, that is, the area where an image is not displayed (hereinafter referred to as the second area) is increased. For example, in the example shown in Fig. 13A, of the divided areas R1 to R10 of the projection area 3, the divided areas R1 to R4 and R6 to R9 are the first area Nr1, and the divided areas R5 and R10 are the second area Nr2. Therefore, with respect to the display area A1 to A10 of the display panel 15, the display areas A1 to A4 and A6 to A9 corresponding to the divided areas R1 to R4 and R6 to R9 of the projection area 3 correspond to the first area Na1, and the display areas A5 and A10 correspond to the second area Na2.

[0080] FIG. 19 is a flowchart showing an example of a determination process in image formation and display control of the virtual image display device, and FIG. 20 is a diagram for explaining a specific example of the determination process.

[0081] First, in a state where local dimming control of the image forming units 12, 12A is not being executed in the virtual image display device 10, all display areas A1 to A10 of the display panel 15 are in a state where they can display images. That is, all light sources 131A to 131J of the light source device 13 are controlled to be on. In this state, as an example, a virtual image 8 of text images such as vehicle speed is displayed in the entire divided regions R1 to R10 of the projection area 3 (see FIG. 12).

[0082] When the virtual image display device (HUD device 10A or display device 10B) executes local dimming control of the image forming units 12, 12A, it first performs a determination process in step S01, as shown in FIG. 19 . In this determination process, a determination is made for a preset determination item A. In this example, the processor (MCU) 20 performs this determination process. That is, the processor 20 functions as a control unit that performs the determination process. The timing at which the determination process is performed is not particularly limited, and may be, for example, when the vehicle 1 is started. Furthermore, the determination process may be performed at regular intervals while the virtual image display device 10 is operating.

[0083] In the determination process of step S01, as shown in FIG. 20, for example, it is determined whether a predetermined determination condition CA1 or a predetermined determination condition CA2 is satisfied for determination item A. That is, in step S01, it is determined whether determination condition CA2 is satisfied for determination item A. If it is determined that determination condition CA1 is satisfied for determination item A but that determination condition CA2 is not satisfied (step S01: determination result [1]), the process proceeds to step S02, where a first mode, which is a normal mode, is selected as the operation mode of image forming units 12, 12A. On the other hand, if it is determined that determination condition CA2 is satisfied for determination item A (step S01: determination result [2]), the process proceeds to step S03, where a second mode, which is different from the normal mode, is selected as the operation mode of image forming units 12, 12A. This causes local dimming control of image forming units 12, 12A to be performed.

[0084] By executing local dimming control of the image forming units 12 and 12A, necessary information is appropriately displayed while power consumption in the virtual image display device 10 is reduced. As a result, it is possible to reduce battery consumption in the vehicle 1 in which the virtual image display device 10 is installed. Furthermore, it is also possible to suppress a temperature rise in the virtual image display device 10.

[0085] The judgment item A, judgment condition CA1, and judgment condition CA2 in the judgment process of step S01 may be, for example, judgment examples 1 to 7 shown in Fig. 20. However, the judgment item A, judgment condition CA1, and judgment condition CA2 are not limited to these judgment examples and can be set arbitrarily.

[0086] In the determination example 1 of FIG. 20, the determination item A is "remaining battery charge of the vehicle," the determination condition CA1 is "greater than or equal to a threshold," and the determination condition CA2 is "less than a threshold." In this determination example 1, when the remaining battery charge falls below the threshold, i.e., when the remaining battery charge becomes low, local dimming control of the image forming units 12, 12A is executed. The remaining battery charge is acquired by the controller 100 from sensors provided in the vehicle 1, for example, and transmitted to the virtual image display device 10 via the information transmission path 200. The threshold value of the remaining battery charge is a preset value, and the value is not particularly limited and may be determined arbitrarily.

[0087] In determination example 2, determination item A is "vehicle driving mode," determination condition CA2 is "driving mode is power saving mode, ECO mode, or fuel efficiency priority mode," and determination condition CA1 is "other than the above (other than power saving mode, ECO mode, or fuel efficiency priority mode)." In other words, in determination example 2, when the driving mode of vehicle 1 is a first driving mode such as power saving mode, ECO mode, or fuel efficiency priority mode, processor 20 executes local dimming control of image formation units 12, 12A. Note that the first driving mode set as determination condition CA2 is not limited to the above-mentioned power saving mode, ECO mode, or fuel efficiency priority mode.

[0088] In the determination example 3, the determination item A is "user display settings," the determination condition CA1 is "display size and position adjustment not permitted," and the determination condition CA2 is "display size and position adjustment permitted." In the determination example 3, local dimming control of the image forming units 12 and 12A is executed when the display size and position adjustment of the virtual image 8 in the projection area 3, that is, the user has permitted the adjustment of the display size and position of the virtual image 8. As described above, the display size of the virtual image 8 in the projection area 3 can also be rephrased as the display size of the image on the display panel 15. Furthermore, in addition to the above display size, the user may be able to determine the display priority among display content such as alerts, navigation, speed, and time.

[0089] In the fourth determination example, the determination item A is "intensity of incident sunlight," the determination condition CA1 is "less than a threshold," and the determination condition CA2 is "greater than or equal to a threshold." The intensity of incident sunlight is calculated, for example, from the detection result of the illuminance sensor 205. In the fourth determination example, if the intensity of sunlight incident into the vehicle 1 (incident sunlight intensity) is equal to or greater than a threshold, local dimming control of the image forming units 12 and 12A is executed. In other words, if there is a concern that the temperature of the HUD device 10A, particularly the display panel 15, may rise above a predetermined temperature due to the incidence of sunlight into the vehicle 1, local dimming control of the image forming units 12 and 12A is executed. The threshold in the fourth determination example is not particularly limited and may be determined as appropriate. Although not shown, the HUD device 10A may be provided with a sensor such as a sunlight sensor, and the intensity of incident sunlight may be calculated from the detection result of the sunlight sensor.

[0090] Determination item A in determination example 5 is "ambient temperature of HUD device / display device," determination condition CA1 is "less than threshold," and determination condition CA2 is "equal to or greater than threshold." In the determination process of determination example 5, when the temperature near the HUD device / display device, more specifically, the ambient temperature of image display device 11, is equal to or greater than a preset temperature (threshold), local dimming control of image formation units 12, 12A is executed. The ambient temperature of image display device 11 (ambient temperature of HUD device / display device) may be detected, for example, by a temperature sensor provided near image display device 11 inside vehicle 1. The threshold in determination example 5 is not particularly limited and may be set as appropriate.

[0091] In Determination Example 6, Determination Item A is "Failure in the display area of the HUD device / display device," Determination Condition CA1 is "All display areas are displayable," and Determination Condition CA2 is "A specific display area cannot be displayed." In the determination process of Determination Example 6, if there is a failure in any of the display areas A1 to A10 of display panel 15, local dimming control of image formation units 12, 12A is executed. The failure of a display area here refers to a state in which an image cannot be displayed in the display area of display panel 15, and includes not only a failure of display panel 15 itself but also, for example, a failure of light source 131 corresponding to each display area.

[0092] The determination item A of the determination example 7 is "comparison of power consumption of HUD device / display device," the determination condition CA2 is "when the display power of the HUD device / display device is the highest among the display devices of the vehicle," and the determination condition CA1 is "other than the above (when there is a display device with a display power higher than that of the HUD device / display device)." In the determination process of the determination example 7, when the display power (for example, the power consumed to display an image by the image forming units 12, 12A) of the virtual image display device 10 is the highest among the display devices (devices equipped with various monitors) installed in the vehicle 1, local dimming control of the image forming units 12, 12A is executed. This makes it possible to more effectively suppress the consumption of the battery of the vehicle 1 equipped with the virtual image display device 10. Note that the display device here refers to a device equipped with various monitors (displays), and examples include a car navigation device, a rearview mirror monitor, and a monitor for a rear seat.

[0093] Next, local dimming control of the image forming units 12, 12A by the virtual image display device (HUD device 10A or display device 10B) will be described in more detail with reference to Fig. 21, Fig. 22A, and Fig. 22B. Fig. 21 is a flowchart showing an example of local dimming control of the image forming units. Figs. 22A and 22B are diagrams explaining a specific example of local dimming control of the image forming units.

[0094] As described above, in the determination process, when it is determined that the determination for determination item A satisfies determination condition CA2 (step S01: determination result [2]) and local dimming control of image forming units 12, 12A is started, a determination is first made for preset determination item B in step S011, as shown in FIG. 21. In step S011, as shown in an example in FIG. 22A, it is determined whether the determination item B satisfies preset determination condition CB1 or determination condition CB2. However, determination item B and determination conditions CB1, CB2 are not limited to determination example 1 shown in FIG. 22A and can be set arbitrarily.

[0095] The determination item B in determination example 1 of FIG. 22A is "comparison between the number An of backlight (light source) lit areas and the number Bn of areas required for display". Specifically, in this determination example 1, among the plurality of display areas A1 to A10 of the display panel 15, the number of areas (lit area number An) where the light source 131 as the backlight is currently lit is compared with the number of areas (required area number Bn) required to display a predetermined video without changing the display size. The determination condition CB1 in determination example 1 is "An ≧ Bn", and the determination condition CB2 is "An < Bn".

[0096] And when the determination condition CB1 is satisfied for the determination item B (step S011: determination result [1]), it proceeds to step S012, and a determination for a preset determination item C is made. In step S012, as shown by an example in FIG. 22B, for the determination item C, it is determined which of the preset determination conditions CC1 or determination condition CC2 is satisfied. However, the determination item C and the determination conditions CC1, CC2 are not limited to determination example 1 shown in FIG. 22B and can be set arbitrarily.

[0097] The determination item C in determination example 1 of FIG. 22B is "Can the reduction of the backlight lit area (corresponding to the first area Na1) be achieved by moving the display content within the display area?" In this determination, specifically, by moving the position of the predetermined video (display content) displayed on the display panel 15, it is determined whether the number of areas (the first area Na1) where the light source 131 needs to be lit to display the predetermined video among the plurality of display areas A1 to A10 can be reduced. That is, in this determination, by moving the position of the predetermined video displayed on the display panel 15, it is determined whether the number of areas (the second area Na2) where the video is not displayed and the light source 131 can be turned off among the plurality of display areas A1 to A10 can be increased compared to the current situation. In other words, the determination item C determines whether the number of the first regions Nr1 in the projection region 3 can be reduced and the number of the second regions Nr2 can be increased by moving the position of the virtual image 8.

[0098] 22B, the determination condition CC1 is "reducible," which means that the number of first areas Na1 can be reduced by moving the position of the display content on the display panel 15. On the other hand, the determination condition CC2 is "not reducible," which means that the number of first areas Na1 cannot be reduced even if the position of the display content on the display panel 15 is moved.

[0099] Then, in step S012, if it is determined that the determination condition CC1 "reducible" is satisfied (step S012: determination result [1]), the process proceeds to step S013, where the image (display content) displayed on the display panel 15 is moved so that the number of first areas Na1 decreases and the number of second areas Na2 increases. After that, in step S014, the light sources 131 corresponding to the display areas (first areas Na1) necessary for displaying the predetermined image are turned on. That is, some or all of the light sources 131 corresponding to the display areas (second areas Na2) not necessary for displaying the predetermined image are turned off, or the brightness or luminance of the light sources is adjusted.

[0100] On the other hand, if it is determined in step S012 that the judgment condition CC2, "reduction not possible," is satisfied (step S012: judgment result [2]), the process proceeds to step S014, where the light source 131 corresponding to the first area Na1 is turned on. In other words, if the second area Na2 exists, the light source 131 corresponding to the second area Na2 is turned off.

[0101] The control flow from step S011 to step S012 will be described in more detail with reference to FIGS. 23A to 23C. FIGS. 23A to 23C are diagrams showing an example of the display state of the display panel. As shown in FIG. 23A, it is assumed that light sources 131 corresponding to all display areas A1 to A10 of display panel 15 are lit, and a text image 80 indicating the vehicle speed ("40 km / h") is displayed as a predetermined image in display areas A1 to A4 and A6 to A9. In this display state, of the display areas A1 to A10 of display panel 15, eight display areas A1 to A4 and A6 to A9 correspond to the first area Na1, and two display areas A5 and A10 correspond to the second area Na2.

[0102] Here, for example, assume that at least six display areas are required to display a predetermined image, that is, a character image 80, on the display panel 15. Currently, the character image 80 is displayed using eight display areas A1 to A4, A6 to A9. Therefore, when local dimming control of the image forming units 12, 12A is executed, the character image 80 is moved, for example, to the left in the figure, as shown in FIG. 23B, and displayed in six display areas A1 to A3, A6 to A8. In this display state, of the display areas A1 to A10, the display areas A1 to A3, A6 to A8 correspond to the first area Na1, and the display areas A4, A5, A9, and A10 correspond to the second area Na2.

[0103] That is, when local dimming control is executed, the display state of the display panel 15 is changed so that the number of first areas Na1 in which images are displayed among the plurality of display areas A1 to A10 is reduced. Then, for the display areas A4, A5, A9, and A10 corresponding to the second area Na2, the corresponding light sources 131 are turned off. This makes it possible to appropriately display necessary information on the display panel 15 while suppressing the power consumption of the virtual image display device 10.

[0104] In this example, the light sources 131 corresponding to the display area corresponding to the second area Na2 are turned off, but it is also possible to weaken the output of the corresponding light sources 131. In addition, in this example, the output of the corresponding light sources 131 is adjusted in two stages, but it may also be adjusted in multiple stages.

[0105] 23A, assume that at least eight display areas are required to display character image 80. In this case, character image 80 is currently displayed in eight display areas A1 to A4 and A6 to A9, so when local dimming control of image forming units 12 and 12A is executed, character image 80 does not move, but light sources 131 corresponding to display areas A5 and A10, which correspond to second area Na2, are turned off, as shown in FIG.

[0106] 24A, assume that light sources 131 corresponding to all display areas A1 to A10 of display panel 15 are turned on, clock image 81 is displayed as a predetermined image in display areas A1 to A3 and A6 to A8, and road sign image 82 is displayed in display areas A4 to A5 and A9 to A10. In this display state, all display areas A1 to A10 of display panel 15 correspond to first area Na1.

[0107] Here, it is assumed that at least two display areas are required to display clock image 81. Furthermore, it is assumed that at least four display areas are required to display road sign image 82. Clock image 81 is currently displayed in six display areas A1 to A3 and A6 to A8. Therefore, when local dimming control of image forming units 12 and 12A is executed, clock image 81 is moved, for example, in the upper left direction in the figure as shown in FIG. 24B, and is displayed in two display areas A1 and A2. Note that the position to which clock image 81 is moved is not limited to display areas A1 and A2.

[0108] On the other hand, since the road sign images 82 are displayed in the minimum four display areas A4-A5 and A9-A10, the display state is maintained as is even when local dimming control is executed. As a result, of the display areas A1-A10, the display areas A1-A2, A4-A5, and A9-A10 correspond to the first area Na1, and the display areas A3 and A6-A8 correspond to the second area Na2.

[0109] In this example, when local dimming control is executed, the display state of the display panel 15 is changed so that the number of first areas Na1 in which images are displayed among the plurality of display areas A1 to A10 is reduced. Then, for the display areas A3, A6 to A8 corresponding to the second area Na2, the corresponding light sources 131 are turned off. This makes it possible to reduce the power consumption of the virtual image display device 10.

[0110] 21, if the judgment condition CB2 is satisfied for the judgment item B in step S011 (step S011: judgment result [2]), the process proceeds to step S015. For example, if a malfunction occurs in some of the display areas A1 to A10 and the number of lit areas An is less than the number of required areas Bn (step S011: judgment result [2]), the process proceeds to step S015.

[0111] In step S015, it is determined whether the display content of display panel 15 is legible when reduced. More specifically, when the image (display content) is reduced and a desired image (display content) is displayed on display panel 15 using a display area that can normally display the image, without using a display area that cannot display the image, it is determined whether the reduced image is legible to the driver, etc. As an example, if an adjustment range for the display size of the image (display content) is set in advance, it is determined whether the display size of the reduced image is within that adjustment range. If the reduced image is within the preset adjustment range, it is determined that the reduced image is legible to the driver, etc. In other words, a change in the display state of display panel 15 includes a change in the display size of the image.

[0112] If it is determined that the reduced image (display content) is legible by the driver or the like (step S015: Yes), the image is reduced in step S016, and then the process proceeds to step S014, where the light sources 131 corresponding to the display areas required for display are turned on. In other words, the image (display content) is displayed on the display panel 15 using only the display areas that are operating normally.

[0113] On the other hand, if it is determined that the reduced image is unreadable to the driver or the like (step S015: No), the process proceeds to step S017, where, if multiple display contents are displayed on the display panel 15, some of them are reduced. For example, the user may set display priorities (priority levels) for the multiple display contents in advance, and the display contents are reduced as necessary in order of decreasing priority. Thereafter, the process proceeds to step S014, where the light sources 131 corresponding to the display areas required for display are turned on. That is, the image (display contents) remaining after the process of step S017 are displayed on the display panel 15 using only the display area in which the image can be displayed normally.

[0114] 25A to 25C, the process flow from step S011 to step S015 will be described in more detail. For example, as shown in Fig. 25A, assume that text images 80 indicating vehicle speeds are displayed as predetermined images in six display areas A1 to A3, A6 to A8, and road sign images 83 are displayed in four display areas A4 to A5, A9 to A10. Also assume that in this display state, display areas A1 to A2, A6 to A7 become unable to display images due to a malfunction or the like.

[0115] In this case, if the character image 80 and the image 83 are reduced in size and displayed in the display areas A3 to A5 and A8 to A10 that are operating normally, it is determined whether the driver or the like can read the character image 80 and the image 83.

[0116] If it is determined that the driver or the like can read the character images 80 and 83 even after reducing the size of the character images 80 and the images 83, the character images 80 and the images 83 are reduced, and the reduced character images 80 and the images 83 are displayed in the display areas A3 to A5 and A8 to A10 that are operating normally. As an example, as shown in FIG. 25B , the reduced character image 80 is moved and displayed in the display areas A3 to A4 and A8 to A9, and the reduced image 83 is moved and displayed in the display areas A5 and A10. Such changes in the display state of the display panel 15 are also considered to be included in the local dimming control.

[0117] As a result, even if an image cannot be displayed on a portion of display panel 15, the desired image (display content) can be appropriately displayed on display panel 15 so that the driver or the like can read it. Furthermore, if an image cannot be displayed in a portion of the display area due to a malfunction of display panel 15 and light source 131 is lit, light source 131 corresponding to the area in which the image cannot be displayed is turned off, thereby reducing power consumption.

[0118] On the other hand, if it is determined that reducing the character image 80 and the image 83 will make the character image 80 and the image 83 unreadable to the driver or the like, one of the character image 80 and the image 83 is deleted. Whether the character image 80 or the image 83 is to be deleted is determined, for example, based on a display priority that is set in advance. As an example, it is assumed that the priority of the image 83 of a road sign is higher than the priority of the character image 80 indicating the vehicle speed.

[0119] In this case, as shown in FIG. 25C, the character image 80 indicating the vehicle speed is deleted, and road sign images 83 are displayed in the display areas A3-A4 and A8-A9 that are operating normally. This control of changing the number of display contents of the video (display contents) displayed on the display panel 15 is also included in the local dimming control. The change in the number of display contents is, for example, a reduction in the number of display contents. In this example, the light sources 131 corresponding to the display areas A5 and A10 that are operating normally and do not display the image 83 are turned off. This local dimming control also makes it possible to appropriately display necessary information on the display panel 15 while suppressing the power consumption of the virtual image display device 10.

[0120] 25C, image 83 that was displayed in display areas A4-A5, A9-A10 is moved and displayed in display areas A3-A4, A8-A9 at the center of display panel 15. However, in this example, image 83 does not necessarily have to be moved because display areas A4-A5, A9-A10 before the movement are also areas where light source 131 lights up normally. If image 83 is not moved, it is preferable to turn off light sources 131 that correspond to display areas A3 and A8 where image 83 is not displayed.

[0121] As described above, in the present disclosure, when local dimming control is performed, the display state of the display panel 15 is changed so that the number of first areas Na1 in which images are displayed among the multiple display areas is reduced, thereby making it possible to reduce the power consumption of the virtual image display device 10 while appropriately displaying the necessary information (display content) on the display panel 15.

[0122] In the local dimming control in the above embodiment, the light sources 131 serving as backlights are turned off for all of the second areas Na2 in which no video is displayed among the plurality of display areas. However, the number of areas for which the light sources 131 are to be turned off may be determined when local dimming control is initiated. For example, in the flow shown in FIG. 21 , a step may be provided prior to step S011 to determine the number of areas for which video display is to be turned off among the plurality of display areas A1 to A10 of the display panel 15, depending on the power status of the vehicle 1. In this step, the number of areas for which the light sources 131 serving as backlights corresponding to the plurality of display areas A1 to A10 are to be turned off is determined. In this case, the display state of the display panel 15 is appropriately adjusted so that the light sources 131 for the determined number of areas are ultimately turned off.

[0123] The power status of the vehicle 1 is determined based on, for example, the remaining battery charge and the amount of power used. The relationship between the power status of the vehicle 1 and the number of areas in which the video display is turned off is set in advance. For example, it is preferable that the number of areas in which the video display is turned off is set to a larger number as the remaining battery charge of the vehicle 1 decreases, and also that the number is set to a larger number as the amount of power used by the vehicle 1 increases.

[0124] Furthermore, in the above-described embodiment, the local dimming control of the image forming unit 12 was described using the virtual image display device (HUD device or display device) shown in Figures 7, 8, etc. as an example, but the above-described local dimming control can also be performed with the configuration of the virtual image display device shown in Figures 14, 16, and 18, for example.

[0125] 14, when local dimming control is performed to adjust the display size and display position of the image (display content) displayed on display panel 15, it is preferable to concentrate virtual image 8 in divided regions R6 to R10 that overlap black ceramic portion 2B. In this case, too, it is preferable to turn off light source 131 for the display areas of display panel 15 corresponding to divided regions R1 to R5 where virtual image 8 is not displayed (corresponding to second area Na2).

[0126] As described above, the brightness of light sources 131 corresponding to divided regions R6 to R10 that overlap black ceramic portion 2B is set to about 50% of the brightness of light sources 131 corresponding to divided regions R1 to R5 that do not overlap black ceramic portion 2B. Therefore, by concentrating virtual images 8 in divided regions R6 to R10 that overlap black ceramic portion 2B, it is possible to reduce power consumption of virtual image display device 10.

[0127] The technology of the present disclosure has been specifically described above based on the embodiments, but the technology of the present disclosure is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit of the invention. Except for essential components, the above-described embodiments can include additions, deletions, and substitutions of components. Unless otherwise specified, each component may be singular or plural. Combinations of the embodiments are also possible.

[0128] Furthermore, by using the technology according to the above-described embodiment, it is possible to appropriately display necessary information while reducing the power consumption of the virtual image display device 10. This makes it possible to provide an information display device (head-up display device) that contributes to safe driving, etc., and thus to reduce traffic accidents. Furthermore, it is possible to contribute to "3. Good health and well-being" of the Sustainable Development Goals (SDGs) advocated by the United Nations. [Explanation of symbols]

[0129] 1...vehicle, 2...windshield, 2B...black ceramic part, 3...projection area, 4...vehicle information, 5...dashboard, 6...opening, 7...driver, 8...virtual image, 10...virtual image display device, 10A...HUD device, 10B...display device, 11...image display device, 12...image formation unit, 13...light source device, 14...optical component, 15...display panel, 16...drive mechanism, 20...processor (MCU), 131...light source, 300...in-vehicle system

Claims

1. A virtual image display device that displays a virtual image by projecting image light onto a projection area of a windshield of a vehicle, an image forming section including a light source device having a plurality of light sources and a display panel on which an image is displayed and which forms a plurality of display areas corresponding to the light sources; a processor that controls the image forming unit, The processor: changing a display state of the display panel so that the number of areas in which the video is displayed is reduced among the plurality of display areas by controlling the display of each of the display areas; Virtual image display device.

2. The virtual image display device according to claim 1, The processor: turning off the light sources corresponding to areas among the plurality of display areas where the video is not displayed; Virtual image display device.

3. The virtual image display device according to claim 1, The change in the display state of the display panel includes moving the display position of the image within the display panel. Virtual image display device.

4. The virtual image display device according to claim 1, The change in the display state of the display panel includes a change in the display size of the video. Virtual image display device.

5. The virtual image display device according to claim 1, The change in the display state of the display panel includes a change in the number of display contents included in the video. Virtual image display device.

6. The virtual image display device according to claim 1, the projection area is set to an area including a black ceramic portion formed on the windshield, changing the display state of the display panel includes moving the display position of the image to an area of the display area that corresponds to the projection area on the black ceramic portion; Virtual image display device.

7. The virtual image display device according to claim 1, The processor: performing a determination process to determine whether or not the vehicle satisfies a predetermined determination condition; performing local dimming control for controlling the display of the video for each of the display areas based on the result of the determination process; Virtual image display device.

8. The virtual image display device according to claim 7, The processor: the determination process includes determining a remaining capacity of a battery provided in the vehicle, and executing the local dimming control when it is determined that the remaining capacity of the battery is less than a preset remaining capacity. Virtual image display device.

9. The virtual image display device according to claim 7, The processor: the determination process includes determining a driving mode of the vehicle, and when it is determined that the driving mode is a preset first driving mode, executing the local dimming control. Virtual image display device.

10. The virtual image display device according to claim 7, The processor: As the determination process, it is determined whether or not a change in the display state of the video is permitted by the user, and when it is determined that the change is permitted by the user, the local dimming control is executed. Virtual image display device.

11. The virtual image display device according to claim 7, The processor: the intensity of sunlight incident on the vehicle is determined as the determination process, and when it is determined that the intensity of the sunlight is equal to or greater than a preset intensity, the local dimming control is executed. Virtual image display device.

12. The virtual image display device according to claim 7, The processor: the determination process includes determining an ambient temperature of the image forming unit, and executing the local dimming control when it is determined that the ambient temperature of the image forming unit is equal to or higher than a preset temperature. Virtual image display device.

13. The virtual image display device according to claim 7, The processor: the determination process includes determining whether or not there is a failure in the plurality of display areas, and when it is determined that there is a failure in any of the display areas, executing the local dimming control. Virtual image display device.

14. The virtual image display device according to claim 7, The processor: the determination process includes determining power consumptions of a plurality of display devices provided in the vehicle, and executing the local dimming control when it is determined that the power consumption of the image forming unit is the largest among the plurality of display devices. Virtual image display device.

Images