Display system

Abstract

Provided is a display system comprising: a plurality of display devices that are mounted on a vehicle and project video light; and a control unit that controls the respective display devices. The control unit adjusts the luminance of the display devices according to the situation.

Description

Display system

[0001] The present invention relates to a display system and a vehicle equipped with the display system.

[0002] A display device or virtual image display device is known that projects image light onto the windshield or windshield of a vehicle such as an automobile to display a virtual image, and displays vehicle information such as driving information such as vehicle speed and engine speed, traffic information from navigation, and vehicle information such as fuel level and coolant temperature.

[0003] Japanese Patent Application Publication No. 3-169752

[0004] Display devices are, for example, located on or inside the vehicle's dashboard. Using a display device, the driver can obtain the information necessary for driving without shifting their gaze to the instrument panel, or so-called dashboard, which is integrated into the dashboard. However, considerations regarding the placement, brightness, influence from ambient light, and information display of the display device have not been sufficient.

[0005] The object of the present invention is to provide a more suitable display device, display system, or display technology.

[0006] According to an aspect of the present invention, the following display system is provided. The display system comprises a plurality of display devices mounted on a vehicle that project image light, and a control unit that controls each of the display devices. The control unit adjusts the brightness of the display system according to the situation.

[0007] According to the present invention, a more suitable display system or display technology can be provided. Other problems, configurations, and effects not mentioned above will be clarified by the following description of the embodiments.

[0008] This figure shows an example of an in-vehicle system including a display device. This figure shows an example of a device used to acquire vehicle information. This is a block diagram showing an example of a display device. This figure shows an example of a configuration in which a display device is mounted on a vehicle. This figure shows an example of a configuration in which a display device is mounted on a vehicle. This figure shows an example of a light source structure for a display device. This figure shows an example of a configuration in which multiple display devices are arranged side by side. This figure explains the brightness of an image due to viewing angle characteristics. This figure shows an example of a system configuration. This figure shows an example of a control flow. This figure explains a specific example of brightness adjustment for a display device. This figure explains judgment example 1 in detail. This figure explains judgment example 1 in detail. This figure explains judgment example 2 in detail. This figure explains judgment example 2 in detail. This figure explains judgment example 3 in detail. This figure explains judgment example 3 in detail. This figure explains judgment example 4 in detail. This figure explains judgment example 4 in detail. This figure explains judgment example 5 in detail. This figure explains judgment example 5 in detail.

[0009] Embodiments of the present invention will be described below with reference to the drawings. The embodiments are illustrative examples for explaining the present invention, and have been omitted and simplified as appropriate for clarity of explanation. The present invention can also be implemented in various other forms. Unless otherwise specified, each component may be singular or plural. The position, size, shape, and range of each component shown in the drawings may not represent the actual position, size, shape, and range in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, and range disclosed in the drawings. When there are multiple components that have the same or similar function, they may be described using the same reference numeral with different subscripts. Also, when it is not necessary to distinguish between these multiple components, the subscripts may be omitted in the description.

[0010] In explanations, when describing program-based processing, the focus may sometimes be on the program, functions, or processing units. However, the main hardware component is the processor, or a controller, device, computer, or system composed of such a processor. The computer, using its processor, executes processing according to the program read into memory, utilizing resources such as memory and communication interfaces as appropriate. This realizes the specified functions and processing units. The processor is composed of semiconductor devices such as a CPU / MPU or GPU. Processing is not limited to software program processing; it can also be implemented using dedicated circuits. Applicable dedicated circuits include FPGAs, ASICs, CPLDs, etc.

[0011] The program may be pre-installed as data on the target computer, or it may be distributed as data to the target computer from the program source. The program source may be a program distribution server on a communication network, or a non-transient computer-readable storage medium, such as a memory card or disk. The program may consist of multiple modules. The computer system may consist of multiple devices. The computer system may consist of a client-server system, a cloud computing system, an IoT system, etc. Various types of data and information are composed of structures such as tables and lists, but are not limited to these. Representations such as identification information, identifiers, IDs, names, and numbers are interchangeable.

[0012] Figure 1 shows an example configuration of an in-vehicle system including a display device. With respect to the vehicle or ride 2 and the driver, the horizontal direction X is the left-right direction, the lateral direction of the vehicle or ride 2, or the width direction of the vehicle or ride 2; the vertical direction Z is the up-down direction, or vertical direction of the vehicle; and the horizontal direction Y, which is perpendicular to the lateral direction of the vehicle or ride 2, is the front-rear direction of the vehicle or ride 2, or the direction of travel of the vehicle. In the example in Figure 1, the direction in which the vehicle travels is set to be the negative direction in the Y-axis direction. The display device 1 may also be called a virtual image display device. The following explanation will use the name "display device". The vehicle or ride 2 is typically an automobile or a truck, but is not limited to these, and may also be a railway vehicle or an aircraft. The following explanation will use the name "vehicle".

[0013] The display device 1 acquires vehicle information 4 from cameras and various sensors installed in various parts of the vehicle 2. The various sensors, for example, detect various events that occur in the vehicle 2 and periodically detect the values ​​of various parameters related to driving conditions. It can also acquire road information from the navigation device 6 (car navigation system), external devices 400, terminal devices 410 (e.g., mobile terminals), and GPS (Global Positioning System) information. The GPS may be installed in the vehicle 2, or it may be installed in the external devices 400 or terminal devices 410.

[0014] Vehicle information 4 includes, for example, vehicle 2's speed information, gear information, steering angle information, lamp illumination information, ambient light information, distance information, infrared information, engine ON / OFF information, camera image information, accelerometer / gyro information, GPS (Global Positioning System) information, navigation information, vehicle-to-vehicle communication information, and vehicle-to-infrastructure communication information. Camera image information includes in-vehicle camera image information and exterior camera image information. GPS information includes latitude and longitude as well as current time information. Vehicle information 4 also includes input information from the driver.

[0015] The display device 1 is connected to the controller 100 of the vehicle 2 via an information transmission path, and the display device 1 and the controller 100 are able to communicate with each other. The controller 100 of the vehicle 2 is an ECU (Electronic Control Unit). The display device 1 and the controller 100 of the vehicle 2 communicate via the information transmission path using, for example, a CAN (Controller Area Network) or LIN (Local Interconnect Network) interface. Alternatively, the display device 1 and the controller 100 of the vehicle 2 may communicate via the information transmission path using an in-vehicle Ethernet or the like. Other connection configurations may also be adopted. For example, when transmitting all information, including video information, through a single information transmission path, the connection between the controller 100 on the vehicle 2 side (source of video information, etc.) and the display device 1 (in other words, the connection configuration of the information transmission path) may be FPD-Link III, GMSL (Gigabit Multimedia Serial Link), etc.

[0016] The in-vehicle system is configured such that the controller 100 controls the vehicle 2 based on data input and output and is connected to the display device 1. The in-vehicle system can communicate with the outside of the vehicle 2 via a communication device or network. Examples of communication with the outside of the vehicle 2 include direct communication and indirect communication. Direct communication is used internationally as ITS (Intelligent Transport System) communication, while indirect communication is performed, for example, via a server to an external device 400 or terminal device 410. The in-vehicle system can send and receive data or information to, for example, a server 700 connected to the network 500 via a relay station 600 on the network 500. The in-vehicle system may also communicate with infrastructure such as external devices and terminals installed on the road on which the vehicle 2 travels.

[0017] Figure 2 shows an example of a device used to acquire vehicle information. As shown in Figure 2, vehicle information 4 is acquired using devices such as a camera and various sensors connected to the controller 100 or control device 100. Note that the various devices in Figure 2 can be deleted, other types of devices added, or replaced with other types of devices as appropriate. Also, as an example, the controller 100 of the vehicle 2 may also have the function of controlling the display device 1.

[0018] The vehicle speed sensor 901 detects the speed of the vehicle 2 and is used to generate speed information as a result of the detection. The shift position sensor 902 detects the current gear and is used to generate gear information as a result of the detection. The steering angle sensor 903 detects the current steering angle and is used to generate steering angle information as a result of the detection. The headlight sensor 904 detects whether the headlights are ON or OFF and is used to generate lamp illumination information as a result of the detection.

[0019] The illuminance sensor 905 and the chromaticity sensor 906 detect ambient light from the vehicle 2 and are used to generate ambient light information as detection results. The distance measuring sensor 907 detects the distance between the vehicle 2 and an external object, or the distance between external objects, and is used to generate distance information as detection results. The infrared sensor 908 detects the presence and distance of objects in the vicinity of the vehicle 2 and is used to generate infrared information as detection results. The engine start sensor 909 detects the ON / OFF status of the engine and is used to generate ON / OFF information as detection results. The acceleration sensor 912 and the gyro sensor 913 detect the acceleration and angular velocity of the vehicle 2 and are used to generate acceleration gyro information representing the attitude and behavior of the vehicle 2.

[0020] The temperature sensor 914 detects the temperature inside and outside the vehicle and is used to generate temperature information as the detection result. For example, if the display device 1 is located inside the dashboard of the vehicle 2, the temperature sensor 914 may be used to detect the temperature inside the dashboard. If a temperature that may affect the operation of the display device 1 is detected, the display device 1 may stop operating. The temperature sensor 914 may also be located in other places that may reach temperatures similar to those inside the dashboard.

[0021] Furthermore, if the display device 1 is installed on the dashboard or elsewhere, the temperature sensor 914 may be used to detect the temperature in the vicinity where the display device 1 is installed. If a temperature is detected that may affect the operation of the display device 1 due to direct sunlight or the like, the display device 1 may stop operating. Here, the temperature sensor 914 may be placed on the dashboard as an example. The temperature sensor 914 may also be placed outside the vehicle, assuming that the temperature near the display device 1 and the temperature outside the vehicle are similar.

[0022] The vehicle-to-infrastructure wireless transceiver 915 generates vehicle-to-infrastructure communication information through vehicle-to-infrastructure communication between the vehicle 2 and roads, signs, signals, etc. The vehicle-to-vehicle wireless transceiver 916 generates vehicle-to-vehicle communication information through vehicle-to-vehicle communication between the vehicle 2 and other surrounding vehicles. The wired wireless communication unit 917 for mobile terminal-to-vehicle communication is a device that acquires information via wired or wireless communication from devices connected to an LTE (Long Term Evolution) network (e.g., Wi-Fi devices). The controller 100 or control device can acquire information transmitted and received on the LTE network via the wired wireless communication unit 917 for mobile terminal-to-vehicle communication.

[0023] The in-vehicle camera 919 and the exterior camera 920 capture images of the interior and exterior of the vehicle and are used to generate in-vehicle and exterior camera image information. Specifically, the in-vehicle camera 919 is, for example, a camera for a Driver Monitoring System (DMS) that captures the driver's posture, eye position, and movement. In this case, by analyzing the captured images, the driver's fatigue level and gaze position can be determined.

[0024] On the other hand, the external camera 920 captures images of the surroundings, such as the front and rear of the vehicle 2. In this case, by analyzing the captured images, it becomes possible to determine the presence or absence of obstacles such as other vehicles or people in the vicinity, buildings and terrain, road surface conditions such as rain, snow, ice, and unevenness, and road signs. The external camera 920 may also include, for example, a drive recorder that records the situation while driving.

[0025] The GPS receiver 921 generates GPS information obtained by receiving GPS signals from GPS satellites. For example, the GPS receiver 921 can obtain the current time, latitude, and longitude. The VICS (Vehicle Information and Communication System, registered trademark) receiver 922 generates VICS information obtained by receiving VICS signals. The GPS receiver 921 and the VICS receiver 922 may be provided as part of a navigation system.

[0026] The voice input device 918 receives the driver's voice and is used to generate voice information. The driver can input operation details via the voice input device 918 by speaking. The vehicle operation switches 911 are used to generate driver operation information for steering wheel switches, etc.

[0027] Furthermore, the video generation unit 910 generates video information based on vehicle information 4 acquired by the controller 100 of the vehicle 2. It can also generate video information based on external information.

[0028] Figure 3 is a block diagram of the display device 1. It is mainly used to control the display of projected images (virtual images) on the display device 1.

[0029] In Figure 3, the display device 1 includes, for example, a control unit 1010, a non-volatile memory 1011, a volatile memory 1012, a storage unit 1013, a display driver 1021, and a light source drive unit 1022, all of which are mounted on a wiring board or the like. The display device 1 also includes a communication unit 1014, a wireless communication unit 1015, a video processing unit 1016, an operation input unit 1017, an external power input unit 1018, a speaker 1019, and a light-emitting indicator 1020.

[0030] The control unit 1010 is specifically a microcontroller unit (MCU), a CPU (Central Processing Unit), etc. Each block other than the control unit 1010 may be mounted within the control unit 1010 as appropriate. Furthermore, the display device 1 is not limited to implementation using the control unit 1010, but may also be implemented using an ECU (Electronic Control Unit) or other semiconductor devices. The configuration shown in Figure 3 may, for example, be a control unit mounted inside the housing of the display device 1, or a control unit mounted outside the housing. Also, the display device 1 can be controlled by a controller in the vehicle 2 or an external device without implementing the control unit 1010 in the display device 1.

[0031] The non-volatile memory 1011 primarily stores programs executed within the control unit 1010, setting parameters used in the processing of each part within the control unit 1010, and predefined audio and video data. The non-volatile memory 1011 may also store information other than programs, such as video, audio, and video.

[0032] The volatile memory 1012 operates by unpacking the program stored in the non-volatile memory 1011. The volatile memory 1012 primarily processes acquired information and various data used in the processing of each part within the control unit 1010 as appropriate.

[0033] The storage unit 1013 stores video data, video data, or audio data for output to the speaker 1019, etc. The video data, video data, or audio data to be stored in the storage unit 1013 may be stored in the storage unit 1013 in advance. Alternatively, the video data, video data, or audio data to be stored in the storage unit 1013 may be received from an external device via the communication unit 1014.

[0034] In Figure 3, the communication unit 1014 transmits and receives information such as vehicle information 4 to and from the controller 100 of the vehicle 2 or various devices such as sensors of the vehicle 2, using a mechanism such as CAN or an in-vehicle Ethernet. The communication unit 1014 may also receive video information using a mechanism such as FPD-Link III or GMSL. The hardware of the communication interface that receives vehicle information 4 and the hardware of the communication interface that receives video information in the communication unit 1014 may be separate or integrated. The communication unit 1014 may also function as the control unit of the display device 1.

[0035] The wireless communication unit 1015 may be configured with a Wi-Fi communication interface, a Bluetooth® communication interface, a mobile communication interface such as 4G or 5G, etc. As shown in Figure 1, the wireless communication unit 1015 may communicate with external devices via a network 500 connected through a router or relay station 600. An example of an external device is a server 700 connected via the network 500. Alternatively, the wireless communication unit 1015 may communicate directly with a terminal device 410, etc. An example of a terminal device 410 is a smartphone, tablet, wireless earphones, headphones, or beacon.

[0036] The video processing unit 1016 may perform distortion correction, conversion, and other processing on the received video information. The video processing unit 1016 may generate video data for the video display unit 200 using acquired vehicle information, external information, etc. Specifically, the distortion correction here corrects the distortion of the video caused by the curvature of the windshield 3 when the video from the display device 1 is projected onto the display area 5, as shown in Figure 1. The video processing unit 1016 may also be implemented by the control unit 1010 reading and executing a program stored in the non-volatile memory 1011 or the volatile memory 1012.

[0037] That is, the video processing unit 1016 processes video data related to the display video projected onto the display area 5 in FIG. 1 or the like based on information acquired from the outside or the vehicle 2. On the other hand, although it is not necessarily required to have the video processing unit 1016, in such a case, the control unit 1010 can process video information from the vehicle 2 or an external terminal or the like via the communication unit 1014. Also, the video information may be processed by the controller 100 of the vehicle 2.

[0038] The operation input unit 1017 is, for example, an operation button, a receiving unit such as a remote controller, or an infrared light receiving unit, and is for inputting a user's operation. The operation input unit 1017 may be used, for example, by a driver to operate the display device 1.

[0039] The external power input unit 1018 inputs power from the outside and supplies the necessary power to each part of the display device 1 in FIG. 3.

[0040] The speaker 1019 emits sound based on the audio data stored in the volatile memory 1012, the non-volatile memory 1011, or the storage unit 1013.

[0041] The light-emitting indicator 1020 emits light by a light-emitting element or the like, and can notify the user of the state of the display device 1 by the light-emitting timing or the light-emitting color of the light-emitting element.

[0042] The display driver 1021 drives each display element (pixel) included in the display panel 11 based on the video data. As a result, the video display unit 200 creates and displays a video for projection onto the display area 5 based on the video data. The display driver 1021 can be configured, for example, by a circuit mounted on a substrate.

[0043] The light source driving unit 1022 drives the light source 20 to generate light source light. Based on the driving from the light source driving unit 1022, the light source 20 generates light source light and supplies it to the display panel 11. The light source 20 is adjusted or controlled using the light source driving unit 1022, which is a driver used for driving the light source, based on the vehicle information 4 received via the communication unit 1014 or information from a terminal device or the like.

[0044] Furthermore, the display device 1 may protect the display panel 11 based on ambient light information from the illuminance sensor 905. That is, in order to prevent the display panel 11 from being burned out by sunlight, the display device 1 may perform an operation to protect the display panel 11 from sunlight according to the value of the illuminance sensor 905. More specifically, if the intensity of ambient light or sunlight acquired by the illuminance sensor 905 is strong and there is a risk of the display panel 11 being burned out, the brightness of the light source 20 is reduced, and the amount of light from the light source 20 incident on the display panel 11 is suppressed, thereby suppressing the temperature rise of the display panel 11.

[0045] Each component in Figure 3 may be implemented using a dedicated circuit such as an FPGA (Field Programmable Gate Array) as appropriate. In this embodiment, the system has a non-volatile memory 1011, a volatile memory 1012, a storage unit 1013, and a video processing unit 1016, but the above processing may be performed using a single memory.

[0046] Next, the video display unit 200 will be described in detail. Based on video data, the video display unit 200 projects video light from the light source 20 (in other words, light from the light source) onto the display panel 11. The video display unit may also be called a projection-type video display device or a projector. The video display unit 200 comprises a light source 20 and a display panel 11 such as a liquid crystal display (LCD) having video display elements.

[0047] The light source 20 functions as a backlight source for the display panel 11. The light source 20 is configured, for example, using a semiconductor light source element, and generates a predetermined light source and supplies it to the display panel 11. Typically, an LED (Light Emitting Diode) element is used as the semiconductor light source element. The light source 20 may also be configured by arranging multiple light sources. The light source unit (backlight unit) 12, which will be described later, may be configured using the light source 20 or the like.

[0048] The display panel 11 generates and emits modulated video light based on the light source. In other words, the display panel 11 forms and displays an image on the display screen based on video data, and generates and emits video light corresponding to the image based on the light from the light source 20. The video data in this embodiment will be described as video data input from the video processing unit 1016. The display panel 11 forms an image to be projected onto the display area 5 by modulating the light from the light source 20 pixel by pixel according to the video data, and projects it as video light (in other words, projected light).

[0049] Furthermore, the display panel 11 is not limited to a liquid crystal panel; it may also be a screen plate with a diffusion function. As a means of projecting an image onto the screen plate with a diffusion function, a means of projecting an image from a DMD (Digital Micromirror Device) or a liquid crystal panel in combination with a projection lens may be used, or a means of using a micro-electromechanical system may be used.

[0050] Figures 4 and 5 show examples of configurations in which the display device 1 is mounted on a vehicle 2. Figure 4 shows an example of mounting the display device 1 on a passenger car. Passenger cars include sports cars, sedans, SUVs (Sport Utility Vehicles), and minivans, where the angle of the windshield 3 is 20° to 45° with respect to the Y-axis (the longitudinal direction or direction of travel of the vehicle 2). Figure 5 shows an example of mounting the display device 1 on some passenger cars and commercial vehicles, in other words, the windshield or windshield 3 in Figure 5 is in an upright position. Specifically, these include light super-height wagons, trucks, and buses, where the angle of the windshield 3 is 45° to 90° with respect to the Y-axis (the longitudinal direction or direction of travel of the vehicle 2). As shown in Figures 4 and 5, the display device 1 is located on the dashboard 7 of the vehicle 2. The display device 1 may also be implemented so as to be embedded within the dashboard 7. The dashboard 7 also includes an instrument panel, for example, a meter cluster in front of the steering wheel.

[0051] As shown in Figures 4 and 5, the image light 13 in Figure 4 is emitted toward the driver, and the image light 13 in Figure 5 is emitted toward the windshield 3. The image light 13 emitted from the display device 1 is reflected when it is irradiated onto the windshield or windshield 3. The reflected image light 13 is incident on the driver's viewpoint 14. From the driver's viewpoint 14, a virtual image 10 corresponding to the image light 13 is formed and visible at a position visible through the display area 5 (Figure 1) of the display device 1 corresponding to the irradiation area of ​​the image light 13. In this embodiment, the projection of image light onto the display area 5 of the windshield 3 is described, but the projection unit that projects the image light may be a projection member other than the windshield 3.

[0052] Figure 6 shows the video display unit 200 of the display device 1. The light source unit 12 may also be called the backlight unit. The light source unit 12 includes a light source 20, a reflective mirror 21, a polarization conversion element 22, and a light guide unit 23, and may also include a diffuser plate 24. The reflective mirror 21 is used to reflect light from the light source 20 and adjust it to parallel light. The reflective surface of the reflective mirror 21 is a parabolic surface and may be asymmetrical with respect to the optical axis of the light emitted from the light source 20. The reflective mirror 21 may also be positioned eccentrically with respect to the light source 20. The reflective mirror 21 may also be called a reflector.

[0053] The polarization conversion element 22 is composed of a polarizing beam splitter (PBS) and a phase difference film (1 / 2λ). It separates incident light into S-polarized and P-polarized light, and then uses the phase difference film (1 / 2λ) to polarize either the separated S-polarized or P-polarized light, so that the randomly polarized light incident on the polarization conversion element 22 is emitted as linearly polarized light.

[0054] The light guide section 23 may also be called an optical transmission section. The light guide section 23 is configured to adjust the angle of incidence of light rays to the display panel 11, and in this example, it is configured using an optical reflecting section 23a having a prism shape (a jagged shape). The light guide section 23 may also be a prism sheet as an example. In this example, the light rays incident on the optical reflecting section 23a of the light guide section 23 are adjusted to a predetermined light distribution and reflected toward the display panel 11. The distribution of light incident on the display panel 11 can be adjusted by the shape of the reflective surface of the optical reflecting section 23a, the inclination of the reflective surface, the surface roughness, etc. In this structure, the optical axis of the light source 20 and the optical axis of the light incident on the display panel 11 are parallel or approximately parallel.

[0055] The light guide 23 is, for example, a resin member having a prism shape, and the prism-shaped portion that becomes the reflective surface is coated with an Al reflective film or the like. The light reflective portion 23a of the light guide 23 may be configured to have multiple inclinations on one surface in order to achieve more precise adjustment of reflected light. Furthermore, the reflective surface may be composed of multiple or multifaceted surfaces, or it may be composed of curved surfaces. When a large number of reflective surfaces and connecting surfaces are alternately formed in a sawtooth pattern on the light reflective portion 23a, the light incident on the light guide 23 is reflected on each reflective surface and directed toward the display panel 11, and further adjusted to a predetermined light distribution characteristic via the diffuser plate 24 before incident on the display panel 11. The diffuser plate 24 uniformly disperses the incident light from the light guide 23. The diffuser plate 24 has the effect of improving the brightness uniformity within the virtual image plane.

[0056] Furthermore, the video display unit 200 may have a configuration other than that shown in Figure 6, and may, for example, include a light source, an illumination optical system, a PBS or polarization separation element, and a reflective liquid crystal panel or LCOS.

[0057] As shown in Figures 7A and 7B, for example, multiple display devices (1A, 1B, 1C) may be arranged, and each display device (1A, 1B, 1C) may display an image. Here, each display device (1A, 1B, 1C) should be arranged so as to project image light toward a projection member such as a windshield 3. For example, each display device (1A, 1B, 1C) may be arranged in the vehicle width direction (X direction) in front of the driver's seat. For example, each display device (1A, 1B, 1C) may be arranged in front of the driver's seat, along the vehicle width direction (X direction) when viewed from the vertical direction (Z direction) of the vehicle. Also, for example, each display device (1A, 1B, 1C) may be placed on or inside the dashboard 7 in front of the driver's seat. Furthermore, if the display devices (1A, 1B, 1C) are positioned inside the dashboard 7, an opening may be formed in the upper part of the dashboard 7 through which the video light emitted by the display devices (1A, 1B, 1C) can pass. By reflecting the video light from multiple display devices (1A, 1B, 1C) with a projection member such as the windshield 3, it becomes possible to display information over a wide area.

[0058] However, each display device (1A, 1B, 1C) has its own viewing angle characteristics. Therefore, there is a problem in that the brightness of the image seen differs depending on the direction from which the image is viewed. For example, in the situation shown in Figure 7B, the brightness of the image is highest when viewed from the direction of the solid line. Furthermore, the larger the angle formed between the direction of the solid line and the line of sight (the direction of the dashed line), the lower the brightness of the image seen.

[0059] Therefore, this embodiment will be described using three display devices. In this example, the driver 71 will see the image from the brightest display device C (1C), the next brightest display device B (1B), and the next brightest display device A (1A). Thus, when multiple display devices (1A, 1B, 1C) are arranged, an example of a technique to improve visibility by appropriately adjusting the brightness of the images on each display device (1A, 1B, 1C) will be described.

[0060] For example, display device C (1C) is positioned to the right of the center of vehicle 2 in the vehicle width direction (X direction). Display device B (1B) is positioned in the center of vehicle 2 in the vehicle width direction (X direction). Display device A (1A) is positioned to the left of the center of vehicle 2 in the vehicle width direction (X direction).

[0061] Referring to Figure 8, an example of a system configuration will first be described. This system S (display system) includes, as an example, a plurality of display devices (in Figure 8, display device A (1A), display device B (1B), and display device C (1C)) and a control unit 81. Here, similar to the above, display device A (1A) may be positioned in front of the driver's seat and to the left of the center of the vehicle 2 in the vehicle width direction (X direction), display device B (1B) may be positioned in front of the driver's seat and in the center of the vehicle 2 in the vehicle width direction (X direction), and display device C (1C) may be positioned in front of the driver's seat and to the right of the center of the vehicle 2 in the vehicle width direction (X direction).

[0062] The control unit 81 is configured to control each of the display devices (in Figure 8, display device A (1A), display device B (1B), and display device C (1C)). Here, the control unit 81 may be configured using a processor mounted in the vehicle 2, such as an ECU. Alternatively, the control unit 81 may be configured using all or some of the processors of each display device (control unit 1010, such as an MCU). Furthermore, the control unit 81 may be configured using other processors mounted in the vehicle 2. Also, the control unit 81 may be configured using multiple of these processors. Communication between the control unit 81 and each of the display devices (1A, 1B, 1C) is achieved by CAN communication, but other communication methods such as in-vehicle Ethernet may also be used.

[0063] Furthermore, the control unit 81 may be directly or indirectly connected to components mounted on the vehicle 2 (for example, various sensors mounted on the vehicle 2, communication equipment mounted on the vehicle 2, etc.), acquire information (for example, vehicle information 4) from the vehicle 2, and control each of the display devices (1A, 1B, 1C).

[0064] Furthermore, the control unit 81 may acquire information from external devices 400, terminal devices 410, etc., and control each display device (1A, 1B, 1C). Here, for example, the control unit 81 may acquire predetermined instruction information from external devices 400, terminal devices 410, etc., and control each display device (1A, 1B, 1C) based on the acquired information. For example, the control unit 81 may acquire information regarding display image settings, such as the size of the display image, from external devices 400, terminal devices 410, etc., and control the display devices (1A, 1B, 1C) to display according to the acquired information. Also, for example, the control unit 81 may acquire selection information for the video content to be displayed from external devices 400, terminal devices 410, etc., and make adjustments to display the content selected by the user of the external devices 400, terminal devices 410, etc.

[0065] The display flow of the display device will be explained with reference to Figure 9. The control unit 81 checks the status of multiple display devices (1A, 1B, 1C) and confirms information such as vehicle information 4 (S901). In step S901, for example, the control unit 81 checks the brightness, placement of the display devices, and usage time of the display devices for multiple display devices (1A, 1B, 1C). It also checks external information such as the placement of passengers and whether it is daytime or nighttime. For example, the control unit 81 confirms the placement of passengers and whether it is daytime or nighttime by checking information acquired from sensors mounted on the vehicle (for example, illuminance sensor 905, in-vehicle camera 919). In step S901, the control unit 81 performs CAN communication as an example.

[0066] Then, the control unit 81 adjusts the brightness of the display devices (1A, 1B, 1C) according to the situation (S902). That is, the control unit 81 adjusts the brightness of the display devices (1A, 1B, 1C) based on the information confirmed in step S901. Then, the control unit 81 displays the image (S903). If the brightness of the display devices was adjusted in step S902, the image is displayed at the adjusted brightness.

[0067] Referring to Figures 10-15, a specific example will be explained. In step S901, if it is confirmed that only the driver 71 is in the vehicle, then in step S902, control may be performed to equalize the brightness of the images on each display device (1A, 1B, 1C) (Determination Example 1). That is, the control unit 81 may adjust the brightness of each display device (1A, 1B, 1C) so that the brightness of the images as seen from the driver 71 is the same for each display device (1A, 1B, 1C).

[0068] Here, as an example, as shown in Figure 7B, the control unit 81 may adjust the brightness of each display device (1A, 1B, 1C) other than the display device furthest from the driver 71 so that the brightness of the image as seen from the driver 71 matches the brightness of the image of the display device furthest from the driver 71. That is, as shown in Figure 11A, the control unit 81 may adjust the brightness of the display devices so that the brightness of the image from the display device closer to the driver 71 (in this example, display device C (1C)) and the brightness of the image from the display device in the center of the vehicle width direction (X direction) as seen from the driver 71 (in this example, display device B (1B)) match the brightness of the image from the display device furthest from the driver 71 (in this example, display device A (1A)).

[0069] The control unit 81 can adjust the brightness of the display device, for example, by dimming the backlight or video signal of the display device. Here, adjusting the brightness of the backlight is preferable because it consumes less power. In the case of LEDs, brightness can be adjusted by adjusting the number of LEDs lit or by adjusting the current. When adjusting the brightness of the backlight, as shown in Figure 11B, for example, in order to ensure that the brightness of the image as seen from the driver 71 is uniform for each display device (1A, 1B, 1C), the brightness of the backlight of the display device furthest from the driver 71 (here, display device A (1A)) is maintained at 100% [%], the brightness of the backlight of the display device in the center in the vehicle width direction (X direction) (here, display device B (1B)) is set to 100 × a / b [%], and the brightness of the backlight of the display device closer to the driver (here, display device C (1C)) is set to 100 × a / c [%]. In other words, when using the brightness of the backlight of display device A (1A) as a basis, the brightness of the backlight of display device B (1B) in the central part in the vehicle width direction (X direction) is adjusted to dim from 100 [%] to 100 × a / b [%], and the brightness of the backlight of display device C (1C) closer to the driver is adjusted to dim from 100 [%] to 100 × a / c [%]. Here, a, b, and c are values, and in this case, the relationship a < b < c holds. The values ​​a, b, and c may be set in advance based on the position of the driver's seat, the arrangement of the display devices (1A, 1B, 1C), etc., and stored in an appropriate storage device. The values ​​a, b, and c represent the luminance of the display devices. As an example, a = 5,000 cd / m ２ ,b=6,000cd / m ２ , c=8,000cd / m ２ The values ​​will be such as these. The control unit 81 may then read the values ​​from the storage device and perform control.

[0070] In this example, the case where the driver 71 is located on the right side in the vehicle width direction (X direction) has been described. In contrast, when the driver 71 is located on the left side in the vehicle width direction (X direction) (i.e., when the driver's seat is located on the left side in the vehicle width direction (X direction)), the brightness of the display device may be adjusted in the same manner as described above. However, in this case, the control unit 81 adjusts the brightness of the display device so that the brightness of the image from display device A (1A) and the brightness of the image from display device B (1B) as viewed from the driver 71 match the brightness of the image from display device C (1C) as viewed from the driver 71.

[0071] Next, let's explain another specific example. If it is confirmed in step S901 that only the driver 71 is in the vehicle, then in step SS902, the brightness of the display devices (1A, 1B, 1C) may be adjusted to gradually increase (or decrease) their brightness (Determination Example 2). That is, the control unit 81 may adjust the brightness of each display device (1A, 1B, 1C) in steps so that the brightness of the image as seen from the driver 71 is gradually increased (or decreased) for each display device (1A, 1B, 1C).

[0072] In this example, the brightness of each display device (1A, 1B, 1C) is gradually changed by adjusting both the backlight and the video signal, eliminating any discomfort caused by differences in brightness. First, the control unit 81 adjusts the brightness by adjusting the backlight output. Then, the brightness is adjusted using the video signal. Through this control, the brightness of each display device (1A, 1B, 1C) can be adjusted to any desired level.

[0073] As shown in Figure 12A, first, the control unit 81 adjusts the backlight output to change the brightness by more than one step, to a degree that does not cause discomfort to the user. Then, based on image correction using the video signal, brightness adjustment is performed to achieve a one-step change in brightness for each display device. In Figure 12A, the backlight output adjustment is shown by a curve, and the shaded area represents the part where brightness adjustment is performed by image correction.

[0074] As shown in Figure 12B, the control unit 81 adjusts the backlight output based on the video signal, for example, by setting the brightness of the backlight of the display device furthest from the driver 71 (here, display device A (1A)) to 100 × d / a [%], the brightness of the backlight of the display device in the center in the vehicle width direction (X direction) (here, display device B (1B)) to 100 × a / b [%], and the brightness of the backlight of the display device closer to the driver (here, display device C (1C)) to 100 × b / c [%]. In other words, the brightness of the backlight of display device A (1A) is adjusted from 100% to 100 × d / a [%], the brightness of the backlight of display device B (1B) in the center in the vehicle width direction (X direction) is adjusted from 100% to 100 × a / b [%], and the brightness of the backlight of display device C (1C) on the side closer to the driver is adjusted from 100% to 100 × b / c [%]. Here, a, b, c, and d are values, and in this case, the relationship is d < a < b < c. The values ​​a, b, c, and d may be set in advance based on the position of the driver's seat, the arrangement of the display devices, the magnitude of one adjustment step, etc., and may be stored in an appropriate memory device. The values ​​a, b, and c indicate the luminance of the display device, and d depends on how dimmed the display device is, but as an example, a = 5,000 cd / m ２ ,b=6,000cd / m ２ , c=8,000cd / m ２ The values ​​are as follows: d = 4,000 cd / m ２ This becomes the value. The control unit 81 may then read the value from the storage device and perform control.

[0075] In this example, the case where the driver 71 is located on the right side in the vehicle width direction (X direction) was described. In contrast, when the driver 71 is located on the left side in the vehicle width direction (X direction) (i.e., when the driver's seat is located on the left side in the vehicle width direction (X direction)), the control unit 81 may adjust the brightness of the display devices (1A, 1B, 1C) in the same manner as described above. That is, the control unit 81 may adjust the brightness by adjusting the backlight output, and then adjust the brightness using the video signal.

[0076] Next, another specific example will be described. In step S901, if the control unit 81 confirms the presence of the driver 71 and the passenger 72 sitting next to the driver 71 (i.e., the passenger 72 sitting in the passenger seat next to the driver's seat), it may adjust the brightness of the two display devices to match in step S902 (Determination Example 3).

[0077] Here, as shown in Figure 13A, the control unit 81 may adjust the brightness of the display device closer to the driver 71 (in this example, display device C (1C)) so that the brightness of the image as seen from the driver 71 on the display device closer to the driver 71 (in this example, display device C (1C)) matches the brightness of the image as seen from the driver 71 on the central display device in the vehicle width direction (X direction) (in this example, display device B (1B)). In conjunction with this, the control unit 81 may also adjust the brightness of the display device closer to the passenger 72 (in this example, display device A (1A)) so that the brightness of the image as seen from the passenger 72 on the display device closer to the passenger 72 (in this example, display device A (1A)) matches the brightness of the image as seen from the passenger 72 on the central display device in the vehicle width direction (X direction) (in this example, display device B (1B)).

[0078] In Figure 13A, the white graph shows the brightness as seen from the driver's perspective 71, and the gray graph shows the brightness as seen from the passenger's perspective 72. This control ensures that the brightness of two of the three screens seen by the driver 71 and passenger 72 is equal, thereby reducing the discomfort caused by the difference in brightness between the images seen by the driver 71 and passenger 72 in the front seat.

[0079] The control unit 81 can adjust the brightness by adjusting the backlight or video signal of the display device. Here, adjusting the brightness of the backlight is preferable because it consumes less power. When adjusting the brightness of the backlight, as shown in Figure 13B, the control unit 81 maintains the brightness of the backlight of the central display device (display device B (1B)) in the vehicle width direction (X direction) at 100% [%], sets the brightness of the backlight of the display device closer to the driver 71 (display device C (1C)) to 100 × b / c [%], and adjusts the brightness of the backlight of the display device closer to the passenger 72 (display device A (1A)) to 100 × b / c [%]. Here, b and c are values, and in this case, the relationship b < c holds. The values ​​b and c may be predetermined (set) based on the position of the driver's seat, the position of the passenger seat, the arrangement of the display devices, etc., and stored in an appropriate storage device. The control unit 81 may then read the values ​​from the storage device and perform the adjustment.

[0080] Here, the case was described in which, before brightness adjustment, the brightness of the image as seen by the driver 71 on the display device closer to the driver 71 (here, display device C (1C)) is approximately equal to or equal to the brightness of the image as seen by the passenger 72 on the display device closer to the passenger 72 (here, display device A (1A)). Before brightness adjustment, if the brightness of the image as seen by the driver 71 on the display device closer to the driver 71 is different from the brightness of the image as seen by the passenger 72 on the display device closer to the passenger 72, the brightness adjustment of display devices A (1A) and C (1C) may be performed using different values. Here, these values ​​may be predetermined (set) based on the position of the driver's seat, the position of the passenger seat, the arrangement of the display devices, etc., and stored in an appropriate storage device. The control unit 81 may then read the values ​​from the storage device and perform the adjustment.

[0081] In this example, the case where the driver 71 is located on the right side in the vehicle width direction (X direction) has been described. In contrast, if the driver 71 is located on the left side in the vehicle width direction (X direction) (i.e., if the driver's seat is located on the left side in the vehicle width direction (X direction)), the control unit 81 may adjust the brightness of the display device in the same manner as described above. In other words, the control unit 81 may adjust the brightness of the display device on the side closer to the driver 71 (display device A (1A) in this description) so that the brightness of the image as seen by the driver 71 matches the brightness of the image as seen by the driver 71 for the display device in the center in the width direction of the vehicle, and may also adjust the brightness of the display device on the side closer to the passenger 72 (display device C (1C) in this description) so that the brightness of the image as seen by the passenger 72 matches the brightness of the image as seen by the passenger 72 for the display device in the center in the width direction of the vehicle.

[0082] Next, another specific example will be described. If the control unit 81 confirms in step S901 that only the driver 71 is in the vehicle and that the predetermined usage time for the display devices (1A, 1B, 1C) has been exceeded, it may perform control in step S902 to adjust the backlight output after the predetermined time has elapsed to adjust the brightness of the display devices (Determination Example 4). Next, this example will be specifically explained with reference to Figures 14A and 14B.

[0083] The change in brightness over time differs for each display device (1A, 1B, 1C). Due to the decrease in the transmittance of the optical components, the display device with the highest backlight output dims the fastest. Therefore, as shown in the upper part of Figure 14A, even if the brightness of the display devices is adjusted initially to match the apparent brightness, differences in brightness gradually occur over time.

[0084] Therefore, as shown in the lower diagram of FIG. 14A, after a predetermined time has elapsed (after T1), the control unit 81 adjusts the output of the backlight to match the characteristics of the display device with the fastest luminance decrease (here, display device A (1A)). That is, after a predetermined time has elapsed, the control unit 81 adjusts the luminance of the other display devices so that the luminance of the video viewed by the driver 71 for each display device (1A, 1B, 1C) matches the luminance of the video of the display device (here, display device A (1A)) that displays the video with the lowest luminance among the respective display devices (1A, 1B, 1C) when viewed by the driver 71.

[0085] Further, the control unit 81 performs control to match the characteristics of the display device with the fastest luminance decrease (here, display device A (1A)) by decreasing the output of the backlight in accordance with a cycle of a predetermined time, for example, T1 to T4, that is, every 100 hr (100 hours) elapsed. By this control, the luminance difference between the respective display devices (1A, 1B, 1C) due to changes over time can be suppressed.

[0086] As shown in FIG. 14B, initially (that is, at T0), the control unit 81 controls to maintain the luminance of the backlight of the display device (here, display device A (1A)) at 100 [%] and adjust the luminance of the backlights of the other display devices (1B, 1C) in order to match the apparent brightness. Here, control is performed such that the luminance of the backlight of display device B (1B) is 100 × a / b [%] and the luminance of the backlight of display device C (1C) is 100 × a / c [%]. Here, a, b, and c are values, and in this case, there is a relationship of a < b < c. The values a, b, and c are determined (set) in advance based on the position of the driver's seat, the arrangement of the display devices, etc., and may be stored in an appropriate storage device. The values a, b, and c indicate the luminance of the display devices. As an example, a = 5,000 cd / m ２ , b = 6,000 cd / m ２ , c = 8,000 cd / m ２ and so on. Then, the control unit 81 may read the values from the storage device and perform control.

[0087] Subsequently, after a predetermined time has elapsed, the control unit 81 adjusts the backlight brightness of display device A (1A) to 100% and the backlight brightness of display device B (1B) to 100 × (a / b) × α% and the backlight brightness of display device C (1C) to 100 × (a / c) × β%. The control unit also repeats this adjustment according to a predetermined time cycle (T1 to T4).

[0088] Here, α and β are attenuation coefficients, and the values ​​of the attenuation coefficients at predetermined times (here, T1, T2, T3, T4) can be calculated from the results of reliability tests. The attenuation coefficients are stored in advance in a suitable memory device; for example, α = 0.9 and β = 0.8, and the control unit 81 may retrieve the attenuation coefficients from the memory device and make adjustments.

[0089] Thus, the display device that initially maintains its backlight brightness at 100% dims the fastest. After a predetermined time has elapsed, the brightness of the other display devices is adjusted to match that display device. In this example, the backlight brightness of display device A (1A) is initially maintained at 100%, and after a predetermined time has elapsed, the brightness of display devices B and C is adjusted using an attenuation coefficient. However, the backlight brightness of a display device different from display device A may be initially maintained at 100%, and after a predetermined time has elapsed, the brightness of a display device different from that display device may be adjusted based on a similar method (a method using an attenuation coefficient).

[0090] Next, another specific example will be described. In step S901, the control unit 81 confirms that it is nighttime and, when displaying an alert, may in step S902 temporarily brighten the display device that displays the alert to prompt the driver to pay attention (Decision Example 5).

[0091] At night, if the display devices (1A, 1B, 1C) are too bright, it will interfere with driving, so the control unit 81 controls each of the display devices (1A, 1B, 1C) to dim. As shown in the upper diagram of Figure 15A, the control unit 81 controls each of the display devices (1A, 1B, 1C) as an example so that the apparent brightness (the brightness of the image as seen by the driver) is d.

[0092] When an alert is displayed, such as when a person is near vehicle 2, the control unit 81 adjusts / controls the brightness of the display device that displays the alert, as shown in the lower diagram of Figure 15A. Here, the control unit 81 adjusts / controls the apparent brightness of the display device A (1A) that displays the alert from d to a. This adjustment / control can improve the display effect of the alert. However, if it becomes too bright, the driver may feel dazzled, so it is necessary to set the brightness appropriately.

[0093] The control unit 81 may perform control to reduce the brightness of the backlights of each display device (1A, 1B, 1C) at night. As shown in Figure 15B, for example, assuming the backlight output during the day is 100 [%], the control unit 81 may perform control at night to set the brightness of the backlight of display device A (1A) to 100 × d / a [%], the brightness of the backlight of display device B (1B) to 100 × d / b [%], and the brightness of the backlight of display device C (1C) to 100 × d / c [%]. Here, a, b, c, and d are values, and in this case, the relationship is d < a < b < c. The values ​​a, b, c, and d may be set in advance based on the position of the driver's seat, the arrangement of the display devices, etc., and stored in an appropriate storage device. The control unit 81 may then read the values ​​from the storage device and perform the control.

[0094] Furthermore, when displaying an alert, the control unit 81 may control the backlight output of the display device that displays the alert (in this case, display device A (1A)) to the same output as during the daytime (in this case, 100%). Note that the alert may be displayed on a display device other than display device A (1A), in which case the control unit 81 increases the backlight output of the display device that displays the alert.

[0095] The control unit 81 may determine whether it is nighttime or daytime by an appropriate method. The control unit 81 may make this determination by acquiring information from appropriate sensors, such as an illuminance sensor 905 or an external camera 920. Alternatively, the control unit 81 may make this determination by acquiring information regarding whether it is nighttime or daytime from external devices 400, terminal devices 410, external servers 700, etc., via communication.

[0096] In this example, the case where the driver is positioned on the right side in the vehicle width direction (X direction) was described. In contrast, when the driver is positioned on the left side in the vehicle width direction (X direction) (i.e., when the driver's seat is located on the left side in the vehicle width direction (X direction)), the control unit 81 may adjust the brightness of the display device in the same manner as described above. Specifically, the control unit 81 may control the brightness of the backlight to be reduced at night, and when displaying an alert, it may control the output of the backlight of the display device that displays the alert to be increased.

[0097] In the above description, display devices A (1A), B (1B), and C (1C) can, for example, have basically the same configuration as display device 1. However, for example, each display device (1A, 1B, 1C) may be controlled by a common processor, or other modifications may be made as appropriate.

[0098] Furthermore, as shown in Figure 7A, the display device A (1A) may be rotatably mounted around a rotation axis A1 in the vertical direction (Z direction) of the vehicle 2. The display device A (1A) may be configured to rotate the displayed image around a rotation axis A2 in the longitudinal direction (Y direction) of the vehicle 2 in accordance with the rotation of the display device A (1A). Similarly, the display device C (1C) may be rotatably mounted around a rotation axis A3 in the vertical direction (Z direction) of the vehicle 2. The display device C (1C) may be configured to rotate the displayed image around a rotation axis A4 in the longitudinal direction (Y direction) of the vehicle 2 in accordance with the rotation of the display device C (1C). In addition, the display device B may be configured to allow adjustment of the displayed image in the vertical direction.

[0099] Although embodiments have been described above, the present invention is not limited to the embodiments described above, and includes various modifications and equivalent configurations within the spirit of the attached claims. For example, the embodiments described above are described in detail for the purpose of explaining the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to having all the configurations described. Also, for example, some of the configurations of the embodiments may be added, deleted, or replaced with other configurations.

[0100] The technology described in this embodiment makes it possible to prevent traffic accidents by providing a display device that can display a good virtual image, reduces the driver's eye movement, and contributes to supporting safe driving. This contributes to the United Nations' Sustainable Development Goal (SDG), specifically "Goal 3: Ensure good health and well-being for all."

[0101] 1A Display device (virtual image display device) 1B Display device (virtual image display device) 1C Display device (virtual image display device) 11 Display panel 20 Light source 81 Control unit

Claims

1. A display system comprising: a plurality of display devices mounted on a vehicle that project image light; and a control unit that controls each of the display devices, wherein the control unit adjusts the brightness of the display devices according to the situation.

2. A display system according to claim 1, characterized in that the plurality of display devices are positioned in front of the driver's seat and arranged in a line in the vehicle width direction.

3. A display system according to claim 1, wherein the control unit adjusts the brightness of other display devices so that the brightness of the image on each of the display devices as viewed by the driver matches the brightness of the image on the display device furthest from the driver as viewed by the driver.

4. A display system according to claim 1, wherein the control unit adjusts the brightness of each of the display devices in steps.

5. A display system according to claim 4, characterized in that the control unit adjusts the brightness of each of the display devices in steps by adjusting the video signal after adjusting the backlight output.

6. A display system according to claim 2, characterized in that, when the control unit confirms that the driver is in the vehicle and that a passenger next to the driver is in the vehicle, it adjusts the brightness of the display device closest to the driver so that the brightness of the image as seen by the driver on the display device closest to the driver matches the brightness of the image as seen by the driver on the display device in the center in the width direction of the vehicle, and adjusts the brightness of the display device closest to the passenger so that the brightness of the image as seen by the passenger on the display device closest to the passenger matches the brightness of the image as seen by the passenger on the display device in the center in the width direction of the vehicle.

7. A display system according to claim 1, wherein the control unit, upon confirming that the usage time of a plurality of the display devices exceeds a predetermined time, adjusts the brightness of the other display devices so that the brightness of the image on each of the display devices as viewed by the driver matches the brightness of the image on the display device that displays the image with the lowest brightness among the display devices as viewed by the driver.

8. A display system according to claim 7, wherein the control unit periodically repeats a control to adjust the brightness of the display device.

9. A display system according to claim 1, wherein the control unit reduces the brightness of each of the display devices when it is nighttime.

10. A display system according to claim 9, wherein the control unit increases the brightness of the display device that displays the alert when an alert is displayed.

Images