Display system

Abstract

To provide a technology that can improve the visibility of content projected in front of the driver. According to this invention, it contributes to Sustainable Development Goal 3, "Good Health and Well-being." [Solution] A display system mounted on a vehicle comprises a light source, a display panel into which light from the light source enters, and a light-transmitting / light-blocking switching unit into which image light projected by the display panel enters. The light-transmitting / light-blocking switching unit switches between a light-blocking state and a semi-transparent state in part or all of the area into which the image light enters, depending on the projected image.

Description

Technical Field

[0001] The present invention relates to a display device, a vehicle, and a display system.

Background Art

[0002] There is known a virtual image display device or a head-up display (HUD) device that projects image light onto the windshield of an automobile or the like to form a virtual image and displays traffic information such as route information and traffic jam information, and automobile information such as remaining fuel amount and coolant temperature.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a problem of providing a technology capable of improving the visibility of content projected in front of a driver.

Means for Solving the Problems

[0005] According to the present invention, as an example, the following display device is provided. A display system mounted on a vehicle, comprising a light source, a display panel onto which light from the light source is incident, and a transmission / light-shielding switching unit onto which image light projected by the display panel is incident, wherein the transmission / light-shielding switching unit switches between a light-shielding state and a semi-transmissive state in part or all of the region where the image light is incident, depending on the projected image.

Effects of the Invention

[0006] According to the present invention, the visibility of content can be improved, and a more suitable display system can be realized. Other problems, configurations, and effects not mentioned above will be clarified by the following description of embodiments for carrying out the invention. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows an example of a vehicle equipped with a display device. [Figure 2] This is a diagram illustrating an example of an image display configuration. [Figure 3A] This figure shows an example of a display when the light-transmitting / light-blocking switching section blocks light. [Figure 3B] This figure shows a magnified view of the area where the video is displayed in Figure 3A. [Figure 4A] This figure shows an example of a display when the light transmission / blocking switching section partially transmits light. [Figure 4B] This figure shows a magnified view of the area where the video is displayed in Figure 4A. [Figure 5A] This figure shows an example of a display when the light-transmitting / light-blocking switching section blocks only the light related to the display area. [Figure 5B] This figure shows a magnified view of the area where the video is displayed in Figure 5A. [Figure 6A] This figure shows an example of the structure of a light-transmitting / light-blocking switching section. [Figure 6B] This figure shows a magnified view of the area where the video is displayed in Figure 6A. [Figure 7A] This diagram illustrates an example of the light-blocking state of the light-transmitting / light-blocking switching section. [Figure 7B] This diagram illustrates an example of the light-blocking state of the light-transmitting / light-blocking switching section. [Figure 8A] This diagram illustrates an example of the semi-transparent state of the light-transmitting / light-blocking switching section. [Figure 8B] This diagram illustrates an example of the semi-transparent state of the light-transmitting / light-blocking switching section. [Figure 9A] This diagram illustrates an example of the semi-transparent state of the light-transmitting / light-blocking switching section. [Figure 9B] This is a diagram for explaining an example of the semi-transmissive state of the light-shielding switching section. [Figure 10A] This is a diagram for explaining an example of the semi-transmissive state of the light-shielding switching section. [Figure 10B] This is a diagram for explaining an example of the semi-transmissive state of the light-shielding switching section. [Figure 11] This is a diagram showing an example of the configuration of a vehicle. [Figure 12] This is a diagram showing an example of the configuration of a display device. [Figure 13] This is a diagram showing an example of the configuration of a display device. [Figure 14] This is a flowchart showing an example of the control of the light-shielding switching section. [Figure 15] This is a diagram for explaining an example of determination item A in FIG. 14. [Figure 16A] This is a diagram showing a configuration example of an image forming unit. [Figure 16B] This is a diagram showing an example of the light reflection section of a reflection optical element. [Figure 17] This is a diagram showing a configuration example of an image forming unit. [Figure 18] This is a diagram showing a structural example of an image forming unit. [Figure 19] This is a diagram showing a structural example of an image forming unit. [Figure 20] This is a diagram showing a structural example of an image forming unit. [Figure 21] This is a flowchart showing an example of the control of the light-shielding switching section.

Embodiments for Carrying Out the Invention

[0008] 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.

[0009] In explanations, when describing program-based processing, the focus may sometimes be on the program, functions, or processing units. However, the core 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 CPUs / MPUs and GPUs. Processing is not limited to software program processing; it can also be implemented using dedicated circuits. FPGAs, ASICs, CPLDs, etc., can be used as dedicated circuits.

[0010] First, an example of a vehicle equipped with a display device will be described with reference to Figure 1. Figure 1 is a schematic diagram showing an example configuration of a vehicle equipped with a display device or virtual image display device. With respect to the vehicle and driver, the horizontal direction x is the left-right direction, the lateral direction of the vehicle, or the width direction of the vehicle; the vertical direction y is the up-down direction of the vehicle, or the longitudinal direction; and the horizontal direction z, perpendicular to the lateral direction of the vehicle, is the front-rear direction of the vehicle or the direction of travel of the vehicle. The display device may also be called a virtual image display device. The following explanation will use the term "display device".

[0011] 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 occurring in the vehicle 2, periodically detect values ​​of various parameters related to driving conditions, and acquire road information from the navigation system. Vehicle information 4 includes, for example, vehicle 2 speed information, gear information, steering angle information, lamp illumination information, ambient light information, distance information, infrared information, engine ON / OFF information, camera image information, acceleration 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 current time information in addition to latitude and longitude. Vehicle information 4 also includes input information from the driver.

[0012] Based on the vehicle information 4, the display device 1 projects / emits image light onto the display area 5 of the windshield 3. This allows the display device 1 to display the image to the driver of the vehicle 2. 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 such as a combiner.

[0013] 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, for example, using a CAN (Controller Area Network). 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.

[0014] Furthermore, other connection configurations may be employed. 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.

[0015] 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 is a system in which the controller 100 can control the vehicle 2 using vehicle information 4.

[0016] Next, an example of the configuration for image display will be described with reference to Figure 2. The display device 1 is installed, for example, on or inside the dashboard 70. The display device 1 projects image light toward the display area 5 of the windshield 3 described above. The display area 5 of the windshield 3 is provided with a light-transmitting / light-blocking switching unit. This light-transmitting / light-blocking switching unit is used to control the transmission and blocking of light, and is shown by hatching in the figure. A specific example of the configuration of the light-transmitting / light-blocking switching unit will be described in detail later. When the light-transmitting / light-blocking switching unit blocks the light, the driver 9 of the vehicle can see the display image that is not superimposed on the scenery. When the light-transmitting / light-blocking switching unit partially transmits the light, the driver 9 of the vehicle 2 can see a virtual image 8 corresponding to the display image superimposed on the scenery. The light-transmitting / light-blocking switching unit may be provided in the display device 1 or in the vehicle 2.

[0017] Next, with reference to Figures 3A and 3B, an example of display when the light-transmitting / light-blocking switching section blocks light will be described. In this example, the entire surface of the light-transmitting / light-blocking switching section 924a is in a light-blocking state, which reduces the background brightness of the image, and visibility can be obtained even with low image brightness. Therefore, for example, when the background of the image is black, navy blue, or indigo, the low image brightness enables power saving during image display. Alternatively, because the image brightness is low, the energy generated during image display (thermal energy and light energy in this example) is reduced. This suppresses product degradation and extends the product life. In addition, because ambient light (sunlight) is blocked by the light-transmitting / light-blocking switching section 924a, ambient light does not enter the display panel of the display device. As a result, the temperature rise of the display panel is suppressed, and the degradation of the display panel is suppressed.

[0018] As shown in Figures 3A and 3B, the light-transmitting switching section 924a is provided, for example, across the entire lower part of the windshield 3 so as not to obstruct the driver's view. That is, the light-transmitting switching section 924a is provided on the lower part of the windshield 3, extending from left to right. However, it is sufficient to provide the light-transmitting switching section in the area used for displaying images. In other words, the light-transmitting switching section may be provided in the display area 5 or according to customer needs.

[0019] Next, with reference to Figures 4A and 4B, an example of a display when the light-transmitting switching section partially transmits light will be described. In this example, since the entire surface of the light-transmitting switching section 924a becomes semi-transparent, the driver of the vehicle can see ahead through the light-transmitting switching section 924a, thereby increasing driving safety. The light-transmitting switching section 924a can be provided in the same manner as described in Figures 3A and 3B above.

[0020] Next, with reference to Figures 5A and 5B, an example of a display where the light-transmitting / light-blocking switching section blocks only the light related to the display area will be described. In this example, only the entire area of ​​the light-transmitting / light-blocking switching section 924a related to the display area 5 is in a light-blocking state, while the remaining area is semi-transparent. Therefore, the incidence of external light (sunlight) on the display panel can be suppressed, thereby suppressing the temperature rise and light degradation of the display panel. In addition, forward visibility is obtained due to the semi-transparent portion, improving driving safety.

[0021] The light-shielding switching unit 924a can adjust the area within the display area 5 that is shaded according to the content of the video being displayed. For example, by shading not only the displayed content but also the background portion of the video (for example, the outline of the content) in the light-shielding switching unit 924a, good visibility can be obtained even at low video brightness. On the other hand, the light-shielding switching unit 924a may also shade only the portion that overlaps with the content displayed in the display area 5, leaving the rest semi-transparent.

[0022] Next, an example of the shape of the light-transmitting switching section will be described with reference to Figures 6A and 6B. For example, the light-transmitting switching section 924b can be provided at the bottom of the windshield 3 such that its length in the left-right direction decreases as it moves from the bottom to the top of the windshield 3. As shown in the figures, the light-transmitting switching section 924b blocks light from the portion that overlaps the content and the surrounding portion which is roughly trapezoidal or trapezoidal in shape (in this example, the entire display area 5) as it moves from the bottom to the top. In addition, the display device 1 projects video light that displays content with a sense of depth, thereby realizing a display that makes it easy for the vehicle driver to perceive depth.

[0023] More specifically, if the light-transmitting / light-blocking switching section 924b has a shape that is longer than the area into which the image light is incident in the left-right or width direction of the vehicle, and becomes a roughly trapezoidal or trapezoidal shape in which the length in the left-right direction decreases as it moves from the bottom to the top of the vehicle, then by making the size of the content displayed by the display panel, the font size, or the left-right dimensions of the vehicle within the same content smaller as it moves from the bottom to the top of the vehicle, the driver will be able to perceive a sense of depth in the displayed image more easily. It should be noted that this type of display that makes it easier to perceive depth is not limited to cases where the light-transmitting / light-blocking switching section 924b is provided in the display area 5, but may also be provided in cases where, for example, black ceramic printing is provided as a light-blocking section in the display area 5. If the light-shielding portion provided in the display area 5 has a shape that is longer than the area into which the image light is incident in the left-right direction of the vehicle, and has a roughly trapezoidal or trapezoidal shape in which the length in the left-right direction decreases as it moves from the bottom to the top of the vehicle, then by reducing the size of the content drawn by the display panel, the font size, or the left-right dimensions of the vehicle within the same content as it moves from the bottom to the top of the vehicle, the driver will be able to perceive a sense of depth in the displayed image more easily.

[0024] In the figure, the light-transmitting / light-blocking switching section 924b is roughly trapezoidal or trapezoidal in shape, with its length decreasing from left to right as it moves from the bottom to the top of the vehicle. However, the same effect can be obtained by having only the roughly trapezoidal portion (i.e., the entire display area 5) be in a light-blocking state, while the other portion is semi-transparent, and projecting video light to display content with a sense of perspective. Therefore, the shape of the light-transmitting / light-blocking switching section may be changed as appropriate. The light-transmitting / light-blocking switching section may, for example, be located at the bottom of the windshield 3 and be longer than the display area 5 on which the display panel 11 projects the video light in the left-right direction of the vehicle. Furthermore, this light-transmitting / light-blocking switching section may be in a light-blocking state throughout the entire display area 5, and semi-transparent in the other portion.

[0025] Next, an example of the configuration of the light-transmitting / light-shielding switching section will be explained in more detail using Figures 7-10. The light-transmitting / light-shielding switching section (924a, 924b) contains liquid crystal and dye or pigment, and is configured to orient the dye or pigment in a predetermined direction using the liquid crystal.

[0026] Here, it is desirable that the light-transmitting / light-blocking switching section (924a, 924b) be normally black. Normally black is in a light-blocking state when no voltage is applied. In this case, when the vehicle is not in use, the incidence of ambient light SL, such as sunlight, on the display panel can be suppressed, and product deterioration can be reduced. Specifically, it is possible to suppress the incidence of ambient light SL when the vehicle engine is OFF (when the ignition switch is OFF), or when the electrically driven vehicle is not in use (when the power switch for enabling the electric vehicle to run is OFF), etc.

[0027] The light-transmitting and light-blocking switching section (924a, 924b) is in the form of a sheet and, for example, may be provided on the driver's side surface (inside of the windshield 3) of the windshield 3. The light-transmitting and light-blocking switching section (924a, 924b) may also be included in the interlayer of the windshield 3. Furthermore, a half-mirror, reflective polarizing film, etc., may be provided on the incident surface (the surface to which light is incident) of the light-transmitting and light-blocking switching section (924a, 924b). The half-mirror, reflective polarizing film, etc., may be provided on the incident surface to which image light IL is incident, or on the incident surface to which ambient light SL is incident. Since the image light IL incident on the light-transmitting and light-blocking switching section (924a, 924b) including the half-mirror, reflective film, etc., is reflected with high efficiency by the half-mirror, reflective film, etc., power saving during image display is achieved. This suppresses product degradation due to energy generated during image display (in this example, thermal energy and light energy), and extends the product life. On the other hand, ambient light SL incident on the light-transmitting / light-blocking switching section (924a, 924b) is blocked by a half-mirror, reflective polarizing film, etc., so that ambient light does not enter the display panel of the display device. As a result, the temperature rise of the display panel is suppressed, and the deterioration of the display panel is inhibited.

[0028] An example of the light-shielding state of the light-transmitting light-shielding switching section will be explained with reference to Figures 7A and 7B. In this example, the display device projects image light IL toward the light-transmitting light-shielding switching section (924a, 924b), and the image light IL is reflected by the light-transmitting light-shielding switching section (924a, 924b) and directed toward the driver. The driver can see a virtual image corresponding to the displayed image (i.e., an image display without superimposed scenery) on the light-shielding light-shielding switching section (924a, 924b). In addition, ambient light SL incident on the light-transmitting light-shielding switching section (924a, 924b) is absorbed (or reflected) by at least the light-shielding light-shielding switching section (924a, 924b) and does not penetrate into the interior of the vehicle beyond the light-transmitting light-shielding switching section (924a, 924b). Here, as shown in Figure 7B, in the light-shielding areas of the light-shielding switching sections (924a, 924b), the dyes or pigments contained within these sections are randomly oriented in the xy-plane or xyz space. In other words, in the light-shielding areas, the dyes or pigments do not align in a specific direction. In the same figure, the dyes or pigments are indicated by the symbol D.

[0029] Referring to Figures 8A and 8B, an example of the semi-transparent state of the light-transmitting switching section will be explained. As shown in the figures, in this example, in the semi-transparent area of ​​the light-transmitting switching section (924a, 924b), the dye or pigment within the light-transmitting switching section (924a, 924b) is oriented in the x-axis direction corresponding to the vehicle width direction. In the figures, the dye or pigment is indicated by the symbol D. The polarization component of the video light IL (in this example, the P-polarized component) is incident on the light-transmitting switching section (924a, 924b), and a portion of the video light IL is Fresnel reflected at the incident surface and directed towards the driver. In addition, the polarization component of the ambient light SL (in this example, the P-polarized component) is transmitted through the light-transmitting switching section (924a, 924b). As a result, the display device projects P-polarized video light IL, allowing the driver to see a virtual image corresponding to the displayed image superimposed on the scenery.

[0030] Furthermore, since the light-transmitting and light-blocking switching sections (924a, 924b) are provided in a part of the windshield 3, it is conceivable that ambient light SL may enter the vehicle from the windshield 3 without passing through the light-transmitting and light-blocking switching sections (924a, 924b). In this case, even if the driver wears polarized sunglasses (in this example, sunglasses that block S-polarization) as a countermeasure against ambient light SL that directly enters the vehicle, the polarization component of the image light IL (in this example, the P-polarization component) and the polarization component of the ambient light SL (in this example, the P-polarization component) will pass through the polarized sunglasses, so the driver will be able to see the virtual image corresponding to the displayed image superimposed on the scenery.

[0031] Furthermore, as shown in the figure, even when the display device projects S-polarized image light IL onto the light-transmitting switching section (924a, 924b) where the dye or pigment is oriented in the x-axis direction, the image light IL is Fresnel-reflected at the incident surface of the light-transmitting switching section (924a, 924b), and the driver can see a virtual image corresponding to the displayed image.

[0032] Furthermore, when the image light IL is S-polarized, the component of the image light IL that is not reflected by Fresnel at the incident surface of the transmission-shielding switching section (924a, 924b), i.e., the image light IL that enters the interior of the transmission-shielding switching section (924a, 924b), is absorbed by the dye or pigment oriented in the x-axis direction. This suppresses the double image caused by Fresnel reflection of the image light IL on the back surface (outside the vehicle) of the windshield 3.

[0033] The same figure was used to illustrate the light-transmitting and light-shielding switching sections (924a, 924b) in which the dye or pigment D is oriented in the x-axis direction. However, in the light-transmitting and light-shielding switching sections (924a, 924b), the dye or pigment D may also be oriented in the y-axis direction. In this case as well, the image light IL is Fresnel-reflected at the incident surface of the light-transmitting and light-shielding switching sections (924a, 924b) regardless of the polarization direction of the image light, and the driver can see a virtual image corresponding to the displayed image.

[0034] Furthermore, when the image light IL is P-polarized, as described above, the image light IL that enters the transmission / shielding switching section (924a, 924b) is absorbed by the dye or pigment D, thereby suppressing the generation of double images.

[0035] Referring to Figures 9A and 9B, an example of the semi-transparent state of the light-transmitting switching section will be explained. In this example, the orientation direction of the light-transmitting switching section (924a, 924b) is different from that described above. That is, in the semi-transparent area of ​​the light-transmitting switching section (924a, 924b), the dye or pigment within the light-transmitting switching section (924a, 924b) is oriented to form an angle of approximately 45° along the xy plane with respect to the x-axis direction (corresponding to the vehicle width direction) and the y-axis direction (corresponding to the vehicle's vertical direction). In the same figure, the dye or pigment is indicated by the symbol D. In this example, image light IL with a polarization direction parallel to the orientation direction of the dye or pigment D is projected, and the image light IL is incident on the light-transmitting switching section (924a, 924b). A portion of the image light IL is Fresnel reflected at the incident surface and directed towards the driver. The driver can then see a virtual image corresponding to the displayed image superimposed on the scenery. Furthermore, the polarized component of the external light SL, which is perpendicular to the orientation direction of the dye or pigment D, is transmitted through the light transmission / blocking switching section (924a, 924b).

[0036] The image light IL and the ambient light SL that passes through the light-transmitting and light-blocking switching sections (924a, 924b) have a polarization component tilted at approximately 45° with respect to the x-axis. Therefore, even when the driver wears polarized sunglasses as a countermeasure against ambient light directly entering the vehicle, they can still see the virtual image corresponding to the scenery and the displayed image. Here, wearing polarized sunglasses reduces the brightness of the ambient light SL that passes through the windshield 3 (including the ambient light SL that passes through the light-transmitting and light-blocking switching sections (924a, 924b)) and the brightness of the image light IL by about half, so there is no discomfort when wearing sunglasses. In other words, the darkness that the driver perceives when wearing polarized sunglasses is the same for the scenery seen through the windshield 3 (including the scenery seen through the light-transmitting and light-blocking switching sections (924a, 924b)) and the virtual image 8. As a result, the contrast within the driver's field of view remains constant before and after wearing polarized sunglasses, and there is no discomfort when wearing polarized sunglasses.

[0037] Furthermore, the component of the image light IL that is not reflected by Fresnel at the incident surface of the light-transmitting switching section (924a, 924b), that is, the image light IL that enters the interior of the light-transmitting switching section (924a, 924b), is absorbed by the oriented dye or pigment. This suppresses the double image that occurs when the image light IL is reflected by Fresnel on the back surface (outside surface) of the windshield 3.

[0038] Referring to Figures 10A and 10B, an example of the semi-transparent state of the light-transmitting switching section will be explained. In this example, the orientation direction of the light-transmitting switching section (924a, 924b) is different from that described above. That is, in the semi-transparent area of ​​the light-transmitting switching section (924a, 924b), the dye or pigment within the light-transmitting switching section (924a, 924b) is oriented in a direction perpendicular to the xy plane and along the z axis direction corresponding to the longitudinal direction of the vehicle. In the same figure, the dye or pigment is indicated by the symbol D. In this example, the transmittance increases as the occupancy rate of the dye or pigment D in the xy plane decreases, making the scenery viewed through the light-transmitting switching section (924a, 924b) easier to see. The ambient light SL is transmitted through the light-transmitting switching section (924a, 924b) with reduced light intensity while remaining randomly polarized.

[0039] The image light IL is projected onto the light-transmitting / light-blocking switching section (924a, 924b), and a portion of the image light IL is Fresnel-reflected at the incident surface of the light-transmitting / light-blocking switching section (924a, 924b) and directed towards the driver. The driver can then see a virtual image corresponding to the displayed image superimposed on the scenery. The polarization direction of the image light IL is arbitrary and can be randomly polarized, but by projecting S-polarized image light IL, a high reflectivity can be obtained at the interface of the light-transmitting / light-blocking switching section (924a, 924b), making the image brighter. However, a portion of the image light IL passes through the light-transmitting / light-blocking switching section (924a, 924b) and is reflected on the back surface (outside the vehicle) of the windshield 3, resulting in a double image. Therefore, it is desirable to take measures to prevent double images, for example, using wedge glass.

[0040] As described above, even when the driver wears polarized sunglasses as a countermeasure against external light directly entering the vehicle, the driver can still see the virtual image corresponding to the displayed image, except when the image light IL is S-polarized. Here, when the image light IL is randomly polarized, circularly polarized, or linearly polarized at approximately 45° with respect to the x and y axes, wearing polarized sunglasses reduces the brightness of the external light SL that passes through the windshield 3 (including the external light SL that passes through the light-transmitting switching parts (924a, 924b)) and the brightness of the image light IL by about half, so there is no discomfort when wearing sunglasses. In other words, the darkness that the driver perceives when wearing polarized sunglasses is the same for the scenery seen through the windshield 3 (including the scenery seen through the light-transmitting switching parts (924a, 924b)) and the virtual image 8, so the contrast in the driver's field of view remains constant before and after wearing polarized sunglasses, and there is no discomfort when wearing polarized sunglasses. By arranging a light-transmitting / light-blocking switching section or a light-blocking section, the double image caused by Fresnel reflection of the image light on the back surface (outside the vehicle) of the windshield can be suppressed, improving the visibility of the content and enabling a more suitable display device.

[0041] Next, an example of the vehicle configuration will be described with reference to Figure 11. Note that the vehicle may be equipped with a light-transmitting / light-blocking switching unit. In the configuration example in Figure 11, the vehicle is equipped with a light-transmitting / light-blocking switching unit (924a or 924b), and the vehicle's controller or control device controls the light-transmitting / light-blocking switching unit (924a, 924b).

[0042] As shown in Figure 11, the vehicle is equipped with a controller 100 or a control device. The controller 100 or control device (sometimes referred to as controller 100) acquires vehicle information using connected devices such as cameras and various sensors. Note that the various devices in Figure 11 can be deleted, other types of devices added, or replaced with other types of devices as appropriate. For example, the controller 100 of vehicle 2 may also have a function related to the control of the display device 1.

[0043] The vehicle speed sensor 901 detects the speed of 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.

[0044] 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 whether the engine is ON or OFF and is used to generate ON / OFF information as detection results.

[0045] 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 that represents the attitude and behavior of the vehicle 2.

[0046] The temperature sensor 914 detects the temperature inside and outside the vehicle and is used to generate temperature information as the detection result.

[0047] The vehicle-to-infrastructure wireless transceiver 915 generates vehicle-to-infrastructure communication information through vehicle-to-infrastructure communication between 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 vehicle 2 and other surrounding vehicles. The wired wireless communication unit 917 for mobile terminal-to-vehicle communication is a device that acquires information from devices connected to the LTE (Long Term Evolution) network (e.g., WiFi devices) via wired or wireless communication. 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.

[0048] 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.

[0049] On the other hand, the external camera 920 captures the surrounding environment, such as the front and rear of 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 also includes, for example, a dashcam that records the driving situation in video.

[0050] 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.

[0051] 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 switch 911 is used to generate driver operation information for steering wheel switches, etc.

[0052] Furthermore, the video generation unit 910 generates video information based on the vehicle information 4 acquired by the controller 100 of the vehicle 2.

[0053] The raindrop sensor 923 detects raindrops adhering to the windshield 3 of the vehicle 2, and the controller 100 acquires information about the raindrops as a result of the detection. The light transmission / light blocking switching units (924a, 924b) are configured to control the transmission and blocking of light, as described above. For example, the controller 100 can control the operation of the light transmission / light blocking switching units (924a, 924b) based on the control processing described later.

[0054] Next, an example configuration of the display device will be described with reference to Figures 12 and 13. Note that the display device 1 may be equipped with a light-transmitting / light-shielding switching unit. In the configuration examples of Figures 12 and 13, the display device is equipped with a light-transmitting / light-shielding switching unit (924a or 924b), and the processor of the display device (MCU 1010 in these examples) controls the light-transmitting / light-shielding switching unit (924a, 924b).

[0055] In Figure 12, the display device 1 includes, for example, a microcontroller (MCU) 1010 mounted on a wiring board, a non-volatile memory 1011, a volatile memory 1012, a video processing unit 1013, a communication processing unit 1014, a display driver 1021, and a light source drive unit 1022, etc. In the example in Figure 12, the communication processing unit 1014 receives and transmits the main vehicle information 4, but it may also function as the control unit of the display device 1. The video processing unit 1013 receives video information or video data generated by the video generation unit 910 of the vehicle 2's controller 100. The video processing unit 1013 does not generate video, but processes the video received from the vehicle 2. The processing performed by the video processing unit 1013 includes processing such as distortion correction and conversion (e.g., decoding) of the video.

[0056] In Figure 13, similar to Figure 12, the system includes a microcontroller (MCU) 1010, non-volatile memory 1011, volatile memory 1012, communication processing unit 1014, video processing unit 1015, display driver 1021, and light source drive unit 1022, etc., mounted on a wiring board. However, in the example of Figure 13, the video processing unit 1015 has the function of a video generation unit 910, and instead of receiving video information, it generates video information using acquired information (for example, vehicle information 4). Furthermore, the video processing unit 1015 can perform processing such as distortion correction and conversion on the generated video information.

[0057] As is widely known, the MCU1010 includes a processor such as a CPU (Central Processing Unit), memory, and various peripheral functions. Therefore, each block other than the MCU1010 may be mounted within the MCU1010 as appropriate. Furthermore, the display device 1 is not limited to implementation using the MCU1010, but may also be implemented using an ECU or other semiconductor devices. The control structure shown in Figures 12 and 13 may be, for example, a control unit mounted inside the housing of the display device 1, or a control unit mounted outside the housing.

[0058] In the example shown in Figure 12, the MCU 1010 receives video information via the communication processing unit 1014, for example, via FPD-Link III or GMSL. The MCU 1010 may also perform processing such as distortion correction and conversion on the received video information as a function of the video processing unit 1013. The video processing unit 1013 is mainly implemented by the CPU of the MCU 1010 reading and executing a program stored in the non-volatile memory 1011 or volatile memory 1012.

[0059] In the example shown in Figure 13, the MCU 1010 receives vehicle information 4 via the communication processing unit 1014, for example, via CAN or in-vehicle Ethernet. The MCU 1010, as a function of the video processing unit 1015, can generate video data for the video display unit 200 based on the vehicle information 4, etc. The video processing unit 1015 is mainly implemented by the CPU of the MCU 1010 reading and executing a program stored in the non-volatile memory 1011 or volatile memory 1012.

[0060] Specifically, the video processing units (1013, 1015) process video data that determines the content of the display image to be projected onto the display area 5, such as in Figure 1, based on the acquired information. The display driver 1021 drives each display element (pixel) included in the display panel 11 based on the video data. As a result, the image forming unit 10 or image forming unit 10 creates and displays an image to be projected onto the display area 5 based on the video data.

[0061] Specifically, distortion correction corrects the image distortion caused by the curvature of the windshield 3 when the image from the display device 1 is projected onto the display area 5, as shown in Figure 1. The display driver 1021 then drives each display element (pixel) included in the display panel 11 based on the corrected image data. As a result, the image forming unit 10 or image forming unit 10 creates and displays an image for projection onto the display area 5 based on the corrected image data.

[0062] Furthermore, the light source drive unit 1022 can adjust the light source, and the light source drive unit 1022 adjusts the brightness of the light source 20 in the image forming unit PGU1 or the image forming unit PGU1. Based on the vehicle information 4 received via the communication processing unit 1014, the light source 20 is controlled using the light source drive unit 1022, which is a driver used to drive the light source.

[0063] 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 panel 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 in the image forming unit PGU1 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.

[0064] The non-volatile memory 1011 primarily stores programs executed by the CPU within the MCU 1010, setting parameters used for processing in various parts of the MCU 1010, and predefined audio and video data.

[0065] The volatile memory 1012 primarily stores acquired information and various data used in the processing of each part within the MCU 1010 as needed. The communication processing unit 1014 is a device with a communication interface implemented, and communicates with the outside of the display device 1 based on communication protocols such as CAN or LIN. The communication processing unit 1014 may be integrated with the vehicle information acquisition unit.

[0066] Each part of the control device in Figures 12 and 13 may be implemented using dedicated circuits such as FPGAs (Field Programmable Gate Arrays) as appropriate. In this embodiment, the device has a configuration with a non-volatile memory 1011 and a volatile memory 1012, but the above processing may be performed using a single memory. Figure 13 shows the display device's video processing unit creating an image based on information acquired from the vehicle, while Figure 12 shows the acquisition of an image from the vehicle.

[0067] Next, the image forming unit will be described in detail. The image forming unit PGU1 displays an image based on video data and projects the image light of the displayed image. The image forming unit PGU1 comprises a light source 20 and a display panel 11 such as a liquid crystal display (LCD) having an image display element.

[0068] The image forming unit PGU1 projects the image light of the image formed on the display panel 11 using light emitted from the light source 20 (in other words, light from the light source). The light source 20 is typically composed of an LED (Light Emitting Diode).

[0069] The display panel 11 creates an image based on the video data and displays it on the display screen of the display panel 11. In this embodiment, the video data is described as video data input from the video processing units (1013, 1015). The display panel 11 modulates the transmittance of light from the light source 20 for each pixel according to the video data, thereby forming an image for projection onto the display area 5, and projects it as video light (in other words, projected light).

[0070] 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 to form a real 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 electro-mechanical system may be used.

[0071] 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. The light source 20 functions as a backlight light source for 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.

[0072] The backlight section is constructed using light sources 20, etc. A specific example of the backlight section's configuration will be described later.

[0073] The image light emitted from the display panel 11, in other words, the projected light, is directed toward the display area 5 of the windshield 3. Therefore, the user of the display device 1 can, for example, perceive this image light as a virtual image. As a result, the driver can, for example, perceive the image light projected onto the display area 5 as a virtual image beyond the transparent windshield 3, superimposed on the scenery outside the vehicle (for example, roads, buildings, people, etc.). The projected image can be anything from road signs, the current speed of the vehicle, to various information added to objects in the scenery. As a result, for example, augmented reality (AR) functions can be realized that add various information to objects in the scenery and display it.

[0074] Next, an example of control of the light-transmitting / light-blocking switching unit will be described with reference to Figures 14-15. The main processing is performed by a processor that controls the light-transmitting / light-blocking switching unit (924a, 924b). The processor may be the vehicle's controller 100, or the MCU or control unit of the display device. Furthermore, the display device or vehicle may also be equipped with a processor that controls the light-transmitting / light-blocking switching unit.

[0075] As shown in Figure 14, when control of the light transmission / blocking switching unit (924a, 924b) is initiated, the processor makes a determination regarding determination item A (S01). Then, according to the determination result, the processor controls in either the first mode or the second mode (S02, S03) and terminates the process.

[0076] In the first mode, part or all of the display area is in a light-shielding state. When part of the display area is in a light-shielding state, the area outside the shielded portion becomes semi-shielded (i.e., semi-transparent), thereby ensuring both a clear view for the driver and visibility of the display. In addition, in the first mode, it is possible to concentrate and display information in a portion of the light-shielding area within the display area. For example, depending on the surrounding conditions and vehicle information while driving, such as driving speed, navigation information, driving on ordinary roads, or driving on highways, the area to be shielded is adjusted from the entire display area to a portion of the display area, and the information to be displayed is concentrated in the shielded portion. When the information to be displayed is concentrated in the shielded portion, the size of the display content may be reduced, or lower-priority information may be deleted, and only the more important display content may be displayed. In the first mode, for example, the light-shielding switching unit (924a, 924b) may control the area to be shielded according to the shape, outline, and color of the display content, thereby making part of the display area in a light-shielding state. Furthermore, for example, the light-transmitting / light-blocking switching section (924a, 924b) may be set to a light-blocking state only at the incident position of the video light and its surroundings.

[0077] The choice of whether to partially or entirely shade the display area may be controlled automatically. In this case, the processor may choose, for example, to shade part or all of the display area depending on the projected content. For example, when projecting video content or navigation information, the entire display area may be shaded. When projecting still image content such as sign information, only a part of the display area (for example, only the area around the content) may be shaded. Alternatively, the user may set the shaded portion of the display area themselves.

[0078] In the second mode, the entire display area becomes semi-transparent (i.e., semi-illuminated). In this state, the driver can view the content superimposed on the scenery outside the vehicle.

[0079] Referring to Figure 15, an example of judgment item A related to S01 described above will be explained in detail. In the judgment example in the figure, if judgment condition 1 is met, the first mode is selected (S02), and if judgment condition 2 is met, the second mode is selected (S03).

[0080] The processor, for example, determines in S01 whether the user has selected either the first or second mode (Determination Example 1). That is, if the processor receives an instruction to make part or all of the display area dark, it performs control based on the first mode, and if it receives an instruction to make the entire display area semi-transparent, it performs control based on the second mode. For example, when a driver wants to drive while checking the surrounding conditions, the driver can, as an example, make it easier to obtain the surrounding conditions by making the display area semi-transparent (i.e., second mode). Alternatively, the driver can make it easier to obtain the surrounding conditions by making only a part of the display area dark (i.e., first mode) and consolidating the information there. In this case, the information may be displayed in a small size, and visibility can be easily obtained by using a black background. Also, when a driver wants to drive while looking at navigation information or speed information, the driver can, as an example, make the display area dark. Here, the driver can, as an example, make the entire display area dark.

[0081] For example, in S01, the processor determines whether the vehicle's battery level is greater than or less than a threshold (Determination Example 2). That is, the processor determines whether the vehicle's battery level is less than or equal to a threshold. If the battery level is low, power saving can be achieved by reducing the image brightness as a light-shielding state.

[0082] The processor, for example, in S01, determines whether the brightness outside the vehicle is greater than or less than a predetermined threshold (Determination Example 3). That is, the processor determines whether the brightness outside the vehicle is greater than or less than a threshold. The processor can use information obtained using, for example, the illuminance sensor 905. When it is bright outside the vehicle, the visibility of the image can be ensured by setting it to a light-blocking state. In addition, by setting it to a light-blocking state, the temperature rise due to sunlight incidence can be suppressed, and the product life can be extended. When it is dark outside the vehicle (such as at night), the forward visibility of the driver can be ensured by setting it to a semi-transparent state.

[0083] The processor, for example, in S01, determines whether the vehicle's speed is greater than or less than a threshold (Determination Example 4). In other words, the processor determines whether the vehicle's speed is greater than or less than a threshold. The processor can use information obtained using, for example, the vehicle speed sensor 901. When driving at low speeds, visibility of the surrounding environment is important, so the processor makes the entire display area semi-transparent. For example, when driving at low speeds in urban areas, the processor makes the entire display area semi-transparent to prioritize ensuring a clear view of the driver's field of vision. On the other hand, when driving (for example, when driving on ordinary roads or highways), the processor makes part or all of the display area shaded.

[0084] The processor, for example, determines in S01 whether the vehicle's wipers are operating (Determination Example 5). In rainy weather, raindrops scatter light (e.g., ambient light, headlights of oncoming vehicles), reducing the visibility of the image. Therefore, a light-blocking state is created to improve image visibility.

[0085] The processor, for example, determines in S01 whether or not raindrops have been detected (Determination Example 6). The processor can use information obtained using, for example, the raindrop sensor 923. Similar to the case of Determination Example 5, since light is scattered by raindrops and the visibility of the image is reduced, the image visibility is improved by creating a light-shielding state.

[0086] The processor, for example, in S01, determines whether the vehicle's ignition switch or the vehicle's power is OFF (Determination Example 7). When the vehicle is not in use (for example, when the vehicle's ignition is OFF, or when the power switch for enabling electric vehicles to run is OFF), it is set to a light-shielding state to suppress deterioration of the display device due to external light (sunlight).

[0087] For example, in S01, the processor determines whether an object (pedestrian, obstacle, etc.) is within a specified range around the vehicle (Determination Example 8). The processor can use information acquired using, for example, a distance measuring sensor 907 (e.g., a sonar sensor, millimeter-wave radar). Alternatively, for example, an infrared sensor 908 may be used. When an object is detected around the vehicle, the processor enters a semi-transparent state to ensure visibility. On the other hand, when no object is detected around the vehicle, the processor enters a light-shielding state.

[0088] Next, with reference to Figures 16-20, a specific structural example of the display device (more specifically, the image forming unit 10) will be described.

[0089] Figure 16A shows an example of the configuration of an image forming unit. The display device has an image forming unit 10, which comprises a display panel 11 having an image display element and a light source device 12 that emits light to the display panel 11. The display device uses the light emitted from the light source device 12 (in other words, light from the light source) to project the image light of the image formed on the display panel 11 onto a projection member. The display device may also be called a projection-type display device. The display panel 11 forms an image for projection onto the projection member based on image data and emits it as image light (in other words, projected light). The display panel 11 may also be a liquid crystal display (LCD). In this embodiment, the projection member or projection unit that projects the image light is the display area 5 of the windshield 3, but is not limited to the display area 5 of the windshield 3.

[0090] On the other hand, 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 to form a real 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 electro-mechanical system may be used.

[0091] The light source device 12 comprises a light source 20, a reflective mirror 21 (optical component), and a reflective optical element 23a. The light source device 12 may also include a polarization conversion element 22 and a diffuser plate 25. The light source 20 typically includes an LED (Light Emitting Diode) and may be referred to as the backlight section. The light source 20 consists of one or more LED light sources, and the multiple LED light sources may be arranged in a single row, in two or more rows, or arranged according to the design.

[0092] The reflective mirror 21 is used to reflect light from the light source 20 and adjust it to be approximately parallel or 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. In this embodiment, the reflective mirror 21 is used for explanation, but the optical component may also be a collimating lens.

[0093] 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. In this embodiment, the polarization conversion element 22 aligns the polarization of the light emitted from the light source 20, thereby improving the efficiency of image projection.

[0094] The reflective optical element 23a may also be called a light guide or light guide body. The reflective optical element 23a is configured to adjust the angle of incidence of light rays to the display panel 11, and may be a prism sheet, for example. In this embodiment, the reflective optical element 23a has a light reflecting portion 24 having a prism shape (a jagged shape), and light rays incident on the light reflecting portion 24 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 light reflecting portion 24, the inclination of the reflective surface, the surface roughness, etc. Furthermore, the reflective optical element 23a is, for example, a resin member having a prism shape, and a reflective film or the like is coated on the prism-shaped portion that becomes the reflective surface. Therefore, in the structure of Figure 16A, 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.

[0095] Figure 16B shows an enlarged view of the light-reflecting portion 24 of the reflective optical element 23a. The light-reflecting portion 24 has a number of reflective surfaces and connecting surfaces formed alternately in a sawtooth pattern. Light incident on the reflective optical element 23a is reflected on each reflective surface and directed upward, and further adjusted to a predetermined light distribution characteristic via the diffuser plate 25 before being incident on the display panel 11. The elevation angles α1a, α2a, α3a, α4a… of the reflective surfaces are arbitrarily set to obtain a predetermined light distribution characteristic, while the relative angles β1a, β2a, β3a, β4a… between the reflective surfaces and connecting surfaces are set to a constant angle regardless of location, more preferably an angle of 90 degrees or more (βna≧90°). When manufacturing the reflective optical element 23a by injection molding, setting the relative angle βna to 90 degrees or more facilitates mold processing of the reflective surfaces and connecting surfaces.

[0096] By appropriately setting the lengths and ratios of the connecting surfaces Lc1a, Lc2a, Lc3a... and the reflective surfaces Lr1a, Lr2a, Lr3a..., it becomes possible to realize a light source unit in which the illumination range of the light reflected by the reflective optical element 23a can be changed to the required size (surface size) for a device such as a display panel 11. Furthermore, by appropriately adjusting the ratio Lr / Lc, it is possible to partially strengthen or weaken the reflected light. For example, the ratio Lr / Lc is adjusted according to the intensity distribution of the light incident on the light reflection section 24. More specifically, in areas where the intensity of the incident light is strong in the light reflection section 24, the ratio Lr / Lc is reduced, that is, the elevation angle αna of the reflective surface is set in fine increments, thereby precisely controlling the direction of light reflection and uniformly adjusting the brightness distribution of the light incident on the display panel 11.

[0097] Figure 17 shows a modified example of the display device shown in Figure 16A. According to the reflective optical element 23b in Figure 17, as shown in Figure 16B, the ratio Lrb / Lcb between the length Lrb of the slope projected onto a plane perpendicular to the emission direction of the multiple reflective surfaces of the light reflection section 232 and the length Lcb of the slope projected onto a plane perpendicular to the emission direction of the connecting surfaces connected to the reflective surfaces is varied depending on the location. Therefore, by appropriately setting the lengths and ratios of the connecting surfaces Lcb1, Lcb2, Lcb3... and the reflective surfaces Lrb1, Lrb2, Lrb3..., the length of the light emission section 233 in the optical axis direction can be freely changed. This makes it possible to realize a light source unit in which the size (surface size) of the light emission section 233 can be changed to the size (surface size) required for a device such as a display panel 11, relative to the light incidence section 231.

[0098] Furthermore, similarly to the above, by appropriately adjusting the ratio Lr / Lc, it is possible to partially strengthen or weaken the reflected light. For example, the ratio Lr / Lc is adjusted according to the intensity distribution of the light incident on the light reflection section 232. More specifically, in areas of the light reflection section 232 where the intensity of the incident light is strong, the ratio Lr / Lc is reduced, that is, the elevation angle αnb of the reflection surface is set in fine increments, thereby precisely controlling the direction of light reflection and making it possible to uniformly adjust the brightness distribution of the light incident on the display panel 11.

[0099] As shown in Figure 18, the image forming unit 10 may, for example, be an edge-type backlight structure. Multiple light sources 20 are arranged in the depth direction of the paper so as to face the side surface of the light guide 23, and the light guide 23 (reflective optical element) is placed on the back side of the display panel 11, and the light guide 23 is provided with multiple reflective dots 27 that emit light toward the display panel 11. The reflective dots 27 diffusely reflect the guided light, thereby achieving uniform illumination. The reflective dots 27 are formed on the light guide 23 by printing white ink, forming an uneven shape, forming a groove pattern, etc. In order to obtain uniform illumination at positions close to and far from the light source 20, the reflective dots 27 may be formed so that the density of reflective dots 27 increases as they move further away from the light source 20. A reflective sheet 28 is also provided so as to face the display panel 11, and the light guide 23 is placed between the display panel 11 and the reflective sheet 28. In this case, the light that is not diffusely reflected by the reflective dots 27 and is emitted from the light guide 23 in the opposite direction to the display panel 11 is reflected by the reflective sheet 28 and incident on the display panel 11 via the light guide 23. In this example, a diffuser plate 25 is provided between the display panel 11 and the light guide 23, but the diffuser plate 25 may be omitted. The diffuser plate 25 may also be placed downstream of the display panel 11. In this example, a reflective sheet 28 is provided to cause light to incident on the light guide 23, but the reflective sheet 28 may be omitted.

[0100] As shown in Figure 19, the image forming unit 10 may, for example, be a direct-lit backlight structure. A plurality of light sources 20 are arranged below the display panel 11. These multiple light sources 20 can be configured, for example, as an LED array relating to micro-LEDs or mini-LEDs. In this example, the plurality of light sources 20 are provided on a substrate, and a reflective sheet 28 is provided on the surface of the substrate facing the display panel 11. A diffuser plate 25 is placed between the display panel 11 and the reflective sheet 28. A plurality of reflective dots 27 are formed on the diffuser plate 25 so as to face the light sources 20. With this configuration, the light directly above the light sources 20, which tend to become high-brightness spots, is reflected by the reflective dots 27 and then reflected by the reflective sheet 28 on the substrate. This makes it possible to uniformly adjust the brightness distribution of the light incident on the display panel 11. The reflective dots 27 are formed on the diffuser plate 25 by printing white ink, forming uneven shapes, forming groove patterns, etc. Note that the reflective sheet 28, diffuser plate 25, and reflective dots 27 may be omitted. Alternatively, multiple diffusers 25 that do not form reflective dots 27 may be used.

[0101] As shown in Figure 20, the image forming unit 10 may, for example, have a fly-eye integrator structure. Between the display panel 11 and the light source 20, a lens array 31, a fly-eye lens 32, and a focus lens 33 are arranged in order of the direction of light propagation. The lens array 31 makes the light (LED light) emitted by multiple light sources 20 (LEDs) into approximately parallel light. The fly-eye lens 32 improves the uniformity of the illumination surface by forming an image of the light-emitting element. Note that a configuration in which two fly-eye lenses are combined may be used. That is, a configuration in which the light beam is divided by the first fly-eye lens and each light beam is guided to the illumination area by the second eccentric fly-eye lens may be used. The focus lens 33 is configured to concentrate the light from the light source 20 onto the illumination surface.

[0102] Based on the above description, as an example, a display device is provided comprising a light source 20, a display panel 11, and a light-transmitting / light-blocking switching unit (924a, 924b). That is, this display device is a device mounted on a vehicle 2. Light from the light source 20 is incident on the display panel 11. Image light projected by the display panel 11 is incident on the light-transmitting / light-blocking switching unit (924a, 924b). The light-transmitting / light-blocking switching unit (924a, 924b) is positioned in front of the driver and can switch between a light-blocking state and a semi-transparent state in part or all of the area into which the image light is incident (the area corresponding to the display area 5). Furthermore, for example, this display device may include a processor (for example, the vehicle's controller 100, or the display device's MCU) that controls the switching between the light-blocking state and the semi-transparent state of the light-transmitting / light-blocking switching unit (924a, 924b). Then, using this processor, for example, the processing described with reference to Figures 14-15 may be performed. Furthermore, this processor may be used to perform the processing described later (the processing shown in Figure 21).

[0103] 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.

[0104] A light-blocking / transmittance switching section containing a photochromic dye may be used to switch between a light-blocking state and a semi-transmittance state. In this case, the transmittance changes naturally as the dye develops or fades color depending on the amount of ultraviolet or visible light. When it is bright outside the vehicle, the light-blocking / transmittance switching section is in a light-blocking state, and when it is dark outside the vehicle (at night, in a tunnel, etc.), it is in a semi-transmittance state. In other words, the transmittance of this light-blocking / transmittance switching section changes naturally according to the brightness outside the vehicle. Therefore, it is possible to switch between a light-blocking state and a semi-transmittance state without control by a processor. By arranging a light-blocking / transmittance switching section or a light-blocking section, double images caused by Fresnel reflection of image light on the back surface (outside the vehicle) of the windshield can be suppressed, improving the visibility of the content and enabling a more suitable display device.

[0105] In the determination shown in Figures 14 and 15, the processor may, for example, determine whether vehicle 2 is in autonomous driving mode (or cruise control mode). When in autonomous driving or cruise control mode, the entire display area is made shaded to prioritize vehicle information (such as driving conditions) over the driver's field of view, and the information can be displayed in a larger size. In addition, video content can be displayed on a larger screen. From the viewpoint of displaying information in a larger size, for example, the light-transmitting / light-blocking switching section may be provided across the entire lower part of the windshield, as shown in Figure 3A, etc. That is, the light-transmitting / light-blocking switching section may be provided on the lower part of the windshield 3, extending from left to right.

[0106] The orientation of dyes or pigments can be controlled by appropriate methods. For example, a configuration may be provided to apply an electric field in a predetermined direction. This configuration may be controlled by a processor (e.g., a vehicle controller 100 or an MCU of a display device).

[0107] Whether the light-transmitting / light-blocking switching section of the display area 5 in Figure 1 is in a light-blocking or semi-transmitting state is determined based on the transmittance of the light-transmitting / light-blocking switching section. If the transmittance is 10% or less, it is determined to be in a light-blocking state. If the transmittance of the light-transmitting / light-blocking switching section is 10% or less, the background brightness of the projected image is sufficiently dark relative to the brightness of the image projected onto the display area 5, and the driver can clearly see the virtual image 8. In addition, in such a case, the incidence of ambient light on the display panel can be suppressed, and the temperature rise and deterioration of the display panel can be suppressed.

[0108] In the first mode, part or all of the display area 5 is in a light-shielding state, while in the second mode, the entire display area 5 is in a semi-light-shielding state. When switching from the first mode to the second mode, the transmittance of the light-shielding switching section increases, meaning the background brightness of the projected image becomes brighter. This increases the brightness of the projected image, ensuring the visibility of the virtual image 8. When switching from the second mode to the first mode, the brightness of the projected image is reduced, and the projected image is switched to a color tone that is easily visible against a black background. More specifically, in the second mode, the light-shielding switching section is semi-transparent, so in principle, black cannot be used for image display. In contrast, in the first mode, the light-shielding switching section is in a light-shielding state, meaning the background of the projected image is black, allowing black to be used for image display. In other words, when switching from the second mode to the first mode, the brightness and color tone of the projected image are adjusted to display a highly visible virtual image 8. On the other hand, at night, even when the light-transmitting / light-blocking switching section is in a semi-transparent state (second mode), the background brightness of the projected image is dark, so when switching from the second mode to the first mode, it is not necessary to reduce the brightness of the projected image. Brightness adjustment of the projected image is performed, for example, by adjusting the duty cycle in PWM (Pulse Width Modulation) control in the case of an LED light source. Increasing the duty cycle increases the brightness of the projected image, and decreasing the duty cycle decreases the brightness of the projected image.

[0109] The light-transmitting / light-blocking switching units (924a, 924b) may be electrically connected to the vehicle 2 or to the display device 1. When the light-transmitting / light-blocking switching units (924a, 924b) are electrically connected to the vehicle 2, the vehicle 2 controls the light-transmitting / light-blocking switching units (924a, 924b). When the light-transmitting / light-blocking switching units (924a, 924b) are electrically connected to the display device 1, they may be controlled by the control unit of the display device 1 or controlled by the vehicle 2's controller via the communication processing unit 1014 of the display device 1.

[0110] Figure 21 is a flowchart showing an example of the control of the light-transmitting / light-blocking switching unit for each video. As shown in Figure 21, when control of the light-transmitting / light-blocking switching unit (924a, 924b) is started, step S001 determines the mode corresponding to the video. Depending on the determination result, either the first mode or the second mode is selected (S002, S003), and the process ends.

[0111] When displaying images containing text or characters, the background of the display area is made opaque so that the small characters can be seen. Alternatively, if step S001 determines that the image contains text or characters, select the first mode, which makes the characters easier to identify, and proceed to step S002. If the image does not contain text or characters, proceed to step S003 (second mode).

[0112] Furthermore, when the vehicle is stationary, the light-transmitting / light-blocking switching section (924a, 924b) is set to the light-blocking state to display a more visible image. Here, "stationary" refers to the state until the parking shift and brakes are released. When the parking shift and brakes are released, in other words, when vehicle 2 starts moving, it is desirable to switch the light-transmitting / light-blocking switching section (924a, 924b) from the light-blocking state to the semi-transparent state to ensure the driver's field of vision is clear so that the area around the vehicle is clearly visible.

[0113] Based on the above description, as an example, a display system is provided comprising a light source 20, a display panel 11, and a light-transmitting / light-blocking switching unit (924a, 924b). That is, this display system is a system mounted on a vehicle 2. Light from the light source 20 is incident on the display panel 11. Image light projected by the display panel 11 is incident on the light-transmitting / light-blocking switching unit (924a, 924b). The light-transmitting / light-blocking switching unit (924a, 924b) is positioned in front of the driver and can switch between a light-blocking state and a semi-transparent state in part or all of the area into which the image light is incident (the area corresponding to the display area 5). Furthermore, for example, this display device may include a processor (for example, the vehicle's controller 100, or the display device's MCU) that controls the switching between the light-blocking state and the semi-transparent state of the light-transmitting / light-blocking switching unit (924a, 924b). Then, using this processor, for example, the processing described with reference to Figures 14-15 and 21 may be performed.

[0114] In the technology according to the embodiment of the present invention, by arranging a light-transmitting switching unit that switches between a light-shielding state and a semi-transparent state in part or all of the area into which the image light is incident, the visibility of the content can be improved, a more suitable display device can be realized, and a display device that contributes to supporting safe driving can be provided, thereby preventing traffic accidents. This contributes to "Goal 3: Good Health and Well-being" of the United Nations' Sustainable Development Goals (SDGs). [Explanation of symbols]

[0115] 1 Display device 10 Image forming unit 11 Display Panel 12 Light source device 20 light source 21. Reflective mirror (optical component) 22 Polarization conversion element 23 Light guide 23a Reflective optical element 23b Reflective optical element 24 Light reflecting part 25 Diffuser 27 Reflective dots 28 Reflective sheet 31 Lens Array 32 Fly-eye lenses 33 Focus Lens 923a Transmittance / Shading Switching Section 923b Transmittance / Shading Switching Section

Claims

1. A display system installed in a vehicle, Light source and A display panel into which light from the aforementioned light source is incident, A light-transmitting / light-blocking switching section into which the image light projected by the display panel is incident, Equipped with, The light-transmitting / light-blocking switching unit switches between a light-blocking state and a semi-transmitting state in part or all of the area into which the image light is incident, depending on the projected image. Display system.

2. A display system according to claim 1, A display system that, when the aforementioned image contains text or characters, sets the light-shielding switching unit to a light-shielding state.

3. A display system according to claim 1, When the vehicle is stopped, the light-transmitting / light-blocking switching section is in the light-blocking state. Display system.

Images