Display device and display system

Abstract

To provide a display device and a display system capable of selectively functioning as a mirror and performing satisfactory antiglare.SOLUTION: A display device comprises, between a liquid crystal display 11 for displaying a video and an optical device 12 arranged in a position where video light emitted from the liquid crystal display 11 passes, including a reflection polarization plate 121, and capable of controlling a reflection rate / transmittance of the incident light, an AG layer 15 (a2, b2)(Anti-glare layer: antiglare layer). A phase of light reflected by a color filter of the liquid crystal display 11 becomes unaligned by dispersion in the AG layer 15. Therefore, a degree of interference is reduced and an iridescent color image is inhibited from appearing by interference light. Since external light dispersed and scattered by the AG layer 15 and reflectance of the external light have no polarization property, most of components travelling outward is reflected by the reflection polarization plate 121, which inhibits an area around bright reflection image from being seen cloudy.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a display device that can be selectively made to function as a mirror. [Background technology]

[0002] As a display device that can selectively function as a mirror, a display device in which an optical device capable of controlling the reflectance / transmittance of incident light is arranged in a position opposite the display surface of a liquid crystal display is known (for example, Patent Document 1). Here, this optical device controls the reflectance / transmittance by changing the ratio at which the incident light is divided into reflected light and transmitted light, and increasing the reflectance reduces the transmittance, and decreasing the reflectance increases the transmittance.

[0003] Also, as a display device that can selectively function as a mirror, a display device is known in which a half mirror that partially reflects external light is disposed in a position opposite to the display surface of the image display device, and an anti-glare layer is provided on the surface of the half mirror on the side where external light enters (for example, Patent Documents 2 and 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6624193 [Patent Document 2] JP 2020-118992 A [Patent Document 3] JP 2008-191310 A Summary of the Invention [Problem to be solved by the invention]

[0005] When a display device using the optical device capable of controlling the reflectance / transmittance of external light as described above is installed in an automobile and functions as a mirror for viewing behind the automobile, it is conceivable that anti-glare can be achieved by reducing the reflectance of the optical device when there is strong light coming from behind, such as the headlights of a following vehicle.

[0006] In this case, the transmittance of the optical device increases during anti-glare operation, so the proportion of external light that passes through the optical device and reaches the display surface of the liquid crystal display increases. Meanwhile, the external light that reaches the display surface is reflected by the display surface and passes through the optical device again to be emitted to the outside, but this emitted light contains interference light caused by diffraction by the color filter of the liquid crystal display. Therefore, if anti-glare is performed by reducing the reflectance of the optical device, a problem occurs in that rainbow-like images caused by interference light that do not actually exist behind the vehicle appear around the bright reflected image.

[0007] Therefore, it is conceivable to apply the anti-glare configuration of the display device using the above-mentioned half mirror and provide an anti-glare layer on the surface of the optical device whose reflectance / transmittance can be controlled on the side on which external light enters, thereby achieving anti-glare.

[0008] However, doing so causes the problem that when the optical device is controlled to have a high reflectance to function as a mirror, the anti-glare layer scatters and diffuses light, causing the areas around the bright reflected image to appear cloudy.

[0009] Therefore, an object of the present invention is to provide good, problem-free anti-glare performance in a display device in which an optical device capable of controlling the reflectance / transmittance of incident light is disposed opposite the display surface of the display. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention provides a display device that can selectively function as a mirror, the display device including: a display that emits image light; an optical device that can control the reflectance / transmittance of incident light, the optical device being arranged on the first direction side of the display so as to overlap with the display surface of the display when viewed in the first direction, the emission direction of the image light from the display being a first direction; and an anti-glare layer that performs at least one of scattering and diffusing the incident light, the anti-glare layer being arranged between the display and the optical device in the first direction so as to overlap with the display surface of the display when viewed in the first direction. Here, the display emits linearly polarized light in a predetermined direction as the image light, and the optical device includes a reflective polarizer whose polarization transmission axis is in the predetermined direction, a liquid crystal panel that is arranged on the first direction side of the reflective polarizer and can change the direction of the vibration plane of the incident linearly polarized light and emit it, and a polarizer that is arranged on the first direction side of the liquid crystal panel and whose polarization transmission axis is in the predetermined direction.

[0011] Here, in this display device, the display is, for example, a liquid crystal display. In the above display device, the haze value of the antiglare layer is preferably 30% or more. Furthermore, these display devices may be disposed above the front windshield of the vehicle so as to emit image light toward the rear of the vehicle. Alternatively, these display devices may be disposed on the sides of the front doors of the vehicle so as to emit image light toward the rear of the vehicle. In addition, a display system with anti-glare function may be configured by a display device mounted on such an automobile, a light detection means for detecting the intensity of light arriving from the rear of the automobile, and an anti-glare control means for controlling the reflectance / transmittance of the optical device according to the intensity of light detected by the light detection means so that the stronger the light intensity, the smaller the reflectance and the larger the transmittance.

[0012] According to a display device or display system having a structure in which an anti-glare layer is disposed between an optical device and a display as described above, the scattering or diffusing action of the anti-glare layer and the reflective action of the reflective polarizing plate of the optical device suppress the occurrence of defects such as the appearance of rainbow-colored images due to interference of light reflected from the display and cloudiness around bright reflected images. Effect of the Invention

[0013] As described above, according to the present invention, a display device in which an optical device capable of controlling the reflectance / transmittance of incident light is arranged opposite the display surface of the display can provide good, problem-free anti-glare performance. [Brief description of the drawings]

[0014] [Figure 1] 1 is a block diagram showing a configuration of a display system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing an arrangement of a display device according to an embodiment of the present invention. [Diagram 3] 1 is a diagram illustrating a schematic configuration of a display device according to an embodiment of the present invention. [Figure 4] 5A to 5C are diagrams illustrating a basic operation of the display device according to the embodiment of the present invention. [Diagram 5] FIG. 1 is a diagram showing the effect of an AG layer according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described. FIG. 1 shows the configuration of a display system according to this embodiment. The display system is a system installed in an automobile, and as shown in the figure, comprises a display device 1, a mode control device 2, a display control device 3, one or more video source devices 4, a control device 5, multiple sensors 6, and an input device 7.

[0016] The display device 1 is a device that can selectively function as a mirror or as a device that displays images, and is equipped with a liquid crystal display 11 that displays images, and an optical device 12 that is positioned at a position through which the image light emitted by the liquid crystal display 11 passes and is capable of controlling the reflectance / transmittance of incident light.

[0017] The display device 1 is disposed at a position where a rear-view mirror has traditionally been provided above the front windshield of an automobile, for example, as shown in Fig. 2. In a display mode in which the display device 1 functions as a device for displaying images, the display device 1 can be used as a display for displaying various information, and in a mirror mode in which the display device 1 functions as a mirror, the display device 1 can be used as a rear-view mirror.

[0018] However, the display device 1 may be disposed at the side of the front door of the automobile where a side mirror has traditionally been provided. In this case, in the display mode, the display device 1 can be used as a display that displays various information, and in the mirror mode, the display device 1 can be used as a side mirror.

[0019] Returning to Figure 1, video source device 4 is a device that outputs images such as a backup camera that captures the image behind the automobile, and display control device 3 controls the display of the images output by video source device 4 on liquid crystal display 11 in accordance with the control of control device 5.

[0020] Moreover, the mode control device 2 adjusts the reflectance / transmittance of the optical device 12 according to the control of the control device 5 . The multiple sensors 6 include an illuminance sensor for detecting the brightness of the surroundings, a light sensor for detecting the intensity of light coming from the rear of the automobile, and other sensors 6. The control device 5 performs a process of switching the video source device 4 that is the output source of the video to be displayed on the liquid crystal display 11 by the display control device 3 in accordance with a user operation or the like received by the input device 7 . Furthermore, the control device 5 switches the display device 1 between the display mode and the mirror mode in accordance with user operations received by the input device 7. Furthermore, during a period in which the detection value of the illuminance sensor detects that the surroundings are dark, the control device 5 sets the anti-glare level according to the intensity of light arriving from behind detected by the light sensor so that the greater the intensity of the light, the higher the anti-glare level becomes. Note that, during a period in which the detection value of the illuminance sensor detects that the surroundings are not dark, the anti-glare level is set to the minimum level at which anti-glare is not performed.

[0021] However, the brightness of the surroundings and the intensity of light coming from behind may be identified in the control device 5 from the image output by a backup camera provided as the image source device 4. When in the display mode, the control device 5 causes the mode control device 2 to adjust the reflectance / transmittance of the optical device 12 to low reflectance / high transmittance so that the display device 1 functions as a device for displaying images.

[0022] Furthermore, when in the mirror mode, the control device 5 causes the display control device 3 to turn off the display, and causes the mode control device 2 to adjust the reflectance / transmittance of the optical device 12 so that the display device 1 functions as a mirror and the higher the anti-glare level, the smaller the reflectance and the larger the transmittance. More specifically, during the mirror mode period, when the anti-glare level is at the lowest level, the mode control device 2 causes the mode control device 2 to adjust the reflectance / transmittance of the optical device 12 to a high reflectance / low transmittance, and causes the mode control device 2 to control the reflectance / transmittance of the optical device 12 so that the higher the anti-glare level, the smaller the reflectance and the larger the transmittance. Here, the smaller the reflectance and the larger the transmittance of the optical device 12, the stronger the degree of anti-glare of the display device 1 in the mirror mode.

[0023] Therefore, during the mirror mode, the stronger the light coming from behind, the stronger the degree of anti-glare of the optical device 12 becomes. Next, the configuration of the display device 1 is shown in FIG. As shown in the figure, the display device 1 has a structure in which a backlight 13 that emits illumination light for display, an air gap or OCA (Optical Clear Adhesive) 14, a backlight polarizer 111, a display LCD panel 112, a polarizer 113 for image light, an AG layer 15 (anti-glare layer), a reflective polarizer 121, a mode switching LCD panel 122, an external light polarizer 123, an air gap or OCA 16, and a cover glass 17 are layered from the back side of the display device 1.

[0024] The backlight polarizing plate 111, the display liquid crystal panel 112, and the image light polarizing plate 113 constitute the liquid crystal display 11. In the liquid crystal display 11, the direction of the polarization transmission axis of the image light polarizer 113 is set as a first direction, and the direction of the polarization transmission axis of the backlight polarizer 111 is set as a second direction that is perpendicular to the first direction. Only the linearly polarized component of the display illumination light emitted from the backlight 13 in the second direction passes through the backlight polarizer 111 and enters the display liquid crystal panel 112. In the display liquid crystal panel 112, the vibration plane of the display illumination light is adjusted to a desired direction for each pixel, and then colored and emitted to the image light polarizer 113. The image light polarizer 113 transmits only the linearly polarized component of the display illumination light incident from the display liquid crystal panel 112 in the first direction, and emits it as image light representing an image.

[0025] In addition, the display liquid crystal panel 112 has a structure in which, from the back side of the display device 1, a back transparent substrate 1121, a pixel electrode 1122, a back alignment film 1123, a liquid crystal layer 1124, a front alignment film 1125, a counter electrode 1126, a color filter and black matrix 1127, and a front transparent substrate 1128 are stacked.

[0026] By controlling the effective voltage applied to the liquid crystal layer 1124 by the pixel electrode 1122 and the counter electrode 1126 for each pixel, the orientation of the liquid crystal can be controlled for each pixel, and the vibration plane of the display illumination light emitted from the liquid crystal layer 1124 can be adjusted to a desired direction. Here, the display illumination light emitted from the liquid crystal layer 1124 is colored for each pixel by the color filter 1127 and emitted to the image light polarizing plate 113, and the component transmitted through the image light polarizing plate 113 becomes the image light.

[0027] Next, in such a display device 1, the optical device 12 is composed of a reflective polarizer 121, a mode switching liquid crystal panel 122, and an external light polarizer 123. The polarization transmission axes of the external light polarizer 123 and the reflective polarizer 121 are set in a first direction, which is the same as the polarization transmission axis of the image light polarizer 113 of the liquid crystal display 11. The reflective polarizer 121 is an optical device that transmits linearly polarized light in the direction of the polarization transmission axis and reflects linearly polarized light in a direction perpendicular to the polarization transmission axis, and since the polarization transmission axis is the first direction in this example, it transmits linearly polarized light in the first direction and reflects linearly polarized light in a second direction that is perpendicular to the first direction.

[0028] The mode-switching liquid crystal panel 122 can control the orientation of the liquid crystal within the mode-switching liquid crystal panel 122 to adjust the vibration plane of linearly polarized light incident on the mode-switching liquid crystal panel 122 to a desired direction before outputting it.

[0029] Next, the basic operations of such a display device 1 in the display mode and the mirror mode will be described. First, FIG. 4a shows a basic operation in the display mode, omitting the cover glass 17, the air gap, and the OCA, which are not involved in the operation. In the display mode, the mode-switching liquid crystal panel 122 is controlled by the mode control device 2 so as to emit the incident linearly polarized light while maintaining the vibration plane thereof as it is. The linearly polarized component of external light incident on external light polarizer 123 in the first direction passes through external light polarizer 123 with a polarization transmission axis in the first direction, and passes through mode switching liquid crystal panel 122 while maintaining the direction of the vibration plane in the first direction. The linearly polarized light in the first direction that passes through mode switching liquid crystal panel 122 passes through reflective polarizer 121 with a polarization transmission axis in the first direction, passes through AG layer 15, and enters liquid crystal display 11, whereupon most of it is absorbed.

[0030] On the other hand, as described above, image light including only linearly polarized light in the first direction is emitted from the liquid crystal display 11. The image light emitted from the liquid crystal display 11 passes through the AG layer 15 and the reflective polarizer 121 whose polarization transmission axis is in the first direction, and enters the mode switching liquid crystal panel 122. The image light that enters the mode switching liquid crystal panel 122 passes through the mode switching liquid crystal panel 122 while maintaining the direction of the vibration plane in the first direction, and also passes through the external light polarizer 123 whose polarization transmission axis is in the first direction, and is emitted to the outside. Then, the image is displayed by this image light emitted to the outside.

[0031] Next, FIGS. 4b1 and 4b2 show the basic operation in the mirror mode, omitting the cover glass 17, the air gap, and the OCA, which are not involved in the operation. FIG. 4b1 shows the basic operation when the anti-glare level is at the lowest level in the mirror mode, that is, when anti-glare is not performed. In the mirror mode, the liquid crystal display 11 is controlled by the display control device 3 so as not to emit image light by turning off the backlight 13 or displaying a black screen. Also, in the mirror mode, when the anti-glare level is at the lowest level, the mode switching liquid crystal panel 122 is controlled by the mode control device 2 so as to rotate the vibration plane of the linearly polarized light incident thereon by 90 degrees.

[0032] The linearly polarized light component in the first direction of the external light incident on the external light polarizer 123 is transmitted through the external light polarizer 123 with a polarization transmission axis in the first direction, and the direction of the vibration plane is rotated by 90 degrees by the mode switching liquid crystal panel 122, and the component is incident on the reflective polarizer 121 as linearly polarized light in the second direction. The reflective polarizer 121 reflects all of the external light incident from the mode switching liquid crystal panel 122, since the external light is linearly polarized light in the second direction perpendicular to the polarization transmission axis in the first direction. The reflected light of linearly polarized light in the second direction reflected by the reflective polarizer 121 is incident on the mode switching liquid crystal panel 122, and the vibration plane is rotated by 90 degrees by the mode switching liquid crystal panel 122, and the reflected light is output to the external light polarizer 123 as linearly polarized light in the first direction, and the reflected light is output to the outside as it is through the external light polarizer 123 with a polarization transmission axis in the first direction. The reflected light output to the outside also functions as a mirror of the display device 1.

[0033] Incidentally, even if liquid crystal display 11 is used for display when the anti-glare level is at the lowest level in mirror mode, image light that is linearly polarized in the first direction emitted from liquid crystal display 11 passes through AG layer 15 and reflective polarizer 121, has its vibration plane rotated by 90 degrees in mode switching liquid crystal panel 122, and enters external light polarizer 123 as linearly polarized light in the second direction, and is blocked by external light polarizer 123, so that the image on liquid crystal display 11 is not displayed and output to the outside. Therefore, when the anti-glare level is at the lowest level in mirror mode, it is acceptable to control liquid crystal display 11 to emit image light.

[0034] Next, FIG. 4b2 shows the basic operation when the anti-glare level is not the lowest level in the mirror mode, that is, when anti-glare is performed. As described above, in the mirror mode, the liquid crystal display 11 is controlled by the display control device 3 so as not to emit image light by turning off the backlight 13 or displaying a black screen. Also, in the mirror mode, when the anti-glare level is not the lowest level, the mode-switching liquid crystal panel 122 is controlled by the mode control device 2 so as to rotate the vibration plane of the incident linearly polarized light by an angle θ determined according to the anti-glare level within the range of 0<θ<90. The smaller the angle by which the vibration plane is rotated in the mode-switching liquid crystal panel 122, the smaller the reflectance and the higher the transmittance of the optical device 12. Therefore, the higher the anti-glare level, the smaller the angle by which the vibration plane is rotated in the mode-switching liquid crystal panel 122.

[0035] Then, the component of the external light that is linearly polarized in the first direction and incident on the external light polarizer 123 passes through the external light polarizer 123, whose polarization transmission axis is in the first direction, and the direction of the vibration plane is rotated by θ in the mode switching liquid crystal panel 122, so that the component is linearly polarized in a direction between the first and second directions and incident on the reflective polarizer 121.

[0036] The reflective polarizer 121 reflects the component of external light that is linearly polarized in the second direction and incident from the mode switching liquid crystal panel 122, and transmits the component of external light that is linearly polarized in the first direction. Therefore, the reflective polarizer 121 reflects a part of the external light that is incident from the mode switching liquid crystal panel 122 and transmits a part of it.

[0037] The reflected light of linear polarization in the second direction reflected by the reflective polarizer 121 enters the mode switching liquid crystal panel 122, where the vibration plane is rotated by θ and output to the external light polarizer 123, which outputs to the outside the display device 1 the linear polarization component in the first direction of the reflected light incident from the mode switching liquid crystal panel 122. This reflected light output to the outside realizes the mirror function of the display device 1, and the intensity of the reflected light output to the outside, i.e., the reflectance of the optical device 12, can be made smaller than when the anti-glare level is at the lowest level, thereby realizing anti-glare according to the anti-glare level.

[0038] On the other hand, external light that is linearly polarized in the first direction and that has been transmitted through the reflective polarizer 121 passes through the AG layer 15 and enters the liquid crystal display 11, whereupon most of the light is absorbed. Now, as shown in Figure 4b2, when the LCD display 11 is operated in a state in which the mode switching LCD panel 122 rotates the vibration plane of the incident linearly polarized light by an angle θ, the linearly polarized image light in the first direction emitted from the LCD display 11 passes through the AG layer 15 and the reflective polarizer 121, has its vibration plane rotated by θ in the mode switching LCD panel 122, and enters the external light polarizer 123, which then emits the linearly polarized component in the first direction of the image light incident from the mode switching LCD panel 122 to the outside.

[0039] Therefore, in this case, the image reflected by the reflective polarizing plate 121 and the image displayed on the liquid crystal display 11 are visually recognized as being superimposed on each other by the user. Therefore, the display system may further be provided with a synthesis mode, in which the mode switching liquid crystal panel 122 is controlled to rotate the vibration plane of the incident linearly polarized light by an angle θ, and the liquid crystal display 11 is caused to display an icon or the like, thereby allowing such a reflected image to be superimposed on the displayed image. Note that, even in the synthesis mode, the higher the anti-glare level, the smaller the angle by which the vibration plane is rotated in the mode switching liquid crystal panel 122, thereby improving anti-glare performance.

[0040] Next, the effect of providing the AG layer 15 of the display device 1 between the liquid crystal display 11 and the reflective polarizer 121 in this embodiment will be described. As shown in Fig. 5a1, if the AG layer 15 is not provided on the display device 1, when anti-glare is performed in mirror mode, external light reaches the liquid crystal display 11 as shown in Fig. 4b2, is diffracted and reflected by the color filter 1127 shown in Fig. 3, and interference light between the reflected lights is emitted from the front of the display device 1. This interference light causes a rainbow-colored image that does not actually exist behind the car to appear around the bright reflected image.

[0041] On the other hand, in the display device 1 of this embodiment in which an AG layer 15 is provided between the liquid crystal display 11 and the reflective polarizer 121, as shown in Figure 5a2, the light reflected by the color filter 1127 of the liquid crystal display 11 loses its phase alignment due to scattering in the AG layer 15, thereby reducing the degree of interference and preventing the appearance of a rainbow-colored image due to interference light.

[0042] Next, as shown in Figure 5b1, when an AG layer 15 is provided on the surface of the display device 1 on which external light is incident, in the mirror mode with a low anti-glare level, i.e., in a state in which the reflectance / transmittance of the optical device 12 is high reflectance / low transmittance, the external light and the reflected light of the external light are scattered and diffused by the AG layer 15, causing the area around a bright reflected image to appear cloudy.

[0043] On the other hand, as shown in Fig. 5b2, in the display device 1 of this embodiment, the external light scattered or diffused by the AG layer 15 provided between the liquid crystal display 11 and the reflective polarizer 121 and the reflected light of the external light do not have polarization properties, so the components heading toward the outside are mostly reflected by the reflective polarizer 121. Therefore, these lights are not emitted to the outside, and the area around the bright reflected image does not appear cloudy.

[0044] The AG layer 15 also acts on the image light emitted from the liquid crystal display 11, but like the case where the AG layer 15 is provided on the display surface of the liquid crystal display 11, the effect on the image light is small.

[0045] In order to fully obtain the above-mentioned effects of the AG layer 15, the haze value (Haze) of the AG layer 15 is set to 30% or more, preferably 40% or more. According to experiments conducted by the present inventors, if the haze value is less than 30%, it is not possible to suppress the appearance of strong rainbow-like images, if it is 30% or more, it is possible to suppress the appearance of rainbow-like images to a degree that does not cause practical problems, and if it is 40% or more, it is possible to effectively suppress the appearance of rainbow-like images. The upper limit of the haze value may be determined according to the application and the required image quality.

[0046] The embodiment of the present invention has been described above. Here, in the above description, the display device is provided with the liquid crystal display 11. However, a display other than a liquid crystal display may be used in place of the liquid crystal display 11 as long as it emits linearly polarized image light. [Explanation of symbols]

[0047] 1...display device, 2...mode control device, 3...display control device, 4...image source device, 5...control device, 6...sensor, 7...input device, 11...liquid crystal display, 12...optical device, 13...backlight, 14...air gap or OCA, 15...AG layer, 16...air gap or OCA, 17...cover glass, 111...backlight polarizer, 112...display liquid crystal panel, 113...image light polarizer, 121...reflective polarizer, 122...mode switching liquid crystal panel, 123...external light polarizer, 1121...rear transparent substrate, 1122...pixel electrode, 1123...rear alignment film, 1124...liquid crystal layer, 1125...front alignment film, 1126...counter electrode, 1127...color filter and black matrix, 1128...front transparent substrate.

Claims

1. A display device that can be selectively made to function as a mirror, comprising: A display that emits image light; an optical device capable of controlling a ratio of reflectance and transmittance of incident light, the optical device being disposed on a side of the display in a first direction such that the optical device overlaps with a display surface of the display when viewed in the first direction, the optical device defining an emission direction of image light from the display being a first direction; an antiglare layer that is provided between the display and the optical device in the first direction so as to overlap a display surface of the display when viewed in the first direction, and that performs at least one of scattering and diffusing incident light; the display emits linearly polarized light in a predetermined direction as the image light, the optical device includes a reflective polarizer having a polarization transmission axis in the predetermined direction, a liquid crystal panel arranged on the first direction side of the reflective polarizer and capable of changing the direction of a vibration plane of incident linearly polarized light and outputting the light, and a polarizer arranged on the first direction side of the liquid crystal panel and having a polarization transmission axis in the predetermined direction, A display device, wherein the haze value of the antiglare layer is 30% or more.

2. 2. The display device according to claim 1, wherein the display is a liquid crystal display.

3. A display device according to claim 1 or 2, The display device is disposed above the front windshield of the vehicle so as to emit image light toward the rear of the vehicle.

4. A display device according to claim 1 or 2, The display device is disposed on the side of a front door of the vehicle so as to emit image light toward the rear of the vehicle.

5. A display device according to claim 3 or 4, a light detection means for detecting the intensity of light coming from the rear of the vehicle; and an anti-glare control means for controlling the ratio of reflectance to transmittance of the optical device in accordance with the intensity of light detected by the light detection means so that the stronger the intensity of light, the smaller the reflectance and the larger the transmittance.

Images