Light control device

Abstract

This light control device (10) for a vehicle adjusts the amount of incident light into a cabin (1a) and comprises: a windshield (11) for a vehicle, the windshield (11) being configured so as to include a light control material in which the visible light transmittance decreases in response to ultraviolet light and the visible light transmittance increases in response to at least one of visible light or heat; and a light irradiation unit (30) that irradiates the windshield with ultraviolet light from the inside of the cabin (1a). The light control material included in an upper region (111), which is the upper side of two regions obtained by vertically dividing the windshield (11) into two, has a slower rate of increase in visible light transmittance than the light control material included in a non-upper region (112), which is the lower side of the regions.

Description

dimmer

[0001] The present disclosure relates to a light control device.

[0002] 2. Description of the Related Art Conventionally, there has been known an anti-glare device that uses a member capable of changing the transmittance of visible light in a vehicle windshield.

[0003] For example, Patent Document 1 describes a technology in which a windshield containing a photochromic material that changes color with ultraviolet light is irradiated with ultraviolet light to change the color and reduce the transmittance of external light. In this technology, the windshield instantly loses its color when the ultraviolet light irradiation is stopped in order to ensure visibility while driving.

[0004] Patent No. 6392651

[0005] In the technology of Patent Document 1, the windshield instantly loses color and its external light (visible light) transmittance increases when UV irradiation is stopped. Therefore, if the windshield's visible light transmittance is maintained at a reduced level, the amount of UV irradiation increases, and more energy is required to cool the UV light source. Furthermore, the increased amount of UV irradiation may accelerate deterioration of the windshield.

[0006] The present disclosure aims to provide anti-glare protection while ensuring the driver's field of vision, reduce the amount of ultraviolet radiation to contribute to energy savings, and suppress deterioration of the windshield.

[0007] One aspect of the present disclosure is a light control device for a vehicle that adjusts the amount of light incident on a vehicle interior, the light control device comprising: a vehicle windshield containing a light control material that reacts to ultraviolet rays to decrease its visible light transmittance and reacts to at least one of visible light and heat to increase its visible light transmittance; and a light irradiation unit that irradiates ultraviolet rays onto the windshield from inside the vehicle interior, wherein the light control material contained in a first region, which is the upper of two regions obtained by dividing the windshield into upper and lower halves, has a slower rate of increase in visible light transmittance than the light control material contained in a second region, which is the lower of the two regions.

[0008] According to the present disclosure, it is possible to provide glare protection while ensuring the visibility of the vehicle driver, and further to reduce the amount of ultraviolet radiation, thereby contributing to energy savings, and to suppress deterioration of the windshield.

[0009] 1 is a block diagram showing an example of a schematic configuration of a light control device of an embodiment; FIG. 2 is a diagram showing an example of the arrangement of each component of the light control device of the first embodiment; FIG. 3 is a cross-sectional view and a front view showing an example of the schematic configuration of a windshield in the light control device of the first embodiment; FIG. 4 is a cross-sectional view showing another example of the schematic configuration of the windshield in the light control device of the first embodiment; FIG. 5 is a diagram showing an example of an irradiation mode of ultraviolet light in the light control device of the first embodiment; FIG. 6 is a diagram showing another example of an irradiation mode of ultraviolet light in the light control device of the first embodiment; FIG. 7 is a diagram explaining an example of the coloring behavior of a photochromic material; FIG. 8 is a diagram explaining an example of the decolorization behavior of a photochromic material; FIG. 9 is a diagram showing an example of the configuration of a light irradiation unit in the light control device of the first embodiment; FIG. 10 is a diagram showing another example of the configuration of a light irradiation unit in the light control device of the first embodiment;

[0010] (First embodiment) (Configuration) A light control device according to an embodiment of the present disclosure will be described below with reference to the drawings. The following drawings are schematic diagrams, and the size and shape of each part are appropriately exaggerated or simplified to facilitate understanding. First, the configuration of a light control device according to an embodiment will be described with reference to FIGS. 1A and 1B. A light control device 10 provided in a vehicle 1 has a light control function for adjusting the intensity (amount of light) of external light (visible light) such as sunlight entering a vehicle interior 1a from the outside. As shown in FIG. 1A, the light control device 10 includes a windshield 11, a light irradiation unit 30, an external illuminance measurement unit 60, a control unit 70, and a memory unit 80.

[0011] The windshield 11 is a front windshield for a vehicle that is disposed in a planar form at the front of the vehicle 1, i.e., in front of the driver, and is configured to include a light control member 20 that can change light transmittance. The windshield 11 has a multi-layer structure, and the light control member 20 is one of the multi-layer structure.

[0012] The light control member 20 is a sheet-like or plate-like member that is provided on the windshield 11. The light control member 20 is formed by containing a light control material, and the light control material acts to change the visible light transmittance of the windshield 11, thereby providing anti-glare to light entering the vehicle interior 1a from the windshield 11.

[0013] The light-adjusting component 20, which contains a light-adjusting material, has optical properties that allow it to color in response to ultraviolet light and to lose its color in response to at least one of visible light and heat. When the light-adjusting material in the light-adjusting component 20 is colored, its visible light transmittance (hereinafter also referred to simply as "light transmittance") decreases, and when it is decolored, the light transmittance increases (restores). Therefore, the light-adjusting component 20 has a photoresponsive property in which its light transmittance decreases upon receiving ultraviolet light (ultraviolet light) and increases upon receiving at least one of visible light and heat. For example, the light-adjusting component 20 becomes colored (light transmittance decreases) upon irradiation with ultraviolet light, and loses its color (light transmittance increases) upon cessation of ultraviolet irradiation due to at least one of sunlight and temperature. Note that decolorization may be affected not only by the outside temperature but also by the temperature inside the vehicle interior 1a.

[0014] In this way, the windshield 11 contains a photochromic material whose light transmittance decreases in response to ultraviolet light and whose light transmittance increases in response to at least one of visible light and heat. As will be described in detail later, the photochromic member 20 is formed by containing, for example, a photochromic compound (photochromic material) as the photochromic material.

[0015] The light-adjusting component 20 has a normal anti-glare region 21 (an example of a first region) that contributes to normal anti-glare, and a temporary anti-glare region 22 (an example of a second region) that contributes to temporary (as-needed) anti-glare. The normal anti-glare is, for example, anti-glare against normal sunlight during the day, while the temporary anti-glare is, for example, anti-glare against very strong sunlight or against light sources other than sunlight (for example, headlights of oncoming vehicles).

[0016] The normal antiglare region 21 is a region that can be continuously colored (with reduced light transmittance) while the vehicle 1 is in operation, and the temporary antiglare region 22 is a region that can be temporarily colored (as needed) while the vehicle 1 is in operation. In this embodiment, the photochromic material contained in the normal antiglare region 21 and the photochromic material contained in the temporary antiglare region 22 have different decolorization rates, i.e., different rates at which light transmittance increases after UV irradiation is stopped. Details of the photochromic material will be described later.

[0017] The normal anti-glare area 21 is the upper of the two areas (closer to the ceiling 2) that divide the windshield 11 into upper and lower halves, and the temporary anti-glare area 22 is the lower of the two areas (closer to the dashboard 4), i.e., the area other than the normal anti-glare area 21. The normal anti-glare area 21 corresponds to the upper area 111 of the windshield 11, and the temporary anti-glare area 22 corresponds to the non-upper area 112 of the windshield 11. Therefore, the normal anti-glare area 21 is colored by ultraviolet light irradiated onto the upper area 111, and the temporary anti-glare area 22 is colored by ultraviolet light irradiated onto the non-upper area 112.

[0018] The light irradiation unit 30 irradiates ultraviolet (UV) rays from the interior of the vehicle (inside the passenger compartment 1a) onto the windshield 11 equipped with the light-adjusting member 20. The ultraviolet rays from the light irradiation unit 30 cause the windshield 11 (light-adjusting member 20) to become colored, reducing light transmittance and adjusting the light intensity within the passenger compartment 1a. The light irradiation unit 30 is a UV irradiation device, and is installed, for example, in a position (e.g., on the ceiling 2) where the direction of irradiation of the ultraviolet light onto the windshield 11 is below horizontal, as shown in FIG. 2 . The light irradiation unit 30 is installed, for example, directly on the ceiling 2 or indirectly via a predetermined member. The light irradiation unit 30 is preferably installed, for example, above the driver (e.g., the driver's seat 3). The light irradiation unit 30 also includes an ultraviolet (UV) light source unit 31 and a drive unit 32.

[0019] The UV light source unit 31 is a light source that irradiates light onto the windshield 11 and includes one or more light-emitting elements. Examples of light-emitting elements include, but are not limited to, ultraviolet light-emitting diodes (UV-LEDs) and ultraviolet laser diodes (UV-LDs). The UV light source unit 31 is connected to a rotating member (not shown) and is rotatable in the vertical and horizontal directions. The drive unit 32 includes a light source drive circuit that supplies a drive signal related to the ultraviolet light irradiation mode to the UV light source unit 31. The drive unit 32 also includes an actuator drive circuit that supplies a drive signal related to the rotation angle to the actuator of the rotating member. The drive unit 32 generates a drive signal in response to a control signal from the control unit 70 and supplies the drive signal to the UV light source unit 31 and the rotating member.

[0020] That is, the light irradiation unit 30 changes whether or not the UV light source unit 31 emits (irradiates) ultraviolet light, and the irradiation mode of the ultraviolet light (illuminance, number of irradiations, etc.), based on a drive signal corresponding to a control signal from the control unit 70. The light irradiation unit 30 also drives the actuator of the rotating member based on a drive signal supplied from the drive unit 32, causing the UV light source unit 31 to rotate. That is, the light irradiation unit 30 changes the irradiation angle of the ultraviolet light emitted by the UV light source unit 31, i.e., the irradiation range. As a result, the light irradiation unit 30 irradiates not only the upper region 111 but also the non-upper region 112 of the windshield 11 with ultraviolet light, and can color the temporary anti-glare region 22 as needed in addition to the normal anti-glare region 21.

[0021] The rotating member that changes the irradiation direction of the ultraviolet light may be, for example, a member that rotates the light irradiation unit 30 (UV irradiation device) itself, thereby enabling the irradiation range to be changed in even more diverse ways.

[0022] The external illuminance measuring unit 60 is equipped with an illuminance meter and measures the brightness (illuminance) outside the vehicle (outdoors). The external illuminance measuring unit 60 is installed, for example, at the lower part of the windshield 11 on the passenger compartment 1a side (for example, on the instrument panel). The external illuminance measuring unit 60 may be installed at any position on the exterior side of the vehicle 1, or may also serve as an illuminance meter for controlling the illumination of headlights (auto lights). The external illuminance measuring unit 60 transmits a signal (illuminance signal) indicating the external illuminance of the vehicle 1 to the control unit 70.

[0023] The control unit 70 includes one or more processors and memory (RAM and ROM) that stores programs executable by the processors. The control unit 70 is, for example, a microcomputer that reads the programs from the memory using the processor and executes processing in accordance with the programs, thereby realizing control and various functions of the light control device 10. The microcomputer functions as multiple information processing circuits (data acquisition unit 71, irradiation control unit 72) in the light control device 10. Note that the information circuits may be realized by software, or may be configured by one or more pieces of hardware for executing each information processing. Furthermore, the control unit 70 is not limited to a microcomputer, and a single-board computer or the like may also be used.

[0024] The control unit 70 is connected to each part of the light control device 10 and various sensors and switches of the vehicle 1 so as to be able to communicate information with each part, and can control each part of the light control device based on the state of the vehicle 1. The control unit 70 is installed, for example, in the dashboard 4 of the vehicle, but is not limited to this and may be installed, for example, in the light irradiation unit 30 (ultraviolet irradiation device).

[0025] The control unit 70 controls the light intensity and illumination of the vehicle interior 1a by controlling the change in the light transmittance of the windshield 11. For example, the control unit 70 reads the illumination mode, including the illuminance and number of irradiations of ultraviolet light, from the memory unit 80 and controls the illumination of ultraviolet light by the light illumination unit 30 based on the illumination and number of irradiations indicated by the illumination mode. The number of irradiations indicates the length of the ultraviolet illumination time. In other words, controlling the number of irradiations corresponds to controlling the ultraviolet illumination time. Note that the illumination time per ultraviolet illumination may be a fixed value, or the illumination mode may include the illumination time per illumination. The control unit 70 supplies control signals indicating the illumination mode and the illumination range to the drive unit 32 of the light illumination unit 30. As a result, the light illumination unit 30 irradiates the illumination range indicated by the control signal with ultraviolet light according to the illumination mode indicated by the control signal. The control unit 70 may also supply a control signal to the drive unit 32 of the light illumination unit 30 to control whether or not the UV light source unit 31 emits ultraviolet light.

[0026] The storage unit 80 stores various data that the control unit 70 uses to control each component of the light control device 10. For example, the storage unit 80 stores dimming data that is used for dimming control by the control unit 70. The storage unit 80 stores, as the dimming data, a plurality of irradiation modes that include at least the illuminance and number of irradiations of ultraviolet light. The dimming data stored in the storage unit 80 is data that associates each irradiation mode with illuminance data that indicates the illuminance (brightness) outdoors of the vehicle 1. In other words, the storage unit 80 stores a plurality of pieces of dimming data 81 that are configured by combining illuminance data and irradiation modes.

[0027] The illuminance data in the light adjustment data 81 is numerical data indicating the external illuminance (lx) expected for each environmental condition, such as the season, weather, time of day (e.g., morning, daytime, afternoon), etc. The illuminance data is also associated with a mode of ultraviolet irradiation for stably coloring the windshield 11 under the external illuminance environment indicated by the illuminance data. Note that the illuminance data in the light adjustment data 81 may be a fixed value, but it is preferable to set it to a numerical range taking into account the amount of data in the light adjustment data 81.

[0028] Next, we will explain the information processing circuit included in the control unit 70. The control unit 70 includes a data acquisition unit 71 and an irradiation control unit 72. The data acquisition unit 71 acquires data related to dimming control from each device that can communicate with the control unit, and outputs the data to the irradiation control unit 72. For example, the data acquisition unit 71 acquires an illuminance signal indicating external illuminance from the external illuminance measurement unit 60, and outputs the signal to the irradiation control unit 72.

[0029] The irradiation control unit 72 reads out the dimming data from the storage unit 80, and controls the irradiation of ultraviolet light by the light irradiation unit 30 based on the illuminance and number of irradiations indicated by the irradiation mode of the read dimming data 81. The irradiation control unit 72 reads out the irradiation mode of the dimming data 81 corresponding to the external illuminance from the storage unit 80 based on the illuminance signal output by the data acquisition unit 71. The irradiation control unit 72 identifies the illuminance data among the plurality of dimming data 81 that corresponds to the external illuminance indicated by the illuminance signal, and reads out the irradiation mode associated with the identified illuminance data from the storage unit 80.

[0030] The irradiation control unit 72 generates a control signal indicating the read irradiation mode (illuminance, number of irradiations) and supplies it to the light irradiation unit 30 (drive unit 32). As a result, under the control of the control unit 70, the light irradiation unit 30 irradiates the windshield 11 with ultraviolet light in an irradiation mode (illuminance, number of irradiations) corresponding to the current outdoor illuminance. In other words, by using the light adjustment data 81, the control unit 70 controls the ultraviolet light irradiation by the light irradiation unit 30 according to the outdoor illuminance, thereby minimizing the amount of ultraviolet light irradiation and contributing to energy conservation. In other words, the light adjustment device 10 can adjust the light transmittance of the windshield 11 according to various environmental conditions, thereby adjusting the light inside the vehicle interior 1a.

[0031] The irradiation control unit 72 can also control the irradiation range of the ultraviolet light irradiated by the light irradiating unit 30 (the colored area of ​​the windshield 11) according to the outdoor illuminance.

[0032] In principle, the control unit 70 determines the irradiation range of ultraviolet rays from the light irradiation unit 30 to be the upper region 111 of the windshield 11. Furthermore, in certain cases (for example, when the sun is low in the morning or evening and sunlight is directly incident on the faces of occupants through the non-upper region 112), the control unit 70 may determine the irradiation range of ultraviolet rays from the light irradiation unit 30 to be the upper region 111 and the non-upper region 112 of the windshield 11, i.e., the entire surface of the windshield 11 on the inside of the passenger compartment 1a (hereinafter referred to as "the entire surface of the windshield 11").

[0033] For example, the control unit 70 may control the illumination range based on outdoor illuminance, or may determine whether to include the temporary anti-glare area 22 in the illumination range based on the current light transmittance of the normal anti-glare area 21 (upper area 111) and the temporary anti-glare area 22 (non-upper area 112). When control is performed based on light transmittance, the light control device 10 may be provided with a visible light transmittance measuring device.

[0034] The irradiation control unit 72 generates a control signal indicating the determined irradiation range and supplies it to the drive unit 32 of the light irradiation unit 30. This controls the irradiation range of the ultraviolet light irradiated from the light irradiation unit 30 onto the windshield 11 depending on whether the vehicle 1 is in operation or not.

[0035] In this way, in the light control device 10, the windshield 11 contains a light-controlling material (e.g., a photochromic material), and the windshield 11 is colored and its light transmittance is appropriately adjusted by ultraviolet irradiation performed by the light irradiating unit 30 based on a control signal from the control unit 70. In other words, the light control device 10 adjusts the amount of external light entering the vehicle interior 1a by changing the light transmittance of the light control member 20, thereby controlling the light in the vehicle interior 1a.

[0036] Next, the configuration of the windshield 11 will be described in detail with reference to Figure 2A. As shown on the left side of Figure 2A, the windshield 11 has a multi-layer structure and includes a transparent substrate 12 made of glass, a light control member 20, and a specific light-blocking member 13. The transparent substrate 12 may be made of, for example, green-tinted green glass, and may have heat absorption and ultraviolet blocking properties. The light control member 20 and the specific light-blocking member 13 are disposed adjacent to each other between two opposing transparent substrates 12 and are provided as intermediate films sandwiched between the transparent substrates 12.

[0037] The specific light-blocking member 13 is positioned forward of the light-adjusting member 20, i.e., on the outdoor side. The specific light-blocking member 13 is a sheet-like member based on, for example, PVB (polyvinyl butyral) resin. It exhibits high adhesiveness and prevents the transparent substrate 12 from shattering even when the windshield 11 receives a strong impact. The specific light-blocking member 13 is also coated (or mixed) with an ultraviolet-blocking material that blocks at least ultraviolet light. This blocks ultraviolet light incident on the light-adjusting member 20 from outside the vehicle 1, preventing unintended coloring of the light-adjusting member 20 and reducing deterioration of interior components in the passenger compartment 1a and sunburn of occupants due to exposure to ultraviolet light. The specific light-blocking member 13 preferably blocks at least 99.9% of light in the ultraviolet wavelength range, for example.

[0038] The specific light-blocking member 13 is preferably configured to be able to block infrared rays in addition to ultraviolet rays. That is, it is preferable that an infrared-blocking material that blocks infrared rays is applied (or mixed) to the specific light-blocking member 13. This reduces the heat felt by occupants in the vehicle interior 1a due to exposure to infrared rays. The specific light-blocking member 13 preferably blocks, for example, 90% or more of light in the infrared wavelength range.

[0039] The light control member 20 is disposed rearward of the specific light blocking member 13, i.e., on the vehicle interior 1a side. The light control member 20 is made of a resin composition containing a photochromic compound. The light control member 20 is a sheet or plate-like member whose base material is, for example, a PVB resin blended with a photochromic compound. The sheet or plate-like member may be sandwiched between transparent substrates or attached to the vehicle interior side of the transparent substrate.

[0040] 2A, the surface area of ​​the light control member 20 is approximately the same as that of the rearmost transparent substrate 12 (on the vehicle interior 1a side), and is disposed in a planar form in front of the driver of the vehicle 1. Therefore, ultraviolet light emitted from the light irradiation unit 30 is irradiated onto the light control member 20 through the surface of the rearmost transparent substrate 12 (surface 11a of the windshield 11).

[0041] Furthermore, the area of ​​normal anti-glare region 21 in light control member 20 is smaller than that of temporary anti-glare region 22. Specifically, normal anti-glare region 21 is an area above the eye level of the driver of vehicle 1, and temporary anti-glare region 22 is an area outside normal anti-glare region 21 that includes the eye level of the driver (an area below normal anti-glare region 21). Therefore, the normal anti-glare region 21 can maintain a low visible light transmittance state (colored state) while maintaining good visibility for the driver, thereby reducing glare while driving.

[0042] Here, the allocation of the normal antiglare area 21 and the temporary antiglare area 22 will be described in more detail. As shown in the front view on the right side of Figure 2A, in this example, the normal antiglare area 21 (upper area 111) is separated from the temporary antiglare area 22 by an imaginary line L10 located above an imaginary line L1 passing through point P1, which indicates the reference position of the driver's line of sight. Point P1 is the point obtained by projecting point V1, which is the reference for test areas A and B defined in the appendix of JIS R3212 (1998), onto the windshield 11.

[0043] In the above annex, point V1 is defined as follows: - Point V1 with point R as the origin: The point 68 mm in the +X direction, 5 mm in the +Y direction, and 665 mm in the +Z direction from point R. - Point R (seating reference point): Point R is the position of point H (the hip joint point of the mannequin) when a mannequin defined in ISO 6549 (1980) is seated in a seat (the rearmost position for seats that can be adjusted forward and backward, the lowest position for seats that can be adjusted up and down, and the positions adjusted to the standard design angles for seats with adjustable seat back and seat cushion angles), or an equivalent standard design position. - X axis: The horizontal plane that passes through point R, and the axis that passes through point R and is parallel to the vehicle center line (longitudinal direction).

[0044] +X: rearward direction of the car, -X: forward direction of the car ・Y axis: horizontal plane passing through point R, axis perpendicular to the X axis. +Y: rightward direction of the car, -Y direction: leftward direction of the car ・Z axis: vertical plane passing through point R, axis perpendicular to the X and Y axes. +Z: upward direction of the car, -Z direction: downward direction of the car

[0045] - Vehicle center line: The following straight line when the vehicle is placed on a flat surface. (1) For vehicles with four or more wheels, the straight line passing through the center of the line segment connecting the design center points of the left and right front wheels and the rear wheels. (2) For vehicles with three wheels (one front wheel), the straight line passing through the midpoint of the line segment connecting the design center points of the left and right rear wheels and the design center point of the front wheel (this also applies to the single rear wheel). (3) For vehicles with tracks, the straight line equidistant from the center lines of the left and right tracks.

[0046] In this embodiment, the normal anti-glare area 21 is defined as the area above the imaginary line L1 passing through point P1, i.e., the area not including point P1. In other words, the normal anti-glare area 21 (upper area 111) of the windshield 11 is the area above the eye level of the driver of the vehicle 1. This allows for continuous anti-glare protection while maintaining good visibility for the driver while driving.

[0047] In this example, the region above imaginary line L10, which is parallel to imaginary line L1 and located above imaginary line L1, and does not include point P1, is the normal anti-glare region 21. As described above, by coloring the temporary anti-glare region 22 (non-upper region 112) including point P1 (the driver's line of sight) as needed, temporary anti-glare can be achieved when sunlight is very strong or against light sources other than sunlight, such as the headlights of oncoming vehicles. Furthermore, by designating the region above point P1 as the normal anti-glare region 21, it is possible to reliably protect against sunlight while ensuring the driver's field of vision, even in a vehicle in which the windshield 11 extends all the way to the ceiling 2.

[0048] Furthermore, for example, if the windshield 11 does not extend to the ceiling 2, the vertical width (height) of the normal anti-glare area 21 may be within 20% of the vertical width of the windshield 11. This minimizes the colored area of ​​the windshield 11 while the vehicle 1 is being driven, and reduces glare while ensuring the driver's visibility to the extent that the environment outside the vehicle can be seen.

[0049] Furthermore, the colored state of the normal antiglare region 21 and the temporary antiglare region 22 is preferably a state in which the light transmittance is 50% or less of that in the decolored (colorless) state, thereby reliably reducing the glare felt by the driver while driving the vehicle 1. The light transmittance in the colored state can be appropriately adjusted by the content of the photochromic compound and the thickness of the light control component 20.

[0050] Furthermore, with regard to the photochromic material (e.g., photochromic material) in the photochromic component 20 that changes color in response to ultraviolet light, it is preferable that the photochromic material constituting the normal antiglare region 21 (upper region 111) have a lower light transmittance when colored than the photochromic material constituting the temporary antiglare region 22 (non-upper region 112). This reduces the amount of sunlight incident on the upper region 111 of the windshield, where sunlight is likely to be incident around noon when anti-glare is required. Furthermore, the increase in light transmittance is appropriately suppressed in the non-upper region of the windshield 11, which includes point P1, which indicates the reference point for the driver's line of sight, ensuring visibility.

[0051] The light transmittance during coloring may be controlled, for example, by the concentration of the photochromic material in each region (normal antiglare region 21, temporary antiglare region 22) of the light-adjusting component 20, or the thickness of each region. For example, the concentration of the photochromic material in the normal antiglare region 21 may be controlled to be higher than the concentration of the photochromic material in the temporary antiglare region 22, or the thickness of the normal antiglare region 21 may be controlled to be thicker than the thickness of the temporary antiglare region 22. In a configuration in which the windshield 11 of the vehicle 1 extends to the ceiling 2, the entire region above point P1, which indicates the reference position of the driver's line of sight, is designated as the normal antiglare region 21, and the light-adjusting component 20 may be formed so that the light transmittance of the normal antiglare region 21 during coloring is lower than that of the temporary antiglare region 22.

[0052] Furthermore, temporary anti-glare area 22 in light-adjusting component 20 is an area including point P1, which indicates the reference line of sight of the driver, i.e., an area within the field of vision of the driver, and the light transmittance of temporary anti-glare area 22 when uncolored (completely decolorized) is required to be 70% or higher. This ensures that the field of vision necessary for the driver to check traffic conditions, etc. is secured.

[0053] As will be described in more detail later, in this embodiment, the normal antiglare region 21 (the upper region 111 of the windshield 11) of the light-adjusting component 20 contains a light-adjusting material (e.g., a photochromic compound) whose light transmittance increases (discolors) more slowly than the temporary antiglare region 22 (the non-upper region 112). This allows the normal antiglare region 21, which corresponds to the upper region 111, located above the driver's eye level and receiving a relatively large amount of sunlight, to maintain a reduced light transmittance (colored state) for a long period of time, even after UV irradiation has stopped, eliminating the need for frequent UV irradiation. Meanwhile, the temporary antiglare region 22, which corresponds to the non-upper region 112 including point P1, which indicates the reference point for the driver's eye level, quickly discolors, ensuring visibility. This provides glare protection while ensuring the driver's visibility, reduces UV irradiation, contributes to energy savings, and suppresses windshield deterioration.

[0054] The windshield 11 is not limited to the configuration illustrated in FIG. 2A . As shown in FIG. 2B , a specific light-blocking member 13 may be disposed in the position where the intermediate film of the windshield 11 would be disposed, and a light-adjusting member 20 may be disposed on the outermost surface of the windshield 11 facing the passenger compartment 1a. In this case, the light-adjusting member 20 is attached to the surface of the transparent substrate 12 facing the passenger compartment 1a. When installed in the passenger compartment 1a, the light-adjusting member 20 may be hard-coated to improve abrasion resistance and scratch resistance while maintaining its original properties. The configuration example of the windshield 11 shown in FIG. 2B allows for easier placement and replacement of the light-adjusting member 20 compared to the configuration example shown in FIG. 2A . Furthermore, for example, the light-adjusting device 10 may further include side windshields 110 (see FIG. 1B ) containing a photochromic compound and provided on the left and right sides of the windshield 11. In this case, the side windshields 110 may contain the same photochromic compound as the normal anti-glare region 21, contributing to continuous anti-glare protection while driving.

[0055] Next, the manner in which ultraviolet rays are irradiated onto the windshield 11 will be described. When the vehicle 1 is in a driving state, the light control device 10 according to this embodiment generally irradiates an upper region 111 of the surface 11a of the windshield 11 with ultraviolet rays from the light irradiator 30, and changes the irradiation range of ultraviolet rays from the light irradiator 30 to the entire surface 11a of the windshield 11 depending on the external light conditions (the intensity of sunlight, the presence of a light source other than sunlight), etc. In other words, the light irradiator 30 irradiates ultraviolet rays 31a onto the upper region 111 (normal anti-glare region 21) when the vehicle is in a driving state, as shown in Fig. 3A, and irradiates ultraviolet rays 31a onto the entire surface 11a of the windshield 11 (normal anti-glare region 21 and temporary anti-glare region 22) as needed, as shown in Fig. 3B.

[0056] 3A , when the vehicle 1 is in operation, only the normal antiglare region 21 is colored and the light transmittance of only the upper region 111 is reduced, thereby reducing glare while ensuring the driver's field of view. Furthermore, the illumination mode shown in FIG. 3B , both the normal antiglare region 21 and the temporary antiglare region 22 are colored, reducing the light transmittance of the entire windshield 11. Therefore, the windshield 11 suppresses external light from entering the vehicle interior 1a over a wide area, more reliably reducing glare for the driver. As described above, the illumination range is determined by the control unit 70 depending on the external light conditions, etc., and the movable member of the light irradiator 30 rotates under the control of the control unit 70 to irradiate the determined illumination range with ultraviolet light.

[0057] Whether the vehicle 1 is in a driving state can be determined based on the states of a main switch and a shift lever related to starting the engine of the vehicle 1. For example, the illumination control unit 72 can determine that the vehicle 1 is in a driving state when the conditions that the main switch is in an on state and the shift lever is in a range other than parking are satisfied. The states of the main switch and the shift lever may be acquired by, for example, the data acquisition unit 71 and output to the illumination control unit 72.

[0058] Next, we will explain the photochromic compound used in the light-adjusting member 20. A photochromic compound is a compound whose molecular structure changes under the action of light or heat, and which reversibly generates two isomers with different colors and absorption spectra.

[0059] In this embodiment, the normal antiglare region 21 (the upper region 111 of the windshield 11) of the light-adjusting component 20 contains a photochromic compound with a slower decolorization rate than the temporary antiglare region 22 (the non-upper region 112). Therefore, the light transmittance of the normal antiglare region 21 increases gradually after UV irradiation is stopped, and the colored state can be maintained for a predetermined period even after UV irradiation is stopped. This reduces the UV illuminance and number of irradiations required to maintain the colored state. Reducing the number of irradiations means reducing the irradiation time. In other words, reducing the illuminance and number of irradiations reduces the cumulative amount of UV light (= illuminance × irradiation time) required to maintain the colored state, contributing to energy conservation. Thus, using a photochromic material with a slower decolorization rate in the normal antiglare region 21 than in the temporary antiglare region 22 provides antiglare while maintaining the driver's field of vision, reduces the amount of UV irradiation, contributing to energy conservation, and suppresses windshield deterioration.

[0060] Furthermore, the temporary anti-glare region 22 contains a photochromic compound that fades faster than the normal anti-glare region 21, enabling the driver's field of vision to be quickly ensured while reducing glare. In this embodiment, for example, a light-returning (P-type) photochromic compound or a heat-returning (T-type) photochromic material is used for the light-adjusting component 20. Light-returning photochromic materials have high thermal stability, and their molecular structure changes reversibly only under the action of light. In other words, the light-adjusting device 10 can use a photochromic material that increases visible light transmittance (bleaches) in response to visible light as the light-adjusting material that constitutes the windshield 11.

[0061] In addition, the heat-reversible photochromic material stably loses its color when exposed to light or heat, restoring its light transmittance. In other words, the light-adjusting device 10 can use a photochromic material, whose visible light transmittance increases in response to heat, as the light-adjusting material that constitutes the windshield 11.

[0062] First, the light-returning photochromic material will be described. The light-returning photochromic compound used in the light-adjusting member 20 is not particularly limited, but for example, diarylethene-based and fulgide-based photochromic compounds can be used.

[0063] For example, as shown in the following reaction formula (1), when a diarylethene derivative is irradiated with ultraviolet light, it generates a closed-ring product, develops color, and changes its absorption spectrum. Specifically, along with the color development, an absorption band in the absorption spectrum appears in the visible light range. Furthermore, when a closed-ring diarylethene derivative is irradiated with visible light or infrared light, it returns to its original open-ring product, and as the color disappears, the absorption spectrum returns to its original state. In other words, the ultraviolet ring-opening reaction and the ring-closing reaction occur reversibly under the action of light, and the optical state changes between a colored state and a transparent state.

[0064]

[0065] As described above, the normal antiglare region 21 and the temporary antiglare region 22 contain different photochromic compounds.

[0066] For example, the temporary antiglare region 22 can use a diarylethene derivative (reaction formula (2) below) in which the substituent R in the reaction formula (1) is a cyano group.

[0067]

[0068] For example, the normal antiglare region 21 can use a diarylethene derivative (reaction formula (3) below) in which the substituent R in the reaction formula (1) is a methyl group.

[0069]

[0070] The diarylethene derivative of the above reaction formula (2) (hereinafter referred to as "diarylethene derivative A") has a faster decolorization rate than the diarylethene derivative of the above reaction formula (3) (hereinafter referred to as "diarylethene derivative B") Here, the decolorization rate is the speed at which the colored state changes to a transparent state when ultraviolet irradiation is stopped and visible light to infrared light (external light irradiation) is applied (the decolorization reaction rate).

[0071] For example, in an environment where visible light with a wavelength of 550 nm is irradiated as external light onto a windshield 11 in which the temporary antiglare region 22 contains diarylethene derivative A, the light transmittance when the ultraviolet irradiation is stopped is about 5%, at which point the degree of coloration of the temporary antiglare region 22 reaches its maximum (light transmittance is at its minimum). After the ultraviolet irradiation is stopped, the degree of coloration of the temporary antiglare region 22 gradually decreases (light transmittance gradually increases), and it takes about 2 seconds for the light transmittance to reach 50% (coloration gradual decrease time). Approximately 5 seconds after the ultraviolet irradiation is stopped, the light transmittance of the temporary antiglare region 22 containing the diarylethene derivative A exceeds 80%, and the temporary antiglare region 22 becomes almost colorless (colorless).

[0072] For example, when ultraviolet light having a wavelength of 550 nm is irradiated onto a windshield 11 in which the normal antiglare region 21 contains diarylethene derivative B, the light transmittance when the ultraviolet light irradiation is stopped is about 5%, similar to diarylethene derivative A, but the color gradual decrease time of the normal antiglare region 21 containing diarylethene derivative B is about 30 seconds. After the ultraviolet light irradiation is stopped, the light transmittance of the normal antiglare region 21 exceeds 80% in 55 to 60 seconds, and the normal antiglare region 21 becomes almost colorless (colorless).

[0073] In this way, the diarylethene derivative A used in the temporary antiglare region 22 has a color fading time that is 1 / 15 of that of the diarylethene derivative B, i.e., a decolorization speed that is 15 times faster than that of the diarylethene derivative B. Therefore, the diarylethene derivative A can be suitably used in the temporary antiglare region 22 including the point P1 indicating the reference position of the driver's line of sight, which must be restored to a transparent state immediately after the irradiation of ultraviolet light is stopped in order to ensure visibility.

[0074] Furthermore, since diarylethene derivative B has a longer color fade time than diarylethene derivative A (15 times longer), the colored state of normal antiglare region 21 can be maintained with fewer irradiation times than temporary antiglare region 22. The number of irradiation times indicates the length of ultraviolet irradiation time. In other words, the colored state of normal antiglare region 21 can be maintained with shorter irradiation times than temporary antiglare region 22. In this way, diarylethene derivative B can be suitably used for normal antiglare region 21, which does not include point P1 indicating the reference point for the driver's eye position, and which is required to continuously maintain a colored state to provide antiglare while driving vehicle 1, reduce the amount of ultraviolet irradiation to contribute to energy savings, and suppress deterioration of the windshield.

[0075] Furthermore, since the light-reverting photochromic material's light transmittance is restored (decolorized) by light (visible light, infrared light) after UV irradiation has stopped, the decolorization speed is not affected by temperature (outside temperature, etc.) Therefore, when a driver requires good visibility, for example, while driving on a curved road, the light transmittance is quickly restored by irradiation with strong sunlight, etc.

[0076] In this embodiment, for example, “DAE1,” “DAE12,” or “DAE18” (all manufactured by Yamada Chemical Co., Ltd.) can be used as a light-return type (photoisomer type) photochromic material for the dimming component 20. Of these, one with a slow decolorization speed can be used for the normal antiglare region 21, and one with a fast decolorization speed can be used for the temporary antiglare region 22.

[0077] Next, a heat-return type (T-type) photochromic material will be described. There are no particular limitations on the heat-return type photochromic compound used in the light-adjusting component 20, but photochromic compounds such as spiro compounds (spiropyran, spirooxazine) can be used. Even when a heat-return type photochromic material is used in the light-adjusting component 20, it is sufficient to use a material with a slow decolorization rate in the normal antiglare region 21 and a material with a fast decolorization rate in the temporary antiglare region 22.

[0078] For example, as shown in reaction formula (4) below, when a spiro compound is irradiated with ultraviolet light (or light containing ultraviolet light, such as sunlight), it isomerizes from a closed-ring form to a ring-open form, becoming a metastable merocyanine and becoming colored. The merocyanine returns to its stable original closed-ring form and loses color when exposed to light or heat. In other words, the ultraviolet ring-opening reaction caused by the action of light and the ring-closing reaction caused by the exposure of light or heat occur reversibly, causing the optical state to change between a colored state and a transparent state.

[0079]

[0080] In this embodiment, for example, "TCP-0054," "TCP-0021," "TCP-0024," and "TCP-0033" (all manufactured by Yamada Chemical Co., Ltd.) can be used as a heat-reversible (thermal bleaching) photochromic material for the light-adjusting component 20. Of these, one with a slow bleaching speed can be used for the normal antiglare region 21, and one with a fast bleaching speed can be used for the temporary antiglare region 22.

[0081] Here, an example of the coloring / decoloring behavior of a heat-returning photochromic material will be described using Figures 4A and 4B. Figure 4A is a diagram showing an example of the coloring behavior of a heat-returning photochromic material, and Figure 4B is a diagram showing an example of the decoloring behavior of the same heat-returning photochromic material as Figure 4A. In Figures 4A and 4B, the transmitted light intensity of visible light (wavelength 550 nm in this example) related to the level of light transmittance is shown on the vertical axis, and the passage of time is shown on the horizontal axis. This example shows an example of the behavior (change in optical state) of a heat-returning photochromic material in which the increase in light transmittance is relatively gradual.

[0082] In the example shown in FIG. 4A, a 200 μm thick PMMA resin film containing a thermal photochromic material was irradiated with ultraviolet light at a temperature of 30° C. and a visible light wavelength of 550 nm. The irradiation intensity of the ultraviolet light was 3.6 mW / cm ２ Furthermore, a heat-reverting photochromic material, TCP-0033 manufactured by Yamada Chemical Industry Co., Ltd., was added to the PMMA resin film in an amount equivalent to 5 wt % relative to the PMMA resin.

[0083] 4A, if UV irradiation is started at time t1, 5 seconds after the start of measurement of the transmitted light intensity, the transmitted light intensity will be reduced to almost half (approximately 0.5) 10 seconds after time t1 (15 seconds after the start of measurement). If UV irradiation is continued further, the transmitted light intensity will be very low, at approximately 0.2 to 0.3, 40 seconds after time t1 (45 seconds after the start of measurement).

[0084] 4B shows the decolorization behavior of the heat-reversible photochromic material when UV irradiation of the PMMA resin film in the example of FIG. 4A is stopped. As shown in FIG. 4B, after UV irradiation is stopped at time t2, the transmitted light intensity is very weak at 0.2. However, it gradually increases, reaching approximately 0.5 after 100 seconds and recovering to 0.8 after 400 seconds. For the heat-reversible photochromic material of this example, the time until the transmitted light intensity exceeds 0.5 (the color gradual decrease time) is approximately 100 seconds. In other words, even after UV irradiation is stopped, the anti-glare colored state is maintained for approximately 100 to 150 seconds.

[0085] In this way, heat-reverting photochromic materials with a gradual increase in light transmittance can be suitably used in the normal anti-glare area 21, which does not include point P1, which indicates the reference point for the driver's line of sight, and which is required to continuously maintain a colored state while the vehicle 1 is in operation to provide anti-glare, while reducing the amount of ultraviolet radiation to contribute to energy savings and to prevent deterioration of the windshield.

[0086] Furthermore, a heat-return photochromic material with a faster increase in light transmittance may be used for the temporary anti-glare region 22, which includes point P1, indicating the reference position of the driver's line of sight, and which must be restored to a transparent state immediately after UV irradiation is stopped to ensure visibility. For example, the light control device 10 may be equipped with a heating device (heater) to more quickly increase the light transmittance in the temporary anti-glare region 22. For example, after a certain period of UV irradiation, the temporary anti-glare region 22 may be heated by the heating device, thereby increasing the decolorization speed of the heat-return photochromic material and quickly increasing the light transmittance.

[0087] The heat-returning photochromic material restores its light transmittance (decolorizes) due to temperature change after UV irradiation has stopped. Therefore, even in situations where visible light or infrared light is not irradiated (for example, inside a tunnel or at night), irradiation with visible light or the like is not required to restore (decolorize) its light transmittance. Therefore, it can be suitably used for anti-glare protection against light sources other than sunlight (such as light emitted by lighting fixtures), and can further contribute to energy savings. Furthermore, the windshield 11 may use both a light-returning photochromic material and a heat-returning photochromic material. Specifically, a light-returning photochromic material may be used in the normal anti-glare region 21 and a heat-returning photochromic material in the temporary anti-glare region 22, or a heat-returning photochromic material may be used in the normal anti-glare region 21 and a light-returning photochromic material in the temporary anti-glare region 22. When a light-returning photochromic material and a heat-returning photochromic material are used in combination, it is sufficient that the decolorization speed of the normal antiglare area 21 is slower than that of the temporary antiglare area 22 .

[0088] Next, the configuration of the light irradiating unit 30 and the manner in which ultraviolet light is irradiated onto the windshield 11 will be described with reference to FIGS. 5A and 5B.

[0089] 5A , the UV light source unit 31 of the light irradiation unit 30 may be a line light source that irradiates ultraviolet light 31 d in a line. The UV light source unit 31, which is a line light source, irradiates a portion of the surface 11 a of the windshield 11, and the irradiation areas 21 d, 22 d are linear. When the UV light source unit 31 is a line light source, the light irradiation unit 30 may be provided in an area near the upper end of the windshield 11 on the ceiling 2.

[0090] In this example, the light irradiation unit 30 irradiates the upper region 111 (normal anti-glare region 21) of the windshield 11 with a linear ultraviolet ray 31d from the UV light source unit 31. This allows the normal anti-glare region 21 to be efficiently colored. In this example, the light irradiation unit 30 may also scan the entire surface (surface 11a) of the windshield 11 with the ultraviolet ray 31d. For example, under the control of the control unit 70, the light irradiation unit 30 rotates a movable member vertically to change the irradiation angle of the ultraviolet ray 31d and scans the ultraviolet ray 31d. This allows each region to be colored with lower illuminance than when the upper region 111 and the non-upper region 112 are irradiated without scanning the ultraviolet ray, thereby contributing to energy savings. Furthermore, when a linear light source is used as the UV light source unit 31, the irradiation regions 21d and 22d are linear, eliminating the need for alignment during irradiation (such as determining an effective anti-glare position or the driver's eye position). This reduces the control load on the control unit 70.

[0091] As shown in FIG. 5B , the UV light source 31 of the light irradiation unit 30 may be a spot light source that irradiates spot-shaped ultraviolet rays 31c. In this case, the ultraviolet rays emitted by the UV light source 31 are locally irradiated onto the surface 11a of the windshield 11, and the irradiation areas 21a, 22a are preferably circular and have a diameter of approximately 10 to 20 cm. The light irradiation unit 30 can scan the spot-shaped ultraviolet rays within the upper area 111 (see FIG. 2A ) of the windshield 11, which corresponds to the normal anti-glare area 21. For example, under the control of the control unit 70, the light irradiation unit 30 rotates the UV light source 31 left and right to change the irradiation angle of the spot-shaped ultraviolet rays. As a result, the spot-shaped ultraviolet rays 31c scans along a trajectory 131 from the irradiation area 21a, which is the upper right edge of the windshield 11 (normal anti-glare area 21), to the upper left edge of the windshield 11 (normal anti-glare area 21). This minimizes the colored area of ​​the windshield 11, thereby ensuring maximum visibility for the driver and reducing glare.

[0092] The light irradiation unit 30 can scan the entire surface 11a of the windshield 11 with spot-shaped ultraviolet light. For example, under the control of the control unit 70, the light irradiation unit 30 rotates the UV light source unit 31 left and right and up and down to change the irradiation angle of the spot-shaped ultraviolet light. As a result, the spot-shaped ultraviolet light 31c scans along a trajectory 131 from the irradiation area 21a, which is the upper right edge of the windshield 11 (normal anti-glare area 21), to the irradiation area 22a, which is the lower left edge of the windshield 11 (temporary anti-glare area 22). Therefore, the normal anti-glare area 21 and the temporary anti-glare area 22 can be colored as needed. Note that the scanning mode of the spot-shaped ultraviolet light 31c is not limited to this, and it may also be scanned from the upper left edge to the lower right edge of the windshield 11. By scanning the surface 11a of the windshield 11 with the ultraviolet light 31c, the entire upper area 111 can be colored at low illuminance, contributing to energy savings.

[0093] (Operation) Next, the operation of the light control device 10 will be described with reference to Fig. 6. The operation of the light control device 10 shown in the flowchart of Fig. 6 starts, for example, at the same time as the power switch of the vehicle is turned ON, and ends when the power switch is turned OFF. While the power switch is in the ON state, the control unit 70 periodically controls the irradiation of ultraviolet light onto the normal anti-glare area 21 by the light irradiation unit 30.

[0094] In step S601, the data acquisition unit 71 of the control unit 70 checks whether a predetermined time has passed since the previous control process (S601), and if it determines that the predetermined time has passed and that it is time to execute the control process (Yes in S601), it acquires an illuminance signal indicating the outdoor illuminance from the external illuminance measurement unit 60 (S602) and outputs it to the irradiation control unit 72. If the data acquisition unit 71 determines that the predetermined time has not passed (No in S601), it waits until the predetermined time has passed.

[0095] The external illuminance measuring unit 60 may transmit the illuminance signal in response to a request from the data acquiring unit 71, or the external illuminance measuring unit 60 may voluntarily transmit the illuminance signal to the data acquiring unit 71 in accordance with the cycle of the control process. The data acquiring unit 71 may also output data for determining the driving state (the states of the main switch and the shift lever) to the irradiation control unit 72 together with the illuminance signal.

[0096] The illumination control unit 72 determines whether the outdoor illumination indicated by the input illumination signal is equal to or greater than a predetermined value (S603). The predetermined value may be, for example, an average daytime illumination value or a brightness that does not require turning on the headlights. If the illumination control unit 72 determines that the outdoor illumination is equal to or greater than the predetermined value (Yes in S603), it reads the dimming data 81 corresponding to the outdoor illumination from the storage unit 80 (S604).

[0097] Specifically, the illumination control unit 72 reads the illumination mode (illuminance and number of illuminations) of the dimming data 81 corresponding to the outdoor illuminance, and generates a control signal indicating the illumination mode and the illumination range (normal anti-glare area 21). For example, the illuminance in the illumination mode of the dimming data 81 may be set appropriately according to the outdoor illuminance.

[0098] The irradiation control unit 72 transmits the generated control signal (irradiation mode, irradiation range) to the drive unit 32 of the light irradiation unit 30, and controls the light irradiation unit 30 to irradiate ultraviolet light based on the control signal (S605). As a result, the light irradiation unit 30 irradiates ultraviolet light onto the normal anti-glare area 21 (upper area 111) of the windshield 11 in an irradiation mode that corresponds to the outdoor illuminance. In other words, the change in the transmittance of the windshield 11 is controlled based on the irradiation mode (illuminance, number of irradiations) read by the control unit 70.

[0099] On the other hand, if the irradiation control unit 72 determines that the outdoor illuminance is less than the specified value (No in S603), it sends a control signal to the drive unit 32 of the light irradiation unit 30, indicating that ultraviolet light irradiation should be stopped (S606). This allows the light irradiation unit 30 to stop emitting ultraviolet light in response to a decrease in outdoor illuminance due to weather changes or the passage of time, thereby reducing unnecessary energy consumption. Note that the light adjustment data 81 may be configured not to include the number of irradiations, and instead, the light irradiation unit 30 may irradiate ultraviolet light every time the photochromic material in the normal antiglare region 21 gradually decreases (e.g., approximately 30 seconds for a light-return type (P-type) or approximately 100 seconds for a heat-return type (T-type)) until ultraviolet light irradiation is stopped in step S607. This reduces the amount of data in the light adjustment data 81.

[0100] Furthermore, for example, the specified value of outdoor illuminance used for the judgment in step S603 above may be stepped, and for example, the irradiation control unit 72 may include the temporary anti-glare area 22 as the ultraviolet irradiation range when the outdoor illuminance is equal to or greater than a predetermined first specified value and also equal to or greater than a second specified value indicating an illuminance higher than the first specified value (for example, when external light (sunlight, etc.) is very strong).

[0101] The number of irradiations in the irradiation mode of the temporary antiglare region 22 may be set to be greater than the number of irradiations in the irradiation mode of the normal antiglare region 21. For example, the number of irradiations in the light control data 81 is the number of times that the colored state of the windshield 11 (light transmittance of 50% or less) can be maintained within the execution interval (e.g., 60 seconds) of the control process. For example, if diarylethene derivative A is used in the temporary antiglare region 22, the number of irradiations in 60 seconds may be 15 times, with one irradiation per gradual decrease time (2 seconds). If diarylethene derivative B is used in the normal antiglare region 21, the number of irradiations in 60 seconds may be two times, with one irradiation per gradual decrease time (30 seconds). In this way, the irradiation mode of the light control data 81 may be stored in advance in the storage unit 80 according to the type of photochromic compound.

[0102] 7A and 7B , the configuration of a light control device according to a second embodiment of the present disclosure will be described. In the light control device according to the present disclosure, the configuration for measuring the amount of external light entering the vehicle interior 1 a is not limited to the external illuminance measuring unit 60.

[0103] As shown in Fig. 7B , the light control device 101 according to the second embodiment may include a light transmittance measuring unit 90 and a driver monitor 40. In Fig. 7A and Fig. 7B , the same components as those of the light control device 10 according to the first embodiment are denoted by the same reference numerals as those of the light control device 10, and the description thereof will be omitted.

[0104] The driver monitor 40 is a device that measures the brightness (illuminance) around the eyes of the driver in the vehicle interior 1a (specifically, the driver's seat 3). It is installed in a position that allows it to capture an image of the driver's face from below, for example, on top of the steering column 5. The driver monitor 40 includes an imaging unit (camera) (not shown) that acquires an image of the driver's face and analyzes the image to determine the illuminance around the driver's eyes. The driver monitor 40 can identify the position of the driver's eyes from the acquired facial image using known face recognition technology and calculate the illuminance of the area around the identified eye position. The driver monitor 40 transmits a driver illuminance signal indicating the measured illuminance around the driver's eyes (an example of the brightness of a predetermined area in the vehicle interior 1a) to the control unit 70. In addition to the dimming data 81, the memory unit 80 of the light control device 101 also stores dimming data 82 that associates the illuminance around the driver's eyes (driver illuminance) with the ultraviolet light irradiation pattern.

[0105] The light transmittance measuring unit 90 is a visible light transmittance measuring device that measures light transmittance by, for example, clamping the windshield 11. The light transmittance measuring unit 90 is made up of an upper light transmittance measuring unit 90a that measures the light transmittance of the upper region 111 of the windshield 11, and a non-upper light transmittance measuring unit 90b that measures the light transmittance of the non-upper region 112. The light transmittance measuring units 90 (upper light transmittance measuring unit 90a, non-upper light transmittance measuring unit 90b) send transmittance signals indicating the measured light transmittances (light transmittances of the upper region 111 and non-upper region 112) to the control unit 70.

[0106] In addition, in this embodiment, the memory unit 80 stores dimming data 82 in which light transmittance is associated with the ultraviolet light irradiation mode, and dimming data 83 in which driver illuminance is associated with the ultraviolet light irradiation mode.

[0107] Next, the operation (control process) of the light control device 101 including the driver monitor 40 and the light transmittance measuring unit 90 will be described with reference to Fig. 8. Only the operation different from the control process shown in Fig. 6 will be described in detail, and the description of the equivalent process will be omitted as appropriate.

[0108] In step S801, the control unit 70 performs the same process as in step S601. Next, the irradiation control unit 72 acquires a transmittance signal from the upper light transmittance measurement unit 90a via the data acquisition unit 71 (S802), and further acquires a transmittance signal from the non-upper light transmittance measurement unit 90b (S803). The transmittance signal may be transmitted by the light transmittance measurement unit 90 in response to a request from the data acquisition unit 71, or the light transmittance measurement unit 90 may transmit the transmittance signal to the data acquisition unit 71 voluntarily in accordance with the cycle of the control process in the light control device 101.

[0109] Next, the illumination control unit 72 determines whether the light transmittance indicated by the input transmittance signal is equal to or greater than a predetermined value (S804). Specifically, if the illumination control unit 72 determines based on the transmittance signal that the light transmittance of either the upper region 111 or the non-upper region 112 is equal to or greater than the predetermined value (Yes in S804), the illumination control unit 72 acquires a driver illuminance signal (illuminance around the driver's eyes) from the driver monitor 40 via the data acquisition unit 71 (S805). The predetermined light transmittance values ​​may be set individually for the upper region 111 and the non-upper region 112. In other words, different predetermined values ​​may be set for the upper region 111 and the non-upper region 112. This allows the upper region 111 and the non-upper region 112 to be individually controlled to light transmittances (light transmittances equal to or less than the predetermined value) appropriate for each region.

[0110] The driver monitor 40 may transmit the driver illuminance signal in response to a request from the data acquisition unit 71, or the driver monitor 40 may transmit the driver illuminance signal to the data acquisition unit 71 voluntarily in accordance with the cycle of the control process in the light control device 101. Furthermore, the data acquisition unit 71 may acquire the driver illuminance signal at the same timing as the acquisition of the transmittance signal (S802, S803).

[0111] The illumination control unit 72 determines whether the illuminance around the driver's eyes indicated by the acquired driver illuminance signal is equal to or greater than a predetermined value (S806). If the illumination control unit 72 determines that the illuminance indicated by the driver illuminance signal is equal to or greater than the predetermined value (Yes in S806), it reads the illumination modes of the light control data 82 corresponding to the light transmittance and the light control data 83 corresponding to the driver illuminance from the storage unit 80 (S807), derives an illumination mode for control based on the two types of illumination modes read, and generates a signal indicating the ultraviolet illumination range and a control signal indicating the illumination mode for control (S808). For example, the illumination control unit 72 calculates the average values ​​of the illuminance and the number of irradiations for each of the illumination modes of the light control data 82 and 83, and derives the average values ​​of the illuminance and the number of irradiations as the illumination mode for control.

[0112] The irradiation mode of the dimming data 82 according to the light transmittance may be stored in the storage unit 80 as long as it corresponds to each of the upper region 111 and the non-upper region 112. This allows the illuminance and number of irradiations of ultraviolet light to be changed for each of the upper region 111 and the non-upper region 112, thereby controlling each region to an appropriate light transmittance. The irradiation mode of the dimming data 82 may also be common to the upper region 111 and the non-upper region 112. In this case, the data content with the highest illuminance and the highest number of irradiations may be used as the common irradiation mode. This makes it possible to avoid insufficient illuminance or insufficient number of irradiations.

[0113] Furthermore, for example, the irradiation control unit 72 may set the ultraviolet irradiation area to be an area of ​​the upper region 111 or the non-upper region 112 whose light transmittance is equal to or greater than a specified value. Furthermore, when the illuminance around the eyes is equal to or greater than a specified value, both the upper region 111 and the non-upper region 112 may be set to be the irradiation range.

[0114] The irradiation control unit 72 transmits a control signal to the drive unit 32 of the light irradiation unit 30 in the same manner as in step S605 above, and controls the light irradiation unit 30 to irradiate ultraviolet light based on the control signal (S809). On the other hand, when the irradiation control unit 72 determines that the light transmittance of both the upper region 111 and the non-upper region 112 or the driver illuminance is less than the specified value (No in S804, No in S806), it transmits a control signal to the drive unit 32 of the light irradiation unit 30 instructing to stop irradiation of ultraviolet light in the same manner as in step S606 above (S810).

[0115] As described above, the light control device 101 according to this embodiment further includes a light transmittance measuring unit 90 and a driver monitor 40, the storage unit 80 stores light control data 82 associating light transmittance with an irradiation mode and light control data 83 associating driver illuminance with an irradiation mode, and the irradiation control unit 72 reads out from the storage unit 80 irradiation modes corresponding to the light transmittances acquired by the data acquisition unit 71 from the light transmittance measuring unit 90 (upper light transmittance measuring unit 90a, non-upper light transmittance measuring unit 90b) and the driver illuminances acquired by the data acquisition unit 71 from the driver monitor 40. Furthermore, the irradiation control unit 72 derives irradiation modes for control based on the read-out irradiation modes, and controls the irradiation of ultraviolet light by the light irradiation unit 30 based on the illuminance and the number of irradiations indicated by the derived irradiation modes.

[0116] This allows anti-glare to be performed according to the light transmittance of each region (upper region 111, non-upper region 112) of the windshield 11 and the brightness inside the vehicle cabin 1a (driving illuminance in this example). Furthermore, by acquiring the light transmittance of the upper region 111 and the non-upper region 112, it is also possible to provide anti-glare for light sources other than sunlight (for example, headlights of oncoming vehicles, lighting fixtures installed on the side of the road or on buildings, etc.).

[0117] Furthermore, the light control device 101 may not be provided with the driver monitor 40 and the light control data 83. In this case, the light control device 101 may control the irradiation of ultraviolet light, i.e., adjust the light inside the vehicle interior 1a, based on the measurement result (light transmittance of the windshield 11) of the light transmittance measurement unit 90 without performing the processes of steps S805 and S806. In other words, when the driver monitor 40 is not provided, the irradiation control unit 72 in the light control device 101 may read out from the storage unit 80 the irradiation mode of the light control data 82 corresponding to the light transmittance obtained from the light transmittance measurement unit 90, and control the light irradiation unit 30.

[0118] Effects of the Embodiments (1) The light control device 10 is a light control device for a vehicle that adjusts the amount of light incident into the vehicle interior 1a, and includes a vehicle windshield 11 containing a light control material that decreases its visible light transmittance in response to ultraviolet light and increases its visible light transmittance in response to at least one of visible light and heat, and a light irradiation unit 30 that irradiates the windshield 11 with ultraviolet light from inside the vehicle interior 1a, wherein the light control material contained in the upper region 111, which is the upper of the two regions obtained by dividing the windshield 11 into upper and lower halves, increases its visible light transmittance at a slower rate than the light control material contained in the non-upper region 112, which is the lower of the two regions. As a result, the non-upper region 112, which is within the driver's field of vision, quickly fades, ensuring the driver's field of vision of the vehicle 1, while the colored state of the upper region 111, which receives a large amount of sunlight, is maintained for a long time, reducing glare and suppressing the amount of ultraviolet light irradiation, contributing to energy conservation and suppressing deterioration of the windshield.

[0119] (2) In the light control device 10, the light-controlling material in the windshield 11 may be a photochromic material. This reversibly generates two isomers with different colors and absorption spectra, and allows the light transmittance of the windshield 11 including the light-controlling member 20 to be suitably controlled.

[0120] (3) The light-adjusting device 10 may use a photochromic material that increases visible light transmittance in response to heat as the light-adjusting material constituting the windshield. This allows the windshield 11 to lose its color and restore its light transmittance even when there is no external light, such as sunlight, irradiating it.

[0121] (4) The light control device 10 may use a photochromic material that reacts to visible light to increase the visible light transmittance as the light control material constituting the windshield 11. This allows the windshield 11 to be properly decolorized by sunlight or the like, restoring the light transmittance without being affected by the outside temperature.

[0122] (5) The photochromic material in the windshield 11 changes color in response to ultraviolet light, and the photochromic material constituting the upper region 111 may have a lower visible light transmittance when colored than the photochromic material constituting the non-upper region 112. This more reliably reduces the amount of sunlight incident on the upper region 111 of the windshield, where sunlight is more likely to be incident. Furthermore, the increase in light transmittance is appropriately suppressed in the non-upper region 112 (temporary anti-glare region 22) within the driver's field of vision, ensuring visibility.

[0123] (6) The upper region 111 of the windshield may be an area above the line of sight of the driver of the vehicle 1. This allows for continuous glare protection while maintaining good visibility for the driver while driving.

[0124] DESCRIPTION OF SYMBOLS 1...vehicle, 1a...vehicle interior, 2...ceiling, 3...driver's seat, 4...dashboard, 5...steering column, 10...light control device, 11...windshield, 12...transparent substrate, 13...specific light blocking member, 20...light control member, 21...normal anti-glare area, 22...temporary anti-glare area, 30...light irradiation unit, 31...UV light source unit, 32...drive unit, 40...driver monitor, 60...external illuminance measurement unit, 70...control unit, 71...data acquisition unit, 72...irradiation control unit, 80...storage unit, 81, 82, 83...light control data, 90...light transmittance measurement unit, 90a...upper light transmittance measurement unit, 90b...non-upper light transmittance measurement unit, 101...light control device, 110...side windshield, 111...upper area, 112...non-upper area

Claims

1. A dimming device for a vehicle that adjusts the amount of incident light into the vehicle interior, comprising: a vehicle windshield configured to include a dimming material that decreases in visible light transmittance in response to ultraviolet light and increases in visible light transmittance in response to at least one of visible light or heat; a light irradiation unit that irradiates the windshield with ultraviolet light from the vehicle interior; wherein the dimming material included in the upper first region among two regions obtained by dividing the windshield vertically has a slower rate of increase in visible light transmittance than the dimming material included in the lower second region of the same region.

2. The dimming device according to claim 1, wherein the dimming material is a photochromic material.

3. The dimming device according to claim 2, wherein a photochromic material that increases in visible light transmittance in response to heat is used as the dimming material constituting the windshield.

4. The dimming device according to claim 2, wherein a photochromic material that increases in visible light transmittance in response to visible light is used as the dimming material constituting the windshield.

5. The dimming device according to claim 2, wherein the dimming material is colored in response to ultraviolet light, and the dimming material constituting the first region has a lower visible light transmittance when colored than the dimming material constituting the second region.

6. The dimming device according to claim 5, wherein the first region of the windshield is a region above the line of sight of the driver of the vehicle.

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