Light control device

Abstract

A light control device (10) for a vehicle that adjusts the amount of light incident into a cabin (1a) comprises: a windshield (11) for a vehicle, the windshield (11) including a photochromic material that changes color in response to ultraviolet light and loses color in response to visible light or infrared light; and a light irradiation unit (30) that irradiates the windshield (11) with ultraviolet light from the inside of the cabin (1a). The photochromic material included in an upper region (111) that is above the center in the vertical direction in the windshield (11) loses color faster than the photochromic material included in a non-upper region (112) other than the upper region (111). When a vehicle (1) is in operation, the upper region (111) is set as an irradiation range of ultraviolet light from the light irradiation unit (30), and when the vehicle (1) is not in operation, the surface (11a) of the windshield (11) including the upper region (111) and the non-upper region (112) is set as the irradiation range.

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] On the other hand, it is necessary to maintain the windshield in a colored state (a state in which external light transmittance is reduced) when the vehicle is not being driven (for example, when the vehicle is parked) to suppress an increase in temperature inside the vehicle cabin. However, with the technology of Patent Document 1, the windshield instantly loses its color (its external light transmittance increases) when UV irradiation is stopped. Therefore, if the windshield is to remain colored, the amount of UV irradiation increases, and more energy is required to cool the UV light source.

[0006] The present disclosure aims to provide glare protection while ensuring visibility while driving a vehicle, suppress the rise in temperature inside the vehicle when not driving, and further reduce the amount of ultraviolet radiation to contribute to energy conservation.

[0007] One aspect of the present disclosure is a light control device for a vehicle that adjusts the amount of light entering a vehicle interior, the light control device comprising: a vehicle windshield containing a photochromic material that changes color in response to ultraviolet light and changes color in response to visible light or infrared light; and a light irradiation unit that irradiates ultraviolet light onto the windshield from inside the vehicle interior, wherein the photochromic material contained in a first region of the windshield that is above the center in the vertical direction fades faster than the photochromic material contained in a second region other than the first region, and when the vehicle is in operation, the first region is the irradiation range of ultraviolet light from the light irradiation unit, and when the vehicle is not in operation, the irradiation range is the entire windshield including the first region and the second region.

[0008] According to the present disclosure, it is possible to provide glare protection while ensuring visibility while driving a vehicle, suppress the rise in temperature inside the vehicle when not driving, and further reduce the amount of ultraviolet radiation, thereby contributing to energy conservation.

[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 showing an example of the configuration of a light irradiating unit in the light control device of the first embodiment; FIG. 8 is a diagram showing another example of the configuration of a light irradiating unit in the light control device of the first embodiment; FIG. 9 is a diagram showing yet another example of the configuration of a light irradiating unit in the light control device of the first embodiment; FIG. 10 is a diagram showing an example of the configuration of a plurality of light irradiating units in the light control device of the first embodiment; FIG. 11 is a diagram showing another example of the configuration of a plurality of light irradiating units in the light control device of the first embodiment; FIG. 1 is a block diagram showing an example of a schematic configuration of a light control device according to a first modified example of the second embodiment. FIG. 2 is a flowchart illustrating an example of the operation of the light control device according to the first modified example of the second embodiment. FIG. 3 is a block diagram showing another example of a schematic configuration of a light control device according to the first modified example of the second embodiment. FIG. 4 is a flowchart illustrating another example of the operation of the light control device according to the first modified example of the second embodiment. FIG. 5 is a block diagram showing an example of a schematic configuration of a light control device according to a second modified example of the second embodiment. FIG. 6 is a flowchart illustrating an example of the operation of the light control device according to the second modified example of the second 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 the external light transmittance. The windshield 11 has a multi-layer structure, and the light control member 20 is one of the multi-layers.

[0012] The light control member 20 is a sheet-like or plate-like member and is provided on the windshield 11. The light control member 20 is formed containing a photochromic compound (photochromic material) that has the optical property of changing color in response to ultraviolet light and changing color in response to visible light or infrared light. This gives the light control member 20 photoresponsiveness, whereby the light transmittance decreases when ultraviolet light (ultraviolet light) is received and increases when infrared light (infrared light) or visible light is received.

[0013] The light-adjusting member 20 has an anti-glare region 21 that mainly contributes to anti-glare, and a heat-shielding region 22 that contributes to suppressing temperature increases in the vehicle interior 1a. The anti-glare region 21 is a region that can be colored (a state in which external light transmittance is reduced) while the vehicle 1 is in operation, and the heat-shielding region 22 is a region that can be colored while the vehicle 1 is parked. In this embodiment, the photochromic material contained in the anti-glare region 21 and the photochromic material contained in the heat-shielding region 22 have different decolorization speeds. Details of the photochromic material will be described later.

[0014] The anti-glare area 21 is located above the center of the windshield 11 in the vertical direction (toward the ceiling 2), and the heat-shielding area 22 is located below the center of the windshield 11 in the vertical direction (toward the dashboard 4), i.e., an area other than the anti-glare area 21. The anti-glare area 21 corresponds to the upper area 111 of the windshield 11, and the heat-shielding area 22 corresponds to the non-upper area 112 of the windshield 11. Therefore, the anti-glare area 21 is colored by ultraviolet rays irradiated onto the upper area 111, and the heat-shielding area 22 is colored by ultraviolet rays irradiated onto the non-upper area 112.

[0015] 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 control member 20. The ultraviolet rays from the light irradiation unit 30 cause the windshield 11 (light control member 20) to become colored, reducing the external light transmittance and adjusting the light intensity inside 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.

[0016] 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.

[0017] That is, the light irradiation unit 30 changes whether or not the UV light source unit 31 emits ultraviolet rays and the irradiation mode of the ultraviolet rays (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 to rotate the UV light source unit 31. That is, the light irradiation unit 30 changes the irradiation angle of the ultraviolet rays from the UV light source unit 31, i.e., the irradiation range. In this way, the light irradiation unit 30 can irradiate ultraviolet rays onto either or both of the upper region 111 and the non-upper region 112 of the windshield 11, thereby appropriately coloring the anti-glare region 21 and the heat-shielding region 22.

[0018] 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 making it possible to change the irradiation range in a more diverse manner.

[0019] 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.

[0020] 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.

[0021] 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).

[0022] The control unit 70 controls the light control for the interior of the vehicle cabin 1a by controlling the change in the external light transmittance of the windshield 11. For example, the control unit 70 controls the UV irradiation range (colored area of ​​the windshield 11) from the light irradiation unit 30 based on whether the vehicle 1 is in operation. The control unit 70 also reads out the irradiation mode, including the UV illuminance and number of irradiations, from the memory unit 80 and controls the UV irradiation by the light irradiation unit 30 based on the illuminance and number of irradiations indicated by the irradiation mode. The number of irradiations indicates the length of the UV irradiation time. In other words, controlling the number of irradiations corresponds to controlling the UV irradiation time. Note that the irradiation time per UV irradiation may be a fixed value, or the irradiation mode may include the irradiation time per irradiation. The control unit 70 supplies control signals indicating the irradiation mode and irradiation range to the drive unit 32 of the light irradiation unit 30. As a result, the light irradiation unit 30 irradiates the UV light to the irradiation range indicated by the control signal according to the irradiation mode indicated by the control signal. The control unit 70 may also supply a control signal to the drive unit 32 of the light irradiation unit 30 to control whether or not the UV light source unit 31 emits ultraviolet light.

[0023] 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.

[0024] 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 preferably set to a numerical range in consideration of the amount of data in the light adjustment data 82.

[0025] Next, an information processing circuit included in the control unit 70 will be described. The control unit 70 includes a data acquisition unit 71 and an illumination 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 illumination control unit 72. For example, the data acquisition unit 71 acquires an illuminance signal indicating the external illuminance from the external illuminance measurement unit 60, and outputs the signal to the illumination control unit 72. The data acquisition unit 71 also acquires the states of the main switch and shift lever related to starting the engine of the vehicle 1, and outputs the signal to the illumination control unit 72.

[0026] 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.

[0027] 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 external light transmittance of the windshield 11 according to various environmental conditions, thereby adjusting the light inside the vehicle interior 1a.

[0028] The irradiation control unit 72 also controls the irradiation range of the ultraviolet light emitted by the light irradiation unit 30 (the colored area on the windshield 11) according to the driving state of the vehicle 1. The driving state is divided into a driving state indicating that the vehicle is being driven and a non-driving state indicating that the vehicle is not being driven (parked).

[0029] The illumination control unit 72 determines the driving state of the vehicle 1 based on, for example, the states of the main switch and the range of the shift lever input from the data acquisition unit 71. For example, the illumination control unit 72 determines 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 met, and determines that the vehicle 1 is in a non-driving state when these conditions are not met. The main switch is, for example, a vehicle power supply if the vehicle 1 is an electric vehicle, an ignition switch if the vehicle 1 is an engine vehicle, or at least one of the engine and motor switches if the vehicle 1 is a hybrid vehicle equipped with an engine and a motor.

[0030] When the vehicle 1 is in a driving state, it is necessary for the driver to be able to see the environment outside the vehicle from inside the passenger compartment 1a. Therefore, when the vehicle 1 is in a driving state, the control unit 70 determines the irradiation range of ultraviolet light from the light irradiation unit 30 to be the upper region 111 of the windshield 11. Meanwhile, when the vehicle 1 is not in a driving state, it is not necessary for the driver to see the environment outside the vehicle. Therefore, when the vehicle 1 is not in a driving state, the control unit 70 determines the irradiation range of ultraviolet light from the light irradiation unit 30 to be the upper region 111 and 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").

[0031] 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.

[0032] As described above, in the light control device 10, the windshield 11 contains a photochromic material, and the windshield 11 is colored and its external light transmittance is appropriately adjusted by ultraviolet irradiation performed by the light irradiation 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 external light transmittance of the light control member 20, thereby controlling the light in the vehicle interior 1a.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] The light-adjusting member 20 is disposed rearward of the specific light-blocking member 13, i.e., on the vehicle interior 1a side. The light-adjusting member 20 is made of a resin composition containing a photochromic compound. The light-adjusting member 20 is a sheet- or plate-shaped member whose base material is, for example, PVB resin blended with the photochromic compound.

[0037] 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).

[0038] The area of ​​the anti-glare region 21 in the light-adjusting member 20 is smaller than the heat-shielding region 22. For example, the width (height) H of the anti-glare region 21 in the vertical direction is smaller than the width H of the windshield 11 in the vertical direction. １is preferably within 20%. This minimizes the colored area of ​​the windshield 11 while the vehicle 1 is in operation, ensuring the driver's visibility to the extent that the environment outside the vehicle can be seen while reducing glare. Furthermore, the colored state of the antiglare region 21 and the heat-shielding region 22 is preferably in a state in which the external light transmittance is 50% or less of that when the antiglare region 21 and the heat-shielding region 22 are in a decolorized (colorless) state. This reliably reduces the glare felt by the driver while the vehicle 1 is in operation, and reliably suppresses the temperature rise inside the vehicle interior 1a while the vehicle 1 is parked. The external light transmittance when colored can be appropriately adjusted by the content of the photochromic compound and the thickness of the light-adjusting component 20.

[0039] 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 vehicle interior 1a. In this case, the light-adjusting member 20 is attached to the surface of the transparent substrate 12 facing the vehicle interior 1a. When installed in the vehicle interior 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 installation 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 ) that are provided on the left and right sides of the windshield 11 and contain a photochromic compound. In this case, the side windshields 110 may contain a photochromic compound that, like the heat-shielding region 22, exhibits a slow decoloring rate, contributing to suppressing temperature increases in the vehicle interior 1a.

[0040] Next, the manner in which ultraviolet rays are irradiated onto the windshield 11 will be described. In the light control device 10 according to this embodiment, when the vehicle 1 is in a driving state, the upper region 111 of the surface 11a of the windshield 11 is the irradiation range of ultraviolet rays from the light irradiator 30, and when the vehicle 1 is not in a driving state, the entire surface 11a of the windshield 11 is the irradiation range of ultraviolet rays from the light irradiator 30. That is, the light irradiator 30 irradiates ultraviolet rays 31a onto the upper region 111 (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 (anti-glare region 21 and heat-shielding region 22) when the vehicle is not in a driving state as shown in Fig. 3B.

[0041] 3A , when the vehicle 1 is in operation, only the anti-glare region 21 is colored, and the external light transmittance is reduced only in the upper region 111, thereby reducing glare while ensuring the driver's field of view. Furthermore, when the vehicle 1 is not in operation, the anti-glare region 21 and the heat-shielding region 22 are colored, reducing the external light transmittance of the entire windshield 11. This significantly reduces the amount of external light entering the vehicle interior 1a, thereby suppressing a rise in temperature within the vehicle interior 1a. As described above, the control unit 70 determines the irradiation range depending on the driving state, and under the control of the control unit 70, the movable member of the light irradiation unit 30 rotates to irradiate the determined irradiation range with ultraviolet light.

[0042] Next, the photochromic compound used in the light-adjusting component 20 will be described. A photochromic compound is a compound whose molecular structure changes under the action of light or heat, reversibly generating two isomers with different colors and absorption spectra. In this embodiment, the light-adjusting component 20 uses a light-return (P-type) photochromic compound that has high thermal stability and whose molecular structure changes reversibly only under the action of light. There are no particular limitations on the light-return photochromic compound used in the light-adjusting component 20, but examples of photochromic compounds that can be used include diarylethene-based and fulgide-based photochromic compounds.

[0043] 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.

[0044]

[0045] As described above, the photochromic compounds contained in the antiglare region 21 and the heat-shielding region 22 are different. In this embodiment, the antiglare region 21 (upper region 111 of the windshield 11) of the light-adjusting member 20 contains a photochromic compound that has a faster decolorization rate than the heat-shielding region 22 (non-upper region 112). Therefore, the external light transmittance of the antiglare region 21 increases quickly after ultraviolet light irradiation, making it possible to quickly ensure the driver's visibility while reducing glare.

[0046] Furthermore, the heat-shielding region 22 contains a photochromic compound that fades more slowly than the anti-glare region 21, and therefore maintains its colored state longer than the anti-glare region 21, even after UV irradiation has stopped. This reduces the UV illuminance and number of irradiations required to maintain the colored state compared to when the same photochromic compound as the anti-glare region 21 is used. Reducing the number of irradiations means reducing the irradiation time. Therefore, reducing the illuminance and number of irradiations reduces the cumulative amount of UV light (= illuminance x irradiation time) required to maintain the colored state, contributing to energy conservation. While the vehicle 1 is parked, the light control device 10 can maintain the colored state of the windshield 11 and suppress temperature increases in the passenger compartment 1a while reducing the amount of UV irradiation (cumulative amount of light).

[0047] For example, the antiglare region 21 can use a diarylethene derivative (reaction formula (2) below) in which the substituent R in the reaction formula (1) is a cyano group.

[0048]

[0049] For example, the heat-shielding region 22 can use a diarylethene derivative (reaction formula (3) below) in which the substituent R in the reaction formula (1) above is a methyl group.

[0050]

[0051] 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).

[0052] For example, when ultraviolet light with a wavelength of 550 nm is irradiated onto a windshield 11 in which the antiglare region 21 contains diarylethene derivative A, the external light transmittance is approximately 5% when the ultraviolet light irradiation is stopped, at which point the degree of coloring of the antiglare region 21 reaches a maximum (external light transmittance is minimum). After the ultraviolet light irradiation is stopped, the degree of coloring of the antiglare region 21 gradually decreases (external light transmittance gradually increases), and it takes approximately 2 seconds for the external light transmittance to reach 50% (coloration gradual decrease time). Approximately 5 seconds after the ultraviolet light irradiation is stopped, the external light transmittance of the antiglare region 21 containing the diarylethene derivative A exceeds 80%, and the antiglare region 21 becomes almost colorless (colorless).

[0053] For example, when ultraviolet light having a wavelength of 550 nm is irradiated onto a windshield 11 in which the heat-shielding region 22 contains diarylethene derivative B, the ambient light transmittance when the UV irradiation is stopped is about 5%, similar to that of diarylethene derivative A, but the color gradual decrease time of the heat-shielding region 22 containing diarylethene derivative B is about 30 seconds. After the UV irradiation is stopped, the ambient light transmittance of the heat-shielding region 22 exceeds 80% in 55 to 60 seconds, and the heat-shielding region 22 becomes almost colorless (colorless).

[0054] As described above, the color fading time of the diarylethene derivative A is 1 / 15 of that of the diarylethene derivative B, i.e., the color fading speed is 15 times that of the diarylethene derivative B. Therefore, the diarylethene derivative A can be suitably used in the antiglare region 21 which must immediately return to a transparent state after the cessation of ultraviolet irradiation in order to ensure visibility.

[0055] Furthermore, since the color fading time of diarylethene derivative B is longer than that of diarylethene derivative A (15 times longer), the colored state of heat-shielding region 22 can be maintained with fewer irradiation times than that of anti-glare region 21. The number of irradiation times indicates the length of the ultraviolet irradiation time. In other words, the colored state of heat-shielding region 22 can be maintained with shorter irradiation times than that of anti-glare region 21. In this way, diarylethene derivative B can be suitably used in heat-shielding region 22, which requires preventing a temperature rise in vehicle interior 1a while parked, while contributing to energy savings by suppressing the amount of ultraviolet irradiation.

[0056] 4A to 4C, the configuration of the light irradiator 30 and the manner in which ultraviolet light is irradiated onto the windshield 11 will be described. As shown in Fig. 4A, for example, the light control device 10 includes one or more light irradiators 30. In other words, it is sufficient that at least one light irradiator 30 is installed in the vehicle interior 1a.

[0057] As shown in FIG. 4A , the light control device 10 may include an intermediate member 150. The intermediate member 150 is a member that controls the distribution of transmitted ultraviolet light. The intermediate member 150 is disposed between the light irradiation unit 30 and the windshield 11 and is capable of adjusting the irradiation range of ultraviolet light from the UV light source unit 31. The intermediate member 150 is, for example, a plate-shaped member and can be attached to the ceiling 2 inside the vehicle interior 1a or the light irradiation unit 30 (in front of the UV light source unit 31). The intermediate member 150 has a light collection region 151 that collects and emits ultraviolet light from the light irradiation unit 30, and a diffusion region 152 that diffuses and emits ultraviolet light from the light irradiation unit 30.

[0058] For example, the light-collecting region 151 may be a condensing lens, or the surface 151a may be subjected to a surface treatment (for example, fine irregularities that concentrate incident light within a predetermined range) that condenses the ultraviolet light emitted by the UV light source unit 31. The diffusion region 152 may be a diffusion plate made of a diffusing lens, or the surface 152a may be subjected to a surface treatment (for example, fine irregularities that cause ultraviolet light to be incident at various (random) angles of incidence) that diffuses the ultraviolet light emitted by the UV light source unit 31.

[0059] 4A , light irradiation unit 30 irradiates upper region 111 of windshield 11 with ultraviolet light 151b via light-collecting region 151, and irradiates non-upper region 112 of windshield 11 with ultraviolet light 152b via diffusion region 152. As a result, when vehicle 1 is in operation, ultraviolet light is irradiated only onto upper region 111, reliably coloring anti-glare region 21. Furthermore, when vehicle 1 is not in operation, ultraviolet light can be irradiated onto the entire surface 11a of windshield 11 without significantly changing the irradiation direction (irradiation angle) of UV light source unit 31, thereby efficiently coloring anti-glare region 21 and heat-shielding region 22.

[0060] As shown in FIG. 4B , 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 with a diameter of approximately 10 to 20 cm. In this example, the light irradiation unit 30 irradiates spot-shaped ultraviolet rays onto the irradiation area 21a, which is a portion of the upper region 111 (a portion of the surface 11a) of the windshield 11, when the vehicle 1 is in operation. This minimizes the colored area of ​​the windshield 11 when the vehicle is in operation, thereby reducing glare while ensuring maximum visibility for the driver.

[0061] The position of the illumination area 21 a in the upper area 111 may be the intersection of a light source of external light (e.g., the sun) and the driver's eyes. The intersection is identified by the control unit 70 based on the eye position acquired by the driver monitor 40 (described later) and the position of the external light source acquired by the light source identification unit 50 (described later).

[0062] Furthermore, when the vehicle 1 is not driving, the light irradiation unit 30 scans 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 corner of the windshield 11 (anti-glare area 21), to the irradiation area 22a, which is the lower left corner of the windshield 11 (heat-shielding area 22). This allows the anti-glare area 21 and the heat-shielding area 22 to be colored when the vehicle 1 is not driving. Note that the scanning pattern of the spot-shaped ultraviolet light 31c is not limited to this, and it may also be scanned from the upper left corner to the lower right corner of the windshield 11. By scanning the surface 11a of the windshield 11 with the ultraviolet light 31c, the entire upper area 111 is colored at low illuminance, contributing to energy savings.

[0063] Furthermore, during driving, the light irradiating unit 30 may scan the upper region 111 of the windshield 11 with spot-shaped ultraviolet light. In this case, the control unit 70 does not need to identify the intersection point.

[0064] 4C , 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 b, 22 b 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.

[0065] In this example, when the vehicle 1 is in a driving state, the light irradiation unit 30 scans a line of ultraviolet light 31d from the UV light source unit 31 within the upper region 111 (anti-glare region 21) of the windshield 11. When the vehicle 1 is not in a driving state, the light irradiation unit 30 scans the entire surface (surface 11a) of the windshield 11 with ultraviolet light 31d. For example, under the control of the control unit 70, the light irradiation unit 30 rotates the movable member vertically to change the irradiation angle of the ultraviolet light 31d and scans the ultraviolet light 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 light, thereby contributing to energy savings. Furthermore, when a line-shaped light source is used as the UV light source unit 31, it is not necessary to identify the driver's line of sight, unlike when a spot-shaped light source is used, and therefore the control load on the control unit 70 can be reduced.

[0066] 4A to 4C , the illuminance of the ultraviolet light irradiated onto the upper region 111 from the light irradiator 30 to the windshield 11 may be higher than that of the ultraviolet light irradiated onto the non-upper region 112. This stabilizes the colored state of the antiglare region 21, which is easily decolorized (fast decolorization rate). Furthermore, by reducing the illuminance of the ultraviolet light irradiated onto the non-upper region 112 compared to the upper region 111, the entire surface 11a of the windshield 11 can be colored when the vehicle is not driving, while contributing to energy savings.

[0067] For example, based on a control signal from the control unit 70, the light irradiation unit 30 may set the illuminance of the ultraviolet light when irradiating the anti-glare area 21 to be higher than that of the heat-shielding area 22. In the example shown in Fig. 4A, the light irradiation unit 30 may be configured so that the illuminance of the ultraviolet light irradiating the anti-glare area 21 is increased by condensing the ultraviolet light 151b that passes through the light-condensing area 151 of the intermediate member 150.

[0068] Furthermore, for example, the light control device 10 may include multiple (e.g., two) light irradiation units 30. As shown in FIG. 5A , for example, the light irradiation unit 30 may include a first light irradiation unit 30a that irradiates the anti-glare region 21 (upper region 111) with ultraviolet light and a second light irradiation unit 30b that irradiates the heat-shielding region 22 (non-upper region 112) with ultraviolet light. In the light irradiation unit 30 configured as described above, when the vehicle 1 is in a driving state, the first light irradiation unit 30a irradiates ultraviolet light 31e, and when the vehicle 1 is parked, the first light irradiation unit 30a and the second light irradiation unit 30b irradiate ultraviolet light (ultraviolet light 31e, 31f). As a result, when the vehicle 1 is in a driving state, ultraviolet light is irradiated only onto the anti-glare region 21, and when the vehicle 1 is parked, ultraviolet light is irradiated onto both the anti-glare region 21 and the heat-shielding region 22 (the entire surface 11a of the windshield 11).

[0069] 5B , the light irradiation unit 30 may be configured such that the first light irradiation unit 30a has a linear light source as the UV light source unit 31 that irradiates the upper region 111 with linear ultraviolet rays 31g, and the second light irradiation unit 30b has a spot light source as the UV light source unit 31 that irradiates the non-upper region 112 with spot ultraviolet rays 31h. When the vehicle 1 is in a driving state, the upper region 111 is irradiated with ultraviolet rays 31g, and when the vehicle 1 is not in a driving state, the upper region 111 is irradiated with ultraviolet rays 31g and the non-upper region 112 is irradiated with ultraviolet rays 31h.

[0070] In the light control device 10 shown in Fig. 5B, the irradiation area 21g of ultraviolet light 31g emitted by the first light irradiator 30a is wider than the irradiation area 21b (see Fig. 4C) and may correspond to the entire anti-glare area 21. Furthermore, the irradiation area 22h of ultraviolet light 31h emitted by the second light irradiator 30b is wider than the irradiation area 22a (see Fig. 4B) and may correspond to the entire heat-shielding area 22.

[0071] 5B , the irradiation area 21g of the ultraviolet light 31g may be the same as the irradiation area 21b (see FIG. 4C ), and the irradiation area 21h of the ultraviolet light 31h may be the same as the irradiation area 22a (see FIG. 4B ). In this case, the first light irradiation unit 30a may scan the ultraviolet light 31g within the antiglare area 21, and the second light irradiation unit 30b may scan the ultraviolet light 31h within the heat-shielding area 22.

[0072] 5B , the UV light source unit 31 of the first light irradiation unit 30a may irradiate the antiglare region 21 with ultraviolet light of a higher illuminance than the UV light source unit 31 of the second light irradiation unit 30b. This allows the antiglare region 21, which has a fast decolorization rate, to be uniformly irradiated with ultraviolet light of a higher illuminance, thereby stabilizing the colored state. Furthermore, the heat-shielding region 22 can be uniformly irradiated with ultraviolet light of a lower illuminance, thereby contributing to energy savings and maintaining the colored state of the heat-shielding region 22.

[0073] Although not shown, the UV light source unit 31 in each of the two light irradiation units (the first light irradiation unit 30a and the second light irradiation unit 30b) may be a line-shaped light source. In this case, the second light irradiation unit 30b may be provided on either the left or right A-pillar 6 in the vehicle interior 1a, and may scan a line of ultraviolet light in the left-right direction within the heat-shielding area 22.

[0074] (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 an accessory switch of a vehicle is turned ON, and ends when the accessory switch is turned OFF. While the accessory switch is in the ON state, the control unit 70 periodically controls the irradiation of ultraviolet light by the light irradiation unit 30.

[0075] 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.

[0076] 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 transmit the illuminance signal to the data acquiring unit 71 on its own initiative in accordance with the cycle of the control process. The data acquiring unit 71 also outputs 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.

[0077] The irradiation control unit 72 determines whether the outdoor illuminance indicated by the input illuminance signal is equal to or greater than a predetermined value (S603). If the irradiation control unit 72 determines that the outdoor illuminance is equal to or greater than the predetermined value (Yes in S603), the irradiation control unit 72 determines the ultraviolet ray irradiation range according to the driving state (driving state or non-driving state) determined based on the states of the master switch and the shift lever, and generates a control signal indicating the irradiation range (S604). The predetermined value may be, for example, an average daytime illuminance value, or a brightness that does not require turning on the headlights.

[0078] The illumination control unit 72 reads the dimming data 81 corresponding to the outdoor illuminance from the storage unit 80 (S605). Specifically, the illumination control unit reads the illumination mode (illuminance and number of irradiations) of the dimming data 81 corresponding to the outdoor illuminance and generates a control signal indicating the illumination mode. For example, the illuminance in the illumination mode of the dimming data 81 may be set appropriately according to the outdoor illuminance. Furthermore, for example, the illumination mode of the dimming data 81 may be divided into an illumination mode for the anti-glare area 21 and an illumination mode for the heat-shielding area 22, and the illumination control unit 72 may select the illumination mode based on the illumination range determined in step S604. In this case, the illuminance of the illumination mode for the anti-glare area 21 may be set higher than the illuminance of the illumination mode for the heat-shielding area 22.

[0079] The number of irradiations in the irradiation mode of the antiglare region 21 may be set to be greater than the number of irradiations in the irradiation mode of the heat-shielding region 22. For example, the number of irradiations in the light-adjusting data 81 is the number of times that the colored state of the windshield 11 (external 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 antiglare region 21, the number of irradiations in 60 seconds may be 15 times, with one irradiation every gradual decrease time (2 seconds). If diarylethene derivative B is used in the heat-shielding region 22, the number of irradiations in 60 seconds may be two times, with one irradiation every gradual decrease time (30 seconds). In this way, the irradiation mode of the light-adjusting data 81 may be stored in advance in the storage unit 80 according to the type of photochromic compound.

[0080] 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 (S606). As a result, the light irradiation unit 30 irradiates ultraviolet light onto the windshield 11 in an irradiation mode that corresponds to the outdoor illuminance and an irradiation range that corresponds to the driving state. 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, and the colored region (colored area) of the windshield 11 is controlled based on the irradiation range determined by the control unit 70.

[0081] 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 radiation irradiation should be stopped (S607). This allows the light irradiation unit 30 to stop emitting ultraviolet radiation 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 irradiation mode in the dimming data 81 may not include the number of irradiations, and the light irradiation unit 30 may irradiate ultraviolet radiation at gradually decreasing intervals (e.g., 2 seconds) until ultraviolet radiation irradiation is stopped in step S607. This allows the amount of data in the dimming data 81 to be reduced.

[0082] Second Embodiment (Configuration) The configuration of a light control device according to a second embodiment of the present disclosure will be described with reference to Figures 7A and 7B. In the light control device according to the present disclosure, the configuration for measuring the amount of external light entering the vehicle interior 1a is not limited to the external illuminance measurement unit 60. For example, the light control device according to the present disclosure may include at least one of a driver monitor 40, a light source identification unit 50, an external illuminance measurement unit 60, and an internal illuminance measurement unit 90. Of these, the driver monitor 40 and the internal illuminance measurement unit 90 correspond to a vehicle interior illuminance measurement unit 200 that measures the brightness of a predetermined area in the vehicle interior 1a.

[0083] The light control device 101 according to the second embodiment may include an external illuminance measuring unit 60 and a vehicle interior illuminance measuring unit 200 (driver monitor 40) as shown in Fig. 7B . 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.

[0084] 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.

[0085] Next, the operation (control process) of the light control device 101 including the driver monitor 40 and the external illuminance measuring unit 60 will be described with reference to Fig. 8A. Only the operations different from the control process shown in Fig. 6 will be described in detail, and the description of equivalent processes will be omitted as appropriate. The control process shown in Fig. 8A is a process using the driver monitor 40, and is performed in the light control device 101 when the vehicle is driving (when the driver is in the driver's seat). When the light control device 101 is not driving, the same process as the control process shown in Fig. 6 is performed.

[0086] The control unit 70 performs the same processes as those of steps S601 to S603 in steps S801 to S803. When the irradiation control unit 72 determines that the outdoor illuminance is equal to or greater than a specified value (Yes in S803), it acquires a driver illuminance signal from the driver monitor 40 via the data acquisition unit 71 (S804). The illuminance signal may be transmitted by the driver monitor 40 in response to a request from the data acquisition unit 71, or the driver monitor 40 may voluntarily transmit the illuminance signal to the data acquisition unit 71 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 illuminance signal (S802).

[0087] 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 (S805). 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 S805), it reads out the illumination modes of the light control data 81 corresponding to the external illuminance and the light control data 82 corresponding to the driver illuminance from the storage unit 80, derives a control illumination mode based on the two read illumination modes, and generates a control signal indicating the control illumination mode (S807). For example, the illumination control unit 72 calculates the average values ​​of the illuminance and the number of irradiations for the illumination modes of the light control data 81 and 82, and derives the average values ​​of the illuminance and the number of irradiations as the control illumination mode.

[0088] 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 S606 above, and controls the light irradiation unit 30 to irradiate ultraviolet rays based on the control signal (S808). On the other hand, if the irradiation control unit 72 determines that the outdoor illuminance or the driver illuminance is less than the specified value (No in S803, No in S805), it transmits a control signal to the drive unit 32 of the light irradiation unit 30 instructing to stop irradiating ultraviolet rays in the same manner as in step S607 above (S809).

[0089] As described above, the light control device 101 according to this embodiment further includes a vehicle interior illuminance measurement unit 200 (driver monitor 40) in addition to the external illuminance measurement unit 60. The storage unit 80 stores light control data 82 that associates driver illuminance with illumination modes. In a driving state, the illumination control unit 72 reads from the storage unit 80 illumination modes corresponding to the outdoor illuminance acquired by the data acquisition unit 71 from the external illuminance measurement unit 60 and the driver illuminance acquired by the data acquisition unit 71 from the driver monitor 40. The illumination control unit 72 further derives an illumination mode for control based on the read illumination modes, and controls the illumination of ultraviolet light by the light illumination unit 30 based on the illuminance and the number of illuminations indicated by the derived illumination mode. As a result, in a driving state, glare prevention can be performed according to the outdoor brightness and the brightness inside the vehicle interior 1a (driving illuminance in this example).

[0090] Furthermore, the operation of the light control device 101 in the driving state is not limited to the example shown in FIG. 8A . Another example of the operation of the light control device 101 in the driving state is shown in FIG. 8B . When the data acquisition unit 71 determines that a predetermined time has elapsed since the previous processing (Yes in S811), as in step S801, the data acquisition unit 71 acquires the brightness around the eyes (driver illuminance) from the driver monitor 40 (S812), as in step S804. When the data acquisition unit 71 determines that the driver illuminance is equal to or greater than a predetermined value (Yes in S813), the data acquisition unit 71 reads the illumination mode of the light control data 82 corresponding to the driver illuminance from the storage unit 80 and generates a control signal indicating the illumination mode (S814). As in step S808, the illumination control unit 72 transmits the control signal to the drive unit 32 of the light illumination unit 30 and controls the light illumination unit 30 to irradiate ultraviolet light based on the control signal (S815). On the other hand, if the irradiation control unit 72 determines that the driver illuminance is less than the specified value (No in S813), it sends a control signal indicating the stopping of ultraviolet irradiation to the drive unit 32 of the light irradiation unit 30, as in S809 above (S816).

[0091] In this way, in the dimming device 101, when the vehicle 1 is in a driving state, the illumination control unit 72 may read out from the memory unit 80 the illumination mode of the dimming data 82 corresponding to the illuminance (brightness) around the eyes obtained from the driver monitor 40.

[0092] (First Modification) An example of a first modification of the light control device 101 according to the second embodiment will be described with reference to FIGS. 7A , 9A , and 9B . As shown in FIG. 9A , the light control device 101 may include an internal illuminance measurement unit 90 as the vehicle interior illuminance measurement unit 200. The internal illuminance measurement unit 90 includes an illuminance meter and measures the brightness (illuminance) inside the vehicle interior 1a (inside the vehicle interior space). The internal illuminance measurement unit 90 may be installed at any position inside the vehicle interior 1a. For example, similar to the external illuminance measurement unit 60, the internal illuminance measurement unit 90 may be installed at a lower portion of the windshield 11 on the vehicle interior 1a side (e.g., on the instrument panel). The internal illuminance measurement unit 90 transmits a signal (internal illuminance signal) indicating the illuminance inside the vehicle interior 1a (internal illuminance) to the control unit 70. In this modification, the memory unit 80 stores light control data 83 that associates internal illuminance with ultraviolet light irradiation modes.

[0093] Next, the operation (control process) of the dimmer 101 including the internal illuminance measurement unit 90 will be described with reference to FIG. 9B . When the control unit 70 (data acquisition unit 71) determines that a predetermined time has elapsed since the previous control process (Yes in S901), as in step S601 above, the control unit 70 acquires an internal illuminance signal from the internal illuminance measurement unit 90 (S902) and outputs it to the irradiation control unit 72. The internal illuminance signal may be transmitted by the internal illuminance measurement unit 90 in response to a request from the data acquisition unit 71, or the internal illuminance measurement unit 90 may transmit the internal illuminance signal to the data acquisition unit 71 voluntarily in accordance with the cycle of the control process in the dimmer 101. As in step S602 above, the data acquisition unit 71 outputs data for determining the operating state to the irradiation control unit 72 together with the internal illuminance signal.

[0094] The irradiation control unit 72 determines whether the internal illuminance indicated by the input internal illuminance signal is equal to or greater than a predetermined value (S903). If the irradiation control unit 72 determines that the internal illuminance is equal to or greater than the predetermined value (Yes in S903), it determines the ultraviolet irradiation range as in step S604 and generates a control signal indicating the irradiation range (S904). Next, the irradiation control unit 72 reads the irradiation mode of the dimming data 83 corresponding to the internal illuminance from the storage unit 80, generates a control signal indicating the irradiation mode (S905), and transmits the generated control signal (irradiation mode, irradiation range) to the drive unit 32 of the light irradiation unit 30 to control the ultraviolet irradiation by the light irradiation unit 30 (S906). On the other hand, if the irradiation control unit 72 determines that the internal illuminance is less than the predetermined value (No in S903), it transmits a control signal to the drive unit 32 of the light irradiation unit 30 to stop ultraviolet irradiation (S907).

[0095] In this way, the dimming device 101 is provided with an internal illuminance measuring unit 90 that measures the brightness (internal illuminance) of the space within the vehicle interior 1a, the memory unit 80 stores dimming data 83 that associates the internal illuminance with the ultraviolet light irradiation mode, and the control unit 70 (irradiation control unit 72) may read out the irradiation mode of the dimming data 83 corresponding to the internal illuminance from the memory unit 80.

[0096] Next, another example of the first modified example of the light control device 101 will be described with reference to Figures 7A, 9C, and 9D. As shown in Figure 9C, the light control device 101 may be configured to include an external illuminance measurement unit 60 and a vehicle interior illuminance measurement unit 200 (an internal illuminance measurement unit 90). In this case, the storage unit 80 may store, in addition to the light control data 83, light control data 81 that associates the external illuminance with the ultraviolet light irradiation mode.

[0097] 9D shows the operation (control process) of the light control device 101 in another example of the first modified example. The operation of the light control device 101 is the same as the operation of the light control device 101 shown in FIG. 8A except that the interior illuminance measurement unit 90 is used as the vehicle interior illuminance measurement unit 200 and the illumination range is set (S916). The process related to the interior illuminance measurement unit 90 is the same as the operation of the light control device 101 shown in FIG. 9B. The processes of steps S911 to S913 are the same as steps S801 to S803, and the processes of steps S914 to S916 are the same as steps S902 to S904. The processes of steps S917 to S920 are the same as steps S806 to S809, except that the illumination mode of the light control data 83 corresponding to the illuminance (internal illuminance) in the vehicle interior 1a is read in instead of the light control data 82.

[0098] As described above, the light control device 101 according to this embodiment further includes a vehicle interior illuminance measurement unit 200 (internal illuminance measurement unit 90) in addition to the external illuminance measurement unit 60, the storage unit 80 stores light control data 83 that associates internal illuminance with an irradiation mode, and in a driving state, the irradiation control unit 72 may read, from the storage unit 80, irradiation modes of light control data (light control data 81, 83) corresponding to the outdoor illuminance acquired by the data acquisition unit 71 from the external illuminance measurement unit 60 and the internal illuminance acquired by the data acquisition unit 71 from the internal illuminance measurement unit 90. Furthermore, the irradiation control unit 72 may derive an irradiation mode for control based on each of the read-out irradiation modes, and control ultraviolet irradiation by the light irradiation unit 30 based on the illuminance and the number of irradiations indicated by the derived irradiation mode.

[0099] 7A , 10A, and 10B, a second modification of the light control device 101 according to the second embodiment will be described. As shown in FIG. 10A, the light control device 101 may include a light source identification unit 50.

[0100] The light source identification unit 50 identifies the position of a light source (e.g., sunlight, lighting devices such as headlights of oncoming vehicles) present outside the vehicle. The light source identification unit 50 includes an imaging unit 51, which is a camera that captures an image of the outside of the vehicle, and a luminance measurement unit 52 that measures the luminance of the captured image (external image). The light source identification unit 50 determines that a light source is present in a pixel portion of the external image whose luminance value is equal to or greater than a predetermined luminance value, and identifies the relative position of the light source (light source position) based on the position of the light source on the external image and the mounting angle and mounting position of the imaging unit 51 within the vehicle interior 1a. The light source identification unit 50 then transmits a luminance signal indicating the luminance of the identified light source position in the external image, i.e., the luminance of the light source, to the control unit 70. The luminance value indicated by the luminance signal also indicates the degree of tinting of the windshield 11. In this example, the light control device 101 determines that the lower the luminance value, the higher the degree of tinting (lower external light transmittance), and that the higher the luminance value, the lower the degree of tinting (higher external light transmittance).

[0101] In this example, the storage unit 80 of the light control device 101 only needs to store light control data 84 that associates the brightness of the light source with the irradiation mode of ultraviolet light. Furthermore, the light source identifying unit 50 may be installed, for example, on the upper part of the windshield 11 as shown in FIG. 7A , or may be installed in the light irradiating unit 30. The light source identifying unit 50 transmits the position of the identified light source to the control unit 70. The light source identifying unit 50 may use a camera for detecting obstacles ahead and objects such as a preceding vehicle for an ADAS (Advanced Driver-Assistance Systems) equipped in the vehicle.

[0102] Next, the operation (control process) of the dimmer 101 including the light source identifying unit 50 will be described with reference to Fig. 10B . When the control unit 70 (data acquisition unit 71) determines that a predetermined time has elapsed since the previous control process (Yes in S1001), as in step S601 above, the control unit 70 acquires a luminance signal from the light source identifying unit 50 (S902) and outputs the luminance signal to the illumination control unit 72. The light source identifying unit 50 may transmit the luminance signal in response to a request from the data acquisition unit 71, or the light source identifying unit 50 may transmit the luminance signal to the data acquisition unit 71 voluntarily in accordance with the cycle of the control process in the dimmer 101. Furthermore, as in step S602 above, the data acquisition unit 71 outputs data for determining the operating state to the illumination control unit 72 together with the luminance signal.

[0103] The illumination control unit 72 determines whether the luminance indicated by the input luminance signal is equal to or greater than a specified value (S1003). If the illumination control unit 72 determines that the luminance is equal to or greater than the specified value, i.e., that the degree of tinting of the windshield 11 is insufficient (Yes in S1003), the illumination control unit 72 generates a control signal indicating the ultraviolet ray irradiation range and sets the irradiation range, as in step S604 (S1004). Next, the illumination control unit 72 reads the irradiation mode of the light source luminance-dependent dimming data 84 from the storage unit 80 and generates a control signal indicating the irradiation mode (S1005), and transmits the generated control signal (illumination mode, irradiation range) to the drive unit 32 of the light irradiator 30 to control the ultraviolet ray irradiation by the light irradiator 30 (S1006). On the other hand, if the irradiation control unit 72 determines that the brightness of the light source is less than the specified value, i.e., that the degree of coloring of the windshield 11 is sufficient (or that there is no need to color the windshield 11) (No in S1003), it sends a control signal to the drive unit 32 of the light irradiation unit 30 indicating that the irradiation of ultraviolet rays should be stopped (S1007).

[0104] As described above, the light source identification unit 50 according to the second modification includes the light source identification unit 50 that identifies the position of a light source present outside the vehicle 1 and measures the luminance of the light source. The storage unit 80 stores the light control data 84 that associates the luminance of the light source with the ultraviolet light irradiation mode. The control unit 70 (illumination control unit 72) may read the irradiation mode of the light source luminance, which is the light source control data 83, from the storage unit 80. This allows the light control unit 101 to control the ultraviolet light irradiation by the light irradiation unit 30 according to the luminance of the light source (the degree of coloring of the windshield 11), thereby controlling the light in the vehicle interior 1a while suppressing excessive ultraviolet light irradiation. Furthermore, similar to the example in which the vehicle interior illuminance measurement unit 200 and the external illuminance measurement unit 60 are used in combination, the light source identification unit 50 and the external illuminance measurement unit 60 may be used in combination. In this case, the storage unit 80 may store the light control data 81 and the light control data 84.

[0105] (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 a vehicle compartment 1a, and includes a windshield 11 for the vehicle containing a photochromic material that changes color in response to ultraviolet light and loses color in response to visible light or infrared light, and a light irradiation unit 30 that irradiates the windshield 11 with ultraviolet light from inside the vehicle compartment 1a, in which the photochromic material contained in an upper region 111, which is above the center in the vertical direction of the windshield 11, loses color faster than the photochromic material contained in a non-upper region 112, and when the vehicle 1 is in operation, the upper region 111 is set as the irradiation range of ultraviolet light from the light irradiation unit 30, and when the vehicle 1 is not in operation, the irradiation range is the surface 11a of the windshield 11 including the upper region 111 and the non-upper region 112. This reduces glare while ensuring the driver's visibility when the vehicle 1 is in operation, suppresses an increase in the temperature inside the vehicle when not in operation, and further reduces the amount of ultraviolet light irradiation, contributing to energy conservation.

[0106] (2) The light control device 10 may include one or more light irradiators 30, and the illuminance of the ultraviolet light irradiated from the light irradiators 30 onto the windshield 11 to the upper region 111 may be higher than that of the ultraviolet light irradiated onto the non-upper region 112. This stabilizes the colored state of the anti-glare region 21, contributes to energy savings, and allows the entire surface 11a of the windshield 11 to be colored when the vehicle 1 is not in operation.

[0107] (3) The light control device 10 further includes an intermediate member 150 that is disposed between the light irradiation unit 30 and the windshield 11 and that can adjust the irradiation range of ultraviolet rays from the light irradiation unit 30. The light irradiation unit 30 is singular, and the intermediate member 150 has a light-concentrating region 151 that concentrates and emits ultraviolet rays from the light irradiation unit 30 and a diffusion region 152 that diffuses and emits the ultraviolet rays from the light irradiation unit 30. The light irradiation unit 30 may irradiate ultraviolet rays 151b to the upper region 111 via the light-concentrating region 151 and irradiate ultraviolet rays 152b to the non-upper region 112 via the diffusion region 152. In this way, when the vehicle 1 is in a driving state, ultraviolet rays are irradiated only to the upper region 111, and the anti-glare region 21 can be reliably colored. Furthermore, when the vehicle 1 is not in operation, ultraviolet light can be evenly irradiated onto the entire surface 11a of the windshield 11 without significantly changing the direction (irradiation angle) of ultraviolet light from the UV light source unit 31, thereby efficiently coloring the anti-glare area 21 and the heat-shielding area 22.

[0108] (4) The light irradiation unit 30 may have a spot light source as the UV light source unit 31 that irradiates spot-shaped ultraviolet rays 31c. When the vehicle 1 is in operation, the ultraviolet rays 31c may be irradiated onto a portion of the upper region 111, and when the vehicle 1 is not in operation, the ultraviolet rays 31c may scan the surface 11a of the windshield 11. This minimizes the colored area of ​​the windshield 11 when the vehicle 1 is in operation, thereby reducing glare while maximizing the driver's visibility. Furthermore, when the vehicle 1 is not in operation, the entire upper region 111 may be colored at low illuminance, contributing to energy savings.

[0109] (5) The light irradiation unit 30 of the light control device 10 may have a linear light source as the UV light source unit 31 that irradiates ultraviolet light in a line. When the vehicle 1 is in operation, the linear ultraviolet light 31d may scan the upper region 111, and when the vehicle 1 is not in operation, the ultraviolet light 31d may scan the surface 11a of the windshield 11. This allows each region of the windshield 11 (the upper region 111, the non-upper region 112) to be colored with low illuminance, contributing to energy savings. Furthermore, unlike when a spot light source is used, there is no need to identify the driver's line of sight, which reduces the control load on the control unit 70.

[0110] (6) The light control device 10 may include a plurality of light irradiation units 30, each of which includes a first light irradiation unit 30a that irradiates the upper region 111 with ultraviolet light 31e and a second light irradiation unit 30b that irradiates the non-upper region 112 with ultraviolet light 31f. When the vehicle 1 is in operation, only the first light irradiation unit 30a may irradiate the ultraviolet light 31e. When the vehicle 1 is not in operation, the first light irradiation unit 30a and the second light irradiation unit 30b may irradiate the ultraviolet light 31e and 31f, respectively. This allows the irradiation mode (illuminance, number of irradiations, etc.) between the upper region 111 and the non-upper region 112 to be easily and reliably changed. Furthermore, the first light irradiation unit 30a and the second light irradiation unit 30b corresponding to each region (upper region 111, non-upper region 112) of the windshield 11 can irradiate the entire surface 11a of the windshield 11 with ultraviolet light evenly when the vehicle is not in operation, thereby efficiently coloring the anti-glare region 21 and the heat-shielding region 22. (7) The first light irradiating unit 30a of the light control device 10 may have a linear light source as the UV light source unit 31 that irradiates the upper region 111 with linear ultraviolet rays 31g, and the second light irradiating unit 30b may have a spot light source as the UV light source unit 31 that irradiates the entire non-upper region 112 with spot-shaped ultraviolet rays 31h, so that when the vehicle 1 is in operation, the first light irradiating unit 30a irradiates the upper region 111 with ultraviolet rays 31g, and when the vehicle 1 is not in operation, the first light irradiating unit 30a irradiates the upper region 111 with ultraviolet rays 31g and the second light irradiating unit 30b irradiates the non-upper region 112 with ultraviolet rays 31h. This eliminates the need for the light irradiating unit 30 to scan the ultraviolet rays when coloring the antiglare region 21 and the heat-shielding region 22, thereby reducing the control load on the control unit 70 for the rotating members. (8) The light control device 10 may further include a memory unit 80 that stores a plurality of irradiation modes, each including an ultraviolet ray illuminance and a number of irradiations, and a control unit 70 that reads the irradiation mode from the memory unit 80 and controls the irradiation of ultraviolet rays by the light irradiation unit 30 based on the illuminance and the number of irradiations indicated by the irradiation mode. This allows reliable control of the ultraviolet ray irradiation by the light irradiation unit 30, thereby enabling highly accurate dimming of the vehicle interior 1a.

[0111] (9) The light control device 10 may further include an external illuminance measurement unit 60 that measures the brightness outside the vehicle 1, and the memory unit 80 may store ultraviolet light irradiation modes associated with the external brightness, and the control unit 70 may read out the irradiation mode corresponding to the external brightness from the memory unit 80. This allows the light irradiation by the light irradiation unit 30 to be controlled according to the intensity of external light, changing the external light transmittance of the windshield 11 and controlling the light inside the passenger compartment 1a with the minimum necessary amount of ultraviolet light irradiation. (10) The light control device 101 may further include, in addition to the external illuminance measurement unit 60, a passenger compartment illuminance measurement unit 200 (driver monitor 40 or interior illuminance measurement unit 90) that measures the brightness of a predetermined area inside the passenger compartment 1a (driver illuminance or interior illuminance), and the memory unit 80 may further store light control data (light control data 82, 83) that associates the brightness of the predetermined area inside the passenger compartment 1a with the irradiation mode. At this time, the control unit 70 may read from the storage unit 80 the irradiation mode of the dimming data 81 corresponding to the external illuminance and the irradiation mode of the dimming data (dimming data 82, 83) corresponding to the brightness of the predetermined area in the vehicle interior 1a, derive an irradiation mode for control based on each of the read irradiation modes, and control the irradiation of ultraviolet light by the light irradiation unit 30 based on the illuminance and number of irradiations indicated by the irradiation mode for control. In this way, the dimming device 101 can adjust the dimming inside the vehicle interior 1a by appropriate ultraviolet irradiation according to the external light conditions outdoors and inside the vehicle interior 1a, and can contribute to energy conservation by minimizing the amount of ultraviolet light irradiation by the light irradiation unit 30 while taking into consideration not only the external illuminance but also the brightness inside the vehicle interior 1a. (11) The light control device 101 further includes a driver monitor 40 that measures the brightness around the eyes of the driver of the vehicle 1 (driver illuminance), and the storage unit 80 stores light control data 82 that associates the driver illuminance with an ultraviolet light irradiation mode. When the vehicle 1 is in operation, the control unit 70 may read out from the storage unit 80 an irradiation mode corresponding to the driver illuminance acquired from the driver monitor 40. In this way, by using the light control data 82 while the vehicle 1 is in operation, the light control device 101 can adjust the light level in the vehicle interior 1a by appropriately irradiating ultraviolet light according to the glare perceived by the driver (driver illuminance), thereby minimizing the amount of ultraviolet light irradiated by the light irradiator 30 and contributing to energy conservation.Furthermore, the control unit 70 does not need to acquire the outdoor illuminance (step S802 above) or derive the irradiation mode for control (step S807 above), thereby reducing the processing load. (12) The light control device 101 may include an internal illuminance measurement unit 90 that measures the brightness of the space within the vehicle interior 1a (internal illuminance), the storage unit 80 may store light control data 83 that associates the internal illuminance with the irradiation mode of ultraviolet light, and the control unit 70 (irradiation control unit 72) may read out the irradiation mode of the light control data 83 corresponding to the internal illuminance from the storage unit 80. In this way, the light control device 101 can adjust the light within the vehicle interior 1a by appropriately irradiating ultraviolet light according to the driver illuminance (the glare perceived by the driver) by using the light control data 83, and the amount of ultraviolet light irradiation by the light irradiation unit 30 can be kept to a necessary minimum, contributing to energy conservation. (13) The light control device 101 may further include a light source identification unit 50 that identifies the position of a light source present outside the vehicle 1 and measures the luminance of the light source, the storage unit 80 may store light control data 84 that associates the luminance with an irradiation mode of ultraviolet light, and the control unit 70 may read out from the storage unit 80 the irradiation mode of the light control data 84 that corresponds to the luminance acquired from the light source identification unit 50. In this way, by using the light control data 84, the light control device 101 can adjust the light level in the vehicle interior 1a by appropriately irradiating ultraviolet light according to the luminance of the external light source, thereby contributing to energy conservation by minimizing the amount of ultraviolet light irradiation by the light irradiation unit 30.

[0112] DESCRIPTION OF SYMBOLS 1...vehicle, 1a...vehicle compartment, 2...ceiling, 3...driver's seat, 4...dashboard, 5...steering column, 6...A-pillar, 10...light control device, 10...diameter, 11...windshield, 12...transparent substrate, 13...specific light blocking member, 20...light control member, 21...anti-glare area, 22...heat blocking area, 30...light irradiation section, 30a...first light irradiation section, 30b...second light irradiation section, 31...UV light source section, 32...drive section, 40...driver monitor, 50...external light transmitting section Transmittance, 50...light source identification unit, 51...imaging unit, 52...luminance measurement unit, 60...external illuminance measurement unit, 70...control unit, 71...data acquisition unit, 72...illumination control unit, 80...storage unit, 81, 82, 83, 84...light control data, 90...internal illuminance measurement unit, 101...light control device, 110...side windshield, 111...upper region, 112...non-upper region, 150...intermediate member, 151...light collection region, 152...diffusion region, 200...vehicle interior illuminance measurement unit

Claims

1. A dimming device for a vehicle that adjusts the amount of incident light into the vehicle interior, comprising: a vehicle windshield including a photochromic material that colors in response to ultraviolet light and fades in response to visible light or infrared light; a light irradiation unit that irradiates the windshield with ultraviolet light from the vehicle interior; wherein, in the windshield, the photochromic material included in a first region that is above the center in the vertical direction fades faster than the photochromic material included in a second region other than the first region; when the vehicle is in operation, the first region is set as the irradiation range of the ultraviolet light from the light irradiation unit; when the vehicle is not in operation, the entire surface of the windshield including the first region and the second region is set as the irradiation range.

2. The dimming device according to claim 1, wherein the light irradiation unit is single or plural, and the illuminance of the ultraviolet light irradiated on the first region among the ultraviolet light irradiated on the windshield from the light irradiation unit is higher than that of the ultraviolet light irradiated on the second region.

3. The dimming device according to claim 1, further comprising an intermediate member disposed between the light irradiation unit and the windshield and capable of adjusting the irradiation range, wherein the light irradiation unit is single, the intermediate member has a light condensing region that condenses and emits the ultraviolet light from the light irradiation unit and a diffusion region that diffuses and emits the ultraviolet light from the light irradiation unit, the light irradiation unit irradiates the first region with ultraviolet light through the light condensing region and irradiates the second region with ultraviolet light through the diffusion region.

4. The dimming device according to claim 1, wherein the light irradiation unit has a spot-shaped light source that irradiates spot-shaped ultraviolet light, when the vehicle is in operation, a part of the first region is irradiated with the spot-shaped ultraviolet light, when the vehicle is not in operation, the entire surface of the windshield is scanned by the spot-shaped ultraviolet light.

5. The dimming device according to claim 1, wherein the light irradiation unit has a line-shaped light source that irradiates line-shaped ultraviolet light, when the vehicle is in operation, the line-shaped ultraviolet light scans within the first region, when the vehicle is not in operation, the entire surface of the windshield is scanned by the line-shaped ultraviolet light.

6. The light irradiation units are plural and include a first light irradiation unit that irradiates ultraviolet rays to the first region and a second light irradiation unit that irradiates ultraviolet rays to the second region. When the vehicle is in operation, only the first light irradiation unit irradiates ultraviolet rays. When the vehicle is not in operation, the first light irradiation unit and the second light irradiation unit irradiate ultraviolet rays. The light control device according to claim 1.

7. The first light irradiation unit has a linear light source that irradiates linear ultraviolet rays to the first region. The second light irradiation unit has a spot light source that irradiates spot-shaped ultraviolet rays to the entire second region. When the vehicle is in operation, the first light irradiation unit irradiates the linear ultraviolet rays to the first region. When the vehicle is not in operation, the first light irradiation unit irradiates the linear ultraviolet rays to the first region, and the second light irradiation unit irradiates the spot-shaped ultraviolet rays to the second region. The light control device according to claim 6.

8. The light control device according to any one of claims 1 to 7 further includes a storage unit that stores a plurality of irradiation modes including the illuminance and irradiation times of ultraviolet rays, and a control unit that reads out the irradiation mode from the storage unit and controls the irradiation of ultraviolet rays by the light irradiation unit based on the illuminance and irradiation times indicated by the irradiation mode.

9. The light control device according to claim 8 further includes an external illuminance measurement unit that measures the brightness outside the vehicle. The storage unit stores the irradiation mode in association with the brightness outside. The control unit reads out the irradiation mode corresponding to the brightness outside from the storage unit.

10. The light control device according to claim 9 further includes a vehicle interior illuminance measurement unit that measures the brightness of a predetermined region inside the vehicle. The storage unit stores the brightness of the predetermined region inside the vehicle in association with the irradiation mode. The control unit reads out the irradiation mode corresponding to each of the brightness outside and the brightness of the predetermined region inside the vehicle from the storage unit, derives a control irradiation mode based on each read irradiation mode, and controls the irradiation of ultraviolet rays by the light irradiation unit based on the illuminance and irradiation times indicated by the control irradiation mode.

11. The lighting control device according to claim 8, further comprising a driver monitor that measures the brightness around the eyes of the driver of the vehicle, wherein the storage unit stores the brightness around the eyes in association with the irradiation mode, and the control unit reads out the irradiation mode corresponding to the brightness around the eyes acquired from the driver monitor from the storage unit when the vehicle is in operation.

12. The lighting control device according to claim 8, further comprising an internal illuminance measurement unit that measures the brightness of the space inside the vehicle compartment, wherein the storage unit stores the brightness inside the vehicle compartment in association with the irradiation mode, and the control unit reads out the irradiation mode corresponding to the brightness inside the vehicle compartment acquired from the internal illuminance measurement unit from the storage unit.

13. The lighting control device according to claim 8, further comprising a light source identification unit that identifies the position of a light source existing outside the vehicle and measures the luminance of the light source, wherein the storage unit stores the luminance in association with the irradiation mode, and the control unit reads out the irradiation mode corresponding to the luminance acquired from the light source identification unit from the storage unit.

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