Liquid crystal panel unit and light irradiation device

Abstract

This liquid crystal panel unit is provided with a liquid crystal panel, a container, and a liquid. The accommodating body accommodates the liquid crystal panel, and has an entrance port through which light from the outside is incident to the liquid crystal panel, and an exit port through which the light from the liquid crystal panel is emitted to the outside. The liquid is translucent, has a refractive index closer to the liquid crystal panel than air, and immerses the liquid crystal panel inside the container.

Description

Technical Field

[0001] The present invention relates to a liquid crystal panel unit and a light irradiation device. Background Art

[0002] A light steering device that changes the direction of light using a plurality of polarization diffraction elements is described in Patent Document 1.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: U.S. Patent No. 8,982,313 Summary of the Invention

[0006] (I) Technical Problem to be Solved

[0007] In Patent Document 1, it is described that a liquid crystal panel constitutes a polarization diffraction element. However, if the liquid crystal panel becomes high temperature or low temperature, it may not be possible to achieve the desired function.

[0008] An object of the present invention is to maintain the liquid crystal panel at a specified temperature and suppress light loss caused by reflection of the liquid crystal panel.

[0009] (II) Technical Solution

[0010] One aspect of the present invention for achieving the above object is a liquid crystal panel unit including:

[0011] A liquid crystal panel;

[0012] A housing that houses the liquid crystal panel and has an entrance and an exit, the entrance allowing light from the outside to enter the liquid crystal panel, and the exit emitting the light from the liquid crystal panel to the outside; and

[0013] A light-transmissive liquid having a refractive index closer to the liquid crystal panel than air and impregnating the liquid crystal panel inside the housing.

[0014] In addition, the technical problems disclosed in the present application and the solutions thereto are clarified by the specific implementation part and the drawings of the specification.

[0015] (III) Advantageous Effects

[0016] According to the present invention, it is possible to maintain the liquid crystal panel at a specified temperature and suppress light loss caused by reflection of the liquid crystal panel. Brief Description of the Drawings

[0017] Figure 1 It is an explanatory diagram of the liquid crystal panel unit 20.

[0018] Figure 2A It is an explanatory diagram of the liquid crystal panel unit 20 of the first modified example.

[0019] Figure 2B It is an explanatory diagram of the liquid crystal panel unit 20 of the second modified example.

[0020] Figure 3 It is an explanatory diagram of the measurement system 1A.

[0021] Figure 4A It is an explanatory diagram of the light deflection device 20A (liquid crystal panel unit 20).

[0022] Figure 4B It is an explanatory diagram of the unit cell 21.

[0023] Figure 5 It is an explanatory diagram of the illumination system 1B.

[0024] Figure 6 It is an explanatory diagram of the light distribution device 20B (liquid crystal panel unit 20).

[0025] Figure 7 It is an explanatory diagram of another illumination system 1B.

[0026] Figure 8 It is an explanatory diagram of another light distribution device 20B' (liquid crystal panel unit 20). Detailed implementation manners

[0027] <Cross-reference to related applications>

[0028] This application claims priority based on Japanese Patent Application No. 2022-210750 filed on December 27, 2022, and incorporates its content by reference.

[0029] Hereinafter, the detailed implementation manners will be described with reference to the accompanying drawings. In addition, in the following description, the same or similar structures may be denoted by the same reference numerals and repeated descriptions may be omitted.

[0030] ===== Embodiment =====

[0031] <Liquid crystal panel unit>

[0032] Figure 1 It is an explanatory diagram of the liquid crystal panel unit 20.

[0033] In the following description, various directions are defined as shown in the figures. The Z direction is the direction perpendicular to the panel surface of the liquid crystal panel 22. In addition, the side of the light exit 34 as viewed from the light entrance 32 is sometimes referred to as "front", and the opposite side as "rear". The X direction and the Y direction are directions perpendicular to the Z direction. Here, the Y direction is the direction along the vertical direction. The X direction is the direction perpendicular to the Z direction and the Y direction, and here it is the direction perpendicular to the paper surface.

[0034] The liquid crystal panel unit 20 is a unit including the liquid crystal panel 22. The light incident on the liquid crystal panel unit 20 is emitted to the outside of the liquid crystal panel unit 20 through the liquid crystal panel 22. The liquid crystal panel unit 20 can, for example, constitute a light deflection device (described later) or a light distribution device 20B (such as an ADB device; described later). The liquid crystal panel unit 20 includes a liquid crystal panel 22, a housing 30, and a liquid 40.

[0035] The liquid crystal panel 22 is a plate-like component in which a liquid crystal layer is disposed between glass substrates. The liquid crystal panel 22 can be, for example, a diffraction element that diffracts light or a light-shielding element that shields a specified region. The liquid crystal panel 22 has a pair of glass substrates, a liquid crystal layer disposed between the glass substrates, and transparent electrodes. In addition, the liquid crystal panel 22 may include structures other than the glass substrates, the liquid crystal layer, and the transparent electrodes (such as a polarizing plate, etc.).

[0036] The liquid crystal panel unit 20 in the figure includes a plurality of liquid crystal panels 22. The plurality of liquid crystal panels 22 are stacked and disposed. The plurality of liquid crystal panels 22 are disposed along a direction perpendicular to the panel surface of the plate-like liquid crystal panel 22. However, the number of liquid crystal panels 22 included in the liquid crystal panel unit 20 may also be one.

[0037] The housing 30 is a component that houses the liquid crystal panel 22. The housing 30 is configured in a box shape or a cylindrical shape so as to have a housing space. The housing 30 is sometimes also referred to as an outer shell, a casing, or a lens barrel. The liquid crystal panel 22 is housed in the housing space inside the housing 30. The housing 30 in the figure houses a plurality of liquid crystal panels 22, but the number of liquid crystal panels 22 housed in the housing 30 may also be one. The housing 30 has a holding portion (not shown), and the liquid crystal panel 22 is held inside the housing 30 by the holding portion. The housing 30 is configured to allow light to pass through, and an entrance 32 and an exit 34 that are entrances and exits for light to pass through are provided in the housing 30. The liquid 40 that impregnates the liquid crystal panel 22 is housed inside the housing 30.

[0038] The housing 30 has an entrance port 32 and an exit port 34. The entrance port 32 is a part for allowing light from the outside (e.g., the light source 12) to enter the liquid crystal panel 22. The exit port 34 is a part for allowing light to be emitted from the inside of the housing 30 to the outside. Here, the exit port 34 emits the light from the liquid crystal panel 22 (the light passing through the liquid crystal panel 22) to the outside.

[0039] The entrance port 32 and the exit port 34 are made of light-transmissive components. The components forming the entrance port 32 and the exit port 34 have the function of sealing the liquid 40 inside the housing 30. Here, the entrance port 32 and the exit port 34 are made of glass plates. In addition, the components forming the entrance port 32 and the exit port 34 are not limited to glass plates and may also be formed of optical elements such as lenses and polarizing plates.

[0040] The liquid 40 is a light-transmissive liquid 40 (transparent liquid) that impregnates the liquid crystal panel 22 inside the housing 30. The liquid 40 is, for example, silicone oil. The liquid 40 can particularly transmit light of the wavelength emitted from the light source 12.

[0041] The liquid 40 has a larger heat capacity per unit volume than air (the amount of heat required to raise the temperature of a unit volume of the liquid 40 by one degree is larger than the amount of heat required to raise the temperature of a unit volume of air by one degree). Therefore, when the liquid crystal panel 22 inside the housing 30 is impregnated with the liquid 40, the liquid crystal panel 22 is less affected by the temperature outside the liquid crystal panel unit 20 compared to the case where the surroundings of the liquid crystal panel 22 are air, and it is easy to maintain the temperature of the liquid crystal panel 22 constant. In addition, if the liquid crystal panel 22 becomes high temperature (e.g., 60 °C or higher), the arrangement of liquid crystal molecules may become random, and if it becomes low temperature (e.g., -20 °C or lower), the orientation movement of liquid crystal molecules may become slow. Therefore, if it becomes high temperature or low temperature, the desired function may not be achieved. Therefore, it is particularly effective to impregnate the liquid crystal panel 22 with the liquid 40 and keep the liquid crystal panel 22 at a specified temperature.

[0042] The liquid 40 has the function of reducing the reflection loss at the liquid crystal panel 22. This will be described.

[0043] In this embodiment, since the liquid crystal panel 22 is immersed in the liquid 40, the surface of the liquid crystal panel 22 comes into contact with the liquid 40. Therefore, light enters and exits at the interface between the liquid crystal panel 22 and the liquid 40. Generally, when light enters and exits at the interface between two substances with different refractive indices, the smaller the difference in refractive indices of the two substances at the interface, the smaller the reflection loss. For example, the reflection loss at the interface between air (n = 1.0) and glass (n = 1.51) is approximately 4.1%. In contrast, the reflection loss at the interface between silicone oil (n = 1.39) and glass is approximately 0.17%. Therefore, in this embodiment, the liquid 40 in which the liquid crystal panel 22 is immersed is a substance whose refractive index is closer to the refractive index (n = 1.51) of the liquid crystal panel 22 (glass) than the refractive index of air (n = 1.0). Thereby, the reflection loss at the liquid crystal panel 22 can be reduced. In addition, when light enters and exits a plurality of liquid crystal panels 22 arranged in a stacked manner, the influence of the loss of light caused by multiple reflections (multiple reflection loss) is particularly large. However, in this embodiment, by immersing the liquid crystal panel 22 in the liquid 40 with a refractive index close to that of the liquid crystal panel 22 (glass), the influence of multiple reflection loss can be alleviated. Thus, when a plurality of liquid crystal panels 22 are arranged in a stacked manner in the housing 30, it is particularly effective to immerse the liquid crystal panels 22 in the liquid 40 with a refractive index close to that of the liquid crystal panel 22 (glass).

[0044] Preferably, the housing 30 is made of a heat-insulating material. A heat-insulating material is a component with a low thermal conductivity. By making the housing 30 of a heat-insulating material, the housing 30 functions as a thermostat, and it is easy to maintain the liquid 40 at a specified temperature. In addition, by making the housing 30 of a heat-insulating material, the liquid crystal panel 22 is not easily affected by the temperature outside the liquid crystal panel unit 20, and it is easy to maintain the liquid crystal panel 22 at a specified temperature. For example, the housing 30 is made of a resin with a low thermal conductivity. Thereby, compared with the case where the housing 30 is made of metal, the liquid crystal panel 22 is not easily affected by external heat.

[0045] Here, the housing 30 is made of a component (heat-insulating material) with a lower thermal conductivity than the components (glass) constituting the light incident port 32 and the light exit port 34. Thereby, the temperature outside the liquid crystal panel unit 20 is more difficult to transfer to the inside of the housing 30. In addition, in this case, it is preferable that the area of contact between the components (glass) constituting the light incident port 32 and the light exit port 34 and the liquid 40 is smaller than the area of contact between the housing 30 and the liquid 40. Thereby, heat transfer from the outside to the inside of the housing 30 via the light incident port 32 and the light exit port 34 can be suppressed. In addition, here, the housing 30 is made of a component (heat-insulating material) with a lower thermal conductivity than the liquid crystal panel 22 (glass). In addition, it is preferable that the housing 30 is made of a component (heat-insulating material) with a lower thermal conductivity than the liquid 40 (e.g., silicone oil). Thereby, the temperature outside the liquid crystal panel unit 20 is less likely to transfer to the inside of the housing 30.

[0046] The control unit 60 in the figure controls the liquid crystal panel 22. The control unit 60 has an arithmetic device and a storage device (not shown). The arithmetic device is, for example, an arithmetic processing device composed of a CPU, GPU, MPU, ASIC, etc. A part of the arithmetic device may also be composed of an analog arithmetic circuit. The storage device is composed of a main storage device and an auxiliary storage device, and is a device for storing programs and data. The liquid crystal panel 22 is controlled by the arithmetic device executing the program stored in the storage device. The control unit 60 is composed of, for example, an ECU (Electronic Control Unit) that controls a vehicle.

[0047] The control unit 60 has a driving unit 61 for driving the liquid crystal panel 22. The driving unit 61 (and the control unit 60) is arranged outside the housing 30. By arranging the driving unit 61 outside the housing 30, heat generation inside the housing 30 can be further suppressed. In addition, it is preferable that a connector (not shown) for inputting a signal to the driving unit 61 is provided in the housing 30.

[0048] Figure 2A It is an explanatory diagram of the liquid crystal panel unit 20 of the first modification example. Figure 2B It is an explanatory diagram of the liquid crystal panel unit 20 of the second modification example.

[0049] The housing 30 of the liquid crystal panel unit 20 of the first modification example and the second modification example has a temperature control unit 36. The temperature control unit 36 controls the temperature of the liquid 40. Here, the temperature control unit 36 has a temperature control element 361 and a heat conducting plate 362.

[0050] The temperature control element 361 is an element that performs at least one of cooling and heating. Here, the temperature control unit 36 has a Peltier element as the temperature control element 361. The Peltier element is an element that can perform both cooling and heating. One surface of the plate-shaped Peltier element becomes a cooling surface (heat absorption surface), and the other surface becomes a heating surface, and the cooling surface and the heating surface can be switched according to the direction of the current. The temperature control element 361 is not limited to an element having a Peltier element. For example, the temperature control element 361 may also be composed of a cooling element (cooler) or a heating element (heater). However, since the temperature control unit 36 becomes a structure capable of performing both cooling and heating of the liquid 40 by having a Peltier element, it is preferable that the temperature control element 361 is a Peltier element. When the temperature control unit 36 has a Peltier element, it is preferable that there is no wall surface (heat insulating material) of the housing 30 at the position where the temperature control unit 36 is arranged. Thus, it is easier to generate a temperature difference between the cooling surface and the heating surface of the Peltier element, and the Peltier element can be used to efficiently control the temperature of the liquid 40.

[0051] The heat conduction plate 362 is a component for transferring heat between the temperature control element 361 and the liquid 40. The heat conduction plate 362 is composed of a component with high thermal conductivity, for example, it is composed of a copper plate. The heat conduction plate 362 is arranged on the inner surface (the surface on the liquid 40 side) of the temperature control element 361. In the figure, the contact area between the heat conduction plate 362 and the liquid 40 is depicted to be the same as the contact area between the heat conduction plate 362 and the temperature control element 361, but the heat conduction plate 362 can also be configured such that the contact area between the heat conduction plate 362 and the liquid 40 is larger than the contact area between the heat conduction plate 362 and the temperature control element 361. Thereby, the heat of the temperature control element 361 can be efficiently transferred to the liquid 40. In addition, the temperature control section 36 may not have the heat conduction plate 362 (the temperature control section 36 can also be configured such that the temperature control element 361 is in direct contact with the liquid 40).

[0052] As Figure 2B shown in the second modification example of

[0053] the accommodating body 30 may also have two temperature control sections 36 (the first temperature control section 36A and the second temperature control section 36B). In this case, the first temperature control section 36A and the second temperature control section 36B can also be controlled to different temperatures. By having the temperature of the first temperature control section 36A different from the temperature of the second temperature control section 36B, a temperature difference can be generated in the liquid 40 inside the accommodating body 30, promoting the convection of the liquid 40 and making it easier to adjust the temperature of the liquid crystal panel 22.

[0054] As Figure 1 、 Figure 2A and Figure 2BAs shown, the liquid crystal panel unit 20 of the present embodiment includes: a liquid crystal panel 22; a housing 30 that houses the liquid crystal panel 22 and has an incident port 32 and an exit port 34; and a light-transmissive liquid 40 that immerses the liquid crystal panel 22 inside the housing 30. Thereby, the liquid crystal panel 22 can be maintained at a prescribed temperature. In addition, by immersing the liquid crystal panel 22 in the liquid 40 whose refractive index is closer to that of the liquid crystal panel 22 than air, the reflection loss at the liquid crystal panel 22 can be reduced.

[0055] In addition, as described above, it is preferable that the housing 30 houses a plurality of liquid crystal panels 22 in a state where the plurality of liquid crystal panels 22 arranged in layers are immersed in the liquid 40. Thereby, the multiple reflection loss can be suppressed.

[0056] <Example of Use of Liquid Crystal Panel Unit 20: Light Deflection Device>

[0057] Figure 3 It is an explanatory diagram of the measurement system 1A.

[0058] The measurement system 1A is a device for measuring distance. The measurement system 1A is a device having a function of so-called LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging). The measurement system 1A measures the distance to an object in a TOF (Time of Flight) manner by irradiating measurement light toward a measurement area and detecting the reflected light reflected from the surface of the object located in the measurement area. In addition, the measurement system 1A is not limited to the TOF method, and for example, the distance can also be measured in an FMCW (Frequency Modulated Continuous Wave) method. The measurement system 1A includes a light irradiation device 10, a light reception device 50A, and a control unit 60.

[0059] The light irradiation device 10 is a device that irradiates light. The light irradiation device 10 can change the position of the irradiated light. Figure 3 The light irradiation device 10 shown can move the position of the light spot that irradiates the measurement light. In addition, the light irradiation device 10 can scan and move the light spot that irradiates the measurement light, or can jump and move the light spot that irradiates the measurement light.

[0060] The light irradiation device 10 includes a light source 12 and a light deflection device 20A. The light source 12 is a device that emits light. Here, the light source 12 is a laser light emitting device that emits laser light. The light deflection device 20A is a device that changes the direction of light. The light emitted from the light source 12 is incident on the light deflection device 20A, and the direction is changed by the light deflection device 20A and irradiated toward the measurement area. The light deflection device 20A is composed of a liquid crystal panel unit 20 (therefore, the light irradiation device 10 includes the light source 12, the liquid crystal panel 22, the housing 30, and the liquid 40). The liquid crystal panel unit 20 that constitutes the light deflection device 20A will be described later.

[0061] The light receiving device 50A is a device that receives reflected light. The light receiving device 50A includes an optical system 51A for light reception and a light receiving sensor 52A. The optical system 51A for light reception is an optical system for causing the light receiving unit to receive the reflected light coming from the measurement area. The light receiving sensor 52A is an element (photoelectric conversion element) that converts the received reflected light (light signal) into an electrical signal. The light receiving sensor 52A may be composed of an image sensor in which pixels are arranged in the XY directions, may be composed of a line sensor in which pixels are arranged in one direction (X direction or Y direction), or may be composed of one pixel. The light receiving sensor 52A outputs the light reception result as a light reception signal to the control unit 60.

[0062] The control unit 60 is responsible for the control of the measurement system 1A. The control unit 60 controls the light irradiation device 10. For example, the control unit 60 controls the emission of light from the light source 12 and controls the direction of the measurement light emitted from the light deflection device 20A. In addition, the control unit 60 has a drive unit 61 that drives the liquid crystal panel 22 of the light deflection device 20A, and controls the direction of the measurement light emitted from the light deflection device 20A by controlling the liquid crystal panel 22. Further, the control unit 60 measures the distance to the object based on the output signal of the light receiving sensor 52A. The control unit 60 executes the programs stored in the storage device through an arithmetic device, and thus performs various processes for measuring the distance to the object. For example, the control unit 60 calculates the flight time of the measurement light based on the time when the light is emitted from the light source 12 and the time when the light is received by the light receiving sensor 52A, calculates the distance (Z coordinate) to the reflection point based on the flight time of the measurement light, and calculates the three-dimensional coordinates (X coordinate, Y coordinate, and Z coordinate) of the reflection point based on the direction of the light emitted from the light deflection device 20A. In addition, the control unit 60 changes the direction of the measurement light based on the light deflection device 20A, obtains the three-dimensional coordinates of a plurality of reflection points in the measurement area, and thereby obtains so-called point cloud data.

[0063] Figure 4A It is an explanatory diagram of the light deflection device 20A (liquid crystal panel unit 20).

[0064] The optical deflection device 20A is composed of the aforementioned liquid crystal panel unit 20, and includes a plurality of liquid crystal panels 22A, a housing 30, and a liquid 40. The plurality of liquid crystal panels 22A of the optical deflection device 20A include liquid crystal panels (221A, 222A, 223A) that control the direction of incident light, as described below. Here, the optical deflection device 20A has a unit cell 21 composed of a liquid crystal panel 22.

[0065] Figure 4B It is an explanatory diagram of the unit cell 21.

[0066] The unit cell 21 is composed of a liquid crystal panel 22 and is a unit that changes the direction of light (a unit that controls the direction of incident light). The deflection angle of light based on one unit cell 21 is small, but the deflection angle of light can be increased by arranging a plurality of unit cells 21. For example, by arranging 16 sets of unit cells 21 capable of changing the direction of light in the range of ±0.625° (1.25°), the direction of light can be changed in the range of 20°. In addition, the number of unit cells 21 included in the optical deflection device 20A is not limited to 16. Further, if the change angle of light can also be small, the number of unit cells 21 included in the optical deflection device 20A can also be 1.

[0067] The unit cell 21 in the figure is composed of two liquid crystal panels 22A (221A, 222A). Here, the unit cell 21 has a liquid crystal retarder 221A and a liquid crystal grating 222A.

[0068] The liquid crystal retarder 221A is a liquid crystal panel that controls the phase difference by changing the applied voltage. The liquid crystal retarder 221A has the function of a variable λ / 2 retardation plate. Here, if circularly polarized light is incident on the liquid crystal retarder 221A to which a voltage is applied, circularly polarized light with the reversed rotation direction is emitted from the liquid crystal retarder 221A. For example, when the incident light is left circularly polarized light (right circularly polarized light), when a voltage is applied to the liquid crystal retarder 221A, right circularly polarized light (left circularly polarized light) is emitted from the liquid crystal retarder 221A, and when no voltage is applied to the liquid crystal retarder 221A, left circularly polarized light (right circularly polarized light) is emitted from the liquid crystal retarder 221A.

[0069] The liquid crystal grating 222A is a liquid crystal panel that controls diffraction by changing the applied voltage. The liquid crystal grating 222A has the function of a variable polarization diffraction grating. Here, if circularly polarized light is incident on the liquid crystal grating 222A to which a voltage is applied, the light diffracts in the direction corresponding to the rotation direction. For example, when a voltage is applied to the liquid crystal grating 222A, the incident left circularly polarized light (right circularly polarized light) emits light in the direction of +1 order (-1 order), and when no voltage is applied to the liquid crystal grating 222A, the light passes through without diffraction.

[0070] The liquid crystal panel 22A (here, the liquid crystal retarder 221A and the liquid crystal grating 222A) constituting the unit cell 21 is a liquid crystal panel for changing the direction of incident light stepwise. For example, when the unit cell 21 is in air, the unit cell 21 can change the direction of the emitted light stepwise at angles of +0.625°, 0°, and -0.625° with respect to the angle of the incident light. The control unit 60 controls the voltage of the liquid crystal retarder 221A and the liquid crystal grating 222A to control the direction of the emitted light with respect to the incident light.

[0071] In addition, in the present embodiment, the liquid crystal panel 22A constituting the unit cell 21 is immersed in a liquid 40 whose refractive index is closer to the liquid crystal panel 22A (glass; n = 1.51) than air (n = 1.0). Therefore, inside the liquid 40, the changeable angle (deflection angle) of the emitted light (the light emitted from the unit cell 21) with respect to the incident light (the light incident on the unit cell 21) becomes smaller than when in air. For example, the deflection angle becomes an angle smaller than ±0.625°. However, since the deflected light inside the housing 30 is emitted from the light exit 34 of the liquid crystal panel unit 20 to the outside (air), if we focus on the emitted light emitted from the light exit 34, the unit cell 21 immersed in the liquid 40 can change the direction of the emitted light with respect to the incident light by the same angle (e.g., ±0.625°) as in the case of being in air.

[0072] Furthermore, when liquid crystal panels 22 that change the direction of light are stacked, the angle of the incident light is likely to be larger for the liquid crystal panel 22 arranged on the front side. Therefore, when the liquid crystal panel has an angle dependence, if liquid crystal panels 22 that change the direction of light are stacked, the performance of the liquid crystal panel 22 arranged on the front side may be affected by the incident angle of light. In contrast, in the present embodiment, since the liquid crystal panel 22 is immersed in the liquid 40, inside the housing 30, the angle of the light emitted from the unit cell 21 becomes smaller. As a result, the angle of the light incident on the liquid crystal panel 22 arranged on the front side can be reduced. Therefore, the following effect can be obtained: Even when the liquid crystal panel 22A has an angle dependence (the case where the performance of the liquid crystal panel 22A is affected by the incident angle of light), by immersing the liquid crystal panel 22A in the liquid 40, the influence of the angle dependence can be reduced. Thus, when liquid crystal panels 22 that change the direction of light and have an angle dependence are stacked, the structure in which the liquid crystal panel 22 is immersed in the liquid 40 is particularly effective.

[0073] As described above, the unit cell 21 is composed of two liquid crystal panels 22A (the liquid crystal retarder 221A and the liquid crystal grating 222A). However, the number of liquid crystal panels 22A constituting the unit cell 21 can also be one, or more than two.

[0074] The optical deflection device 20A may include not only a liquid crystal panel (the liquid crystal retarder 221A and the liquid crystal grating 222A that constitute the unit cell 21; equivalent to the first liquid crystal panel) for stepwise changing the direction of light, but also a liquid crystal panel (the second liquid crystal panel) for continuously changing the direction of light. In addition, when the optical deflection device 20A is composed of only a plurality of unit cells 21, the directions of the emitted light are discrete (for example, the emission directions of the light are discrete at intervals of 0.625°). In contrast, by further providing a liquid crystal panel (the second liquid crystal panel) for continuously changing the direction of light, light can be continuously emitted over a large range. For example, when the number of unit cells 21 is set to N, light can be continuously scanned within a range of 1.25°×N. Here, among the plurality of liquid crystal panels 22A arranged along the Z direction, the liquid crystal panel 22A closest to the light exit 34 is a continuous steering liquid crystal panel 223A capable of continuously changing the direction of light within a range of ±0.625° or more. In addition, it is preferable that the range of the angle of light that the continuous steering liquid crystal panel 223A can change is larger than the angle of light that one unit cell 21 can stepwise change (the deflection angle; here, 0.625°). In addition, it is preferable that the range of the angle of light that the continuous steering liquid crystal panel 223A can change is less than twice the deflection angle of one unit cell 21. In this way, even if the deflection angle of the second liquid crystal panel (the continuous steering liquid crystal panel 223A) is small, by combining the second liquid crystal panel with a plurality of first liquid crystal panels (a plurality of unit cells 21), light can be continuously scanned within a large range (for example, 20°).

[0075] In order to change the direction of light within a range of 20°, 16 sets (=20 / 1.25) of unit cells 21 are required. When there are 66 interfaces between silicone oil and glass due to laminating and arranging 16 sets of unit cells 21 and the continuous steering liquid crystal panel 223A, since the reflection loss at the interface between silicone oil (n = 1.39) and glass is about 0.17%, the emitted light becomes about 89.3% of the incident light (the 66th power of 0.9983%). In addition, when the liquid crystal panel 22A is arranged in air without being immersed in the liquid 40, the reflection loss at the interface between air (n = 1.0) and glass (n = 1.51) is about 4.1%, so the emitted light becomes about 6.31% of the incident light (the 66th power of 0.959%). In this way, in the situation where a plurality of liquid crystal panels 22 are accommodated in the housing 30, by immersing the liquid crystal panel 22 in the liquid 40 with a refractive index close to that of the liquid crystal panel 22 (glass), the influence of multiple reflection losses can be reduced, and the intensity of the emitted light relative to the incident light can be significantly increased.

[0076] As described above, Figure 3The light irradiation device 10 shown includes: a light source 12; a liquid crystal panel 22; a housing 30 that houses the liquid crystal panel 22 and has an incident port 32 and an exit port 34; and a light-transmissive liquid 40 that immerses the liquid crystal panel 22 inside the housing 30. Thereby, the liquid crystal panel 22 can be maintained at a specified temperature. In addition, by immersing the liquid crystal panel 22 in the liquid 40 whose refractive index is closer to that of the liquid crystal panel 22 than air, the reflection loss at the liquid crystal panel 22 can be reduced.

[0077] In addition, as shown in FIG. 4, it is preferable that the housing 30 houses a plurality of liquid crystal panels 22 in a state where the stacked and arranged liquid crystal panels 22 are immersed in the liquid 40. Thereby, the multiple reflection loss can be suppressed.

[0078] <Example of Use 2 of Liquid Crystal Panel Unit 20: Light Distribution Device>

[0079] Figure 5 It is an explanatory diagram of the lighting system 1B.

[0080] The lighting system 1B in the figure is a device that controls light distribution and performs lighting. For example, the lighting system 1B is a light distribution variable headlamp system having an ADB (Adaptive Driving Beam) function, and controls the light irradiation area according to the position of a vehicle ahead (for example, an oncoming vehicle, a vehicle traveling ahead). The lighting system 1B includes a light irradiation device 10, a camera 50B, and a control unit 60.

[0081] The light irradiation device 10 can change the position of the irradiated light. Figure 5 The shown light irradiation device 10 can change the light irradiation area. The light irradiation device 10 includes a light source 12, a light distribution device 20B, and a projection lens 24B.

[0082] The light source 12 is a device that emits light. Here, the light source 12 is composed of an LED (light-emitting diode). The light source 12 may be composed of one LED chip, or may be an LED array having a plurality of LED chips. In addition, the light source 12 may not be an LED. For example, it may be an HID (high-intensity discharge lamp). Thus, the light emitted from the light source 12 of the light irradiation device 10 is not limited to laser light. The light emitted from the light source 12 is reflected by a reflector (reflector 14) and enters the incident port 32 of the light distribution device 20B. In addition, the light emitted from the light source 12 is irradiated forward via the light distribution device 20B.

[0083] The light distribution device 20B is a device that controls the light irradiation area (in other words, the light distribution pattern). Here, the light distribution device 20B controls the light distribution pattern by blocking a part of the incident light. For example, the light distribution device 20B generates the following light distribution pattern: blocking the light irradiated to the area of the vehicle ahead and irradiating light to other areas. In addition, blocking the light also includes reducing the light intensity. The light distribution device 20B is composed of the liquid crystal panel unit 20 (therefore, the light irradiation device 10 includes the light source 12, the liquid crystal panel 22, the housing 30, and the liquid 40). The liquid crystal panel unit 20 constituting the light distribution device 20B will be described later.

[0084] The projection lens 24B is a lens that projects the light emitted from the light distribution device 20B forward.

[0085] The camera 50B is a device (imaging device) that captures the front. In addition, the camera 50B includes an optical system for light reception and a light reception sensor (image sensor) not shown. The camera 50B outputs the data of the captured image (image data) to the control unit 60.

[0086] The control unit 60 is responsible for controlling the lighting system 1B. For example, the control unit 60 controls the light distribution device 20B in the following manner: calculating the position of the vehicle ahead based on the image data obtained from the camera 50B, and blocking the light irradiated to the vehicle ahead based on the calculated position of the vehicle ahead.

[0087] Figure 6 It is an explanatory diagram of the light distribution device 20B (liquid crystal panel unit 20). In addition, for reference, the control unit 60 that controls the light distribution device 20B is also depicted in the figure.

[0088] The light distribution device 20B is composed of the aforementioned liquid crystal panel unit 20. Therefore, the light distribution device 20B has the liquid crystal panel 22, the housing 30, and the liquid 40. The light distribution device 20B has the light-shielding liquid crystal panel 22B as the liquid crystal panel 22.

[0089] The light-shielding liquid crystal panel 22B is a liquid crystal panel that controls the light-blocking area. The light-shielding liquid crystal panel 22B has the function of a shutter. In addition, reducing the light intensity is also included in the meaning of "blocking the light". The area other than the light-blocking area of the light-shielding liquid crystal panel 22B becomes the transmission area through which the incident light passes. The light-shielding liquid crystal panel 22B can change the light-blocking area. The light-shielding liquid crystal panel 22B blocks the area corresponding to the signal of the control unit 60 (drive unit 61). The light-shielding liquid crystal panel 22B is disposed in the focal plane of the projection lens 24B. In addition, the focal plane of the projection lens 24B is set considering the refractive index of the liquid 40, the refractive index of the glass constituting the incident port 32 and the exit port 34, etc., and the light-shielding liquid crystal panel 22B is disposed in the focal plane of the projection lens 24B set considering the refractive index of the liquid 40, etc.

[0090] A polarizing plate 23 is disposed in front of and behind the liquid crystal panel 22B for light shielding. Here, the polarizing plate 23 is accommodated in the housing 30. In this way, the liquid crystal panel unit 20 can also stack and arrange plate-like components other than the liquid crystal panel 22 together with the liquid crystal panel 22 and accommodate them in the housing 30. In addition, the light distribution device 20B can also stack and arrange the light shielding liquid crystal panel 22B together with other liquid crystal panels 22 (for example, the liquid crystal lens 22C described later) and accommodate them in the housing 30.

[0091] Figure 7 It is an explanatory diagram of another lighting system 1B'.

[0092] In the figure, the lighting system 1B' is a position-variable spotlight system that can vary the position of the spotlight. For example, the lighting system 1B' controls the light irradiation area according to the position of pedestrians. The lighting system 1B' includes a light irradiation device 10, a camera 50B, and a control unit 60. Since Figure 7 the camera 50B and the control unit 60 of the shown lighting system 1B' are substantially the same as those of Figure 5 the lighting system 1B shown, the description thereof is omitted here.

[0093] The light irradiation device 10 includes a light source 12 and a light distribution device 20B'. Since the light source 12 is substantially the same as that of Figure 5 the lighting system 1B shown, the description thereof is omitted here.

[0094] Figure 8 It is an explanatory diagram of another light distribution device 20B' (liquid crystal panel unit 20). The light distribution device 20B' in the figure is composed of the aforementioned liquid crystal panel unit 20, and includes a plurality of liquid crystal panels 22, a housing 30, and a liquid 40 (therefore, the light irradiation device 10 includes a light source 12, a liquid crystal panel 22, a housing 30, and a liquid 40). The light distribution device 20B' includes a plurality of liquid crystal lenses 22C (liquid crystal lens group) as the plurality of liquid crystal panels 22.

[0095] The liquid crystal lens 22C is a liquid crystal panel that functions as a lens. The liquid crystal lens 22C is configured to have variable optical characteristics by controlling the applied voltage. Here, the liquid crystal lens 22C can change the center position of the lens (the position of the rotation symmetry axis of the refractive index distribution in the plane of the liquid crystal panel) within the plane of the liquid crystal panel. By changing the lens center position of the liquid crystal lens 22C with respect to the incident light, the position of the spotlight can be shifted in the XY direction with respect to the center of the light beam of the incident light (refer to the dash-dot line in the figure). In addition, the liquid crystal lens 22C can also be configured to have a variable focal length.

[0096] As described above, Figure 5 and Figure 7The light irradiation device 10 shown includes: a light source 12; a liquid crystal panel 22; a housing 30 that houses the liquid crystal panel 22 and has an incident port 32 and an exit port 34; and a light-transmissive liquid 40 that immerses the liquid crystal panel 22 inside the housing 30. Thereby, the liquid crystal panel 22 can be maintained at a specified temperature. In addition, by immersing the liquid crystal panel 22 in the liquid 40 whose refractive index is closer to that of the liquid crystal panel 22 than air, the reflection loss at the liquid crystal panel 22 can be reduced.

[0097] In addition, as Figure 6 shown, the housing 30 can house one liquid crystal panel 22 in a state where one liquid crystal panel 22 is immersed in the liquid 40. On the other hand, as Figure 8 shown, the housing 30 can also house a plurality of liquid crystal panels 22 arranged in layers in a state where the plurality of liquid crystal panels 22 are immersed in the liquid 40. In either case, the reflection loss at the liquid crystal panel 22 can be reduced.

[0098] As described above, the embodiments of the present invention have been described in detail, but the present invention is not limited to the above embodiments and includes various modification examples. In addition, the above embodiments have described the structure in detail for easy understanding of the present invention, and it is not necessarily limited to having all the structures described. In addition, for a part of the structure of the above embodiments, addition, deletion, and replacement can be made in other structures.

[0099] Explanation of reference numerals:

[0100] 1A: measurement system; 1B, 1B’: illumination system; 10: light irradiation device; 12: light source; 14: reflector; 20: liquid crystal panel unit; 20A: light deflection device; 20B, 20B’: light distribution device; 21: unit cell; 22: liquid crystal panel; 22A: liquid crystal panel; 221A: liquid crystal retarder; 222A: liquid crystal grating; 223A: continuously deflecting liquid crystal panel; 22B: light shielding liquid crystal panel; 22C: liquid crystal lens; 23: polarizing plate; 24B: projection lens; 30: housing; 32: incident port; 34: exit port; 36: temperature control unit; 36A: first temperature control unit; 36B: second temperature control unit; 361: temperature control element; 362: heat conducting plate; 40: liquid; 50A: light receiving device; 50B: camera; 51A: light receiving optical system; 52A: light receiving sensor; 60: control unit; 61: driving unit.

Claims

1. A liquid crystal panel unit, comprising: A liquid crystal panel; A housing that houses the liquid crystal panel and has an incident port and an exit port, the incident port allowing light from the outside to enter the liquid crystal panel, and the exit port emitting the light from the liquid crystal panel to the outside; and A light-transmissive liquid having a refractive index closer to that of the liquid crystal panel than air and impregnating the liquid crystal panel inside the housing.

2. The liquid crystal panel unit according to claim 1, wherein The housing houses a plurality of the liquid crystal panels in a state where the plurality of liquid crystal panels arranged in a stacked manner are impregnated in the liquid.

3. The liquid crystal panel unit according to claim 1 or 2, wherein A liquid crystal panel for controlling the direction of incident light is housed in the housing.

4. The liquid crystal panel unit according to claim 3, wherein A plurality of first liquid crystal panels for stepwise changing the direction of light and a second liquid crystal panel for continuously changing the direction of light are housed in the housing.

5. The liquid crystal panel unit according to any one of claims 1 to 4, wherein A liquid crystal panel for controlling a light-shielded area is housed in the housing.

6. The liquid crystal panel unit according to any one of claims 1 to 5, wherein The housing is made of a heat-insulating material.

7. The liquid crystal panel unit according to any one of claims 1 to 6, wherein The housing has a temperature control section for controlling the temperature of the liquid.

8. The liquid crystal panel unit according to claim 7, wherein The housing has a first temperature control section and a second temperature control section for controlling the temperature of the liquid, The first temperature control section and the second temperature control section are controlled to different temperatures.

9. The liquid crystal panel unit according to claim 8, wherein The first temperature control section is disposed above the second temperature control section and is controlled to a lower temperature than the second temperature control section.

10. A light irradiation device, comprising: A light source that emits light; A liquid crystal panel; A housing that houses the liquid crystal panel and has an incident port and an exit port, the incident port allowing light from the light source to enter the liquid crystal panel, and the exit port emitting the light from the liquid crystal panel to the outside; and A light-transmissive liquid having a refractive index closer to that of the liquid crystal panel than air and impregnating the liquid crystal panel inside the housing.

Images