Lighting device

Abstract

The lighting device includes a light source, an optical element, and a control device that controls the optical element. The control device includes: a signal generation circuit unit; a switching circuit section including first to fourth output channels electrically connected to the first to fourth transparent electrodes of the liquid crystal cell of the optical element, respectively; and a first signal line and a second voltage signal line which are connected to the signal generation circuit unit and the switching circuit unit and through which the voltage signal generated by the signal circuit unit is transmitted, the switching circuit unit being driven so that the first voltage signal line is electrically connected to the first output channel during a first sub-frame period of the one-frame period, and the second voltage signal line being electrically connected to the second output channel during a second sub-frame period of the one-frame period. In a first sub-frame period of the one-frame period, the switching circuit unit is driven so that the first voltage signal line and the third output channel are conducted and the second signal line and the fourth output channel are conducted, and in a second sub-frame period of the one-frame period, the switching circuit unit is driven so that the first voltage signal line and the third output channel are conducted and the second signal line and the fourth output channel are conducted.

Description

Technical Field

[0001] One embodiment of the present invention relates to a lighting device that controls the light distribution of light emitted from a light source using liquid crystal. Background Art

[0002] Conventionally, an optical element that uses a change in the refractive index of liquid crystal by adjusting a voltage applied to liquid crystal, namely a so-called liquid crystal lens, is known. In addition, development of a lighting device using a light source and a liquid crystal lens is in progress (for example, see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-117344 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] The optical element of the lighting device is provided with a control circuit for controlling light distribution, and the control circuit includes a digital analog conversion circuit (DAC) and an amplifier circuit (AMP) which occupy a large area. In the conventional optical element, a voltage signal is generated for each transparent electrode which applies a voltage to a liquid crystal, and in the case of an optical element with a large number of transparent electrodes, the number of DACs and AMPs increases. However, when the number of DACs and AMPs which occupy a large area increases, the control circuit becomes larger and the manufacturing cost increases. Therefore, it is desired to reduce the number of DACs and AMPs included in the control circuit and reduce the manufacturing cost.

[0008] In view of the above problems, one object of one embodiment of the present invention is to provide a lighting device with reduced manufacturing costs.

[0009] Solutions for solving technical problems

[0010] An illumination device according to one embodiment of the present invention comprises: a light source; an optical element comprising a first liquid crystal unit and a second liquid crystal unit, wherein the first liquid crystal unit and the second liquid crystal unit diffuse and variably transmit light emitted from the light source; and a control device connected to the optical element and controlling the optical element, wherein the first liquid crystal unit and the second liquid crystal unit respectively comprise: a first substrate, on which a first transparent electrode and a second transparent electrode extending in a first direction are alternately provided; a second substrate, on which a third transparent electrode and a fourth transparent electrode extending in a second direction are alternately provided, wherein the second direction intersects the first direction; and a liquid crystal layer between the first substrate and the second substrate, wherein the control device comprises: a switch circuit unit, comprising a first output channel, a second output channel, a third output channel, and a fourth output channel, wherein the first output channel is electrically connected to the first transparent electrode of the first liquid crystal unit, the second output channel is electrically connected to the second transparent electrode of the first liquid crystal unit, and the third output channel is electrically connected to the fourth transparent electrode of the first liquid crystal unit. The output channel is electrically connected to the third transparent electrode of the first liquid crystal unit, and the fourth output channel is electrically connected to the fourth transparent electrode of the first liquid crystal unit; the signal generating circuit unit generates a plurality of voltage signals, and the plurality of voltage signals are input to the first transparent electrode, the second transparent electrode, the third transparent electrode, and the fourth transparent electrode of the first liquid crystal unit and the second liquid crystal unit, respectively; and the first voltage signal and the second voltage signal are connected to the switch circuit unit and the signal generating circuit unit, and are respectively transmitted for one of the generated plurality of voltage signals, and one frame period includes a first sub-frame period and a second sub-frame period, during the first sub-frame period, the switch circuit unit drives to connect the first voltage signal line to the first output channel, and connect the second voltage signal line to the second output channel, and during the second sub-frame period, the switch circuit unit drives to connect the first voltage signal line to the third output signal, and connect the second voltage signal line to the fourth output channel.

[0011] An illumination device according to one embodiment of the present invention includes: a light source; an optical element including a first liquid crystal unit and a second liquid crystal unit, wherein the first liquid crystal unit and the second liquid crystal unit diffuse and variably transmit light emitted from the light source; and a control device connected to the optical element and controlling the optical element, wherein the first liquid crystal unit and the second liquid crystal unit respectively include: a first substrate, on which a first transparent electrode and a second transparent electrode extending in a first direction are alternately provided; a second substrate, on which a third transparent electrode and a fourth transparent electrode extending in a second direction are alternately provided, wherein the second direction intersects the first direction; and a liquid crystal layer between the first substrate and the second substrate, wherein the control device includes: a switch circuit unit, including a first output channel, a second output channel, a third output channel, a fourth output channel, a fifth output channel, a sixth output channel, a seventh output channel, and an eighth output channel, wherein the first output channel is electrically connected to the first transparent electrode of the first liquid crystal unit, the second output channel is electrically connected to the second transparent electrode of the first liquid crystal unit, the third output channel is electrically connected to the third transparent electrode of the first liquid crystal unit, the fourth output channel is electrically connected to the fourth transparent electrode of the first liquid crystal unit, the fifth output channel is electrically connected to the first transparent electrode of the second liquid crystal unit, and the sixth output channel is electrically connected to the The switch circuit unit is electrically connected to the second transparent electrode of the second liquid crystal unit, the seventh output channel is electrically connected to the third transparent electrode of the second liquid crystal unit, and the eighth output channel is electrically connected to the fourth transparent electrode of the second liquid crystal unit; a signal generation circuit unit generates a plurality of voltage signals, and the plurality of voltage signals are input to the first transparent electrode, the second transparent electrode, the third transparent electrode, and the fourth transparent electrode of the first liquid crystal unit and the second liquid crystal unit, respectively; and a first voltage signal line, a second voltage signal line, a third voltage signal line, and a fourth voltage signal line are connected to the switch circuit unit and the signal generation circuit unit, and are respectively used to transmit one of the generated plurality of voltage signals, one frame period includes a first sub-frame period and a second sub-frame period, during the first sub-frame period, the switch circuit unit drives to make the first voltage signal line, the second voltage signal line, the third voltage signal line, and the fourth voltage signal line respectively connected to the first output channel, the second output channel, the third output channel, and the fourth output channel, and during the second sub-frame period, the switch circuit unit drives to make the first voltage signal line, the second voltage signal line, the third voltage signal line, and the fourth voltage signal line respectively connected to the fifth output channel, the sixth output channel, the seventh output channel, and the eighth output channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram showing the structure of a lighting device according to an embodiment of the present invention.

[0013] Figure 2 This is a block diagram showing the structure of a lighting device according to an embodiment of the present invention.

[0014] Figure 3A This is a schematic cross-sectional view showing the structure of a lighting device according to an embodiment of the present invention.

[0015] Figure 3B This is a schematic cross-sectional view showing the structure of a lighting device according to an embodiment of the present invention.

[0016] Figure 4A This is a schematic plan view showing an electrode pattern of a liquid crystal cell included in an optical element of a lighting device according to an embodiment of the present invention.

[0017] Figure 4B This is a schematic plan view showing an electrode pattern of a liquid crystal cell included in an optical element of a lighting device according to an embodiment of the present invention.

[0018] Figure 5A It is a schematic diagram for explaining the optical characteristics of the liquid crystal cell included in the optical element of the lighting device according to one embodiment of the present invention.

[0019] Figure 5B It is a schematic diagram for explaining the optical characteristics of the liquid crystal cell included in the optical element of the lighting device according to one embodiment of the present invention.

[0020] Fig. 6A This is a timing chart showing voltage signals input to transparent electrodes of a liquid crystal cell for controlling light distribution in the lighting device according to one embodiment of the present invention.

[0021] Figure 6B This is a timing chart showing voltage signals input to transparent electrodes of a liquid crystal cell for controlling light distribution in the lighting device according to one embodiment of the present invention.

[0022] Figure 6C This is a timing chart showing voltage signals input to transparent electrodes of a liquid crystal cell for controlling light distribution in the lighting device according to one embodiment of the present invention.

[0023] Figure 7 This is a block diagram showing the structure of a lighting device according to an embodiment of the present invention.

[0024] Figure 8 This is a timing chart showing voltage signals input to transparent electrodes of a liquid crystal cell for controlling light distribution in the lighting device according to one embodiment of the present invention.

[0025] Fig. 9 This is a block diagram showing the structure of a lighting device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] Hereinafter, each embodiment of the present invention will be described with reference to the drawings, etc. However, the present invention can be implemented in various forms within the scope of the technical concept and is not to be interpreted as being limited to the description of the following exemplary embodiments.

[0027] In the drawings, in order to make the description clearer, the width, thickness, shape, etc. of each part are sometimes schematically shown in comparison with the actual situation, but it is only an example after all, and the shape of the figure itself does not limit the interpretation of the present invention. In addition, in the drawings, elements having the same function as the elements described in the drawings that have already appeared in the specification are sometimes marked with the same reference numerals even in separate drawings to omit repeated descriptions.

[0028] When a certain film is processed to form a plurality of structures, each structure may have different functions and effects, and each structure may have different bases. However, these multiple structures are derived from films formed into the same layer in the same process and have the same material. Therefore, these multiple films are defined as films existing in the same layer.

[0029] When expressing a situation in which another structure is arranged on top of a certain structure, when it is simply described as "on", unless otherwise specified, it is assumed to include the following two situations: the other structure is arranged directly above the certain structure in a manner of being in contact with the certain structure; and the other structure is arranged above the certain structure via another structure.

[0030] <First embodiment>

[0031] Reference Figures 1 to 6C , a lighting device 1 according to an embodiment of the present invention is described.

[0032] [1. Structure of lighting device 1]

[0033] Figure 1 Schematic diagram showing the structure of an illumination device 1 according to an embodiment of the present invention. Figure 1 As shown, the lighting device 1 includes an optical element 10 , a light source 20 , a control device 30 and a power source 40 .

[0034] The optical element 10 includes four liquid crystal units 100 (a first liquid crystal unit 100-1, a second liquid crystal unit 100-2, a third liquid crystal unit 100-3, and a fourth liquid crystal unit 100-4). In the optical element 10, the first liquid crystal unit 100-1, the second liquid crystal unit 100-2, the third liquid crystal unit 100-3, and the fourth liquid crystal unit 100-4 are stacked in sequence along the z-axis direction from the unit close to the light source 20. It should be noted that, in the following, the structure of the optical element 10 including four liquid crystal units 100 is described, but the number of liquid crystal units 100 included in the optical element 10 is not limited to four. It is sufficient to include at least two liquid crystal units 100 in the optical element 10. The details of the structure of the optical element 10 will be described later.

[0035] The light source 20 can emit light to the optical element 10. The light emitted from the light source 20 is incident on the first liquid crystal unit 100-1, and is emitted from the fourth liquid crystal unit 100-4. In the lighting device 1, the diffusion and polarization of light are controlled by the four liquid crystal units 100 included in the optical element 10, and the light distribution of the light emitted from the fourth liquid crystal unit 100-4 can be changed. That is, the optical element 10 allows the light emitted from the light source 20 to pass in a diffusible manner, and the light distribution can be controlled. As the light source 20, for example, light emitting diodes (LEDs) can be used, but it is not limited to this. The light source 20 can be an element or device that can emit light.

[0036] The control device 30 is connected to the optical element 10 and can control the optical element 10. The control device 30 includes, for example, a central processing unit (CPU), a microprocessor (MPU), an integrated circuit (IC), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or a random access memory (RAM). Although detailed description will be omitted, the control device 30 is connected to the light source 20 and can also control the light source 20. It should be noted that the details of the structure of the control device 30 will be described later.

[0037] The power supply 40 is connected to the control device 30 and can supply power to the control device 30. That is, the power supply 40 can generate a predetermined voltage. For example, the power supply 40 can generate two voltages (for example, 3.3V and 30V), but is not limited to this. The power supply 40 may also include a voltage as GND (for example, 0V). It should be noted that in this specification, for convenience, even in the case of GND, it is sometimes described as generating a voltage.

[0038] Figure 2 1 is a block diagram showing the structure of an illumination device 1 according to an embodiment of the present invention. Figure 2 As shown, the control device 30 includes a signal generation circuit section 310 , a switch circuit section 320 , a first voltage signal line 330 - 1 , a second voltage signal line 330 - 2 , and a timing control signal line 340 .

[0039] The signal generation circuit unit 310 can perform arithmetic processing using data or information. Specifically, the signal generation circuit unit 310 can generate a plurality of voltage signals input to the liquid crystal unit 100 based on a predetermined program. In addition, the signal generation circuit unit 310 can generate a timing control signal for controlling the switch circuit unit 320 based on the voltage signal output from the signal generation circuit unit 310. The signal generation circuit unit 310 is, for example, an FPGA, but is not limited thereto.

[0040] The signal generation circuit section 310 and the switch circuit section 320 are connected via the first voltage signal line 330-1 and the second voltage signal line 330-2. Therefore, two voltage signals among the multiple voltage signals generated by the signal generation circuit section 310 are input to the switch circuit section 320 via the first voltage signal line 330-1 and the second voltage signal line 330-2. A digital analog conversion circuit (DAC) 331 and an amplifier circuit (AMP) 332 are connected to both the first voltage signal line 330-1 and the second voltage signal line 330-2. Voltages of 3.3V and 30V are supplied to the DAC331 and the AMP332 from the power supply 40, respectively. The voltage signal output from the signal generation circuit section 310 is converted into a digital signal by the DAC331, the voltage is amplified by the AMP332, and is input to the switch circuit section 320. It should be noted that, hereinafter, it is considered that the voltage signal output from the signal generation circuit section 310 includes a voltage signal converted into a digital signal by the DAC331 and the voltage is amplified by the AMP332.

[0041] The switch circuit section 320 includes 16 output channels CH (first output channel CH1 to sixteenth output channel CH16). The timing control signal is input to the switch circuit section 320 via the timing control signal line 340. The timing control signal includes information about two output channels CH that are connected (electrically connected) to the first voltage signal line 330-1 and the second voltage signal line 330-2. That is, the timing control signal includes information about the output channel CH selected according to the two voltage signals input from the signal generation circuit section 310 to the first voltage signal line 330-1 and the second voltage signal line 330-2. The switch circuit section 320 can be driven based on the timing control signal so that the first voltage signal line 330-1 and the second voltage signal line 330-2 are connected to two channels of the first output channel CH1 to the sixteenth output channel CH16. For example, the switch circuit section 320 is driven so that the first voltage signal line 330-1 and the second voltage signal line 330-2 are connected to the first output channel CH1 and the second output channel CH2, respectively. In this case, the two voltage signals generated in the signal generating circuit section 310 are input to the switch circuit section 320 via the first voltage signal line 330-1 and the second voltage signal line 330-2, and are output from the first output channel CH1 and the second output channel CH2. It should be noted that, in this case, the first voltage signal line 330-1 and the second voltage signal line 330-2 are not connected to the third output channel CH3 to the sixteenth output channel CH16. That is, the first voltage signal line 330-1 and the second voltage signal line 330-2 are in a non-conductive state with the third output channel CH3 to the sixteenth output channel CH16. That is, the third output channel CH3 to the sixteenth output channel are all in a high impedance state. The switch circuit section 320 is, for example, an analog switch circuit (ASW), but is not limited thereto.

[0042] The first output channel CH1 to the fourth output channel CH4 are connected via the flexible printed circuits (Flexible Printed Circuits: FPCs) 170 (refer to Figure 1 ) is connected to the first liquid crystal unit 100-1. The fifth output channel CH5 to the eighth output channel CH8 are connected to the second liquid crystal unit 100-2 via FPCs170. The ninth output channel CH9 to the twelfth output channel CH12 are connected to the third liquid crystal unit 100-3 via FPCs170. The thirteenth output channel CH13 to the sixteenth output channel CH16 are connected to the fourth liquid crystal unit 100-4 via FPCs170.

[0043] [2. Structure of the optical element 10]

[0044] Figure 3A and Figure 3BEach of them is a schematic cross-sectional view showing the structure of the lighting device 1 according to one embodiment of the present invention. Specifically, Figure 3A So Figure 1 A cross-sectional view of the optical element 10 obtained by cutting along the line A1-A2 of FIG. Figure 3B So Figure 1 A cross-sectional view of the optical element 10 obtained by cutting along the line B1-B2 of FIG.

[0045] like Figure 3A and Figure 3B As shown, the first liquid crystal unit 100-1 to the fourth liquid crystal unit 100-4 each include a first substrate 110-1, a second substrate 110-2, a plurality of first transparent electrodes 120-1, a plurality of second transparent electrodes 120-2, a plurality of third transparent electrodes 120-3, a plurality of fourth transparent electrodes 120-4, a first alignment film 130-1, a second alignment film 130-2, a sealing material 140 and a liquid crystal layer 150. On the first substrate 110-1, the first transparent electrodes 120-1 and the second transparent electrodes 120-2 are alternately arranged. In addition, on the first substrate 110-1, the first alignment film 130-1 is arranged in a manner covering the first transparent electrodes 120-1 and the second transparent electrodes 120-2. On the second substrate 110-2, the third transparent electrodes 120-3 and the fourth transparent electrodes 120-4 are alternately arranged. In addition, a second alignment film 130-2 is provided on the second substrate 110-2 in a manner covering the third transparent electrode 120-3 and the fourth transparent electrode 120-4. The first substrate 110-1 and the second substrate 110-2 are configured such that the first transparent electrode 120-1 and the second transparent electrode 120-2 are opposite to the third transparent electrode 120-3 and the fourth transparent electrode 120-4, and are bonded by a sealing material 140 provided at the periphery of the first substrate 110-1 and the second substrate 110-2. Liquid crystal is sealed in a space surrounded by the first substrate 110-1 (more specifically, the first alignment film 130-1), the second substrate 110-2 (more specifically, the second alignment film 130-2), and the sealing material 140, and a liquid crystal layer 150 is provided between the first substrate 110-1 and the second substrate 110-2.

[0046] An optical elastic resin layer 160 is provided between the first liquid crystal cell 100-1 and the second liquid crystal cell 100-2. Similarly, an optical elastic resin layer 160 is provided between the second liquid crystal cell 100-2 and the third liquid crystal cell 100-3 and between the third liquid crystal cell 100-3 and the fourth liquid crystal cell 100-4. For example, an adhesive containing a light-transmitting acrylic resin can be used as the optical elastic resin layer 160. That is, the optical elastic resin layer 160 can adhere and fix two adjacent liquid crystal cells 100.

[0047] As each of the first substrate 110-1 and the second substrate 110-2, for example, a glass substrate, a quartz substrate, or a sapphire substrate having light transmittance is used. In addition, as each of the first substrate 110-1 and the second substrate 110-2, for example, a polyimide resin substrate, an acrylic resin substrate, a siloxane resin substrate, or a fluororesin substrate having light transmittance can also be used.

[0048] The first transparent electrode 120-1, the second transparent electrode 120-2, the third transparent electrode 120-3, and the fourth transparent electrode 120-4 all function as electrodes for forming an electric field in the liquid crystal layer 150. As each of the first transparent electrode 120-1, the second transparent electrode 120-2, the third transparent electrode 120-3, and the fourth transparent electrode 120-4, for example, a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) is used.

[0049] In the first liquid crystal cell 100-1 and the second liquid crystal cell 100-2, the first transparent electrode 120-1 and the second transparent electrode 120-2 extend along the x-axis direction, and the third transparent electrode 120-3 and the fourth transparent electrode 120-4 extend along the y-axis direction. In addition, in the third liquid crystal cell 100-3 and the fourth liquid crystal cell 100-4, the first transparent electrode 120-1 and the second transparent electrode 120-2 extend along the y-axis direction, and the third transparent electrode 120-3 and the fourth transparent electrode 120-4 extend along the x-axis direction.

[0050] It should be noted that, hereinafter, when the first to fourth transparent electrodes 120 - 1 to 120 - 4 are not particularly distinguished, they may be described as transparent electrodes 120 .

[0051] Each of the first alignment film 130-1 and the second alignment film 130-2 aligns the liquid crystal molecules in the liquid crystal layer 150 in a predetermined direction. As each of the first alignment film 130-1 and the second alignment film 130-2, a polyimide resin or the like is used. It should be noted that each of the first alignment film 130-1 and the second alignment film 130-2 can also be given an alignment characteristic by an alignment treatment such as a rubbing method or a photo-alignment method. The rubbing method is a method of rubbing the surface of the alignment film in one direction. In addition, the photo-alignment method is a method of irradiating the alignment film with linearly polarized ultraviolet rays.

[0052] The first alignment film 130-1 is subjected to an alignment treatment so that the liquid crystal molecules on the first substrate 110-1 side of the liquid crystal layer 150 are arranged in a direction orthogonal to the extension direction of the first transparent electrode 120-1 and the second transparent electrode 120-2. In addition, the second alignment film 130-2 is subjected to an alignment treatment so that the liquid crystal molecules on the second substrate 110-2 side of the liquid crystal layer 150 are arranged in a direction orthogonal to the extension direction of the third transparent electrode 120-3 and the fourth transparent electrode 120-4. Therefore, in the first liquid crystal unit 100-1 and the second liquid crystal unit 100-2, the long axis of the liquid crystal molecules on the first substrate 110-1 side is aligned along the y-axis direction, and the long axis of the liquid crystal molecules on the second substrate 110-2 side is aligned along the x-axis direction. In addition, in the third liquid crystal unit 100-3 and the fourth liquid crystal unit 100-4, the long axis of the liquid crystal molecules on the first substrate 110-1 side is aligned along the x-axis direction, and the long axis of the liquid crystal molecules on the second substrate 110-2 side is aligned along the y-axis direction.

[0053] As the sealing material 140, an adhesive material including epoxy resin or acrylic resin is used. It should be noted that the adhesive material may be an ultraviolet curing type or a thermosetting type.

[0054] The liquid crystal layer 150 can refract the transmitted light or change the polarization state of the transmitted light according to the orientation state of the liquid crystal molecules. As the liquid crystal of the liquid crystal layer 150, nematic liquid crystal or the like is used. The liquid crystal described in this embodiment is a positive type, but a negative type structure can also be applied by changing the orientation direction of the liquid crystal molecules in a state where no voltage is applied to the transparent electrode 120. In addition, it is preferred that the liquid crystal contains a chiral agent that imparts a twist to the liquid crystal molecules.

[0055] [3. Electrode Pattern of Liquid Crystal Cell 100]

[0056] Figure 4A and Figure 4B 1 and 2 are schematic top views showing electrode patterns of a liquid crystal unit 100 included in an optical element 10 of an illumination device 1 according to an embodiment of the present invention. Specifically, Figure 4A is a top view showing an electrode pattern formed on the first substrate 110 - 1 of the first liquid crystal cell 100 - 1, Figure 4B 1 is a top view showing an electrode pattern formed on the second substrate 110-2 of the first liquid crystal unit 100-1. The first substrate 110-1 and the second substrate 110-2 are Figure 4A The electrode pattern shown is similar to Figure 4B The electrode patterns shown are bonded in a manner that they face each other.

[0057] like Figure 4AAs shown, a first connection pad 121-1 and a second connection pad 121-2 are provided on the first substrate 110-1. A plurality of first transparent electrodes 120-1 are electrically connected to the first connection pad 121-1. A plurality of second transparent electrodes 120-2 are electrically connected to the second connection pad 121-2.

[0058] like Figure 4B As shown, a third connection pad 121-3, a fourth connection pad 121-4, a first terminal 122-1, a second terminal 122-2, a third terminal 122-3 and a fourth terminal 122-4 are provided on the second substrate 110-2. A plurality of third transparent electrodes 120-3 are electrically connected to the third terminal 122-3. A plurality of fourth transparent electrodes 120-4 are electrically connected to the fourth terminal 122-4. In addition, the third connection pad 121-3 is electrically connected to the first terminal 122-1. The fourth connection pad 121-4 is electrically connected to the second terminal 122-2.

[0059] When the first substrate 110-1 is attached to the second substrate 110-2, the first connection pad 121-1 and the second connection pad 121-2 overlap with the third connection pad 121-3 and the fourth connection pad 121-4, respectively. A conduction electrode is provided between the first connection pad 121-1 and the third connection pad 121-3, and the first connection pad 121-1 and the third connection pad 121-3 are electrically connected via the conduction electrode. Similarly, a conduction electrode is also provided between the second connection pad 121-2 and the fourth connection pad 121-4, and the second connection pad 121-2 and the fourth connection pad 121-4 are electrically connected via the conduction electrode. Therefore, the first transparent electrode 120-1 and the second transparent electrode 120-2 on the first substrate 110-1 are electrically connected to the first terminal 122-1 and the second terminal 122-2, respectively.

[0060] The electrode pattern of the second liquid crystal cell 100-2 is the same as that of the first liquid crystal cell 100-1. The electrode pattern structures of the third and fourth liquid crystal cells 100-3 and 100-4 are the same as that of the first liquid crystal cell 100-1, except that the extending directions of the transparent electrodes 120 differ by 90°.

[0061] In the liquid crystal cell 100, the first terminal 122-1 to the fourth terminal 122-4 on the second substrate 110-2 are exposed from the first substrate 110-1. In each of the first liquid crystal cell 100-1 to the fourth liquid crystal cell 100-4, an FPCs 170 (see Figure 1 ).

[0062] The first output channel CH1 to the fourth output channel CH4 are electrically connected to the first terminal 122-1 to the fourth terminal 122-4 of the first liquid crystal unit 100-1 via the FPCs 170. The fifth output channel CH5 to the eighth output channel CH8 are electrically connected to the first terminal 122-1 to the fourth terminal 122-4 of the second liquid crystal unit 100-2 via the FPCs 170. The ninth output channel CH9 to the twelfth output channel CH12 are electrically connected to the first terminal 122-1 to the fourth terminal 122-4 of the third liquid crystal unit 100-3 via the FPCs 170. The thirteenth output channel CH13 to the sixteenth output channel CH16 are electrically connected to the first terminal 122-1 to the fourth terminal 122-4 of the fourth liquid crystal unit 100-4 via the FPCs 170. Therefore, the control device 30 can input voltage signals to the first transparent electrodes 120-1 to the fourth transparent electrodes 120-4 of the liquid crystal unit 100 respectively via the FPCs 170, and control the optical element 10.

[0063] [4. Optical Characteristics of Liquid Crystal Cell 100]

[0064] Figure 5A and Figure 5B Each of them is a schematic diagram for explaining the optical characteristics of the liquid crystal unit 100 included in the optical element 10 of the lighting device 1 according to one embodiment of the present invention. Specifically, Figure 5A FIG. 1 shows the liquid crystal cell 100 in a state where no voltage is applied to the transparent electrode 120. Figure 5B The liquid crystal cell 100 is shown in a state where a voltage is applied to the transparent electrode 120 .

[0065] like Figure 5A As shown, the liquid crystal molecules of the liquid crystal layer 150 on the first substrate 110-1 side are oriented along the y-axis direction, and the liquid crystal molecules of the liquid crystal layer 150 on the second substrate 110-2 side are oriented along the x-axis direction. Therefore, when no voltage is applied to the first transparent electrode 120-1 to the fourth transparent electrode 120-4, the liquid crystal molecules in the liquid crystal layer 150 are oriented in a manner of twisting 90° along the c-axis direction as they move from the first substrate 110-1 toward the second substrate 110-2. In addition, the polarization plane (the direction of the polarization axis or polarization component) of the light passing through the liquid crystal layer 150 is rotated 90° following the orientation direction of the liquid crystal molecules. That is, the light passing through the liquid crystal layer 150 (more specifically, the polarization component of the transmitted light) is optically rotated.

[0066] On the other hand, when a voltage is applied between two adjacent transparent electrodes 120 to generate a potential difference, an electric field (hereinafter referred to as a "lateral electric field") is generated between the two adjacent transparent electrodes 120, and the orientation of the liquid crystal molecules changes. Figure 5BAs shown, in a state where the liquid crystal molecules in the liquid crystal layer 150 are oriented in a manner of twisting 90° along the c-axis direction from the first substrate 110-1 toward the second substrate 110-2, the liquid crystal molecules near the first substrate 110-1 side are arranged in a convex arc shape relative to the first substrate 110-1 by the lateral electric field between the first transparent electrode 120-1 and the second transparent electrode 120-2, and the liquid crystal molecules near the second substrate 110-2 side are arranged in a convex arc shape relative to the second substrate 110-2 by the lateral electric field between the third transparent electrode 120-3 and the fourth transparent electrode 120-4. The liquid crystal molecules arranged in a convex arc shape have a refractive index distribution, and have light diffusion in the same polarization direction as the orientation direction of the liquid crystal molecules. It should be noted that, compared with the distance between two adjacent transparent electrodes, the interval between the first substrate 110-1 and the second substrate 110-2, that is, the unit gap d is sufficiently large (for example, 8μm≤d≤50μm, preferably 10μm≤d≤30μm, and more preferably 15μm≤d≤25μm), so the electric field formed between the above-mentioned transparent electrodes 120 is unlikely to affect the liquid crystal molecules located near the center between the first substrate 110-1 and the second substrate 110-2.

[0067] The light emitted from the light source 20 includes a polarization component in the x-axis direction (hereinafter referred to as the "P polarization component") and a polarization component in the y-axis direction (hereinafter referred to as the "S polarization component"). However, in the following, for convenience, the light emitted from the light source 20 is divided into a first light 1000-1 having a P polarization component and a second light 1000-2 having an S polarization component for explanation.

[0068] The P polarization component of the first light 1000-1 incident from the first substrate 110-1 side is different from the alignment direction of the liquid crystal molecules on the first substrate 110-1 side, so the first light 1000-1 is not diffused (refer to Figure 5B In addition, the first light 1000-1 is optically rotated in the process of passing through the liquid crystal layer 150, and the polarization component changes from the P polarization component to the S polarization component. The S polarization component of the first light 1000-1 is different from the orientation direction of the liquid crystal molecules on the second substrate 110-2 side, so the first light 1000-1 does not diffuse (refer to Figure 5B (2) in the figure.

[0069] The S polarization component of the second light 1000-2 incident from the first substrate 110-1 side is in the same direction as the alignment direction of the liquid crystal molecules on the first substrate 110-1 side. Therefore, the second light 1000-2 is diffused along the y-axis direction according to the refractive index distribution of the liquid crystal molecules (refer to Figure 5B(3) in FIG. 1 ). In addition, the second light 1000-2 is optically rotated in the process of passing through the liquid crystal layer 150, and the polarization component changes from the S polarization component to the P polarization component. The P polarization component of the second light 1000-2 is in the same orientation direction as the liquid crystal molecules on the second substrate 110-2 side. Therefore, the second light 1000-2 diffuses along the x-axis direction according to the refractive index distribution of the liquid crystal molecules (refer to FIG. Figure 5B (4) in the figure.

[0070] [5. Control of light distribution by lighting device 1]

[0071] Figure 6A to Figure 6C 1 is a timing chart showing voltage signals input to the transparent electrodes 120 of the liquid crystal cells 100 for controlling light distribution in the lighting device 1 according to one embodiment of the present invention. In the lighting device 1 according to the present embodiment, predetermined voltage signals are sequentially input to the first transparent electrodes 120-1 to the fourth transparent electrodes 120-4 of the first liquid crystal cells 100-1 to the fourth liquid crystal cells 100-4, so that each liquid crystal cell 100 is time-division driven. That is, in the lighting device 1, the light distribution of light transmitted through the optical element 10 can be controlled by time-division driving the plurality of liquid crystal cells 100 based on one signal generation circuit unit 310. More specifically, in the lighting device 1 according to the present embodiment, a plurality of liquid crystal cells 100 are connected to a switch circuit section 320, and a pair of analog conversion circuits 331 and amplifier circuits 332 are provided between the switch circuit section 320 and the signal generation circuit section 310. The connection states of the analog conversion circuits 331 and amplifier circuits 332 and the transparent electrodes 120 of the liquid crystal cells 100 are switched in a time-division manner through the switch circuit section 320, thereby enabling time-division driving of the liquid crystal cells 100. A specific example of time-division driving will be described in detail below.

[0072] Fig. 6A is a timing chart for controlling the optical element 10 so that the light distribution shape becomes a circular shape. Figure 6B is a timing chart for controlling the optical element 10 so that the light distribution shape becomes a line shape extending in the x-axis direction. Figure 6C This is a timing chart for controlling the optical element 10 so that the light distribution shape becomes a line shape extending in the y-axis direction.

[0073] exist Figure 6A to Figure 6C, the voltage signals output from the first output channel CH1 to the fourth output channel CH4 are respectively input to the first transparent electrode 120-1 to the fourth transparent electrode 120-4 of the first liquid crystal unit 100-1. The voltage signals output from the fifth output channel CH5 to the eighth output channel CH8 are respectively input to the first transparent electrode 120-1 to the fourth transparent electrode 120-4 of the second liquid crystal unit 100-2. The voltage signals output from the ninth output channel CH9 to the twelfth output channel CH12 are respectively input to the first transparent electrode 120-1 to the fourth transparent electrode 120-4 of the third liquid crystal unit 100-3. The voltage signals output from the thirteenth output channel CH13 to the sixteenth output channel CH16 are respectively input to the first transparent electrode 120-1 to the fourth transparent electrode 120-4 of the fourth liquid crystal unit 100-4.

[0074] In the lighting device 1, as Figure 6A to Figure 6C As shown in FIG. 1 , one frame period is divided into eight sub-frame periods SF (a first sub-frame period SF1 to an eighth sub-frame period SF8 ).

[0075] [5-1. Circular light distribution]

[0076] like Fig. 6A As shown, in the first subframe period SF1, a first voltage signal having a rectangular wave is output from the first output channel CH1, and a second voltage signal having a rectangular wave is output from the second output channel CH2. The phase of the first voltage signal is opposite to the phase of the second voltage signal. In other words, the phase of the first voltage signal is 180° different from the phase of the second voltage signal. On the other hand, the third output channel CH3 to the sixteenth output channel CH16 are in a high impedance state (High-Z).

[0077] During the first subframe period SF1, the first voltage signal and the second voltage signal generated by the signal generation circuit section 310 are input to the switch circuit section 320 via the first voltage signal line 330-1 and the second voltage signal line 330-2, respectively. The switch circuit section 320 drives so that the first voltage signal line 330-1 and the second voltage signal line 330-2 are respectively connected to the first output channel CH1 and the second output channel CH2. Therefore, during the first subframe period SF1, as described above, the first voltage signal and the second voltage signal are respectively output from the first output channel CH1 and the second output channel CH2. On the other hand, since the first voltage signal line 330-1 and the second voltage signal line 330-2 are in a non-conductive state with the third output channel CH3 to the sixteenth output channel CH16, the third output channel CH3 to the sixteenth output channel CH16 are in a high impedance state.

[0078] Therefore, during the first subframe period SF1, a high voltage or a low voltage is applied to the first transparent electrode 120-1 and the second transparent electrode 120-2 of the first liquid crystal unit 100-1, respectively. That is, during the first subframe period SF1, a lateral electric field is generated between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the first liquid crystal unit 100-1.

[0079] In the second subframe period SF2, the third voltage signal having a rectangular wave and the fourth voltage signal having a rectangular wave generated by the signal generation circuit section 310 are input to the switch circuit section 320 via the first voltage signal line 330-1 and the second voltage signal line 330-2, respectively. Here, the phase of the third voltage signal is opposite to the phase of the fourth voltage signal. The switch circuit section 320 drives so that the first voltage signal line 330-1 and the second voltage signal line 330-2 are respectively connected to the third output channel CH3 and the fourth output channel CH4. Therefore, in the second subframe period SF2, the third voltage signal and the fourth voltage signal are output from the third output channel CH3 and the fourth output channel CH4, respectively. On the other hand, since the first voltage signal line 330-1 and the second voltage signal line 330-2 are in a non-conductive state with the first output channel CH1, the second output channel CH2, and the fifth output channel CH5 to the sixteenth output channel CH16, the first output channel CH1, the second output channel CH2, and the fifth output channel CH5 to the sixteenth output channel CH16 are in a high impedance state.

[0080] Therefore, in the second subframe period SF2, a high voltage (Hgih) or a low voltage (Low) is applied to the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the first liquid crystal unit 100-1, respectively. That is, in the second subframe period SF2, a transverse electric field is generated between the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the first liquid crystal unit 100-1.

[0081] It should be noted that, in the second subframe period SF2, since the first output channel CH1 and the second output channel CH2 are in a high impedance state, the high (High) voltage or the low (Low) voltage applied to the first transparent electrode 120-1 and the second transparent electrode 120-2 of the first liquid crystal unit 100-1 is maintained through the capacitance of the liquid crystal of the liquid crystal layer 150. Therefore, even in the second subframe period SF2, a lateral electric field is maintained between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the first liquid crystal unit 100-1.

[0082] The same is true for the third subframe period SF3 to the eighth subframe period. That is, in the third subframe period SF3 and the fourth subframe period SF4, a transverse electric field is generated between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the second liquid crystal unit 100-2 and between the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the second liquid crystal unit 100-2. In the fifth subframe period SF5 and the sixth subframe period SF6, a transverse electric field is generated between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the third liquid crystal unit 100-3 and between the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the third liquid crystal unit 100-3. In the seventh subframe period SF7 and the eighth subframe period SF8, a transverse electric field is generated between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the fourth liquid crystal unit 100-4 and between the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the fourth liquid crystal unit 100-4.

[0083] Since the output channel CH which does not output a voltage signal is also in a high impedance state during the third subframe period SF3 to the eighth subframe period SF8 , the high voltage or low voltage applied to the transparent electrode 120 is maintained through the capacitance of the liquid crystal in the liquid crystal layer 150 .

[0084] Therefore, the diffusion characteristics of the first liquid crystal unit 100-1 to the fourth liquid crystal unit 100-4 in one frame period are as shown in Table 1. In the first subframe period SF1 to the eighth subframe period SF8, the lateral electric field is controlled to be generated between the two transparent electrodes 120 adjacent to each other on the one substrate 110 side of the liquid crystal unit 100. However, since the capacitance of the liquid crystal of the liquid crystal layer 150 maintains the high voltage or low voltage applied to the transparent electrode 120, the first liquid crystal unit 100-1 to the fourth liquid crystal unit 100-4 have the diffusion characteristics as shown in Table 1 in one frame period. In this case, the P polarization component and the S polarization component of the light emitted from the light source 20 are diffused in the x-axis direction and the y-axis direction respectively by the optical element 10. Therefore, the light emitted from the light source 20 is controlled by the optical element 10 to have a circular light distribution. It should be noted that by changing the magnitude of the high voltage and the low voltage applied to each transparent electrode 120, it is also possible to control the light distribution to have an elliptical shape.

[0085] [Table 1]

[0086]

[0087] The cycle of one frame period is 30 Hz or more and 120 Hz or less, and preferably 60 Hz. When the cycle of one frame period is within the above range, the voltage applied to the transparent electrode 120 can be maintained by the capacitance of the liquid crystal of the liquid crystal layer 150 .

[0088] [5-2. Light distribution in a linear shape extending in the x-axis direction]

[0089] like Figure 6B As shown, during the first subframe period SF1, the first voltage signal and the second voltage signal having an intermediate voltage (a voltage between a high voltage and a low voltage) generated by the signal generation circuit section 310 are input to the switch circuit section 320 via the first voltage signal line 330-1 and the second voltage signal line 330-2, respectively. The intermediate voltage is a fixed voltage, and the phase of the first voltage signal is the same as the phase of the second voltage signal. The switch circuit section 320 drives so that the first voltage signal line 330-1 and the second voltage signal line 330-2 are respectively connected to the first output channel CH1 and the second output channel CH2. Therefore, during the first subframe period SF1, the first voltage signal and the second voltage signal are output from the first output channel CH1 and the second output channel CH2, respectively. On the other hand, since the first voltage signal line 330-1 and the second voltage signal line 330-2 are in a non-conductive state with the third output channel CH3 to the sixteenth output channel CH16, the third output channel CH3 to the sixteenth output channel CH16 become a high impedance state.

[0090] Therefore, in the first subframe period SF1, an intermediate voltage is applied to the first transparent electrode 120-1 and the second transparent electrode 120-2 of the first liquid crystal unit 100-1. In this case, the first transparent electrode 120-1 and the second transparent electrode 120-2 are at the same potential, and no lateral electric field is generated between the first transparent electrode 120-1 and the second transparent electrode 120-2.

[0091] Figure 6B The second subframe period SF2 shown in FIG. Fig. 6A The second subframe period SF2 shown is the same, so the description is omitted.

[0092] Therefore, in the second subframe period SF2, a high voltage or a low voltage is applied to the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the first liquid crystal unit 100-1, respectively. That is, in the second subframe period SF2, a transverse electric field is generated between the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the first liquid crystal unit 100-1.

[0093] It should be noted that, in the second subframe period SF2, since the first output channel CH1 and the second output channel CH2 are in a high impedance state, the intermediate voltage applied to the first transparent electrode 120-1 and the second transparent electrode 120-2 of the first liquid crystal unit 100-1 is maintained through the capacitance of the liquid crystal of the liquid crystal layer 150. Therefore, in the first subframe period SF1 and the second subframe period SF2, a transverse electric field is generated only between the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the first liquid crystal unit 100-1.

[0094] The same is true for the third subframe period SF3 to the eighth subframe period. That is, in the third subframe period SF3 and the fourth subframe period SF4, a transverse electric field is generated only between the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the second liquid crystal unit 100-2. In the fifth subframe period SF5 and the sixth subframe period SF6, a transverse electric field is generated only between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the third liquid crystal unit 100-3. In the seventh subframe period SF7 and the eighth subframe period SF8, a transverse electric field is generated only between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the fourth liquid crystal unit 100-4.

[0095] Since the output channel CH that does not output a voltage signal is also in a high impedance state during the third subframe period SF3 to the eighth subframe period SF8, the high voltage, low voltage or intermediate voltage applied to the transparent electrode 120 is maintained through the capacitance of the liquid crystal in the liquid crystal layer 150.

[0096] Therefore, the diffusion characteristics of the first liquid crystal unit 100-1 to the fourth liquid crystal unit 100-4 in one frame period are as shown in Table 2. In each of the second sub-frame period SF2, the fourth sub-frame period SF4, the fifth sub-frame period SF5 and the seventh sub-frame period SF7, a lateral electric field is controlled to be generated between two adjacent transparent electrodes 120 on one substrate 110 side of the liquid crystal unit 100. In addition, in each of the first sub-frame period SF1, the third sub-frame period SF3, the sixth sub-frame period SF6 and the eighth sub-frame period SF8, an intermediate voltage is controlled to be applied to the two transparent electrodes 120 on the other substrate 110 side of the liquid crystal unit 100. However, since the high voltage, low voltage or intermediate voltage applied to the transparent electrode 120 is maintained by the capacitance of the liquid crystal of the liquid crystal layer 150, the first liquid crystal unit 100-1 to the fourth liquid crystal unit 100-4 have the diffusion characteristics shown in Table 2 in one frame period. In this case, both the P polarization component and the S polarization component of the light emitted from light source 20 are diffused only in the x-axis direction by optical element 10. Therefore, the light emitted from light source 20 is controlled by optical element 10 to have a linear light distribution extending in the x-axis direction.

[0097] [Table 2]

[0098]

[0099] The high voltage, low voltage and intermediate voltage are +15V, -15V and 0V respectively, but are not limited thereto. The high voltage, low voltage and intermediate voltage may be +30V, 0V and +15V respectively. It should be noted that the above voltage values ​​are examples and are not limited thereto.

[0100] [5-3. Linear light distribution extending in the y-axis direction]

[0101] Figure 6C The first subframe period SF1 shown in FIG. Fig. 6A The first subframe period SF1 shown is the same, and thus the description thereof is omitted.

[0102] Therefore, during the first subframe period SF1, a high voltage or a low voltage is applied to the first transparent electrode 120-1 and the second transparent electrode 120-2 of the first liquid crystal unit 100-1, respectively. That is, during the first subframe period SF1, a lateral electric field is generated between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the first liquid crystal unit 100-1.

[0103] like Figure 6C As shown, in the second subframe period SF2, the third voltage signal and the fourth voltage signal having the intermediate voltage generated by the signal generation circuit section 310 are input to the switch circuit section 320 via the first voltage signal line 330-1 and the second voltage signal line 330-2, respectively. The switch circuit section 320 drives so that the first voltage signal line 330-1 and the second voltage signal line 330-2 are respectively connected to the third output channel CH3 and the fourth output channel CH4. Therefore, in the second subframe period SF2, the third voltage signal and the fourth voltage signal are respectively output from the third output channel CH3 and the fourth output channel CH4. On the other hand, since the first voltage signal line 330-1 and the second voltage signal line 330-2 are in a non-conductive state with the first output channel CH1, the second output channel CH2, and the fifth output channel CH5 to the sixteenth output channel CH16, the first output channel CH1, the second output channel CH2, and the fifth output channel CH5 to the sixteenth output channel CH16 become a high impedance state.

[0104] Therefore, in the second subframe period SF2, the intermediate voltage is applied to the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the first liquid crystal unit 100-1. In this case, the third transparent electrode 120-3 and the fourth transparent electrode 120-4 are at the same potential, and no lateral electric field is generated between the third transparent electrode 120-3 and the fourth transparent electrode 120-4.

[0105] It should be noted that, in the second subframe period SF2, since the first output channel CH1 and the second output channel CH2 are in a high impedance state, the high (High) voltage or the low (Low) voltage applied to the first transparent electrode 120-1 and the second transparent electrode 120-2 of the first liquid crystal unit 100-1 is maintained through the capacitance of the liquid crystal of the liquid crystal layer 150. Therefore, in the first subframe period SF1 and the second subframe period SF2, a transverse electric field is generated only between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the first liquid crystal unit 100-1.

[0106] The same is true for the third subframe period SF3 to the eighth subframe period SF8. That is, in the third subframe period SF3 and the fourth subframe period SF4, a transverse electric field is generated only between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the second liquid crystal unit 100-2. In the fifth subframe period SF5 and the sixth subframe period SF6, a transverse electric field is generated only between the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the third liquid crystal unit 100-3. In the seventh subframe period SF7 and the eighth subframe period SF8, a transverse electric field is generated only between the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the fourth liquid crystal unit 100-4.

[0107] Since the output channel CH that does not output a voltage signal is also in a high impedance state during the third subframe period SF3 to the eighth subframe period SF8, the high voltage, low voltage or intermediate voltage applied to the transparent electrode 120 is maintained through the capacitance of the liquid crystal in the liquid crystal layer 150.

[0108] Therefore, the diffusion characteristics of the first liquid crystal unit 100-1 to the fourth liquid crystal unit 100-4 in one frame period are as shown in Table 3. In each of the first subframe period SF1, the third subframe period SF3, the sixth subframe period SF6, and the eighth subframe period SF8, a lateral electric field is controlled to be generated between two transparent electrodes 120 adjacent to one substrate 110 of the liquid crystal unit 100. In addition, in each of the second subframe period SF2, the fourth subframe period SF4, the fifth subframe period SF5, and the seventh subframe period SF7, an intermediate voltage is controlled to be applied to the two transparent electrodes 120 on the other substrate 110 side of the liquid crystal unit 100. However, since the high voltage, low voltage, or intermediate voltage applied to the transparent electrode 120 is maintained by the capacitance of the liquid crystal of the liquid crystal layer 150, the first liquid crystal unit 100-1 to the fourth liquid crystal unit 100-4 have the diffusion characteristics shown in Table 3 in one frame period. In this case, the P polarization component and the S polarization component of the light emitted from the light source 20 are diffused only in the y-axis direction by the optical element 10. Therefore, the light emitted from the light source 20 is controlled by the optical element 10 to have a linear distribution extending in the y-axis direction.

[0109] [Table 3]

[0110]

[0111] As described above, in the control of light distribution by the lighting device 1 according to the present embodiment, one frame is divided into a plurality of sub-frame periods SF. In each sub-frame period SF, the output channel of the switch circuit unit 320 is switched according to two voltage signals input from the signal generation circuit unit 310 to a pair of voltage signal lines 330 (the first voltage signal line 330-1 and the second voltage signal line), and two voltage signals are input to two adjacent transparent electrodes 120, respectively. Therefore, the number of voltage signal lines 330 can be reduced to be less than the number of transparent electrodes 120, and as a result, the number of DACs and AMPs can be reduced. Therefore, in the lighting device 1, the control device 30 can be miniaturized and the manufacturing cost can be reduced.

[0112] <Second embodiment>

[0113] Reference Figure 7 and Figure 8 , a lighting device 1A according to an embodiment of the present invention will be described. It should be noted that when the structure of the lighting device 1A is the same as that of the lighting device 1, the description of the structure of the lighting device 1A may be omitted.

[0114] [1. Structure of lighting device 1A]

[0115] Figure 71 is a block diagram showing the structure of a lighting device 1A according to an embodiment of the present invention. Figure 7 As shown, the lighting device 1A includes an optical element 10, a light source 20, a control device 30A and a power source 40. The control device 30A includes a signal generating circuit portion 310, a switch circuit portion 320A, a first voltage signal line 330-1, a second voltage signal line 330-2, a third voltage signal line 330-3, a fourth voltage signal line 330-4, and a timing control signal line 340.

[0116] The signal generation circuit unit 310 and the switch circuit unit 320A are connected via the first to fourth voltage signal lines 330-1 to 330-4. Therefore, four voltage signals among the plurality of voltage signals generated by the signal generation circuit unit 310 are input to the switch circuit unit 320 via the first to fourth voltage signal lines 330-1 to 330-4.

[0117] The switch circuit section 320A can be driven based on the timing control signal so that the first voltage signal line 330-1 to the fourth voltage signal line 330-4 are connected to the first output channel CH1 to the sixteenth output channel CH16. For example, the switch circuit section 320A can be driven based on the timing control signal so that the first voltage signal line 330-1 to the fourth voltage signal line 330-4 are connected to the first output channel CH1 to the fourth output channel CH4. It should be noted that at this time, the first voltage signal line 330-1 to the fourth voltage signal line 330-4 and the fifth output channel CH5 to the sixteenth output channel CH16 are in a non-conductive state. That is, the fifth output channel CH5 to the sixteenth output channel CH16 are all in a high impedance state.

[0118] [2. Control of light distribution by lighting device 1A]

[0119] Figure 81 is a timing chart showing voltage signals input to the transparent electrodes 120 of the liquid crystal cells 100 for controlling light distribution in the lighting device 1A according to one embodiment of the present invention. In the lighting device 1A according to the present embodiment, predetermined voltage signals are sequentially input to the first transparent electrodes 120-1 to the fourth transparent electrodes 120-4 of the first liquid crystal cells 100-1 to the fourth liquid crystal cells 100-4, so that each liquid crystal cell 100 is time-division driven. That is, in the lighting device 1A, the light distribution of light transmitted through the optical element 10 can be controlled by time-division driving the plurality of liquid crystal cells 100 based on one signal generation circuit unit 310. More specifically, in the lighting device 1A according to the present embodiment, a plurality of liquid crystal cells 100 are connected to a switch circuit section 320A, and two pairs of analog conversion circuits 331 and amplifier circuits 332 are provided between the switch circuit section 320 and the signal generation circuit section 310. The connection states of the analog conversion circuits 331 and amplifier circuits 332 and the transparent electrodes 120 of the liquid crystal cells 100 are switched in a time-division manner through the switch circuit section 320A, thereby enabling time-division driving of the liquid crystal cells 100. A specific example of time-division driving will be described in detail below.

[0120] Figure 8 This is a timing diagram for controlling the optical element 10 so that the light distribution shape becomes a circular shape. However, in the lighting device 1A, the light distribution shape controlled by the optical element 10 is not limited to this. In the lighting device 1A, similarly to the lighting device 1, the light distribution shape may also be a linear shape extending in the x-axis direction or the y-axis direction.

[0121] In the lighting device 1A, as Figure 8 As shown in FIG. 1 , one frame period is divided into four sub-frame periods (a first sub-frame period SF1 to a fourth sub-frame period SF4 ).

[0122] During the first subframe period SF1, the first to fourth voltage signals having rectangular waves generated by the signal generation circuit section 310 are input to the switch circuit section 320A via the first to fourth voltage signal lines 330-1 to 330-4, respectively. Here, the phase of the first voltage signal is opposite to that of the second voltage signal, and the phase of the third voltage signal is opposite to that of the fourth voltage signal. The switch circuit section 320 drives so that the first to fourth voltage signal lines 330-1 to 330-4 are respectively connected to the first to fourth output channels CH1 to CH4. Therefore, during the first subframe period SF1, the first to fourth voltage signals are respectively output from the first to fourth output channels CH1 to CH4. On the other hand, since the first to fourth voltage signal lines 330-1 to 330-4 are in a non-conductive state with the fifth to sixteenth output channels CH5 to CH16, the fifth to sixteenth output channels CH5 to CH16 are in a high impedance state.

[0123] Therefore, during the first subframe period SF1, a high voltage or a low voltage is applied to the first transparent electrode 120-1 to the fourth transparent electrode 120-4 of the first liquid crystal unit 100-1, respectively. That is, during the first subframe period SF1, a lateral electric field is generated between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the first liquid crystal unit 100-1 and between the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the first liquid crystal unit 100-1.

[0124] During the second subframe period, the fifth voltage signal to the eighth voltage signal having a rectangular wave generated by the signal generation circuit section 310 are input to the switch circuit section 320A via the first voltage signal line 330-1 to the fourth voltage signal line 330-4, respectively. Here, the phase of the fifth voltage signal is opposite to the phase of the sixth voltage signal, and the phase of the seventh voltage signal is opposite to the movement of the eighth voltage signal. The switch circuit section 320 is driven so that the first voltage signal line 330-1 to the fourth voltage signal line 330-4 are respectively connected to the fifth output channel CH5 to the eighth output channel CH8. Therefore, during the second subframe period SF2, the fifth voltage signal to the eighth voltage signal are respectively output from the fifth output channel CH5 to the eighth output channel CH8. On the other hand, since the first voltage signal line 330-1 to the fourth voltage signal line 330-4 and the first output channel CH1 to the fourth output channel CH4 and the ninth output channel CH9 to the sixteenth output channel CH16 are in a non-conducting state, the first output channel CH1 to the fourth output channel CH4 and the ninth output channel CH9 to the sixteenth output channel CH16 are in a high impedance state.

[0125] Therefore, during the second subframe period SF2, a high voltage or a low voltage is applied to the first transparent electrode 120-1 to the fourth transparent electrode 120-4 of the second liquid crystal unit 100-2, respectively. That is, during the second subframe period SF2, a lateral electric field is generated between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the second liquid crystal unit 100-2 and between the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the second liquid crystal unit 100-2.

[0126] It should be noted that, in the second subframe period SF2, since the first output channel CH1 to the fourth output channel CH4 are in a high impedance state, the high (High) voltage or the low (Low) voltage applied to the first transparent electrode 120-1 to the fourth transparent electrode 120-4 of the first liquid crystal unit 100-1 is maintained through the capacitance of the liquid crystal of the liquid crystal layer 150. Therefore, even in the second subframe period SF2, a lateral electric field is maintained between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the first liquid crystal unit 100-1 and between the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the first liquid crystal unit 100-1.

[0127] The same is true for the third subframe period SF3 and the fourth subframe period SF4. That is, in the third subframe period SF3, a transverse electric field is generated between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the third liquid crystal unit 100-3 and between the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the third liquid crystal unit 100-3. In the fourth subframe period SF4, a transverse electric field is generated between the first transparent electrode 120-1 and the second transparent electrode 120-2 of the fourth liquid crystal unit 100-4 and between the third transparent electrode 120-3 and the fourth transparent electrode 120-4 of the fourth liquid crystal unit 100-4.

[0128] Since the output channel CH which does not output a voltage signal is also in a high impedance state during the third subframe period SF3 and the fourth subframe period SF4 , the high voltage or low voltage applied to the transparent electrode 120 is maintained through the capacitance of the liquid crystal of the liquid crystal layer 150 .

[0129] Therefore, the diffusion characteristics of the first liquid crystal unit 100-1 to the fourth liquid crystal unit 100-4 during one frame have the diffusion characteristics shown in Table 1. In this case, the P polarization component and the S polarization component of the light emitted from the light source 20 are diffused in the x-axis direction and the y-axis direction respectively by the optical element 10. Therefore, the light emitted from the light source 20 is controlled by the optical element 10 to have a circular light distribution. It should be noted that it is also possible to control the light distribution to have an elliptical shape by changing the magnitude of the high (High) voltage and the low (Low) voltage applied to each transparent electrode 120.

[0130] As described above, in the control of light distribution by the lighting device 1A according to the present embodiment, one frame is divided into a plurality of sub-frame periods SF. In each sub-frame period SF, the output channel of the switch circuit unit 320 is switched according to two voltage signals input from the signal generation circuit unit 310 to two pairs of voltage signal lines 330 (first voltage signal line 330-1 to fourth voltage signal line), and the two voltage signals are respectively input to two adjacent transparent electrodes 120. In this way, even if a plurality of pairs of voltage signal lines 330 are used to control light distribution, the number of voltage signal lines 330 can be reduced to be less than the number of transparent electrodes 120, and as a result, the number of DACs and AMPs can be reduced. Therefore, in the lighting device 1A, the control device 30A can be miniaturized and the manufacturing cost can be reduced.

[0131] <Third Embodiment>

[0132] Reference Fig. 9 , a lighting device 1B according to an embodiment of the present invention will be described. It should be noted that when the structure of the lighting device 1B is the same as that of the lighting device 1, the description of the structure of the lighting device 1B may be omitted.

[0133] Fig. 9 1 is a block diagram showing the structure of a lighting device 1B according to an embodiment of the present invention. Fig. 9 As shown, the lighting device 1B includes an optical element 10, a light source 20, a control device 30B and a power source 40. The control device 30B includes a signal generation circuit section 310B, a switch circuit section 320, a first voltage signal line 330-1, a second voltage signal line 330-2 and a timing control signal line 340.

[0134] The signal generation circuit section 310B includes a DAC. That is, a DAC is built into the signal generation circuit section 310B, and the voltage signal output from the signal generation circuit section 310B is a digital signal. Therefore, neither the first voltage signal line 330-1 nor the second voltage signal line 330-2 includes a DAC.

[0135] As described above, in the lighting device 1B according to the present embodiment, the first voltage signal line 330-1 and the second voltage signal line 330-2 do not include a DAC occupying a large area. Therefore, in the lighting device 1B, the number of DACs can be reduced, and as a result, the manufacturing cost can be reduced.

[0136] Those skilled in the art can make various changes and modifications within the scope of the present invention, and it should be understood that these changes and modifications also belong to the scope of the present invention. For example, structures obtained by adding, deleting or changing the design of the above-mentioned embodiments by those skilled in the art, or structures obtained by adding, omitting or changing the conditions of the processes, as long as they have the gist of the present invention, are included in the scope of the present invention.

[0137] In addition, other effects brought about by each embodiment are clear from the description of this specification, or can be appropriately thought of by a person skilled in the art, and it is naturally understood that they are brought about by the present invention.

[0138] Description of Reference Numerals

[0139] 1, 1A, 1B: lighting device; 10: optical element; 20: light source; 30, 30A, 30B: control device; 40: power supply; 100: liquid crystal unit; 110: substrate; 120: transparent electrode; 121: connecting pad; 122: terminal; 130: orientation film; 140: sealing material; 150: liquid crystal layer; 160: optical elastic resin layer; 170: flexible printed substrate (FPCs); 310, 310B: signal generating circuit unit; 320, 320A: switching circuit unit, 330: voltage signal line; 331: digital analog conversion circuit (DAC); 332: amplifier circuit (AMP); 340: timing control signal line; 1000-1: first light; 1000-2: second light; CH: output channel; SF: subframe period.

Claims

1. A lighting device, comprising: light source; an optical element including a first liquid crystal cell and a second liquid crystal cell, the first liquid crystal cell and the second liquid crystal cell transmitting light emitted from the light source in a diffuse and variable manner; and a control device connected to the optical element and controlling the optical element, The first liquid crystal unit and the second liquid crystal unit respectively include: A first substrate, alternately provided with first transparent electrodes and second transparent electrodes extending along a first direction; a second substrate having third transparent electrodes and fourth transparent electrodes alternately disposed thereon extending along a second direction, the second direction intersecting the first direction; and A liquid crystal layer between the first substrate and the second substrate, The control device comprises: a switch circuit unit, comprising a first output channel, a second output channel, a third output channel, and a fourth output channel, wherein the first output channel is electrically connected to the first transparent electrode of the first liquid crystal unit, the second output channel is electrically connected to the second transparent electrode of the first liquid crystal unit, the third output channel is electrically connected to the third transparent electrode of the first liquid crystal unit, and the fourth output channel is electrically connected to the fourth transparent electrode of the first liquid crystal unit; a signal generating circuit that generates a plurality of voltage signals, wherein the plurality of voltage signals are input to the first transparent electrode, the second transparent electrode, the third transparent electrode, and the fourth transparent electrode of each of the first liquid crystal unit and the second liquid crystal unit; and The first voltage signal line and the second voltage signal line are connected to the switch circuit unit and the signal generation circuit unit, and are used to transmit one of the generated voltage signals respectively. One frame period includes a first subframe period and a second subframe period. During the first subframe period, the switch circuit unit is driven to connect the first voltage signal line to the first output channel and to connect the second voltage signal line to the second output channel. During the second subframe period, the switch circuit section is driven so that the first voltage signal line is electrically connected to the third output channel and the second voltage signal line is electrically connected to the fourth output channel.

2. The lighting device according to claim 1, wherein: During the first subframe, the third output channel and the fourth output channel are in a high impedance state. During the second subframe period, the first output channel and the second output channel are in a high impedance state.

3. The lighting device according to claim 1, wherein: The switch circuit unit further includes a fifth output channel, a sixth output channel, a seventh output channel, and an eighth output channel, wherein the fifth output channel is electrically connected to the first transparent electrode of the second liquid crystal unit, the sixth output channel is electrically connected to the second transparent electrode of the second liquid crystal unit, the seventh output channel is electrically connected to the third transparent electrode of the second liquid crystal unit, and the eighth output channel is electrically connected to the fourth transparent electrode of the second liquid crystal unit. The one frame period also includes a third subframe period and a fourth subframe period. During the third subframe period, the switch circuit unit is driven to connect the first voltage signal line to the fifth output channel and to connect the second voltage signal line to the sixth output channel. During the fourth subframe period, the switch circuit section is driven so that the first voltage signal line is electrically connected to the seventh output channel and the second voltage signal line is electrically connected to the eighth output channel.

4. The lighting device according to claim 3, wherein: During the third subframe, the first output channel, the second output channel, the third output channel, the fourth output channel, the seventh output channel, and the eighth output channel are in a high impedance state. During the fourth subframe period, the first output channel, the second output channel, the third output channel, the fourth output channel, the fifth output channel, and the sixth output channel are in a high impedance state.

5. The lighting device according to any one of claims 1 to 4, wherein: During the first subframe period, a phase of a first voltage signal input to the first transparent electrode of the first liquid crystal unit is opposite to a phase of a second voltage signal input to the second transparent electrode of the first liquid crystal unit.

6. The lighting device according to claim 5, wherein: During the second subframe period, a phase of a third voltage signal input to the third transparent electrode of the first liquid crystal unit is opposite to a phase of a fourth voltage signal input to the fourth transparent electrode of the first liquid crystal unit.

7. The lighting device according to claim 5, wherein: During the second subframe period, a phase of a third voltage signal input to the third transparent electrode of the first liquid crystal unit is the same as a phase of a fourth voltage signal input to the fourth transparent electrode of the first liquid crystal unit.

8. A lighting device, comprising: light source; An optical element including a first liquid crystal cell and a second liquid crystal cell, wherein the first liquid crystal cell and the second liquid crystal cell diffuse and variably transmit light emitted from the light source; as well as a control device connected to the optical element and controlling the optical element, The first liquid crystal unit and the second liquid crystal unit respectively include: A first substrate, alternately provided with first transparent electrodes and second transparent electrodes extending along a first direction; a second substrate having third transparent electrodes and fourth transparent electrodes alternately disposed thereon extending along a second direction, the second direction intersecting the first direction; and A liquid crystal layer between the first substrate and the second substrate, The control device comprises: a switch circuit portion, comprising a first output channel, a second output channel, a third output channel, a fourth output channel, a fifth output channel, a sixth output channel, a seventh output channel, and an eighth output channel, wherein the first output channel is electrically connected to the first transparent electrode of the first liquid crystal unit, the second output channel is electrically connected to the second transparent electrode of the first liquid crystal unit, the third output channel is electrically connected to the third transparent electrode of the first liquid crystal unit, the fourth output channel is electrically connected to the fourth transparent electrode of the first liquid crystal unit, the fifth output channel is electrically connected to the first transparent electrode of the second liquid crystal unit, the sixth output channel is electrically connected to the second transparent electrode of the second liquid crystal unit, the seventh output channel is electrically connected to the third transparent electrode of the second liquid crystal unit, and the eighth output channel is electrically connected to the fourth transparent electrode of the second liquid crystal unit; a signal generating circuit that generates a plurality of voltage signals, wherein the plurality of voltage signals are input to the first transparent electrode, the second transparent electrode, the third transparent electrode, and the fourth transparent electrode of each of the first liquid crystal unit and the second liquid crystal unit; and The first voltage signal line, the second voltage signal line, the third voltage signal line, and the fourth voltage signal line are connected to the switch circuit unit and the signal generation circuit unit, and are respectively used to transmit one of the plurality of voltage signals generated. One frame period includes a first subframe period and a second subframe period. During the first subframe, the switch circuit unit is driven to connect the first voltage signal line, the second voltage signal line, the third voltage signal line, and the fourth voltage signal line to the first output channel, the second output channel, the third output channel, and the fourth output channel, respectively. During the second subframe, the switch circuit unit is driven to connect the first voltage signal line, the second voltage signal line, the third voltage signal line, and the fourth voltage signal line to the fifth output channel, the sixth output channel, the seventh output channel, and the eighth output channel, respectively.

9. The lighting device according to claim 8, wherein: During the first subframe, the fifth output channel, the sixth output channel, the seventh output channel, and the eighth output channel are in a high impedance state. During the second subframe period, the first output channel, the second output channel, the third output channel, and the fourth output channel are in a high impedance state.

10. The lighting device according to claim 8 or 9, wherein: During the first subframe, a phase of a first voltage signal input to the first transparent electrode of the first liquid crystal unit is opposite to a phase of a second voltage signal input to the second transparent electrode of the first liquid crystal unit, and a phase of a third voltage signal input to the third transparent electrode of the first liquid crystal unit is opposite to a phase of a fourth voltage signal input to the fourth transparent electrode of the first liquid crystal unit.

11. The lighting device according to claim 8 or 9, wherein: During a first subframe, a phase of a first voltage signal input to the first transparent electrode of the first liquid crystal unit is opposite to a phase of a second voltage signal input to the second transparent electrode of the first liquid crystal unit, and a phase of a third voltage signal input to the third transparent electrode of the first liquid crystal unit is the same as a phase of a fourth voltage signal input to the fourth transparent electrode of the first liquid crystal unit.

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