Dimming device

Abstract

To provide a dimming device capable of suppressing a decrease in the illuminance of emitted light. [Solution] The dimming device comprises a panel unit in which a plurality of dimming panels are stacked in the Z direction, a light source, and a driver electrically connected to each of the plurality of dimming panels and controlling the voltage applied to each of the plurality of dimming panels. Each of the plurality of dimming panels provided in the panel unit has a first substrate on which electrodes are provided, a second substrate overlapping the first substrate in the Z direction and also provided with electrodes, and a liquid crystal layer filled between the first substrate and the second substrate, wherein if one of the voltages supplied to the electrodes provided on the first substrate or the voltage supplied to the electrodes provided on the second substrate is a predetermined maximum voltage, the other is a voltage less than the predetermined maximum voltage.

Description

Technical Field

[0001] The present disclosure relates to a dimming device.

Background Art

[0002] The dimming device described in Patent Document 1 includes a light source and a panel unit. The panel unit has a plurality of dimming panels laminated in the vertical direction. When incident light enters the dimming panel on the light source side in the panel unit, the light transmittance of the incident light is adjusted in the panel unit, and the adjusted transmitted light is emitted from the dimming panel on the side opposite to the light source.

[0003] Each of the plurality of dimming panels includes a lower substrate, a drive electrode on the lower substrate side, an upper substrate, a drive electrode on the upper substrate side, and a liquid crystal layer. When a voltage is applied to the drive electrode on the lower substrate side, a circular arc-shaped electric field with the same potential convex upward is generated, and when a voltage is applied to the drive electrode on the upper substrate side, a circular arc-shaped electric field with the same potential convex downward is generated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the voltages applied to the upper and lower drive electrodes are increased, the electric fields located on the upper side and the lower side respectively become larger. Therefore, in the middle portion in the thickness direction of the liquid crystal layer, the upper electric field and the lower electric field intersect. As a result, the alignment of the liquid crystal molecules arranged in the middle portion in the thickness direction of the liquid crystal layer is disturbed, causing unintended diffusion, and there is a possibility that the illuminance of the light emitted from the panel unit of the dimming device decreases.

[0006] The purpose of this disclosure is to provide a dimming device that can suppress a decrease in the illuminance of emitted light. [Means for solving the problem]

[0007] A dimming device according to one aspect of the present disclosure comprises a panel unit in which a plurality of dimming panels are stacked in a first direction, a light source positioned on one side of the panel unit in the first direction, and a driver electrically connected to each of the plurality of dimming panels and controlling the voltage applied to each of the plurality of dimming panels, wherein each of the plurality of dimming panels provided on the panel unit has a first substrate on which electrodes are provided, a second substrate overlapping the first substrate in the first direction and on which electrodes are provided, and a liquid crystal layer filled between the first substrate and the second substrate, wherein if one of the voltages supplied to the electrodes provided on the first substrate or the voltages supplied to the electrodes provided on the second substrate is a predetermined maximum voltage, the other is a voltage less than the predetermined maximum voltage.

[0008] Furthermore, a dimming device according to another aspect of the present disclosure comprises a panel unit in which a plurality of dimming panels are stacked in a first direction, a light source positioned on one side of the panel unit in the first direction, and a driver electrically connected to each of the plurality of dimming panels and controlling the voltage applied to each of the plurality of dimming panels, wherein each of the plurality of dimming panels provided in the panel unit comprises a first substrate on which electrodes are provided, a second substrate overlapping the first substrate in the first direction and also provided with electrodes, and a filling between the first substrate and the second substrate. The plurality of dimming panels comprises a liquid crystal layer and other dimming panels, wherein the one dimming panel has a voltage below the predetermined maximum voltage when one of the voltages supplied to an electrode provided on the first substrate or the voltage supplied to an electrode provided on the second substrate is a predetermined maximum voltage, and the other dimming panel has a voltage below the lower limit of the predetermined high voltage range when one of the voltages supplied to an electrode provided on the first substrate or the voltage supplied to an electrode provided on the second substrate is a voltage that falls within a predetermined high voltage range. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram of the dimming panel according to the first embodiment, viewed from above. [Figure 2] Figure 2 is a plan view of the first substrate according to the first embodiment. [Figure 3] Figure 3 is a plan view of the second substrate according to the first embodiment. [Figure 4] Figure 4 is a plan view of a dimming panel in which a second substrate is placed on top of a first substrate. [Figure 5] Figure 5 is a schematic diagram of the four dimming panels that constitute the dimming device according to the first embodiment. [Figure 6] Figure 6 is a schematic diagram showing the arrangement of the four dimming panels in the panel unit. [Figure 7] Figure 7 is a block diagram of the dimming device. [Figure 8] Figure 8 is a schematic perspective view of the dimming panel, showing the arrangement of the drive electrodes. [Figure 9] Figure 9 is a cross-sectional view of the dimming panel, showing the orientation state of liquid crystal molecules when no voltage is applied to the drive electrode on the first substrate side. [Figure 10] Figure 10 is a cross-sectional view of the dimming panel, showing the orientation state of liquid crystal molecules when a voltage is applied to the drive electrode on the first substrate side. [Figure 11] Figure 11 is a cross-sectional view of the dimming panel, showing the orientation state of liquid crystal molecules when a voltage is applied to the drive electrode on the second substrate side. [Figure 12] Figure 12 shows the voltage waveforms input to the drive electrodes of each dimming panel. [Figure 13] Figure 13 is a schematic diagram showing a cross-section of the dimming panel corresponding to Figure 10, illustrating an upwardly convex electric field when a voltage is applied to the drive electrode on the first substrate side. [Figure 14] Figure 14 is a schematic diagram showing a cross-section of the dimming panel corresponding to Figure 11, illustrating the downward-convex electric field when a voltage is applied to the drive electrode on the second substrate side. [Figure 15] FIG. 15 is a view of the dimming panel seen from above, and is a view showing the direction of the electric field in the central portion in the thickness direction of the liquid crystal layer by an arrow. [Figure 16] FIG. 16 is a view showing the voltage waveforms input to the drive electrodes of each dimming panel in the second embodiment. [Embodiments for Carrying Out the Invention]

[0010] Embodiments (embodiment modes) for implementing the present disclosure will be described in detail while referring to the drawings. The present disclosure is not limited by the content described in the following embodiments. Further, the constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be combined as appropriate.

[0011] Note that the disclosure is merely an example, and for those that can be easily conceived by those skilled in the art with appropriate modifications while maintaining the gist of the disclosure, they are naturally included in the scope of the present disclosure. In addition, the drawings are schematically shown in terms of the width, thickness, shape, etc. of each part compared to the actual aspect in order to make the description clearer, but it is merely an example and does not limit the interpretation of the present disclosure. Also, in this specification and each drawing, the same reference numerals are given to the same elements as those described above with respect to the already shown drawings, and detailed descriptions may be omitted as appropriate.

[0012] In the XYZ coordinates shown in the figures, the X direction is the left-right direction, and the X1 side is opposite to the X2 side. The X1 side is also referred to as the left side, and the X2 side is also referred to as the right side. The Y direction is the front-back direction, and the Y1 side is opposite to the Y2 side. The Y1 side is also referred to as the front side, and the Y2 side is also referred to as the back side. The Z direction is the up-down direction (stacking direction). The Z1 side is opposite to the Z2 side. The Z1 side is also referred to as the upper side, and the Z2 side is also referred to as the lower side. Also, the Z direction is also referred to as the first direction.

[0013] [First Embodiment] First, the dimming panel 1 according to the first embodiment will be described. FIG. 1 is a schematic view of the dimming panel according to the first embodiment as viewed from above.

[0014] As shown in FIG. 1, the dimming panel 1 includes a first substrate 2 and a second substrate 3 disposed on the upper side (Z1 side) of the first substrate 2. The dimming panel 1 is octagonal in plan view and has a first side 11, a second side 12, a third side 13, a fourth side 14, a fifth side 15, a sixth side 16, a seventh side 17, and an eighth side 18. In the present invention, the shape of the dimming panel 1 is not particularly limited, and polygons other than octagons, as well as circles and ellipses, are also included in the present invention.

[0015] The end portion 2c on the Y1 side of the first substrate 2 is exposed at a portion along the first side 11. A first terminal group 10 is provided at the end portion 2c.

[0016] The end portion 2d on the X1 side of the first substrate 2 is exposed at a portion along the second side 12. A second terminal group 20 is provided at the end portion 2d. The active area AA is circular in plan view.

[0017] Next, the wirings of the first substrate 2 and the second substrate 3 will be described. FIG. 2 is a plan view of the first substrate according to the first embodiment. FIG. 3 is a plan view of the second substrate according to the first embodiment. FIG. 4 is a plan view of the dimming panel with the second substrate stacked on the first substrate.

[0018] As shown in FIG. 2, wirings, drive electrodes, and connection portions are provided on the first substrate 2. The connection portion C1 of the first substrate 2 and the connection portion C3 of the second substrate 3 (see FIG. 3) are electrically connected via conductive beads not shown. Similarly, the connection portion C2 of the first substrate 2 and the connection portion C4 of the second substrate 3 (see FIG. 3) are electrically connected via conductive beads not shown.

[0019] The first substrate 2 is octagonal in plan view and has a first side 211, a second side 212, a third side 213, a fourth side 214, a fifth side 215, a sixth side 216, a seventh side 217, and an eighth side 218.

[0020] The first terminal group 10 includes a first terminal 101, a second terminal 102, a third terminal 103, and a fourth terminal 104. The first terminal 101, the second terminal 102, the third terminal 103, and the fourth terminal 104 are arranged in order in the X direction from the X1 side to the X2 side.

[0021] The second terminal group 20 includes a fifth terminal 201, a sixth terminal 202, a seventh terminal 203, and an eighth terminal 204. The fifth terminal 201, sixth terminal 202, seventh terminal 203, and eighth terminal 204 are arranged sequentially in the Y direction from the Y1 side to the Y2 side.

[0022] The first terminal 101 and the fifth terminal 201 are electrically connected via wiring 241. A connection point C1 is provided in the middle of wiring 241.

[0023] The second terminal 102 and the sixth terminal 202 are electrically connected via wires 243 and 245. Wire 243 has a branch point 244, and wire 246 extends from branch point 244 to end 247.

[0024] The third terminal 103 and the seventh terminal 203 are electrically connected via wiring 248. The fourth terminal 104 and the eighth terminal 204 are electrically connected via wirings 249 and 251. A connection part C2 is provided between wiring 249 and wiring 251.

[0025] Multiple drive electrodes (first drive electrodes) 261 are connected to wirings 243 and 246. Multiple drive electrodes (second drive electrodes) 262 are connected to wiring 248. Drive electrodes 261 are also referred to as first drive electrodes. Drive electrodes 262 are also referred to as second drive electrodes. Both drive electrodes 261 and 262 extend in the X direction. Specifically, drive electrodes 261 and 262 are bent in a V-shape that is convex toward the Y2 side. Drive electrodes 261 and 262 are arranged alternately in the Y direction. Thus, the electrodes provided on the first substrate 2 include drive electrodes 261 and drive electrodes 262 arranged adjacent to drive electrodes 261.

[0026] As shown in Figure 3, the second substrate 3 is provided with wiring, drive electrodes, and connection parts. The second substrate 3 is octagonal in plan view and has a first side 311, a second side 312, a third side 313, a fourth side 314, a fifth side 315, a sixth side 316, a seventh side 317, and an eighth side 318.

[0027] Connection C3 is connected to wiring 343. Connection C4 is connected to wiring 346. Wiring 343 extends along the first side 311, the third side 313, and the eighth side 318. Wiring 346 extends along the fourth side 314, the fifth side 315, and the sixth side 316.

[0028] Multiple drive electrodes (third drive electrodes) 361 are connected to wiring 343. Multiple drive electrodes (fourth drive electrodes) 362 are connected to wiring 346. Drive electrodes 361 are also referred to as third drive electrodes. Drive electrodes 362 are also referred to as fourth drive electrodes. Both drive electrodes 361 and 362 extend in the Y direction. Specifically, drive electrodes 361 and 362 are bent in a V-shape that is convex toward the X2 side. Drive electrodes 361 and 362 are arranged alternately in the X direction. Thus, the electrodes provided on the second substrate 3 include drive electrodes 361 and drive electrodes 362 arranged adjacent to drive electrodes 361.

[0029] As shown in Figure 4, in the dimming panel 1 in which the second substrate 3 of Figure 3 is superimposed on the first substrate 2 of Figure 2, the edges 2c and 2d of the first substrate 2 are exposed. When the second substrate 3 is superimposed on the first substrate 2, the first edge 311, the third edge 313, and the second edge 312 of the second substrate 3 are located inward (in the central part in a plan view) relative to the first edge 211, the third edge 213, and the second edge 212 of the first substrate 2. Thus, since the area of ​​the second substrate 3 is smaller than the area of ​​the first substrate 2, in Figure 4, the first terminal group 10 provided on edge 2c of the first substrate 2 and the second terminal group 20 provided on edge 2d are exposed. The drive electrodes 361 and 362 are arranged to intersect with the drive electrodes 261 and 262. The intersection angle between the drive electrodes 361 and 362 and the drive electrodes 261 and 262 is, for example, 80 degrees or more and 100 degrees or less.

[0030] Next, the configuration of the dimming device 100 according to the first embodiment will be briefly described. Figure 5 is a schematic diagram of the four dimming panels constituting the dimming device according to the first embodiment. Figure 6 is a schematic diagram showing the arrangement of the four dimming panels in the panel unit.

[0031] As shown in Figures 5 and 6, the dimming device 100 comprises a light source 630 and a panel unit 110. The light source 630 is located below (on the Z2 side) the panel unit 110. In the panel unit 110, the first dimming panel 1A, the second dimming panel 1B, the third dimming panel 1C, and the fourth dimming panel 1D are stacked in order from top to bottom. Note that the number of dimming panels 1 included in the dimming device 100 is not limited to four, but can be two or more.

[0032] As shown in Figure 6, the first dimming panel 1A comprises a first substrate S11 (first substrate 2) and a second substrate S12 (second substrate 3) laminated on the upper side (Z1 side) of the first substrate S11. The second dimming panel 1B comprises a first substrate S21 (first substrate 2) and a second substrate S22 (second substrate 3) laminated on the upper side (Z1 side) of the first substrate S21. The third dimming panel 1C comprises a first substrate S31 (first substrate 2) and a second substrate S32 (second substrate 3) laminated on the upper side (Z1 side) of the first substrate S31. The fourth dimming panel 1D comprises a first substrate S41 (first substrate 2) and a second substrate S42 (second substrate 3) laminated on the upper side (Z1 side) of the first substrate S41.

[0033] Furthermore, as shown in Figure 5, in the first dimming panel 1A, the first group of terminals 10 (see Figure 4) provided at the end 2c of the first substrate S11 (first substrate 2) is located on the Y1 side, and the flexible printed circuit board 41 is electrically connected to the first group of terminals 10.

[0034] As shown in Figures 5 and 6, the second dimming panel 1B is the first dimming panel 1A rotated 180 degrees clockwise in a plan view. Therefore, the first terminal group 10 is located on the Y2 side, and the flexible printed circuit board 41 is electrically connected to the first terminal group 10. The third dimming panel 1C is the first dimming panel 1A rotated 90 degrees clockwise in a plan view, so that the second terminal group 20 provided at the end 2d is located on the Y2 side, and the flexible printed circuit board 41 is electrically connected to the second terminal group 20. The fourth dimming panel 1D is the first dimming panel 1A rotated 270 degrees clockwise in a plan view, so that the second terminal group 20 provided at the end 2d is located on the Y1 side, and the flexible printed circuit board 41 is electrically connected to the second terminal group 20.

[0035] Next, a block diagram of the dimming device 100 will be described. Figure 7 is a block diagram of the dimming device. As shown in Figure 7, the dimming device 100 according to the first embodiment includes an electrode drive circuit 112, a memory circuit 113, and a processing circuit 114 as control blocks for controlling the panel unit 110. The processing circuit 114 is composed of a microcontroller for performing light distribution control and dimming control of the dimming device 100. The processing circuit 114 is a driver that is electrically connected to each of the multiple dimming panels 1 and controls the voltage applied to each of the multiple dimming panels 1.

[0036] Based on the processing results in the processing circuit 114, the electrode drive circuit 112 supplies voltage to each drive electrode 261, 262, 361, and 362 of each dimming panel 1 of the panel unit 110.

[0037] The memory circuit 113 includes, for example, internal memory implemented in the microcontroller that constitutes the processing circuit 114. Intermediate data of the processing in the processing circuit 114 is temporarily stored in the memory area of ​​the memory circuit 113.

[0038] Furthermore, the memory circuit 113 includes a setting circuit 1131. The setting circuit 1131 sets various setting items such as the frequency and phase of the voltage supplied to each drive electrode 261, 262, 361, and 362 of each dimming panel 1. The setting circuit 1131 is exemplified by a DIP switch (Dual In-line Package switch) that can set each setting item. In this case, the setting circuit 1131 is exemplified by a configuration that includes multiple two-state switch circuits, for example, "0" and "1".

[0039] Next, we will describe the operating modes for general light diffusion. Figure 8 is a schematic perspective view of a dimming panel, showing the arrangement of the drive electrodes. As shown in Figure 8, the dimming panel 1 comprises a first substrate 2, drive electrodes 261 and 262 provided on the first substrate 2, a second substrate 3, drive electrodes 361 and 362 provided on the second substrate 3, and a liquid crystal layer LC disposed between the first substrate 2 and the second substrate 3.

[0040] As shown in Figure 8, the driving electrodes 261 and 262 and the driving electrodes 361 and 362 are a pair of electrodes positioned with the liquid crystal layer LC in between.

[0041] Figure 9 is a cross-sectional view of the dimming panel, showing the orientation of liquid crystal molecules when no voltage is applied to the drive electrode on the first substrate side. Figure 10 is a cross-sectional view of the dimming panel, showing the orientation of liquid crystal molecules when a voltage is applied to the drive electrode on the first substrate side. Figure 11 is a cross-sectional view of the dimming panel, showing the orientation of liquid crystal molecules when a voltage is applied to the drive electrode on the second substrate side. Note that Figures 9 and 10 are views of the dimming panel from the direction of arrow 610 in Figure 8, and Figure 11 is a view of the dimming panel from the direction of arrow 620 in Figure 8.

[0042] As shown in Figure 9, a first alignment film AL11 is formed on the drive electrodes 261 and 262, and as shown in Figure 11, a second alignment film AL12 is formed on the drive electrodes 361 and 362. A liquid crystal layer LC is filled between the first substrate 2 and the second substrate 3. As shown in Figure 10, the central part of the liquid crystal layer LC in the Z direction is an intermediate layer LC1. The liquid crystal layer LC contains multiple liquid crystal molecules 60. Of the liquid crystal molecules 60, those arranged in the intermediate layer LC1 are referred to as liquid crystal molecules 60A.

[0043] Figure 9 shows that in the dimming panel 1, the orientation processing direction of the first orientation film AL11 and the orientation processing direction of the second orientation film AL12 are different. Specifically, the first orientation film AL11 is oriented in the Y direction, and the second orientation film AL12 is oriented in the X direction. Thus, the orientation direction of the first orientation film AL11 and the orientation direction of the second orientation film AL12 are approximately orthogonal when viewed from the Z direction. As a result, the initial light distribution direction on the first substrate 2 side is orthogonal (intersects) with the initial light distribution direction on the second substrate 3 side when viewed from the Z direction. The orientation processing can be either rubbing processing or optical orientation processing. Furthermore, the orientation direction of the orientation film can be set within a range of 90 degrees ± 10 degrees with respect to the extending direction of the drive electrode.

[0044] Since the orientation direction of the first orientation film AL11 and the orientation direction of the second orientation film AL12 are approximately orthogonal, the liquid crystal molecules 60 of the liquid crystal layer LC are oriented such that their long axis direction is twisted by 90 degrees from the first orientation film AL11 to the second orientation film AL12 when not subjected to an external electric field. Figure 9 shows the state in which no voltage is applied to the driving electrodes 261 and 262, so as shown in Figure 9, the liquid crystal molecules 60 are oriented with their long axis direction twisted by 90 degrees from the first orientation film AL11 to the second orientation film AL12.

[0045] In detail, the initial orientation direction of the liquid crystal molecules 60 in the liquid crystal layer LC (the orientation along the long axis of the liquid crystal molecules) gradually rotates as you move from the first substrate 2 side to the second substrate 3 side, eventually rotating by 90 degrees. The liquid crystal molecules, which were oriented in this initial orientation direction, are rotated from their initial orientation direction according to the direction of the electric field generated between adjacent electrodes on each substrate, and this results in a refractive index distribution of light in the liquid crystal layer LC.

[0046] Figure 9 shows an example where, for example, a positive-type twisted nematic liquid crystal (TN liquid crystal) is used as the liquid crystal layer LC, and the long axis of the liquid crystal molecules 60 is oriented in the same direction as the orientation direction of the alignment film. Preferably, the liquid crystal layer LC contains a chiral agent that imparts twist to the liquid crystal molecules 60.

[0047] For example, when a voltage is applied to the drive electrodes 261 and 262 that alternates between a low-level voltage and a high-level voltage periodically, an electric field EF10 (shown by the dashed line) is generated between the drive electrodes 261 and 262, as shown in Figure 10. As shown in Figure 10, the orientation direction of the liquid crystal molecules 60 on the first substrate 2 changes due to the influence of the electric field. For example, the orientation of the liquid crystal molecules 60 on the first substrate 2 changes so that their long axis is parallel to the direction of the electric field.

[0048] It is known that the refractive index of liquid crystals changes depending on their orientation. As shown in Figure 9, in the OFF state where no electric field acts on the liquid crystal layer LC, the long axis of the liquid crystal molecules 60 is oriented horizontally to the surface of the substrate, and is oriented with a 90-degree twist from the first substrate 2 side to the second substrate 3 side. In this orientation state, the liquid crystal layer LC has a nearly uniform refractive index distribution. Therefore, although the S wave and the P wave perpendicular to the S wave of light incident on the dimming panel 1 rotate under the influence of the initial orientation of the liquid crystal molecules 60, they are transmitted through the liquid crystal layer LC in the Z direction with almost no refraction (or scattering). Optical rotation refers to the change in the direction of polarization of the polarization component as it passes through the liquid crystal layer LC. Specifically, it means that the P-polarized component (P wave) changes to the S-polarized component (S wave), and the S-polarized component (S wave) changes to the P-polarized component (P wave) as it passes through the liquid crystal layer LC.

[0049] On the other hand, as shown in Figure 10, in the ON state where a voltage is applied to the driving electrodes 261 and 262 and an electric field EF10 is formed, if the liquid crystal layer LC has positive dielectric anisotropy, the liquid crystal molecules 60 will orient themselves so that their long axes are aligned with the electric field EF10. As a result, as shown in Figure 10, the liquid crystal layer LC will have regions where the liquid crystal molecules 60 stand almost vertically above the driving electrodes 261 and 262, regions where they are orienting diagonally along the distribution of the electric field EF10 between the driving electrodes 261 and 262, and regions where the initial orientation state is maintained away from the driving electrodes 261 and 262.

[0050] As shown in Figure 10, between the driving electrodes 261 and 262, the long axis of the liquid crystal molecules 60 is oriented in an upwardly convex arc shape along the direction in which the electric field EF10 is generated. Therefore, when considering the liquid crystal on the first substrate 2 side as a whole, the liquid crystal molecules 60 are oriented in an upwardly convex arc shape between the driving electrodes 261 and 262. As a result, a dielectric constant distribution is formed within the liquid crystal layer LC, and the incident light (polarization component parallel to the initial orientation direction of the liquid crystal molecules 60) diffuses radially.

[0051] Furthermore, as shown in Figure 11, on the second substrate 3 side, a voltage is applied to the driving electrodes 361 and 362. For example, in the ON state, when a downwardly convex arc-shaped electric field EF20 of the same potential is formed, if the liquid crystal layer LC has positive dielectric anisotropy, the liquid crystal molecules 60 will be oriented so that their long axes are aligned with the electric field EF20. That is, between the electrodes of the driving electrodes 361 and 362, the long axes of the liquid crystal molecules 60 are oriented in a downwardly convex arc shape along the direction in which the electric field EF20 is generated. Consequently, the driving electrodes 361 and 362 cause the polarization component of the incident light parallel to the initial orientation direction of the liquid crystal molecules 60 on the second substrate 3 side to diffuse radially. That is, the polarization diffused on the first substrate 2 side and the polarization diffused on the second substrate 3 side rotate and change polarization direction when passing through the liquid crystal layer LC, so the same polarization is diffused.

[0052] Next, the voltages applied to the drive electrodes on the first substrate and the second substrate will be explained. Figure 12 shows the voltage waveforms input to the drive electrodes of each dimming panel. Figure 13 is a schematic diagram showing a cross-section of the dimming panel corresponding to Figure 10, and shows an upwardly convex electric field when a voltage is applied to the drive electrode on the first substrate. Figure 14 is a schematic diagram showing a cross-section of the dimming panel corresponding to Figure 11, and shows a downwardly convex electric field when a voltage is applied to the drive electrode on the second substrate.

[0053] As shown in Figure 12, each of the four stacked dimming panels 1 has either a voltage applied to the drive electrodes 261 and 262 on the first substrate 2 side or a voltage applied to the drive electrodes 361 and 362 on the second substrate 3 side that is a "predetermined maximum voltage," and the other voltage that is a "voltage less than the predetermined maximum voltage." In detail, in the first embodiment, a(V) is the "predetermined maximum voltage," and b(V) is the "voltage less than the predetermined maximum voltage." A detailed explanation follows below.

[0054] As shown in Figure 12, in the first dimming panel 1A, a voltage of voltage waveform C is applied to the drive electrode 261 on the first substrate S11 side, and a voltage of voltage waveform D is applied to the drive electrode 262. The high-level voltage in voltage waveforms C and D is (+bV), and the low-level voltage is (-bV). That is, pulse voltages with the same amplitude and opposite signs for the same period are applied to the drive electrode 261 and drive electrode 262 on the first substrate S11 side. In addition, the P-wave of incident light is diffused in the longitudinal direction at the drive electrode 261 and drive electrode 262 on the first substrate S11 side.

[0055] Furthermore, in the first dimming panel 1A, the voltage of voltage waveform A is applied to the drive electrode 361 on the second substrate S12 side, and the voltage of voltage waveform B is applied to the drive electrode 362. The high-level voltage in voltage waveforms A and B is (+aV), and the low-level voltage is (-aV). a(V) is greater than b(V). a(V) is, for example, 7.5V, and b(V) is, for example, 3V. In this way, pulse voltages with the same amplitude and opposite signs for the same period are applied to the drive electrode 361 and drive electrode 362 on the second substrate S12 side. Also, in the drive electrode 361 and drive electrode 362 on the second substrate S12 side, the P-wave when light is incident is diffused laterally. As mentioned above, aV is the predetermined maximum voltage (7.5V), and bV is a voltage less than the predetermined maximum voltage (3V). Therefore, in the first dimming panel 1A, the voltage applied to the drive electrodes 361 and 362 on the second substrate S12 side is the "predetermined maximum voltage". The "predetermined maximum voltage" is, for example, aV (7.5V), but other voltages may be appropriately adopted depending on various conditions such as the performance of the panel.

[0056] As shown in Figure 12, in the second dimming panel 1B, voltage waveform A is applied to the drive electrode 261 on the first substrate S21 side, and voltage waveform B is applied to the drive electrode 262. The high-level voltage in voltage waveforms A and B is (+aV), and the low-level voltage is (-aV). In addition, the S-waves of incident light are diffused in the longitudinal direction at the drive electrodes 261 and 262 on the first substrate S21 side.

[0057] Furthermore, in the second dimming panel 1B, the voltage of voltage waveform C is applied to the drive electrode 361 on the second substrate S22 side, and the voltage of voltage waveform D is applied to the drive electrode 362. The high-level voltage in voltage waveforms C and D is (+bV), and the low-level voltage is (-bV). Also, at the drive electrodes 361 and 362 on the second substrate S22 side, the S-waves when light is incident are diffused laterally. In the second dimming panel 1B, the voltage applied to the drive electrodes 261 and 262 on the first substrate S21 side is the "predetermined maximum voltage".

[0058] As shown in Figure 12, in the third dimming panel 1C, voltage waveform A is applied to the drive electrode 261 on the first substrate S31 side, and voltage waveform B is applied to the drive electrode 262. The high-level voltage in voltage waveforms A and B is (+aV), and the low-level voltage is (-aV). In addition, the S-waves of incident light are diffused laterally at the drive electrodes 261 and 262 on the first substrate S31 side.

[0059] Furthermore, in the third dimming panel 1C, the voltage of voltage waveform C is applied to the drive electrode 361 on the second substrate S32 side, and the voltage of voltage waveform D is applied to the drive electrode 362. The high-level voltage in voltage waveforms C and D is (+bV), and the low-level voltage is (-bV). Also, at the drive electrodes 361 and 362 on the second substrate S32 side, the S-wave when light is incident is diffused in the longitudinal direction. In the third dimming panel 1C, the voltage applied to the drive electrodes 261 and 262 on the first substrate S31 side is the "predetermined maximum voltage".

[0060] As shown in Figure 12, in the fourth dimming panel 1D, a voltage of voltage waveform C is applied to the drive electrode 261 on the first substrate S41 side, and a voltage of voltage waveform D is applied to the drive electrode 262. The high-level voltages in voltage waveforms C and D are (+bV), and the low-level voltages are (-bV). In addition, the P-waves of incident light are diffused laterally at the drive electrodes 261 and 262 on the first substrate S41 side.

[0061] Furthermore, in the fourth dimming panel 1D, the voltage of voltage waveform A is applied to the drive electrode 361 on the second substrate S42 side, and the voltage of voltage waveform B is applied to the drive electrode 362. The high-level voltage in voltage waveforms A and B is (+aV), and the low-level voltage is (-aV). Also, at the drive electrodes 361 and 362 on the second substrate S42 side, the P-waves when light is incident are diffused in the longitudinal direction. In the fourth dimming panel 1D, the voltage applied to the drive electrodes 361 and 362 on the second substrate S42 side is the "predetermined maximum voltage".

[0062] Here, we will explain the magnitude of the electric field. As shown in Figure 13, the electric field acting on the driving electrode 261 and the driving electrode 262 is the electric field EF10 shown by the dashed line when the applied voltage is a (V), and the electric field EF10a shown by the solid line when the applied voltage is b (V).

[0063] As shown in Figure 14, the electric field acting on the drive electrode 361 and the drive electrode 362 is the electric field EF20 shown by the dashed line when the applied voltage is a (V), and the electric field EF20a shown by the solid line when the applied voltage is b (V).

[0064] To summarize, using the magnitude of the electric field when the applied voltage is a(v) as a reference, in the first dimming panel 1A, the magnitude of the electric field on the first substrate S11 side is a smaller electric field EF10a than the reference, and the magnitude of the electric field on the second substrate S12 side is the same electric field EF20 as the reference.

[0065] Similarly, in the second dimming panel 1B, using the magnitude of the electric field when the applied voltage is a(v) as a reference, the magnitude of the electric field on the first substrate S21 side is the same as the reference electric field EF10, and the magnitude of the electric field on the second substrate S22 side is a smaller electric field EF20a than the reference.

[0066] In the third dimming panel 1C, using the magnitude of the electric field when the applied voltage is a(v) as a reference, the magnitude of the electric field on the first substrate S31 side is the same as the reference electric field EF10, and the magnitude of the electric field on the second substrate S32 side is a smaller electric field EF20a than the reference.

[0067] In the fourth dimming panel 1D, using the magnitude of the electric field when the applied voltage is a(v) as a reference, the magnitude of the electric field on the first substrate S41 side is a smaller electric field EF10a, while the magnitude of the electric field on the second substrate S42 side is the same electric field EF20 as the reference.

[0068] Figure 15 is a view of the dimming panel from above, and the direction of the electric field in the center of the thickness direction of the liquid crystal layer is indicated by an arrow. When the voltage applied to the drive electrodes 261 and 262 is a predetermined maximum voltage a(V), the region where the convex arc-shaped electric field EF10 of the same potential extends to the Z1 side (upper side), as shown in Figure 13, reaches the region of the intermediate layer LC1. Also, when the voltage applied to the drive electrodes 361 and 362 is a predetermined maximum voltage a(V), the region where the convex arc-shaped electric field EF20 extends to the Z2 side (lower side), as shown in Figure 14, reaches the region of the intermediate layer LC1. That is, when both the voltage applied to the drive electrodes 261 and 262 and the voltage applied to the drive electrodes 361 and 362 are at their maximum voltage a(V), the region affected by the electric field EF10 from the drive electrodes 261 and 262 and the region affected by the electric field EF20 from the drive electrodes 361 and 362 intersect in the region of the intermediate layer LC1. As a result, as shown by the dashed line in Figure 15, an electric field acts in the intermediate layer LC1 along an oblique direction that intersects both the X and Y directions.

[0069] In contrast, as explained in Figure 12, if one of the electric fields acting on the first substrate 2 side and the electric field acting on the second substrate 3 side is at a predetermined maximum voltage (aV) and the other is at a voltage less than the predetermined maximum voltage (bV), then the region affected by the electric field EF10 and the region affected by the electric field EF20a are less likely to intersect in the region of the intermediate layer LC1. Therefore, as shown by the solid arrows in Figure 15, in the first embodiment, in the region of the intermediate layer LC1, for example, the electric field acts along a direction substantially perpendicular to the driving electrode 261 and the driving electrode 262.

[0070] In the dimming device 100 according to the first embodiment, the vertical diffusion and the horizontal diffusion are of the same magnitude, so the light output from the panel unit spreads in both the vertical and horizontal directions, resulting in a so-called vertical and horizontal diffusion shape.

[0071] As described above, the dimming device 100 according to the first embodiment comprises a panel unit 110, a light source 630, and a processing circuit 114 (driver). Each of the plurality of dimming panels has a first substrate 2, a second substrate 3, and a liquid crystal layer 4. If one of the voltages supplied to the electrodes provided on the first substrate 2 or the voltage supplied to the electrodes provided on the second substrate 3 is a predetermined maximum voltage (aV), the other is a voltage (bV) less than the predetermined maximum voltage.

[0072] As mentioned above, in the dimming device described in Patent Document 1, when the voltage applied to the upper and lower drive electrodes is increased, the upper and lower electric fields intersect in the middle portion of the liquid crystal layer in the thickness direction. As a result, the orientation of the liquid crystal molecules located in the middle portion of the liquid crystal layer in the thickness direction becomes disordered, causing unintended diffusion, which may reduce the illuminance of the light emitted from the panel unit of the dimming device.

[0073] In contrast, in the first embodiment, when one of the voltages supplied to the electrodes provided on the first substrate 2 or the voltage supplied to the electrodes provided on the second substrate 3 is a predetermined maximum voltage (aV), the other is a voltage less than the predetermined maximum voltage (bV). Therefore, the intersection of the upper electric field and the lower electric field in the intermediate layer LC1 in the thickness direction of the liquid crystal layer LC is further suppressed, making it less likely for the orientation of the liquid crystal molecules 60A arranged in the intermediate layer LC1 to be disturbed, and unintended diffusion is suppressed. Consequently, the decrease in the illuminance of the light emitted from the panel unit 110 of the dimming device 100 is suppressed.

[0074] Furthermore, the electrodes provided on the first substrate 2 include a first drive electrode 261 and a second drive electrode 262 positioned adjacent to the first drive electrode 261, and the electrodes provided on the second substrate 3 include a third drive electrode 361 and a fourth drive electrode 362 positioned adjacent to the third drive electrode 361.

[0075] Therefore, it becomes easy to apply pulse voltages to the first drive electrode 261 and the second drive electrode 262, and to the third drive electrode 361 and the fourth drive electrode 362, which have the same amplitude and opposite polarity during the same period.

[0076] [Second Embodiment] Next, the second embodiment will be described. In the first embodiment, there were two voltage levels (aV and bV) applied to the drive electrodes, but in the second embodiment, there are four levels (aV, bV, cV, and dV). Figure 16 is a diagram showing the voltage waveforms input to the drive electrodes of each dimming panel in the second embodiment. In the second embodiment, the four dimming panels consist of one dimming panel and the other dimming panels. In the one dimming panel, if one of the voltages supplied to the electrodes provided on the first substrate 2 or the voltage supplied to the electrodes provided on the second substrate 3 is a "predetermined maximum voltage", the other is a "voltage less than the predetermined maximum voltage". In the other dimming panels, if one of the voltages supplied to the electrodes provided on the first substrate 2 or the voltage supplied to the electrodes provided on the second substrate 3 is a "voltage that falls within a predetermined high voltage range", the other is a "voltage lower than the lower limit of the predetermined high voltage range". More specifically, in the second embodiment, "one dimming panel" refers to the first dimming panel 1A and the third dimming panel 1C, and "other dimming panels" refers to the second dimming panel 1B and the fourth dimming panel 1D. "A predetermined maximum voltage" is, for example, aV (7.5V). Also, "a predetermined high voltage range" is, for example, cV or more and aV or less. aV is, for example, 7.5V, bV is, for example, 3V, cV is, for example, 5V, and dV is, for example, 1V. Therefore, "a predetermined high voltage range" is, for example, 5V or more and 7.5V or less. The following will mainly describe the differences from the first embodiment.

[0077] As shown in Figure 16, in the first dimming panel 1A, the voltage applied to the drive electrodes 261 and 262 on the first substrate 2 side and the voltage applied to the drive electrodes 361 and 362 on the second substrate 3 side are the same as in the first embodiment.

[0078] Specifically, in the first dimming panel 1A, a voltage of voltage waveform C is applied to the drive electrode 261 on the first substrate S11 side, and a voltage of voltage waveform D is applied to the drive electrode 262. The high-level voltage in voltage waveforms C and D is (+bV), and the low-level voltage is (-bV). Also in the first dimming panel 1A, a voltage of voltage waveform A is applied to the drive electrode 361 on the second substrate S12 side, and a voltage of voltage waveform B is applied to the drive electrode 362. The high-level voltage in voltage waveforms A and B is (+aV), and the low-level voltage is (-aV). aV is the "predetermined maximum voltage". Since bV is smaller than aV, bV is the "voltage less than the predetermined maximum voltage".

[0079] In the second dimming panel 1B, a voltage waveform E is applied to the drive electrode 261 on the first substrate S21 side, and a voltage waveform F is applied to the drive electrode 262. The high-level voltage in voltage waveforms E and F is (+cV), and the low-level voltage is (-cV). That is, pulse voltages with the same amplitude and opposite signs for the same period are applied to the drive electrode 261 and drive electrode 262 on the first substrate S21 side.

[0080] Furthermore, in the second dimming panel 1B, a voltage of voltage waveform G is applied to the drive electrode 361 on the second substrate S22 side, and a voltage of voltage waveform H is applied to the drive electrode 362. The high-level voltage in voltage waveforms G and H is (+dV), and the low-level voltage is (-dV). That is, pulse voltages with the same amplitude and opposite signs for the same period are applied to the drive electrode 361 and drive electrode 362 on the second substrate S22 side. Also, cV is greater than dV, and aV is greater than cV. Therefore, in the second dimming panel 1B according to the second embodiment, cV (5V) is a "voltage corresponding to a predetermined high-voltage range". Also, dV (1V) is a "voltage lower than the lower limit of the predetermined high-voltage range".

[0081] In the third dimming panel 1C, a voltage of voltage waveform A is applied to the drive electrode 261 on the first substrate S31 side, and a voltage of voltage waveform B is applied to the drive electrode 262. In addition, a voltage of voltage waveform C is applied to the drive electrode 361 on the second substrate S32 side, and a voltage of voltage waveform D is applied to the drive electrode 362. Therefore, in the third dimming panel 1C according to the second embodiment, aV (7.5V) is the "predetermined maximum voltage," and bV (3V) is the "voltage below the predetermined maximum voltage."

[0082] In the fourth dimming panel 1D, a voltage of voltage waveform G is applied to the drive electrode 261 on the first substrate S41 side, and a voltage of voltage waveform H is applied to the drive electrode 262. In addition, a voltage of voltage waveform E is applied to the drive electrode 361 on the second substrate S42 side, and a voltage of voltage waveform F is applied to the drive electrode 362. Therefore, in the fourth dimming panel 1D according to the second embodiment, cV (5V) is a voltage that falls within a predetermined high voltage range. Also, dV (1V) is a voltage lower than the lower limit of the predetermined high voltage range.

[0083] In the dimming device according to the second embodiment, since aV is greater than cV, the lateral diffusion is greater than the vertical diffusion. Therefore, the light output from the panel unit 110 is an elongated ellipse in the lateral direction. In the second embodiment, aV is greater than bV, cV is greater than dV, and aV is greater than cV.

[0084] As a variation, for example, in the fourth dimming panel 1D, a voltage of voltage waveform G may be applied to the drive electrode 261 on the first substrate S41 side, a voltage of voltage waveform H may be applied to the drive electrode 262, and a voltage of voltage waveform G may be applied to the drive electrode 361 on the second substrate S42 side, and a voltage of voltage waveform H may be applied to the drive electrode 362. With this, as shown in Figure 13, the region affected by the electric field of the drive electrode on the first substrate side and the region affected by the electric field of the drive electrode on the second substrate side become even less likely to intersect in the region of the intermediate layer LC1.

[0085] As described above, in the second embodiment, the dimming panels consist of "one dimming panel" and "other dimming panels". In the one dimming panel, if one of the voltages supplied to the electrodes provided on the first substrate 2 or the voltage supplied to the electrodes provided on the second substrate 3 is "a predetermined maximum voltage (aV)", the other is "a voltage less than the predetermined maximum voltage (bV)". In the other dimming panel, if one of the voltages supplied to the electrodes provided on the first substrate 2 or the voltage supplied to the electrodes provided on the second substrate 3 is "a voltage that falls within a predetermined high voltage range (cV)", the other is "a voltage lower than the lower limit of the predetermined high voltage range (dV)". Therefore, in the second embodiment as well, the intersection of the upper electric field and the lower electric field in the intermediate layer LC1 in the thickness direction of the liquid crystal layer LC is further suppressed, so that the orientation disorder of the liquid crystal molecules 60A arranged in the intermediate layer LC1 is less likely to occur, and unintended diffusion is suppressed. Consequently, the decrease in the illuminance of the light emitted from the panel unit of the dimming device is suppressed. [Explanation of Symbols]

[0086] 1. Dimming panel 1A First dimming panel (dimming panel) (first dimming panel) 1B Second dimming panel (dimming panel) (other dimming panels) 1C Third dimming panel (dimming panel) (first dimming panel) 1D Fourth dimming panel (dimming panel) (other dimming panels) 2. First substrate 3. Second board 100 dimmers 110 Panel Unit 114 Processing Circuit (Driver) 261 Driving electrode (first driving electrode) 262 Drive electrode (second drive electrode) 361 Drive electrode (3rd drive electrode) 362 Drive electrode (4th drive electrode) 630 light source LC liquid crystal layer LC1 middle layer

Claims

1. The system comprises a panel unit in which multiple dimming panels are stacked in a first direction, a light source positioned on one side of the panel unit in the first direction, and a driver electrically connected to each of the multiple dimming panels and controlling the voltage applied to each of the multiple dimming panels, Each of the plurality of dimming panels provided in the panel unit is, A first substrate on which electrodes are provided, The first substrate and the second substrate which overlaps in the first direction and has electrodes provided thereon, The device comprises a liquid crystal layer filled between the first substrate and the second substrate, If one of the voltages supplied to the electrodes provided on the first substrate or the voltage supplied to the electrodes provided on the second substrate is a predetermined maximum voltage, then the other voltage is less than the predetermined maximum voltage. Dimming device.

2. The system comprises a panel unit in which multiple dimming panels are stacked in a first direction, a light source positioned on one side of the panel unit in the first direction, and a driver electrically connected to each of the multiple dimming panels and controlling the voltage applied to each of the multiple dimming panels, Each of the plurality of dimming panels provided in the panel unit is, A first substrate on which electrodes are provided, The first substrate and the second substrate which overlaps in the first direction and has electrodes provided thereon, The device comprises a liquid crystal layer filled between the first substrate and the second substrate, The aforementioned plurality of dimming panels consist of one dimming panel and other dimming panels. The first dimming panel is configured such that when one of the voltages supplied to the electrodes provided on the first substrate or the voltage supplied to the electrodes provided on the second substrate is a predetermined maximum voltage, the other voltage is less than the predetermined maximum voltage. In the aforementioned other dimming panel, if one of the voltages supplied to the electrodes provided on the first substrate or the voltage supplied to the electrodes provided on the second substrate falls within a predetermined high-voltage range, the other voltage is lower than the lower limit of the predetermined high-voltage range. Dimming device.

3. The electrode provided on the first substrate comprises a first drive electrode and a second drive electrode positioned adjacent to the first drive electrode. The electrode provided on the second substrate comprises a third drive electrode and a fourth drive electrode positioned adjacent to the third drive electrode. A dimming device according to claim 1 or 2.

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