WO2017170688A1 - Light control system, light control device, light control film, method for driving light control film, and vehicle - Google Patents

Abstract

According to the present invention, in relation to a light control film using liquid crystals, it is possible to prevent uneven luminance that occurs temporarily when a transmittance is variable. Provided are the following: a light control film 10 for controlling transmitted light by orienting, by a VA scheme, liquid crystals of liquid crystal cells 14 sandwiched between linear polarizing plates 12, 13; and a light control device 3 having a drive power source generation unit 5 for outputting a square wave signal to the light control film 10. The light control device 3 varies the transmittance of the light control film 10 by varying the amplitude of the square wave signal in response to operation of operation pieces 2U, 2D; when the amplitude of the square wave signal is to be increased, the amplitude of the square wave signal is increased gradually.

Description

Light control system, light control device, light control film, method of driving light control film, and vehicle

The present invention relates to a light control system, a light control device, a light control film, a method of driving the light control film, and a vehicle.

Conventionally, for example, various devices relating to a light control film that is attached to a window to control the transmission of external light have been proposed (Patent Documents 1 and 2).
One such light control film uses liquid crystal.
The light control film using the liquid crystal is prepared by sandwiching a liquid crystal material with a transparent film material having a transparent electrode and an alignment layer, and a liquid crystal cell between the linear polarizing plates.
As a result, in the light control film using this liquid crystal, the orientation of the liquid crystal can be changed by changing the electric field applied to the liquid crystal to block or transmit extraneous light, and further the amount of transmitted light can be changed. Control the transmission of extraneous light.

The light control film using this liquid crystal has the advantage of responding at high speed in principle as compared with a configuration using electrochromic or the like which is a similar configuration for controlling external light.

In addition, a liquid crystal display panel, which is one of image display panels, includes a liquid crystal cell sandwiched between a pair of glass plates made of transparent electrodes and alignment films, and the liquid crystal cell is sandwiched between linear polarizing plates. Configured. The liquid crystal display panel displays a desired image by changing the electric field applied to the liquid crystal in units of pixels by patterning the transparent electrode.

Like the liquid crystal display panel, the light control film is configured to control the transmitted light by controlling the orientation of the liquid crystal molecules, so that various driving methods proposed for the image display panel can be used. It is done.

Various driving methods proposed for liquid crystal display panels can be applied to driving the liquid crystal cell. Specifically, for example, a driving method such as a TN (Twisted Nematic) method, an IPS (In-Plane-Switching) method, or a VA (Virtual Alignment) method can be applied.

The TN system is a system in which the alignment of liquid crystal molecules is changed between a vertical direction and a horizontal twist direction by applying an electric field, and the amount of transmitted light is controlled using the optical rotation of light.
The IPS method is a method of controlling the amount of transmitted light by rotating aligned liquid crystal molecules in a horizontal (horizontal) direction with respect to a substrate.

The VA method can be configured by a normally black method in which a non-transmission state (light-shielding state) is obtained when no electric field is applied, and has a feature of a high light-shielding rate in this light-shielding state.
Thus, in the case of controlling the transmission of extraneous light by applying to a sunroof of a vehicle, it is conceivable to use a VA-type light control film.

The VA method is a method of controlling transmitted light by changing the alignment of liquid crystal molecules between vertical alignment and horizontal alignment. In general, when no electric field is applied, the liquid crystal is vertically aligned, whereby the liquid crystal layer is sandwiched between the vertical alignment layers to form a liquid crystal cell, and the liquid crystal material is horizontally aligned by applying an electric field.
Usually, when no electric field is applied, incident light is shielded by vertical alignment, and when an electric field is applied, incident light is transmitted by horizontal alignment.
In the VA mode, the liquid crystal molecules related to the vertical alignment are tilted by a slight angle (a pretilt angle of the liquid crystal molecules, which is about 0.5 degrees) in a specific direction. In the VA system, the long axis direction of the liquid crystal molecules is aligned horizontally with the direction related to the pretilt angle by this inclination, and the transmittance during light transmission is improved.

However, when the light control film was configured by the VA method and experimented, the speed of change from the light-shielding state to the light-transmitting state when an electric field was applied to increase the transmittance was different in each part of the light control film. It was found that uneven brightness occurred temporarily. Such luminance unevenness occurs temporarily when the transmittance is variable, but it significantly reduces the quality of the light control and impairs the advantage of the liquid crystal light control film responding at high speed.

Also, the light control film is used for blindfolding by being placed in a window, for example. In particular, the VA method can obtain a high light shielding effect. For this reason, the VA type light control film is used by being attached to a sunroof of a vehicle, for example.

However, when a VA-type light control film is used for a mobility product such as a vehicle, the molecules fluctuate due to vibration during traveling. For this reason, the direction in which the molecules fall is affected, and the response speed when changing the amount of transmitted light is deteriorated. Furthermore, there is a possibility that problems such as a distribution in the transmittance occur.

JP 03-47392 A Japanese Patent Laid-Open No. 08-184273

The present invention has been made in view of such a situation, and an object of the present invention is to prevent luminance unevenness that temporarily occurs when the transmittance is variable in a light control film using liquid crystal.
Another object of the present invention is to provide a light control system, a vehicle, and a method of driving a light control film that can reduce response speed degradation and non-uniform transmittance when used in a vehicle or the like. To do.

The present inventor has conducted intensive research to solve the above problems, and has come to the idea that the amplitude of the applied voltage is gradually increased, thus completing the present invention.

Specifically, the present invention provides the following.

(1) a light control film for controlling transmitted light by aligning liquid crystals of a liquid crystal cell sandwiched by linearly polarizing plates by a VA method;
A light control device having a drive power generation unit that outputs a rectangular wave signal to the light control film;
The light control device is:
By varying the amplitude of the rectangular wave signal in response to the operation of the operation element, the transmittance of the light control film is varied,
A dimming system that gradually increases the amplitude of the rectangular wave signal when increasing the amplitude of the rectangular wave signal.

According to (1), by gradually increasing the amplitude of the rectangular wave signal from the drive power supply (the amplitude of the applied voltage), it is possible to tilt the liquid crystal in a state where the directions of the major axes of the liquid crystal are aligned. As a result, it is possible to shorten the time until the tilted liquid crystal orientations are aligned, and to prevent uneven brightness that temporarily occurs when the transmittance is variable. Here, “gradually” means not only continuous increase but also stepwise increase.

(2) A dimming system in which the time for gradually increasing the amplitude of the rectangular wave signal in (1) is 3 seconds or less.

(3) In (1) or (2),
The light control device is:
A dimming system that gradually increases the amplitude of the rectangular wave signal by sequentially increasing the amplitude in a plurality of cycles of the rectangular wave signal.

According to (3), the luminance that is temporarily generated when the transmittance is variable by increasing the amplitude of the rectangular wave signal stepwise in a plurality of cycles or continuously in a plurality of cycles. Unevenness can be prevented.

(4) In (1) or (2),
The light control device is:
A dimming system that gradually increases the amplitude of the rectangular wave signal by gradually increasing the amplitude in each period of the rectangular wave signal by a time constant circuit.

According to (4), the amplitude of the rectangular wave signal can be gradually increased by dulling the rise and fall of each cycle by the time constant circuit, and the luminance temporarily generated when the transmittance is variable. Unevenness can be prevented.

(5) In (4), the light control device is
The rectangular wave signal is emitted to the light control film through a resistor,
The time constant circuit is
A light control system formed by at least the resistor and the capacitance of the light control film.

According to (5), the amplitude of the rectangular wave signal can be gradually increased with a simple configuration by effectively using the capacitance of the light control film.

(6) a light control film for controlling the transmitted light by aligning the liquid crystal of the liquid crystal cell sandwiched between linearly polarizing plates by the VA method;
A light control device having a drive power generation unit that outputs a rectangular wave signal to the light control film;
The light control device is:
By varying the amplitude of the rectangular wave signal in response to the operation of the operation element, the transmittance of the light control film is varied,
The light control film is
A first laminate in which a transparent electrode and an alignment layer are arranged on a substrate made of a transparent film material;
A second laminate in which a transparent electrode and an alignment layer are arranged on a substrate made of a transparent film material;
A liquid crystal layer sandwiched between the first and second laminates,
Supplying the rectangular wave signal to the transparent electrodes of the first and second laminates to control the transmitted light;
A dimming system further comprising a time constant circuit that gradually increases the amplitude of the rectangular wave signal applied to the transparent electrodes of the first and second laminates at least when the amplitude of the rectangular wave signal is increased.

According to (6), the amplitude of the rectangular wave signal applied to the transparent electrode is gradually increased by the time constant circuit of the light control film, and the liquid crystal is tilted in a state where the directions of the major axis of the liquid crystal are aligned. it can. As a result, it is possible to shorten the time until the tilted liquid crystal orientations are aligned and to prevent uneven brightness that temporarily occurs when the transmittance is variable.

(7) In (6),
The time constant circuit is
A dimming system formed by at least a resistor and a capacitance between the transparent electrodes of the first and second laminates.

According to (7), the amplitude of the rectangular wave signal can be gradually increased with a simple configuration by effectively using the capacitance of the light control film.

(8) A light control device having a drive power generation unit that outputs a rectangular wave signal to the light control film,
The light control film is
Control the transmitted light by aligning the liquid crystal of the liquid crystal cell sandwiched by the linear polarizing plate by the VA method,
The light control device is:
By varying the amplitude of the rectangular wave signal in response to the operation of the operation element, the transmittance of the light control film is varied,
A dimming device that gradually increases the amplitude of the rectangular wave signal when increasing the amplitude of the rectangular wave signal.

According to (8), by gradually increasing the amplitude of the rectangular wave signal, the liquid crystal can be tilted in a state where the directions of the major axis directions of the liquid crystal are aligned. As a result, it is possible to shorten the time until the tilted liquid crystal orientations are aligned, and to prevent uneven brightness that temporarily occurs when the transmittance is variable.

(9) In the light control film for controlling the transmitted light by aligning the liquid crystal of the liquid crystal cell sandwiched between the linear polarizing plates by the VA method,
A first laminate in which a transparent electrode and an alignment layer are arranged on a substrate made of a transparent film material;
A second laminate in which a transparent electrode and an alignment layer are arranged on a substrate made of a transparent film material;
A liquid crystal layer sandwiched between the first and second laminates,
Controlling transmitted light according to a rectangular wave signal applied to the transparent electrodes of the first and second laminates,
The light control film which increases gradually the amplitude of the said rectangular wave signal applied to the transparent electrode of the said 1st and 2nd laminated body by a time constant circuit when the amplitude of the said rectangular wave signal increases.

(9) According to (9), by gradually increasing the amplitude of the rectangular wave signal, the liquid crystal can be tilted in a state where the directions of the major axis directions of the liquid crystal are aligned. As a result, it is possible to shorten the time until the tilted liquid crystal orientations are aligned, and to prevent uneven brightness that temporarily occurs when the transmittance is variable.

(10) a light control film that controls the transmitted light by aligning the liquid crystal of the liquid crystal cell sandwiched between linearly polarizing plates by the VA method;
A light control device having a drive power generation unit that outputs a rectangular wave signal to the light control film;
The light control device is:
By varying the amplitude of the rectangular wave signal in response to the operation of the operation element, the transmittance of the light control film is varied,
A dimming system that applies a voltage having a certain value with a certain polarity in advance for a certain period of time before increasing the amplitude of the rectangular wave signal.

(11) The predetermined period is 5 milliseconds or more.

(12) The predetermined period is 100 milliseconds or less.

(13) In the driving method of the light control film, which controls the transmitted light by aligning the liquid crystal of the liquid crystal cell sandwiched by the linearly polarizing plates by the VA method.
In response to the operation of the operation element, by changing the amplitude of the rectangular wave signal by the rectangular wave signal output to the light control film, the transmittance of the light control film is changed,
A method for driving a light control film, wherein the amplitude of the rectangular wave signal is gradually increased when increasing the amplitude of the rectangular wave signal.

According to (13), by gradually increasing the amplitude of the rectangular wave signal, it is possible to tilt the liquid crystal in a state where the directions of the major axes of the liquid crystal are aligned. As a result, it is possible to shorten the time until the tilted liquid crystal orientations are aligned, and to prevent uneven brightness that temporarily occurs when the transmittance is variable.

(14) A driving voltage is applied between the liquid crystal layer in which the liquid crystal molecules are disposed and the light control film having two planar electrodes disposed so as to face each other and sandwich the liquid crystal layer. And a control unit that controls the transmittance of the light control film according to the value of the driving voltage, and the control unit applies a preliminary voltage smaller than the driving voltage between the electrodes prior to the application of the driving voltage. Dimming system.

(15) In (14), the preliminary voltage is a voltage for inclining the liquid crystal molecules 1 degree or more and 5 degrees or less from the normal line of the surface of the light control film.

(16) In (14) or (15), the light control film is disposed on a sunroof of a vehicle, and the liquid crystal molecules fall when the light control film is viewed from below with the vehicle traveling direction set to 0 °. The azimuth angle is not less than 45 degrees and not more than 90 degrees.

(17) In (14) or (15), the light control film is disposed on a sunroof of a vehicle, and the liquid crystal layer is a first region in which the liquid crystal molecules are tilted in two directions different from each other by 90 degrees by the driving voltage. And the second region, the traveling direction of the vehicle is 0 °, and the azimuth angle of the liquid crystal molecules disposed in the first region when viewed from below is 0 ° or more and 30 ° Below 90 degrees and 90 degrees.

(18) In (14) or (15), the light control film is held on a sunroof of a vehicle, and the liquid crystal layer is a first region in which the liquid crystal molecules are tilted in two directions different from each other by 180 degrees by the driving voltage. And the second region, the traveling direction of the vehicle is 0 °, and when the light control film is viewed from below, the azimuth angle of the liquid crystal molecules disposed in the first region is 45 degrees or less 130 Less than or equal to degrees.

(19) A light control film having a liquid crystal layer in which liquid crystal molecules are arranged, and two planar electrodes arranged so as to face each other and sandwich the liquid crystal layer, and attached to a sunroof, and the electrode A control unit that controls the transmittance of the light control film according to a value of a driving voltage applied between the electrodes, and the control unit applies a preliminary voltage smaller than the driving voltage prior to the application of the driving voltage to the electrode. Vehicle applied between.

(20) A driving voltage applied between the electrodes in a light control film having liquid crystal layers in which liquid crystal molecules are disposed and two planar electrodes disposed so as to face each other and sandwich the liquid crystal layer A light control film driving method for controlling the transmittance of the light control film according to the value of the light control film, wherein a preliminary voltage smaller than the drive voltage is applied between the electrodes prior to the application of the drive voltage. Driving method.

According to the present invention, it is possible to prevent uneven brightness that temporarily occurs when the transmittance is variable in a light control film using liquid crystal.
In addition, according to the present invention, it is possible to provide a light control system, a vehicle, and a light control film driving method capable of reducing deterioration in response speed and non-uniform transmittance when used in a vehicle or the like. it can.

It is sectional drawing which shows the light control film which concerns on 1st Embodiment of this invention. It is a figure where it uses for description of a measurement of brightness nonuniformity. It is a graph which shows the measurement result of the response speed at the time of sticking a light control film on curved glass. It is a graph which shows the measurement result of the response speed at the time of sticking a light control film on plane glass. It is a characteristic curve figure which shows the measurement result of the change of an electrostatic capacitance, and the change of the transmittance | permeability of a light control film. It is a figure which shows the behavior of the horizontal alignment of a liquid crystal. It is a characteristic curve figure which shows the amplitude of a rectangular wave signal. It is a figure which shows the light control system which concerns on 1st Embodiment of this invention. It is a figure where it uses for description of the drive power supply in the light modulation system of FIG. It is a figure which shows the change of the transmittance | permeability by the drive power supply of FIG. It is a figure which shows the light control system which concerns on 2nd Embodiment of this invention. It is a figure where it uses for description of the drive power supply in the light modulation system of FIG. It is a figure which shows the change of the transmittance | permeability by the drive power supply of FIG. It is a figure where it uses for description of starting of the drive power supply which concerns on 4th Embodiment of this invention. It is a figure where it uses for description of a modulation degree and a tilt angle. It is a figure which shows the relationship between the amplitude value of a rectangular wave signal, and the transmittance | permeability. It is a figure where it uses for description of the light control system which concerns on 5th Embodiment of this invention, (A) is 5th Embodiment, (B) is a comparison form. It is a figure which shows the vehicle provided with the light control system which concerns on embodiment of this invention. It is a block diagram of the light control system which shows the light control film and the control part which drives the light control film. In a comparative form, it is a characteristic curve figure explaining the behavior of a liquid crystal molecule when the drive voltage of +/- 10V is applied between the transparent electrodes whose voltage is 0V. It is a figure explaining the behavior of a liquid crystal molecule. In 6th Embodiment, it is a characteristic curve figure which shows the voltage applied between transparent electrodes, and the transmittance | permeability of the light control film in that case. It is a figure explaining the definition of the polar angle and azimuth in a single domain system, (A) is a schematic sectional drawing of a light control film, (B) is a figure explaining the polar angle of a liquid crystal molecule, (c) is a liquid crystal It is a figure explaining the direction in which a molecule falls. It is a figure which shows the change of the transmittance | permeability when the directions in which a liquid crystal molecule falls differ. It is a figure explaining the preferable range of the direction in which the liquid crystal molecule falls in 6th Embodiment. It is a figure explaining the direction in which a liquid crystal molecule falls in 7th Embodiment. In the light control film of 7th Embodiment, it is a figure which shows the change of the transmittance | permeability when the direction in which a liquid crystal molecule falls differs. It is a figure explaining the preferable range of the direction in which the liquid crystal molecule falls in 7th Embodiment. It is a figure explaining the direction in which a liquid crystal molecule falls in 8th Embodiment. In the light control film of 8th Embodiment, it is a figure which shows the change of the transmittance | permeability when the direction in which a liquid crystal molecule falls differs. It is a figure explaining the preferable range of the direction in which the liquid crystal molecule falls in 8th Embodiment.

[First Embodiment]
[Light control film]
FIG. 1 is a cross-sectional view showing a light control film 10 applied to the light control system of the present invention.
The light control film 10 in this embodiment is affixed to a sunroof or the like of a vehicle, for example, and is at least 1 cm ² per domain, that is, a size of 1 cm ² or more per domain, preferably 10 cm. ^two or more of which is size. One domain refers to a continuous region in which liquid crystals are aligned in the same direction after a certain period of time.
This light control film 10 is a film material that controls transmitted light using liquid crystal, and controls the transmitted light by changing the orientation of the liquid crystal by the VA method by changing the applied voltage.

The light control film 10 is configured by sandwiching a liquid crystal cell 14 for light control film between linear polarizing plates 12 and 13. Here, the linear polarizing plates 12 and 13 are formed by impregnating polyvinyl alcohol (PVA) with iodine or the like and then stretched to form an optical functional layer that performs an optical function as a linear polarizing plate. TAC (triacetyl cellulose) The optical functional layer is sandwiched between base materials made of a transparent film material such as the above.
The linearly polarizing plates 12 and 13 are arranged in the liquid crystal cell 14 by an adhesive layer made of an ultraviolet curable resin or the like in a crossed Nicol arrangement. The linear polarizing plates 12 and 13 are provided with retardation films 12A and 13A for optical compensation on the liquid crystal cell 14 side, respectively, but the retardation films 12A and 13A may be omitted as necessary.

The liquid crystal cell 14 controls the polarization plane of transmitted light by an applied voltage to a transparent electrode described later. Thereby, the light control film 10 is comprised so that transmitted light can be controlled and various light control can be aimed at.

[Liquid crystal cell]
The liquid crystal cell 14 is configured by sandwiching a liquid crystal layer 18 between a lower laminate 15D and an upper laminate 15U which are first and second laminates in a film shape.
The lower laminate 15D is formed by forming the transparent electrode 21, the spacer 22, and the alignment layer 23 on the base material 16 made of a transparent film material. The upper laminate 15U is formed by laminating a transparent electrode 26 and an alignment layer 27 on a substrate 25 made of a transparent film material. The liquid crystal cell 14 controls the orientation of the liquid crystal provided in the liquid crystal layer 18 by the VA method by driving the transparent electrodes 21 and 26 provided in the lower stacked body 15D and the upper stacked body 15U. Control the plane of polarization. In this embodiment, the liquid crystal cell 14 is configured by a single domain method, but may be configured by a multi-domain method.

Although various transparent film materials applicable to this kind of film material can be applied to the base materials 16 and 25, it is desirable to apply a film material with small optical anisotropy. In this embodiment, although a polycarbonate film is applied to the substrates 16 and 25, a COP (cycloolefin polymer) film or the like may be applied.

Various electrode materials applied to this kind of film material can be applied to the transparent electrodes 21 and 26. In this embodiment, the transparent electrodes 21 and 26 are formed of a transparent electrode material made of ITO (Indium Tin Oxide).
The spacer 22 is provided to define the thickness of the liquid crystal layer 18 and various resin materials can be widely applied. However, in this embodiment, the spacer 22 is made of a photoresist, and is made of a transparent electrode 21. It is produced by applying a photoresist on 16 and exposing and developing. The spacer 22 may be provided on the upper laminate 15U, or may be provided on both the upper laminate 15U and the lower laminate 15D. The spacer 22 may be provided on the alignment layer 23. Further, a so-called bead spacer may be applied as the spacer.

The alignment layers 23 and 27 are formed of a photo-alignment layer. Here, as the photo-alignment material applicable to the photo-alignment layer, various materials to which the photo-alignment technique can be applied can be widely applied. However, in this embodiment, for example, a photo-dimerization type material is used. For this light dimerization type material, please refer to “M. Schadt, K. Schmitt, V. Kozinkov and V. Chigrinov: Jpn. J. Appl. Phys., 31, 2155 (1992)”, “M. Schadt, H. Seiberle and A. Schuster: Nature, 381, 212 (1996) ".

Various liquid crystal materials applicable to this type of light control film can be widely applied to the liquid crystal layer 18. Specifically, a liquid crystal material such as MLC 2166 manufactured by Merck Co., for example, can be applied to the liquid crystal layer 18. In the liquid crystal cell 14, a sealing material 29 is disposed so as to surround the liquid crystal layer 18, and the upper stacked body 15 </ b> U and the lower stacked body 15 </ b> D are integrally held by the sealing material 29, thereby preventing leakage of the liquid crystal material. . Here, as the sealing material 29, for example, an epoxy resin, an ultraviolet curable resin, or the like can be applied.
In the present embodiment, no structure other than the spacer 22 is arranged in the liquid crystal layer 18. That is, regular structures such as a gate electrode and a source electrode, such as a TFT, which are disposed in a pixel of a display, for example, are disposed in a region constituting the liquid crystal layer 18 of one domain. Not. Accordingly, no structure that is an obstacle to the movement of the liquid crystal when the liquid crystal molecules are tilted is disposed in the region constituting the one-domain liquid crystal layer 18.

Thus, the light control film 10 controls the alignment of the liquid crystal provided in the liquid crystal layer 18 by the applied voltage V1 between the transparent electrodes 21 and 26 of the upper laminate 15U and the lower laminate 15D. Here, the applied voltage V <b> 1 is applied between the transparent electrodes 21 and 26 by the drive power source S <b> 1 using a rectangular wave signal whose polarity is switched at regular time intervals. In this embodiment, by applying the VA method, the liquid crystal molecules of the liquid crystal layer 18 are vertically aligned when no electric field is applied when the amplitude of the drive power supply S1 is 0 V (when the applied voltage V1 is 0 V), Thereby, the light control film 10 light-shields incident light, and will be in the light-shielding state. Further, when the amplitude of the driving power source S1 is increased and the applied voltage V1 is raised, the liquid crystal of the liquid crystal layer 18 is horizontally aligned, and the light control film 10 transmits incident light.

[Brightness unevenness]
FIG. 2 is a diagram for explaining the light control film 10 used for checking luminance unevenness that occurs when the transmittance is variable. In this confirmation, the light control film 10 having the configuration described above with reference to FIG. 1 was manufactured with a size of 300 mm × 300 mm. Furthermore, this light control film 10 was divided equally in the horizontal direction, and five areas indicated by reference signs A1, A2, A3, A4, and A5 were set. In addition, each region set in the horizontal direction in this way was divided into equal parts in the vertical direction, and three regions indicated by reference numerals B1, B2, and B3 were set. Further, the change in transmittance with respect to the change in the applied voltage V1 was measured at the center of each region set in this way. The driving power source S1 related to the applied voltage V1 was supplied from the center in the horizontal direction and the lower end in the vertical direction. In the light control film 10, the liquid crystal molecules were set so as to be horizontally aligned in the direction from the upper left to the lower right.

3 and 4 are charts showing the measurement results. 3 and 4 show the results of measuring the time required for the transmittance to change to a value corresponding to the rise of the amplitude after the amplitude of the applied voltage V1 is raised. The time required for the change in transmittance described in FIGS. 3 and 4 is the time required until 90% of the transmittance corresponding to the raised amplitude is obtained. In the following, the time required to reach 90% will be appropriately referred to as response speed.

FIG. 3 is a measurement result of the response speed when the light control film is attached to the curved glass, and FIG. 4 is a measurement result of the response speed when the light control film is attached to the flat glass. . In the measurement results of FIG. 3 and FIG. 4, although differences are seen in the regions A3 and B1 and the regions A4 and B1, the time required for the change in transmittance is from 22 milliseconds to 150 in both FIG. 3 and FIG. It turns out that it varies in the range up to milliseconds.
In the light control film, due to this variation, in the region where the time required for the change is short, the region where the time required for the change is still maintained in the light-shielded state even though the light-shielding state has already been switched from the light-shielding state to the light-transmitting state. As a result, it was found that uneven brightness occurred temporarily when the transmittance was variable. It has been confirmed that this luminance unevenness does not depend on the power supply location because it occurs even when the power supply location is changed. Further, even if the thickness of the transparent electrodes 21 and 26 is changed, it is not caused by the influence of the resistance of the transparent electrodes 21 and 26.

Thus, further investigation was made on the startup of this drive power supply S1. FIG. 5 shows the measurement results of the change ΔC in capacitance of the liquid crystal cell constituting the light control film and the change ΔT in transmittance of the light control film. This measurement result of the transmittance is a measurement result of the central regions A3 and B2 when the light control film is attached to the flat glass. In FIG. 5, the vertical axis represents the capacitance and transmittance expressed by normalizing the measured value at each time point by setting the capacitance and transmittance corresponding to the raised amplitude to a value of 1.

According to FIG. 5, it can be seen that the capacitance of the liquid crystal cell is saturated in a very short time as shown by the period T1. On the other hand, as shown by the period T2, it can be seen that the transmittance takes 300 msec or more until the saturation finally occurs after the period T1 elapses.

Here, as shown by the arrows in FIG. 6, in the light control film 10, the liquid crystal molecules 18A of the liquid crystal layer 18 fall from the vertical alignment state to the horizontal alignment state in a short time by raising the amplitude of the applied voltage V1.

The period required for this collapse is a period T1 during which the capacitance changes. However, the liquid crystal molecules 18A tilted in the horizontal direction vary in the direction of the major axis, and this variation is corrected by the alignment regulating force related to the pretilt of the alignment layers 23 and 27 as indicated by the arrows for the period T2. Thus, the major axis direction of the liquid crystal molecules 18A is aligned with the direction related to the pretilt. The period required for correction after falling down in the horizontal direction is the period T2, and as a result, the period T2 requires a time of about 200 msec at the maximum. Further, when this period T2 is different in each part, luminance unevenness occurs. FIG. 6 is a diagram showing the behavior of the liquid crystal molecules 18A in the periods T1 and T2, the Z direction is the thickness direction of the liquid crystal layer 18, and the X direction and the Y direction are described above with reference to FIGS. Horizontal and vertical directions.

Here, there are various causes for the variation in the period T2. However, if the liquid crystal is tilted so that the orientation of the major axis direction of the liquid crystal does not vary (horizontal alignment), the period T2 can be shortened, and further, the period T2 can be prevented from varying. Thus, it is considered that luminance unevenness when the transmittance is reduced can be prevented. Further, if the period T2 is shortened in this way, luminance unevenness can be made difficult to visually recognize. For this purpose, it is considered that if the amplitude of the applied voltage is gradually increased, the orientation of the liquid crystal in the major axis direction does not vary when the liquid crystal falls down.

Here, FIG. 7A shows a change in the amplitude of the applied voltage V1 during the measurement described above with reference to FIGS. In the examples of FIGS. 2 and 3, the transmittance is increased by raising the amplitude of the applied voltage V1 from 0 V to 10 V, the above-described luminance unevenness occurs, and the period T2 varies.
Here, the light control film 10 is not disposed other than the spacer 22 in the liquid crystal layer 18 as described above. For this reason, such luminance unevenness occurs when the amplitude of the applied voltage V1 rises from 0V. That is, such luminance unevenness occurs when the transmittance is increased from the minimum state in the case of normally black, but the applied voltage from the intermediate value (halftone) state where the transmittance is not minimum. It does not occur when the amplitude of V1 is increased and the transmittance is further increased.
Note that 0 V in this case is not limited to a complete 0 V, but the voltage range of the threshold voltage of the liquid crystal (until the transmittance begins to change) is increased by increasing the amplitude of the applied voltage V 1 from 0 V. Including, generally 2V or less.

Therefore, in this embodiment, as shown in FIG. 7B, the amplitude of the drive voltage V1 is gradually increased by increasing the amplitude of the drive voltage V1 step by step, for example, in three steps at short time intervals. Here, according to the results of experiments conducted by changing the time interval related to the step-up of the amplitude, the response speed could be 50 msec or less, and the luminance unevenness could not be visually recognized.

In the case where the amplitude is gradually increased as described above, when the amplitude is increased in three steps as shown in FIG. 7B, the liquid crystal molecules 18A fall down in three steps in the period T1 described in FIG. The liquid crystal molecules 18A are tilted while being aligned in the same direction, and in this case, it is not necessary to change the orientation of the liquid crystal molecules 18A in the in-plane direction. it is conceivable that.

Here, as shown in FIG. 7C, the increase in the amplitude may be continuously increased by the characteristic of the linear function, the characteristic of the logarithmic function, or the like instead of the stepwise increase.

Here, when the amplitude is increased in multiple steps as shown in FIG. 7B, or when the amplitude is continuously increased as shown in FIG. 7C, the response speed may be 50 milliseconds or less. Although the response speed can be selected, a longer period can be selected depending on the application.
For example, when the response speed is 100 to 300 milliseconds, an impression that the transmittance of the light control film changes instantaneously can be obtained.
When the response speed is set to about 500 milliseconds to 3 seconds and the amplitude is gradually increased, the transmittance of the light control film gives an impression that it becomes brighter slowly.
When the response speed is increased from 300 milliseconds to 500 milliseconds and the amplitude is gradually increased at a frequency of 30 to 50 Hz, an impression that the transmittance of the light control film is naturally brightened is obtained. The response speed can be appropriately set according to the use of the light control film.
Note that when the response speed is longer than 3 seconds, the change in transmittance seems to be considerably slow, so the response speed is preferably set to 3 seconds or less. Further, if the drive voltage V1 has the same amplitude of 100 milliseconds or more in the middle of changing the transmittance, the change in the transmittance may seem unnatural. Less than milliseconds are preferred.

[Light control system]
FIG. 8 is a diagram showing a light control system according to this embodiment. The dimming system 1 is applied to, for example, a passenger car, and holds and holds the dimming film 10 on a curved surface glass of a sunroof, and the dimming system 1 is adjusted by operating up and down operators 2U and 2D provided in a console box or the like. The transmittance of the light control film 10 is controlled by the optical device 3. For this reason, the light control device 3 outputs the drive power source S1 to the light control film 10, and varies the amplitude of the drive power source S1 in response to the operation of the operation elements 2U and 2D.

That is, in the dimming device 3, the drive power generation unit 5 is a power supply circuit that generates and outputs the drive power S1. The drive power generation unit 5 generates the drive power S1 from a rectangular wave signal having a duty ratio of 50% and a frequency of 30 Hz, and outputs the drive power S1 to the light control film 10. In addition, this frequency can be set to a low frequency in a range that does not cause deterioration of the liquid crystal in the light control film 10, and power loss due to the capacitance of the light control film 10 can be reduced. It is desirable to output at a frequency of 1 Hz to 120 Hz, more preferably 1 Hz to 30 Hz. The drive power generator 5 varies the amplitude of the drive power S 1 under the control of the controller 4.

The controller 4 is a control circuit that controls the operation of the light control device 3, and records and holds information related to light control of the light control film 10 in a storage means (not shown). Here, the information related to the dimming control is information specifying the relationship between the amplitude of the drive power source S1 and the transmittance, for example. When the supply of power from the vehicle is started, the controller 4 outputs the drive power S1 according to the default setting. Thereby, in this light control system 1, for example, the drive power supply S1 is output according to the setting at the time of power-off, or the drive power supply S1 is output so as to be in a light shielding state.

When the drive power source S1 is output in this way and the up operation element 2U or the down operation element 2D is pressed, the amplitude of the drive power supply S1 is increased or decreased to correspond to this operation, and the operation is thereby performed. The transmittance is varied in response to the operation of the children 2U and 2D. In this process, the controller 4 changes the amplitude of the drive power source S1 so that the transmittance is sequentially changed by a constant value by the operation of the operation elements 2D and 2U based on the information relating to the light control stored and held in the storage means. To do.

On the other hand, when the operation elements 2D and 2U are pressed for a long time, the amplitude of the drive power source S1 is varied so that the transmittance changes greatly. In increasing the amplitude of the drive power source S1, when increasing the amplitude, the controller 4 gradually increases the amplitude of the rectangular wave signal, thereby preventing luminance unevenness.

Specifically, as shown in FIG. 9, the controller 4 gradually increases the amplitude of the rectangular wave signal in a plurality of cycles of the driving power source S1 that is a rectangular wave signal. That is, in the example of FIG. 9, the amplitude is increased in a linear function in three cycles of the drive power source S1. In this way, the change ΔT in the passage rate is changed to 90% transmittance in a period of approximately two cycles, which is three cycles or less, thereby preventing luminance unevenness.

FIG. 10 is a characteristic curve diagram showing the change in transmittance due to the amplitude change in FIG. 9 by comparison with the measurement result in FIG. The measurement result in FIG. 5 is indicated by reference numeral T1, and the change in transmittance in the example of FIG. 9 is indicated by reference numeral T2. According to FIG. 10, it is possible to confirm a marked improvement in response speed.

When the liquid crystal is driven by the AV method, the orientation of the liquid crystal molecules 18A is in a range where the amplitude of the rectangular wave signal is 25% or more and 50% or less with respect to the amplitude of the rectangular wave signal having a modulation degree of 100%. It can be said that the change in transmittance due to the change is a large range. In this range, the period T2 becomes longer due to a sudden increase in amplitude, and the variation in the period T2 also increases. The modulation degree is a ratio of the transmittance indicating that the transmittance is most increased as 100% modulation. When the transmittance is variable, the variation of the transmittance in each part increases.

In the example of FIG. 9, when the amplitude of the drive voltage V1 is increased so as to cross the range of 25% or more and 50% or less, the amplitude is increased in three cycles to ensure the response speed in the period of two cycles. , Brightness unevenness can be prevented. As a result, the amplitude of the rectangular wave signal is gradually increased, such as by gradually increasing the amplitude of the rectangular wave signal only when the amplitude is varied within the range of 25% to 50%, for example, 10% or more. The application conditions in the case of making them can be set variously as needed.

According to this embodiment, when the amplitude of the rectangular wave signal is increased, by gradually increasing the amplitude of the rectangular wave signal, the liquid crystal molecules fall down while being aligned in the same direction, and thereby the orientation of the liquid crystal molecules is bothered. Since there is no need to change so as to align in the in-plane direction, the response speed can be improved and luminance unevenness can be prevented.

Further, at this time, the luminance unevenness can be prevented by a specific configuration by sequentially increasing the amplitude in a plurality of cycles of the driving power source by the rectangular wave signal.

[Second Embodiment]
FIG. 11 is a diagram showing a light control system according to the second embodiment of the present invention. The light control system 31 is configured in the same manner as the light control system 1 except that a light control device 33 is applied instead of the light control device 3. Here, in the dimming device 33, the drive power generation unit 35 outputs the drive power S1 with the amplitude varied under the control of the controller 34. The controller 34 responds to the operation of the operation elements 2U and 2D and controls each part. Control the behavior. In this embodiment, the light control device 33 includes a resistor R1 on the cold output line of the drive power source S1, and a rectangular wave is generated by a time constant circuit formed by the resistor R1 and the capacitance of the light control film 10. Brightness unevenness is prevented by gradually increasing the amplitude of the signal. This embodiment has the same configuration as that of the first embodiment except that the configuration related to the rise of the amplitude is different.

That is, the light control film 10 is held so that the transparent electrodes 21 and 26 are opposed to each other with an interval depending on the thickness of the liquid crystal layer 18, thereby providing a capacitance. Thus, if the resistor R1 is provided on the ground side (cold side) output line of the drive power source S1 and the drive power source S1 is supplied via the resistor R1, the time constant circuit is formed by the capacitance and the resistor R1. Thus, the waveform of the driving power supply applied to the transparent electrodes 21 and 26 is blunted. As a result, as shown in FIG. 12B by comparison with a state where the waveform is not blunted (FIG. 12A), the polarity of the voltage V1 in each cycle of the driving power source S1 by the rectangular wave signal is changed. The amplitude of the rectangular wave signal will gradually increase. Here, the waveform dullness of the drive power supply can be adjusted by the resistor R1.

Based on this principle, the light control device 33 gradually increases the amplitude of the drive power source S1 to prevent uneven brightness. However, when the waveform of the drive power source S1 is dulled as described above, power is consumed by the resistor R1, and the power consumption increases. Therefore, the dimmer 33 is provided with a switch circuit 37 in parallel with the resistor R1, and both ends of the resistor R1 are short-circuited by the switch circuit 37 to prevent useless power consumption. Specifically, the switch circuit 37 is set to an ON state except when it is necessary to prevent luminance unevenness, thereby preventing wasteful power consumption. When it is necessary to prevent this luminance unevenness, for example, as described above with respect to the first embodiment, the amplitude of the drive power source S1 is in the range of 25% to 50% with respect to the drive voltage with a modulation degree of 100%. In the case where the magnitude of the variable amplitude is 12.5% or more.

Further, even when the switch circuit 37 is set to an off state in order to prevent uneven brightness, the switch circuit 37 is switched to an off state when the amplitude is increased and a certain time (for example, 200 msec) elapses. Prevents wasteful power consumption. Here, the resistor R1 and the switch circuit 37 may be provided on both of the drive power supply output lines or on the hot side. In addition, resistance R1 can be suitably set according to the electrostatic capacitance of the light control film which changes with the magnitude | size of a light control film according to the time constant desired. Note that the switch circuit 37 may be omitted as necessary.

FIG. 13 is a characteristic curve diagram showing measurement results of transmittance and amplitude according to this embodiment. In the measurement result of FIG. 13, the time constant was set from 0.5 milliseconds to 2 milliseconds, and the response speed could be set to about 0.03 seconds. As a result, when the amplitude is gradually increased in each cycle of the drive power source by the time constant circuit in this way, the variation in response speed in each part is simply reduced by the liquid crystal molecules falling together, and the luminance unevenness is reduced. Can be prevented.

According to this embodiment, the same effect as that of the first embodiment can be obtained by gradually increasing the amplitude in each cycle of the drive power supply by the time constant circuit.

In addition, by forming this time constant circuit with the resistor provided in the output line of the drive power supply of the light control device and the electrostatic capacity of the light control film, the electrostatic capacity of the light control film can be effectively achieved with a simple configuration. It is possible to prevent luminance unevenness by using it.

[Third Embodiment]
In this embodiment, the resistor R1 described above for the second embodiment is provided on the light control film side. In this case, the switch circuit 37 may also be provided on the light control film, and the on / off control may be performed by the light control device. This embodiment has the same configuration as that of the second embodiment except that the configuration regarding the resistor R1 is different.

In this embodiment, by providing a resistance to the light control film to form a time constant circuit, the light control device is commonly used in various light control films, and the same effect as in the second embodiment is obtained. be able to.

[Fourth Embodiment]
FIG. 14 is a diagram for explaining a light control system according to the fourth embodiment of the present invention. The dimming system according to this embodiment has the same configuration as that of the above-described embodiment except that the method of increasing the amplitude at the time of starting the amplitude shown in FIG. 14 is different.

In this embodiment, as indicated by reference numeral V1B, when the amplitude is increased in a certain range, the driving power source is increased by a certain value VA with a certain polarity in advance for a certain period TA. Thereafter, in this embodiment, the drive power supply is raised to an amplitude corresponding to the user's instruction and driven by a rectangular wave signal. As a result, in this embodiment, the amplitude of the rectangular wave signal is gradually increased by two steps based on the predetermined constant value VA and the amplitude corresponding to the user's instruction, and luminance unevenness that temporarily occurs when the transmittance is variable is reduced. To prevent. In FIG. 14, the applied voltage when driven by a driving power source using a rectangular wave signal is denoted by reference symbol V1A, and the change in transmittance in this case is denoted by reference symbol ΔT1.

Here, the fixed period TA is not related to the period of the rectangular wave signal, and is preferably 5 milliseconds or more, and more preferably 10 milliseconds or more. Moreover, it is preferably 100 milliseconds or less, more preferably 50 milliseconds or less.
If a time shorter than 5 milliseconds is set, the liquid crystal molecules do not move and the effect of improving the response speed cannot be obtained. On the other hand, if the time is longer than 100 milliseconds, it is not preferable because the liquid crystal molecules can be visually recognized that the liquid crystal molecules operate to a modulation degree lower than a desired modulation degree and further operate to a desired transmittance in two stages. Therefore, for the fixed period TA, as described above, the lower limit value is set to 5 milliseconds or more, more preferably 10 milliseconds or more, and the upper limit value is set to 100 milliseconds or less, more preferably 50 milliseconds or less. Desirably, in such a short time, the change in transmittance of the light control film seems to operate continuously.

According to the present embodiment, the fixed period TA does not depend on the amplitude of the rectangular wave signal, and can be set to a desired preferable range.

Further, the predetermined range for increasing the amplitude in advance is the same as the case where the amplitude of the rectangular wave signal according to the above-described embodiment is gradually increased, and there is a possibility that uneven brightness may occur.

The constant value VA is a voltage corresponding to a modulation degree of 0% or more and 80% or less. For example, a voltage that modulates about 20% according to a final amplitude value corresponding to a user's instruction. It can be set arbitrarily within the range.

Here, as shown in FIG. 15, the modulation degree of the liquid crystal molecules changes due to the change of the tilt angle. When the tilt angle is 90 and the liquid crystal molecules are horizontally aligned, the modulation degree is 1 and the tilt angle is 0 degree. In the case of vertical alignment, the modulation degree is zero. Here, when the degree of modulation is 0% or more and 80% or less (the range indicated by the symbol M), the light control film has a high effect of reducing luminance unevenness by gradually increasing the amplitude. This is a case where the degree of modulation exceeds 80%. When the liquid crystal molecules are largely inclined, the liquid crystal molecules are already oriented in various directions, so that even if the amplitude is gradually increased, the driving unevenness can be improved. On the other hand, when the degree of modulation is 80% or less, the liquid crystal molecules are not tilted greatly, and the amplitude of the rectangular wave signal can be gradually raised to sufficiently align the liquid crystal molecules and bring down the brightness unevenness. Can be reduced. Here, this range is a range M of 5 degrees or more and 55 degrees or less according to the tilt angle.

Here, in this tilt angle range, as shown in FIG. 16, the amplitude of the rectangular wave signal is in the range of 2.5V to 5V.

Thus, in this embodiment, the constant value VA is set to 2.5 V or more and 5 V or less by increasing the driving power source by a certain value VA with a certain polarity in advance.

According to this embodiment, the drive power supply is increased by a fixed value VA with a fixed polarity in advance for a fixed period TA, and then the amplitude of the rectangular wave signal is gradually increased by driving with the rectangular wave signal. Even if it does, the effect similar to the above-mentioned embodiment can be acquired.

[Fifth Embodiment]
FIG. 17 is a diagram for explaining a light control system according to a fifth embodiment of the present invention, in which (A) is a fifth embodiment, and (B) is a comparative embodiment. The dimming system according to this embodiment is configured in the same way as the fourth embodiment except that the method of increasing the amplitude at the time of starting up the amplitude is different, and thus the description of the same part is omitted.
The dimming system has a clock inside, and the drive signal is transmitted based on the clock signal. That is, the timing at which the amplitude of the drive signal changes depends on the clock signal.
That is, the amplitude of the drive signal is changed by the clock signal regardless of the timing when the user turns on the light control system in order to change the transmittance of the light control film.

In this embodiment, before applying the amplitude VC corresponding to the user's instruction to the light control film, a voltage having an amplitude VA2 smaller than the amplitude VC is applied to the light control film. Also in this embodiment, the time TA for applying the voltage of the amplitude VA2 to the light control film is set in a range where the lower limit value is 5 milliseconds or more and the upper limit value is 100 milliseconds or less, as in the fourth embodiment. Is preferred.

Here, since the frequency of the drive signal needs to be 30 Hz or higher in consideration of suppression of flicker (flicker), a case where one period is 33 milliseconds will be described.

First, as a comparative form shown in FIG. 17B, the time including the time when the SW / ON is performed from the time when the user turns on the switch of the dimming system (the SW / ON position in FIG. 17B). The case where the amplitude of the drive signal in the cycle is VA2 and the amplitude of the drive voltage is VC from the second cycle will be described.
In this comparative form, the remaining time t in the first cycle including the SW / ON time is TA. The remaining time t (TA) in the first cycle is 0 ≦ t (TA) ≦ 33 milliseconds, and may be t (TA) <5 milliseconds depending on the SW / ON timing. In this case, t (TA) deviates from the above-described preferable range, and the effect of improving the response speed cannot be obtained.

Therefore, in this embodiment, as shown in FIG. 17A, the SW / ON is performed from the time when the user turns on the switch of the dimming system (the SW / ON position in FIG. 17A). The amplitude of the drive voltage in the first cycle and the second cycle including the time point is VA2, and the amplitude of the drive voltage is VC from the next third cycle.
In the present embodiment, TA is a time obtained by adding 33 milliseconds of the first cycle to the remaining time t of the first cycle including the SW / ON time point. Since t is 0 ≦ t ≦ 33 milliseconds, 33 ≦ TA (t + 33) ≦ 66 milliseconds, and TA is a preferable range of 5 milliseconds to 100 milliseconds regardless of the SW / ON timing. Become.

In addition, when considering interference with external light such as a fluorescent lamp, there is a high possibility that the frequency of the driving voltage is 50 Hz. In this case, according to the present embodiment, the remaining time t in the first cycle including the SW / ON time is 0 ≦ t ≦ 20 milliseconds, and therefore 20 ≦ TA (t + 20) ≦ 40 milliseconds. However, regardless of the SW / ON timing, TA is in the preferred range of 5 milliseconds to 100 milliseconds.

Note that the TA is in the preferred range of 5 milliseconds to 100 milliseconds in this case when the length of one cycle is 5 milliseconds to 50 milliseconds.

[Sixth Embodiment]
〔vehicle〕
FIG. 18 is a diagram illustrating a vehicle including the light control system according to the embodiment of the present invention. The vehicle 130 includes a sunroof 132, and the light control film 10 is attached to the sunroof 132. The vehicle 130 is provided with an opening 131 so as to cover the passenger's head, and a laminated body of the light control film 10 is disposed in the opening 131 to form a sunroof 132.
In addition, the attachment object of the light control film 10 is not limited to a sunroof like this embodiment, A show window, the other window in a vehicle, the window of a building, etc. are applicable.

The vehicle 130 according to the present embodiment is used as a laminated body in which the driver's seat is disposed at the right front portion of the vehicle, and the sunroof 132 is laminated on the transparent plate member forming the sunroof 132 with an adhesive, an adhesive, or the like. . In addition to being held by pasting, the light control film may be disposed by applying to an intermediate material of laminated glass, for example.

Since the basic structure of the light control film 10 is the same as that of the light control film 10 of 6th Embodiment, the same code | symbol is attached | subjected and description of the overlapping part is abbreviate | omitted. In this embodiment, the linearly polarizing plates 12 and 13 are arranged in the liquid crystal cell 14 by an adhesive layer such as an acrylic transparent adhesive resin. In the present embodiment, a polycarbonate film having a thickness of 100 μm is applied to the base materials 16 and 25.
The alignment layers 23 and 27 may be produced by rubbing treatment instead of the photo-alignment layer, or may be produced by forming a fine line-shaped uneven shape.

The alignment layers 23 and 27 are formed by applying an alignment layer coating liquid, drying the film, and then exposing it to ultraviolet irradiation. In one of the alignment layers 23 and 27, a plurality of regions having different directions of alignment regulating force are created by repeated exposure processing using a mask in the irradiation of ultraviolet rays. In addition, the alignment layer 23 or 27 that remains is set to have a uniform alignment regulating force over the entire surface. Thereby, the light control film 10 drives the liquid crystal layer 18 by the multi-domain by two domains. Note that the present invention is not limited to the case of two domains, and may be applied to a multi-domain such as a 4-domain or a single domain.

A nematic liquid crystal can be applied to the liquid crystal layer 18.
For the alignment control of the liquid crystal layer 18 in the light control film 10 of the embodiment, a VA method (Vertical Alignment, vertical alignment type) or the like is applied.
In the VA system, the liquid crystal molecules of the liquid crystal layer 18 are vertically aligned when there is no electric field when the amplitude of the drive power supply 20 is 0 V (when the drive voltage is 0 V), whereby the light control film 10 blocks incident light. As a result, the light is blocked. When the drive voltage is increased by increasing the amplitude of the drive power supply 20, the liquid crystal layer of the liquid crystal layer 18 is horizontally aligned, and the light control film 10 transmits incident light.
In the present embodiment, the liquid crystal cell 14 is driven by a so-called single domain by patterning the photo-alignment layer or the like.

FIG. 19 is a block diagram of the light control system 200 showing the light control film 10 and the control unit 140 that drives the light control film 10.
The control unit 140 includes a drive power supply 20 and changes the amplitude in response to the operation of the operation element 141 to output the drive voltage V1.

The control unit 140 applies a rectangular wave driving voltage whose polarity is switched at regular time intervals between the lower transparent electrode 11 and the upper transparent electrode 16 of the light control film 10.
When a driving voltage is applied between the lower transparent electrode 11 and the upper transparent electrode 16 from the control unit 140, an electric field is generated in the liquid crystal layer 18. The alignment of the liquid crystal layer material provided in the liquid crystal layer 18 is controlled by the electric field generated in the liquid crystal layer 18. Thereby, the transmitted light of the light control film 10 can be controlled, and light control can be achieved.

[Comparison form]
[Behavior when standing still]
FIG. 20 is a comparative example, and is a characteristic curve diagram illustrating the behavior of liquid crystal molecules when a driving voltage V1 of ± 10 V is applied between the transparent electrodes 11 and 16 having a voltage of 0 V in the VA method. In addition, the measurement result of FIG. 20 is a measurement result in the state (not a moving vehicle) where the light control film 10 is left still.

When a drive voltage V1 of ± 10 V is applied between the transparent electrodes 11 and 16 having a voltage of 0 V, the transmittance is about 1/3 of the saturation value after about 10 msec has elapsed (in FIG. It is about 02). Thereafter, the transmittance once decreases to about 0.01, then gradually increases, and saturates at about 0.055 after about 200 msec.

The reason for such behavior is considered as follows.
FIG. 21 is a diagram for explaining the behavior of the liquid crystal molecules 18A in the comparative form. Hereinafter, for the sake of easy understanding, the same reference numerals as those of the present embodiment are used in the comparative embodiment. As shown in the figure, the liquid crystal molecules 18A of the nemac liquid crystal used in the VA mode fluctuate relatively freely in the major axis direction even in the state where the light control film 10 is allowed to stand at the time of vertical alignment which is light shielding. The liquid crystal molecules 18A have a certain distribution in which the direction in the major axis direction has a certain degree of spread around the direction related to the pretilt angle θ.
In FIG. 21, the xy direction is the in-plane direction of the surface of the liquid crystal layer 8, and the z direction is the thickness direction of the liquid crystal layer 18. The pretilt angle θ of the liquid crystal molecules 18A is about 0.5 degrees from the normal line of the surface of the light control film 10.

From such a state, when a voltage is applied between the transparent electrodes 21 and 26 to cause horizontal alignment, each liquid crystal molecule 18A first has a direction (vertical alignment) corresponding to the state during vertical alignment, as indicated by reference numeral A. The major axis at the time falls in the xy plane) and is horizontally oriented.
Thereafter, as indicated by reference numeral B, the orientation in the in-plane direction of the major axis direction changes and aligns in a certain direction.
In the light control film 10, as indicated by the symbol A, the liquid crystal molecules 18 </ b> A are horizontally aligned in the in-plane direction according to the state during vertical alignment, whereby the transmittance is temporarily reduced to about 1/3 of the saturation value. Stands up (FIG. 19). Thereafter, as indicated by reference numeral B, the light control film 10 is gradually increased and saturated in a period until the orientations of the liquid crystal molecules 18A are aligned.

[Behavior during vibration]
When mounted on the vehicle 130 and used, the light control film 10 vibrates due to traveling of the vehicle 130 and the like, and as a result, the fluctuation in the major axis direction in the vertical orientation becomes much larger than that in the stationary state. Therefore, the direction of the liquid crystal molecules 18A that fall down during horizontal alignment (the direction of the long axis direction) also varies more greatly than when it is stationary. Therefore, in a vehicle, the response speed when changing the transmittance further increases.

In addition, since the magnitude of vibration is different in each part, the magnitude of fluctuation in the major axis direction during vertical alignment varies in various parts of the light control film 10. Thereby, in the light control film 10, the response time concerning the horizontal alignment of the liquid crystal molecules 18A differs in each part, and when the transmittance is changed, a distribution occurs in the transmittance and the transmittance becomes non-uniform.

[This embodiment]
Thus, in the present embodiment, the time until the horizontally aligned liquid crystal molecules 18A are aligned in the direction corresponding to the pretilt is shortened, thereby reducing response speed deterioration and nonuniform transmission.

FIG. 22 is a characteristic curve diagram showing the voltage applied between the transparent electrodes 11 and 16 and the transmittance of the light control film 10 at that time, and corresponds to FIG.
In the present embodiment, the drive voltage V1 of ± 10V is applied after applying the preliminary voltage V2 of about 2.5V for a period of 10 msec.
Although the preliminary voltage is 2.5 V in the present embodiment, the preliminary voltage is not limited to this, and the preliminary voltage is a voltage value in which the angle at which the liquid crystal molecules tilt is 1 degree or more and 5 degrees or less from the normal line of the surface of the light control film 10. If it is.

According to the present embodiment, as shown in the figure, the transmittance is changed in a short time by first applying the preliminary voltage. In FIG. 20, the transmittance is temporarily reduced as described above. However, in the present embodiment, such a temporary decrease in transmittance does not occur. According to the present embodiment, as shown in FIG. 22, the transmittance is saturated at about 20 msec, and the response speed is shorter than that in FIG.

The reason for this is considered as follows.
When the preliminary voltage V2 of about 2.5 V is applied, the liquid crystal molecules 18A slightly fall in the horizontal direction from the normal line of the surface of the light control film 10 corresponding to the preliminary voltage V2. In the comparative embodiment, it is considered that the suppression of individual variations due to the movement of the liquid crystal molecules 18A in the in-plane direction, which is described using the symbol B in FIG. 21, is performed at the time of applying this preliminary voltage V2.
After that, when the driving voltage V1 is applied, the liquid crystal molecules 18A are tilted in the horizontal direction in a state where the variation is already regulated. Therefore, when the drive voltage V1 is applied, it is considered that the movement of the liquid crystal molecules 18A in the in-plane direction is omitted and the response speed is shortened.

[Setting the tilt of liquid crystal molecules]
Here, if the inclination of the liquid crystal molecules 18A when the preliminary voltage V2 is applied is too small, it is difficult to sufficiently improve the response speed.
However, the state in which the preliminary voltage V <b> 2 is applied is a state before the occupant starts operating the transmittance of the light control film 10. Therefore, when the transmittance is minimum (light-shielding) when no voltage is applied to the liquid crystal as in the present embodiment, it is preferable that the light-shielding state is sufficiently maintained even when the preliminary voltage V2 is applied. .

By the way, in the vehicle 130, the passenger is seated, and the direction of the passenger's line of sight is forward for most of the period. Further, in the vehicle 130, it is rare that the passenger looks up from above and visually recognizes the light control film 10 provided on the sunroof 132 from the front.
On the other hand, the VA-type light control film 10 has a characteristic that the transmittance varies depending on the viewing direction.

Therefore, in the present embodiment, the VA system and the characteristics of the vehicle are effectively used to sufficiently improve the response speed and to sufficiently shield the incident light, and further sufficiently as follows. Ensure transmittance.

[Description of angle]
First, the tilt angle of the liquid crystal molecules will be described. FIG. 23 is a diagram illustrating the definition of polar angle and azimuth angle in the single domain method.
FIG. 23A is a schematic cross-sectional view of the light control film 10. The state A shows the state of the liquid crystal molecules 18A when no electric field is generated between the transparent electrodes 11 and 16, and the liquid crystal molecules 18A are in a vertically aligned state in which the major axis direction is the vertical direction. State B shows the direction in which the liquid crystal molecules 18A are inclined due to the generation of an electric field, and the liquid crystal molecules 18A start horizontal alignment so that the major axis direction of the liquid crystal molecules 18A is in the in-plane direction due to the electric field by the transparent electrodes 11 and 16. Yes.
FIG. 23B is a diagram for explaining the polar angle of the liquid crystal molecules 18A. The polar angle is an inclination in the major axis direction of the liquid crystal molecules 18A from the normal direction (thickness direction) of the light control film 10 as illustrated.
FIG. 23C is a diagram for explaining the direction (azimuth angle) in which the liquid crystal molecules 18A are tilted. Here, the traveling direction of the vehicle 130 is assumed to be an azimuth angle 0.

The light control film 10 of this embodiment is a single domain VA light control film 10 that tilts all liquid crystal molecules in the same direction.
FIG. 24 is a diagram illustrating a change in transmittance when the direction (azimuth angle) of the liquid crystal molecules 18A is different in the light control film 10 of the present embodiment.
The tilt angle (azimuth angle) of the liquid crystal molecules 18A is the direction (azimuth angle) in the tilt direction of the liquid crystal molecules 18A when the traveling direction of the vehicle 130 is 0 ° and the light control film 10 is viewed from below. .

[When preliminary voltage is applied]
When a voltage of about 2.5 V is applied between the transparent electrodes 11 and 16 as a reserve voltage, if the transmittance is about 3% or less, the occupant changes the light shielding state so much from the complete light shielding state at 0 V. Since it is felt that almost no light leakage has occurred, it is within the allowable range. Note that it is more preferable that the transmittance is about 1% or less because almost no change in the light shielding state is felt.

As shown in FIG. 24, when the tilting direction (azimuth angle) of the liquid crystal molecules 18A is 0 degree to 90 degrees, the transmittance is 3% or less.
On the other hand, when the direction in which the liquid crystal molecules 18A are tilted (azimuth angle) is 135 degrees or more, the transmittance is higher than 3%, which is not suitable.

[When driving voltage is applied]
When the maximum transmittance is about 25% when the front is viewed from the front, if the maximum transmittance is 22% or more, the passenger can sufficiently feel the increase in the transmittance. For this reason. The allowable range is 22% or more.
When the direction in which the liquid crystal molecules 18A are tilted (azimuth angle) is 45 degrees or more, the transmittance is 22% or more.
On the other hand, when the direction in which the liquid crystal molecules 18A are tilted (azimuth angle) is 30 degrees or more, the maximum transmittance is less than 22%, which is not suitable.

[Preferred range]
FIG. 25 is a view for explaining a preferable range in the direction in which the liquid crystal molecules 18A are tilted in the sixth embodiment. In the VA-type light control film 10 by a single domain that tilts all liquid crystal molecules in the same direction, the tilt direction (azimuth angle) of the liquid crystal molecules 18A is preferably 45 degrees or more and 90 degrees or less (in the figure, diagonal lines). ). In addition, when tilting the liquid crystal molecules in the forward oblique 45 ° direction, it is most efficient in view of the utilization rate of the polarizing plate.

(1) As described above, according to the present embodiment, with respect to the light control film 10 based on the VA method, the transmittance can be changed in a short time (response speed is shortened) by first applying a preliminary voltage.

(2) Moreover, since the response speed of the light control film 10 is shortened, the dispersion | variation in the response time of the liquid crystal molecule 18A can be reduced, thereby making the transmittance non-uniform when used in a vehicle or the like. Can be reduced.

(3) In the VA type light control film 10 by the single domain of this embodiment, the liquid crystal molecules 18A are tilted in a direction (azimuth angle) of 45 degrees or more and 90 degrees or less, thereby applying a preliminary voltage of 2.5 V. The light leakage at the time can be reduced, and the maximum transmittance can be reduced within an allowable range. Furthermore, when the direction in which the liquid crystal molecules are tilted is 45 ° obliquely forward, the utilization rate of the polarizing plate is good.

[Seventh Embodiment]
Next, a seventh embodiment of the present invention will be described. The seventh embodiment is a two-domain configuration in which the liquid crystal layer 18 is separated into two regions, and the liquid crystal molecules 18A of the respective liquid crystal layers 18 are inclined in different directions when moving from vertical to horizontal. Since the other configuration is the same as that of the sixth embodiment, the description of the same configuration is omitted, and the same configuration is described with the same reference numeral.

In the seventh embodiment, the directions in which the liquid crystal molecules 18A are tilted are not all the same, but are tilted in two directions. FIG. 26 is a diagram illustrating the direction in which the liquid crystal molecules 18A are tilted in the seventh embodiment. When the direction in which the liquid crystal molecules 18A1 in the first region are tilted is the first direction, and the direction in which the liquid crystal molecules 18A2 in the second region is tilted is the second direction, it is between the first direction and the second direction. The angle is 90 degrees.
As shown in the figure, the direction passing through the center of the included angle between the first direction and the second direction is the direction (azimuth angle) in which the liquid crystal molecules 18A are tilted. That is, the first direction and the second direction are at 45 degrees from the direction φ.

FIG. 27 is a diagram showing a change in transmittance when the tilting direction of the liquid crystal molecules 18A is different in the light control film 10 of the seventh embodiment.

[When preliminary voltage is applied]
Similar to the sixth embodiment, when a voltage of about 2.5 V is applied between the transparent electrodes 11 and 16 as a preliminary voltage, if the transmittance is about 3% or less, the occupant can completely shield light at 0 V. From the state, since it does not feel that the light shielding state has changed so much and feels that almost no light leakage has occurred, it is set as an allowable range. In this case as well, it is more preferable to set the transmittance to about 1% or less because almost no change in the light shielding state is felt.
When the direction in which the liquid crystal molecules 18A are tilted is 0 to 90 degrees, the transmittance is 3% or less.
On the other hand, when the direction in which the liquid crystal molecules 18A are tilted (azimuth angle) is 120 degrees or more, the transmittance is higher than 3%, which is not suitable.

[When driving voltage is applied]
Similarly to the sixth embodiment, if it is 22% or more, the passenger can sufficiently feel the increase in transmittance. Therefore, the allowable range is 22% or more.
When the direction in which the liquid crystal molecules 18A are tilted (azimuth angle) is 0 degree, 30 degrees, 90 degrees or more, the transmittance is 22% or more.
On the other hand, when the directions (azimuth angles) of the liquid crystal molecules 18A are 45 degrees and 60 degrees, the maximum transmittance is less than 22%, which is not suitable.

[Preferred range]
FIG. 28 is a view for explaining a preferable range of the liquid crystal molecules 18A in the falling direction in the seventh embodiment. As shown in the drawing, in the VA mode light control film 10 having two domains of 90 degrees between each other, the direction in which the liquid crystal molecules 18A are tilted is preferably about 0 to 30 degrees as described above.

(1) As described above, this embodiment also has the same effects as the effects (1) and (2) of the sixth embodiment.

(2) Further, in the VA mode light control film 10 having two domains at intervals of 90 degrees according to the present embodiment, the direction (azimuth angle) in which the liquid crystal molecules 18A are tilted is set to 0 degrees to 30 degrees and 90 degrees. As a result, it is possible to reduce the light-shielding leakage at the time of applying the preliminary voltage of 2.5 V, and to reduce the maximum transmittance within an allowable range.

[Eighth Embodiment]
Next, an eighth embodiment of the present invention will be described.
In the eighth embodiment, the liquid crystal layer 18 is divided into two regions, and the liquid crystal molecules 18A of the respective liquid crystal layers 18 have two domains that are inclined in different directions when moving from the vertical direction to the horizontal direction.
Since the other configuration is the same as that of the sixth embodiment, description of the same configuration is omitted.

In the eighth embodiment, the directions in which the liquid crystal molecules 18A are tilted are not all the same, but are tilted in two directions. FIG. 29 is a diagram illustrating the direction in which the liquid crystal molecules 18A are tilted in the eighth embodiment. When the direction in which the liquid crystal molecules 18A3 in the first region are tilted is the first direction, and the direction in which the liquid crystal molecules 18A4 in the second region is tilted is the second direction, it is between the first direction and the second direction. The angle is 180 degrees. As illustrated, the first direction is a direction in which the liquid crystal molecules 18A are tilted.

FIG. 30 is a diagram showing a change in transmittance when the direction (azimuth angle) of the liquid crystal molecules 18A is different in the light control film 10 of the eighth embodiment.

[When preliminary voltage is applied]
As in the first and seventh embodiments, when a voltage of about 2.5 V is applied between the transparent electrodes 11 and 16 as a reserve voltage, if the transmittance is about 3% or less, Since it does not feel that the light-shielding state has changed so much from the complete light-shielding state and feels that almost no light leakage has occurred, it is set as an allowable range. In this case as well, it is more preferable to set the transmittance to about 1% or less because almost no change in the light shielding state is felt.
When the direction in which the liquid crystal molecules 18A are tilted (azimuth angle) is 45 degrees to 135 degrees, the transmittance is 3% or less.
On the other hand, when the tilting direction (azimuth angle) of the liquid crystal molecules 18A is smaller than 0 degree to 30 degrees or larger than 150 degrees, the transmittance is larger than 3%, which is not suitable.

[When driving voltage is applied]
The maximum transmittance is. If it is 175 or more, the passenger can fully feel the increase in transmittance. For this reason. The allowable range is 22% or more.
When the direction in which the liquid crystal molecules 18A are tilted (azimuth angle) is 45 degrees to 135 degrees, the transmittance is 22% or more.
On the other hand, when the tilt direction (azimuth angle) of the liquid crystal molecules 18A is smaller than 0 degree to 30 degrees or larger than 150 degrees, the transmittance is less than 22%, which is not suitable.

[Preferred range]
FIG. 31 is a diagram for explaining a preferable range of the liquid crystal molecules 18A in the falling direction in the eighth embodiment. As shown in the drawing, in the VA mode light control film 10 having two domains of 180 degrees between each other, the direction in which the liquid crystal molecules 18A are tilted is preferably 45 degrees or more and 135 degrees or less as described above. In addition, when tilting the liquid crystal molecules in the forward oblique 45 ° direction, it is most efficient in view of the utilization rate of the polarizing plate.

(1) As described above, this embodiment also has the same effects as the effects (1) and (2) of the sixth embodiment.

(2) Further, in the VA mode light control film 10 having two domains with an interval of 180 degrees of the present embodiment, the direction in which the liquid crystal molecules 18A tilt (azimuth angle) is 45 degrees or more and 135 degrees or less, In addition to reducing light shielding leakage when applying a 2.5 V preliminary voltage, the maximum transmittance can also be reduced within an allowable range.

[Other Embodiments]
The specific configuration suitable for the implementation of the present invention has been described in detail above. However, the present invention can be variously combined and further modified without departing from the spirit of the present invention. .

DESCRIPTION OF SYMBOLS 1, 31, 200 Light control system 2D, 2U Operator 3, 33 Light control device 4, 34 Controller 5, 35 Driving power generation part 10 Light control film 12, 13 Linearly polarizing plate 12A, 13A Phase difference film 14 Liquid crystal cell 15D Lower laminated body 15U Upper laminated body 16, 25 Base material 18 Liquid crystal layer 18A Liquid crystal molecule 21, 26 Transparent electrode 21 Dimming system 22 Spacer 23, 27 Alignment layer 29 Sealing material 37 Switch circuit 130 Vehicle 132 Sunroof 140 Controller

Claims (20)

1. A light control film for controlling the transmitted light by aligning the liquid crystal of the liquid crystal cell sandwiched by the linear polarizing plates by the VA method;
   A light control device having a drive power generation unit that outputs a rectangular wave signal to the light control film;
   The light control device is:
   By varying the amplitude of the rectangular wave signal in response to the operation of the operation element, the transmittance of the light control film is varied,
   A dimming system that gradually increases the amplitude of the rectangular wave signal when increasing the amplitude of the rectangular wave signal.
2. The light control system according to claim 1, wherein a time for gradually increasing the amplitude of the rectangular wave signal is 3 seconds or less.
3. The light control device is:
   The dimming system according to claim 1 or 2, wherein the amplitude of the rectangular wave signal is gradually increased by sequentially increasing the amplitude in a plurality of cycles of the rectangular wave signal.
4. The light control device is:
   3. The dimming system according to claim 1, wherein the amplitude of the rectangular wave signal is gradually increased by gradually increasing the amplitude in each period of the rectangular wave signal by a time constant circuit.
5. The light control device is:
   The rectangular wave signal is emitted to the light control film through a resistor,
   The time constant circuit is
   The light control system according to claim 4, wherein the light control system is formed by at least the resistor and a capacitance of the light control film.
6. A light control film for controlling the transmitted light by aligning the liquid crystal of the liquid crystal cell sandwiched by the linear polarizing plates by the VA method;
   A light control device having a drive power generation unit that outputs a rectangular wave signal to the light control film;
   The light control device is:
   By varying the amplitude of the rectangular wave signal in response to the operation of the operation element, the transmittance of the light control film is varied,
   The light control film is
   A first laminate in which a transparent electrode and an alignment layer are arranged on a substrate made of a transparent film material;
   A second laminate in which a transparent electrode and an alignment layer are arranged on a substrate made of a transparent film material;
   A liquid crystal layer sandwiched between the first and second laminates,
   Supplying the rectangular wave signal to the transparent electrodes of the first and second laminates to control the transmitted light;
   A dimming system further comprising a time constant circuit that gradually increases the amplitude of the rectangular wave signal applied to the transparent electrodes of the first and second laminates at least when the amplitude of the rectangular wave signal is increased.
7. The time constant circuit is
   The light control system according to claim 6, wherein the light control system is formed by at least a resistor and a capacitance between the transparent electrodes of the first and second stacked bodies.
8. A light control device having a drive power generation unit that outputs a rectangular wave signal to a light control film,
   The light control film is
   Control the transmitted light by aligning the liquid crystal of the liquid crystal cell sandwiched by the linear polarizing plate by the VA method,
   The light control device is:
   By varying the amplitude of the rectangular wave signal in response to the operation of the operation element, the transmittance of the light control film is varied,
   A dimming device that gradually increases the amplitude of the rectangular wave signal when increasing the amplitude of the rectangular wave signal.
9. In the light control film for controlling the transmitted light by aligning the liquid crystal of the liquid crystal cell sandwiched by the linear polarizing plates by the VA method,
   A first laminate in which a transparent electrode and an alignment layer are arranged on a substrate made of a transparent film material;
   A second laminate in which a transparent electrode and an alignment layer are arranged on a substrate made of a transparent film material;
   A liquid crystal layer sandwiched between the first and second laminates,
   Controlling transmitted light according to a rectangular wave signal applied to the transparent electrodes of the first and second laminates,
   The light control film which increases gradually the amplitude of the said rectangular wave signal applied to the transparent electrode of the said 1st and 2nd laminated body by a time constant circuit when the amplitude of the said rectangular wave signal increases.
10. A light control film for controlling the transmitted light by aligning the liquid crystal of the liquid crystal cell sandwiched by the linear polarizing plates by the VA method;
    A light control device having a drive power generation unit that outputs a rectangular wave signal to the light control film;
    The light control device is:
    By varying the amplitude of the rectangular wave signal in response to the operation of the operation element, the transmittance of the light control film is varied,
    A dimming system that applies a voltage having a certain value with a certain polarity in advance for a certain period of time before increasing the amplitude of the rectangular wave signal.
11. The predetermined period is 5 milliseconds or more;
    The light control system according to claim 10.
12. The predetermined period is 100 milliseconds or less.
    The light control system according to claim 10.
13. In the drive method of the light control film which controls the transmitted light by orienting the liquid crystal of the liquid crystal cell sandwiched between the linear polarizing plates by the VA method,
    In response to the operation of the operation element, by changing the amplitude of the rectangular wave signal by the rectangular wave signal output to the light control film, the transmittance of the light control film is changed,
    A method for driving a light control film, wherein the amplitude of the rectangular wave signal is gradually increased when increasing the amplitude of the rectangular wave signal.
14. A light control film having a liquid crystal layer in which liquid crystal molecules are disposed, and two planar electrodes disposed so as to face each other and sandwich the liquid crystal layer;
    A control unit that applies a driving voltage between the electrodes and controls the transmittance of the light control film according to the value of the driving voltage;
    The controller is
    Prior to application of the drive voltage, a preliminary voltage smaller than the drive voltage is applied between the electrodes,
    Dimming system.
15. The preliminary voltage is a voltage for tilting the liquid crystal molecules from 1 degree to 5 degrees from the normal line of the surface of the light control film.
    The light control system of Claim 14.
16. The light control film is disposed on a sunroof of a vehicle,
    The azimuth angle at which the liquid crystal molecules fall when the light control film is viewed from below with the traveling direction of the vehicle being 0 ° is 45 ° or more and 90 ° or less,
    The light control system of Claim 14 or 15.
17. The light control film is disposed on a sunroof of a vehicle,
    The liquid crystal layer includes a first region and a second region in which the liquid crystal molecules are tilted in two directions different from each other by 90 degrees by the driving voltage,
    When the traveling direction of the vehicle is 0 °, and the light control film is viewed from below, the azimuth angles of the liquid crystal molecules disposed in the first region are from 0 degrees to 30 degrees and 90 degrees. is there,
    The light control system of Claim 14 or 15.
18. The light control film is held on a sunroof of a vehicle,
    The liquid crystal layer includes a first region and a second region in which the liquid crystal molecules are tilted in two directions different from each other by 180 degrees by the driving voltage,
    When the traveling direction of the vehicle is 0 ° and the light control film is viewed from below, the azimuth angle of the liquid crystal molecules disposed in the first region is tilted,
    The light control system according to claim 14 or 15, wherein the light control system is 45 degrees or less and 130 degrees or less.
19. A light control film having a liquid crystal layer in which liquid crystal molecules are disposed, and two planar electrodes disposed to face each other and sandwich the liquid crystal layer, and attached to a sunroof;
    A control unit for controlling the transmittance of the light control film according to the value of the drive voltage applied between the electrodes,
    The vehicle, wherein the control unit applies a reserve voltage smaller than the drive voltage between the electrodes prior to application of the drive voltage.
20. In a light control film having a liquid crystal layer in which liquid crystal molecules are disposed and two planar electrodes disposed so as to face each other and sandwich the liquid crystal layer, the value of the drive voltage applied between the electrodes A drive method of the light control film for controlling the transmittance of the light control film,
    Prior to application of the drive voltage, a preliminary voltage smaller than the drive voltage is applied between the electrodes,
    Driving method of light control film.

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