JP6128269B1 - Light control film - Google Patents

Abstract

Provided is a light control film capable of gradually changing in-plane transmissivity and giving bright and dark gradations in the surface. A light control film of the present invention is provided on a first electric distance electrode and a second electric distance electrode that are opposed to each other, and on the first electric distance electrode. A power feeding unit 20A that applies a voltage between one electric distance electrode 22A and the second electric distance electrode 22B, and is disposed between the first electric distance electrode 22A and the second electric distance electrode 22B. A light-modulating material 14 that changes the transmittance according to the voltage applied between the first electric distance electrode 22A and the second electric distance electrode 22B, and at a position different from the power feeding unit 20A. The first electrical distance electrode 22A and the second electrical distance electrode 22B are electrically connected. [Selection] Figure 3

Description

  The present invention relates to a light control film that can be used, for example, in an electronic blind that is attached to a window to control the transmission of extraneous light.

Conventionally, for example, a light control film that can be used for an electronic blind or the like that is attached to a window to control the transmission of external light has been proposed (Patent Documents 1 and 2). One such light control film uses liquid crystal.
A light control film using liquid crystal is produced by sandwiching a liquid crystal material with a transparent plate material including a transparent electrode to produce a liquid crystal cell, and sandwiching the liquid crystal cell with a linear polarizing plate. This light control film changes the orientation of the liquid crystal by changing the electric field applied between the transparent electrodes, and controls the amount of transmitted extraneous light.

  Conventionally, when a voltage is applied between transparent electrodes in such a light control film, the transmittance changes according to the voltage, but the light transmittance in the plane of the light control film is substantially constant.

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

However, in recent years, there has been a demand for a light control film that can diversify the use of the light control film, gradually change the in-plane transmittance, and provide a light and dark gradation in the surface.
This invention is made | formed in view of such a condition, and it aims at providing the light control film which can change the transmittance | permeability in a surface gradually, and can attach a light and dark gradation in a surface.

Specifically, the present invention provides the following.
(1) a first electrode and a second electrode arranged to face each other;
Two electrodes provided on the first electrode and provided with a power feeding section for applying a voltage between the first electrode and the second electrode;
A light-modulating material disposed between the first electrode and the second electrode, the light-modulating material changing transmittance by the voltage applied between the electrodes of the first electrode and the second electrode; With
A light control film, wherein the first electrode, the second electrode, and the electrodes are electrically connected at a position different from the power feeding unit.

  (2) The light control film according to (1), wherein a resistance member is disposed between the first electrode and the second electrode.

  (3) The light control film according to (2), wherein the resistance value of the resistance member is variable.

  (4) In (1) to (3), the power feeding section is provided on one end side of the first electrode, and on the other end side of the first electrode and on the other end side of the second electrode. A light control film in which the electrodes are electrically connected.

  (5) In (1) to (4), the said electric power feeding part is a light control film provided in multiple places.

  (6) The light control film according to (1) to (5), wherein the first electrode, the second electrode, and the electrode are electrically connected at a plurality of locations different from the power feeding unit.

  ADVANTAGE OF THE INVENTION According to this invention, the light control film which can change the transmittance | permeability in a surface gradually, and can attach a bright and dark gradation in a surface can be provided.

It is sectional drawing which shows a light control film. It is a flowchart which shows the manufacturing process of a light control film. It is a figure explaining the voltage applied between electrodes. The state of the electric potential of a 2nd electrode and a 1st electrode is shown. It is the graph which showed the relationship between the transmittance | permeability of a light control film, and an electrical potential difference.

[Light control film]
Drawing 1 is a sectional view showing light control film 10 of an embodiment. The light control film 10 is used, for example, by being attached to a portion where light control is to be performed or used for laminated glass. The case where it is used by being attached to a part to be dimmed is, for example, a case where it is placed on the rear window of a vehicle, a window glass of a building, a showcase, an indoor transparent partition, etc. to switch between transmission and opaque.

The light control film 10 is a light control film that controls transmitted light using liquid crystal, and the liquid crystal cell 15 is sandwiched between the second laminate 13 and the first laminate 12 each having a film shape. Is produced by sandwiching the liquid crystal cell 15 by linearly polarizing plates 16 and 17.
In the embodiment, the liquid crystal layer 14 is driven by a VA (Virtual Alignment) method, but is not limited to this, and various methods such as a TN (Twisted Nematic) method, an IPS (In-Place-Switching) method, and the like. A driving method can be applied.
The VA method is a method in which the alignment of liquid crystal is changed between vertical alignment and horizontal alignment to control transmitted light. When no electric field is applied, the liquid crystal layer 14 is sandwiched between the vertical alignment layers by vertically aligning the liquid crystal. Thus, the liquid crystal cell 15 is configured, and the liquid crystal material is horizontally aligned by applying an electric field.

In the light control film 10, a spacer 24 for keeping the thickness of the liquid crystal layer 14 constant is provided in the first laminate 12 and / or the second laminate 13. The linear polarizing plates 16 and 17 are respectively provided with retardation films 18 and 19 for optical compensation on the liquid crystal cell 15 side.
The laminates 12 and 13 are formed by sequentially forming the first electrode 22A, the second electrode 22B, and the alignment layers 23A and 23B on the base materials 21A and 21B, respectively. The retardation films 18 and 19 may be omitted as necessary. Moreover, you may manufacture the light control film 10 by a guest host system, and in this case, a linearly-polarizing plate is arrange | positioned at one or both of a liquid crystal cell as needed.

The light control film 10 is configured to control the transmission of extraneous light by changing the voltage applied to the first electrode 22A and the second electrode 22B, and to switch the state between a transparent state and a non-transparent state. In the present embodiment, an example in which the liquid crystal layer 14 is driven by so-called normally black will be described. However, the present invention is not limited to this, and the liquid crystal layer 14 may be driven by normally white. Further, in the case of the IPS method, it goes without saying that the first electrode 22A and the second electrode 22B are manufactured together on the alignment layer 23A or 23B side, and the laminates 12 and 13 are configured to correspond to this. Will be.
Note that normally black is a structure in which the transmittance is minimized when a voltage is not applied to the liquid crystal, resulting in a black screen. Normally white is a structure in which the transmittance is maximized and transparent when no voltage is applied to the liquid crystal.

  When the light control film 10 is used by being attached to, for example, a window glass of a building, a showcase, an indoor transparent partition, etc., the linear polarizing plate 16 and / or 17 on the side opposite to the liquid crystal cell 15 is used. A protective layer such as a hard coat layer is provided on the surface.

[Base material]
Various transparent film materials having flexibility applicable to the liquid crystal cell 15 can be applied to the base materials 21A and 21B. In this embodiment, a film material made of polycarbonate in which a hard coat layer is manufactured on both surfaces. Applies.

[electrode]
The first electrode 22A and the second electrode 22B can apply an electric field to the liquid crystal layer 14 and can adopt various configurations that are perceived as transparent. In the present embodiment, ITO that is a transparent electrode material is used. A transparent conductive film made of (Indium Tin Oxide) is formed on the entire surface of the base materials 21A and 21B. As described above, in the IPS method or the like, the electrode is manufactured by being patterned in a desired shape.

[Alignment layer]
The alignment layers 23A and 23B are formed of a photo-alignment layer. 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. In this embodiment, for example, a photodimerization type material is used. The photodimerization type material is described in “M. Schadt, K. Schmitt, V. Kozinkov and V. Chigrinov: Jpn. J. Appl. Phys., 31, 2155 (1992)”, “M. Seiberle and A. Schuster: Nature, 381, 212 (1996).

Instead of the photo-alignment layer, it may be produced by a rubbing process. In this case, the alignment layers 23A and 23B are manufactured by manufacturing various material layers applicable to the alignment layer such as polyimide, and then manufacturing a fine line-shaped uneven shape on the surface of the material layer by rubbing using a rubbing roll. Formed.
Instead of the alignment layer and the photo-alignment layer by such a rubbing treatment, a fine line-shaped uneven shape produced by the rubbing treatment may be produced by a shaping treatment to produce the orientation layer.

[spacer]
The spacer 24 is provided in order to define the thickness of the liquid crystal layer 14, and various resin materials can be widely applied. In this embodiment, the spacer 24 is manufactured by a photoresist. The spacer 24 is manufactured by applying a photoresist on the base material 21B formed by manufacturing the second electrode 22B, and exposing and developing. The spacer 24 may be provided in the first stacked body 12 or may be provided in both the first stacked body 12 and the second stacked body 13. The spacer 24 may be provided on the alignment layer 23B. As the spacer, a so-called bead spacer may be applied.

[Liquid crystal layer]
Various liquid crystal materials applicable to this type of light control film can be widely applied to the liquid crystal layer 14. Specifically, for the liquid crystal layer 14, for example, a liquid crystal compound described in JP-A No. 2003-366484 can be used. Moreover, as a marketed product, liquid crystal materials, such as Merck MLC2166, can be applied, for example. In the case of the guest-host method, the liquid crystal layer 14 is mixed with a liquid crystal material and a dye for dimming, but a mixture of a liquid crystal material and a dye proposed for the guest-host method can be widely applied. it can. In the liquid crystal cell 15, a sealing material 25 is disposed so as to surround the liquid crystal layer 14, and leakage of liquid crystal is prevented by the sealing material 25. Here, for example, an epoxy resin, an ultraviolet curable resin, or the like can be applied to the sealing material 25.

[Manufacturing process]
FIG. 2 is a flowchart showing the manufacturing process of the light control film 10. In the liquid crystal cell 15, the second stacked body 13 is manufactured in the second stacked body manufacturing step SP2. In the second laminate manufacturing process SP2, in the electrode manufacturing process SP2-1, the second electrode 22B made of ITO is manufactured on the base material 21B by sputtering or the like. In the subsequent spacer manufacturing step SP2-2, the coating liquid (photoresist) relating to the spacer 24 is applied, and then the spacer 24 is manufactured by drying, exposing and developing. Subsequently, in the alignment layer manufacturing step SP2-3, after coating and drying the coating liquid related to the alignment layer 23B, the alignment direction of the liquid crystal molecules is set by irradiation with ultraviolet rays, whereby the alignment layer 23B is manufactured. . Thus, in this embodiment, the second laminate 13 is manufactured.

  In the manufacturing process of the light control film 10, in the subsequent first laminate manufacturing process SP3, the first laminate 12 is manufactured in the same manner as the second laminate manufacturing process SP2. That is, in the first laminate manufacturing process SP3, the first electrode 22A made of ITO is manufactured on the base material 21A by sputtering or the like, and after the coating liquid related to the alignment layer 23A is applied and dried, the liquid crystal molecules are irradiated by ultraviolet irradiation. By setting the alignment direction, the alignment layer 23A is manufactured, and the first laminate 12 is manufactured by these.

  In this manufacturing process, in the subsequent liquid crystal cell manufacturing process SP4, after applying the sealing material 25 in a frame shape using a dispenser, a liquid crystal material is disposed in the frame-shaped portion, and the first laminated body 12, The laminated body 13 is laminated and pressed to cure the sealing material 25 by ultraviolet irradiation or the like, thereby manufacturing the liquid crystal cell 15. In the arrangement of the liquid crystal material, the first stacked body 12 and the second stacked body 13 are stacked so that the first stacked body 12 and the second stacked body 13 are stacked first. It may be arranged in the gap.

  The light control film 10 is formed by being laminated with the linear polarizing plates 16 and 17 in the subsequent lamination step SP5. The liquid crystal cell 15 is provided in the form of a long film in which the base materials 21A and 21B are wound on a roll, and all of these processes SP2 to SP5 or a part of these processes SP2 to SP5 are based on the roll. It is executed while the materials 21A and 21B are pulled out and conveyed. As a result, each step of the liquid crystal cell 15 is executed by a process one by one from an intermediate step as necessary.

[Voltage application]
FIG. 3 is a diagram illustrating a voltage applied between the first electrode 22A and the second electrode 22B. The first electrode 22A and the second electrode 22B are not limited to this, but are rectangular in this embodiment. Conductive portions 221A and 222A are provided by silver paste or the like at both ends in the longitudinal direction of the first electrode 22A. Conductive portions 221B and 222B are provided by silver paste or the like at both ends in the longitudinal direction of the second electrode 22B. These conductive portions 221A, 222A, 221B, and 222B extend in the short direction at the longitudinal ends of the first electrode 22A and the second electrode 22B.

The conductive portion 221A at one end of the first electrode 22A is provided with a power feeding portion 20A to which the power source 20 is attached, and a predetermined voltage E ₀ is applied from the power feeding portion 20A to the conductive portion 221A. The magnitude of the voltage E ₀ can be varied by adjusting the power supply 20. In this embodiment, the voltage is a direct current, but is not limited to this, and may be an alternating current.

The conductive portion 221B at one end of the second electrode 22B is grounded. A three-way switch 30 is connected to the conductive portion 222A at the other end of the first electrode 22A. One contact P1 selected by the three-way switch 30 is connected to one end of the variable resistor 31, and the other end of the variable resistor 31 is connected to the conductive portion 222B of the other end of the second electrode 22B. The other contact P2 selected by the three-way switch 30 is connected to the conductive portion 222B at the other end of the second electrode 22B without passing through a resistor.
In the present embodiment, the conductive portion 222A at the other end of the first electrode 22A is connected to the conductive portion 222B at the other end of the second electrode 22B by the three-way switch 30 as described above. The embodiment has been described in which it is selectively connected to either the side connected to the conductive portion 222B at the other end of the second electrode 22B without the variable resistor 31 interposed therebetween. However, the present invention is not limited to this.
The conductive portion 222A at the other end of the first electrode 22A and the conductive portion 222B at the other end of the second electrode 22B may be in direct contact, for example, without passing through the three-way switch 30, and are bonded with a conductive paste. Alternatively, they may be connected by a conductive wire, connected via a resistor, or connected via a variable resistor.

FIG. 4 shows the potential states of the first electrode 22A and the second electrode 22B when the voltage E ₀ is applied to the conductive portion 221A of the first electrode 22A and the conductive portion 221B of the second electrode 22B is connected to the ground. Show.

When the three-way switch 30 is not connected to any of the contacts P1 and P2 and is open, the resistance becomes infinite. Therefore, as shown by a dotted line in FIG. ₀ is substantially constant, and the second electrode 22B has a potential of 0.
When the three-way switch 30 is connected to the contact P2 in FIG. 3, since the resistance value R is substantially zero, RI = 0, and the shape shown by the one-dot chain line in FIG.
When the three-way switch 30 is connected to the contact P <b> 1 in FIG. 3, RI varies with the resistance value R of the variable resistor 31. The resistance value R of the variable resistor 31 can be adjusted with a knob, for example. As the resistance value R of the variable resistor 31 increases, the potential difference RI between the conductive portion 222A of the first electrode 22A and the conductive portion 222B of the second electrode 22B increases. When the resistance value R of the variable resistor decreases, the potential difference RI between the conductive portion 222A of the first electrode 22A and the conductive portion 222B of the second electrode 22B decreases.

As shown in the drawing, the potential E ₁ (x) of the first electrode 22A is E ₀ that is fed in the conductive portion 221A on one end side, but decreases as it proceeds in the direction of the conductive portion 222A on the other end side.
Then, at the position of the conductive portion 222A (position at a distance L from one end side), the potential decreases by RI (R: resistance value of the variable resistor, I: current flowing through the variable resistor).
The potential E ₂ (x) of the conductive portion 222B on the other end side of the second electrode 22B is a potential that is lowered from the RI, and then decreases toward the conductive portion 221B on the one end side. Become.

At the position of distance x from one end of the first electrode 22A and second electrode 22B, the potential difference between the potential _E 2 (x) of the potential _E 1 (x) and the second electrode 22B of the first electrode 22A (voltage) E (x) is expressed as follows.

E (x) = E ₁ (x) −E ₂ (x) (1)

Here, if the resistance value of the entire length of the first electrode 22A is R ₁ and the resistance value of the entire length of the second electrode 22B is R ₂ ,
E ₁ (x) = E ₀ −R ₁ Ix / L (2)
E ₂ = R ₂ Ix / L (3)
E ₀ = I (R + R ₁ + R ₂ ) (4)
So

If (1) is transformed by substituting (2) to (4), etc.,

E (x) = E ₀ −E ₀ {(R ₁ + R ₂ ) / (R + R ₁ + R ₂ )} x / L

It becomes.

  Here, FIG. 5 is a graph showing the relationship between the transmittance T of the light control film 10 and the potential difference E (x). Since the inclination of the liquid crystal changes depending on the potential difference E (x), the transmittance T of the light control film 10 changes according to the change of the potential difference E (x) as shown in the figure.

  In the present embodiment, when the switch 30 is connected to the contact P1, the potential difference E (x) between the first electrode 22A and the second electrode 22B in the light control film 10 is expressed by the formula (1) according to the position x in the longitudinal direction. It changes like '. Therefore, the transmittance T of the light control film 10 can be gradually changed in the longitudinal direction (a gradation is added or a gradation is added). Further, the change ratio can be changed by changing the resistance value R, and the gradation can be changed to a desired shading.

Further, as shown in FIG. 5, the relationship between the transmittance T and the potential difference E of the light control film 10 is not linear, and the transmittance is 0 when the potential difference E (x) is from 0 to V _0. more than ₀ a rising abruptly, gradually becomes gentle slope exceeds V _1, is substantially constant.
That is, since the variation of the transmittance T is large between V ₀ and V ₁ , the potential difference E (x) shown in FIG. 4 is changed in the range of V ₀ to V ₁ , thereby transmitting the light. The rate T can be varied more greatly. That is, the gradation width can be increased, in other words, the shade width can be increased.

That is,

V ₀ ≦ E (x) ≦ V ₁

And E (x) varies between E ₀ -E ₀ (R ₁ + R ₂ ) / (R + R ₁ + R ₂ ) = IR and E ₀ ,

IR ≦ V ₀ <V ₁ ≦ E ₀

It is.

If this is transformed,

R ≦ V ₀ / I = V ₀ (R + R ₁ + R ₂ ) / E ₀
E ₀ R ≦ V ₀ (R + R ₁ + R ₂ )
(E ₀ −V ₀ ) R ≦ V ₀ (R ₁ + R ₂ )
R ≦ V ₀ (R ₁ + R ₂ ) / (E ₀ −V ₀ )

Therefore,

0 ≦ R ≦ V ₀ (R ₁ + R ₂ ) / (E ₀ −V ₀ )

  According to the present embodiment, by setting the resistance value R within this range, the amount of change in the transmittance T with respect to the change in voltage can be increased, and the gradation width of the in-plane gradation in the light control film 10 is increased. can do. However, the range of the resistance value R is not limited to the above formula.

(Deformation)
(1) Although the VA liquid crystal light control film has been described as an embodiment of the present invention, the present invention is not limited to this, and may be another system capable of adjusting the light control amount by a potential difference.
For example, a TN method (twisted nematic liquid crystal) may be used as a liquid crystal light control film other than the VA method. In the TN system, when the voltage is OFF, the liquid crystal molecules are aligned horizontally in the TN system, and the light is allowed to pass through and the screen becomes “white”. When voltage is gradually applied, the liquid crystal molecules rise vertically, blocking the light and blacking the screen.

Moreover, as what uses liquid crystal other than a liquid crystal, for example, EC system, SPD system, and PDLC system light control film may be used.
A light control film using an EC system (Electrochromic) has a structure in which a light control layer (electrolyte layer) is sandwiched between a pair of electrodes. Depending on the potential difference between the electrodes, the color of the light control layer changes between transparent and dark blue using an oxidation-reduction reaction.
The light control film using the SPD method (Suspended Particle Device) is normally colored in dark blue using the orientation of fine particles, but it changes to transparent when a voltage is applied, and changes to the original dark blue when the voltage is turned off. It is a return, and the shade can be adjusted by the voltage.
The light control film using the PDLC method (Particle Dispersed Liquid Crystal) is a liquid crystal layer in which a network structure of a special polymer is formed. Due to the action of the polymer network, the arrangement of liquid crystal molecules is irregular. Induces and scatters light. When a voltage is applied to align the liquid crystal molecules in the electric field direction, the light is not scattered and becomes transparent.
Light control film

(2) In this embodiment, a description has been given of normally black having low transmittance when no voltage is applied. However, normally white may be used depending on the type of liquid crystal. As described above, normally black is a structure in which the transmittance is minimized and a black screen is obtained when no voltage is applied to the liquid crystal. Normally white is a structure in which the transmittance is maximized and transparent when no voltage is applied to the liquid crystal.

(3) In the present embodiment, power is supplied from one side of the rectangular electrode, and a resistor is connected to the opposite side via a three-pole switch. However, the present invention is not limited to this. For example, the power supply may be performed from one point instead of the entire side. In this case, the potential line has an annual ring shape.
(4) Further, the other side to which power is supplied from one side of the rectangular electrode and the resistor is connected may be an adjacent side instead of an opposite side. Furthermore, the side to which power is fed and the side to which the resistor is connected may be two or more sides instead of one side.
(5) In the present invention, the current applied between the electrodes is a direct current. However, the present invention is not limited to this and may be an alternating current.

  When the second conductive portion 222B of FIG. 3 is grounded, the potential gradient of the first electrode 22A exists, but the potential gradient of the second electrode 22B disappears and becomes a constant voltage (ground). When such a connection method is used, a phenomenon occurs in which gradation is not added when viewed from an oblique direction. However, even in this case, when viewed from the front direction, the gradation can be added within the surface.

  Further, in the above-described embodiment, the case where the liquid crystal cell is sandwiched between the linear polarizing plates to form the light control film is described. However, the present invention is not limited to this, and the linear polarizing plate using the liquid crystal layer of the guest-host type liquid crystal is used. The present invention can also be widely applied to the case where the light control film is constituted by omitting.

  As mentioned above, although the specific structure suitable for implementation of this invention was explained in full detail, this invention can be variously changed in the range which does not deviate from the meaning of this invention.

DESCRIPTION OF SYMBOLS 10 Light control film 12 1st laminated body 13 2nd laminated body 14 Liquid crystal layer 15 Liquid crystal cell 16, 17 Linearly polarizing plate 18, 19 Phase difference film 20 Power supply 21A, 21B Base material 22A 1st electrode 22B 2nd electrode 23A , 23B Alignment layer 24 Spacer 25 Sealing material 30 Three-way switch 31 Variable resistance 221A, 221B, 222A, 222B Conductive part

Claims (4)

A first electrode and a second electrode arranged opposite to each other;
A power feeding unit that is provided on the first electrode and applies a voltage between the first electrode and the second electrode;
A light-modulating material that is disposed between the first electrode and the second electrode, and that changes transmittance by the voltage applied between the first electrode and the second electrode; Prepared,
The first electrode and the second electrode are electrically connected at a position different from the power feeding unit ,
A resistance member is disposed between the first electrode and the second electrode,
The light control film whose resistance value of the said resistance member is variable . A first electrode and a second electrode arranged opposite to each other;
A power feeding unit that is provided on the first electrode and applies a voltage between the first electrode and the second electrode;
A light-modulating material that is disposed between the first electrode and the second electrode, and that changes transmittance by the voltage applied between the first electrode and the second electrode; Prepared,
The first electrode and the second electrode are electrically connected at a position different from the power feeding unit ,
The light control film which the said electric power feeding part is provided in the one end side of the said 1st electrode, and the other end side of the said 1st electrode and the other end side of the said 2nd electrode are electrically connected . A first electrode and a second electrode arranged opposite to each other;
A power feeding unit that is provided on the first electrode and applies a voltage between the first electrode and the second electrode;
A light-modulating material that is disposed between the first electrode and the second electrode, and that changes transmittance by the voltage applied between the first electrode and the second electrode; Prepared,
The first electrode and the second electrode are electrically connected at a position different from the power feeding unit ,
The said electric power feeding part is a light control film provided in several places . A first electrode and a second electrode arranged opposite to each other;
A power feeding unit that is provided on the first electrode and applies a voltage between the first electrode and the second electrode;
A light-modulating material that is disposed between the first electrode and the second electrode, and that changes transmittance by the voltage applied between the first electrode and the second electrode; Prepared,
The first electrode and the second electrode are electrically connected at a position different from the power feeding unit ,
The light control film in which the first electrode and the second electrode are electrically connected at a plurality of locations different from the power feeding unit .

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