TW201940947A - Light control film - Google Patents

Abstract

As a light control film that is capable of improving short circuit prevention properties, while being capable of simplifying the terminal formation work, the present invention provides a light control film that is provided with: a first substrate 1 which has insulating properties and light transmitting properties; a plurality of pairs of linear electrodes 2A, 2B which are formed on one surface of the first substrate 1; a liquid crystal layer 3 which is superposed on the electrode 2A, 2B formation surface of the first substrate 1, and which is formed from a composite material of a polymer and a liquid crystal; and a second substrate 4 which is superposed on the surface of the liquid crystal layer 3, and which has insulating properties and light transmitting properties.

Description

Dimming film

The invention relates to a light control film, which is attached to a transparent plate such as window glass and adjusts the amount of light transmitted through the transparent plate.

Conventionally, as a light control film attached to, for example, a window glass and adjusting the amount of light transmitted through the window glass, a light control film using a liquid crystal layer composed of a polymer and a liquid crystal composite material has been proposed (for example, refer to Patent Document 1). This dimming film includes a pair of light-transmitting substrates facing each other with a gap therebetween, a planar transparent electrode formed on each of the opposite inner surfaces of the light-transmitting substrates, and the above-mentioned sandwiched between the transparent electrodes. Liquid crystal layer.

Then, by changing the voltage applied to the opposing transparent electrodes, the electric field generated between the opposing transparent electrodes (longitudinal) can be changed, and the orientation of the liquid crystal in the liquid crystal layer can be changed to adjust the transmission. The amount of light of the light control film.
[Xizhi technical literature]
[Patent Literature]

Patent Document 1: International Publication No. 2010/100807

[Problems to be solved by the invention]

However, in the conventional light control film described above, the transparent electrodes are opposed to each other with the liquid crystal layer interposed therebetween, and therefore these transparent electrodes are easily short-circuited. Therefore, it is necessary to prevent the short circuit by making the thickness of the liquid crystal layer between the transparent electrodes greater than a certain thickness. In addition, since each transparent electrode is located inside the dimming film, it is necessary to perform a process of forming a terminal exposed on the surface of the dimming film for a terminal for supplying a voltage to each of the transparent electrodes. Installation, it is necessary to perform terminal forming processing on both sides of the light control film. Therefore, there is still room for improvement in these areas.

The present invention has been made in view of such circumstances, and an object thereof is to provide a dimming film, which can improve the short-circuit prevention performance and simplify the terminal forming processing operation.
[Means for solving problems]

In order to achieve the above-mentioned object, the light-adjusting film of the present invention employs a structure including a first substrate having insulation and light transmission properties, a pair or a pair of linear electrodes formed on one side of the first substrate, and A liquid crystal layer composed of a polymer and a liquid crystal composite material laminated on the electrode formation surface of the first substrate.

In order to improve the short-circuit prevention performance and simplify the terminal formation processing operation, the inventors of the present case have made intensive studies on the structure of a light-adjusting film using a liquid crystal layer composed of a polymer and a liquid crystal composite material. In the course of his research, he focused on further research on electrodes. As a result, it was found that as long as the electrodes are formed linearly in a pair or a plurality of pairs, the amount of transmitted light can be adjusted even if the electrodes are formed only on one side of a substrate. In addition, it was found that if the linear electrode is formed on only one side of a substrate in this way, the short-circuit prevention performance can be improved, and the terminal forming process can be performed on only one substrate.

That is, in the light-adjusting film of the present invention, if a voltage is applied to each pair of linear electrodes, an electric field is generated in parallel (toward the lateral direction) with the substrate plate surface, and the liquid crystal is changed by the influence of the electric field. Orientation of liquid crystal in the layer. Then, the amount of light transmitted through the light control film can be adjusted by changing the orientation of the liquid crystal.
[Compared with the efficacy of the prior art]

The light-adjusting film of the present invention is formed by forming a pair or a plurality of pairs of linear electrodes on one side of a first substrate having insulation and light transmission properties, and laminating a polymer and a liquid crystal on the electrode-forming surface of the first substrate. Liquid crystal layer made of composite material. In this way, since the electrodes are not opposed to each other but are formed on a single substrate, short-circuit prevention performance can be improved, and reliability as a dimming film can be improved. Next, it is not necessary to thicken the liquid crystal layer in order to prevent a short circuit, and the width of the liquid crystal layer can be increased with a large degree of freedom in setting the thickness. Therefore, the liquid crystal layer can be made thin, and the light control film can be made thin. Furthermore, since the electrode is formed on a single substrate, the terminal forming process for the terminal for supplying voltage to the electrode is exposed on the surface of the dimming film, and only needs to be performed on one side of the dimming film, which can simplify the formation of the terminal Processing operations.

In particular, when a second substrate having insulating and translucent properties is laminated on the surface of the liquid crystal layer on the side opposite to the first substrate, the surface of the liquid crystal layer on which the second substrate abuts can be protected. Therefore, stable dimming can be performed for a long period of time.

In addition, when the electrodes are formed by printing, the linear electrodes can be made finer, and the degree of freedom in design is greatly increased.

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 (a) is a top view showing a first embodiment of the light control film of the present invention, and FIG. 1 (b) is a sectional view taken along line X-X of FIG. 1 (a). The dimming film in this embodiment includes: a first substrate 1 having insulation and light transmission properties; a plurality of pairs of linear electrodes 2A and 2B formed on one side of the first substrate 1; a liquid crystal layer 3 made of a polymer And a liquid crystal composite material and laminated on the formation surfaces of the electrodes 2A and 2B of the first substrate 1; and a second substrate 4 having insulation and light transmission properties and laminated on the surface of the liquid crystal layer 3.

To explain in more detail, in this embodiment, the first substrate 1 and the second substrate 4 are formed into rectangles, and the longitudinal lengths of the two are the same, while the lateral lengths are slightly longer than the first substrate 1. Therefore, a lateral end portion (the right end portion in the figure) of the first substrate 1 is exposed because the liquid crystal layer 3 and the second substrate 4 are not stacked. As described above, the first substrate 1 and the second substrate 4 are substrates having insulation and light transmission properties, and examples of the material for the formation thereof include glass and synthetic resin. The forming materials of the first substrate 1 and the second substrate 4 may be the same or different, but from the viewpoint of productivity and the like, the same materials are preferred. The thickness of the first substrate 1 and the second substrate 4 is usually set within a range of 15 to 250 μm. In this specification, the term "insulating property" refers to a property in which electricity or heat is difficult to flow, and the term "light-transmitting property" refers to a substrate through which electromagnetic waves such as light pass.

In this embodiment, the electrodes 2A and 2B are formed as a plurality of linear electrodes in a comb-shaped pattern, and the plurality of linear electrodes 2A and 2B are formed in a state branched from the rectangular electrode bases 21A and 21B. Next, an electrode body 20A composed of the electrode base 21A and the linear electrode 2A is formed, and an electrode body 20B composed of the electrode base 21B and the linear electrode 2B is formed so that they are in the following state: "in Between the adjacent linear electrodes 2A of the electrode body 20A on one side, the linear electrodes 2B of the electrode body 20B on the other side enter. In this state, the linear electrode 2A of the electrode body 20A on one side and the linear electrode 2B of the electrode body 20B on the other side are paired. In this embodiment, the pairings are plurally and uniformly formed on a portion corresponding to approximately the entire surface of the liquid crystal layer 3. Next, one end portions 22A and 22B of the electrode base portions 21A and 21B are exposed at the exposed portions of the first substrate 1 and become terminals for supplying voltage to the electrodes 2A and 2B from the outside.

The width of a linear electrode 2A, 2B is usually set to 15 μm or less. From the viewpoint of improving the reliability of voltage supply and forming the electrodes 2A, 2B at the same time, it is preferable to set it within a range of 5 to 10 μm. . The gap width between a pair of linear electrodes 2A and 2B is usually set in the range of 5 to 180 μm. From the viewpoint of improving the reliability of the generated electric field, it is preferably set to 15 to 130 μm. Within range.

Next, examples of the material for forming the electrode bodies 20A and 20B include metals such as silver, copper, and gold; conductive polymers such as PEDOT: PSS; and ITO (indium tin oxide). Among these, silver and copper are preferred from the viewpoint that the linear electrodes 2A and 2B can be formed more finely by printing. In addition, from the viewpoint of productivity, the two electrode bodies 20A and 20B are preferably both formed of the same forming material and formed at one time by printing or the like. However, the two electrode bodies 20A and 20B may be formed of different forming materials. The structures are each formed by printing or the like.

As described above, the liquid crystal layer 3 is a film-shaped one composed of a polymer and a liquid crystal composite material. In other words, the structure of the liquid crystal layer 3 is that the liquid crystal is limited to the voids of the skeleton after the polymer is combined into a sponge shape. Examples of the liquid crystal layer 3 having this structure include a polymer network liquid crystal (PNLC: Polymer Network Liquid Crystal), a polymer dispersed liquid crystal (PDLC: Polymer Dispersed Liquid Crystal), and the like. Examples of the polymer include a polyfunctional acrylate, a polyfunctional methacrylate, and a photopolymerizable monomer. Next, the thickness of the liquid crystal layer 3 is usually set in a range of 3 to 25 μm. From the viewpoint of making it easy to control the change of the orientation of the liquid crystal by an electric field, it is preferably set in a range of 3 to 15 μm.

In the light control film having such a configuration, a pair of linear electrodes 2A are formed by applying a voltage to one end portions 22A and 22B exposed from the electrode base portions 21A and 21B of the two electrode bodies 20A and 20B. An electric field is generated between, 2B to change the orientation of the liquid crystal in the liquid crystal layer 3. Thereby, the amount of light transmitted through the light control film is changed. That is, if the applied voltage is increased, the amount of light transmitted through the dimming film will also increase (the transmittance of light will increase).

Then, as described above, the light control film can be attached to a window glass, a sunroof, or the like of a house, a car, or the like, and the light transmission coefficient can be changed by application of a voltage to use. This attaching is attaching any one of the first substrate 1 and the second substrate 4 to a window glass or the like. Moreover, when no voltage is applied, since the light transmission coefficient is low, it can be used as a screen for projecting an image.

The said light control film can be manufactured as follows, for example. That is, first, the first substrate 1 is prepared, and the electrode bodies 20A and 20B composed of the electrode bases 21A and 21B and the linear electrodes 2A and 2B are formed on one side of the first substrate 1 by printing or the like. Next, the liquid crystal layer 3 and the second substrate 4 are prepared, and the electrode bodies 20A and 20B of the first substrate 1 face the second substrate 4, and the first substrate 1 and the second substrate 4 are sandwiched therebetween. Hold the above liquid crystal layer 3. In this way, the above-mentioned dimming film can be produced.

As described above, since the electrode body 20A composed of the electrode base 21A and the linear electrode 2A and the electrode body 20B composed of the electrode base 21B and the linear electrode 2B are formed only on the first substrate 1, short-circuit prevention performance can be improved. Furthermore, since the terminal forming process for supplying a voltage to the linear electrodes 2A, 2B requires only the end portions 22A, 22B of one of the electrode base portions 21A, 21B to be formed on the exposed portion of the first substrate 1, the terminal can be simplified. Form processing operations.

In addition, as the printing method of the electrode bodies 20A and 20B, any conventional printing method may be used, and examples thereof include ink jet printing, screen printing, gravure printing, gravure offset printing, flexographic printing, and backside offset printing. Printing method. Among these, from the viewpoint that the electrodes 2A and 2B can be formed more finely, gravure offset printing is preferred. Next, since the above-mentioned printing method uses a pre-made printing plate, it is easier to form the electrode bodies 20A and 20B. In this regard, the above-mentioned printing method is preferable. When the material for forming the electrode bodies 20A and 20B is ITO, the electrode bodies 20A and 20B are formed by etching or the like. In this manner, the electrode bodies 20A and 20B are formed by an appropriate method in accordance with the material for forming the electrode bodies 20A and 20B.

FIG. 2 is a cross-sectional view showing a second embodiment of the light control film of the present invention [corresponding to the cross-sectional view of FIG. 1 (b)]. The light control film of this embodiment is the light control film of the first embodiment shown in FIGS. 1 (a) and (b), and the second substrate 4 [see FIG. 1 (b)] is not provided. The other parts are the same as those in the first embodiment, and the same parts are assigned the same symbols.

This embodiment mode is also the same as the above-mentioned first embodiment mode, and the transmission coefficient of light can be changed by applying a voltage to obtain the same function and effect as those of the first embodiment mode. In this embodiment, attaching to a window glass or the like means attaching any of the first substrate 1 and the liquid crystal layer 3 to the window glass or the like.

In each of the above embodiments, the electrodes 2A and 2B of the electrode bodies 20A and 20B are made linear. However, as long as an electric field can be generated between the pair of electrodes 2A and 2B, it may be The other shapes may be, for example, a zigzag shape, a wave shape, a swirl shape, or the like. In addition, two or more types of these shapes may be combined.

In each of the above embodiments, the plurality of counter electrodes 2A and 2B are uniformly formed on a portion corresponding to approximately the entire surface of the liquid crystal layer 3, but they may be formed unevenly. That is, a region where a plurality of counter electrodes 2A, 2B are formed and a region where a plurality of counter electrodes 2A, 2B are not formed may be set. Furthermore, the gap width between the pair of electrodes 2A and 2B may be changed. For example, a region with a smaller gap width and a larger region may be set. In this way, regions with different light transmission coefficients can be formed in a single light-adjusting film, and a light-adjusting film with rich design can be formed.

Next, in each of the above embodiments, the pairs of the electrodes 2A and 2B are formed into a plurality of pairs, but only one pair may be formed.

Next, examples will be described. However, the present invention is not limited to the examples.
[Example]

[Examples 1 to 4]
[First substrate on which electrodes are formed]
A first substrate (thickness: 250 μm) made of PET (polyethylene terephthalate) similar to the first embodiment shown in FIGS. 1 (a) and (b) was prepared, and was printed on the substrate by gravure offset printing. An electrode body made of silver composed of an electrode base and a linear electrode is formed on one surface of the first substrate. At this time, four examples (Examples 1 to 4) with different electrode widths and gap widths between the paired electrodes were prepared. These electrode widths and gap widths are shown in Table 1 below.

[Transmission coefficient of light of the first substrate on which the electrodes are formed]
In the state where no voltage was applied, the transmission coefficient of parallel light was measured on the first substrate on which the electrodes were formed, and the results are shown in Table 1 below. This measurement was performed using a visible light transmission coefficient measuring device (manufactured by Sato Corporation, glass visible light transmission coefficient measuring device colorimeter MJ-TM100).

[Liquid crystal layer]
As the liquid crystal layer, KN-221W (thickness: 10 μm, polymer: polyfunctional acrylate) manufactured by Kyushu Nanotech Optics Co., Ltd. was prepared.

[Second substrate]
As the second substrate, a substrate (thickness: 50 μm) made of PET was prepared.

[Production of dimming film]
The electrode body of the first substrate faces the second substrate, and the liquid crystal layer is sandwiched between the first substrate and the second substrate. Thereby, the dimming films of Examples 1 to 4 were produced in the same manner as the first embodiment shown in FIGS. 1 (a) and 1 (b).

When the light-adjusting film is manufactured, short-circuiting of the electrode body does not occur, so special attention is not required to prevent the short-circuiting. In addition, since the terminal forming process for supplying a voltage to a linear electrode requires only one end portion of the electrode base portion to be formed on the exposed portion of the first substrate, the terminal forming process operation is relatively simple.

[Light transmission coefficient of light control film]
In the dimming films of Examples 1 to 4, the applied voltage was changed to measure the transmission coefficient of parallel light. This measurement uses the same visible light transmittance measuring device as described above. The results are shown in Table 1 below.

【Table 1】

It is known from the results in Table 1 that the greater the voltage applied to the light control films of Examples 1 to 4, the higher the light transmission coefficient. That is, the dimming films of the above embodiments 1 to 4 can change the amount of transmitted light by changing the applied voltage.

In addition, in the above-mentioned Examples 1 to 4, a light-adjusting film without a second substrate was also prepared (see FIG. 2). These light control films also obtained results showing the same tendency as those of the above-mentioned Examples 1 to 4.

Although the above-mentioned embodiment shows a specific form of the present invention, the above-mentioned embodiment is merely a mere illustration and is not to be construed as a limitation. Various modifications obvious to those skilled in the art in this technical field are intended to be included in the scope of the present invention.
[Industrial availability]

The light-adjusting film of the present invention can be used in a case where it is attached to a window glass, a sunroof, etc. of a house or a car, and the light transmission coefficient is changed.

1‧‧‧ the first substrate

2A, 2B‧‧‧electrode

3‧‧‧LCD layer

4‧‧‧ second substrate

20A, 20B‧‧‧ electrode body

21A, 21B‧‧‧ electrode base

22A, 22B‧‧‧End

X-X‧‧‧ section line

Fig. 1 is a schematic view showing a first embodiment of the light control film of the present invention, (a) is a plan view thereof, and (b) is a sectional view taken along line X-X of (a).

FIG. 2 is a cross-sectional view schematically showing a second embodiment of the light control film of the present invention.

Claims (3)

A dimming film, comprising: The first substrate has insulation and light transmission properties; One or more pairs of linear electrodes formed on one side of the first substrate; and The liquid crystal layer is composed of a polymer and a liquid crystal composite material, and is laminated on the electrode forming surface of the first substrate. The dimming film as described in claim 1, wherein: A second substrate having an insulating property and a light-transmitting property is laminated on a surface of the liquid crystal layer opposite to the first substrate. The dimming film according to claim 1 or 2, wherein: These electrodes are formed by printing.