JP7222177B2 - Light control film, light control device and light control apparatus - Google Patents

Description

TECHNICAL FIELD The present invention relates to a light control film having a colored layer, and a light control device and a light control apparatus using the light control film.

Light control film and light control glass consist of two transparent substrates such as a transparent resin film or a transparent glass substrate having a transparent conductive film, with the transparent conductive film side facing inward, and a layer with a light control function such as a liquid crystal (light control film). layer) is sandwiched.
For example, when a polymer-dispersed liquid crystal material is used for the light control layer, the degree of light scattering can be changed by applying an AC voltage to the light control layer of such a laminate via a transparent conductive film. You can control the transparent and opaque states. Therefore, the transmittance of light can be changed.
In addition, light transmittance can be adjusted by using a light control film having a light control layer in which the liquid crystal material used in the liquid crystal display is oriented and linearly polarizing plates are arranged on both sides of the light control film. It can be a light control film that can be used.

Proposals have been made to use light control laminated glass, which is produced by sandwiching a light control film capable of adjusting light transmittance between two glass plates, for electronic blinds and the like (for example, Patent Document 1).

Such a light control laminated glass is suitably used for vehicle window glass, for example. BACKGROUND ART Conventionally, it is desired that a window glass for a vehicle is configured to exhibit a predetermined color from the viewpoint of designability and light-shielding properties. As a matter of course, the same coloring specifications are also required for the light control laminated glass.

As a technique for meeting such demands, Patent Document 1 proposes a light control laminated glass using a light control film using a guest-host type liquid crystal containing a dichroic dye.

Dichroic dyes have excellent design properties, but have problems of limited usable colors and poor weather resistance. Therefore, it is considered that it is not suitable for applications such as electronic blinds that are exposed to sunlight for a long period of time. In addition, there has been a long-awaited demand for light-control laminated glass with a variety of colors and a high degree of design.

JP 2017-187810 A

In view of the above circumstances, an object of the present invention is to provide a light control film that has excellent weather resistance and a high designability by having a desired color when transparent, and a light control device using the same. .

As a means for solving the above problems, the light control film according to the present invention is obtained by laminating a light control layer with the transparent conductive film sides of two transparent resin films having transparent conductive films facing each other. in the film
The light control layer is a layer made of a liquid crystal material that can change the degree of light scattering by applying a voltage,
At least one transparent colored layer is provided outside or inside the transparent resin film,
The transparent colored layer is a light control film characterized by being colored with a pigment.

Since the degree of light scattering can be changed by the AC voltage applied to the dimming layer, the transparent state and the opaque state can be switched, so that a low haze state can be achieved. In addition, since at least one layer of transparent colored layer is provided, it is possible to make the transparent colored layer have a desired color, and since the color is created by pigments, it has excellent weather resistance. there is Moreover, since an expensive colorant such as a dichroic dye is not used, it can be manufactured at a low cost.

A second embodiment of the light control film is characterized in that the total light transmittance T1 in the opaque state is 8% ≤ T1 ≤ 60% and the total light transmittance T2 in the transparent state is 13% ≤ T2 ≤ 75%. and

By setting the total light transmittance in the opaque state and the transparent state in this manner, it is possible to achieve both privacy in the opaque state and visibility in the transparent state.

A third aspect of the light control film is that the transmission hues a ^* and b ^* defined by the CIE1976L ^* a ^* b ^* display system are |a ^* |≤10 and |b ^* |≤15. Characterized by

By setting the hue in this way, it is possible to realize a neutral black color.

In the fourth aspect of the light control film, the color difference ΔE ^* ab in the CIE1976L ^* a ^* b ^* display system after the weather resistance test is 10 or less compared to before the weather resistance test.

By setting the color difference ΔE ^* ab before and after the weather resistance test in this manner, a highly reliable light control film can be provided.

A fifth aspect of the light control film is characterized in that any one of the transparent colored layers is adhesive.

By imparting adhesiveness to any one of the transparent colored layers, the layer can be integrated with the adhesive layer to reduce the film thickness and facilitate post-application workability.

A sixth aspect of the light control film is characterized in that any one of the transparent colored layers has transparent conductivity.

By imparting transparent conductivity to any one of the transparent colored layers, the film thickness can be reduced by integrating with the electrode layer, and bonding to a curved surface can be facilitated.

In a seventh aspect of the light control film, any one of the transparent colored layers is made of one of colored polyethylene terephthalate, cycloolefin polymer, oriented polypropylene, nylon, polycarbonate, and polyimide, or a combination thereof. It consists of a transparent film substrate made of a material such as

By using the above material for any one of the transparent colored layers, it is possible to provide a light control film with high clarity and low haze.

In an eighth aspect of the light control film, any one of the transparent colored layers contains either one or both of polyvinyl butyral and ethylene/vinyl acetate copolymer resin.

The light control film can be made into a laminated glass by using the material described above for any one of the transparent colored layers.

A ninth aspect of the light control film is characterized in that any one of the transparent colored layers is a glass plate or a resin plate.

By using the material described above for any one of the transparent colored layers, it is possible to provide a highly durable light control device.

A tenth aspect of the light control film is the light control film according to any one of claims 1 to 9, wherein a UV cut layer, a transparent colored layer, and are provided in this order.

By always providing the UV cut layer on the side of the transparent colored layer on which light from the light control film is incident, deterioration of the transparent colored layer by light can be suppressed, and weather resistance can be improved.

In an eleventh aspect of the light control film, the UV cut layer has a maximum transmittance of 1% or less in a wavelength range of 300 nm to 380 nm, and has a yellow color according to the calculation method specified in JIS K 7373:2006. degree YI is 0≤YI≤10.

By setting the maximum transmittance of the UV cut layer to 1% or less in the wavelength region of 300 nm to 380 nm, it is possible to effectively improve the weather resistance, and the yellowness index YI is reliably 0 ≤ YI ≤ 10. becomes possible.

In a twelfth aspect of the light control film, the UV cut layer is made of an adhesive material containing an acrylic resin.

By using an adhesive containing an acrylic resin for the UV cut layer, yellowing due to light can be prevented.

In a thirteenth aspect of the light control film, the UV cut layer contains either one or both of polyvinyl butyral and ethylene/vinyl acetate copolymer resin.

By using the above material for the UV cut layer, the light control film can be used as a laminated glass.

A fourteenth aspect of the light control film comprises an alignment layer of the liquid crystal material between the light control layer and the transparent conductive film.

By forming an orientation layer of a liquid crystal material between the light control layer and the transparent conductive film, the liquid crystal is oriented in a non-energized state and the reverse mode of the transparent light control film can be realized.

Further, the light control device according to the present invention is characterized by bonding a transparent substrate or a colored transparent substrate to one or both sides of the light control film having each of the above aspects via an adhesive layer or an adhesive layer. and

Further, a light control device according to the present invention comprises the light control device, an AC power source for driving the light control device, and a control device for controlling the AC power applied to the light control device. Characterized by

Since the light control film of the present invention includes a transparent colored layer, a colorable transparent resin film, an adhesive layer, and the like, the color of the light control film can be selected from a wide range. Therefore, designability can be dramatically improved. In addition, since it is colored with a pigment, it has high weather resistance, and since it does not use an expensive dichroic dye, it can be manufactured at a low cost.

BRIEF DESCRIPTION OF THE DRAWINGS Sectional explanatory drawing which illustrated the layer structure of the light control film of this invention. BRIEF DESCRIPTION OF THE DRAWINGS Cross-sectional explanatory drawing which illustrated the layer structure of the light control laminated glass of this invention. Explanatory drawing which illustrates the structure of the light control apparatus of this invention.

The light control film of the present invention and the light control device and light control apparatus using the light control film will be described with reference to FIGS. 1 to 3. FIG.

<Light control film>
A light control film 100 of the present invention will be described with reference to FIG.
The light control film 100 of the present invention is formed by laminating two sheets of transparent resin films 31 and 32 having transparent conductive films 41 and 42 with the transparent conductive film sides facing each other and sandwiching the light control layer 10 therebetween. It's a film.

In the light control film 100 of the present invention, the light control layer 10 is a layer made of a liquid crystal material that can change the degree of light scattering by applying voltage. Also, FIG. 1 shows an example in which one transparent colored layer 22 is provided inside the transparent resin film 32 and the adhesive layer 21 is provided outside the transparent resin film 31 . The transparent colored layer 22 may be provided inside or outside the transparent resin films 31 and 32, and a plurality of transparent colored layers 22 may be provided.

Moreover, the transparent colored layer 22 is colored with a pigment. By being colored with a pigment, it is possible to obtain a wide range of selection, obtain a desired tint, and at the same time obtain excellent weather resistance.

(transparent resin film)
The transparent resin films 31 and 32 are not particularly limited as long as they are films made of transparent resin. For example, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PE (polyethylene), PP (polypropylene), PC (polycarbonate), PPS (polyphenylene sulfide), PEEK (polyether ketone), PES (polyether sulfone), etc. A film consisting of can be preferably used.

(transparent conductive film)
The transparent conductive films 41 and 42 are thin films of ITO (Indium Tin Oxide), ZOA (zinc oxide to which aluminum is added), tin oxide, etc. formed on the surfaces of the transparent resin films 31 and 32 . Examples of thin film forming methods include a sputtering method using a direct current magnetron sputtering apparatus, a vacuum vapor deposition method using a vacuum vapor deposition apparatus, and a thin film forming method using an ion plating apparatus.

When ITO is used as the transparent conductive films 41 and 42 and patterning is performed using photolithography, first, an amorphous ITO thin film is formed on the surfaces of the transparent resin films 31 and 32, patterned, and then oxidized at around 190°C. It is crystallized by performing heat treatment in an atmosphere. This treatment can increase electrical conductivity and light transmittance.

(Light control layer)
Polymer-dispersed liquid crystal or other liquid crystal materials can be used as the light control layer 10 . As the light control layer 10, there are a normal type and a reverse type, either of which may be used. In the normal type, for example, a polymer-dispersed liquid crystal is used for the light control layer, and when an appropriate AC voltage is applied to the light control layer, the degree of light scattering (haze) becomes small, the state becomes transparent, and no voltage is applied. , the haze increases and becomes opaque. The reverse type is the opposite, consumes less power than the normal type, and becomes transparent when no voltage is applied due to a power failure, etc., so it is possible to check the inside, which is an advantage depending on the application.

As a method for forming the light modulating layer 10, various coating techniques can be used. For example, a coating method using a screen printer, a roll coater, a die coater, a gravure printer, a microgravure printer, or the like can be mentioned.

(transparent colored layer)
At least one layer of the transparent colored layer 22 may be formed outside the transparent resin films 31 and 32 (the side opposite to the light control layer 10 side), or may be formed inside (the light control layer 10 side). It's okay to be there. When formed inside, it may be formed between the transparent conductive films 41 and 42 and the transparent resin films 31 and 32 or may be formed on the surfaces of the transparent conductive films 41 and 42 .

Also, one of the transparent colored layers 22 may have adhesiveness.

Further, one of the transparent colored layers 22 may have transparent conductivity.

Also, the transparent colored layer 22 is a transparent film substrate made of any one of colored polyethylene terephthalate, cycloolefin polymer, oriented polypropylene, nylon, polycarbonate, polyimide, or a combination thereof. can be

Also, the transparent colored layer 22 may be a colored glass plate or a colored resin plate.

Moreover, it is preferable that the transparent colored layer 22 is provided with a UV cut layer and the transparent colored layer 22 in this order from the light-incident side of the light control film 100 . With such a configuration, the light incident on the light control film 100 always passes through the UV cut layer and reaches the transparent colored layer 22, so that the ultraviolet rays that cause deterioration of the transparent colored layer 22 can be blocked. . Therefore, the weather resistance is remarkably improved.
The UV cut layer preferably has a maximum transmittance of 1% or less in a wavelength range of 300 nm to 380 nm, and a yellowness index YI of 0 ≤ YI ≤ 10 according to the calculation method specified in JIS K 7373:2006. . By doing so, it is possible to minimize deterioration of color due to ultraviolet rays.

The UV cut layer may be an adhesive material containing an acrylic resin, or a material containing either one or both of polyvinyl butyral and ethylene/vinyl acetate copolymer resin. can be

As for the colored layers, not only the transparent colored layer 22 but also the transparent resin films 31 and 32 may be colored. Also, the transparent conductive films 41 and 42 may be similarly colored.

Further, an alignment layer for controlling the alignment of the liquid crystal material contained in the light control layer 10 may be provided between the light control layer 10 and the transparent conductive films 41 and 42 .

(Total light transmittance)
The light control film 100 of the present invention has a lower total light transmittance in the opaque state than in the transparent state. This is because the degree of light scattering in the opaque state is greater than the degree of light scattering in the transparent state, so the amount of transmitted light in the opaque state is reduced. Further, it is desirable that the total light transmittance T1 in the opaque state satisfies 8%≦T1≦60% and the total light transmittance T2 in the transparent state satisfies 13%≦T2≦75%.

If the total light transmittance T1 in the opaque state is less than 8%, the visibility in the transparent state is deteriorated.

(hue)
Transmission hues a* ^and b* defined by the CIE1976L ^* a ^* b ^* display system of the ^light control film 100 of the present invention are preferably |a ^* |≤10 and |b ^* |≤15.

If |a ^* | exceeds 10, red or green becomes stronger, which is not preferable. On the other hand, if |b ^* | exceeds 15, the red or green color becomes stronger, which is not preferable.

(Color difference)
The color difference ΔE ^* ab in the CIE1976L ^* a ^* b ^* display system before and after the weather resistance test of the light control film 100 of the present invention is desirably 10 or less.

When the color difference ΔE ^* ab exceeds 10, deterioration due to light occurs, which is not preferable.

<Dimmer device>
Next, the light modulating device of the present invention will be described with reference to FIG.
The light control device 200 of the present invention can be produced by bonding the transparent substrates 61 and 62 to the light control device 100 of the present invention via the adhesive layers 51 and 52 .
Although FIG. 2 illustrates the case where the transparent substrates 61 and 62 are attached to both sides of the light modulating device 100, it may be attached to only one side. Here, the adhesive layers 51 and 52 may contain either one or both of the adhesive composition and the pressure-sensitive adhesive composition.

<Dimmer>
Next, the light control device of the present invention will be explained with reference to FIG.
A dimming device 300 of the present invention includes a dimming device 200 and a control device 70 that controls an AC voltage that drives the dimming device 200 . The dimming device 200 is connected to the control device 70 by wiring 90 . The controller 70 is connected to the AC power supply 80 by wiring 91 .

The AC power supply 80 is a commercial power supply that can normally be taken from an outlet. For example, by inserting a plug into a wall outlet, it can be connected to a commercial power supply of 100 V, 50 Hz. By connecting the commercial power supply to the control device 70, the control device 70 generates an AC voltage that brings the light control device 200 into a transparent state (when a normal mode light control film is used). Applying the generated AC voltage to the dimming device 200 results in a transparent state, and cutting off the AC voltage results in an opaque state. The controller 70 also serves as a switch that switches between application (ON) and disconnection (OFF) of the AC voltage.

Next, examples of the present invention will be described.
In Examples 1 to 7 and Comparative Examples 1 to 3, using the light control film having the layer structure shown in FIG. 1, samples with different colored layers were prepared, and their optical properties before the weather resistance test (Also referred to as initial optical characteristics.) and optical characteristics after the weather resistance test, the total light transmittance in the opaque state (T1), the total light transmittance in the transparent state (T2), and the CIE1976L ^* a ^* b ^* in the display system It was evaluated by measuring the color difference ΔE ^* ab. A normal mode liquid crystal material was used for the light control layer.

A weather resistance test was performed using an Eye Super UV Tester SUV-W261 (manufactured by Iwasaki Electric Co., Ltd.) at a temperature of 63° C., a humidity of 60% RH, an illumination of 650 W/m ² , and no shower for 100 hours. The color difference ΔE ^* ab was measured using a spectrophotometer U4100 (manufactured by Hitachi High-Tech Science).

A case where T1 satisfies 8%≦T1≦60% was evaluated as good (◯), and other cases were evaluated as poor (x).
In addition, when T2 was 13%≦T2≦75%, it was evaluated as good (◯), and otherwise, it was evaluated as bad (x).

In addition, when the color difference ΔE ^* ab in the CIE1976L ^* a ^* b ^* display system after the weather resistance test was 10 or less, it was evaluated as good (◯), and the other cases were evaluated as bad (×).
The total light transmittance was measured according to the method specified in JIS K 7361 using a haze meter NDH7000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

<Example 1>
First, a light control film was produced. Two PET films having a thickness of 50 μm were prepared as transparent resin films.

Next, on one side of one of the PET films, a color resist coating solution obtained by removing the photosensitive component from the photosensitive color resist used in the manufacture of the liquid crystal color filter is applied so that the thickness after drying becomes 1 μm, and dried. By doing so, a transparent colored layer 22 was formed.

The color resist coating liquid was prepared as follows.
First, an epoxy acrylate resin (V-259-SF manufactured by Nippon Steel Chemical Co., Ltd.: trade name) was diluted with ethyl cellosolve acetate to a resin concentration of 10%. 27.0 g of a red pigment and 0.9 g of a dispersing agent were added to 91.0 g of this diluted resin, and the mixture was thoroughly kneaded with a triple roll to prepare a red colored resin. As a red pigment, C.I. I. No. 9 was used. A wide variety of dispersants are used, including surfactants, intermediates for pigments, intermediates for dyes, Solsperse, and the like. The proportion of the composition during dispersion is not particularly limited, but the amount of the pigment added to the acrylic resin for dispersion is about 50 to 150 parts by weight, and the dispersant is about 1 to 10 parts by weight of the pigment.

Next, on the transparent colored layer 22, an indium target is sputtered in an oxidizing atmosphere using a single-wafer DC magnetron sputtering apparatus so as to have a thickness of 100 nm.
A TO thin film was formed and used as a transparent conductive film 42 . When the colored transparent conductive films 41 and 42 were formed, the colored ITO thin films were formed using an ITO target containing a red pigment and a high-frequency magnetron sputtering apparatus.

Next, an ITO thin film was formed on one side of the other PET film to a thickness of 100 nm using a single-wafer DC magnetron sputtering apparatus to form a transparent conductive film 41 . Next, a coating liquid composed of an adhesive composition was applied to the other surface using a roll coater to form an adhesive layer 21 . The thickness was about 5 μm.

Next, a coating liquid is prepared by uniformly dispersing resin beads having an average particle diameter of 5 μm in a mixed liquid of a nematic liquid crystal material and an ultraviolet curable resin, and a transparent colored layer of a PET film having a transparent colored layer 22 formed thereon is prepared. 22 was coated using a roll coater to obtain a coating film to be the light control layer 10 .

Next, the light control film 100 was obtained by laminating the transparent conductive film side of the other PET film on which the adhesive layer 21 was formed so as to face the coating film.

Using the light control film 100 produced in this way, the total light transmittance T1 when the light control layer 10 is in an opaque state by applying a voltage, and the total light transmittance T1 when it is in a transparent state without applying a voltage. A light transmittance T2 was measured. Next, the color difference ΔE ^* ab after the weather resistance test was measured.

<Example 2>
The composition of the color resist coating solution was the same as in Example 1, except that the red pigment was changed to a red dye, Acid Red 87.

<Example 3>
The composition of the color resist coating liquid was the same as in Example 1 except that the amount of red pigment was changed to 9.0 g.

<Example 4>
The composition of the color resist coating liquid was the same as in Example 3, except that 4.5 g of the red pigment was used.

<Example 5>
It was the same as Example 3 except that the transparent colored layer was colorless, the colored layer was a transparent resin film, and the transparent conductive film was used as the colored layer.

<Example 6>
The same procedure as in Example 3 was performed except that the transparent colored layer was colorless and the colored layer was a transparent resin film.

<Example 7>
The same procedure as in Example 3 was performed except that the transparent colored layer was colorless and the colored layer was used as the adhesive layer.

<Comparative Example 1>
The procedure was the same as in Example 1, except that the transparent colored layer was colorless and the dimming layer was colored with a dichroic dye.

<Comparative Example 2>
The composition of the color resist coating solution was the same as in Example 1, except that 36.0 g of the red pigment was used.

<Comparative Example 3>
The composition of the color resist coating liquid was the same as in Example 1 except that the red pigment was changed to 4.5 g.

Regarding the light control films produced in Examples 1 to 7 and Comparative Examples 1 to 3 above, the total light transmittance in the opaque state without voltage applied and the transparent state with an AC voltage of 40 V applied was measured before the weather resistance test. were measured respectively. Also, the color difference ΔE ^* ab after the weather resistance test was measured. Table 1 summarizes the above measurement results and evaluation results.

As shown in Table 1, in Examples 1 to 7, before the weather resistance test (initial optical properties), the total light transmittance T1 in the opaque state and the total light transmittance T2 in the transparent state were both 8%. ≦T1≦60% and 13%≦T2≦75%, and the evaluation results were all good (○). On the other hand, in Comparative Example 1, T1 and T2 were good (○), but the color difference ΔE ^* ab after the weather resistance test exceeded 10 and was poor (×). In Comparative Examples 2 and 3, the color difference ΔE ^* ab after the weather resistance test was 10 or less and was good (○), but T1 and T2 were all 8%≦T1≦60% and 13%≦T2≦75%. It was not in the range of , and was defective (x).

The above is the embodiment of the present invention. The present invention is not limited to the above configuration, and can be modified without departing from the gist of the present invention. For example, in the above embodiment, the pigment is selected as the colorant with emphasis on weather resistance. Colorants other than pigments can be used in the light control film or the like according to the present invention, depending on user needs and what kind of design feeling is to be provided. For example, metal particles can be mixed in instead of pigments.

10... Light control layer 21... Adhesive layer 22... Transparent colored layers 31, 32... Transparent resin films 41, 42... Transparent conductive films 51, 52... Adhesive layers 61, 62... Transparent glass substrate 70 Control device 80 AC power supply 90, 91 Wiring 100 Light control film 200 Light control device 300 Light control device

Claims (11)

A light control film obtained by laminating a light control layer with the transparent conductive film sides of two transparent resin films having transparent conductive films facing each other,
The light control layer is a layer made of a liquid crystal material that can change the degree of light scattering by applying a voltage, and at least one transparent colored layer is provided outside or inside the transparent resin film, and the transparent colored layer is provided on the outside or inside of the transparent resin film. The layer is characterized in that it is colored with a pigment,
The total light transmittance T1 in the opaque state is 8% ≤ T1 ≤ 60%, and the total light transmittance T2 in the transparent state is 13% ≤ T2 ≤ 75%,
The light control film , wherein any one layer of the transparent colored layers has adhesiveness or transparent conductivity . Any one of the transparent colored layers is made of a transparent film substrate made of one of colored polyethylene terephthalate, cycloolefin polymer, oriented polypropylene, nylon, polycarbonate, polyimide, or a combination thereof. The light management film according to claim 1, characterized in that. 3. The light control film according to claim 1, wherein one of the transparent colored layers contains one or both of polyvinyl butyral and ethylene/vinyl acetate copolymer resin. . 3. The light control film according to claim 1, wherein one of the transparent colored layers is a colored glass plate or a colored resin plate. 5. The light control film according to any one of claims 1 to 4, characterized in that a UV cut layer and a transparent colored layer are provided in this order from the side of the light control film on which light is incident. dimming film. The UV cut layer has a maximum transmittance of 1% or less in a wavelength range of 300 nm to 380 nm, and a yellowness index YI according to the calculation method specified in JIS K 7373: 2006 is 0 ≤ YI ≤ 10. The light control film according to claim 5. 7. The light control film according to claim 5, wherein the UV cut layer is made of an adhesive containing an acrylic resin. 8. The light control film according to any one of claims 5 to 7, wherein the UV cut layer contains one or both of polyvinyl butyral and ethylene/vinyl acetate copolymer resin. 9. The light control film according to claim 1, further comprising an alignment layer of the liquid crystal material between the light control layer and the transparent conductive film. A light control device comprising a transparent substrate or a colored transparent substrate laminated on one or both sides of the light control film according to any one of claims 1 to 9 via an adhesive layer or an adhesive layer. A light control device comprising: the light control device according to claim 10; and a control device for controlling an AC voltage for driving the light control device.

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