JP2547416B2 - Method of manufacturing light control plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a method for manufacturing a light control plate, in particular, it selectively scatters only incident light from a predetermined angle range, and does not scatter incident light at other angles. The present invention relates to a method of manufacturing an ultraviolet-curable angle-dependent light control plate that transmits light.

<Prior Art> Conventionally, as an angle-dependent light control plate (see JP-A-57-18).
9439) such as a micro louver with a structure in which a transparent plate and an opaque plate are laminated, or a device that controls the visual field by drawing a thick grid pattern to make it opaque. It is used. However, these microlouvers have low transparency when transmitting light, and interference fringes may appear depending on the angle of use. Further, these conventional alignment films and light-shielding plates have problems that they are expensive because the manufacturing method is complicated and the film quality is not uniform.

Recently, a light control plate by UV curing has been developed that does not have these problems as seen in (Japanese Patent Application No. 61-302500). That is, a resin composition composed of an oligomer or a monomer having a difference in refractive index of photopolymerization or a mixture thereof is maintained in a film shape, and by irradiating it with ultraviolet rays from a specific direction to cure the resin composition, light in a predetermined range is obtained. A light control plate having a function of only scattering is obtained.

The resulting film-shaped cured product exhibits anisotropy with respect to the major axis and minor axis directions of the ultraviolet light source, and scatters light in a predetermined angle range only when rotated about the major axis direction of the light source. That is, the film-shaped cured product produced has regions with different refractive indices, oriented in a certain direction, and light incident from a predetermined angle range is totally reflected at the boundary of regions with different refractive indices and scattered. It is supposed to do.

<Problems to be Solved by the Invention> However, even with the above-mentioned ultraviolet curing type light control plate, like the microlouver, the entire surface of one substrate can only perform light control in a single direction. To solve this problem, as shown in Japanese Patent Application No. 61-302500, it is possible to use a photomask to provide various areas with different light control directions and light control angles on a single substrate. However, this mask pattern could not be duplicated.

<Means for Solving the Problem> The present invention is to solve the above-mentioned conventional problems, and the present invention is a resin containing at least two photopolymerizable oligomers or monomers having a difference in refractive index. In the method for producing a light control plate having a function of scattering the incident light in a predetermined angle range by maintaining the composition in a film shape and irradiating the annular body with light from a specific direction to cure the composition, A photomask having a first shape is arranged between the linear light irradiation source and the film-shaped body to irradiate light from the irradiation source, and at the same time, the first light irradiation source is applied to the film-shaped body. A second linear light irradiation source is arranged on the opposite side, and a photomask having a second shape is arranged between the second irradiation source and the film-shaped body to irradiate light from the second irradiation source. A method of manufacturing a light control plate, comprising: Further, it is possible to duplicately manufacture portions having different light control directions and angles.

In the manufacture of the light control plate of the present invention, the light control function is formed during the curing of the resin. Therefore, in order to have different light control functions on both sides, it is desirable to apply different photomasks to the both sides and simultaneously irradiate light for photopolymerization, for example, ultraviolet rays. If you irradiate only one side first,
The curing proceeds to the opposite surface, and different light control functions cannot be formed from the opposite surface, so that the object of the present invention is not achieved.

The linear irradiation light source used in the present invention emits ultraviolet rays or other light that contributes to photopolymerization, and the light source has a linear shape when viewed from the irradiation position (film surface). is there. The size of the light source viewed from the irradiated position is such that the viewing angle A in the long axis direction of the light source is at least 8 °, preferably at least 12 °, and the viewing angle B in the short axis direction of the light source is at most A /
4, more preferably at most A / 10. A rod-shaped UV lamp is one of the preferred linear irradiation light sources. When a rod-shaped UV lamp (3 KW) with a length of about 40 cm and a thickness of about 2 cm is placed 40 cm above a horizontally-held 10 cm x 10 cm film so that the lamp is parallel to the film surface, the viewing angle A is about It is 54 ° and the viewing angle B is about 3 °, which is a preferred linear light source in the present invention. In addition to such a linear light source, the light source is apparently linear when viewed from the irradiation position, for example, a large number of point light sources arranged in a line, or a laser beam. An apparatus configured to scan (irradiate from a plurality of different angles with respect to one point of an irradiation position) the light from the above using a rotating mirror and a concave mirror can also be used as the linear light source.

Above the unpolymerized film placed horizontally, for example, at about 40 cm above the linear irradiation light source at a position inclined by about 45 ° measured from a vertical plane standing from the center of the film surface, the length direction of the light source is When the film is irradiated with light so as to be parallel to the vertical plane and horizontally to cause a curing reaction of the film, anisotropy is generated in the formed film. That is, when the cross section of the film is viewed as shown in FIG. 9, a layer 13 having a microstructure is formed inside the film 11 near the irradiated side surface 12. The thickness d2 of this layer is about 10-2000 microns and the depth d1 of the layer from the surface is 0-500 microns. The film thickness d3 here is usually 10-5000 microns. As shown in FIG. 10 which is a plan view and FIG. 11 which is a side view, the microstructure layer 13 is composed of a large number of elongated micropieces 14 extending in a direction parallel to the linear irradiation source 15. As shown in FIG. 12 which is a sectional view taken along the line AA in FIG. 10, each of the minute pieces 14 is inclined by an angle Z ′ smaller than the irradiation direction Z of light from the irradiation source. To be observed. This angle Z'is substantially equal to the refraction angle at which the irradiated light refracts and travels in the film. The pitch d5 of each micro-piece 14 is 0.01-50 microns. The light selective scattering property of this film is shown in FIG.
Light incident at an angle Y1 equal to the irradiation angle Z from the irradiation source and light incident at an angle Y2 equal to the irradiation angle Z on the opposite side of the film are scattered most strongly. In other words, when you look at the other side through the membrane at that angle, it becomes most cloudy and obstructs your view.
The incident light is not limited to the incident light parallel to the paper surface of FIG. 13, but the light incident on the film through the plane including the light ray having the incident angle Y1 or Y2 and perpendicular to the paper surface (projected on the paper surface. Incident light whose incident angle is equal to Y1 or Y2) is also scattered most strongly. As shown in FIG. 14, the haze ratios for light with various incident angles show a mountain-shaped glacular shape which is the maximum in the vicinity of the incident angle of Z. It has been found that the thickness of the film is relatively large, and when light from a linear light source is applied from both sides of the film, microstructure layers are formed inside the front and back surfaces of the film, respectively.

If the size of the irradiation light source becomes smaller and the viewing angle A in the major axis direction becomes less than 5 ° in terms of the viewing angle, the polymerized film no longer exhibits anisotropy and the direction of incidence It also scatters light. As described above, the film polymerized by using the point light source as the irradiation light source or the substantially parallel light exhibits non-directional light scattering.

On the contrary, when the size of the irradiation light source is gradually increased, the height of the peak in the haze ratio graph is decreased, and the size of the irradiation light source is expressed by the above-mentioned viewing angle, and the viewing angle B in the minor axis direction is larger than 100 °. When it becomes, it no longer exhibits anisotropy.
That is, the irradiated and polymerized film is transparent from any direction and does not exhibit selective light scattering. Examples of such a light source include a surface light source arranged relatively close to the film to be polymerized, or a diffuse light source. Also, when the film is polymerized by heating, it becomes transparent.

The reason why the film polymerized by using the linear irradiation source exhibits the selective light scattering property is not clear, but it can be estimated as follows. In Figure 12, the particles 14 and the material 16 between them probably have different refractive indices (this different refractive index is the refractive index of the photopolymerizable oligomer or monomer used as the raw material of the film). It is considered that there is a deep relationship with the difference), and the light entering the film at an angle close to the inclination angle Z ′ of the micropiece has an angle larger than the critical reflection angle determined by the refractive indexes of the micropiece 14 and the substance 16. As a result of colliding with the surface of the minute piece and repeating reflection on the surface of the minute piece, the light passing through the film becomes scattered light. When the refraction angle of the light entering the film deviates more than the tilt angle Z ′, it becomes smaller than the reflection critical angle and the reflection decreases, so that the light passing through the film goes straight without being scattered. Become light. Strictly speaking, a dent (a slight decrease in the haze ratio) is observed at the top of the graph shape of the haze ratio as shown in FIG. It is considered that this is because the light having the traveling direction in which the minute pieces 14 in the film are inclined and exactly coincides with each other goes straight through the gap between the minute pieces without being reflected at the boundaries of the minute pieces.

When the irradiation light source is a surface light source or a diffused light source, such a microstructure is not formed, and the film is transparent and does not show selective light scattering. Also, when the irradiation light source is a point light source, although microstructures are formed in the film, they are randomly arranged without regularity as in the case of a linear irradiation source, and therefore any incident light It is thought that it may be a film that reflects in the microstructure and gives non-directional light scattering.

The photopolymerizable oligomers and monomers used in the present invention are those which are polymerized by light, for example, ultraviolet rays, and can be used in any combination as long as they have different refractive indexes and appropriate compatibility, but if necessary, It is determined in consideration of the chemical and physical properties of the resin. As the photopolymerizable monomer or oligomer, those having an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, or the like in the molecule are preferable.

For example, polyester acrylate, polyol polyacrylate, modified polyol polyacrylate, isocyanuric acid skeleton polyacrylate, melamine acrylate, hydantoin skeleton polyacrylate, polybutadiene acrylate, epoxy acrylate, urethane acrylate, or bisphenol A diacrylate, 2,2-bis Polyfunctional acrylates such as (4-acryloxyethoxy-3,5-dibromophenyl) propane or methacrylates corresponding to these acrylates, or tetrahydrofurfuryl acrylate, ethylcarbitol acrylate, dicyclopentenyloxyethyl acrylate, Isobornyl acrylate,
Phenylcarbitol acrylate, nonylphenoxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, ω-hydroxyhexanoyloxyethyl acrylate, acryloyloxyethyl succinate, acryloyloxyethyl phthalate, phenyl acrylate, tribromophenyl acrylate, phenoxyethyl Acrylate, tribromophenoxyethyl acrylate, benzyl acrylate, p-
Bromobenzyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, 2,2,3,3-tetrafluoropropyl acrylate and methacrylates corresponding to these monofunctional acrylates, or styrene, p-chlorostyrene, divinylbenzene, vinyl Examples thereof include vinyl compounds such as acetate, acrylonitrile, N-vinylpyrrolidone and vinylnaphthalene, and allyl compounds such as diethylene glycol bisallyl carbonate, diarylidene pentaerythritol, triallyl isocyanurate, diallyl phthalate and diallyl isophthalate.

These compounds can be used either as monomers or after being made into oligomers.

In the present invention, at least two or more selected from these monomers or oligomers are used as a mixture, but the homopolymers must have different refractive indices. The resulting resin has a high haze ratio. Preferably, the at least two monomers or oligomers have a refractive index difference of at least 0.01, more preferably at least 0.05. The mixing ratio of at least two monomers or oligomers having a refractive index difference of 0.01 is 10: 90-90: 10 by weight.
It is preferably in the range of. The compatibility of these resins is preferably bad to some extent. If the compatibility is good, the resin obtained will be completely uniform and haze (white turbidity) will not occur. Further, if the compatibility becomes extremely poor, phase separation occurs before photo-curing, so that the haze ratio of the obtained resin is excessively reduced and the entire surface becomes haze.

The light control resin plate of the present invention is obtained by irradiating a mixture of the above-mentioned monomers or oligomers with light, preferably ultraviolet light, in the presence of a photopolymerization initiator. The photopolymerization initiator used here is not particularly limited, and any photopolymerization initiator used in ordinary photopolymerization may be used. Examples thereof include benzophenone, benzyl, Michler's ketone, 2-chlorothioxanthone, benzoin ethyl ether, diethoxyacetophenone, benzyl dimethyl ketal, 2-hydroxy-2-methylpropiophenone, and 1-hydroxycyclohexyl phenyl ketone.

The light control resin plate of the present invention is obtained by applying a mixture containing the above-mentioned monomer or oligomer and a photopolymerization initiator as a main component onto a substrate, or by providing two plate-like bodies transparent to irradiation light for photopolymerization. It is manufactured by encapsulating the mixture in a cell provided with a predetermined space and then curing the mixture by irradiating specific ultraviolet rays. The substrate used here may be any that is transparent to the ultraviolet light necessary to initiate photopolymerization. For example, a transparent glass, a flat plate made of plastic, or the like, or a template can be used. When a cell is used, both surfaces of the cell must pass the ultraviolet rays necessary for initiating photopolymerization, and transparent glass and plastic are preferable.

In the present invention, the film thickness of the resin mixture coated on the substrate or enclosed in the cell must be thick to some extent, and at least 50 μ is necessary, and the preferable film thickness is 100 μ, more preferably 200 μ or more. Is. That is, according to the present invention, a layer having a special structure that scatters only incident light from a specific direction is formed near the surface layer of the film cured by ultraviolet irradiation. It is considered that this layer has a structure in which plate-shaped bodies having different refractive indexes are arranged in parallel in a specific direction. Since the layer thickness is at least about 25 microns, the film thickness must be at least twice the layer thickness to form this layer on both sides of the film.

The uncured portion of the film, which is shielded from ultraviolet rays by both the first mask and the second mask, is then polymerized by ultraviolet rays or heat.

The ultraviolet lamp used in the production of the light control resin plate of the present invention is not particularly limited as long as it emits ultraviolet light, but a mercury lamp or a metal halide lamp is usually suitable in consideration of handling. Is.

<Advantages of the Invention> According to the present invention, an ultraviolet-curable light control plate, which has conventionally been capable of performing light control in a single direction and angle on the entire surface of one substrate, has a plurality of overlapping shapes and It has become possible to make a light control plate that has parts with different light control directions and angles.

<Examples> Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples.

Example 1 100 parts of polyether urethane acrylate (refractive index 1.481) consisting of polypropylene glycol, hydroxyethyl acrylate and isophorone diisocyanate, tribromophenoxyethyl acrylate (refractive index 1.567) 1
A mixture consisting of 00 parts and 6 parts of hydroxyisobutylphenone was poured between square glass plates (10 x 10 cm) having a distance of 1 mm, and the glass plate was shifted 45 degrees to the right from the vertical direction of the glass plates as shown in Fig. 1. A bar-shaped UV lamp (80 W / cm, 2 kw, lamp diameter 2 cm, lamp length 25 cm) is placed at an interval of 40 cm so that it is almost parallel to the side AB of the glass plate. Also, on the opposite side from the glass plate, another rod-shaped UV irradiation lamp of the same type is placed at a position shifted 45 degrees to the right from the vertical direction at a position 45 degrees to the right, and is parallel to side AB of the glass plate. Install so that. Photomasks X and Y in which the portion of letter X and the portion of letter Y transmit ultraviolet rays are respectively brought into contact with the front and back surfaces of the glass plate, and ultraviolet rays are simultaneously irradiated from the two lamps for about 1 minute (viewing angle A12. .
4 degrees, B1.0 degree). After that, the photomask X is removed, and frosted glass is placed instead of the photomask X, and ultraviolet rays are irradiated from above the glass plate in the vertical direction to cure the uncured portion with diffused light. By this operation, as shown in FIG. 4, when viewed from the front, it is transparent (2), when viewed from the left 45 degrees, the part of the character Y is opaque and many parts are transparent (1), when viewed from the right 45 degrees A light control plate in which the X portion is opaque and the other portion is transparent (3) can be manufactured.

In accordance with JIS K-6714, the total light transmittance and scattered light transmittance of the light control plate were measured by the integrating sphere type light transmittance measuring device for the parts X and Y of the characters and the parts other than the characters respectively, and the haze ratio (cloudiness value) was calculated. I asked. The above value was calculated by inclining the light control plate around an axis parallel to the side ab and allowing light to enter from a direction perpendicular to the side ab and changing the angle between the incident light and the light control plate. The angle dependence of the haze ratio is shown in FIG. Here, the dotted line represents the haze rate of the part corresponding to the letters X and Y, and the actual battle represents the haze rate of the part other than the letter.

Example 2 A mixture of 100 parts of bisphenol A type epoxy acrylate, 100 parts of tetrafluoroacrylate, 6 parts of benzyl dimethyl ketal and 3 parts of benzoyl peroxide was used to form two square glass plates (10 cm each) having a space of 1 mm.
Corners) and, as shown in FIG. 2, in the same manner as in Example 1 above with an interval of 40 cm in the vertical direction of this glass plate.
An 80 W / cm rod-shaped UV lamp is installed parallel to side AB of the glass plate. On the opposite side of the glass plate, another rod-shaped UV irradiation lamp is installed in parallel with side AB at a position shifted by 45 degrees to the left and right from the vertical direction with an interval of 40 cm. A photomask in which the letter X is on the front side of the glass plate and the letter Y is on the back side is a UV mask, and the UV rays are simultaneously irradiated from the three lamps for about 1 minute. Then, the photomask is removed, and the substrate is heated to 80 degrees to cure the uncured portion. By this operation, when viewed from the front as shown in FIG. 5, the part of the character X is opaque and the other part is transparent (2), and when tilted 45 degrees to the right or left from the front, the character Y is displayed.
A light control plate in which (1) and (3) was opaque, the other part was transparent, and the other part was always transparent was manufactured. Example 1
The result of measuring the haze ratio is shown in FIG. Here, the dotted line represents the haze ratio of the portion corresponding to the character X, the solid line represents the portion corresponding to the character Y, and the alternate long and short dash line represents the haze ratio of the portion other than the character.

Example 3 A UV curable light control plate composed of a mixture of 100 parts of polyether urethane acrylate consisting of polytetramethylene ether glycol, toluene diisocyanate and hydroxyethyl acrylate, 100 parts of tribromophenoxyethyl methacrylate and 6 parts of benzyl dimethyl ketal. The above raw material was poured between square glass plates (10 cm square) having a space of 1 mm, and as shown in FIG. 3, with a space of 40 cm in the vertical direction of the glass plate, the same as in Example 1.
An 80 W / cm rod-shaped UV lamp is installed parallel to side AB of the glass plate. In addition, 40 on the opposite side when viewed from the glass plate in the vertical direction.
Install another rod-shaped UV irradiation lamp parallel to the side AB of the glass plate with a space of cm. Place a photomask on the surface of the glass plate where the letter X transmits ultraviolet light, place a photomask of the same shape on the back surface at the same position, slightly offset from the front side, and simultaneously apply ultraviolet light from two lamps for about 1 minute. Irradiate. After that, the photomask on the front surface side is removed, rubbing glass is placed, and ultraviolet light (diffused light) is irradiated from above the glass plate in the vertical direction to cure the uncured portion. By this operation, when viewed from the front, the portion of the letter X was opaque on both the front and back sides, a deep mask pattern with increased decorativeness was drawn, and a light control plate that was transparent when tilted to the left or right was produced. The result of measuring the haze ratio is shown in FIG. 9 as in Example 1. Here, the dotted line represents the haze ratio of the portion corresponding to the letter X, and the solid line represents the haze ratio of the portion other than the letter X.

[Brief description of drawings]

1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a perspective view showing another embodiment of the present invention, FIG. 3 is a perspective view showing yet another embodiment, FIG. FIG. 5 is a perspective view showing the optical characteristics of the light control plates of these examples, FIG. 6-FIG. 8 is a graph showing the optical characteristics of the light control plates of these examples, and FIG.
FIG. 14 is a schematic diagram illustrating the present invention. 1 ... UV lamp, 2 ... glass plate 3 ... resin composition, 4 ... spacer 5 ... photomask

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Shiiki 4-chome, Doshomachi, Higashi-ku, Osaka, Osaka Prefecture Japan Sheet Glass Co., Ltd. (72) Inventor Hisato Kabuki 4-chome, Doshomachi, Higashi-ku, Osaka, Japan Japan Ita Glass Co., Ltd. (72) Inventor Motoaki Yoshida 4-8 Doshomachi, Higashi-ku, Osaka City, Osaka Prefecture Japan Ita Glass Co., Ltd. (72) Inventor Shinichiro Kitayama 3-1, 98 Kasuga, Konohana-ku, Osaka City, Osaka Prefecture Sumitomo Chemical Co., Ltd. (72) Inventor Teruho Adachi 3-1,98 Kasugade, Konohana-ku, Osaka City, Osaka Prefecture Sumitomo Chemical Co., Ltd. (72) Inventor, Masahiro Ueda Kasuga, Konohana-ku, Osaka City, Osaka Prefecture 3-1-98 Sumitomo Chemical Co., Ltd. (56) Reference JP 62-70407 (JP, A) JP 60-247515 (JP, A) JP 51 74425 (JP, A)

Claims (1)

(57) [Claims] 1. A resin composition containing at least two kinds of photopolymerizable oligomers or monomers having different refractive indexes is maintained in a film form, and the film form is irradiated with light from a specific direction to be cured. Thus, in the method for manufacturing a light control plate having a function of scattering incident light in a predetermined angle range, a photomask having a first shape is arranged between the first linear light irradiation source and the film body. And irradiate light from the irradiation source at the same time, and at the same time, a second linear light irradiation source is installed on the opposite side of the annular body from the first light irradiation source, A method for manufacturing a light control plate, characterized in that a photomask having a second shape is arranged between the body and the light and the light is irradiated from a second irradiation source.