JP2547417B2 - Method of manufacturing light control plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an ultraviolet curing type angle dependency that selectively scatters only incident light from a predetermined angle range and transmits incident light of other angles. The present invention relates to a method for manufacturing a light control plate.

<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 long axis and short axis directions of the ultraviolet light source, and only when the film-shaped cured product is rotated about the long axis direction of the light source as a predetermined angle range. Scatter light. 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 and angle. For example, in the case of the above-mentioned micro louver, if one tries to fabricate a light control plate capable of performing light control in various directions by dividing one substrate into several parts, several light control directions are Different substrates must be cut out and combined, or the etching direction by the resist must be changed, both of which are very complicated and difficult, and the manufacturing cost is high.

In addition, the light control plate formed by this ultraviolet curing can only make one non-perspective direction. For example, a portion of the substrate is transparent at the front and becomes opaque when tilted in either direction, and the rest has the opposite function, or the first portion of the substrate is opaque when viewed from the front and is tilted at either angle. Transparent and second
It has not been possible in the past to fabricate a light control plate in which the portion of is always opaque and the rest is always transparent.

<Means for Solving Problems> In order to solve the above conventional problems, the present invention forms a resin composition containing at least two kinds of photopolymerizable oligomers or monomers having a difference in refractive index into a film form. In the method for producing a light control plate having a function of scattering and maintaining incident light in a predetermined angle range by curing by irradiating the film with light, for example, ultraviolet rays from a predetermined direction. The surface is divided into a plurality of regions, and at least one region is irradiated with light from the linear light irradiation source, and at least one region is irradiated with (A) a linear light irradiation source from a different angle from the irradiation source. (B) Light from a point light source or parallel light, (C) Diffuse light, or (D) Heat is applied to cure the area and scatter. Various with different angle range A method for producing a light control plate, characterized in that to have a region in the film-like body.

Hereinafter, the method for manufacturing the light control plate of the present invention will be described more specifically.

The method for producing a light control plate of the present invention comprises applying a resin composition containing a photopolymerizable, mixture of oligomers or monomers having a difference in refractive index and a photopolymerization initiator onto a substrate or in a plate cell. To maintain a film-like shape by encapsulating the film, and to divide the surface of the film-like body into a plurality of regions by, for example, covering it with a photomask, and at least one region, for example, a portion facing the opening of the photomask, Of the second linear light irradiation source from a different angle from the irradiation source to other at least one region, for example, the portion covered with the photomask. By irradiating and curing, and if there is an unirradiated part after that, curing is completed by light or thermal polymerization, so that a light control plate having various regions with different scattering angle ranges in a film-like body can be obtained. To be Instead of the light from the second linear light irradiation source, light from a point light source or parallel light may be applied, diffused light may be applied, or heat may be applied. The irradiation of the light of the first linear light irradiation source and the irradiation of the light of the second linear light irradiation source (or the irradiation of other light) may be performed at the same time, or either one may be performed first. May be. However, since it is generally difficult to accurately determine the curing area by heat application, when an accurate curing area is required, heat application curing is performed after irradiation of light from the first linear irradiation source. Is preferably performed.

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 of various incident angles show a mountain-shaped graph shape that is the maximum near the incident angle of Z.

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 methyl acrylate, tetrahydrofurfuryl acrylate, ethyl carbitol 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,
Vinyl compounds such as divinylbenzene, vinyl acetate, acrylonitrile, N-vinylpyrrolidone, and vinylnaphthalene, or allyl compounds such as diethylene glycol bisallyl carbonate, dialylidenepentaerythritol, triallyl isocyanurate, diallyl phthalate, and diallyl isophthalate. can give. 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 resulting resin will be completely uniform and no haze will occur. Further, if the compatibility becomes extremely poor, phase separation occurs before photocuring, so that the haze ratio of the obtained resin is excessively reduced, resulting in haze over the entire surface.

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 coated with a mixture containing the above-mentioned monomer or oligomer and a photopolymerization initiator as a main component, or sealed in a plate-shaped cell, and then cured by the above-mentioned specific ultraviolet irradiation. Manufactured. The substrate used here may be any substrate as long as the surface of the applied film can be smoothed. For example, a flat plate or template of glass, plastic, metal or the like can be used. When a cell is used, at least one surface of the cell must transmit ultraviolet rays necessary for starting photopolymerization, and transparent glass, plastic, and the like are preferable.

The ultraviolet lamp used for producing the light control resin plate of the present invention is particularly limited as long as it emits ultraviolet rays, except for the above-mentioned linear irradiation light source for obtaining a film showing selective light scattering properties. However, a mercury lamp or a metal halide lamp is usually preferable in consideration of easy handling.

<Effects 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 different angle range for scattering on one substrate. It has become possible to make a light control plate with various regions.

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

Example 1 Polyether urethane acrylate composed of polypropylene glycol having an average molecular weight of 2000, hydroxyethyl acrylate and isophorone diisocyanate (refractive index 1.
481) A resin composition consisting of 100 parts, 100 parts of tribromophenoxyethyl acrylate (refractive index 1.567) and 6 parts of hydroxyisobutylphenone was placed horizontally with a spacer 5 at a distance of 1 mm as shown in FIG. 10 cm x
It is injected between two 10 cm square glass plates 4 and 4 to form a film-like body 3. , 40 in the direction perpendicular to the center of the glass plate surface
Ultraviolet lamps 1 (80W / cm, 2K)
W, diameter 2 cm, emission length 25 cm) horizontally and side of glass plate
Install so that it is parallel to ab. A photomask 7 having a transmissive portion of the letter A is placed on the surface of a glass plate, and ultraviolet rays are irradiated from the lamp 1 (viewing angles A17.4 degrees and B1.4 degrees), and the portion of the film-shaped resin composition corresponding to the letter A Cure. After that, the photomask 7 is removed, and as shown in FIG. 2, one UV lamp 1 is placed at a height of 40 cm from the glass plate surface and is shifted 45 degrees to the left and right from the vertical direction of the glass plate. 1 is installed horizontally and parallel to each side ab, and is irradiated with ultraviolet rays at the same time (viewing angle A12.4 degrees, B1.0
The uncured film portion other than the letter A is cured. By this operation, a light control plate composed of two glass plates and a film-shaped resin sandwiched between the glass plates can be obtained. When the control plate is viewed from the front and tilted above or below the front so that the side ab is on the left side and the side cd is on the right side, the portion of the letter A that is exposed to the ultraviolet light is It is opaque and the other part is transparent, and when it is tilted 45 degrees to the right or left from the front, the part of character A appears transparent and the other part appears opaque. Both parts appear transparent when tilted about 22 degrees to the right or left of the front or tilted more than about 70 degrees to the right or left of the front.

In accordance with JIS K-6714, the total light transmittance and scattered light transmittance of the light control plate were measured for the part of the letter A and the part other than the letter A by the integrating sphere type light transmittance measuring device to obtain the haze rate (cloudiness value). It was 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 ratio of the portion corresponding to the letter A, and the solid line represents the haze ratio of the portion other than the letter A.

Example 2 A resin composition consisting of 100 parts of polyether urethane acrylate consisting of polytetramethylene ether glycol, toluene diisocyanate and hydroxyethyl acrylate, 100 parts of tribromophenyl methacrylate, 6 parts of benzyl dimethyl ketal and a 1 mm thick spacer sandwiched horizontally It is poured between two 20 cm x 20 cm square glass plates to form a film, and the letters are printed on the surface of each glass plate.
Three opaque seals 8 shaped A, B and C were attached. As shown in Fig. 3, put a glass plate with a sticker horizontally, place the frosted glass plate 6 on the glass plate, and keep the rod horizontal high pressure mercury lamp (80W / cm, 2KW, diameter 2cm, emission length) 2
(5 cm) was placed at a distance of 40 cm, and turned on for 1 minute to irradiate the film with scattered light of ultraviolet rays. Next, remove the frosted glass plate, peel off the seal A, and use the same UV lamp from directly above the original seal A so that its length direction is parallel to the side ab of the glass plate. The film-like part was cured by irradiating it with ultraviolet rays for 1 minute (viewing angle A17.4 degrees, B1.4
Every time). Next, the seal B was peeled off, and as shown in FIG. 5, ultraviolet rays were similarly irradiated from a position shifted in parallel to the left by 45 degrees. Finally, the seal C is peeled off, and as shown in FIG. 6, a point-like ultra-high pressure mercury lamp (light emission size 2 cm x 2
UV light of 40 cm) was irradiated for 2 minutes from a distance of 40 cm (viewing angle A
1.4 degrees, B1.4 degrees). In the obtained light control plate, the part of the letter A is cloudy when viewed from the front, is transparent when viewed from a position more than 30 degrees to the left and right from the front, and the part of the letter B is viewed from the front to the left. It was cloudy when viewed from a position 45 degrees away, and transparent when viewed from a position more than 30 degrees to the left and right. The portion of the letter C was cloudy when viewed from any angle. The parts other than the letters A, B, and C were transparent from any angle. Note that the visible state does not change even when tilted in the vertical direction, and the visible state is determined only by the horizontal tilt. FIG. 8 shows the angle dependence of the measured haze ratio. Here the dotted line corresponds to the letter A, the actual battle is the letter B
And the one-dot chain line represent the haze ratio of the portion corresponding to the letter C, respectively.

[Brief description of drawings]

1 and 2 are perspective views showing an embodiment of the present invention,
FIGS. 3 to 5 are perspective views showing another embodiment 2, FIGS. 6 and 8 are graphs showing the optical characteristics of the light control plates of these embodiments, and FIGS. 9 to 14 show the present invention. It is a schematic diagram explaining. 1 ... High pressure mercury lamp, 2 ... Ultra high pressure mercury lamp 3 ... Resin composition, 4 ... Sheet glass 5 ... Spacer, 6 ... Frosted glass 7 ... Photo mask, 8 ... Character seal

 ─────────────────────────────────────────────────── ─── 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 a difference in refractive index is maintained in a film form, and the film form is irradiated with light from a predetermined direction to be cured. In the method of manufacturing a light control plate having a function of scattering incident light in a predetermined angle range by dividing the surface of the film-like body into a plurality of regions, at least one region from the linear light irradiation source Of the linear light irradiation source from a different angle from the irradiation source, and (B) the light from the point light source or the parallel light is irradiated onto at least one other area. , (C) diffused light is irradiated, or (D) heat is applied to cure the region, so that the film-shaped body has various regions having different scattering angle ranges. Control board manufacturing method.