JP2547419B2 - 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 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 and angle. For example, in the case of the above-mentioned micro louver, in order to widen the non-perspective angle, the transparent layer must be narrowed or the plate thickness must be increased. In order to narrow the transparent layer, it is necessary to reduce the thickness of the transparent film to be laminated and to narrow the etching by the resist, and both have limitations, and in either case, the amount of transmitted light decreases. On the other hand, increasing the thickness of the plate makes handling of the plate itself inconvenient, increases the raw material cost, and reduces the amount of transmitted light.

Another UV-curing light control plate can make only one non-perspective direction, and its angle is relatively narrow. For example, it is difficult to manufacture a light control plate that is transparent on the front side and becomes opaque when tilted in either direction, or a light control plate having an opaque angle of ± 30 degrees or more when viewed from the front side.

<Means for Solving Problems> In order to solve the above-mentioned conventional problems, the present invention maintains a resin composition composed of an oligomer or a monomer having a difference in refractive index of photopolymerization or a mixture thereof in a film form. Then, by curing it by irradiating it with ultraviolet rays from a specific direction, in the production of a light control plate having a function of scattering only light in a predetermined range, ultraviolet rays are irradiated from a plurality of irradiation sources, and the photopolymerizable resin composition By curing the material, it became possible to increase the number of light control directions and expand the light control angle.

That is, the present invention, by maintaining a resin composition containing a photopolymerizable oligomer or monomer having a difference in refractive index in a film form, by irradiating the film form with light from a predetermined direction to cure the composition, In a method of manufacturing a light control plate having a function of scattering incident light within a predetermined angle range, a plurality of light control plates are provided by simultaneously irradiating the film-like body with light from a plurality of linear irradiation light sources arranged apart from each other. The method for producing a light control plate is characterized in that the light scattering angle can be increased or the light scattering angle can be increased.

The method for installing a plurality of linear irradiation sources used in the present invention is
It is appropriately set according to the direction and angle of light control required for the manufactured light control plate. However, the maximum haze ratio decreases as the number of irradiation sources increases. In the present invention, when a plurality of linear irradiation light sources are arranged in parallel with each other, it is preferable that the light sources are separated so as to have a viewing angle of at least 10 degrees when viewed from the irradiation surface. If a large number of light sources are arranged without being separated, selective light scattering will no longer be obtained, as will be described later.

In the present invention, the film-like body is simultaneously irradiated with light from a plurality of linear irradiation light sources arranged apart from each other, but if irradiation is performed from a plurality of linear irradiation light sources at different times,
Since the film is cured by the previously irradiated light, the light control plate cannot have a plurality of light scattering angles or an increased light scattering angle.

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. 6, a layer 13 having a microstructure is formed inside the film 11 near the irradiated 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. 7 which is a plan view and FIG. 8 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. 9 which is a sectional view taken along the line AA in FIG. 7, 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. 10, but also the light incident on the film including the light ray having the incident angle Y1 or Y2 and passing through the plane 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.

In the present invention which irradiates the film-like body with light simultaneously from a plurality of linear irradiation light sources arranged apart from each other, as the minute pieces of the above-mentioned microstructure layer, the inclination angle is the direction of the ray from each irradiation light source. Are likely to be mixed, so that the light control plate has a plurality of light scattering angles or an increased light scattering angle.

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 FIG. 6, the microparticles 14 and the substance 16 between them are probably different in refractive index (this different refractive index is the refractive index of the photopolymerizable oligomer or monomer used as a 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 oligomer or monomer used in the present invention is a polymer which is polymerized by ultraviolet rays, and any combination can be used as long as it has a different refractive index and an appropriate compatibility, but if necessary, a resin may be used. It is determined in consideration of the chemical and physical properties of. 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, diallylidene 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 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 the mixture of the above monomers or oligomers with ultraviolet rays 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. For example,
Benzophenone, benzyl, Michler's ketone, 2-chlorothioxanthone, benzoin ethyl ether, diethoxyacetophenone, benzyl dimethyl ketal, 2
-Hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone and the like can be mentioned.

The light control resin plate of the present invention is manufactured by coating a mixture containing the above-mentioned monomer or oligomer and a photopolymerization initiator as a main component on a substrate or enclosing the mixture in a cell and then curing it by ultraviolet rays. 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 not particularly limited as long as it emits ultraviolet rays, but usually a mercury lamp or a metal halide lamp is suitable in consideration of easy handling. Is.

<Effects of the Invention> According to the present invention, an ultraviolet curable light control plate, which has conventionally been able to scatter light only in a narrow angle range in one direction, can be controlled in a wide angle range or in a plurality of directions on a single substrate. It became possible to make it a control board.

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

[Measurement of parallel light transmittance and haze value] According to JIS K-6714, total light transmittance and scattered light transmittance were measured by an integrating sphere light transmittance measuring device to obtain parallel light transmittance and haze value (haze ratio). .

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) 100 parts, 100 parts of tribromophenoxyethyl acrylate (refractive index 1.567), and 6 parts of hydroxyisobutylphenone are used to inject the raw material for the UV-curable light control plate between the glass plates having a space of 1 mm, First
As shown in the figure, a spacer 4 is injected between two square glass plates 2 and 10 cm × 10 cm, which are horizontally placed at a distance of 1 mm to form a film-like body 3.

Two rod-shaped UV lamps 1 (80W / cm, 2K) 40cm apart from the center of the glass plate in the vertical direction at intervals of 40cm
W, diameter 2 cm, light emission length 25 cm) are installed horizontally and parallel to each other and parallel to side ab of the glass plate. At the same time, ultraviolet rays are emitted. By this operation, a light control plate with a non-transparent angle about 1.5 times (± 30 degrees) wider than when using one ultraviolet lamp was obtained.

Example 2 A raw material of an ultraviolet curable light control plate composed of a mixture of 100 parts of bisphenol A type epoxy acrylate, 100 parts of tetrafluoroacrylate and 6 parts of benzyl dimethyl ketal was injected between glass plates having a space of 1 mm. As shown in Figure 2, from the vertical direction of the glass plate to the left and right
The same ultraviolet irradiation device as in Example 1 was installed in parallel at positions shifted by 45 degrees, and ultraviolet rays were simultaneously irradiated. This operation makes it possible to manufacture a light control plate that is transparent when viewed from the front and becomes opaque when tilted 45 degrees to the right or left from the front.

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. Pour the raw material of the above into the space between the glass plates with a space of 1 mm, and as shown in Fig. 3, move vertically from the glass plates.
The same rod-shaped UV lamp as in the example is installed with an interval of 40 cm, and two UV irradiation devices are installed in parallel at positions 60 degrees left and right from the vertical direction of the glass plate.
Simultaneously irradiate with ultraviolet rays. By this operation, it is possible to manufacture a light control plate that is opaque when viewed from the front, becomes transparent when tilted about 30 degrees to the right or left from the front, and becomes opaque when tilted further up to 60 degrees.

The light transmittance and haze ratio of the above examples are shown in Table 1, and these numerical values are shown in FIGS. 1 to 3 with the perpendicular direction from the center of the glass plate to the glass plate at an angle of 0 degree, and the left side It is measured as minus and plus on the right side.

Example 4 Two square glass plates (10 × 10 5) were prepared by using the same raw material for the UV curable light control plate as in Example 1 with a 1 mm thick spacer interposed therebetween.
cm), and as shown in Fig. 4, four ultraviolet lamps (80W / cm, 2KW, lamp diameter 2cm, lamp length 25cm) were placed 40cm vertically from the glass plate in a cross shape, At the same time, ultraviolet rays were irradiated for 1 minute. The obtained resin plate was opaque when it was tilted to the front, up, down, left, and right, but became transparent when tilted obliquely (upper right, etc.).

FIG. 5 shows a method for measuring the haze ratio of the present resin plate. The haze ratio was measured from the z-axis direction by rotating around the x-axis or the y-axis with 0 ° when viewed from the front. Table 2 shows the measurement results.

COMPARATIVE EXAMPLE Two square glass plates (10 × 10 4) with the same raw material of the UV curable light control plate as in Example 1 sandwiching a 1 mm thick spacer were used.
cm, and one ultraviolet lamp (80 W / cm, 2 KW, lamp diameter 2 cm, lamp length 25 cm) was placed 40 cm vertically from the glass plate and irradiated with ultraviolet rays for 1 minute. The resin plate obtained is opaque when viewed from the front. However, when it was tilted 30 degrees to the left and right, it looked transparent. Table 1 shows the measurement results of the haze ratio.

[Brief description of drawings]

1 to 4 are perspective views showing an embodiment of the present invention, FIG. 5 is a perspective view showing a haze ratio measuring method of an embodiment 4 of the present invention, and FIGS. It is a schematic diagram explaining. 1. UV lamp, 2. Glass plate 3. Resin composition film, 4. Spacer

Front page continuation (72) Inventor Satoshi Shiiki 4-chome, Doshomachi, Higashi-ku, Osaka-shi, Osaka, Japan Sheet Glass Co., Ltd. (72) Inventor Hisato Katsuki 4-chome, Dosho-cho, Higashi-ku, Osaka, Osaka Japan Sheet Glass Co. (72) Inventor Motoaki Yoshida 4-chome, Doshomachi, Higashi-ku, Osaka City, Osaka Prefecture Nippon Sheet Glass Co., Ltd. (72) Inventor Shinichiro Kitayama 3-98, Kasugade, Konohana-ku, Osaka-shi, Osaka Sumitomo Chemical Co., Ltd. Co., Ltd. (72) Inventor Teruho Adachi 3-1-1 Kasugade, Konohana-ku, Osaka City, Osaka Prefecture Sumitomo Chemical Co., Ltd. (72) Inventor Masahiro Ueda 3-chome, Kasugade, Konohana-ku, Osaka City, Osaka Prefecture No. 98 in 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 a photopolymerizable oligomer or monomer 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 a method for manufacturing a light control plate having a function of scattering incident light in a predetermined angle range, a plurality of linear irradiation light sources arranged apart from each other are used to irradiate light onto the film-like body at the same time. And a method of manufacturing a light control plate having an increased light scattering angle.