JP2837239B2 - Manufacturing method of light control plate with light scattering transparent region - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a light control plate having a light-scattering transparent region and a light-straight-transmitting region.

<Prior Art> Conventionally, only a transparent body made of plastic or glass was transparent to light from any angle. By the way, as a material that transmits only light from a specific angle, grids and stripes are formed on a transparent substrate using an alignment film or photosensitive resin cut out of a plastic block in which plastic transparent sheets and opaque sheets are laminated alternately. In general, a so-called "light-shielding plate" in which a relief having the pattern shown in FIG. Such a light shielding plate is proposed in Japanese Patent Application Laid-Open No. 57-189439.

These conventional alignment films and light-shielding plates are expensive because of their complicated manufacturing methods, and have a problem that the quality of the alignment films is not uniform.

JP-A-64-40902 discloses that a resin composition containing at least two kinds of photopolymerizable oligomers or monomers having a difference in refractive index is maintained in the form of a film, and the film is formed from a specific direction. In a method for manufacturing a light control plate having a function of scattering incident light within a predetermined angle range by irradiating and curing light, a first linear light irradiation source and a film-like body are provided.
A photomask having the shape of is arranged and light is irradiated from the irradiation source, and at the same time, a second linear light irradiation source is installed on the film body on the side opposite to the first light irradiation source. Discloses a method of arranging a photomask having a second shape between a second irradiation source and a film-shaped body and irradiating light from the second irradiation source.

JP-A-64-40903 discloses a method of manufacturing a light control plate in the same manner as described above, in which the surface of a film is divided into a plurality of regions, and at least one region is irradiated with a linear light irradiation source. And irradiates at least one other area with
(A) irradiating light of a linear light irradiation source from an angle different from the irradiation source, (B) irradiating light or parallel light from a point light source, (C) irradiating diffused light, or (D)
A method for applying heat is disclosed.

Japanese Patent Application Laid-Open No. 64-77001 discloses a light control plate made of a plastic sheet that selectively scatters only incident light at a specific angle and a method of manufacturing the same.

In the above manufacturing method, a rod-shaped lamp is used as a light source. The resin plate cured by light irradiation shows anisotropy in the major axis and minor axis directions of the light source, and scatters light in a predetermined angle range only when rotated around the major axis direction of the light source. In other words, it is considered that the generated resin plate has regions having different refractive indexes oriented in a certain direction, and light incident from a specific angle is scattered by this structure.

Moreover, as described in the above-mentioned publication, the light control plate has a part of the substrate which is transparent in the front and becomes opaque when inclined in any direction, and the other part has a function opposite to that of the substrate or the substrate. The first part is opaque when viewed from the front and is transparent at any angle, the second part is always opaque,
It is also possible to produce a light control plate whose remaining part is always transparent.

According to the method described in the above publication, 1
A photopolymerizable composition having at least two polymerizable carbon-carbon double bonds and containing at least two compounds having different refractive indices is maintained in the form of a film, and light is emitted to the film from a specific direction. In the method of irradiating and curing, a part of the surface of the film is divided into a plurality of regions by covering the surface with, for example, a photomask. Irradiates light from the linear light irradiation light source, and irradiates at least one other region, for example, a portion covered with a photomask, with light from the second linear light irradiation source from a different angle from the irradiation source. After that, if there is an unirradiated portion, the curing is completed by light or thermal polymerization to obtain a light control plate having various regions having different scattering angle ranges in the film.

Instead of the light from the second linear light irradiation source, light from a point light source or parallel light, diffused light, or heat may be applied.

If a point light source or parallel light is applied, the region cured later becomes a uniform ground glass, and only the region cured by the first light source becomes a light control film having an angle dependence.

When the diffused light is irradiated, only the region cured by the first light source has an angle dependency, and the region cured later becomes a transparent light control plate. According to the above-described conventional method, it is possible to manufacture a light control plate having various regions in which the angle range of scattering within one resin plate is clearly different.

<Problem to be Solved by the Invention> It is an object of the present invention to provide a method for manufacturing a light control plate having a light scattering transmission region and a straight light transmission region.

It is another object of the present invention to provide a method of manufacturing a light control plate in which a light-scattering / transmissive region scatters and transmits only incident light at a specific angle and straight-transmits incident light at other angles.

Still another object of the present invention is to provide a method for industrially producing a light control plate having the above-mentioned light scattering and transmitting region.

Still another object of the present invention is to provide a light control plate which can not be manufactured by the conventional batch method and can easily manufacture a light control plate over a relatively wide range in which only a specific angle of incident light is scattered and transmitted. It is to provide a continuous manufacturing method.

It is still another object of the present invention to provide a method for continuously producing a light control plate on which a light scattering transmission pattern is clearly transferred, particularly in the long axis direction of a linear light source.

It is still another object of the present invention to provide a method for manufacturing a light control plate in which a light-scattering and transmitting region scatters and transmits incident light at any angle.

Still other objects and advantages of the present invention will be apparent from the following description.

<Means for Solving the Problems> According to the present invention, such objects and advantages of the present invention are as follows.
First, (1) From a film of a photopolymerizable composition and a light-transmitting member provided along a surface of the film and having a light-scattering / transmitting pattern for scattering and transmitting light and a portion for directly transmitting light. Wherein the photopolymerizable composition comprises: (a) at least two monomers having a polymerizable carbon-carbon double bond and capable of producing a polymer having a different refractive index; A mixture, (b) at least one monomer having a plurality of polymerizable carbon-carbon double bonds in a molecule, and (c) a compound having no polymerizable carbon-carbon double bond and a polymerizable carbon-carbon double bond. A mixture of at least one monomer having a heavy bond and capable of forming a polymer having a refractive index different from that of the compound; and (2) the presence of the light transmitting member in the assembly. [1] The above light A linear light source having a long axis positioned substantially parallel to the surface of the film of the composition, or [2] irradiating light from a point light source or a parallel light source to polymerize the photopolymerizable composition of the film. (A) a region defined by the light scattering transmission pattern, which allows incident light of any angle to travel straight through; and (b) a light from the linear light source, defined by a portion which allows the light to travel straight through. In the case of irradiating the light, a region in which only incident light at a predetermined angle is scattered and transmitted and the incident light at other angles is transmitted straight through, or when irradiating light from the point light source or the parallel light source, any angle is used. The light control plate is provided with a region that also scatters and transmits the incident light of the light control plate.

According to the method of the present invention, first, in step (1), that is, in the first step, a film of the photopolymerizable composition and a light transmission having a predetermined light scattering / transmitting pattern arranged along the surface of the film. An assembly consisting of the body is prepared.

The photopolymerizable composition contains a photopolymerizable unsaturated compound having a polymerizable carbon-carbon double bond. Such a photopolymerizable composition comprises: (a) a mixture of at least two types of monomers having a polymerizable carbon-carbon double bond and capable of producing polymers having different refractive indices; (C) a compound having no polymerizable carbon-carbon double bond and (c) a compound having no polymerizable carbon-carbon double bond and having a polymerizable carbon-carbon double bond. It is selected from a mixture of at least one monomer capable of producing a polymer having a refractive index different from the refractive index.

The monomer constituting the mixture (a) has a polymerizable carbon-carbon double bond. Suitable examples of the polymerizable carbon-carbon double bond include an acryloyl group, a methacryloyl group, a vinyl group and an allyl group.

Examples of such a monomer include polyester acrylate, polyol polyacrylate, modified polyol polyacrylate, isocyanuric acid skeleton polyacrylate, melamine acrylate, bidant-in skeleton polyacrylate, polybutadiene acrylate, epoxy acrylate, urethane acrylate, and bisphenol A.
Multifunctional acrylates such as diacrylate and 2,2-bis (4-acryloxyethoxy-3,5-dibromophenyl) propane or methacrylates corresponding to these acrylates: methyl acrylate, tetrahydrofurfuryl acrylate, ethyl carbitol Acrylate, dicyclopentenyloxyethyl acrylate,
Isobornyl acrylate, phenyl carbitol 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: styrene, p-chlorostyrene, divinylbenzene, vinyl acetate, acrylonitrile,
Vinyl compounds such as N-vinylpyrrolidone and vinylnaphthalene: and allyl compounds such as dimethylglycol bisallyl carbonate, dialylidenepentaerythritol, triallyl isocyanurate, diallyl phthalate and diallyl isophthalate.

These compounds can be used as monomers or as oligomers.

In the mixture of the above (a), at least two kinds of the above monomers are used. These monomers need to be in a combination to give homopolymers having different refractive indexes. A combination of monomers giving a homopolymer having a large difference in refractive index is more preferable. It is advantageous to use a combination of monomers giving two homopolymers whose refractive index difference is for example at least 0.01, more preferably 0.05.

When three or more types of monomers are used, a combination of monomers in which the difference in the refractive index of at least two of the homopolymers is 0.01, more preferably 0.05 is used. Is desirable.

In the above mixture (a), the two monomers having the largest difference in the refractive index of the homopolymer are in a polymerization ratio of 10:90 to 90:
Used at a rate of 10.

It is preferable that at least two kinds of homopolymers obtained from at least two kinds of monomers have insufficient compatibility with each other. If the compatibility is too high, the resulting resin will be completely uniform and no haze will occur. On the other hand, if the compatibility becomes extremely poor, phase separation occurs before the photocuring, so that the haze ratio of the obtained resin becomes too high, and the entire resin becomes haze, making it difficult to exhibit a light control function at all.

The mixture of the above (a) can contain a photopolymerization initiator as needed.

The photopolymerization initiator is not particularly limited, and may be any one used in ordinary photopolymerization. For example, benzophenone, benzyl, Michler's keto, 2-chlorothioxanthone, benzoin ethyl ether, diethoxyacetophenone, benzyldimethyl ketal, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone and the like can be mentioned.

The mixture of the above (a) can be prepared by stirring and mixing at least two kinds of monomers and, if necessary, a photopolymerization initiator.

Examples of the monomer having a plurality of polymerizable carbon-carbon double bonds in the molecule constituting the polymerizable composition (b) include, for example, acryloyl group, methacryloyl group, vinyl group and allyl group. Compounds having a plurality of groups in the molecule as polymerizable carbon-carbon double bonds are advantageously used.

Such compounds include, for example, triethylene glycol diacrylate, polyethylene glycol diacrylate, neopentyl glycol diacrylate, 1,6
-Hexanediol diacrylate, hydrogenated dicyclopentadienediyl diacrylate, ethylene oxide-modified bisphenol A diacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, trisacryloxyisocyanurate, polyfunctional epoxy acrylate, polyfunctional epoxy acrylate Examples include urethane acrylic sheets, methacrylates corresponding to these acrylates, divinylbenzene, triallyl isocyanurate, and diethylene glycol bisallyl carbonate.

These compounds can be used as monomers or as oligomers.

As such a compound, a compound having a difference between the refractive index before curing by light irradiation and the refractive index of the resin after curing of at least 0.01, more preferably at least 0.02, is advantageously used.

Such compounds may be used alone or as a mixture of two or more, and if necessary, as a mixture with a photopolymerization initiator.
Can be used. As the photopolymerization initiator, the same ones as described above for the composition (a) can be used.

Further, the mixture (c) produces a compound having no polymerizable carbon-carbon double bond and a polymer having a polymerizable carbon-carbon double bond and having a refractive index different from that of the compound. And at least one monomer obtained.

The above compound having no polymerizable carbon-carbon double bond means a compound having no polymerizable carbon-carbon double bond such as an acryloyl group, a methacryloyl group, a vinyl group or an allyl group in a molecule.

Such compounds include, for example, polymers such as polystyrene, polymethyl methacrylate, polyethylene oxide, polyvinyl pyrrolidone, polyvinyl alcohol, and nylon: toluene, n-hexane, cyclohexane, methyl alcohol, ethyl alcohol, acetone,
Low molecular weight compounds such as methyl ethyl ketone, tetrahydrofuran, ethyl acetate, dimethylformamide, dimethylacetamide and acetonitrile: or organic additives such as organic halogen compounds, organic silicon compounds, plasticizers and stabilizers.

Further, as the above-mentioned monomer constituting the mixture (c),
The same ones as described for the mixture (a) and the polymerizable composition (b) can be used.

The compound having no polymerizable carbon-carbon double bond and the monomer having the bond, which constitute the mixture (c), are preferably such that the monomer having the bond is the total weight of the compound and the monomer. A proportion occupying 10 to 99% by weight, more preferably 50 to 95% by weight based on the same basis,
Is advantageously used.

Further, the compound having no polymerizable carbon-carbon double bond and the monomer having the bond, the difference between the refractive index of the compound and the refractive index of the homopolymer of the monomer is at least 0.01. Certain combinations are preferred, and even more preferred are combinations that are at least 0.02.

In the step (1) of the present invention, the photopolymerizable composition as described above is coated on a substrate such as a glass plate and formed into a film having a predetermined length and width. Along the surface of this film. A light transmitting body having a predetermined light scattering and transmitting pattern is arranged. Thus, an assembly comprising a film of the photopolymerizable composition and a light transmitting body having the pattern is prepared.

The light-transmitting body provided with the pattern is, for example, a substrate provided with a light-scattering / transmitting pattern by providing fine irregularities on a part of the surface of the light-transmitting substrate itself, and a light-scattering / transmitting pattern on the substrate itself. A substrate having an object having a light-scattering / transmitting pattern, or a substrate on which an object having a light-scattering / transmitting pattern is provided (preferably 3 mm from the substrate surface)
It is advantageous to use an object that is located within a distance of

The film of the photopolymerizable composition making up the assembly preferably has a thickness of at least 25 μm, more preferably at least 100 μm, particularly preferably at least 200 μm.

According to the method of the present invention, in the step (2), that is, the second step, the assembly is irradiated with light from the side where the light transmitting body exists. Here, as a light source for emitting light, any of a linear light source, a point light source, and a parallel light source can be used. When the light irradiation source is a linear light source, the illuminated film portion becomes scattered light through a portion of the light transmitting body that scatters and transmits light, and is cured to transmit light straight. In other words, the cured film section gives a clear view from any angle. On the other hand, the film portion irradiated and cured through a portion of the light transmitting body that transmits light in a straight line, scatters and transmits light incident from a predetermined angle, and transmits light incident from other angles in a straight line. . In other words, this cured film part gives an opaque view from a certain angle,
Other angles give a clear view. The linear light source has a long axis positioned substantially parallel to the surface of the film of the photopolymerizable composition, and is disposed in a space above the assembly.

The linear light source used in the present invention emits ultraviolet rays or other actinic rays that contribute to photopolymerization of the photopolymerizable composition of the film, and is irradiated at the irradiation position (film surface).
In view of this, the light source has a linear shape. 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 Those at most A / 10 or less are preferred.
A rod-shaped ultraviolet lamp is one of preferred linear irradiation light sources. A rod-shaped UV lamp (3KW) with a length of about 40cm and a diameter of about 2cm
For example, 40cm above a 10cm x 10cm film kept horizontal
When the lamp is arranged parallel to the film surface, the viewing angle A is about 54 ° and the viewing angle B is about 3 °. A rod-shaped ultraviolet lamp is a preferred linear light source in the present invention. In addition to such a linear light source, when viewed from the irradiated position,
A light source having an apparently linear shape, for example, a plurality of point light sources arranged in series, and an apparently linearly arranged light source or light from a laser beam or the like is scanned using a rotating mirror and a concave mirror (irradiation position). (A single point is irradiated from many different angles) can also be used as the linear light source.

When the irradiation light is ultraviolet, as a rod-shaped ultraviolet lamp,
For example, a mercury lamp or a metal halide lamp is suitable when easy handling is considered. Further, it is preferable that the length of the major axis of the linear light source is equal to or longer than the length of the film of the photopolymerizable composition.

In this case, as the length of the linear light source is increased, the light emitted from the linear light source is more likely to circulate behind the light scattering and transmitting pattern in the long axis direction of the linear light source. As a result, up to the film portion covered with the light-scattering transmission pattern is polymerized and cured, and the portion that should be transparent when viewed from any angle becomes a portion that provides an opaque visual field when viewed from an angle range. .

In order to avoid this inconvenience, the light irradiation by the linear light source is preferably performed by arranging a plurality of light baffles in a space between the linear light source and the assembly and passing through the light baffles. The plurality of light baffles are arranged substantially perpendicular to the surface of the assembly and at substantially equal intervals in the major axis direction of the linear light source, with each plate facing the plate surface.

That is, by irradiating light through the light baffle arranged as described above, light emitted from a position in the long axis direction of the linear light source, if the film portion at a position relatively far from the position If it reaches the film scattering portion, it is wrapped around after the light scattering / transmitting pattern, but it is cut by the light baffle plate and cannot reach the film portion. In other words, by irradiating light through the light baffle plate, light emitted from a position in the long axis direction of the linear light source can reach only the film portion immediately below and relatively near the film portion. Therefore, it does not go behind the light-scattering transparent pattern.

The light baffle used here may be any as long as it can block light that can be photocured, but a thinner one is more preferable.

On the other hand, when the light irradiating source is a point light source or a parallel light source, the cured film portion irradiated with light through a portion of the light transmitting body that scatters and transmits the irradiated light is such that incident light from any angle is transmitted straight. Thus, the cured film portion irradiated with light through the light straight transmitting portion of the light transmitting body scatters and transmits incident light from any angle.

According to the present invention, a light control plate having a light straight transmission area defined by the light scattering transmission pattern of the light transmission body is manufactured by the method as described above.

According to the present invention, there is further provided a method for continuously manufacturing a light control plate when the irradiation light source is a linear light source.

That is, such a continuous production method provided by the present invention comprises: (1) a method of producing a film of a photopolymerizable composition and a light transmitting body having a predetermined light scattering / transmitting pattern disposed along the surface of the film; Wherein the photopolymerizable composition comprises: (a) at least two monomers having a polymerizable carbon-carbon double bond and capable of producing a polymer having a different refractive index; A mixture, (b) at least one monomer having a plurality of polymerizable carbon-carbon double bonds in a molecule, and (c) a compound having no polymerizable carbon-carbon double bond and a polymerizable carbon-carbon double bond. A mixture of at least one monomer having a heavy bond and capable of forming a polymer having a refractive index different from the refractive index of the compound, and (2) continuously forming the assembly in a plane direction of the film. While moving to The assembly is irradiated with light at a limited angle from the side where the light transmitting body is present to polymerize the photopolymerizable composition of the film, wherein the light crosses the direction of movement of the assembly and the film. Is emitted from a linear light source arranged in the space above the assembly so that the major axis is positioned substantially parallel to the surface of the assembly, and thus only the incident light at a predetermined angle is scattered and transmitted, and the incident light at other angles goes straight. A method for continuously manufacturing a light control plate, comprising forming a light control plate having a region through which light is transmitted and a region through which incident light at any angle is transmitted straight.

In the above continuous production method (hereinafter referred to as a continuous method), step (1) is exactly the same as step (1) in the method described above.

According to the continuous method, in the step (2), that is, in the second step, the assembly is continuously moved in the plane direction of the film, and the assembly is limited from the side where the light transmitting body is present. Irradiate light. The light to be irradiated at this time is emitted from a linear light source arranged such that the major axis is located in a direction crossing the moving direction of the assembly.

By using a linear light source and irradiating the assembly with light at a limited angle from the side where the light transmitting body is present, a light straight transmitting portion corresponding to a portion other than the light scattering and transmitting pattern of the light transmitting body. Limited, the light control plate provided with a region that scatters only light at a specific angle, that is, anisotropy with respect to the major axis and minor axis direction of the linear light source, and rotated about the major axis direction of the light source Only when this is the case, a light control plate having a region that scatters light at a specific angle and a region that is transparent when viewed from all angles corresponding to the pattern is obtained.

That is, in the step (2), while moving the assembly, the light from the linear light source arranged so that the major axis is located in the direction crossing the moving direction is transmitted between the assembly and the linear light source, for example. The light is radiated through the light transmitting body to the moving assembly by cutting part of the light by the irradiation angle limiting means provided in (1), that is, cutting the light of the portion that falls on the upstream side in the moving direction of the assembly. In other words, in the step (2) of the present invention, the light is irradiated at a limited angle because only the light of the portion that falls downstream with respect to the moving direction of the assembly is irradiated to the assembly. Thus, according to step (2),
The assembly always receives light from the linear light source through the light transmitting body at a constant angle in the moving direction of the assembly. This makes it possible to produce a light control plate with a region where the angle of the scattered incident light is constant.

The irradiation angle limiting means is provided so that, for example, the moving assembly can be shielded from light irradiation in the moving direction.

The shape of the tip for limiting the light irradiation angle with respect to the assembly of the irradiation angle limiting means is preferably linear,
The straight tip may be perpendicular or inclined to the direction of movement of the assembly.

Further, it is desirable that the linear light source be provided such that the length of its major axis is equal to or greater than the length in the direction orthogonal to the moving direction of the assembly.

In this case, as the length of the linear light source increases, the light irradiation from the linear light source easily wraps around the light scattering and transmitting pattern in the long axis direction of the linear light source. It is preferable to provide such a light baffle.

<Effects and Effects> Hereinafter, light is irradiated from a linear light source through a light straight transmission area (area other than the light scattering transmission pattern) of the light transmitting body, and the cured film portion is incident light at a specific angle. Having a selective light scattering function of scattering and transmitting only light will be described with reference to the accompanying drawings.

Above an unpolymerized film placed horizontally, for example, about
The linear light source is disposed horizontally at a position inclined about 45 ° measured from a vertical surface set up from the center of the film surface at a height of 40 cm so that the length direction of the light source is parallel to the vertical surface and light is emitted. When the film is irradiated to cause a curing reaction of the film, the resulting cured film has anisotropy. That is, looking at the cross section of the cured film as shown in FIG. 9, a microstructure layer 9 is formed inside the cured film with the light irradiation surface side being 8. The thickness d2 of this layer is about 5-5000 microns and the depth d1 from the surface to the layer is 0-100 microns. The thickness of d1 changes depending on the atmosphere in which the curing reaction of the film occurs. Here, the thickness d3 of the layer is usually 25-5000μ.
m.

As shown in FIG. 10 which is a plan view and FIG. 9 which is a cross-sectional view, the microstructure layer 9 is composed of a number of elongated microscopic bodies 11 and 12 extending almost parallel to the linear light source 13. A- in FIG.
As shown in FIG. 7-a, which is a sectional view taken along the line A ', each of the microscopic bodies 11, 12 has an angle Z' smaller than the irradiation direction Z of the light from the irradiation source shown in FIG. 7-b. It is inclined. This angle Z 'is substantially equal to the refraction angle at which the irradiated light refracts in the film and travels. The pitch d5 between each minute body 11 and 12 is
0.1-20 μm.

The light selective scattering property of this film is such that in FIG. 8, light A1 incident at an angle Y1 equal to the irradiation angle Z from the irradiation source and light 1A incident at an angle Y2 equal to the irradiation angle Z on the opposite side of the film are: Most strongly scattered. In other words, when viewed from the other side through the film at that angle, the view becomes most clouded and the view is obstructed. The incident light is not necessarily the incident light parallel to the plane of FIG. 8, but also the light containing the light beam at the incident angle Y1 or Y2 and passing through a plane perpendicular to the plane of the paper and entering the film (projected onto the plane of the paper). The incident light equal to the measured incident angle Y1 or Y2) is scattered most strongly. The haze ratio with respect to light having various incident angles shows a mountain-shaped graph shape which is maximum near the Z incident angle. If the size of the illuminating light source becomes smaller and the viewing angle A of the major axis becomes smaller than 5 ° in terms of the aforementioned viewing angle, the film after polymerization no longer shows anisotropy, Even it becomes scattered. A film polymerized using a point light source or substantially parallel light as the irradiation light source will exhibit non-directional light scattering.

Conversely, when the size of the irradiation light source gradually increases, the height of the peak of the graph of the haze ratio decreases, and the size of the irradiation light source is represented by the viewing angle, and the viewing angle B in the short axis direction is larger than 100 °. When they do, they no longer show anisotropy. That is, the irradiated and polymerized film is transparent from any direction and does not exhibit selective light scattering.

Such a light source may be a surface light source located relatively close to the film to be polymerized, or a diffuse light source. Also, when the film is polymerized by heating, it becomes transparent.

It is not clear why the film polymerized using the linear light source shows selective light scattering in this way, but in FIG. 10, the microstructures 11 and 12 are layered structures having mutually different refractive indexes,
(Such a refractive index difference is closely related to a refractive index difference of a homopolymer of a monomer of a photopolymerizable compound used as a raw material of a film). This is considered to be because light is diffracted and scattered at boundaries between regions having different refractive indexes. The angle selectivity is determined by the angle selectivity of the diffraction and by the spacing of the layer structures. In other words, the smaller the layer spacing, the larger the scattering angle width. Further, the haze ratio indicating the degree of scattering is affected by the disorder of the layer structure. That is, the greater the disturbance, the higher the haze ratio. Further, if the same layer structure is disturbed, the thicker the film, the longer the distance through which light passes, so that the degree of scattering is amplified and the haze ratio is increased.

When the irradiation light source is a surface light source or a diffuse light source, such a microstructure is not formed, and the film is transparent and does not show selective light scattering. When the irradiation light source is a point light source, a microstructure is formed in the film, but it is arranged randomly without regularity as in the case of a linear light source. It is believed that the film reflects within the structure to provide non-directional light scattering.

<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 a polyether urethane acrylate (refractive index: 1.481) consisting of polypropylene glycol, hydroxyethyl acrylate and isophorone diisocyanate;
Tribromophenoxyethyl acrylate (refractive index 1.56
7) A polymerizable composition comprising 100 parts and 6 parts of hydroxyisobutylphenone was prepared. This composition is 40cm x 40cm
And pour it onto the glass substrate 1 with a thickness of 2 mm
A film was formed on a film 5 having a thickness of 0 cm and a thickness of 300 μm. While the third
As shown in the figure, the pattern of the font "A" was sandblasted to make the surface a rough surface in the form of a pickpocket.
Then, another mask glass plate (light transmitting body) 2 having a thickness of 2 mm was prepared. As shown in FIGS. 1 and 2, a spacer 1 having a height of 1 mm is arranged around a glass substrate 1 having a film 5 of a polymerizable composition as an upper surface, and the light transmitting body 2 is placed on a surface with a pick. It was held down on it. A rod-shaped ultraviolet lamp 3 (80 W / cm, 2 KW, diameter 2 cm, emission length 25 cm) spaced 50 cm vertically upward from the center of the glass substrate 1
Was set horizontally and parallel to the side ab of the glass substrate 1. Ultraviolet light was irradiated from the lamp 3 through the mask glass plate 2 to photo-cur the polymerizable composition of the film 5. The cured film was peeled from the glass substrate 1. A light control plate in the form of a film was obtained. When the light control plate was viewed from the front in the direction in which the lamp was installed, the portion of character A appeared transparent, and the other portions appeared opaque. When rotated more than 25 degrees left and right in the axial direction of the side ab, portions other than the characters appeared transparent, and the outline of the character A became completely invisible.

The total light transmittance and the scattered light transmittance of this light control plate were measured for the portion of character A and the portion other than character A, respectively, using an integrating sphere type light transmittance measuring device according to JISK-6714, and the haze ratio (cloudiness value) was measured. I asked. The haze ratio was calculated by tilting 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 to change the angle between the incident light and the light control plate. FIG. 4 shows a change in the haze ratio with respect to the incident angle.

Here, the solid line displayed as “character A” is the part of character A,
A solid line indicating “other than character A” indicates a haze ratio in a portion other than character A. That is, the absolute value of the haze ratio of the character A portion of the light control plate is 1% or less regardless of the incident angle, and the absolute value of the haze ratio of the incident light having an incident angle of 90 degrees in the portion other than the character A. Was about 75%.

Example 2 A light control plate was prepared under the same conditions as in Example 1 except that an ultra-high pressure mercury lamp (20 mm × 20 mm) in the form of a small sphere was used instead of the rod-shaped ultraviolet lamp in Example 1. In the obtained light control plate, the portion of the character A appeared transparent and the other portions appeared opaque from any angle.

Example 3 To 100 parts of polyether urethane acrylate (refractive index: 1.490) obtained by the reaction of polytetramethylene ether glycol having an average molecular weight of 2,000 with toluene diisocyanate and 2-hydroxyethyl acrylate, 100 parts of tribromophenoxyethyl acrylate and benzyl dimethyl were used. A polymerizable composition was prepared by adding and mixing 6 parts of ketal. This composition was poured on a glass substrate 1 of 40 cm × 40 cm and 2 mm in thickness, and formed into a film 5 of 25 cm × 40 cm and 300 μm in thickness. On the other hand, vertical line 2mm, horizontal line 5mm
A mask body glass plate 2 having a size of 40 cm × 40 cm and a thickness of 2 mm was prepared in which the surface other than the latticed portion was roughened in a sanded state by sandblasting. As shown in FIG. 5 and FIG. 6, a spacer 4 having a height of 2 mm is arranged around the glass substrate 1 with the polymerizable composition film 5 facing upward, and the mask body glass plate 2 is Was held down on it. 70 vertically upward from the center of the glass substrate 1
Stick-shaped UV lamp 3 (30W / cm, 2.1K
W, diameter 2 cm, emission length 70 cm) were set horizontally and parallel to the side ab of the glass substrate 1. 20cm × 20cm × whose surface is anodized perpendicular to the long axis direction of the lamp
Place the 3mm thick aluminum light baffle 7 at a position 15cm below the lamp.
Thirteen were arranged at cm intervals. Ultraviolet light was irradiated from the ultraviolet lamp 3 through the glass plate 2 of the mask body to photo-harden the polymerizable composition of the film 5. The cured film was peeled from the glass substrate 1 to obtain a film-shaped light control plate. Looking at this light control board from the front in the direction where the lamp was installed,
The plaid portions appeared opaque, and the other portions appeared transparent. The parts other than the plaid appeared transparent from any angle. When rotated more than 25 degrees to the left and right in the axial direction of the side ab, the plaid portions became transparent and the outline of the plaid patterns became completely invisible.

When the light control plate was viewed from the front in the direction in which the lamp was installed, the width of the vertical and horizontal lines of the opaque lattice was 2.05 mm, and the horizontal line was 5 mm. In addition,
The light control board created in the same manner as above except that the light baffle was removed has a vertical line width of opaque plaids and a horizontal line when viewed from the front in the direction in which the lamp was installed.
The horizontal line indicated 2.9 mm and the horizontal line indicated 5 mm.

Example 4 The same composition as in Example 1 was poured onto a glass substrate 21 having a size of 70 cm × 40 cm and a thickness of 2 mm to form a film 25 having a size of 70 cm × 25 cm and a thickness of 300 μm. On the other hand, as shown in FIG. 3, another mask body glass plate (light transmitting body) 22 having a size of 70 cm × 40 cm and a thickness of 2 mm prepared by sandblasting the pattern of the character “A” with a sand blast is prepared. I do. A spacer 1 having a height of 1 mm is arranged around the glass substrate 21 with the film 25 of the polymerizable composition on the upper surface, and the light transmitting body 22 is held on the surface with the slot on the lower side, and the assembly is assembled.
26 was prepared. As shown in FIG. 11, assembly 26
It was placed on a rotating roll 28 provided at intervals of 30 cm. The roll 28 rotates at a constant speed, and the traveling direction of the assembly 26 is
The assembly 26 was placed horizontally at a right angle to the ab direction (of FIG. 1), and the assembly 26 was moved (rightward in the drawing) at a speed of 40 cm / min. A rod-shaped UV lamp 23 (80W / cm 5.6k) is placed 70cm above the top of the assembly 26.
w, lamp diameter 2 cm, lamp length 70 cm) with its length direction horizontal and parallel to the axis of roll 28, ie assembly
26 were arranged so as to be parallel to the width direction (ab). Further, 13 light aluminum baffles 27 each having a surface of 20 cm × 20 cm and having an alumite treatment and having a thickness of 3 mm, which are perpendicular to the long axis of the lamp 23, were arranged at a position 15 cm below the rod-shaped ultraviolet lamp 23 at intervals of 5 cm. The irradiation angle limiting means 29 was disposed immediately above the upper surface of the assembly 26. The tip of the irradiation angle limiting means 29 is located in a vertical position from directly below the rod-shaped ultraviolet lamp 23 in the drawing and parallel to the roll axis. While the assembly 26 was moved by the rotation of the roll 28, the polymerizable composition of the film 25 was irradiated with ultraviolet light from the rod-shaped ultraviolet lamp 23 via the light transmitting body 22, and was light-cured. The cured film 25 was peeled off from the glass substrate 21 to obtain a film-shaped light control plate. When the light control plate was observed from the front, a transparent character "A" was seen in the cloudy surroundings. The shape and the size of the transparent character “A” correspond to the character “A” of the light transmitting body 22.
Was exactly the same. When the light control plate was tilted left and right about 20 degrees or more about the side ab, the entire light control plate became transparent and characters could not be seen.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a combination of an assembly comprising a polymerizable composition and a light transmitting body having a light scattering and transmitting pattern and a linear light source used in step (1) of the present invention. FIG. 2 is a side view of FIG. FIG. 3 shows an example of light transmittance having a light scattering transmittance pattern A used in the present invention. FIG. 4 shows the optical characteristics of the light control plate manufactured by the method of the present invention. FIG. 5 is a schematic perspective view for explaining the method of the present invention including a device having a light baffle for performing the method of the present invention. FIG. 6 is a schematic side view of the apparatus shown in FIG. FIGS. 7a, 7b, 8, 9, and 10 are explanatory views for explaining the principle of the present invention. FIG. 11 is a side view for explaining the method of the present invention including an apparatus having a light baffle for carrying out the present invention. DESCRIPTION OF SYMBOLS 1 ... Glass substrate, 2 ... Light transmitting body 3 ... Bar-shaped ultraviolet lamp, 4 ... Spacer 5 ... Resin composition film

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Satoshi Ishizuka 3-5-11 Doshomachi, Chuo-ku, Osaka City, Osaka Prefecture Inside Nippon Sheet Glass Co., Ltd. (72) Inventor Shinichiro Kitayama 6th Kitahara, Tsukuba City, Ibaraki Prefecture Sumitomo Chemical Co., Ltd. (72) Inventor Jiro Hozumi, 6th Kitahara, Tsukuba, Ibaraki Prefecture Sumitomo Chemical Co., Ltd. (72) Inventor Jiro Hozumi, 6th Kitahara, Tsukuba, Ibaraki Sumitomo Chemical Co., Ltd. (56) References JP Hei 1-40903 (JP, A) JP-A Hei 1-40946 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02B 5/00-5/136

Claims (5)

(57) [Claims] (1) A film of a photopolymerizable composition, and a light-transmitting member provided along a surface of the film and having a light-scattering / transmitting pattern for scattering and transmitting light and a portion for directly transmitting light. Preparing an assembly comprising: (a) at least two kinds of monomers having (a) a polymerizable carbon-carbon double bond and capable of producing polymers having different refractive indices; A mixture of (b) at least one monomer having a plurality of polymerizable carbon-carbon double bonds in the molecule, and (c) a compound having no polymerizable carbon-carbon double bond and a polymerizable carbon-carbon. A mixture of at least one monomer having a double bond and capable of forming a polymer having a refractive index different from that of the compound; and (2) adding the light transmitting member to the assembly. Located on the side that exists, [1] on A linear light source having a long axis positioned substantially parallel to the surface of the film of the photopolymerizable composition, or [2] light from a point light source or a parallel light source is irradiated to form a photopolymerizable composition of the film. (A) from the linear light source, defined by the light scattering transmission pattern, which allows the incident light at any angle to travel straight through; In the case of irradiating the light, only the area where the incident light of a predetermined angle is scattered and transmitted and the incident light of the other angle is directly transmitted, or when the light from the point light source or the parallel light source is irradiated, Forming a light control plate having a region that also scatters and transmits incident light having an angle of. 2. The light irradiation in the step (2) is performed from the linear light source, and the light irradiation is performed through a plurality of light baffles disposed in a space between the linear light source and the assembly. And the light baffles are arranged substantially perpendicular to the plane of the assembly and substantially equidistantly along the longitudinal axis of the linear light source, with each plate facing the plane of the patent. A method for manufacturing a light control plate according to claim 1. (1) From a film of a photopolymerizable composition and a light-transmitting body provided along a surface of the film and having a light-scattering / transmitting pattern for scattering and transmitting light and a portion for directly transmitting light. Wherein the photopolymerizable composition comprises: (a) at least two monomers having a polymerizable carbon-carbon double bond and capable of producing a polymer having a different refractive index; A mixture, (b) at least one monomer having a plurality of polymerizable carbon-carbon double bonds in a molecule, and (c) a compound having no polymerizable carbon-carbon double bond and a polymerizable carbon-carbon double bond. A mixture of at least one monomer having a bond and capable of producing a polymer having a refractive index different from the refractive index of the compound, (2) the assembly is continuously performed in the plane direction of the film. Move the above assembly On the other hand, light is irradiated at a limited angle from the side where the light transmitting body is present to polymerize the photopolymerizable composition of the film, wherein the light is directed in a direction transverse to the moving direction of the assembly and on the surface of the film. Is emitted from a linear light source disposed in the space above the assembly such that the major axis is located substantially parallel to the above, and thus only the incident light at a predetermined angle is scattered and transmitted, and the incident light at other angles is transmitted straight. A method for continuously manufacturing a light control plate, comprising: forming a light control plate having a region and a region for directly transmitting incident light at any angle. 4. The method according to claim 2, wherein the light in the step (2) is partially cut by an irradiation angle limiting means located between the assembly and the linear light source, and is applied to the assembly at a limited angle. 4. A method for continuously producing a light control plate according to claim 3. 5. The light irradiation in the step (2) is performed through a plurality of light baffles arranged in a space between the linear light source and the irradiation angle limiting means. 5. The linear light source according to claim 3, wherein the plates are arranged substantially perpendicular to the surface of the assembly and at substantially equal intervals in the major axis direction of the linear light source so that the plates face each other. 3. A method for continuously producing a light control plate according to claim 1.