JPH0267501A - Manufacture of light control plate - Google Patents

Abstract

PURPOSE:To eliminate the restriction to a light control plate which is constant in the incident angle of scattered rays of light by hardening a film-like body while the film-like body is irradiated with the light of a light source at a prescribed irradiating angle over the full length of the film-like body. CONSTITUTION:A photopolymerizing material containing at least two kinds of compounds having polymerizing carbon-carbon binding in molecules and different refractive indexes is held on a film-like body 4 having a specific length and width. On the other hand, a light source 1 is positioned against the film-like body 4 in such a way that the length direction is extended across the length direction of the film-like body and an irradiating angle limiting means 2 which causes each part of the film-like body in the width direction to be irradiated with the light of the light source 1 at prefixed angles is provided between the light source 1 and film-like body 4. Then the film-like body 4 is relatively moved against the light source 1 and limiting means 2 in the length direction so that the film-like body 4 can be irradiated with the light of the light source 1 at prescribed irradiating angles and hardened. Therefore, a light control plate which is constant in the incident angle of scattered rays of light can be obtained continuously.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing a light control plate that scatters only incident light from a specific angle.

(Conventional technology) Conventional transparent materials made of plastic or glass were only transparent to light from any angle.Therefore, as a material that only transmits light from a specific angle, a transparent sheet of plastic was used. A relief pattern such as a lattice or stripes is provided on a transparent substrate using an alignment film cut out from a plastic block made by alternately laminating opaque sheets or a photosensitive resin, and then a transparent substrate, etc. is combined on top of that. So-called ``shading plates'' were used for boat fishing.

As this light shielding plate, for example, there is one shown in Japanese Patent Laid-Open No. 189489/1989. However, these conventional alignment films and light shielding plates have problems in that they are expensive due to complicated manufacturing methods and that the film quality is not uniform.

Also, patent application No. 62-316460 (S 62.12
．． Photopolymerizable compositions consisting of compounds having one or more polymerizable carbon-carbon double bonds in molecules with different refractive indexes, as seen in Application No. 14) "Light control plate and method for producing the same" There is a light control board that is manufactured by irradiating an object with light from a specific direction and curing it. In this case, a rod-shaped lamp is used as the light source, and the cured resin plate exhibits anisotropy with respect to the long and short axes of the light source, and only when rotated around the long axis of the light source, the hardened resin plate exhibits anisotropy at a specific angle. scatters light.

That is, the produced resin plate has regions with different refractive indexes oriented in a certain direction, and it is thought that light incident from a specific angle is scattered by this structure.

<Problems to be Solved by the Invention> In the method for manufacturing the light control board described above, the direction of the short axis of the light source of the object to be irradiated, which is a photopolymerizable composition (hereinafter referred to as the longitudinal direction of the object to be irradiated) ) when the visual angle of the irradiated object is 20° or more when viewed from the light source, the angle of incidence of light on the irradiated object differs depending on the position in the length direction. In the light control plate, the angle of scattered incident light clearly differs depending on the position in the length direction. For example, even if a light control plate is manufactured so that vertically incident light is scattered, vertically incident light will be transmitted without being scattered in areas where the viewing angle is 20° or more when viewed from the light source. .

As described above, in the manufacturing direction of the light control plate, there is a problem in that the length of the light control plate in which the angle of the incident light to be scattered is constant is significantly limited. In other words, it is impossible to manufacture a large-area light control plate in which the angle of scattered incident light is constant.

Means for Solving the Problems> The present invention provides a method for manufacturing a light control plate in which the incident angle of scattered incident light is constant.

That is, the present invention provides a film-like composition having a predetermined length and width, in which a photopolymerizable composition containing at least two compounds each having a polymerizable carbon-carbon bond in the molecule and having mutually different refractive indexes is used. a linear light source is arranged opposite to the membrane-like body so that the long axis direction of the light source extends across the length direction; and a position in the width direction of the membrane-like body. irradiation angle limiting means for irradiating a part of the film-like body with light from the light source at a predetermined angle is disposed between the light source and the film-like body; the light source and the limiting means; curing the film-like body by irradiating the light from the light source at a predetermined irradiation angle over the entire length of the film-like body while moving the film-like body relative to the film-like body in its length direction. This is a method for manufacturing a light control plate that selectively scatters light incident at a specific angle of incidence.

The compound having a polymerizable carbon-carbon double bond used in the present invention is preferably one having an acryloyl group, a methacryloyl group, a vinyl group, or an allyl group in the molecule. Examples of this compound include 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, ethylcarpitol acrylate, dicyclopentenyloxyethyl acrylate, isobornyl acrylate, phenylcarpitol 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,
Vinyl compounds such as p-chlorostyrene, divinylbenzene, vinyl acetate, acrylonitrile, N-vinylpyrrolidone, vinylnaphthalene, or diethylene glycol bisallyl carbonate, diarylidene pentaerythritol, triallylisocyanurate, diallyl phthalate, diallyl isophthalate, etc. Examples include allyl compounds.

These compounds can also be used as monomers or oligomers.

In the present invention, at least two selected from these compounds
Although the species are used as a mixture, their homopolymers must have different refractive indices; the greater the difference in their refractive indexes, the higher the haze of the resulting resin. Preferably, the at least two compounds have a refractive index difference of at least 0.01, more preferably at least 0.05. When three or more kinds of compounds are used, it is sufficient that the difference in refractive index of any two of their homopolymers satisfies the above conditions. The mixing ratio of the two compounds having a refractive index difference of at least 0.01 is preferably in the range of 10:90 to 90:10 by weight. Further, it is preferable that the compatibility of these resins is low to some extent. 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 too low, phase separation will occur before photocuring, and the resulting resin will have an excessively high haze rate, resulting in haze over the entire surface, and will not exhibit any light control function.

In the present invention, the light control resin plate maintains a photopolymerizable composition containing a mixture of the above compounds and a photopolymerization initiator as necessary in a film form, and irradiates it with light from a linear light source, preferably ultraviolet light. It can be obtained by The photopolymerization initiator used here is not particularly limited, and any initiator used in normal photopolymerization may be used.

Examples include benzophenone, benzyl, Michler's ketone, 2-chlorothioxanthone, benzoin ethyl ether, jetoxyacetophenone, benzyl dimethyl ketal, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexylphenyl ketone, etc. .

In the present invention, the photopolymerizable composition is applied onto a substrate, or the photopolymerizable composition is placed in a cell in which two plate-shaped bodies transparent to irradiation light for photopolymerization are provided at a predetermined interval. The membranous body is maintained by encapsulating things.

The term "membrane-like material" in the present invention refers to a material having a relatively large surface area compared to its thickness, and is defined as including a sheet-like material.

This film-like body usually has a thickness of 25 μm to 1000 μm, and a thickness of 20 μm.
Width of C11~200C111 and 20Crn~several hundred meters
It has a length of

In the present invention, the film thickness of the photopolymerizable composition coated on the substrate or sealed in the cell must be thick to some extent, at least 25 μm, and the preferred film thickness is 100 μm. , more preferably 200 μm or more. That is, according to the present invention, a layer having a special structure that scatters only incident light from a specific direction is formed inside a film-like body cured by ultraviolet irradiation. This layer is considered to have a structure in which microstructures with different refractive indexes are arranged in parallel in a specific direction. If the film thickness of the photopolymerizable composition is too small, the formation of this microstructured layer is hindered. As this film thickness increases, the thickness of the microstructure layer also increases, which is preferable because the light scattering performance (haze rate) increases.

The linear light source used in the present invention emits ultraviolet rays and other light that contributes to photopolymerization of the photopolymerizable composition of the film-like body, and when viewed from the irradiated position (the surface of the film-like body). 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 degrees, preferably at least 12 degrees, and the viewing angle B in the short axis direction of the light source is at most A/4, more preferably. is preferably at most A/10. A rod-shaped UV lamp is one of the preferred linear radiation sources. A rod-shaped ultraviolet lamp (3
For example, when KW) is placed 40 cm above a 10 cm x 10 cm membrane part kept horizontally so that the lamp is parallel to the membrane surface, the viewing angle A is approximately 54°, and the viewing angle B
is approximately 3°, which is a suitable linear light source in the present invention. In addition to such a linear light source, when viewed from the irradiated position,
The light source appears to be linear, for example, a number of point light sources are arranged in a line, or the light from a laser beam is scanned using a rotating mirror and a concave mirror. A device that irradiates one point from multiple different angles can also be used as a linear light source.

When the irradiation light is ultraviolet rays, the rod-shaped ultraviolet lamp is not particularly limited as long as it emits ultraviolet rays, but a mercury lamp or a metal halide lamp is usually suitable in consideration of ease of handling.

When a linear light source is used and the irradiation conditions are adjusted, the resulting sheet-like cured material exhibits anisotropy in the long and short axis directions of the light source, and when rotated around the long axis of the light source, It only scatters light at a specific angle.

Here, the light control plate having a selective light scattering function will be described in detail.

Above the film-like body of the photopolymerizable composition placed horizontally,
For example, place the linear light source at a position approximately 401 above and inclined at Z = approximately 45 degrees as measured from a vertical plane erected from the center of the film surface, so that the length direction of the light source is parallel to the vertical plane and horizontally. When placed and irradiated with light to cause a curing reaction of the film, anisotropy occurs in the created film. That is, the 12th
As shown in the figure, when looking at the cross section of the membrane, a microstructured layer 23 is formed inside. The thickness d2 of this layer is approximately 25-500
0μI, and the layer depth dl from the surface is 0-100μ
It is m.

The thickness of dl varies depending on the atmosphere in which the film hardening reaction occurs.

Here, the thickness d3 of the film is usually 25 to 5000 μm. As shown in FIG. 13, which is a plan view, and FIG. 14, which is a side view, the microstructure layer 23 is composed of a large number of elongated microbodies 24 extending in a direction parallel to the linear irradiation source 25. As shown in FIG. 15, which is a cross-sectional view taken along line A-A in FIG. 13, each of the microscopic bodies 24 is inclined by an angle Z' smaller than the direction Z of light irradiation from the irradiation source. be observed.

This angle Z' is approximately equal to the refraction angle at which the irradiated light is refracted and travels within the film. The pitch d5 of each microbody 24 is 0.1
~20 μm. The light selective scattering property of this film is shown in Fig. 16, where the light incident from the irradiation source at an angle Yl equal to the irradiation angle Z, and the light incident on the opposite side of the film at an angle Y2 equal to the irradiation angle Z are the strongest. Scattered. In other words, when you look at the other side through the membrane at that angle, it becomes cloudy and obstructs your vision. The incident light is not necessarily parallel to the plane of the paper in FIG. 16, but also at the incident angle Y1 or Y2.
Light that enters the film through a plane perpendicular to the plane of the paper (the angle of incidence measured by projecting it onto the plane of the paper is Yl or Y2)
Incident light equal to ) is also most strongly scattered. The haze ratio for light at various incident angles is as shown in Figure 17.
It shows a chevron-shaped graph shape that is maximum near the incident angle of Z.

If the size of the irradiation light source becomes small and the viewing angle A in the long axis direction becomes 5 degrees, the film after polymerization will no longer exhibit anisotropy, and no matter which direction of incidence It also scatters light. A film polymerized using a point light source or substantially parallel light as the irradiation light source exhibits nondirectional light scattering.

Conversely, as the size of the irradiation light source gradually increases, the height of the peak on the haze rate graph decreases, and the size of the irradiation light source is expressed by the viewing angle, and the viewing angle B in the short axis direction becomes larger than 100°. When this happens, it no longer exhibits anisotropy.

That is, the irradiated and polymerized film is transparent when viewed from any direction and exhibits no selective light scattering.

Although the reason why a film polymerized using a linear irradiation source exhibits selective light scattering properties is not clear, it can be estimated as follows. In FIG. 15, the microscopic bodies 24 and the substance 26 between them probably have different refractive indexes (this different refractive index is due to the homopolymer of the photopolymerizable compound used as the raw material for the film). It is thought that this is closely related to the difference in refractive index), and light that enters the film at an angle close to the inclination angle Z' of the microscopic body is diffracted at the boundaries of regions with different refractive indexes, resulting in scattered light. .

If the irradiation light source is an area light source or a diffused light source, such microstructures will not be formed and the film will be transparent and exhibit no selective light scattering. In addition, when the irradiation light source is a point light source, although microstructures are formed within the film, they are not as regular as in the case of a linear irradiation source and are arranged randomly, so it is difficult to determine what kind of incident light It is thought that the film may also provide non-directional light scattering.

In the present invention, the linear light source is preferably arranged so that the long axis direction of the light source is perpendicular to the length direction of the film-like body so that the long axis direction of the light source extends across the length direction of the film-like body. Moreover, it is arranged so as to be parallel to the surface of the membrane-like body.

The membranous body is described as having a length and a width to facilitate explanation of anisotropy when it has a light control function. The membranous body may have a length shorter than its width.

An irradiation angle limiting means for irradiating a part of the film-like body with light from the light source at an angle predetermined according to a position in the width direction of the film-like body is disposed between the light source and the film-like body. do. As a means for limiting the irradiation angle, if all 11 parts of the membrane-like body are to be irradiated with light at an angle like -, the tip edge extends in the middle direction of the membrane-like body and the main body extends in the upward direction of the progression of the membrane-like body. For example, a light shielding plate provided as shown in FIG.

In the present invention, the light source and the limiting means are irradiated with light from the light source while the film-like body is placed on, for example, a conveyor and moved in its length direction. The part of the film-like body that passes under the light shielding plate and emerges from its leading edge is irradiated with light at a predetermined angle determined from the position of the light source and the leading edge, and is cured. When the light source position is fixed, the light irradiation angle can be controlled by adjusting the position (or shape) of the tip edge of the light shielding plate, so that it remains constant along the length of the membrane. The irradiation angle is obtained. Therefore, the cured film can have a constant light incidence angle along its length for selective light scattering.

Instead of fixing the light source and the limiting means and moving the film-like body, the film-like member may be fixed and the light source and the limiting means can be moved. However, the former method is convenient for irradiating a long strip-like film-like body.

In order to limit the irradiation angle, it is preferable that the light shielding member, which can limit the irradiation angle, be placed as close to the membrane as possible. A light shielding body having a slit opening in the width direction of the film-like body can also be used as the irradiation angle limiting means. In this case, an appropriate value for the slit size can be determined depending on the polymerization rate of the polymerization composition used, the relative movement speed of the film-like body, the light illuminance, etc.

<Effects of the Invention> According to the method of manufacturing a light control plate of the present invention, a light control plate having a constant incident angle of scattered incident light can be produced without being limited by the length of the light control plate to be manufactured. Can be manufactured continuously. That is, it is possible to manufacture a large-area light control plate as required. In addition, since it is possible to impart a constant scattering incident angle along the length of a continuous strip-shaped film, it is possible to cut this strip-shaped film with selective scattering function into desired dimensions to emit light. The control board can be assembled.

<Examples> The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 N-vinylpyrrolidone (refractive index 1.509) was added to 100 parts of polyether urethane acrylate (refractive index 1.481) obtained by the reaction of polypropylene glycol with an average molecular weight of 2000, toluene diisocyanate, and 2-hydroxyethyl acrylate. A polymerizable composition prepared by adding and mixing 100 parts of benzyl dimethyl ketal and 6 parts of benzyl dimethyl ketal was injected between two glass plates with a length of 500 m and a width of 300 mm with a spacer of 0.5 mm thick between them.
A film-like body of the polymerizable composition with a thickness of 0 μm is formed. As shown in FIGS. 1 and 2, the glass plate 4 is placed horizontally on the conveyor 3 so that its traveling direction is parallel to the length direction (AB) of the glass plate. move with speed. A rod-shaped ultraviolet lamp 1 (80W/am, 2kW) is installed above the conveyor at a height of 400 m above the conveyor surface.
, a lamp diameter of 2 cta, and a lamp length of 25 cn) are arranged so that their length directions are horizontal and perpendicular to the conveyor traveling direction. A light shielding plate 2 is placed immediately above the glass plate 4 on the conveyor.

The tip 5 of the light shielding plate 2 is located at an angle of α=10° from directly below the ultraviolet lamp in the direction toward the bottom of the conveyor movement, so as to be perpendicular to the conveyor movement direction. extending in the direction.

By irradiating the glass plate 4 with light from an ultraviolet lamp while moving it on the conveyor 3, the film of the polymerizable composition in the glass plate 4 is polymerized and hardened, and a light control plate is obtained.

The total light transmittance and scattered light transmittance of each part of the light control plate were measured using an integrating sphere type light fa transmittance measuring device in accordance with JISK-6714, and the haze rate (haze value) was determined.

The above values were calculated by tilting the light control plate around an axis parallel to its side BC and allowing light to enter from a direction perpendicular to the side BC while changing the angle between the incident light and the light control plate. FIG. 3 shows the dependence of the haze rate on the angle of incident light.

In the figure, the angle of incident light on the horizontal axis is 0° for light parallel to the surface of the light control plate from the BC side of the light control plate, and S for the surface of the light control plate.
Incident light perpendicular to the direction is expressed as 90°. 8
The haze rate for light incident at an angle of 0° is the highest. No matter which part of the light control plate was measured, the haze rate curve shown in FIG. 3 did not change. Figure 4 shows the position dependence of the haze rate in the length direction of the light control plate when the position of the incident light is changed in the length direction of the light control plate while maintaining the above 80” angle. It can be seen from FIG. 4 that when light is incident on the light control plate at an angle of 80°, the distortion ratio is constant along the length of the light control plate.

Example 2 Average molecule! 100 parts of tribromophenoxyethyl acrylate per 100 parts of polyether urethane acrylate (refractive index 1.490) obtained by the reaction of 2000% polytetramethylene ether glycol with toluene diisocyanate and 2-hydroxyethyl acrylate.
A resin composition prepared by adding and mixing 6 parts of benzyl dimethyl ketal and 6 parts of benzyl dimethyl ketal is poured onto a glass plate 500 m long and 300 m wide to form a film with a thickness of 300 μm.

As shown in FIG. 5, a light shielding plate having a slit opening with a width of 100 mm extending perpendicular to the conveyor traveling direction is placed directly under the ultraviolet lamp, and the same as in Example 1 is used except that the glass plate 7 is used. A light control plate is obtained by irradiating in the same manner. The incident angle dependence of the haze rate of this light control plate and the position dependence of the haze rate in the length direction of the light control plate = (
Incidence of light at an angle of 90'' (angle of incidence = 0°) is shown in FIGS. 6 and 7, respectively.

It can be seen from FIG. 7 that a large-area light control plate with a -like haze ratio was obtained.

Example 3 Bisphenol A type epoxy acrylate (refractive index 1.
560) 100 parts of 2.2.3.3-tetrafluoropropyl acrylate (refractive index 1.363
) and 6 parts of benzyl dimethyl ketal were added and mixed and cured in the same manner as in Example 2 to obtain a light control plate. FIG. 8 shows the position dependence of the haze rate when the incident angle of the manufactured light control plate is 0° (incident at an angle of 90°).

It can be seen from FIG. 8 that a large-area light control plate with a -like haze ratio was obtained.

Comparative Example 1 The same polymerizable composition as in Example 1 was injected between glass plates with a 0.5 mm thick spacer interposed therebetween to form an irradiated object with a width of 300 mm and a length of 500 mm.

As shown in Figure 9, side AB is 1 with respect to the horizontal plane.
Fix it so that it has an angle of 0°, and fix it horizontally with a mercury lamp at a position 400 ml directly above the center in the length direction so that the length direction is perpendicular to side AB, and irradiate it to cure it. . The incident angle dependence and position dependence (incident angle 0°) of the haze factor of the manufactured light control plate are shown in FIG. 10 and FIG. 11, respectively. In Figure 1O, P, Q,
R indicates the light incident position to the light control board as P and P in Figure 11, respectively.
Q.

Corresponding to R, the haze ratios are shown in the immediate vicinity of side BC, in the center, and in the immediate vicinity of side AD.

[Brief explanation of the drawing]

1 and 2 are a side view and a perspective view, respectively, showing one embodiment of the present invention, and FIGS. 3 and 4 are graphs showing the light scattering characteristics of a light control plate manufactured according to this embodiment. FIG. 5 is a side view showing another embodiment of the present invention, and FIG.
7 and 7 are graphs showing the light scattering characteristics of the light control plate manufactured according to this example, FIG. 8 is a graph showing the light scattering characteristics of the light control plate manufactured according to another example of the present invention, and FIG. The figures are side views showing comparative examples, Figures 10 and 11.
The figure is a graph showing the light scattering characteristics of the light control plate manufactured according to this comparative example, and FIGS. 12 to 16 are schematic diagrams for understanding the principle of the present invention. 1... Linear light source, 2, 6... Irradiation angle limiting means, 3
...Conveyor, 4.7...Membrane formation

Claims (1)

[Claims] Maintaining a photopolymerizable composition containing at least two compounds each having a polymerizable carbon-carbon bond in the molecule and having mutually different refractive indices in a film-like body having a predetermined length and width. , a linear light source is arranged opposite to the film-like body so that the long axis direction of the light source extends across the length direction, and an angle predetermined by the position in the width direction of the film-like body. and irradiation angle limiting means for irradiating a part of the film-like body with light from the light source is disposed between the light source and the film-like body, and irradiating the light source from the light source at a predetermined irradiation angle over the entire length of the film-like body while moving the film-like body relatively in its length direction at a specific incident angle, the method comprising: curing the film-like body; A method for manufacturing a light control plate that selectively scatters incident light.