JPH04323632A - Production of flyeye lens sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fly's eye lens sheet that can be used as a transmission screen for projection television.

0002

2. Description of the Related Art Conventional transmission screens use so-called lenticular lens sheets in which a large number of semicylindrical unit lenses are arranged in parallel to enhance the diffusion effect of transmitted light. This lenticular lens sheet was manufactured by extruding molten acrylic resin or the like from above a mold roll to form a lenticular lens.

However, the above-mentioned lenticular lens sheet has a disadvantage in that since the unit lenses are semicylindrical, it is easy to obtain a diffusion effect in the horizontal direction, but it is difficult to obtain a diffusion effect in the vertical direction. For this reason, conventionally, in order to obtain a diffusion effect in the vertical direction, it was necessary to mix a diffusing agent or to use a combination of lenticular lens sheets in which the running directions of unit lenses are orthogonal to each other.

[0004] Therefore, in order to provide a light diffusion effect in both the vertical and horizontal directions, it is conceivable to make the unit lens shape like a fly's eye. This fly's eye lens sheet has the same diffusion effect in the left and right directions as before, as well as a sufficient diffusion effect in the vertical direction. A wide range of gain can be obtained up to the height position.

[0005]Furthermore, the fly's eye lens sheet has a large proportion of the light emitting surface where light is not focused, about 7% compared to about 45% to 50% for conventional lenticular lenses.
It can be 0 to 75%, and by using this portion as a light absorption layer, there are advantages such as a transmission type screen with high contrast can be obtained.

[0006]

[Problems to be Solved by the Invention] However, since the unit lenses of the fly's eye lens sheet are arranged in a fly's eye (matrix) shape, it is difficult to manufacture a mold, and the moldability of the acrylic resin is difficult. It has been difficult to apply the conventional method for producing a lenticular lens sheet as described above due to problems such as poor quality and shrinkage of acrylic resin.

An object of the present invention is to solve the above-mentioned problems and provide a simple and efficient method for manufacturing a fly's eye lens sheet.

[0008]

[Means for Solving the Problems] In order to solve the above problems, a method for manufacturing a fly's eye lens sheet according to the present invention includes an ionizing radiation curing method in which a base material transparent to ionizing radiation is hardened by irradiation with ionizing radiation. a coating step in which the resin is applied almost uniformly; an embossing step in which a mold plate with holes in a fly's eye shape is pressed onto the ionizing radiation-cured resin to form a lens shape; and a step in which the ionizing radiation-cured resin is ionized. The structure includes a curing step of curing by irradiating with radiation.

[0009]

According to the present invention, a lens shape can be obtained by pressing a template with holes against an ionizing radiation-cured resin.

0010

EXAMPLES The present invention will be described in detail below with reference to the drawings and the like. FIG. 1 is a process diagram showing an embodiment of the method for manufacturing a fly's eye lens sheet according to the present invention. The manufacturing method of this example includes a coating step 101, an embossing step 102, and a curing step 103.

[0011] The coating step 101 is a step in which an ionizing radiation-curable resin 2, which is cured by irradiation with ionizing radiation, is applied substantially uniformly onto a base material 1 that is transparent to ionizing radiation. Base material 1
For example, a plastic plate that is transparent and transmits ionizing radiation such as ultraviolet rays (UV) and electron beams (EB), such as a resin sheet made of acrylic, polyester, polycarbonate, vinyl chloride, etc., can be used.

The ionizing radiation-curable resin 2 is a resin that is cured by ionizing radiation, and includes polymerizable oligomers and monomers having acryloyl groups such as urethane acrylate, epoxy acrylate, polyester acrylate, polyether acrylate, and melamine acrylate, and acrylic. Acid, acrylonitrile, a polymerizable oligomer or monomer having a polymerizable vinyl group such as styrene may be used alone or in combination, and if necessary, additives such as a sensitizer may be added.

The ionizing radiation-curable resin 2 has a diameter of 1/4 to 1/4 of the diameter of a fly's eye-shaped hole 3a made in a template 3, which will be described later, by a screen method, a roll coating method, a curtain coating method, a gravure method, or the like. It is preferable to apply the coating to a thickness of about 1/10.

The embossing step 102 is a step in which a template 3 with holes 3a in a fly's eye shape is pressed onto the ionizing radiation-cured resin 2 to form a lens shape. The template 3 can be produced by etching a fly's-eye (matrix) pattern on a metal plate such as iron or aluminum using a technique such as photolithography, or by mechanically punching. In addition, the material is not limited to a metal plate, and a highly rigid resin plate may be mechanically punched or cast-molded.

In order to control the lens shape, the ionizing radiation curing resin 2 is mixed with a monomer to lower its viscosity, or the temperature is raised to lower the viscosity, thereby making the lens shape gentler and reducing the diffusion angle. can do. Furthermore, by adjusting the coating thickness of the ionizing radiation curing resin 2, the amount of resin extruded from the holes 3a of the template 3 can be increased or decreased. A lens shape with a small radius can be obtained. Furthermore, by increasing the diameter of the hole 3a of the template 3, the radius of curvature can be increased. By adjusting the pressure with which the template 3 is pressed, the lens shape can be adjusted in relation to the film thickness.

In the curing step 103, the ionizing radiation curing resin 2
This is a step of irradiating the material with ionizing radiation 4 to harden it. At this time, since the ionizing radiation-curable resin 2 may be inhibited from curing by oxygen in the atmosphere during radical polymerization, it is preferable to irradiate the ionizing radiation in a nitrogen atmosphere.

Next, a more detailed explanation will be given by giving specific manufacturing examples. An acrylic resin plate with a refractive index of 1.49 and a thickness of 0.2 mm is used as the substrate 1, and a urethane acrylate-based ultraviolet curable resin is used as the ionizing radiation curable resin 2 on the entire surface of the substrate 1, and approximately It was applied uniformly to a thickness of 0.3 mm (see Figure 2).

On top of the ionizing radiation curing resin 2, a 0.2 mm thick iron plate with circular holes 2.0 mm in diameter made at 2.0 mm intervals and colored black on the surface was placed as a template 3 ( (see Figure 4), mold the lens shape by slowly applying pressure until the distance between the substrate 1 and the template 3 is approximately 0.15 mm,
The ionizing radiation curing resin 2 was cured by irradiating electron ultraviolet rays as ionizing radiation 4 in a nitrogen atmosphere (see FIG. 3).

The obtained fly's eye lens sheet has a uniform fly's eye lens, and the proportion of the light emitting surface where light is not focused is approximately 75 to 80% (conventionally, it was approximately 40 to 45%). ) and grew larger. In addition, since the template 3 was made of an etched iron plate, the surface of the template 3 has minute irregularities, which prevent light from the outside on the light-emitting surface and stray light on the internal surface. A screen with high scattering and high contrast was obtained.

The present invention is not limited to the embodiments described above, and various modifications can be made. As the template 3, a black plastic sheet may be used. In this case, there is an advantage that a material having a coefficient of thermal expansion closer to that of the ultraviolet curing resin used to form the lens shape can be used than a metal plate.

[0021]

As described above in detail, according to the present invention, a fly's eye lens sheet can be efficiently manufactured through simple steps. In addition, by using a colored template, the remaining template can be used as a light-absorbing layer, so there is no need for the conventional process of forming a light-absorbing layer on the non-light-emitting part of the light-emitting surface by printing, etc. This further simplifies the manufacturing process.

[0022] The fly's eye lens sheet obtained has a template made of metal or the like left, so it has greater tensile and bending strength than conventional thin lens sheets made only of resin, and is resistant to heat and heat. It is also less affected by changes in humidity.

[Brief explanation of drawings]

FIG. 1 is a process diagram showing an embodiment of a method for manufacturing a fly's eye lens sheet according to the present invention.

FIG. 2 is a cross-sectional view schematically showing the state after the coating process of this example.

FIG. 3 is a cross-sectional view schematically showing the state after embossing and curing of this example.

FIG. 4 is a plan view schematically showing the state after embossing and curing of this example.

[Explanation of symbols]

1 Board 2 Ionizing radiation curing resin 3 Template 3a hole 4 Ionizing radiation

Claims (1)

[Claims] 1. A coating step of substantially uniformly applying an ionizing radiation-curable resin that is cured by irradiation with ionizing radiation onto a base material that is transparent to ionizing radiation, and forming holes in a fly's-eye shape from above the ionizing radiation-curable resin. A method for manufacturing a fly's-eye lens sheet, comprising: an embossing step of pressing an open template to form a lens shape; and a curing step of curing the ionizing radiation-cured resin by irradiating it with ionizing radiation.