JPH07333428A - Scattering type polarizing sheet and its production - Google Patents

Abstract

PURPOSE:To provide a scattering type polarizing sheet at a low production cost by a simple method and to provide its production method. CONSTITUTION:Calcite is cut along the cleavage into a planar calcite 12D. The surfaces 12A and 12B are roughly processed to obtain a calcite layer 12C. This calcite layer is embedded in such a resin 18 in a molten state that the refractive index in a solid state is substantially same or extremely near to one of two refractive indices of calcite. Then the resin is solidified to obtain a scattering type polarizing sheet 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing element, and more particularly to a scattering type polarizing sheet and a manufacturing method thereof.

[0002]

2. Description of the Related Art It is known to control the polarization to reduce the glare of light from a light source and to make the amount of diffusion variable. Generally, a polarizing film containing a dichroic dye is used for such purpose. In the case of such a polarizing film, since one polarized light is absorbed, the amount of emitted light is halved. A scattering type polarizing sheet has been proposed as a solution to this problem.

The proposed scattering-type polarizing sheet is composed of so-called birefringent substance, dust glass, which has a refractive index of 1.585 and 1.337, and two glass plates having a refractive index of 1.585.

[0004]

However, in the proposed scattering type polarizing sheet, two glass plates are arranged in parallel at a constant interval so that the roughened surfaces face each other, and within this interval, It could only be produced by growing a single crystal of chilli glass. According to this manufacturing method, it takes 2-3 days to grow a single crystal, so that the manufacturing cost is high and it is not practical. Therefore, the present invention can be manufactured in a simple manner,
An object of the present invention is to provide a scattering type polarizing sheet having a low manufacturing cost and a manufacturing method thereof.

[0005]

In order to achieve the above object, in the present invention, calcite is used in place of chili salt and synthetic resin is used in place of glass.

That is, according to the present invention, a flat plate element made of a birefringent material having two refractive indices n1 and n2, and the front and back surfaces of the flat plate element are substantially equal to the refractive index n1, respectively, Alternatively, in a scattering-type polarizing sheet in which optical elements having extremely close refractive indexes are laminated, calcite is used as the flat plate-like element, and synthetic resin is used as the optical element.

In order to manufacture the scattering type polarizing sheet having such a structure, the surface and the back surface of calcite disintegrated into a flat plate are roughened, and then embedded in a melt or semi-solid of PMMA resin.

Therefore, according to the present invention, a calcite is cleaved into a flat plate shape, the front and back surfaces of the calcite are roughened, and the calcite after roughening is a molten or semi-solid resin, There is provided a method of making a scattering-type polarizing sheet, which comprises steps of embedding in a solid state refractive index thereof substantially the same as or very close to one of the two refractive indices of the calcite.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a preferred embodiment of the scattering type polarizing sheet of the present invention. The scattering type polarizing sheet 10 has a three-layer structure of a first layer of PMMA (polymethylmethacrylate) resin layer 14, a second layer (intermediate layer) of calcite layer 12C and a third layer of PMMA resin layer 16. . The calcite layer 12C has a flat plate shape, and its front surface 12A and back surface 1 are parallel to each other.
2B is roughened and subjected to so-called roughening.

The calcite layer 12C is obtained by cleaving a suitable calcite, and the calcite is a birefringent substance as is well known. That is, calcite has n1 = 1.
It has two refractive indices of 487 and n2 = 1.660. On the other hand, the PMMA resin of the first layer and the third layer has, for example, n = 1.4.
92, which is very close to n1 = 1.487 is used. Since the refractive index of this PMMA resin can be made variable by copolymerization, it is possible to set n≈n1.

Next, a method of manufacturing the scattering type polarizing sheet 10 of the present invention shown in FIG. 1 will be described with reference to FIG. FIG. 2A shows a state in which calcite is disintegrated into a flat plate-shaped object 12D. Next, as shown in FIG. 2b, the parallel front surface 12A and back surface 12B of the flat plate calcite 12D are roughened to obtain a calcite layer 12C. Next, as shown in FIG. 2c, the calcite layer 12C is inserted into the bath 20 containing the melt 18 of PMMA resin in the direction indicated by the arrow. After the PMMA resin has solidified, the state taken out from the bath 20 is shown in FIG.
Is. That is, the solidified PMMA resin 18A is cut to obtain the scattering type polarizing sheet 10 having a desired size and shape as shown in e of FIG.

In this way, the roughened calcite layer 12C
Embedded in a molten resin or a semi-solid resin, the scattering type polarizing sheet of the present invention can be easily manufactured. Alternatively, a scattering type polarizing sheet can be obtained by inserting roughened calcite between two acrylic resin plates and polymerizing and adhering them with methyl methacrylate to which a photopolymerization initiator is added in these gaps. be able to.

[0013]

As described above, according to the scattering type polarizing sheet of the present invention and the manufacturing method thereof, since calcite and synthetic resin are used, a polarizing sheet with less loss of light quantity can be manufactured by a simple method. Because it can and is low cost
Suitable for industrial production.

[Brief description of drawings]

FIG. 1 is a sectional view showing a preferred embodiment of a scattering type polarizing sheet of the present invention.

FIG. 2 is a schematic view showing an example of a procedure of a method for manufacturing a scattering type polarizing sheet of the present invention.

[Explanation of symbols]

 10 Scattering type polarizing sheet 12A Front surface 12B Rear surface 12C Calcite layer 12D Flat calcite 14, 16 PMMA resin layer 18 Molten resin 18A Solidified resin 20 Bath

Claims (2)

[Claims] 1. A flat plate element made of a birefringent material having two refractive indexes n1 and n2, and refraction substantially equal to or extremely close to the refractive index n1 on the front surface and the back surface of the flat plate element, respectively. In a scattering type polarizing sheet in which optical elements having a refractive index are laminated, calcite is used as the flat element, and synthetic resin is used as the optical element. 2. A calcite is flattened into a flat plate shape, the front and back surfaces of the calcite are roughened, and the calcite after roughening is a molten or semi-solid resin in a solid state. Has a refractive index of 2
A method of manufacturing a scattering-type polarizing sheet, which comprises the steps of embedding in one that is substantially the same as or extremely close to one of the two refractive indexes.