JP3235891B2 - Reflective screen - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type screen mainly used in an image system having a liquid crystal display.

[0002]

2. Description of the Related Art In a liquid crystal display device, a non-polarizing light source is converted into linearly polarized light by using a light absorbing polarizing filter. The use efficiency of the light from the light source is low due to the fact that the aperture ratio of the liquid crystal panel is low due to the existence of the light. Therefore, in an image system including a liquid crystal display device, when an image is projected on a large screen, the luminance is insufficient, and it is necessary to view the image in a dark room where external light is blocked. Focusing on the fact that the projected light emitted from the liquid crystal display device is linearly polarized light, whereas the external light that impairs the sharpness of the image projected on the screen is usually unpolarized light, There is known a technique for clearly viewing a projected image even in a bright environment by removing only the image. For example, a technology is known in which a light absorption type polarizing filter oriented in a direction of transmitting linearly polarized projection light is mounted on the surface of a screen, thereby reducing the amount of reflection of non-polarized external light. Kaisho 62-266980
And JP-A-64-77085). As the above-mentioned polarizing filter, a polarizing film obtained by adding iodine clusters to polyvinyl alcohol and orienting the same is well known. Instead of the polarizing film, a single fiber having a polarizing property as shown in FIG. Hereinafter, a polarizing cloth including a polarizing single fiber) and a transparent single fiber having no polarizing property (hereinafter, referred to as a non-polarizing transparent single fiber) can also be used.

[0003]

As shown in FIG. 2, for example, a metal film is formed on one surface of a polarizing cloth 11 woven using a polarizing single fiber 12 and a non-polarizing single fiber 13 having circular cross sections. When the reflective layer 14 is formed by vapor deposition to produce a reflective screen 15 as shown in FIG. 3, the unevenness of the reflective layer is deep, so that the viewing angle becomes excessively wide as shown in FIG. May be impaired. As a means for solving this problem, a method of calendering the polarizing cloth 11 to flatten the fiber cross section can be considered, but this method alone cannot sufficiently solve such a problem.

An object of the present invention is to provide a reflection type screen capable of obtaining a clear and high quality projected image at an appropriate viewing angle even in a bright environment.

[0005]

The object of the present invention is to absorb light having a vibration direction of an electric field parallel to the fiber axis (longitudinal direction of the fiber) (hereinafter, the vibration direction of the electric field is referred to as a polarization direction), Polarized single fiber having the property of transmitting light having a polarization direction orthogonal to the axis, and a non-polarized transparent single fiber,
These two single fibers are characterized by having a transparent layer for smoothing the unevenness of the polarizing cloth and a reflective layer provided on the transparent layer on one surface of a polarizing cloth configured to cross each other. Reflective screen.

[0006]

In the reflection type screen of the present invention, since the reflection surface side of the polarizing cloth is coated with the transparent layer, the unevenness of the reflection surface of the polarizing cloth is reduced, and the reflection surface becomes relatively smooth. The smoothness can be controlled by changing the thickness of the transparent layer and the type of the resin constituting the transparent layer. Therefore, with the reflective screen of the present invention, the viewing angle can be easily controlled, and a bright screen can be displayed with an appropriate viewing angle. Further, since the surface of the reflective screen (projector side) is made of a non-smooth polarizing cloth, the projected light is not specularly reflected, and the generation of a virtual image due to reflection of light from the light source or external light can be prevented.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the reflection type screen of the present invention. The polarizing cloth 1 shown in FIG. 1 has a structure similar to that of the polarizing cloth shown in FIG. 2, and absorbs light having a polarization direction parallel to the fiber axis and transmits light having a polarization direction orthogonal to the fiber axis. And a non-polarized transparent single fiber (not shown) are arranged so as to cross each other. In the reflective screen of the present invention, on one surface of the polarizing cloth 1, a transparent layer 3 for smoothing irregularities of the polarizing cloth made of a transparent resin or the like and a reflecting layer 4 made of metal or the like are laminated. As shown in FIG.
The surface of the transparent layer 3 on the side of the reflective layer 4 only needs to be substantially smooth, and may have low irregularities.

The transparent layer 3 and the reflective layer 4 are formed, for example, by sandwiching the polarizing cloth 1 between a roller having an acrylic resin solution on the surface thereof and a roller not having the resin thereon. A transparent layer 3 having a thickness of about 20 μm is formed, and thereafter, for example, aluminum is formed on the surface of the transparent layer 3 of the polarizing cloth 1 by vapor deposition to a thickness of about 1000 Å. Further, the reflection layer 4 of the polarizing cloth 1 and a thickness of about 40
After laminating a screen support 5 made of a soft PVC (polyvinyl chloride) sheet of 0 μm, the polarizing cloth 1 is cut into a predetermined size, and a winding machine can be provided.

The polarized monofilament 1 used in the present invention is obtained by adding a polarization-developing substance composed of iodine or a dichroic organic dye to a fiber composed of a polyvinyl alcohol, ethylene vinyl alcohol copolymer or the like having an affinity for the substance. This fiber is produced by stretching in the longitudinal direction. The iodine clusters and the dichroic organic dyes are oriented in the direction in which the fibers are stretched in the fibers to exhibit a polarizing function. As a result, the polarized single fiber 1 transmits light having a polarization direction orthogonal to the fiber axis (longitudinal direction) and absorbs light having a polarization direction parallel to the fiber axis.

An example of a method for producing the polarizing single fiber 1 is as follows. First, polyvinyl alcohol (PV
After spinning A), this is immersed in a mixed aqueous solution of iodine and an alkali iodide. Next, the polarizing single fiber 1 is obtained by stretching by a factor of 1.5 to 15 times. Alternatively, the polarized single fiber 1 can be obtained by spinning the PVA, stretching it first, and immersing it in a mixed aqueous solution of iodine and an alkali iodide. The polarizing monofilament 1 uses another polymer such as an ethylene vinyl alcohol copolymer instead of polyvinyl alcohol, and adds a dichroic organic dye such as neutral gray before or after spinning instead of iodine. It is also possible to produce by.

The cross-sectional structure of the polarizing single fiber 1 can be set to various shapes such as a circle, an ellipse, and a shape close to a square.
Different shapes may be used. Polarized single fiber 1
Is determined by conditions such as weaving properties in combination with non-polarizing fibers, flexibility required to wind up the screen when not in use, resolution of projected images, and prevention of moire based on the periodic arrangement of liquid crystal pixels and fibers. In general, the thickness is preferably from 10 to several hundreds μm.

[0012]

According to the reflection type screen of the present invention, the viewing angle is optimized and the projection light can be effectively reflected only within a predetermined viewing angle, so that a bright image can be displayed. In addition, since the surface of the screen (on the side of the projector) is made of a non-smooth polarizing cloth, it does not specularly reflect light from the light source or external light. Therefore, a clear and high quality projected image can be obtained even in a bright environment.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an example of a reflection type screen of the present invention.

FIG. 2 is a schematic perspective view showing an example of a polarizing cloth.

FIG. 3 is a schematic sectional view of an example of a conventional reflective screen.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polarizing cloth 2 Polarizing single fiber 3 Reflective layer 4 Transparent layer 5 Screen support

Continuation of the front page (56) References JP-A-55-138735 (JP, A) JP-A-3-287244 (JP, A) JP-A-4-318829 (JP, A) JP-A-2-267536 (JP) JP-A-64-77085 (JP, A) JP-A-3-150546 (JP, A) JP-A-2-163731 (JP, A) JP-A-50-144440 (JP, A) 49-90533 (JP, A) JP-A-3-53232 (JP, A) JP-A-6-230476 (JP, A) JP-A-6-167746 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03B 21/60

Claims (1)

(57) [Claims] 1. A polarizing monofilament which absorbs light having a vibration direction of an electric field parallel to the fiber axis and transmits light having a vibration direction of an electric field perpendicular to the fiber axis, and a transparent monofilament having no polarization. And a transparent layer for smoothing the unevenness of the polarizing cloth on one surface of a polarizing cloth formed by cross-arranging the polarizing single fiber and the non-polarizing transparent single fiber. A reflective screen having a reflective layer provided on a transparent layer.