JP2005221985A - Reflection-type polarizing screen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provided a reflection-type polarizing screen with the glare alleviated. <P>SOLUTION: In the reflection-type polarizing screen 1, which is stuck with the reflection film 3 of metal film on the one side of the polarized woven textile 2, the space between the reflection film 3 and the polarizing woven textile 2 are adhered with the adhesive bond 4. The air in the space formed by the reflection film 3 and the polarizing woven textile 2 is almost removed by filling the adhesive bond 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a reflective polarizing screen for use in an image system equipped with a liquid crystal display.

  In recent years, liquid crystal display systems are used not only for video projection such as TV but also for connecting to a computer and projecting its screen. Under the environment of strong reflection on the top, the contrast of the image is insufficient, and especially for a liquid crystal projection image with a large screen, it is necessary to view the image in a dark room.

Therefore, as a means to enhance the contrast of the image by reducing the amount of reflection of the illumination light on the screen without damaging the image light, a polarizer in which the electric field vibration surface of the transmitted polarized light coincides with the linear polarization of the liquid crystal image A technique is known in which the screen is covered and the electric field vibration plane is oriented vertically to efficiently remove the illumination light irradiated from the ceiling of the projection room (see Patent Document 1).
Japanese Patent Publication No. 5-54677

On the other hand, it is required that the screen is easily enlarged and can be easily wound. As a means for comprehensively realizing these various conditions, a technique has been proposed in which a screen is formed of a polarizing woven fabric having the function of a polarizing lens array (see Patent Document 2).
Japanese Patent Laid-Open No. 5-197026

  Such a polarizing woven fabric is generally composed of a polarizing fiber and a non-polarizing fiber, and the polarizing fiber has a polarization-expressing substance such as a dichroic dye, and has high affinity and high transparency, such as polyvinyl alcohol, ethylene- It is formed by being contained in a fiber made of a vinyl alcohol copolymer or the like. And since this fiber is extended | stretched in the fiber length direction, the polarization | polarized-light expression substance in a fiber will orientate and polarization performance will express.

  As the non-polarizing fiber, a fiber made of a general-purpose polymer such as nylon or polyester can be used, and a highly transparent fiber is used like the polarizing fiber.

A polarizing woven fabric composed of the fibers described above produces a lens effect due to the cross-sectional shape of the fiber and the bent shape of the woven fabric. The lens effect is adjusted by applying a calendering process or applying a transparent resin to the polarizing woven fabric. can do. In such a polarizing woven screen, as a technique for increasing the light reflectance, a technique in which a metal thin film or a film having a metal thin film formed on one side is bonded to one side of the polarizing woven cloth has been proposed (see Patent Document 3). ).
JP-A-9-146173

  However, the polarizing woven screen has a problem that the image is glaring, and there is no means for sufficiently solving this problem.

  An object of the present invention is to provide a reflective polarizing screen with reduced glare.

  In order to achieve the above object, the reflective polarizing screen of the present invention is a reflective polarizing screen in which a reflective film having a metal thin film is attached to one side of a polarizing woven cloth, and the gap between the reflective film and the polarizing woven cloth is It is characterized in that the air in the space formed by the adhesive film and the reflective film and the polarizing woven fabric is almost removed by filling with the adhesive.

  The polarized woven fabric brightens the image and improves the contrast. Here, when the reflective film and the polarizing woven fabric are joined by an adhesive, if there is air in the space formed by the reflective film and the polarizing woven fabric, the reflective and refracting action looks different from the adhesive part. Cause glare. According to the said structure, since the air of the space formed with such a reflecting film and polarizing woven fabric is removed by filling with an adhesive agent, glare can be suppressed.

  The reflective film is preferably formed by forming a metal thin film on one surface of the resin film.

  According to the reflective polarizing screen of the present invention, it is possible to obtain a reflective polarizing screen having a bright image, good contrast, and no glare.

Embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the reflective polarizing screen 1 of the present invention is configured by attaching a reflective film 3 to the back surface of a polarizing woven fabric 2. The screen 1 reflects video light from a liquid crystal projector made up of an LCD (Liquid Crystal Display) and projects an image. At this time, conventionally, as shown in FIG. 2, the bonded portion by the transparent adhesive 4 was only a part of the polarizing woven fabric 2. For this reason, it has been found that this bonding portion causes so-called refractive index matching and has a reflection and refraction action that is different from the portion not in contact with the adhesive 4, thereby causing glare. Therefore, in the present invention, as shown in FIG. 3, the space between the polarizing woven fabric 2 and the reflective film 3 is filled with an adhesive 4, and air is removed from this space, thereby the reflective film of the polarizing woven fabric 2. It was found that all the unevenness on the 3 side was filled with the transparent adhesive 4, whereby glare can be suppressed. In this state, the back half of the cross section of the fiber forming the polarizing woven fabric 2 is filled with the adhesive 4. Further, as shown in FIG. 4, a reinforcing sheet 6 may be bonded to the back surface of the reflective film 3.

  In the polarizing woven fabric 2 according to the present invention, at least one of the warp 22 and the weft 21 is composed of the above-described polarizing fiber. In this embodiment, as shown in FIG. 5, the weft 21 of the polarizing woven fabric 2 is a polarizing fiber, the warp 22 is a non-polarizing transparent single fiber, and these yarns 21 and 22 are a satin weave. . The cross-sectional shape of the polarizing fiber is, for example, a circular shape, an elliptical shape, a shape close to a square shape, or the like, and different shapes may be used. However, the light diffusion due to the lens effect of the cross-section is made uniform. The cross-sectional shape is preferably set in consideration of the viewing angle characteristic and the gain balance. In addition to the polarizing fibers, polyamides such as nylon 6 and nylon 66, non-polarizing fibers such as polyester, polyolefin, and polyvinyl alcohol can be used together. Further, the cross-sectional shape of the non-polarizing fiber is the same as that of the polarizing fiber, and is preferably a cross-section that can make light diffusion uniform due to the lens effect of the cross-section. It is preferable that

  The polarizing fiber which comprises the polarizing woven fabric 2 of this invention is demonstrated. The material of the polarizing fiber is preferably polyvinyl alcohol or an ethylene-vinyl alcohol-based copolymer in which a polarization-expressing substance such as a dichroic dye is blended, and in view of obtaining a fiber whose cross-sectional shape is almost a perfect circle. -Vinyl alcohol copolymers are particularly preferred.

  The weaving method of the polarizing woven fabric 2 is not particularly limited, but satin weaving is preferable in that the woven density of the polarizing fibers can be increased.

  In the present invention, the lens effect can be adjusted by pressing the polarizing woven fabric 2 obtained as described above or applying a transparent resin.

  As the reflective film 3 bonded to the polarizing woven fabric 2 in the present invention, a metal thin film (referred to as a metal thin film A) or a resin in which a metal thin film (referred to as a metal thin film B) is formed on the surface shown in the embodiment of FIG. Film 8 is used. These metal thin films A and B and film may be selected in consideration of reflectivity, durability, and ease of winding. The thickness of the metal thin film A is 1 μm or more and 50 μm or less, preferably 5 μm or more and 30 μm or less. When the thickness is less than 1 μm, the strength of the metal thin film A is insufficient, and the handleability during processing is deteriorated. On the other hand, when the thickness exceeds 50 μm, the metal thin film A becomes rigid, the flexibility of the polarizing screen is impaired, and the winding property of the screen is deteriorated.

  The thickness of the metal thin film B is 200 angstroms or more, preferably 500 angstroms or more. When the thickness is less than 200 angstroms, a high screen gain cannot be obtained because the reflectance of the light reflecting layer is low. The upper limit of the thickness is not particularly limited as long as the flexibility of the screen is not impaired, but it is preferably 1 μm or less from the viewpoint of processability and planarity.

  The film for forming the metal thin film B is not particularly limited as long as it does not inhibit the type of metal, the adhesion to the reinforcing sheet 6 and the flexibility of the screen, but the thickness is 5 μm or more and 300 μm or less. Preferably, a film made of a resin such as polyolefin, polyester, polyamide, or vinyl chloride is preferable. When the thickness of the film exceeds 300 μm, the polarizing screen becomes rigid and difficult to wind. On the other hand, when the thickness of the film is less than 5 μm, formation of the metal thin film B becomes difficult.

  It is more preferable that the composite film on which the metal thin film B is formed is the reflective film 3 in that the metal thin film is less likely to wrinkle.

  Further, when a composite film having a metal thin film B formed thereon is attached to the polarizing woven cloth 2, the metal surface may be attached to the polarizing woven cloth 2, or the metal thin film B is formed on the transparent film and the film face is attached. It may be a surface. Examples of the method for forming the metal thin film B on the film include vacuum deposition and sputtering. The metal type of the metal thin film A and the metal thin film B is preferably higher in reflectance and more uniform in spectral reflectance distribution in the visible light range, and preferably less in oxidative degradation. Examples of such a metal include silver and aluminum, and aluminum is preferable in terms of oxidative degradation.

  Any adhesive 4 can be used as long as it is transparent when the composite film having the metal thin film B formed thereon is attached to the polarizing woven fabric 2. As a bonding method, a method in which the air in the space formed by the reflective film 3 and the polarizing woven fabric 2 is substantially removed by filling with the adhesive 4 can be appropriately selected and applied from known methods. Here, even if not all the air is completely removed from the space formed by the reflective film 3 and the polarizing woven fabric 2, the effects of the present invention can be achieved, but 90% or more of the volume of the space. Is preferably filled with the adhesive 4.

Hereinafter, the present invention will be described by way of examples.
A dichroic direct dye and an ethylene vinyl alcohol copolymer were mixed, fiberized by a melt spinning method, and then drawn to obtain a polarizing fiber having a substantially circular cross section and a diameter of 100 μm.

  Weaving this polarizing fiber as weft and transparent single fiber of nylon 6 (diameter 50μm) as non-polarizing fiber as warp, weaving under the conditions of warp density of 90 / inch and weft density of 200 / inch by weft weaving Went. The surface where the wefts are mainly exposed (the surface shown in FIG. 5) was defined as the surface.

About 15 g / m ^{2 of} urethane resin was applied to both surfaces of the obtained woven fabric by a knife coater to form a protective transparent resin layer. Next, aluminum was vapor-deposited on a polyethylene terephthalate film having a thickness of 50 μm to form a metal thin film having a thickness of 800 Å, and the reflection sheet 3 shown in FIG. 3 used as a reflection film was manufactured. Subsequently, the metal surface of the reflective sheet 3 was bonded to the back surface of the polarizing woven fabric 2 using a transparent adhesive of urethane adhesive. At this time, an adhesive was applied to the back surface of the woven fabric 2 with a thickness of about 40 μm so that no bubbles remained in the adhesive layer 4, and the woven fabric 2 and the reflective sheet 3 were bonded together while being pressed with a roller. When the cross section of the screen was observed, there was no air layer between the woven fabric 2 and the reflection sheet 3, and it was filled with the adhesive 4.

  Next, as shown in FIG. 4, a soft polyvinyl chloride resin sheet having a thickness of 300 μm is used as the reinforcing sheet 6, and the reflective film 3 side of the polarizing woven fabric 2 is bonded using an adhesive 4 to 150 × 150 cm. The screen was cut into a size and fitted with a winding jig made of an aluminum alloy pipe to produce a screen.

Comparative Example 1

  When the reflective sheet 3 and the polarizing woven fabric 2 are bonded together, the adhesive 4 is applied to the back surface of the woven fabric 2 with a thickness of about 10 μm, and the woven fabric 2 and the reflective sheet 3 are bonded together while being pressed with a roller. Produced a screen in the same manner as in Example 1. When the cross section of the screen was observed, only the top of the woven fabric 2 was bonded to the reflective sheet 3, and an air layer was present between the fibers.

  Images of the liquid crystal projector were projected on the screens of the examples and comparative examples, and the images were evaluated in a room of 500 lux.

  According to 10 randomly selected evaluators, all 10 were judged that the screen of the example had a bright image, good contrast, and was not concerned with glare.

  On the other hand, all the 10 screens of the comparative example were judged to be unacceptable because the video was bright and the contrast was good, but the glare was conspicuous.

It is sectional drawing which shows the reflective polarizing screen which concerns on one Embodiment of this invention. It is sectional drawing which shows the conventional reflective polarizing screen. It is sectional drawing which shows the principal part of the reflective polarizing screen which concerns on one Embodiment of this invention. It is sectional drawing which shows the reflective polarizing screen which concerns on other embodiment of this invention. It is a front view of the polarizing woven fabric of the reflective polarizing screen which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reflective type polarizing screen 2 Polarized woven fabric 3 Reflective film 4 Adhesive 8 Film B Metal thin film

Claims (2)

In a reflective polarizing screen in which a reflective film having a metal thin film is attached to one side of a polarizing woven fabric,
A reflective polarizing screen characterized in that the reflective film and the polarizing woven fabric are joined with an adhesive, and the air in the space formed by the reflective film and the polarizing woven fabric is substantially removed by filling with the adhesive. .   2. The reflective polarizing screen according to claim 1, wherein the reflective film is formed by forming a metal thin film on one surface of a resin film.

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