JP2006146019A - Screen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflection type screen and a projection type screen which are screens used for image projection by a liquid crystal projector etc., incur less color shift without reflection not only of a fluorescent lamp but sunlight and provide clear contrast. <P>SOLUTION: The screen is characterized in that it has a layered product stacking a surface layer consisting of transparent or translucent resin layer in which black pigment is distributed on one surface and an optical diffusion layer in which transparent particles are distributed in the transparent resin layer on the other surface of a transparent base on its surface and the surface layer has many of at least two kinds of recessed parts with different opening area and/or depth on the surface in random arrangement. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a screen used for image projection, such as a liquid crystal projector, and relates to a reflective screen and a projection screen used for displaying a projected image with little color shift and clear contrast.

In a screen used for image projection such as a liquid crystal projector, there is an increasing demand for projecting an image not only in a dark room but also in a state where the room is brightly illuminated under fluorescent light or sunlight.
However, when the outside is brightened, a phenomenon occurs in which the screen image is whitened due to reflection or reflection of external light, and further, the contrast is lowered and the image is blurred.
Further, when the screen is viewed from an oblique direction, the color of the display image is not reproduced in a natural color, and a so-called color shift phenomenon in which a purple color or a green color occurs may occur.

As a conventional technique for solving these problems in a screen, for example, a reflective screen provided with a transparent resin layer having fine irregularities formed on the surface is known. (Patent Document 1)
In Patent Document 1, in order to increase the contrast, a light absorbing portion is provided under a transparent resin layer, which is a printed layer on which a grid or multiple strips of black or gray ink is printed. However, if the area of the printed part is increased to increase the contrast, the total light transmittance is reduced and the image becomes dark, and if the printing layer is increased to increase the hiding power, the viewing angle is reduced. .
In Patent Document 1, no consideration is given to preventing the color shift phenomenon by devising the shape and arrangement of fine irregularities on the surface of the transparent resin layer.

Further, as a technique for providing a high-contrast reflective screen, Patent Document 2 discloses a light diffusing particle screen using a transparent matte colored ink layer and a metal powder layer on the surface.
In the technique disclosed in Patent Document 2, with respect to the reflection when receiving external light such as fluorescent light or sunlight, a countermeasure is taken with a transparent matte colored ink layer on the surface, but a light diffusion layer is used. There is a problem that the uniformity of brightness is not sufficient because it is not provided.

  Furthermore, a light reflecting layer in which scaly flakes are dispersed in a transparent resin layer, and a light diffusing layer having a concavo-convex shape in which calcite microcrystalline particles are dispersed in a light transmitting resin are provided, and only in the concave portion on the surface of the light diffusing layer. A reflective screen provided with a light absorption layer made of an achromatic transparent resin made of a dye or a pigment is disclosed in Patent Document 3. The role of the light absorbing material used in the light absorbing layer is to absorb the extraneous light coming from the side surface and reduce the glare of the screen.

However, in order to suppress reflection of extraneous light and increase the contrast, if the area of the concave portion where the light absorption layer exists is widened, the total light transmittance is reduced and the image becomes dark, and if the concave layer is thickened, the viewing angle is narrowed. There was a problem that.
In Patent Document 3, no consideration is given to preventing the color shift phenomenon by devising the shape and arrangement of irregularities on the surface of the transparent resin layer.

Japanese Patent Application Laid-Open No. 2004-151867 discloses a technique related to a reflective projection screen including a light absorption layer, a light diffusion layer, and a light reflection layer.
1 to 4 of Patent Document 4, it is shown that the surface of the light absorption layer in which an achromatic dye or pigment that is a light absorbing material is dispersed in a transparent resin has an uneven shape.
The configuration of Patent Document 4 has a problem that the uneven shape cannot be accurately controlled because the light absorbing layer is applied on the light diffusion layer having the uneven shape. In addition, there is a problem that a complicated process is required and manufacturing cannot be advantageously performed in terms of cost.
In other words, Patent Document 4 does not take into account the prevention of the color shift phenomenon by devising the shape and arrangement of the irregularities on the surface of the transparent resin layer.

Thus, in a screen used for image projection, such as a liquid crystal projector, it is possible to completely solve the problem of preventing whitening of the image and a decrease in contrast due to reflection of external light and further reducing color shift. The simple and practical technology that can be done is not achieved even today.
JP-A-6-230474 JP-A-9-274254 JP-A-10-260475 Japanese Patent Laid-Open No. 10-282578

  An object of the present invention is a screen used for image projection of a liquid crystal projector or the like, and further has a small color shift, a reflection type screen having a clear contrast without reflection due to reflection of sunlight as well as a fluorescent lamp, and It is to provide a projection type screen.

In order to solve the above problems, the inventors of the present invention have intensively studied, and as a result, the surface has a large number of concave portions whose sizes and positions are randomly arranged, and the light absorbing material is dispersed in the surface layer. The present invention has been completed by finding that the above-mentioned problems can be solved by providing a surface layer made of a transparent or translucent resin layer.
That is, the present invention is to disperse transparent particles in a transparent substrate, a surface layer composed of a transparent or translucent resin layer in which a black pigment is dispersed on one side, and a transparent resin layer on the other side. A screen having a laminate on which light diffusion layers are laminated on the surface, wherein the surface layer has at least two types of concave portions having different opening widths and / or maximum depths on the surface in a random arrangement. Provide a featured screen. Here, it is preferable that the concave portion is formed by transferring the pattern of the shaping film, and it is preferable that the light absorbing material is dispersed in the light diffusion layer.
Although such a screen can be used as it is as a transmissive screen, it can be used as a reflective screen by providing a reflective layer on the light diffusion layer side.

According to the present invention, the light-absorbing material is dispersed in a large number of recesses and surface layers randomly arranged in size and position on the surface, so that the color shift phenomenon can be reduced and the contrast is clear. A reflective screen and a transmissive screen used for displaying a projected image can be provided with a simple configuration.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram illustrating a schematic structure of a transmission screen according to the present invention, and is a diagram illustrating a schematic structure of a screen in which a black pigment is added as a light absorbing material only to a surface layer. In FIG. 1, 1 is a transparent substrate, 2 is a surface layer, 3 is a black pigment of the surface layer, and 4 is an optical film formed by laminating a substrate 1 and a resin layer 2. Reference numeral 5 denotes a support, 7 denotes a light diffusion layer, and 9 denotes a light diffusion particle.

As the transparent substrate 1 used in the present invention, a transparent glass plate, a resin layer made of a transparent resin, for example, a resin plate, a resin film or a sheet (in the present specification, these are simply referred to as “film”. And the like. As the transparent resin, polycarbonate, triacetyl cellulose, polyester (polyethylene terephthalate (PET), polyethylene naphthalate, etc.), polystyrene, polyolefin, polyurethane resin, polyacrylic resin, or the like can be used. In particular, triacetyl cellulose and polyester are preferably used. These resin layers may or may not be stretched. Biaxial stretching is preferable because it is excellent in strength. When used in a liquid crystal projector, unintentional coloring may occur due to retardation of the resin layer. From the viewpoint of avoiding this, an unstretched film or a uniaxially stretched film, particularly a triacetyl cellulose film or a uniaxially stretched polyester film is particularly preferably used.
The thickness of the transparent substrate 1 is determined according to the use conditions of the screen, but when the screen is used in a film form, a thickness of about 20 to 200 μm is usually used.

The surface layer 2 in the present invention is formed by mixing a black pigment into a transparent or translucent resin. On the surface of the surface layer 2, a large number of at least two types of concave portions having different opening width and / or maximum depth values are provided in a random arrangement. These recesses are preferably formed by transferring the pattern of the shaping film. Although there is no restriction | limiting in resin which forms the surface layer 2, Since the pattern of a shaping film is transcribe | transferred, curable resins, such as a thermosetting resin, an ultraviolet curable resin, and an electron beam curable resin, are used suitably. Among these curable resins, an ultraviolet curable resin is preferable because the equipment for resin curing is simple and excellent in workability. Examples of the ultraviolet curable resin include photopolymerizable prepolymers and / or monomers, and other monofunctional or polyfunctional monomers, various polymers, and photopolymerization initiators as necessary (acetophenones, benzophenones, Michler's ketone). Benzyl, benzoin, benzoin ether, benzyl ketals, thioxanthones, etc.) and a sensitizer (amines, diethylaminoethyl methacrylate, etc.). Here, examples of the photopolymerizable prepolymer include polyester acrylate, polyester urethane acrylate, epoxy acrylate, and polyol acrylate. Examples of the photopolymerizable monomer include monofunctional acrylate, bifunctional acrylate, and trifunctional or higher acrylate. Etc. are exemplified. In addition to the above, phosphazene resins are also suitably used as the photopolymerizable prepolymer or monomer.
As the thermosetting resin and the electron beam curable resin, the same ultraviolet curable resin as described above is used. However, the electron beam curable resin does not require the addition of a polymerization initiator.

As the black pigment 3 as the light absorbing material used for the surface layer 2 in the present invention, black particles such as carbon black, graphite, aniline black and cyanine black can be used. These pigments are preferably completely black, but may be somewhat colored depending on the lighting of the room or the projected image. Of these pigments, carbon black is particularly preferably used. The particle diameter of the black pigment 3 is preferably 0.1 to 5 μm, and more preferably 0.2 to 0.5 μm.
By dispersing the black pigment 3 in the surface layer 2, external light that has entered the interior without being reflected by the irregularities formed on the surface of the surface layer 2 is absorbed by the black pigment 3, and is scattered or reflected inside the surface layer 2. Since the external light emitted is reduced, the contrast is improved.

As a method for forming the surface layer 2, first, a peelable shaping film having a release treatment such as randomly arranging a large number of particles such as at least two kinds of beads having different sizes on the surface and applying a silicone resin. Prepare. Next, a curable resin is applied to the transparent substrate 1, and the prepared shaping film is bonded to the surface of the uncured curable resin layer. At least two types with different maximum opening width and / or depth when the moldable film is removed after the curable resin layer is cured with heat, ultraviolet rays or radiation such as electron beam with the moldable film attached Many concave portions are formed on the surface in a random arrangement. Such recesses are preferably a mixture of small recesses having a maximum opening width and / or depth of 0.01 to 1 μm and large recesses of 10 to 30 μm. The mixing ratio of the small and large recesses is preferably 20 to 80:80 to 20 in terms of the opening area ratio. And it is preferable that the opening by the recessed part in the surface of the surface layer 2 is 50% or more. In this way, when the surface layer 2 is formed using a shaping film, a portion where a relatively smooth small recess exists and a portion where a large recess whose surface is greatly roughened exist. When these are mixed and the black pigment 3 is mixed, external light reflection and glare can be surely prevented, and the light penetrates into the interior without being reflected by the unevenness formed on the surface of the surface layer 2. It is possible to prevent projection light from a projector or the like from being interfered with by external light. That is, by mixing with large concave portions, it is possible to prevent regularity in the arrangement of the small concave portions, and to prevent color shift and unnecessary coloring.

In addition, it is preferable that the shaping film is peeled off. However, when the resin forming the surface layer is a curable resin, the interface with the shaping film tends to peel off due to curing of the resin. Depending on the resin forming the surface layer, the peeling treatment may not be performed. And a shaping film can be utilized as it is as a protective film, without removing until just before the screen of this invention is used. In particular, when shipping the screen of the present invention as a roll product, the protective film bonding step can be omitted compared to the case where the protective film is pasted after embossing the embossing process. Contributes to improving productivity and reducing manufacturing costs.

As the light diffusing particles 9 used in the light diffusing layer 7 in the present invention, transparent beads or particles such as glass or resin can be used. The shape of the light diffusion particle 9 may be an indefinite shape, a spherical shape, a rugby ball shape, or a flat particle. The light diffusing particles 9 preferably have a particle diameter in the range of about 1 to 20 μm.
The transparent resin for forming the light diffusion layer 7 is not particularly limited. As long as it is transparent, it may be a curable resin similar to the above surface layer 2 or a thermoplastic resin. From the viewpoint of transparency, an acrylic copolymer is preferably used.

The support 5 may be provided as necessary, for example, when the screen is given thickness or rigidity, or when used as a substrate when forming the light diffusion layer. And determined by manufacturing conditions. In the case of winding up in a roll shape, the thickness of the support 5 is usually about 20 to 100 μm. When the bonding screen is not wound on a wall or the like, the thickness of the support 5 is not particularly limited, and may be omitted in some cases, such as when a light diffusing layer is formed directly on a transparent base material of the surface layer. good. The material may be an inflexible plate member.

FIG. 2 is a diagram showing a schematic structure of a transmissive screen according to another example of the present invention, and is a diagram showing a schematic structure of a screen in which a black pigment 8 is also added to the light diffusion layer 7 as a light absorbing material.
The black pigment 8 put in the light diffusion layer 7 can be the same as the black pigment 3 put in the surface layer 2, but it is not necessarily the same, and different types may be used.

FIG. 3 is a diagram showing a schematic structure of a reflective screen according to the present invention, and is a diagram showing a schematic structure of a screen in which a reflective layer 6 is provided on the transmissive screen of FIG.
On one side of the support 5, a reflective layer 6 made of a resin layer or a metal vapor-deposited layer 10 containing a reflector such as a metal powder or a scale-like inorganic substance is provided in order to give a function of reflecting light.
When the screen is of a reflective type, the support 5 can be made of a transparent material such as a woven fabric or a non-woven fabric as well as a transparent material similar to the transparent substrate 1.

FIG. 4 is a diagram showing a schematic structure of a reflective screen according to another example of the present invention, and is a diagram showing a schematic structure of a screen in which a reflective layer 6 is provided on the transmissive screen of FIG.

EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to this Example.

(Examples 1-5)
Creation of shaped film Particles consisting of uncured thermosetting acrylic resin with silica beads having a particle size in the range of 2-5 μm (small beads) and silica beads having a size of 10-30 μm (large beads) A coating solution prepared by dispersing two types of particles having different diameters is applied to the surface of a polyester film (Toyobo Co., Ltd., A4300, thickness 50 μm) by the reverse method, and then at 120 ° C. for 3 minutes. A cured film A was prepared by heat-curing and randomly projecting convex peaks having different heights on the surface of the film and peeling the irregular surface with addition silicone.

FIG. 5 shows a photomicrograph of the shaped film A. Large and small convex mountains are arranged randomly.

Adjustment of resin for forming surface layer Photopolymerization initiator (manufactured by Ciba Specialty Chemical Co., Ltd.) and acrylate copolymer (manufactured by Soken Chemical Co., Ltd., SW-11A) as curable resin to be surface layer 2 , Irgacure 184) and 0.1%, 0.05%, 0.04%, 0.03%, 0.03%, carbon black having a particle size of 2 to 5 μm as the black pigment 3 are added. Five kinds of resins were added to form the surface layer 2 by adding at 01 wt% and stirring and mixing uniformly.

Preparation of optical film Each resin for forming the prepared surface layer 2 is cast-applied on the shaping film A, and a PET film 100 [mu] m (O-300E, manufactured by Diafoil) is used as a transparent substrate 1 thereon. Was pasted. Thereafter, the resin layer was cured with 300 mJ ultraviolet rays, and the moldable film was peeled off to produce five types of optical films 4.

FIG. 7 shows a micrograph of the surface of the optical film 4 to be the surface layer 2. A place where a relatively smooth small recess exists and a place where a large recess whose surface is greatly roughened exist.
The surface of the five types of optical films 4 thus prepared was measured at 1,500 points in the width direction with an average interval between uneven peaks and valleys of 80 to 150 μm (JIS
The measured values of the surface roughness according to B0651-2001 were Rsm: 80 to 150 μm, Ra: 2.0 to 3.0 μm, Rz: 10 to 20 μm).

Formation of light diffusing layer Particle size of acrylic copolymer adhesive (Saiden Chemical Co., Ltd., Cybinol AT-192) added with polyisocyanate crosslinking agent (Soken Chemical Co., Ltd., curing agent L-45) 1 to 10 μm of a silicone-based transparent resin light scattering particle 9 is added at a solid content ratio of 5% by weight and uniformly stirred and mixed to form a resin for forming the light diffusion layer 7. A light diffusing layer 7 was prepared by applying a reverse method to Lumirror X-42T manufactured by Toray Industries, Inc. and heating at 100 ° C. for 10 minutes to cure the resin layer.

Creation of transmission type screen The five types of optical films 4 obtained above and the light diffusing layer 7 are bonded with a transparent acrylic adhesive (not shown), and the transmission type screen 11 shown in FIG. A type was prepared and designated as Examples 1-5.

Evaluation of Transmission Screens The five types of performance evaluation methods of the transmission screens 11 were performed using the total light transmittance and contrast as indices. The total light transmittance was measured using a haze meter (manufactured by Nippon Denshoku Co., Ltd., HD-2000) as an analyzer.
An image including a white image and a black image was projected from the back onto the obtained transmissive screen with a liquid crystal projector in a room having a brightness of 150 lux, and the appearance was evaluated. “A” when the black image is “very clearly identifiable”, “B” when “clearly identifiable”, “C” when “identifiable”, “D” when “slightly blurred but identifiable” , “×” indicates the case where “the image cannot be identified”.
The effect of preventing the color shift phenomenon was evaluated by measuring the angle from the front in which an unintentional color is generated in the display image when the transmissive screen is gradually shifted in the right direction from the front.
The evaluation results are shown in Table 1.

(Comparative Examples 1-5)
Production of moldable film Comparative examples 1 to 5 were sequentially performed in the same procedure as moldable film A used in Examples 1 to 5 except that only one type of silica beads (in the beads) in the range of 5 to 10 μm was used. A shaped film B to be used was prepared.

FIG. 6 shows a photomicrograph of the shaped film B. Compared with the shaping film A, the convex peaks having a medium size are relatively regularly arranged.

Adjustment of resin for forming surface layer Resin for forming the surface layer used in Comparative Examples 1 to 5 was prepared in the same manner as that used in Examples 1 to 5.

Production of optical film Five types of optical films used in Comparative Examples 1 to 5 were produced sequentially in the same procedure as in Examples 1 to 5 except that the shaping film B was used.
FIG. 8 shows a photomicrograph of the surface of the optical film 4 to be the surface layer 2. Irregularities are formed relatively regularly.
The created optical film has an average interval between uneven peaks and valleys measured at 1,500 points in the width direction and is 30 to 60 μm (JIS
The measured values of the surface roughness according to B0651-2001 were Rsm: 30 to 60 μm, Ra: 0.5 to 1.5 μm, Rz: 3.0 to 8.0 μm).

Formation of light diffusing layer The light diffusing layer used in Comparative Examples 1-5 was prepared in the same manner as in Examples 1-5.

Creation of transmission type screens By using the optical films used in Comparative Examples 1 to 5, transmission type screens were sequentially prepared in the same procedure as in Examples 1 to 5, and Comparative Examples 1 to 5 were obtained.

Evaluation of transmission screen The transmission screen was evaluated in the same manner as in Examples 1-5.
The evaluation results are shown in Table 1.

(Comparative Example 6)
A transmissive screen was prepared in the same procedure as in Example 1 except that the black pigment was not mixed in the resin forming the surface layer, and evaluation was performed in the same manner as in Example 1.
The evaluation results are shown in Table 1.

(Comparative Example 7)
A transmissive screen was prepared in the same procedure as in Comparative Example 1 except that the black pigment was not mixed into the resin forming the surface layer, and evaluation was performed in the same manner as in Comparative Example 1.
The evaluation results are shown in Table 1.

Table 1

(Examples 6 to 10)
In the light diffusion layer 7, the same black pigment as that used in the surface layer of Example 4 was added as the black pigment 8, and a 900 mm aluminum vapor deposition film was formed as the reflection layer 6 in forming the light diffusion layer 7. Except that the metal vapor-deposited layer 10 made of is provided, five types of reflective screens 12 shown in FIG.
About evaluation, it implemented except having projected the image from the front surface of the reflective screen 12, and having measured the Y value of the black image using the color difference meter (the Nippon Denshoku Co., Ltd. make, SE-2000). Performed as in Example 1.
The evaluation results are shown in Table 2.

(Example 11)
A reflective screen 12 was prepared in the same procedure as in Example 6 except that the black pigment 8 was not mixed in the light diffusion layer 7 and evaluated in the same manner as in Example 6.
The evaluation results are shown in Table 2.

Table 2

Discussion From the evaluation results of Examples 1 to 5 and Comparative Examples 1 to 5, the transmission type screen using the shaping film A is less likely to cause a color shift than the one using the shaping film B. It can be seen that the contrast is improved. Moreover, it can be seen from Comparative Examples 6 and 7 that no black pigment is mixed in the surface layer, there is a problem in contrast if the black pigment is not mixed in the surface layer. And in the transmission type screen which has the surface layer which transcribe | transferred the pattern of the shaping film A used in the present Example, it is preferable that the ratio of the black pigment mixed in a surface layer is 0.03-0.05 weight%. Recognize.
On the other hand, from the evaluation results of Examples 6 to 11, in the reflective screen having the surface layer to which the pattern of the shaping film A used in this example was transferred, the ratio of the black pigment mixed in the light diffusion layer was 0. It turns out that 05-0.08 weight% is more preferable. If the black pigment is not mixed in the light diffusion layer, the Y value increases, but the contrast decreases. If the mixing amount is large, the Y value decreases, and the contrast also decreases. The reason for this is thought to be that the presence of black pigment in the light diffusion layer contributes to the improvement of contrast, but if the mixing amount is too large, it is difficult to transmit light.

INDUSTRIAL APPLICABILITY The present invention is a screen used for image projection such as a liquid crystal projector, and can be used for a reflection type screen and a projection type screen used for displaying a projected image with little color shift and clear contrast.

1 shows a schematic structure of a reflective screen according to the present invention. The schematic structure of the projection type screen of this invention is shown. The schematic structure of the reflection type screen of another embodiment of this invention is shown. The schematic structure of the projection type screen of another embodiment of this invention is shown. It is a microscope picture which shows the surface state of the shaping film A. It is a microscope picture which shows the surface state of the shaping film B. It is a microscope picture which shows the surface state of the surface layer formed with the shaping film A. 2 is a photomicrograph showing the surface state of a surface layer formed of a shaping film B. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent base material 2 Surface layer 3 Black pigment of surface layer 4 Optical film 5 Base material
6 Reflective layer 7 Light diffusing layer 8 Black pigment in light diffusing layer 9 Light diffusing particles
10 Metal deposition layer 11 Transmission type screen
12 Reflective screen

Claims (4)

A transparent base material comprising a transparent or semi-transparent resin layer in which a black pigment is dispersed on one surface, and a light diffusion layer in which transparent particles are dispersed in a transparent resin layer on the other surface. A screen having a laminated body on the surface, wherein the surface layer has at least two kinds of concave portions having different opening widths and / or maximum depths on the surface in a random arrangement.   2. The screen according to claim 1, wherein the concave portion is formed by transferring a pattern of a shaping film. The screen according to claim 1, further comprising a black pigment dispersed in the light diffusion layer. 4. The screen according to claim 1, further comprising a reflective layer on the light diffusion layer side.