JPH06148747A - Screen for projection - Google Patents

Abstract

PURPOSE:To provide the screen for projection which is high in reflectivity, forms bright images even in daylight, has small light directivity, forms the bright images at a wide angle and can be rolled up. CONSTITUTION:This screen for projection has a structure successively laminated with (1) a mat layer mainly consisting of org. spherical fillers and a binder, (2) a metallic thin film layer and (3) a protective layer on a plastic film base material. The reflectivity of white light of the above-mentioned screen is >=10% and the half value angle of the reflectivity is >=30 deg..

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection screen, and more particularly to a projection screen which has a high reflection brightness of light and a small directivity and can be rolled up when not in use.

[0002]

2. Description of the Related Art Conventionally, a projection screen has been widely used as an overhead projector screen in offices and the like. In addition, recently, projection televisions have become widespread along with the enlargement of television screens.
Projection screens are also being used in homes.

However, in the conventional combination of the projector and the projection screen, since the brightness is insufficient, it is necessary to darken the room by a curtain or the like. Therefore, it is desired to improve the brightness of the projection screen as well as the brightness of the projector (high brightness screen).

Also, with an overhead projector,
Recently, an apparatus capable of directly photographing an original such as a paper without using a dedicated transparent film has been developed. In the case of the apparatus, since the reflected light is used, the brightness of the projector is insufficient, and particularly, You need a high brightness projection screen.

Various types of projection screens have been used in the past, but the roll-up type screen is mainly coated with a bead type in which fine glass spheres are attached to the screen surface or a pearl pigment ink. Clear type is used. However, its brightness is not sufficient.

As the high-brightness type, a curved screen using an aluminum foil or an aluminum vapor-deposited sheet is used, but in this case, it is difficult to adopt a winding method, and it is mainly a fixed type. used. In the case of the fixed type, although it has high brightness, it has a drawback that it requires an installation place. For this reason, there is a demand for a high-luminance screen by a winding method, especially for home use.

Further, in the case of a projection television projection screen, since a plurality of people are seen from a relatively short distance, it is necessary to project a clear image at a wide angle. Therefore, as a projection screen, there is a demand for a reflection screen having a high reflection brightness and a small light directivity.

[0008]

The inventor of the present invention has reached the present invention as a result of intensive research to develop a projection screen satisfying the above demands.

Therefore, an object of the present invention is to provide a projection screen which has a high reflection brightness, provides a clear image even in daylight, has a small light directivity and can obtain a clear image even in a wide angle, and can be rolled up. To provide.

[0010]

The object of the present invention is, according to the present invention, (1) a mat layer mainly composed of an organic spherical filler and a binder (binder) on a plastic film substrate, and (2) a metal. It has a structure in which a thin film layer and (3) a protective layer are sequentially laminated, and has a reflection brightness of white light of 1
It is achieved by a projection screen having a reflection brightness half-value angle of 30 degrees or more and 0% or more.

As the plastic film substrate in the present invention, a polyester film is particularly preferable, but a film made of other resins such as polystyrene, polyvinyl chloride, polymethyl acrylate, polycarbonate, acetate resin, polysulfone and the like may be used. . The film substrate may be a single film or a composite film, for example, a composite film of a polyester film and another resin film.

The polyester film has a very smooth surface, and when coating a coating on the polyester film to form surface irregularities, there is an advantage that the surface irregularities of the film itself do not have to be taken into consideration, and further the solvent resistance is high. It also has the advantages of good heat resistance and excellent mechanical performance.

The polyester is a crystalline linear saturated polyester produced from an aromatic dibasic acid or its ester-forming derivative and a diol or its ester-forming derivative, and specifically, polyethylene terephthalate and polypropylene. Preferred examples include terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, and poly (1,4-cyclohexylene dimethylene terephthalate). Further, it may be a copolymer in which a part of these is substituted with another component, or a mixture with a polyalkylene glycol or another resin.

The polyester film can be manufactured by a conventionally known method. For example, the polyester is dried and then melted, extruded from a die (for example, T die, I die, etc.) onto a cooling drum to be rapidly cooled to obtain an unstretched film, and the unstretched film is biaxially stretched and further heat-fixed. It can be manufactured by

The mat layer (1) in the present invention is mainly composed of an organic spherical filler and a binder (binder).

The sphericity of the organic spherical filler is 0.
A spherical filler of 8 or more is preferable, for example, benzoguanamine resin (manufactured by Nippon Shokubai Kagaku Co., Ltd .: trade name Eposter), crosslinked styrene resin (Sumitomo Chemical Co., Ltd .: trade name Fine Pearl), nylon resin, silicone resin (Toshiba Silicone). Examples include Tospearl manufactured by Co., Ltd.

Here, the degree of vacuum of the spherical filler is represented by the ratio of the minor axis to the major axis of the particle (minor axis / major axis), and after the metal is deposited on the particle surface, it is magnified 1 to 30 times with an electron microscope. It can be measured from the image taken.

The average particle size of the organic spherical filler is 1 to 12
It is preferably μm, and more preferably 2 to 10 μm. If the average particle size is less than 1 μm, the surface of the mat layer becomes smooth and the brightness is high, but the directivity is large.
It is not possible to obtain a clear image at a wide angle, while 12 μm
When it exceeds the above range, the brightness becomes extremely low when the directivity is suppressed, so that high brightness and low directivity cannot be satisfied at the same time, which is not preferable.

As the binder (binder), for example, acrylic resin, urethane resin, nitrocellulose, melamine resin, epoxy resin, polyester resin or the like can be used. What is particularly desired for the binder is to exhibit high adhesive strength to both the plastic film and the filler so that the coating film does not peel off or the filler is missing. A heat-resistant binder is preferable since a metal, especially aluminum, is vacuum-deposited on the surface as post-processing.

The ratio of the filler to the binder is an important factor in designing the surface of the coating film. In particular, in the case of a binder having no flattening property and having a flat coating film forming ability, only the presence of the filler is a factor for forming fine unevenness. If the proportion of the filler is too small, protrusions will be scattered only in places on the flat surface of the coated surface, and it will not be possible to impart desirable reflection performance. Further, if the proportion of the filler is too high and exceeds the critical pigment volume concentration (CPVC), the binder penetrates into the overlapping fillers, the recesses of the protrusions are not flat, and the amount of reflected light is sharply reduced. . Therefore, there is a suitable range for the ratio (weight ratio) of the filler to the binder, which is in the range of 1/6 to 1/1. If the ratio of the filler and the binder exceeds 1/1, the brightness will decrease significantly,
On the other hand, when it is less than 1/6, the brightness is high, but the directivity is strong and a clear image cannot be obtained at a wide angle, which is not preferable.

The solvent used for preparing the matte layer coating solution is not particularly limited as long as it does not substantially attack the film and the organic spherical filler, and the solvent conventionally used for film coating can be used. .
Specific examples of such a solvent include methyl ethyl ketone, toluene, cyclohexanone, butyl acetate and the like. The concentration of filler and binder in the paint is preferably about 10 to 50% by weight, more preferably about 20 to 40% by weight.

The thickness of the mat layer preferably has a specific value with respect to the average particle diameter of the organic granular filler, and is preferably 0.
A thickness of 5 to 3.0 times is preferable. When this thickness is less than 0.5 times the average particle size, the brightness is lowered, and high brightness and low directivity cannot be satisfied at the same time. On the other hand, when it exceeds 3.0 times, the brightness is increased but the directivity is increased. Is also strong and not preferable.

Various methods can be used for coating the matte layer coating liquid on the plastic film, for example, Mayer bar coating, reverse coating, kiss roll coating, gravure coating and the like.

The metal thin film layer (2) in the present invention is formed on the mat layer (1), but the forming method is not particularly limited, and physical vapor deposition methods such as vacuum vapor deposition method, sputtering method and ion plating are used. The method etc. can be used. Examples of the metal include aluminum, chromium, silver and the like, but aluminum is preferable in terms of cost. Therefore, it is preferable in terms of cost and performance to form the metal thin film layer by vacuum vapor deposition of aluminum.

The thickness of the metal thin film layer is preferably 20 to 200 nm. If the thickness is less than 20 nm, the reflection characteristics are poor, while if it exceeds 200 nm, it is disadvantageous in cost.
Not preferable.

The protective layer (3) in the present invention is formed on the metal thin film layer (2), but a layer which has been conventionally used as a protective layer for a metal thin film layer can be applied. For example, it can be formed using acrylic resin, polyester resin, nitrocellulose, melamine resin, epoxy resin, or the like.

The protective layer is required to have a function of preventing the metal thin film layer from being scratched and to substantially maintain the surface irregularities of the matte layer. From this point, the thickness of the protective layer is 1 μm.
To 1.0 times the average particle size of the organic spherical filler contained in the mat layer. The upper limit of this thickness is preferably 0.8 times the average particle size. If this thickness is less than 1 μm, the scratch resistance, durability, etc. are reduced and the function as a protective layer is insufficient, while if it exceeds 1.0 times the average particle size of the filler,
Although the surface is flattened to increase the brightness, the directivity becomes strong and it becomes difficult to use in a wide angle, which is not preferable.

The projection screen of the present invention must have a white light reflection brightness of 10% or more and a half brightness angle of the reflection brightness of 30 degrees or more. These characteristics are those of the mat layer (1). It is obtained by adjusting the surface unevenness of the metal thin film layer (2) due to the uneven surface and the light reflection characteristics of the metal thin film layer (2). For example, the uneven surface of the mat layer (1) can be adjusted by a combination of the average particle size and amount of the organic spherical filler, and the reflection characteristic of the metal thin film layer (2) can be adjusted by a combination of the metal type and the layer thickness. It can be carried out.

The total thickness of the projection screen is 100 to 20.
It is preferably 00 μm. This total thickness is 100μ
If it is less than m, it is difficult to maintain the flatness of the screen, while if it exceeds 2000 μm, it is difficult to adopt a winding method and it is disadvantageous in terms of cost, which is not preferable. Here, the total thickness is the sum of the thickness of the plastic film substrate, the thickness of the mat layer, the thickness of the metal thin film layer, and the thickness of the protective layer.

From the viewpoint of mechanical strength and cost, the projection screen has, for example, a polyester film having a thickness of 12 to 200 μm, a mat layer, a metal vapor deposition layer, and a protective layer, which are sequentially laminated on one surface of the polyester film, and then polychlorinated on the back surface of the polyester film. It is preferable to manufacture it by a method of forming a screen having a total thickness of 100 to 2000 μm by laminating another plastic film such as vinyl.

Since the surface of the projection screen of the present invention has unevenness with a gentle inclination, and the size and number of unevenness are uniform, the specularly reflected light has a spread and the reflected light has a hem. It forms a reflective surface that gives a light curve. Therefore, a projection screen having a reflection function with a large amount of reflected light (high brightness) and a small directivity (wide angle) is provided. Moreover, the screen is made of a plastic film as a base material and coated with a resin, and can be used as a screen of a winding system.

[0032]

The present invention will be described in more detail with reference to the following examples. The reflection characteristics and scratch resistance of the projection screen were evaluated by the following methods.

1. Reflection characteristics Reflected brightness is measured by Murakami Color Research Institute's GONIOPHOTO
It was performed using METER GP-IR. JIS for measurement
According to Z-8741 (1959), the reflection brightness GS (4
5 °) was calculated from the following equation.

[0034]

GS (45 °) = (ρ _S / ρ ₀ ) × 100 (%) where ρ _S is the brightness of the sample and ρ ₀ is the brightness of the film without the matte layer provided with the metal vapor deposition layer. Indicates.

Further, the scattering property of the reflected light is obtained by connecting the points showing the half of the peak value of the reflected brightness obtained by the above method,
The angle φ _1/2 (degree) is shown as the half value. A halogen lamp of 12 V and 50 W was used as a light source, and a slit of 10 m / mφ was used on both the light source side and the light receiving side.

2. Scratch resistance The scratch resistance was evaluated using a Gakken abrasion tester. Samples and non-woven fabrics (made by Asahi Kasei Corporation: Bencott M)
-2) stacking two sheets with a load of 600 g (contact area 22 m / m ×
After rubbing 10 times at 20 m / m 2), it was judged by the degree of scratching. <Judgment> ◎: No change in appearance ○: Slightly observed after rubbing △: Light scratches are observed ×: Strong scratches are observed

[0037]

Examples 1 to 6 and Comparative Examples 1 to 6 Copolymerized polyester resin (manufactured by Toyobo Co., Ltd .: trade name Byron 200) in a methyl ethyl ketone / cyclohexanone (1/1) 30% solution, the average particle size shown in Table 1 The spherical filler of benzoguanamine-formaldehyde condensate having a diameter was added at the ratio (solid content) shown in Table 1, and the coating material was dispersed and prepared by a sand mill.

This coating was applied to a commercially available transparent / smooth 50 μm
A polyethylene terephthalate film having a thickness was uniformly coated with a reverse coater so that the coating thickness shown in Table 1 (thickness after drying) was obtained.

Next, Al (aluminum) was vacuum-deposited to a thickness of 50 nm on the coated surface to form a reflective surface. Further, a 20% methyl ethyl ketone / cyclohexanone (1/1) 20% solution of copolyester resin (product of Toyobo Co., Ltd .: Byron 200) and nitrocellulose (solid content ratio 90/10) on the vapor-deposited surface has a thickness of 3 μm after drying. Was evenly coated with a reverse coater.

Then, the polyethylene terephthalate film-based reflection sheet prepared above was bonded to a 500 μm thick black vinyl chloride sheet using a commercially available urethane adhesive to obtain a projection screen.

Table 1 shows the results of examining the reflection performance of this projection screen.

[0042]

[Table 1]

[0043]

Examples 7 to 9 and Comparative Examples 7 to 8 A 30% methyl ethyl ketone / cyclohexanone (1/1) solution of a copolyester resin (manufactured by Toyobo Co., Ltd .: Byron 200) was added to a solution of benzoguanamine. Spherical filler of formaldehyde condensate was added at a solid content ratio of 3/1 and dispersed and prepared by a sand mill.

This paint was applied to a commercially available transparent / smooth 50 μm
A polyethylene terephthalate film having a thickness was uniformly coated with a reverse coater so that the thickness after drying was 8 μm. Next, apply 100 (Al) aluminum to the coated surface.
It was vacuum-deposited to a thickness of nm to form a reflecting surface. Furthermore, a copolyester resin (manufactured by Toyobo Co., Ltd .: Byron 200) and nitrocellulose (solid content ratio 90/1) are deposited on the vapor deposition surface.
0) methyl ethyl ketone / cyclohexanone (1 /
1) A 20% solution was uniformly applied with a reverse coater so that the thickness after drying would be the value shown in Table 2.

Then, the reflection sheet of the polyethylene terephthalate film base material prepared above was bonded to a 500 μm thick black vinyl chloride sheet using a commercially available urethane adhesive to obtain a projection screen.

Table 2 shows the results of examining the reflection performance and scratch resistance of this projection screen.

[0047]

[Table 2]

[0048]

According to the present invention, a projection screen which has a high reflection extreme and gives a clear image even in daylight, has a small light directivity and can obtain a clear image even in a wide angle, and can be rolled up. Can be provided.

Claims (6)

[Claims] 1. (1) on a plastic film substrate
It has a structure in which a mat layer mainly composed of an organic spherical filler and a binder (binder), (2) a metal thin film layer, and (3) a protective layer are sequentially laminated, and the reflection brightness of white light is 10% or more, A projection screen having a half value angle of reflected brightness of 30 degrees or more. 2. The projection screen according to claim 1, wherein the surface of the plastic film substrate on which the mat layer is laminated is made of a polyester film. 3. A projection according to claim 1, wherein the weight ratio of the organic spherical filler to the binder (binder) is 1: 6 to 1: 1 and the average particle diameter of the organic spherical filler is 1 to 12 μm. screen. 4. The projection screen according to claim 3, wherein the matte layer has a thickness of 0.5 to 3.0 times the average particle diameter of the organic spherical filler. 5. The projection screen according to claim 1, wherein the metal thin film layer is an aluminum vapor deposition layer having a thickness of 20 to 200 nm. 6. The projection screen according to claim 1, wherein the thickness of the protective layer is in the range of 1 μm to 1.0 times the average particle size of the organic spherical filler contained in the mat layer.