JP3001731B2 - Projection 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 projection screen, and more particularly, to a projection screen which has high reflection brightness of light, has low directivity, and can be wound up when not in use.

[0002]

2. Description of the Related Art Projection screens have been widely used in offices and the like as screens for overhead projectors. Recently, projection TVs have become widespread as TV screens have become larger.
Projection screens are also being used in homes.

[0003] However, in the conventional combination of a projector and a projection screen, the brightness is insufficient, so that it is necessary to darken the room with a curtain or the like. Therefore, there is a demand for improvement in the brightness of the projection screen (high-brightness screen) as well as improvement in the brightness of the projector.

[0004] Also, with an overhead projector,
Recently, an apparatus capable of directly photographing an original such as paper without using a dedicated transparent film has been developed.In the case of this apparatus, since the reflected light is used, the brightness of the projector is insufficient. You need a high brightness projection screen.

Various types of projection screens have hitherto been used, and a roll-up type screen is mainly coated with a bead type in which fine glass spheres are provided on the screen surface or a pearl pigment ink. Clear type is used. However, the brightness is not enough.

As the high-brightness type, an aluminum foil or an aluminum vapor-deposited sheet is used and a curved screen is used. In this case, however, it is difficult to use a roll-up type, and it is mainly a fixed type. used. In the case of the fixed type, although it has high luminance, it has a disadvantage that an installation place is required. For this reason, especially for home use, there is a demand for a roll-up type high-intensity screen.

Further, in the case of a projection screen for a projection television, 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, a reflection screen having a high reflection luminance and a small light directivity is demanded.

[0008]

The inventor of the present invention has intensively studied to develop a projection screen satisfying such demands, and as a result, the present invention has been achieved.

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

[0010]

An object of the present invention, in order to solve the problems], according to the present invention, Ri primarily <br/> name on a plastic film substrate (1) organic spherical fillers and a binder (binding agent), the Organic spherical filler and binder (binder)
Is from 1: 6 to 1: 1 and the organic spherical particles are
Mat layer having an average particle size of 1 to 12 μm ,
(2) It has a structure in which a metal thin film layer and (3) a protective layer are sequentially laminated, and the reflection luminance of white light is 10% or more, and the half-value angle of the reflection luminance is 30 degrees or more. Achieved by the featured projection screen.

The plastic film substrate in the present invention is particularly preferably a polyester film, but may be a film made of another resin such as polystyrene, polyvinyl chloride, polymethyl acrylate, polycarbonate, acetate resin, polysulfone and the like. . 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 an advantage that its surface is very smooth, and it is not necessary to consider the surface unevenness of the film itself when a surface is formed by coating a paint thereon. It has the advantage of good heat resistance and excellent mechanical performance.

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

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

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

The sphericity of the organic spherical filler is 0.
Eight or more spherical fillers are preferable. For example, benzoguanamine resin (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) (Tospearl), etc.).

Here, the degree of vacuum of the spherical filler is represented by the ratio of the minor axis to the major axis of the particles (minor axis / major axis). Can be measured from the image obtained.

The average particle size of the organic spherical filler is 1 to 12
μm, and more preferably 2 to 10 μm. When the average particle size is less than 1 μm, the surface of the mat layer becomes smooth and the luminance increases, but the directivity is large.
A clear image cannot be obtained at a wide angle, while 12 μm
When the value exceeds, the luminance becomes extremely low when the directivity is suppressed, so that high luminance 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 and the like can be used. In particular, what is 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 does not drop. Since a metal is vacuum-deposited on the surface, particularly aluminum, as a post-process, a binder having heat resistance is preferable.

The ratio of the filler to the binder is an important factor from the viewpoint of the surface design of the coating film. In particular, in the case of a binder which has no projection performance in the binder itself and has a flat coating film forming ability, only the presence of the filler is a factor for forming fine irregularities. If the proportion of the filler is too small, the projections are only scattered in some places on the flat portion of the application surface, and it is impossible to provide a preferable reflection performance. On the other hand, when the proportion of the filler is too high and exceeds the critical pigment volume concentration (CPVC), the binder penetrates into the overlap of the fillers, so that the concave portions of the projections are not flattened, and the amount of reflected light rapidly decreases. . Therefore, the ratio (weight ratio) of the filler to the binder has a suitable range, that is, 1/6 to 1/1. When the ratio of the filler and the binder exceeds 1/1, the luminance is significantly reduced,
On the other hand, when it is less than 1/6, the luminance 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 in the preparation of the coating solution for the mat layer is not particularly limited as long as it does not substantially attack the film and the organic spherical filler, and a 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 filler and binder concentration 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 size of the organic particulate filler.
A thickness of 5 to 3.0 times is preferred. When the thickness is less than 0.5 times the average particle size, the brightness decreases and high brightness and low directivity cannot be simultaneously satisfied. On the other hand, when the thickness exceeds 3.0 times, the brightness increases but the directivity increases. Too strong and unfavorable.

The coating of the mat layer coating liquid onto the plastic film can be carried out by various methods, for example, by a Meyer bar coat, a reverse coat, a kiss roll coat, a gravure coat, or the like.

In the present invention, the metal thin film layer (2) is formed on the mat layer (1), but there is no particular limitation on the formation method, and a physical vapor deposition method, for example, a vacuum vapor deposition method, a sputtering method, an ion plating method, or the like. Method or the like can be used. As the metal, for example, aluminum, chromium, silver and the like can be mentioned, 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 evaporation of aluminum.

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

In the present invention, the protective layer (3) is formed on the metal thin film layer (2), but a layer conventionally used as a protective layer for the metal thin film layer can be applied. For example, it can be formed using an acrylic resin, a polyester resin, nitrocellulose, a melamine resin, an 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 unevenness of the mat layer. In this respect, the protective layer has a thickness of 1 μm.
The average particle diameter of the organic spherical filler contained in the mat layer is preferably up to 1.0 times the average particle diameter. The upper limit of the thickness is more preferably 0.8 times the average particle size. When the thickness is less than 1 μm, the abrasion resistance, durability and the like are reduced, and the function as a protective layer is insufficient. On the other hand, when the average particle size of the filler exceeds 1.0 times,
Although the surface is flattened and the brightness is increased, the directivity is increased and it is difficult to use the device at a wide angle, which is not preferable.

The projection screen of the present invention needs to have a reflection luminance of white light of 10% or more and a half-value angle of the reflection luminance of 30 ° or more. These characteristics depend on the matte layer (1). It is obtained by adjusting the surface unevenness of the metal thin film layer (2) by 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 the amount of the organic spherical filler, and the reflection characteristics of the metal thin film layer (2) can be adjusted by the combination of the type of the metal 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. 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.

In view of mechanical strength and cost, a projection screen is formed by sequentially laminating a mat layer, a metal deposition layer and a protective layer on one side of a polyester film having a thickness of 12 to 200 μm, and then forming a polychlorinated film on the back side of the polyester film. It is preferable to produce the screen by laminating another plastic film such as vinyl to form a screen having a total thickness of 100 to 2000 μm.

The projection screen of the present invention has irregularities with a gentle inclination on the surface, and the size and number of the irregularities are uniform. A reflecting surface giving a light curve is formed. 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. In addition, the screen is made of a plastic film as a base material and is coated with a resin, and can be used as a screen of a winding type.

[0032]

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

1. Reflection characteristics Reflection luminance is measured by the GNIOPHOTO of Murakami Color Research Laboratory Co., Ltd.
This was performed using METER GP-IR. In the measurement, JIS
According to Z-8741 (1959), the reflection luminance GS (4
5 °) was determined by the following equation.

[0034]

GS (45 °) = (ρ _s / ρ ₀ ) × 100 (%) where ρ _s is the luminance of the sample, and ρ ₀ is the luminance of a film without a mat layer provided with a metal deposition layer. Is shown.

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

2. Scratch resistance The scuff resistance was evaluated using a Gakken abrasion tester. The evaluation was performed on a sample and a nonwoven fabric (manufactured by Asahi Kasei Corporation: Bencott M)
-3) A stack of 2 sheets was loaded with a load of 600 g (contact area 22 m / m x
After rubbing 10 reciprocations at 20 m / m 2), the degree of scratching was evaluated. <Judgment> ：: No change in appearance ○: Slightly observed after rubbing ：: Thin scratch observed ×: Strong scratch observed

[0037]

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

This paint is coated with a commercially available transparent and smooth 50 μm
The film was uniformly coated on a polyethylene terephthalate film having a thickness with a reverse coater so as to have a coating thickness (thickness after drying) shown in Table 1.

Next, Al (aluminum) was vacuum-deposited to a thickness of 50 nm on the application surface to form a reflection surface. Further, a 20% solution of a copolymerized polyester resin (manufactured by Toyobo Co., Ltd .: Byron 200) and nitrocellulose (solid content ratio: 90/10) in methyl ethyl ketone / cyclohexanone (1/1) was dried on the deposition surface to a thickness of 3 μm. Was applied uniformly with a reverse coater.

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

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

[0042]

[Table 1]

[0043]

Examples 7 to 9 and Comparative Examples 7 to 8 A 30% solution of a copolymerized polyester resin (manufactured by Toyobo Co., Ltd., trade name: Byron 200) in methyl ethyl ketone / cyclohexanone (1/1) was prepared by adding a benzoguanamine having an average particle size of 5 μm. A spherical filler of formaldehyde condensate was added at a solid content ratio of 3/1, and the mixture was dispersed and blended with a sand mill.

This paint is coated with a commercially available transparent and smooth 50 μm
It was evenly applied to a polyethylene terephthalate film having a thickness by a reverse coater so that the thickness after drying was 8 μm. Then, Al (aluminum) is applied to the coating surface by 100
A reflective surface was formed by vacuum evaporation to a thickness of nm. Further, a copolyester resin (manufactured by Toyobo Co., Ltd .: Byron 200) and nitrocellulose (solid ratio: 90/1) are formed on the deposition surface.
0) methyl ethyl ketone / cyclohexanone (1 /
1) A 20% solution was uniformly coated with a reverse coater so that the thickness after drying became the value shown in Table 2.

Then, the reflection sheet of the polyethylene terephthalate film substrate prepared above was bonded to a black vinyl chloride sheet having a thickness of 500 μm using a commercially available urethane-based 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 degree of reflection, provides a clear image even in daylight, has a small light directivity and can obtain a clear image even at a wide angle, and can be wound up. Can be provided.

Claims (5)

(57) [Claims] 1. A plastic film substrate having (1)
Organic spherical fillers and a binder Ri mainly Na from (binder), organic matter spherical filler and the binder (binding
Agent) in a weight ratio of 1: 6 to 1: 1 and the organic spheres
Mat layer having an average particle size of the filler in the range of 1 to 12 μm ,
(2) It has a structure in which a metal thin film layer and (3) a protective layer are sequentially laminated, and the reflection luminance of white light is 10% or more, and the half-value angle of the reflection luminance is 30 degrees or more. Characteristic projection screen. 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. Wherein the thickness of the mat layer, projection screen according to claim 1, wherein 0.5 to 3.0 times the average particle diameter of the organic spherical fillers. 4. The projection screen according to claim 1, wherein the metal thin film layer is an aluminum vapor-deposited layer having a thickness of 20 to 200 nm. 5. The projection screen according to claim 1, wherein the thickness of the protective layer ranges from 1 μm to 1.0 times the average particle diameter of the organic spherical filler contained in the mat layer.