JPH0915728A - Projecting screen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability and contamination resistance of a projecting screen which has high luminance and excellent diffusion performance and affords videos having high image quality by providing a plastic base material sheet with a coating film of a coating material contg. powder of calcite. SOLUTION: The sheet 1 of the transparent plastic is used as the base material sheet and the sheet 1 is provided with the coating film 2 of the coating material contg. the powder 3 of the calcite. In such a case, the arbitrary plastic sheet 1 is used for the base material sheet and the sheet having the excellent solvent resistance and dimensional stability is more preferable. The sheets formed of polyester, such as triacetyl cellulose, polyethylene terephthalate and polyethylene naphthalate, are the representative examples thereof. The coating material having the powder 3 of the calcite consists of a suitable vehicle, such as melamine resin and urethane resin, and a suitable solvent meeting the vehicle. Further, the powder 3 of the calcite has adequately a grain size of 2 to 20μm and the grain size distribution thereof is preferably as narrow as possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection screen for receiving an image projected from a projection device, and more particularly to a projection screen for a liquid crystal projector.

[0002]

2. Description of the Related Art A diffuse transmission screen is one of the devices that allow a large number of viewers to see an image on a television, for example. The diffuse transmission screen is
The light incident from one surface of the screen is slightly diffused and transmitted to the other surface so that the image on the screen can be seen even in a region outside the passage of the light that travels straight. Many screens of this type are provided with a diffusion property by matting the surface of a plastic sheet.

On the other hand, a reflection type screen having a white surface is used for the projection of slides and movies.

In recent years, a liquid crystal projector has appeared and is becoming popular as a means for displaying a clear image on a large screen. Including those used for LCD projectors,
The projection screen has high brightness, that is, the transmissive type has a high light transmittance, the reflective type has a high reflectance, and the diffusing performance is good, that is, the light is uniformly diffused in a desired direction. Is required to be able to do.

As a screen that meets this demand, there is known a screen in which an adhesive is applied to a sheet of plastic or the like and glass beads having a small diameter are arranged on the sheet so as to be closely packed. However, because of its structure, this screen is
The beads are likely to fall off, and dust is likely to collect on the surface, making them impractical.

In particular, as a reflection type screen, a gold pigment, a silver pigment or a pearl pigment is mixed on the vinyl chloride resin layer of an ordinary vinyl wallpaper as described in JP-B-63-67474. A vinyl wallpaper coated with vinyl chloride and having a high surface reflectance was also used by adhering it to the wall surface, but sufficient reflectance and diffusing performance were not obtained.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is a projection screen suitable for use in the projection of images represented by liquid crystal projectors, which gives high-quality images with high brightness and excellent diffusion performance. To provide a durable and stain resistant product.

[0008]

The projection screen of the present invention comprises a plastic substrate sheet and a coating film of paint containing calcite powder.

Specific examples include a transmission type and a reflection type. In the transmission type, as shown in FIG. 1, a transparent plastic sheet (1) is used as a base sheet, and calcite is used. A coating film (2) of a paint containing the powder (3) is provided.

In the reflective type, as shown in FIG. 2, a coating film (2) of a paint containing calcite powder is provided on a plastic base sheet (1) on a plate or sheet (4). It is made by stacking things. You may use a light-reflective thing as a board or a sheet, and laminate | stack the above-mentioned transmission type projection screen on it. The plate or sheet (4) which is light reflective is, for example, a white vinyl wallpaper having a polyvinyl chloride layer mixed with a titanium dioxide pigment,
A metal foil or a plastic obtained by vapor deposition or plating of a metal may be used.

In FIGS. 1 and 2, (6) is a projector.

As the base material sheet, any plastic sheet can be used, but those having excellent heat resistance, solvent resistance and dimensional stability are preferable, and polyesters such as triacetyl cellulose, polyethylene terephthalate and polyethylene naphthalate are preferable. A sheet made of is a typical example.

The coating material containing the calcite powder is composed of an appropriate vehicle such as melamine resin and urethane resin, and an appropriate solvent selected accordingly. Needless to say,
The higher the proportion of calcite powder in the paint, the better,
If the proportion of the vehicle is too low, it becomes difficult to form a coating film on the substrate sheet, so the composition of the coating composition is 10 to 100 parts by weight of the vehicle, particularly 10 to 5 parts by weight based on 100 parts by weight of the calcite powder.
A range of 0 parts by weight is preferred.

The calcite powder has an average particle size of 2 to 20 μm.
It is preferable that the particle size distribution is as narrow as possible. For example, when the average particle size is 5 μm, 8
The particle size distribution is such that 0% by weight or more falls within the range of 3 to 7 μm.

The coating material is applied to the base sheet by a known means such as roll coating, reverse coating, comma coating and die coating. Although the thickness of the coating film depends on the particle size of the calcite powder, it suffices if it is 10 μm or more in the dry state, and generally, a range up to 30 μm, for example, 15 μm is suitable.

As a modification of the above-mentioned transmission type projection screen, it is also possible to provide a large number of small holes so that the projection screen has a provisional function and the back can be seen. Such a method has already been proposed and disclosed by the applicant (Japanese Utility Model Publication No. 1-157333). The small holes provided in the screen are as described in the specification of the above application, for example, circular holes having a diameter of 0.1 to several mm,
It may be provided so that the aperture ratio occupying the sheet area is in the range of 5 to 70%.

The projection screen of the present invention is preferably provided with a flexible or rigid backing material by means of adhesion or the like, depending on the intended use, for convenience of handling. The backing material is, of course, laminated on the back surface of the screen, that is, on the surface of the base sheet opposite to the surface on which the coating is formed. As a material for the backing material, a glass plate or a transparent plastic sheet or plate in a transmission type projection screen is preferable. When using a plastic plate,
For example, a transparent and high strength material such as an acrylic resin plate or a polycarbonate plate is preferable.

The projection screen of the present invention may be used by directly adhering it to the glass of a wall or a window, or may be hung in a space by providing a hanging means, or can be erected at a desired position using a stand means. You may use it.

[0019]

[Function] As the optical properties of calcite powder suggest that light incident on individual particles is less likely to be attenuated inside the particles and is emitted at a high ratio, a coating film containing calcite powder should be used. The light that is transmitted or reflected by it is highly transmissive or highly reflective and therefore the brightness of the projection screen. Diffusion in the coating film is performed uniformly in each direction. Generally, when the diffusion angle becomes wider,
Although the brightness of the projection screen is reduced and the screen becomes dark, the present invention makes it possible to see a relatively bright screen regardless of the direction from which the screen is viewed.

[0020]

【Example】

 [Example 1] Transmissive projection screen A coating material having the following composition was prepared.

Calcite powder (average particle size: 5 μm) 60 parts by weight Polyester resin (vehicle) 20 parts by weight Methyl ethyl ketone (solvent) 10 parts by weight Toluene (solvent) 10 parts by weight A transparent polyethylene terephthalate sheet having a thickness of 75 μm is used as a base material. As a sheet, the above coating material was applied thereto with a roll coater and dried to form a coating film having a thickness of 25 μm.

This sheet is attached to a transparent acrylic resin plate having a thickness of 5 mm with a transparent adhesive, and the screen size is 10
It was cut to have a size of 0 inch (diagonal length of a rectangle) to obtain a transmission type projection screen of the present invention.

For comparison, a projection screen was obtained in the same manner as above using a coating material containing calcium carbonate powder commonly used as a filler in place of the calcite powder.

Light is vertically incident on these projection screens from behind, and the light intensities in various directions are measured.
The state of transmittance and diffusion was investigated. In each case, the examples of the present invention were superior to the comparative examples.

Example 2 Reflective projection screen The following materials were kneaded and the viscosity was adjusted with mineral spirit to prepare a hiding vinyl chloride sol.

Chlorinated resin "PSC-280" (Kanegafuchi Kagaku) 100 parts by weight Calcium carbonate "Whiton-H" (Shiraishi Industry) 100 parts by weight Pigment "R-900" (DuPont) 20 parts by weight Plasticizer DOP 60 parts by weight Parts Stabilizer "AC-113" (Adeka Argus) 2.5 parts by weight Plastic film "WK-70NRD" as a base material
(Kohjin) was used to coat the above sol to a thickness of 100 μm, and the gel was placed in an atmosphere at 200 ° C. for 60 minutes.

With separately prepared aluminum flakes (70μ
m, 23 phr) of a vinyl chloride calender film was used as a reflection layer, and the above-mentioned gelled vinyl chloride coat sheet was integrated by hot pressure doubling.

Then, the transmission type projection screen produced in Example 1 was dry-laminated to obtain a wallpaper type reflection type projection screen of the present invention.

[0029]

The projection screen of the present invention can project a high-quality image on a large screen with high luminance, and there is no great difference in the brightness depending on the viewing direction of the screen. Can be used in combination with the projection means.

Since the calcite powder is dispersed in the coating film and fixed by the vehicle, there is no concern that it will fall off easily like a conventional screen with beads attached, and the surface is smooth so that it does not easily become dirty and does not become dirty. Easy to wipe.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a transmissive example of a projection screen of the present invention.

FIG. 2 is a view similar to FIG. 1 for explaining a reflection type example of the projection screen of the present invention.

[Explanation of symbols]

 1 Base Material Sheet 2 Coating Film 3 Calcite Powder 4 Light-Reflecting Sheet or Plate 6 Projector

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Mishiro 1-1-1, Ichigayakaga-cho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd.

Claims (7)

[Claims] 1. A projection screen comprising a plastic substrate sheet and a coating film of paint containing calcite powder. 2. The projection screen according to claim 1, wherein a large number of small holes are provided so that the back of the screen can be seen. 3. A projection screen comprising a transparent glass or plastic plate on which the projection screen according to claim 1 is attached. 4. A plate or sheet which reflects light.
Projection screen made by stacking the projection screens of. 5. The projection screen according to claim 1, wherein the coating material comprises 100 parts by weight of calcite powder having a particle size of 2 to 20 μm and 5 to 30 parts by weight of a vehicle. 6. The projection screen according to claim 1, further comprising a suspending means or a stand means. 7. A projection screen according to claim 1, which is used for projection by a liquid crystal projector.