JPS6239831A - Manufacture of transmission type projection screen - Google Patents

Abstract

PURPOSE:To obtain the projection screen of a large area, having a sufficient light shielding effect and a high contrast, by forming a matrix by making a resin film layer stuck closely to the upper face of spherical beads arranged adjacently on a plane, and executing the forming by using a mold made from this matrix. CONSTITUTION:Spherical beads 4 are arranged adjacently on the plane of the inside of a frame body 9 and a resin film 8 is installed so as to cover the upper edge part 11 of the frame body 9 and the spherical beads 4. Subsequently, the inside of the frame body 9 is brought to a pressure reduction by a vacuum pump, etc., from the aperture 10 of the frame body 9, and the resin film layer 8 is made to stick closely to the upper face of the spherical beads 4. In this case, the resin film 8 is heated by a hot air, etc., softened, and also hardened. Fro the surface of the spherical bead group 4 formed integrally by the resin film layer 8 obtained in this way, molding is executed by using a plaster silicone resin, etc., two pieces of the same split molds 12 are made and a coupled mold is formed. By using this mold, the projection screen of a large area can be obtained easily.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a transmissive projection screen used in a transmissive projection device such as a projection color television device, a projection display device, and an enlarged projector. Relating to a manufacturing method. More specifically, the present invention relates to a method for manufacturing a transmission type projection screen that can easily produce a large-area projection screen.

(Prior Art) In a transmissive projection apparatus, the quality of an image observed through a projection screen is largely influenced by the characteristics of the transmissive projection screen, and therefore various screens have been proposed in the past.

For example, as shown in FIG. 1, a two-sided lenticular lens structure in which a plurality of columnar convex lenses are formed in parallel in a striped pattern on the observation surface of a transparent plate is known.

In such a transmission type projection screen 1, light is only blocked by uniformly darkening 54 parts from the center to the edges in a stripe shape, and only the parts through which light passes are blocked. As a result, light from behind the viewer is reflected on the screen, making it difficult to obtain contrast in the image.

On the other hand, a mosaic transmission type projection screen which is an assembly of micro spherical lenses as described in Japanese Patent Application Laid-Open No. 57-81255, for example, a projection screen 3 as shown in FIGS. 2(a) and 2(b). Although there is an advantage in that it is possible to install an ultraviolet lamp in the light source device and use a photoengraving method to leave a light-transmitting area and block out all other areas, it is not possible to use a large-area projection screen. The drawback was that it was extremely troublesome to obtain. In other words, such a projection screen 3 is made by using a drill rod with a tip such that the hole shape becomes the curved surface shape of a hemispherical lens when cut. It is manufactured by cutting a shaped depression into a mold, placing two molds facing each other, and molding transparent resin or glass. In this method, it is necessary to make a mold by cutting out each hemispherical depression with a diameter of 1 to 21 times, and it is virtually impossible to make a large-area mold to obtain a large-area projection screen. Industrially, a cumbersome method has been used in which projection screens of several cm square are made and then joined together to obtain a large-area projection screen.

(Problems to be Solved by the Invention) The present invention improves various drawbacks of conventional projection screens, and provides a mosaic transmission type projection screen that can easily obtain a large-area projection screen with sufficient light shielding effect and high contrast. The present invention provides a method for manufacturing.

[Structure of the invention]

(Further Means for Solving the Problems) The present invention involves molding using a mold made of a resin film layer closely attached to the upper surface of spherical beads arranged closely on a plane as a matrix. This is a manufacturing method for a transparent projection screen.

Hereinafter, nine aspects of the present invention will be explained using the drawings.

FIG. 3 is a partial sectional view of a transmissive projection screen according to the present invention. As shown in Fig. 3, the corresponding front and back lens curved surfaces constitute a part of one sphere, and in order to increase the pixel density and to form one continuous projection screen, Two adjacent spheres are interpenetrating each other.

The material and diameter of the spherical beads used in the present invention may be the same or different.

Spherical beads can be made of glass or plastic.

Examples include metals such as iron and styrene, and ceramics, and may be hollow. The diameter of the spherical beads is determined by the desired pixel density, that is, the size of each lens. When it is desired to uniform the appearance of spherical beads, they can be classified using a standard sieve.

It is sufficient that the spherical beads are arranged closely on a plane.

The arrangement may be random or regular,
Further, the spherical beads may be arranged in contact with each other or may be arranged apart from each other. In order to increase the pixel density, it is preferable that the nine spherical beads are arranged in contact with each other, and it is particularly preferable that the nine spherical beads are arranged in close-packed form.

FIGS. 4(a) and 4(b) are partial cross-sectional views showing a state in which spherical beads 4 having the same diameter are arranged in contact with each other on a plane. If the diameters of the spherical beads 4 are the same, the fourth
By arranging the beads as shown in Figure (a), it is easy to arrange the spherical beads because they have the same diameter. ■The pixel density can be maximized because it is in the form of close packing. ■Can be aligned parallel to the TV image raster. (2) This method is most preferable in that it is easy to create a pattern original when etching a perforated plate for arranging spherical beads, which will be described later.

There is no particular restriction on the method of arranging the spherical beads 4 in close proximity on a plane, and any method may be used.

For example, in practical use, as shown in FIG. 5 as a partial cross-sectional view, holes are provided in the desired spherical bead arrangement so that a portion of each spherical bead 4 slightly protrudes below. There is a method of preparing a perforated plate 6 as shown in a partial perspective view, keeping the perforations 4Fi6 horizontal, sprinkling one spherical bead 4 without a swirl layer, and then removing excess spherical beads 4. At this time, in order to arrange the beads as shown in FIG.
must be the same as the diameter of In addition, at this time, as shown in a partial cross-sectional view in FIG. 7, if an adhesive sheet 7 is pasted on the back side of the porous plate 6, the spherical beads 4 are fixed.
This makes it easier to remove excess spherical beads. The material of the porous plate 6 for arranging the spherical beads 4 is not particularly limited, and metal plates such as brass, copper, stainless steel, iron, and nickel, and plastic plates can be used.

A metal plate or a plastic plate is used when the holes are drilled, and a metal plate is used when the holes are etched. There are no particular restrictions on the method of perforation (there are drilling methods and etching methods, but the etching method is preferred from the viewpoint of workability.Also, there is no particular restriction on the thickness of the perforated plate, but depending on the spherical shape used) The diameter is preferably about 1/2 to 1/4 of the radius of the beads.For example, the diameter of the spherical beads used in the present invention is usually about 1 to 2 mm.
A perforated plate with a thickness of 0.2 to 0.5 fins is used.

Next, we will discuss the production of perforated plates by etching.

After thoroughly smoothing a metal plate such as a stainless steel plate with a thickness of 0.2 to 0.5 fins, use an aqueous solution of a mixture of polyvinyl alcohol and dichromate as a photosensitive liquid, and apply this to a dry film thickness of 5. Coat on both sides of the metal plate to a thickness of ~10 μm and dry in a dark place. A positive film with black openings corresponding to the desired holes is brought into close contact with both or one side of a coated metal plate, irradiated with ultraviolet rays of sufficient intensity to harden the coating, and developed with water. At this time, when etching is performed from only one side of the three sides, a positive film is brought into close contact with one side, and the entire surface is exposed without bringing the positive film into close contact with the other one side. When etching is performed from nine sides, positive films are brought into close contact with both sides so that the positions of the patterns on both sides correspond accurately, and R light is applied. In this way, after exposure and development, etching is performed with an etching solution such as a saturated aqueous solution of ferric chloride, and after pores of the desired size are formed, washing is performed with water. Boil it and expose the hardened part to light! I- is removed to obtain a perforated plate.

On the upper surface of the spherical beads 4 arranged closely on a plane,
Eight layers of resin film are adhered. One gap 5 is formed between three adjacent spherical beads 4 in FIG. 4(a), and one gap 5 is formed between four adjacent spherical beads 4 in FIG. 4(b). In this case, it is impossible to obtain a continuous projection screen because adjacent beads do not form a projection screen, but beads 4 with a radius r are arranged on a flat surface, and the upper surface has a thickness [
If 8 layers of resin film are closely attached, spherical beads of radius r + t will be arranged in a shape that interpenetrates with each other.
FIG. 8(a) is a partial cross-sectional view showing a state in which spherical beads 4 having a radius r are closely arranged on a flat surface, and a partial cross-sectional view showing a state in which eight layers of resin film having a thickness t are adhered to the upper surface thereof. This is clear from FIG. 8(b). Figure 4(a)
And in (b), when the radius of the two spherical beads 4 is r, the distance l from the center of the bead to the center of the gap is.

x=2nr/3..., Fig. 4(a) J"3 r >1≧J'72r ---Fig. 4(b)
The minimum thickness t of the resin film 8 that forms the Ji side and covers the gap 5 is as follows.

t-(2JE/3-1> r ・-m4 Figure (a) (row-
1) r>t≧(row-1) r...Fig. 4(b), and by using the resin film 8 having a thickness of t or more, it is possible to reach the center of each gap 5. .

As mentioned above, it is sufficient that the two spherical beads are arranged close to each other, and one spherical bead may be spaced apart from each other.

Also in this case, the thickness t of the resin film 8 used is 1
The distance may be greater than or equal to the distance from the center of the gap to the center of the spherical bead divided by the radius r of the spherical bead.

The resin film 8 used in the present invention may be of any material as long as it can maintain its film shape when it is brought into close contact with it, but it must be hard enough to come into close contact with the top surface of the spherical beads only when it is heated or an external force is applied. It is preferable that
Its material is polyethylene.

There are thermoplastic resins such as polystyrene, thermosetting resins, radiation-curable resins that are cured by radiation such as electron beams and ultraviolet rays, and resins that dry by solvent volatilization. As a film made of radioactive curable resin, pudding = 9-1. For wiring boards! A dry film commercially available as /Cyst can be suitably used.

Any method may be used to bring the 8 layers of resin film into close contact with the two surfaces of the spherical beads 4 arranged close to each other on a plane.

For example, eight layers of resin film are brought into close contact with the surface of the spherical beads 4-1 by the steps shown in cross-sectional views in FIGS. 9(a) to 9(C). That is, one spherical bead 4 is arranged close to the plane -A inside the frame 9 by the method shown in FIG. 7 or another method (FIG. 9(a)).

Next, the resin film 8 is installed so as to cover the upper edge 11 of the frame body 9 and the spherical piece 4 (FIG. 9(b)).

Next, the pressure inside the frame body 9 is reduced using a vacuum pump or the like from the opening 1-1 part 10 of the frame body 9, and 1 spherical beads 4-
The eight layers of fat film are brought into close contact (Fig. 9(C)). At this time, the resin film Jx 8 can also be heated with hot air or the like to soften it. Furthermore, when a thermosetting resin film or a radiation curable resin film is used as the resin film 8, curing conditions are maintained.

Obtained in this way. 1 plaster from the surface of 4 groups of spherical beads integrated with 8 layers of resin film.

A mold is made using an impression material such as silicone resin, and based on this, two identical split molds 12 are made and these are combined into the first mold.
It can be made into a mold as shown as a cross-sectional view in FIG.

Further, on the surface opposite to the 8 resin film layers of the 4 groups of spherical beads integrated by the 8 resin film layers, as shown in FIG.
A further 8 layers of resin film are adhered through the same steps as those shown in a) to (C), and a mold is made from both the front and back sides of the obtained four groups of spherical beads using an impression material, and based on this, both the front and back sides are Make one split mold 12 from each,
These can also be combined into a mold as shown as a sectional view in FIG. The method of making the mold is the usual method. In order to obtain the desired thickness of the eight layers of resin film, the steps shown in FIGS. 9(a) to (C) can be repeated.

The material of the mold is determined by the material of the projection screen and the molding method, and is appropriately selected from metal, plastic, glass, etc. For example, when obtaining a projection screen by injection molding a colorless and transparent thermoplastic resin such as polymethyl methacrylate, polyester, or polycarbonate, the mold is made of unsaturated polyester.

A mold is used to obtain a projection screen by casting a reactive resin that is liquid at room temperature, such as a two-component curing epoxy resin.

Plastic molds or glass molds are used, respectively. In addition, there are 1 materials for the projection screen.
Glass such as quartz glass can be used as an example.

The observation surface of the projection screen obtained in this manner can be subjected to a light-shielding treatment on the portions through which no light passes, in order to increase the contrast. There are two methods for light shielding treatment, for example, Japanese Patent Application No. 58-24472! l.

The method described in Japanese Patent Application No. 58-244730 can be used.

According to the manufacturing method of the present invention, it is possible to make a large-area projection screen from a set of molds, but similarly to the conventional manufacturing method, it is possible to make a small-area projection screen in the required amount and join them together. It is also possible to create a projection screen of any desired size. As the adhesive used for bonding, a black opaque adhesive 1, such as a two-component curing epoxy adhesive mixed with carbon blank, may be used.

It is possible to prevent light from leaking from the joint and make the joint less noticeable.

(Example) A hole with a diameter of 0 was placed on the entire surface of a 0.2-thick stainless steel plate.
．． 85mm, the distance between the centers of two adjacent holes is 1±0.
05m, and the arrangement of one spherical bead is shown in Figure 4 (a).
so that it has a close-packed shape as shown in .

Holes were made by etching. Apply an adhesive sheet to the entire surface of one side of the obtained perforated plate, hold the perforated plate horizontally with the other side facing up, sprinkle stainless steel beads with a diameter of 1 ± 0.05, and fill all the holes with beads. Fixed.

After removing excess beads, the perforated plate with the beads fixed thereon was placed in a frame as shown in Figure 9(a) with the bead side facing upward, and the bead side and frame were covered with a 100 μm thick polyethylene film. The upper edge of the body was covered, and while blowing hot air at 180° C. onto the polyethylene film, the pressure inside the frame was reduced to bring the polyethylene film into close contact with the upper surface of the beads. From the film surface of the bead group integrated with the polyethylene film, a two-component cold-vulcanized silicone rubber impression material was molded in a conventional manner to make two split molds. Using the obtained mold, polymethyl methacrylate (13-metal) was injection molded to obtain a projection screen.

(Effects of the Invention) According to the present invention, the light shielding effect is sufficient and the contrast is high.
It has become possible to easily manufacture large-area mosaic-like projection screens that have no joints and no light leakage.

[Brief explanation of drawings]

1, 2(a) and 2(b) are partial perspective views showing conventional transmission type projection screens, respectively. FIG. 3 to FIG. 1O are views each showing an embodiment of the present invention, and FIGS. 3, 5, 7, 8 (a) and 8 (b) are partial cross-sectional views, and FIG. Figure 9 (a) to (C
) and FIG. 10 are sectional views, respectively. FIGS. 4(a) and 4(b) are partial plan views, respectively. FIG. 6 is a partial perspective view. The symbols in the figure are as follows. 1... Lenticular transmission type projection screen. 2... Light shielding processing section. 3...Mosaic transmission type projection screen. 4... Spherical beads. 5... Gap. 6... Porous plate. 7... Adhesive sheet. 8...Resin film. 9...Frame body. 10...Opening. 11... Upper edge. 12...split type.

Claims (1)

[Claims] 1. A method for manufacturing a transmission projection screen, which comprises molding using a mold made of a resin film layer closely attached to the upper surface of spherical beads arranged close to each other on a plane.