JPH0437735A - Projection screen and its production - Google Patents

Abstract

PURPOSE:To reduce the loss of a light quantity and to improve the directional characteristic in a direction orthogonally crossed with the axial direction of light transmissive strand by forming fine rugged surface on the surface of a screen body formed by arranging many plastic light transmissive strands in parallel in a sheet state. CONSTITUTION:The outer surface of the adjacent light transmissive strands 10 is welded 11 and integrated, consequently it becomes like the sheet, then a projection screen is constituted. Since the rugged surface 12 is formed on at least one surface of the screen body, transmitted light is diffused in the direction orthogonally crossed with the axial direction of the strand 10,generally in a vertical direction, by the action of the surface 12, thereby improving the directional characteristic. The strand 10 is formed of plastic excellent in light transmissivity such as thermoplastic polymer, for instance, acrylic polymer, polycarbonate polymer, and polyacrylate and cross-linking hardening type polymer, for instance, cross-linking silicone polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transmissive or reflective projection screen used as a screen for a projection television, a microfilm reader, etc., and a method for manufacturing the same.

[Conventional technology]

2. Description of the Related Art Projection screens, such as transmissive screens and reflective screens, are widely used to project television images, microfilm images, and the like to achieve desired displays. This type of projection screen has one entrance plane and/or
Alternatively, a predetermined lens shape is attached to the exit surface, and a double-sided lenticular lens is generally used.

In this oak projection screen, misalignment of the lenses on both sides has a negative effect on the screen characteristics, so in order to obtain good characteristics, it is necessary to accurately align the lenticular lenses on both sides.

Incidentally, methods for manufacturing double-sided lenticular lenses currently in practical use include extrusion molding, cell casting, hot pressing, and the like. However, all of these methods involve directly or indirectly transferring a metal or other matrix to a resin plate, and the dimensional accuracy of the matrix, the mold temperature control accuracy during molding, and the alignment accuracy of the double-sided matrix Since it is difficult to perform all of the above to a sufficient degree, it has been difficult to sufficiently improve the positioning accuracy of a double-sided lenticular lens.

In recent years, there has been an increasing demand for high-definition large-sized televisions, and the lenticular lenses of projection screens are also required to have a finer pitch. It is not easy to reduce positional deviation and increase precision, and it has not been possible to sufficiently meet the demand for fine pinching.

Therefore, a method has been proposed to obtain a double-sided lenticular lens with no positional displacement, in which lens retraction is integrated on the incident surface side and the exit surface side by arranging transparent cylindrical bodies in parallel.

However, in these conventionally proposed methods, a barrier may occur between adjacent cylindrical bodies, and light rays leaking from the barrier may cause major defects on the screen (see-through hot band, etc.), which is not practical.

As a solution to this problem, the applicant has already developed a technique for obtaining a projection screen by melt-spinning a large number of plastic yarn strands, aligning the strands into a sheet, and fusing adjacent strands together. A patent has been applied for. It has also been proposed that a conjugate system be employed in this spinning, and the strand be composed of a transparent main part and a part having different optical properties from the main part.

[Problem to be solved by the invention]

The present invention overcomes the problems and technical background of the prior art described above, and solves the problem that when translucent strands are arranged in a sheet shape, there is no gap between adjacent lens units, and furthermore, the axial direction of the translucent strands is perpendicular to the axial direction of the translucent strands. The aim is to improve the directivity characteristics while avoiding loss of light quantity.

A further object of the present invention is to provide a method suitable for efficiently manufacturing such a projection screen.

[Means to solve the problem]

That is, the present invention has been made to achieve the above-mentioned problems, and its gist is to use a sheet-like structure in which a large number of transparent plastic strands are arranged in parallel, and The strands constituting these are fused together at the outer surfaces of the adjacent individual strands and integrated into a sheet, and a screen body is formed by one or more of these sheets. The first invention is a projection screen characterized in that at least four surfaces of the screen body are formed with finely uneven surfaces, and a large number of transparent plastic strands are arranged in a sheet shape. The above-mentioned strands constituting these are fused together at the outer surfaces of adjacent individual strands to form a sheet, and a screen body is formed by one or more of these sheets, and then The light-transmitting strands with fine irregularities are arranged in parallel on at least one surface to form a sheet-like material, so that the light-transmitting strands with fine irregularities are arranged in parallel on at least one surface and are pressed onto a mold surface having a fine irregularity pattern at a high temperature higher than the heat deformation temperature of the transparent strands. A method in which the above-mentioned strands constituting these are fused together at the outer surfaces of adjacent individual strands to form a sheet, and a screen body is formed from one or more of these sheets. A third method for producing a projection screen, which comprises mixing particles of a different type having a melting and cooling behavior different from that of the main body into the molding material for the translucent strand in advance, and then melt-spinning the translucent strand. The purpose is to make it an invention.

In the figure, (1Q) is a plastic translucent strand. Of these, Fig. 1 is an example in which the translucent strand (10) has a circular cross-sectional shape, Fig. 2 is an example in which the cross-sectional shape is oval, and Fig. 3 is an example in which the cross-sectional shape is approximately oval. This is an example of a case. Further, Figure @4 is an example in which the optical axis of the translucent strand (10) in the state shown in Figure 3 is gradually tilted to give it directivity toward the center. The outer surfaces of these adjacent translucent strands (10) are fused (11) and integrated as shown in FIG. 5, resulting in a sheet-like structure that constitutes a projection screen. has been done. Further, the projection screen of the present invention has an uneven surface (1
2) is formed, the transmitted light can be diffused from the operation button of this uneven surface (12) in a direction perpendicular to the axial direction of the translucent strand (10), generally in a vertical direction. It has characteristics that can improve properties.

The projection screen of the present invention is preferably composed of a single sheet integrated as described above, but is not necessarily limited to a single sheet, and may be composed of two or several sheets connected together. may be configured. Even when a plurality of sheets are connected in this way, the pitch accuracy is significantly improved compared to when simply arranging each strand one by one.

The light-transmitting strand (10) of the present invention is made of a plastic with good light transmission, such as a thermoplastic polymer such as an acrylic polymer, a polycarbonate polymer, or a polyacrylate polymer, a cross-linked silicone polymer, a cross-linked acrylate polymer, a 1-on bridge type polymer, etc. Manufactured from cross-linked hardening polymers, etc. At this time, the translucent strand (1o
) varies depending on the size, use, and purpose of the screen, but it is generally selected to be about Q1 to 15, which will sufficiently contribute to making the screen finer pitch. Further, the translucent strand (10) may be colored with a suitable coloring agent, or may be mixed with a light diffusing agent.

Such a projection screen can be manufactured by a melt spinning method, and the method will be explained below with reference to FIG. 6. That is, in the figure, (1) is an extruder, and (2) is a die equipped with a nozzle, which discharges molten plastic from an orifice. The arrangement i of the orifices may be selected to be convenient for taking up a large number of strands. At this time, a metering pump may be installed to ensure stability of the discharge amount.

The discharged strands are pressed together and fused together by a bent bar-shaped fusion guide (3) provided directly below the nozzle, and then arranged in a straight line by a bar-shaped alignment guide (4). Then, this is taken up by a taking-up guide (5) and irrigated onto a reel (6).

When manufacturing a projection screen by the method described above, as shown in FIG. 4, -
It is preferable to use a welding guide whose optical axis is deformed in this way to fuse the strands which have been discharged into an approximately oval shape, and by using this method, it is possible to perform the welding process in approximately the same manner as shown in FIG. 6.

In the illustrated example, the translucent strand Cl0) is first melt-spun and then taken up and integrated into a sheet immediately below the spinning. It is also possible to use a die that allows the sheets to be connected and to be integrated into a sheet.

In addition, the present invention is applicable not only to the production of translucent strands using a single polymer, but also to the production of strands with a core-sheath double structure using different polymers, such as optical fibers, or between the translucent strands. An external light absorbing layer may also be formed. When manufacturing the projection screen of the present invention, it is desirable to use a single sheet over the entire width of the screen, but if there are restrictions due to the equipment, a unit sheet of a predetermined width may be manufactured and then glued together. They may be connected using adhesive or adhesive tape.

Next, the formation of the uneven surface in the present invention will be explained.

FIG. 7 shows an example in which an approximately fly's eye-shaped uneven surface is formed on the observation side surface of the projection screen 1 of the present invention in a direction perpendicular to the axial direction of the translucent strand. ) is a translucent strand, (12) is an uneven surface, and (13) is an external light absorption layer formed between the translucent strands (10).

Such a projection screen can be formed by heat-pressing a sheet that has already been formed using a mold that has a surface opposite to the uneven surface. It is a diagram. Although this figure shows an example of one translucent strand (10), the translucent strand is attached to a mold (7) made of brass or the like with many arcuate grooves (71). (10
), then lay one mirror plate made of stainless steel etc. in order,
This can be placed between the upper and lower hot plates of a heat press machine and hot pressed according to a conventional method.

In addition, the size of the uneven surface at this time, the translucent strand C
If the diameter of l0) is 1125 m, the pinch between the groove of the mold and 71) should be 60 μ, and the depth should be about 2 Q μ. In addition, when manufacturing using acrylic resin, the temperature of the heating plate is 18
The temperature may be about 0°C.

When forming an uneven surface by hot pressing as described above, it is also possible to make it continuous, and FIG. 9 shows an example of this. That is, the transparent strand (1Q) in the form of a sheet is supplied to a heated molding roll (20), pressed and shaped with two rubber rolls (21), (21), and then passed through a quench roll (22). ) through the cooling tank (2
2).

The continuous method described above can also be carried out by melt-spinning translucent strands and incorporating the resulting sheet in a position where it is not cooled.

The formation of an uneven surface in the present invention is not limited to the above two examples, and can also be performed when manufacturing a translucent strand. In this method, when melt-spinning a translucent strand, different types of materials with different melting and cooling behavior, for example, one that protrudes from the surface when cooled and one that is recessed at I/-1, are mixed into the resin. This may be melt-spun using a method similar to that shown in FIG. As an example of this material to be mixed, when the base is an acrylic resin, styrene heat having an average particle size of 10 μm may be used, and thereby a finely uneven surface with a satin finish can be obtained.

(Effects of the Invention) Since the present invention is composed of the four-hole configuration described in detail above, it has high precision, can achieve sufficiently fine pitch, and has a well-balanced viewing angle in the horizontal and vertical directions. This method has the advantage that a projection screen with excellent performance can be obtained, and such a projection screen with excellent performance can be manufactured efficiently.

[Brief explanation of the drawing]

1 to 5 are cross-sectional views showing a part of the projection screen of the present invention, FIG. 6 is a schematic side view of an apparatus for manufacturing the present invention, and FIG. 7 is another embodiment of the present invention. FIGS. 8 and 9 are schematic perspective views showing a method for forming an uneven surface according to the present invention. (10)...Translucent strand (12)...Irregular surface γ Fig. n

Claims (1)

[Claims] 1. A sheet-like structure in which a large number of transparent plastic strands are arranged in parallel is used, and the strands constituting these strands are arranged on the outer surface of each adjacent strand. They are fused and integrated into a sheet, and a screen body is formed by one or more of these sheets, and a finely uneven surface is formed on at least one surface of the screen body. A projection screen characterized by: 2. The projection screen according to claim 1, wherein the finely uneven surface has a substantially fly's eye shape. 3. The projection screen according to claim 1, wherein the finely uneven surface is composed of streak-like unevenness orthogonal to the axial direction of the translucent strand. 4. It uses a sheet-like structure in which a large number of transparent plastic strands are arranged in parallel, and the above-mentioned strands constituting these strands are fused together on the outer surfaces of adjacent individual strands to form a sheet-like structure. and form a screen body by one or more of these sheets,
Next, the light-transmitting strand is pressed onto a mold surface having a finely uneven pattern at a high temperature higher than the heat deformation temperature, thereby forming a finely uneven surface on at least one surface of the projection screen. Production method. 5. It uses a sheet-like structure in which a large number of transparent plastic strands are arranged in parallel, and the above-mentioned strands constituting these strands are fused together on the outer surfaces of adjacent individual strands to form a sheet-like structure. This is a method of forming a screen body by a single sheet or a plurality of sheets, in which dissimilar particles having different melting and cooling behavior from the main body are mixed in advance into the molding material of the translucent strand, and then the transparent strand is A method for producing a projection screen, which comprises melt-spinning optical strands.