JP2931017B2 - Method of manufacturing projection screen - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a projection screen used as a screen of a projection television, a microfilm reader, or the like.

[Problems to be Solved by Conventional Techniques and Inventions] Projection screens, such as transmission screens and reflection screens, are widely used to project television images, microfilm images, and the like, and to realize intended displays. ing. This type of projection screen is provided with a predetermined lens shape on an entrance surface and / or an exit surface so that the observer is bright when the observer observes the image and the viewing angle is enlarged.
Generally, a double-sided lenticular lens is used.

In such a projection screen, the axial deviation of the lenses on both sides adversely affects the screen characteristics. Therefore, in order to obtain good characteristics, it is necessary to accurately align the lenticular lenses on both sides.

By the way, as a method of manufacturing a double-sided lenticular lens which is currently in practical use, there are an extrusion molding method, a casting method by cell casting, a hot pressing method, and the like. All of these methods directly or indirectly transfer a metal mold or the like to a resin plate. The dimensional accuracy of the mold, the temperature control of the mold during molding, and the positioning accuracy of the double-sided mold. Since it is difficult to perform all of the above operations sufficiently, it has been difficult to sufficiently improve the positioning accuracy of the double-sided lenticular lens.

In recent years, there has been an increasing demand for high-definition large-screen televisions, and lenticular lenses for projection screens have also been required to have fine pitches. However, it was not easy to achieve high precision by minimizing the positional deviation, and it was not possible to sufficiently meet the demand for fine pitch.

In view of this, a method has been proposed in which transparent columnar bodies are arranged in parallel to obtain a double-sided lenticular lens in which a lens unit is integrated on the incident surface side and the output surface side without displacement.

However, in these methods which have been conventionally proposed, a gap is generated between adjacent columnar bodies, and light rays leaking therefrom may cause a large defect (see-through, hot band, etc.) on the screen, which is not practically preferable.

As a solution to this problem, the present applicant has already applied for a patent application to obtain a projection screen by melt-spinning a large number of plastic strands, aligning the strands in a sheet shape, and welding adjacent strands together. doing. It has also been proposed to adopt a conjugate method in this spinning and to configure the strand with a transparent main part and a part having optical characteristics different from the main part.

The present invention has been made in view of the above-described problems and technical background of the related art, and provides a projection screen having excellent optical matching accuracy of lens units on both sides, no gap between adjacent lens units, and further excellent characteristics. The purpose is to do so.

Another object of the present invention is to provide a method suitable for producing such a projection screen.

[Means for Solving the Problems] According to the present invention, the above object is achieved by arranging a large number of plastic-based strands in parallel. A light absorbing portion provided along the longitudinal direction in contact with both side portions on the observation side of the main body portion, and adjacent strands are joined via the light absorbing portion and integrated into a sheet shape. In a method of manufacturing a projection screen,
A large number of spins of the melt of the plastic material serving as the main portion and the plastic material and the melt serving as the light absorbing portion are performed in a conjugate manner, and these plastic strands are melted through the light absorbing portion. In the method for manufacturing a projection screen, the method for manufacturing a projection screen according to the present invention is characterized in that the screen is formed using at least one of the sheets, and is different from the main part. There is a mode in which a melt of a plastic material serving as an auxiliary part of the optical properties is simultaneously conjugate-spun to provide an auxiliary part along the sheet surface and forming a part of the strand.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a view showing a transmission screen as an example of a projection lens according to the present invention, and FIG. 2 is a partially enlarged view of FIG.

In these figures, reference numeral 10 denotes a plastic strand, which extends in the direction perpendicular to the paper surface with the same cross-sectional shape. The strand comprises a main part 11 made of a transparent plastic material, an auxiliary part 12 made of a plastic material mixed with a light diffusing agent, and a light absorbing part 13 made of a plastic material mixed with a light absorbing part.

The main body 11 has upper and lower convex curved surfaces for transmitting light, and the left and right sides are substantially tapered. The auxiliary part 12 is formed as a relatively thin layer on the upper curved surface of the main part 11. The light absorbing portions 13 are formed in a wedge shape at portions where light is generally not transmitted on both side portions of the upper half portion of the main body portion 11, and the light absorbing portions of adjacent strands 10 are joined by fusion. . Reference numeral 14 denotes a fusion bonding portion.

Examples of the material of the main body 11 include plastics having good light transmission properties, such as thermoplastic polymers such as acrylic polymers, polycarbonates, and polyarylates, and cross-linked silicone polymers, cross-linked arylate polymers, and cross-linked polymers such as ion-cross-linked polymers. Curable polymers are used.

As the material of the auxiliary portion 12, a material obtained by mixing a light diffusing agent such as silica particles in the same material as the main portion 11 is used.

As the light absorbing portion 13, a material obtained by mixing a light absorbing agent made of a black pigment such as carbon black into the same material as the main body portion 11 is used.

In this example, light is incident on the lower surface. Then, the incident light is appropriately condensed by the lower surface of the main body 11, and eventually the auxiliary
, Where it is appropriately diffused and exits upward.
That is, the upper side is the observation side.

According to this example, it is possible to increase the resolution of the screen as compared with the case where the light diffusing agent is mixed in the entire main body 11. Further, unnecessary external light is absorbed by the light absorbing portion 13 provided on the observation side, so that the contrast of the screen can be improved.

In this example, the adjacent strand 10 is a light absorbing portion.
The sheet 13 is fused and integrated through the sheet 13. For this reason, the non-circular cross-sectional shape of the strand 10 is not easily collapsed, and the bonding strength is increased because the fusion area is sufficiently large.

The projection screen according to the present invention is preferably a single integrated sheet described above, but is not necessarily limited thereto, and is configured by combining a plurality of the above sheets, for example, by bonding with an adhesive or an adhesive tape. You can also.

The width of one strand of the strand 10, that is, the lenticular pitch, varies depending on the size, application, and purpose of the screen, but can be, for example, 0.1 to 1.5 mm, which can sufficiently contribute to fine pitch.

In the above example, the light diffusing layer is used as the auxiliary portion 12. However, the auxiliary portion may be a portion made of a material having a different refractive index from the main portion, for example, and the refractive index difference may be appropriately selected to obtain a screen view. The range can be adjusted.

In addition to the colorless and transparent one, the transparent main part 11 may be a colored and transparent part mixed with an appropriate coloring agent, or a part entirely mixed with a light diffusing agent. still,
When mixing the light diffusing agent into the main body 11, the auxiliary
May be omitted or the characteristics may be different from those of the main body 11.

The screen as described above can be manufactured by using a conjugate melt spinning method.

3 to 6 are explanatory views of the manufacturing method, FIG. 3 is a schematic plan view of the apparatus, FIG. 4 is a schematic front view of the apparatus, FIG. 5 is a schematic side view of the apparatus, FIG. 6 is a schematic bottom view of the nozzle portion of the apparatus.

In these figures, reference numeral 1 denotes a first extruder for melt-extruding a material for forming the main portion 11, and reference numeral 2 denotes a second extruder for melt-extruding a material for forming the auxiliary portion 12. Reference numeral 3 denotes a third extruder for melt-extruding a material for forming the light absorbing portion 13. Reference numeral 4 denotes a die, which has a nozzle 4A. The nozzle discharges three types of molten plastic from the orifice 4B. The opening shape of each orifice 4B is substantially the shape of the strand 10 shown in FIG. Reference numeral 5 denotes a fixed-rate supply pump, which is used to control the amount of the melt supplied separately to the die 4.

Strands 10 spun and discharged by a conjugate method using the above three types of melts are attitude-controlled by a grooved alignment guide 6 provided immediately below the nozzle,
Further, by passing through the fusion guide 7 whose center is concave, only the light absorbing portions 13 of the adjacent strands 10 are fused together. Thereby, the spinning strands 10 can be integrated into a sheet to form a transmission screen.

Reference numeral 8 denotes a nip roller for picking up and 9
Is a cutter for cutting the sheet into appropriate lengths.

 Hereinafter, examples of the screen production of the present invention will be described.

[Embodiment] The above-mentioned FIGS.
The transmission screen shown in the figure was manufactured.

Polymethyl methacrylate having a refractive index n = 1.49 (hereinafter abbreviated as “PMMA”) is used as a material of the main body portion 11, and the PMMA mixed with silica particles as a light diffusing agent is used as the auxiliary portion 12; The above-mentioned PMMA
Used was mixed with carbon black as a light absorber.

Then, using a nozzle 4A having orifices 4B with 500 holes arranged as shown in FIG. 6, the main part material is 0.6 g / hole / minute, the auxiliary part material is 0.2 g / hole / minute, and the light absorbing part material is 0.2 g / hole / minute. g / hole / minute, and the spinning temperature is 240 ° C.
The conjugate is spun and 500 strands 10 are simultaneously discharged, and after the spinning, the alignment guide 6 and the fusion guide 7
Through a nip roller 8 as a sheet.
It was picked up at a speed of 74m / min.

At this time, the distance from the nozzle 4A to the alignment guide 6 was set to 150 mm, and the alignment guide was forcibly cooled so that the surface temperature became constant.

The sheet obtained as described above had an arrangement pitch of the strands of 0.4 mm, was linearly and uniformly arranged and integrated, and had a width of 20 cm. 1m length of this sheet is 5
The sheets were arranged side by side and bonded with an adhesive tape to obtain a 1m × 1m transmission screen.

When this transmissive screen was attached to a projection television, an image with a wide viewing angle and good resolution and contrast was obtained.

In the above embodiments, the transmission screen is exemplified. However, the screen manufactured according to the present invention can be used as a reflection screen by providing a reflection layer on one surface.

[Effects of the Invention] As described above, in the projection screen of the present invention, a large number of plastic strands having light absorbing portions in contact with both sides of the main body portion are arranged in the form of a sheet, and adjacent strands are arranged via the light absorbing portions. Since it is bonded, the optical matching accuracy of the lens units on both sides is good, there is no gap between adjacent lens units, and the bonding strength is large. In particular, the above light absorbing parts are provided on both sides of the main part on the observation side Therefore, optical characteristics including contrast are remarkably excellent.

Further, according to the method of the present invention, such a screen as described above can be efficiently manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing a transmission screen as an example of a projection lens according to the present invention, and FIG. 2 is a partially enlarged view of FIG. 3 to 6 are explanatory views of a method for manufacturing a projection lens according to the present invention, FIG. 3 is a schematic plan view of the apparatus, FIG. 4 is a schematic front view of the apparatus, and FIG. FIG. 6 is a schematic view of a bottom surface of a nozzle portion of the apparatus. 1,2,3: Extruder, 4: Die, 4A: Nozzle, 4B: Orifice, 5: Metering pump, 6: Alignment guide, 7: Fusing guide, 8: Nip roller, 9: Cutter, 10 : Plastic strand, 11: main part, 12: auxiliary part, 13: light absorbing part, 14: fusion part.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03B 21/56-21/64

Claims (2)

(57) [Claims] A plurality of plastic strands are arranged in parallel, and each of said strands is in contact with a light-transmitting main portion and both side portions of the main portion on the observation side along a longitudinal direction. A light absorbing portion provided, and a method for manufacturing a projection screen in which adjacent strands are joined via the light absorbing portion and integrated into a sheet shape, wherein the plastic material to be the main portion is A large number of the melt and the melt of the plastic material to be the light absorbing portion are spun in a conjugate system, and these plastic strands are fused through the light absorbing portion to be integrated into a sheet. A method for manufacturing a projection screen, comprising forming a screen using at least one of the sheets. 2. An auxiliary part forming a part of the strand along the sheet surface by simultaneously conjugate-spinning a melt of a plastic material serving as an auxiliary part having optical characteristics different from that of the main part. Claim 1 characterized by the following:
13. The method for producing a projection screen according to the above.