JPH0222637A - Novel screen - Google Patents

Abstract

PURPOSE:To obtain the thin screen for which a methacrylic resin is used by using a biaxially stretched methacrylic resin sheet as a core material and providing lens-shaped ruggedness of a resin cured by UV on the surface thereof. CONSTITUTION:The biaxially stretched methacrylic resin sheet is used as the core material and the lens-shaped ruggedness consisting of the resin cured by UV rays is provided on the surface thereof. The thin screen having the high- accuracy lenses of a small pitch is obtd. in this way. The screen has the advantages including the high toughness and optical properties of the biaxially stretched methacrylic resin sheet and the fine shape reproducibility of the UV curing resin and is most suitable for the screen for high-vision broadcasting.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel transmissive or reflective screen for use in televisions, video projectors, etc.

[Conventional technology]

Various types of screens are currently used for general transmissive video projectors and the like, and the transmissive screen is constructed as shown in FIG. 3, for example. In Fig. 3, 1 is a light source, 2 is a 7-lens lens for parallelizing the light rays from the light source 1, 3 is its lens surface, 4 is a lenticular lens for adjusting the viewing angle, 6 is the same lens surface, Reference numeral 8 indicates the back surface of 7, and 5 indicates a light-diffusing material constituting the lenticular lens 4. A light shielding portion 9 is provided at a position on the back surface of the lenticule 2 corresponding to the non-light transmitting portion 7 of the concave portion of the lens surface. Screens used as screens include those with a lenticular lens also provided on the back surface 8, and the lenticular lens 11 shown in FIG.
A single-piece screen that combines a 7-lens lens and a 7-lens lens lO is also used.

〔Problems to be solved〕

Recently, there has been a demand for screens that can display precise images. That is, as the definition of television, video, etc. displays becomes higher and the dot pitch becomes smaller, there is a need for screens that can display images with precision suitable for this. In the future, high-definition television broadcasting using communication satellites is planned, and a screen capable of displaying precise images suitable for this is required.

To improve the precise image display of a transmissive or reflective screen, it is effective to reduce the pitch of the lenticular lens or Fresnel lens. To reduce the pitch, it is necessary to reduce the thickness of the screen. . On the other hand, lenticular lenses need to have high total light transmittance and good diffusion performance, and for this reason, methacrylic resin is the most suitable material for the screen.

Methacrylic resin has excellent optical properties, is hard and has high rigidity, but has the disadvantage of poor impact resistance and easy breakage when made into a thin wall. [Means for Solving the Problems] The present invention has solved the above problems. , a thin screen made of methacrylic resin. That is, the present invention has the following features: (1) A screen having a biaxially stretched methacrylic resin sheet as a core material and having lens-like irregularities made of an ultraviolet-cured resin on its surface; and the screen described in [1] above which is a Fresnel lens (3) the average thickness of the screen is 0.1 = 1.0 a
(4) The screen according to item 1.2 or item 3, which is a screen for a television or video projector, is provided.

That is, in the present invention, toughness is imparted by t-biaxial stretching of a methacrylic resin, and ultraviolet rays (hereinafter abbreviated as UV) are applied.

) Provides a new screen with a fine lenticular lens or 7-lens lens formed on the surface using a hardening resin.The methacrylic resin mentioned above has methyl methacrylate (hereinafter abbreviated as MMA) as its main component. It is a polymer, such as an MMA polymer (hereinafter abbreviated as PMMA), a copolymer containing MMA, and a mixture of various compounds added thereto.

As the MMA copolymer, MMA and alkyl acrylate copolymer (hereinafter abbreviated as Co (MMA-AA)) can be favorably used. Alkyl acrylates include methyl acrylate, ethyl acrylate, propyl acrylate,
1 to 10% by weight copolymers such as ethyl acrylate and 2-ditylhexyl acrylate can be used favorably. M
MA-maleic anhydride-methylef ternary copolymer, MM
Heat-resistant acrylic resins such as A-methylmethacrylamide copolymer can also be used satisfactorily. In addition, one or more copolymers of MMA and styrene, styrene derivatives, acrylonitrile, methacrylate, acrylic acid, and methacrylic acid can be used. Various additives such as a diffusing agent can be added to the acrylic resin.

Biaxially stretched sheet of methacrylic resin is disclosed in Japanese Patent Application Laid-Open No. 1986-190.
It can be molded by the press stretch molding method shown in Japanese Patent No. 331 and the like. That is, in the method of forming an oriented molded product by compressing a synthetic resin base in a compression gouer, two or more layers of thermoplastic resin bases are placed one on top of the other in an L die in a non-adhered state, and two or more dies are formed. Bring the interface between the inner surface and the surface of the resin base into a lubricated state, 1) Compress at a temperature above the glass transition temperature and below the melting point of the resin base to orient the resin base, 1) Take out the inside of the cooling ridge die, and separate each base. This is a compression molding method for oriented molded products in which two or more molded products are obtained by mutually peeling oriented molded products.The stretching ratio of the biaxially stretched sheet must be at least twice the area ratio. It is preferably 3 times or more and 25 times or less. If the stretching ratio is less than 2 times, no stretching effect will be exhibited, and if the stretching ratio is 3 times or more, the impact strength etc. will be greatly improved.

The biaxially stretched sheet of the acrylic resin of the present invention has an average O of
It is preferable that R8 has a high degree of biaxial orientation of ls Kg/ai or more. More preferably 20 #40
It is OR8 of KF/-. OR8 measurement method is ASTM
Compliant with D 1504. OR8 is the stress generated when the oriented molecules of the film or sheet try to return to their original state by heating, and indicates the degree of orientation.

The biaxial orientation described here refers to uniform orientation in two axial directions, and includes slight differences in OR8 and stretching ratio in the two axial directions. A multiaxially oriented sheet that is uniformly oriented in each direction is optically uniform and can be favorably used in the present invention. Multiaxially oriented sheets are generally included in biaxially oriented sheets, and are also included in the biaxially stretched sheets of the present invention.

The UV-cured resin described in the present invention is a transparent resin that polymerizes by irradiating liquid monomers with UV 1a at room temperature, and has more than 1 UV-activated functional group per monomer. It is a resin polymerized from monomers such as acrylic monomers, and resins polymerized from acrylic monomers are most preferable. A diffusing agent and the like can be added to this resin.

As a UV curable polyfunctional acrylic monomer, 1.6-
Hexanediol diacrylate, diethylene glycol diacrylate, neointylene glycol diacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate, intererythritol triacrylate, and the like can be used. Other examples include polyurethane acrylate and epoxy acrylate.

In order to form lenses of UV-curable resin, a good method is to press a UV-curable monomer Ksx axis-stretched methacrylic resin sheet coated on the surface of a lens-shaped mold, and then polymerize it by irradiating UV from the methacrylic resin sheet side. Can be used when busy.

The lens described in the present invention is a lenticular lens, a Fresnel lens, or a modified version of these lenses. The lenses may be formed on one or both sides of the screen. The screen of the present invention may be used alone or as part of a combination of two or more screens.

The average thickness of the screen of the present invention is preferably o, i to 1.0°0. The function of the screen of the present invention is maximized when used in a thin screen of 1.0w1 or less. In other words, the brittleness of methacrylic resin when made into a thin layer can be strengthened by using a biaxially stretched sheet, and fine lenses with a small pitch can be formed using UV curing resin. Thickness is preferred.

FIGS. 1 and 2 show cross-sectional views of the screen of the present invention. In FIG. 1, the core material 12 is a biaxially stretched methacrylic resin sheet, and both surfaces 13 and 14 are lenticular lenses made of UV-cured resin.

FIG. 2 shows a case where one surface is a lenticular lens 15 and the other surface is a Fresnel lens 16.

[Example] (Formation of biaxially stretched PMMA sheet) Weight average molecular weight of 1:2 million polymerized by cell cast method
Thick and smooth PMMA sheet (glass transition temperature 10
5°C) as a resin base, stack 20 sheets of the base, and place a 100μ polypropylene release sheet on the interface of each base.
A mirror-finished sheet with a thickness of m was placed, and the 20-layered thick-walled base material was vacuum-packed with the polypropylene sheet described above to obtain a base material for compression biaxial orientation molding. Polydimethylsiloxane was applied to the inner surface of the compressed goo, and the compressed goo and the resin base were heated to 150° C. and compressed to form a plug 70, which was biaxially oriented with an area ratio of 4 times. After cooling the compression goo and cooling the biaxially oriented molded product, take out the molded product from the compression goo, peel each molded product from each other, and then peel off the polypropylene to form a smooth surface.
．． 25m thick surface area ratio 4 times stretched PMMA2 with smooth surface
Twenty axially oriented sheets were obtained.

O of molded 0,25 w thick PMMA biaxially oriented sheet
R8 was 24 Kg/aIi.

(Formation of lenses using UV-cured resin) Using a lenticular lens mold made of brass,
．． A UV-curable resin lens was formed on the surface of a 25 m thick biaxially stretched PMMA sheet by the following method.

First, a primer (ACTsoo) manufactured by Seiko Advance ■ was applied thinly to the surface of the biaxially stretched PMMA sheet.

Next, on the surface of the lens mold, UV rays manufactured by Seiko r Avance ■ were applied.
A cured resin monomer (UV8481) is applied, and a biaxially stretched PMMA sheet is pressed onto it so that the Thalaimer coated surface contacts the monomer and air is not trapped, and UV irradiation is applied sufficiently from the PMMA sheet side. Then, the melon was cured. The biaxially stretched PMMA sheet was peeled from the mold to obtain a biaxially stretched PMMA sheet with lenses formed on one side.

2@The opposite side of the stretched PMMA coat was similarly subjected to primer treatment and lens formation using UV curing resin to obtain the screen of the present invention shown in Figure M3.

〔Effect of the invention〕

According to the present invention, a thin screen having high-definition lenses with a small pitch can be favorably provided. That is, it takes advantage of the toughness and optical properties of biaxially oriented methacrylic resin and the fine mold reproducibility of UV-cured resin, and is most suitable for future high-definition broadcasting screens.

[Brief explanation of the drawing]

FIGS. 1 and 2 show cross sections of the screen of the present invention. FIG. 3 shows an example of a transmission type screen, which is a lens with a front and back side of the screen that includes an optical error lens and a 7-lens lens.

Claims (1)

[Claims] A screen with a biaxially stretched methacrylic resin sheet as the core material and lens-shaped unevenness made of ultraviolet-cured resin on the surface.