Lens sheet for screen

• US 20060187545A1
• Filed: 07/29/2004
• Published: 08/24/2006
• Est. Priority Date: 07/31/2003
• Status: Active Grant

• Current Assignee: Dai Nippon Printing Company Limited
• Original Assignee: Dai Nippon Printing Company Limited
• Inventors: Doi, Yasuhiro
• Granted Patent: US 7,532,395 B2
• Time in Patent Office: Days
• US Class Current: 359/455
• CPC Class Codes: G02B 3/0031 Replication or moulding, e.g. hot embossing, UV-casting, injection moulding
• CPC Class Codes: G02B 3/0068 arranged in a single integral body or plate, e.g. laminates or hybrid structures with other optical elements G02B5/1885, G02B17/002, G02B30/27 take precedence
• CPC Class Codes: G02B 3/08 with discontinuous faces, e.g. Fresnel lens diffractive Fresnel lenses G02B5/1876
• CPC Class Codes: G03B 21/625 Lenticular translucent screens
• CPC Class Codes: Y10T 428/31909 Next to second addition polymer from unsaturated monomers

Abstract

There are provided a lens sheet for a screen, which is highly stable by virtue of a reduced tendency toward warping, lifting and the like of the lens caused by external humidity and, at the same time, has a suppressed tendency toward friction between lenses during transport as a screen, and a resin composition for constituting the lens sheet. The lens sheet is used in combination with other lens sheet and comprises one or at least two layers. When the layer in contact with the above other lens is formed of a thermoplastic resin, the universal hardness of the thermoplastic resin composition is brought to a range of 31.0 to 42.0 N/mm².

Claims

1. A lens sheet for a screen comprising one or at least two layers, adapted for use in combination with other lens sheet,

the layer in contact with said other lens being formed of a thermoplastic resin, said thermoplastic resin having a universal hardness of 31.0 to 42.0 N/mm².

2. The lens sheet for screen according to claim 1, wherein said thermoplastic resin has a compression modulus of elasticity of 1600 to 2500 MPa and a maximum deformation quantity of 2.0 to 2.7 μ

m as measured by a creep test.

3. The lens sheet for a screen according to claim 1, wherein said thermoplastic resin has a loss tangent at −

20°

C. of not less than 0.04 and an elastic work ratio of not less than 70%.

4. The lens sheet for a screen according to claim 1, wherein, when the lens sheet for a screen has a single-layer structure, said thermoplastic resin has a water absorption of not more than 0.2%.

5. The lens sheet for a screen according to claim 1, wherein, when the lens sheet for a screen comprises two or more layers, a relationship represented by α

1−

α

2>

0.1% is satisfied wherein α

1 represents the water absorption of the thermoplastic resin constituting the layer in contact with said other lens, %; and

α

2 represents the water absorption of the resin constituting the layer(s) other than the layer in contact with said other lens, %.

6. The lens sheet for a screen according to claim 1, wherein said thermoplastic resin composition comprises a copolymer of methyl methacrylate, styrene and butadiene rubber, and the content of said methyl methacrylate and styrene is not less than 20% by weight based on said copolymer.

7. Use of a lens sheet for a screen according to claim 1 as a lenticular lens.

8. A projection screen comprising a lenticular lens according to claim 7 and a Fresnel lens.

9. A thermoplastic resin for use in a lens sheet for a screen according to claim 1, said thermoplastic resin having a universal hardness of 31.0 to 43.0 N/mm².

10. A thermoplastic resin according to claim 9, which has a compression modulus of elasticity of 1600 to 2500 MPa and a maximum deformation quantity of 1.95 to 2.7 μ

m as measured by a creep test.

11. The thermoplastic resin according to claim 9, wherein said thermoplastic resin has a loss tangent at −

20°

C. of not less than 0.04 and an elastic work ratio of not less than 70%.