Optical film

• US 20010012158A1
• Filed: 02/01/2001
• Published: 08/09/2001
• Est. Priority Date: 02/02/2000
• Status: Active Grant

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Umemoto, Seiji, Ariyoshi, Toshihiko
• Granted Patent: US 6,636,358 B2
• Time in Patent Office: Days
• US Class Current: 359/599
• CPC Class Codes: G02B 1/10 Optical coatings produced by application to, or surface treatment of, optical elements G02B1/08 takes precedence
• CPC Class Codes: G02B 1/11 Anti-reflection coatings
• CPC Class Codes: G02B 1/18 Coatings for keeping optical surfaces clean, e.g. hydrophobic or photo-catalytic films G02B1/16 takes precedence
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133616 Front illuminating devices

Abstract

An optical film includes a transparent film having provided on one side thereof an adhesive layer, a layer which includes a plurality of groove structures, each structure having optical-path changing slopes oriented substantially toward certain directions at an angle of 35 to 48 degrees relative to the transparent film, and which is laid on the other side of the transparent film, a transparent cover film for covering the surface of the layer in which the groove structures are formed, and at least an anti-reflection layer and an anti-moisture layer laid on an exterior side of the cover film.

Claims

1. An optical film comprising:

a transparent film;

an adhesive layer provided on one side of said transparent film;

a layer including a plurality of groove structures, each structure having optical-path changing slopes oriented substantially toward certain directions at an angle of 35 to 48 degrees relative to the transparent film, and said layer being laid on the other side of said transparent film;

a transparent cover film for covering the surface of the layer in which the groove structures are formed; and

at least an anti-reflection layer and an anti-moisture layer laid on an exterior side of the-cover film.

2. An optical film according to

claim 1

, wherein the optical-path changing slopes oriented substantially toward certain directions are made up of two or more planes such that, if one of the planes is taken as a reference, the other plane is oriented in the opposite direction.

3. An optical film according to

claim 1

, wherein an antiglare layer is interposed between the cover film and the anti-reflection layer, and the adhesive layer is covered with a release liner.

4. An optical film according to

claim 1

, wherein the optical-path changing slopes are tilted at an angle of 38 through 45 degrees.

5. An optical film according to

claim 1

, wherein areas on one surface of the optical film occupied by flat planes which are inclined at an angle of less than five degrees relative to the surface of the optical film are five times or more areas occupied by slopes inclined at an angle of 35 degrees or more.

6. An optical film according to

claim 1

, wherein the cross sections of the groove structures assume substantially the shape of an -isosceles triangle, the shape of another type of triangle, or the shape of a rectangle.

7. An optical film according to

claim 1

, wherein the groove structures are made of consecutive grooves extending from one end of the optical film to the other end, or discontinuous grooves whose lengths are five times or more the depths thereof and which have optical-path changing slopes in the lengthwise direction of the groove structures.

8. An optical film according to

claim 1

, wherein ridge lines of the optical-path changing slopes are parallel with one side of the transparent film or tilted at an angle of ±

30°

or less relative to the same.

9. An optical film according to

claim 1

, wherein the adhesive layer is of optical diffusion type.