Diffusion sheet, backlight, liquid crystal display apparatus, and method of producing a diffusion sheet

Patent metadata

Field	Value
Publication number	US-9429690-B2
Application number	US-201213552816-A
Country	US
Kind code	B2
Filing date	Jul 19, 2012
Priority date	Aug 8, 2011
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

A diffusion sheet includes a light-transmissive substrate, a plurality of structures, and a flat portion. The light-transmissive substrate includes a first main surface, and a second main surface. The plurality of structures have convex shapes and are randomly formed on the first main surface. The flat portion is formed among the plurality of structures on the first main surface and has a surface roughness (Ra) of no less than 0.9 μm.

First claim

What is claimed is:

1. A diffusion sheet, comprising:
a light-transmissive substrate including:
a first main surface;
a second main surface;
a plurality of convex-shaped structures randomly formed on the first main surface; and
a portion where prisms are formed among the plurality of convex-shaped structures on the first main surface,
wherein the portion has a surface roughness (Ra) of no less than 0.9 μm and wherein a side-surface angle of each of the plurality of convex-shaped structures with the first main surface is no less than 65 degrees and no more than 90 degrees.

2. The diffusion sheet according to claim 1 , wherein the second main surface has a surface roughness (Ra) of no more than 0.5 μm.

3. The diffusion sheet according to claim 1 , wherein each of the plurality of convex-shaped structures has a partially spherical shape.

4. The diffusion sheet according to claim 1 , wherein the plurality of convex-shaped structures have a filling rate of no less than 60% and no more than 80% in the first main surface.

5. A backlight, comprising:
a diffusion sheet including:
a light-transmissive substrate including:
a first main surface;
a second main surface;
a plurality of convex-shaped structures randomly formed on the first main surface;
a portion where prisms are formed among the plurality of convex-shaped structures on the first main surface, wherein the portion has a surface roughness (Ra) of no less than 0.9 μm, and wherein a side-surface angle of each of the plurality of convex-shaped structures with the first main surface is no less than 65 degrees and no more than 90 degrees; and
a light source provided on a side of the second main surface.

6. A liquid crystal display apparatus, comprising:
a diffusion sheet including:
a light-transmissive substrate including:
a first main surface,
a second main surface,
a plurality of convex-shaped structures randomly formed on the first main surface;
a portion where prisms are formed among the plurality of convex-shaped structures on the first main surface, where the portion has a surface roughness (Ra) of no less than 0.9 μm, and wherein a side-surface angle of each of the plurality of convex-shaped structures with the first main surface is no less than 65 degrees and no more than 90 degrees;
a light source provided on a side of the second main surface; and
a liquid crystal panel provided on a side of the first main surface.

Assignees

• Sasaki Jun
• Horii Akihiro
• Sony Corp

Inventors

• Sasaki Jun
• Horii Akihiro

Classifications

• G02B5/0268

  characterized by the fabrication or manufacturing method · CPC title

• G02B5/02 Primary

  Diffusing elements; Afocal elements · CPC title

• G02B5/0231

  the surface having microprismatic or micropyramidal shape (macroscopic prism arrays G02B5/045) · CPC title

• G02B5/0221 Primary

  the surface having an irregular structure (G02B5/0226 takes precedence) · CPC title

• G02F1/1335

  Structural association of cells with optical devices, e.g. polarisers or reflectors · CPC title