View angle-restriction sheet and flat panel display

Patent metadata

Field	Value
Publication number	US-9448341-B2
Application number	US-201314395277-A
Country	US
Kind code	B2
Filing date	Apr 22, 2013
Priority date	Apr 23, 2012
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

The view angle-restricting sheet includes an optically functional layer including: a plurality of first light transmission sections that are rectangular in cross section and arranged in a multi-stripe fashion; and one or more second light transmission section(s) that is/are each arranged between adjacent first light transmission sections. The first light transmission sections contain a light diffusing agent and a resin matrix. The proportion of the surface area occupied by the first light transmission sections with respect to the surface area of the optically functional layer is no less than 5% and no greater than 40%. The ratio (T 1 /W 1 ) of the thickness (T 1 ) to the width (W 1 ) of the first light transmission section is preferably no less than 4 and no greater than 40. The average distance between adjacent first light transmission sections is preferably no less than 6 μm and no greater than 400 μm.

First claim

The invention claimed is:

1. A view angle-restricting sheet comprising an optically functional layer which comprises:
a plurality of first light transmission sections that are rectangular in cross section and arranged in a multi-stripe fashion; and
one or more second light transmission section(s) that is/are each arranged between adjacent first light transmission sections,
wherein in the view angle restricting sheet,
the first light transmission sections comprises a light diffusing agent and a resin matrix,
a proportion of a surface area occupied by the first light transmission sections with respect to a surface area of the optically functional layer is no less than 5% and no greater than 40%,
a refractive index (n 1 ) of the matrix is greater than a refractive index (n 2 ) of the second light transmission section and a difference (n 1 −n 2 ) between the refractive index (n 1 ) of the matrix and the refractive index (n 2 ) of the second light transmission section is no less than 0.15,
the refractive index (n 1 ) of the matrix is greater than a refractive index (n 3 ) of the light diffusing agent, and a difference (n 1 −n 3 ) between a refractive index (n 1 ) of the matrix and a refractive index (n 3 ) of the light diffusing agent is no less than 0.03,
a ratio (T 1 /W 1 ) of a thickness (T 1 ) to a width (W 1 ) of the first light transmission section is no less than 7 and no greater than 40, and
an average distance between adjacent first light transmission sections arranged is no less than 50 μm and no greater than 400 μm,
a sharp image is displayed in a front direction using rays of light not entering the first light transmission section among rays of light having entered the second light transmission section, and leakage of information through glimmering from an oblique direction is prevented by allowing rays of light having entered the first light transmission section to exit after being diffused.

2. The view angle-restricting sheet according to claim 1 , wherein a mass ratio of the light diffusing agent to the matrix is no less than 0.1 and no greater than 2.

3. The view angle-restricting sheet according to claim 1 , wherein a refractive index (n 1 ) of the matrix is no less than 1.57.

4. The view angle-restricting sheet according to claim 1 , wherein the first light transmission section and the second light transmission section are arranged without any gap.

5. The view angle-restricting sheet according to claim 1 , wherein a front face of the optically functional layer is entirely flat.

6. The view angle-restricting sheet according to claim 1 , wherein a back face of the optically functional layer is entirely flat.

7. The view angle-restricting sheet according to claim 1 , comprising a protective layer provided on one face side of the optically functional layer.

8. The view angle-restricting sheet according to claim 7 , wherein a refractive index (n 4 ) of the protective layer is equal to a refractive index (n 2 ) of the second light transmission section.

9. The view angle-restricting sheet according to claim 1 , wherein the matrix comprises a pigment in a dispersion state.

10. The view angle-restricting sheet according to claim 1 , wherein the optically functional layer comprises one or more third light transmission section(s) that is/are provided crosswise with respect to the first light transmission sections and that comprise(s) a light diffusing agent and a resin matrix.

11. The view angle-restricting sheet according to claim 1 , which is provided on a front face side of a display panel of a flat panel display.

12. A flat panel display comprising the view angle-restricting sheet according to claim 11 .

Assignees

• Keiwa Inc

Inventors

• Tsuji Takahiro

Classifications

• G09F19/14

  displaying different signs depending upon the view-point of the observer · CPC title

• G02F1/133524

  Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides · CPC title

• G02F1/133504

  Diffusing, scattering, diffracting elements (associated to illuminating devices G02F1/133606) · CPC title

• G02B5/0205

  characterised by the diffusing properties · CPC title

• G02F1/1335

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