LIGHT DIFFUSION MEMBER, METHOD OF MANUFACTURING SAME, AND DISPLAY DEVICE

• US 20130329401A1
• Filed: 03/01/2012
• Published: 12/12/2013
• Est. Priority Date: 03/03/2011
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Yamamoto, Emi, Kanno, Toru, Maeda, Tsuyoshi
• Granted Patent: US 9,341,345 B2
• Time in Patent Office: Days
• US Class Current: 362/97.2
• CPC Class Codes: F21V 13/12 Combinations of only three kinds of elements
• CPC Class Codes: G02B 5/0247 by means of voids or pores
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133562 on the viewer side

Abstract

A light diffusion member includes a light-transmissive base, a plurality of light diffusion portions, a connecting portion, and a light absorbing layer. The light diffusion portions are arranged on one surface of the base and have light-incident end surfaces each positioned on the side away from the base and having a larger area than a light-emergent end surface thereof. The connecting portion connects at least two adjacent ones of the plural light diffusion portions to each other, and is positioned near the light-incident end surfaces of the adjacent light diffusion portions. The light absorbing layer is formed on the one surface of the base in a region different from a region where the light diffusion portions are formed. A size from the light-incident end surface to the light-emergent end surface of the light diffusion portion is larger than a thickness of the light absorbing layer.

Claims

1. A light diffusion member comprising:

a light-transmissive base;

a plurality of light diffusion portions arranged on one surface of the base, the light diffusion portions each having a light-emergent end surface positioned on a side close to the base, and a light-incident end surface positioned on a side away from the base and having a larger area than the light-emergent end surface;

at least one connecting portion connecting at least two adjacent ones of the plural light diffusion portions to each other, the connecting portion being positioned near the light-incident end surfaces of the adjacent light diffusion portions; and

a light absorbing layer formed on the one surface of the base in a region different from a region where the light diffusion portions are formed,

wherein a size from the light-incident end surface to the light-emergent end surface of the light diffusion portion is larger than a thickness of the light absorbing layer.

2. The light diffusion member according to claim 1, wherein a total area of the coupling portions is not less than 30% of a total area of the light-incident end surfaces of the light diffusion portions.

3. The light diffusion member according to claim 1, wherein the light diffusion portions are aperiodically arranged when looked from a direction normal to the one surface of the base.

4. The light diffusion member according to claim 1, wherein the light diffusion portions are arranged such that air exists in gaps between the light diffusion portions.

5. The light diffusion member according to claim 1, wherein the light diffusion portions are arranged such that gas exists in gaps between the light diffusion portions.

6. The light diffusion member according to claim 5, wherein the gas is inert gas.

7. The light diffusion member according to claim 5, wherein the gas is nitrogen or argon.

8. The light diffusion member according to claim 1, wherein a size of the light-emergent end surface of at least one of the plural light diffusion portions is different from a size of the light-emergent end surfaces of the other light diffusion portions.

9. The light diffusion member according to claim 1, wherein an inclination angle of a lateral surface of at least one of the plural light diffusion portions is different from an inclination angle of lateral surfaces of the other light diffusion portions.

10. The light diffusion member according to claim 1, wherein an inclination angle of a lateral surface of at least one of the plural light diffusion portions is different depending on positions.

11. The light diffusion member according to claim 1, wherein a shape of the light diffusion portion in a plan view is substantially circular or substantially polygonal when looked from a direction normal to the one surface of the base.

12. The light diffusion member according to claim 1, further comprising at least one of an antireflection layer, a polarizing filter layer, an antistatic layer, an anti-glaring processed layer, and an antifouling processed layer, which is disposed on an opposite surface of the base to the one surface thereof.

14. A display device comprising a display main unit, and a viewing-angle widening member disposed on a viewing side and causing incident light from the display main unit to emerge therefrom in a state having a wider angle distribution than the light before entering the viewing-angle widening member,

wherein the viewing-angle widening member includes the light diffusion member according to claim 1.

15. The display device according to claim 14, further comprising:

an adhesive layer between the light diffusion member and a viewing side of the display main unit,

wherein the coupling portion is contacted with the adhesive layer, and

the adhesive layer is arranged such that the adhesive layer and air exist in gaps between the light diffusion portions.

16. The display device according to claim 14, wherein the display main unit includes a plurality of pixels forming a displayed image, and

an average pitch between adjacent ones of the plural light diffusion portions of the light diffusion member is smaller than a pitch between the pixels of the display main unit.

17. The display device according to claim 14, further comprising an information input device disposed on a viewing side of the viewing-angle widening member.

18. The display device according to claim 14, wherein the display main unit includes a light source and a light modulation element for modulating light emitted from the light source, and

the light source emits directional light.

19. The display device according to claim 14, wherein the display main unit is a liquid crystal display element.

13. A method of manufacturing a light diffusion member, the method comprising the steps of:

forming a light absorbing layer, which has openings, on one surface of a light-transmissive base;

forming a negative photosensitive resin layer, which is light-transmissive, on the one surface of the base in covering relation to the light absorbing layer;

applying diffused light to the negative photosensitive resin layer through the openings in the light absorbing layer from an opposite surface of the base to the one surface thereof on which the light absorbing layer and the negative photosensitive resin layer are formed; and

developing the negative photosensitive resin layer after being irradiated with the diffused light, thereby forming, on the one surface of the base, a plurality of light diffusion portions each having a light-emergent end surface positioned on a side close to the base, and a light-incident end surface positioned on a side away from the base and having a larger area than the light-emergent end surface, the light diffusion portions being in a state that at least part of adjacent ones of the light diffusion portions are coupled to each other in at least part of regions thereof on a same side as the light-incident end surfaces.