STRIPED DIFFUSER, METHOD OF MANUFACTURING THE SAME, AND LIQUID CRYSTAL DISPLAY DEVICE WITH ADJUSTABLE VIEWING ANGLE EMPLOYING THE STRIPED DIFFUSER

• US 20090310064A1
• Filed: 02/12/2009
• Published: 12/17/2009
• Est. Priority Date: 06/16/2008
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Hwang, Seongmo, CHOE, Kyumin, Lee, Moongyu
• Granted Patent: US 8,913,216 B2
• Time in Patent Office: Days
• US Class Current: 349/64
• CPC Class Codes: G02B 2207/123 Optical louvre elements, e.g. for directional light blocking
• CPC Class Codes: G02B 5/0242 by means of dispersed particles
• CPC Class Codes: G02B 5/0263 with positional variation of the diffusing properties, e.g. gradient or patterned diffuser
• CPC Class Codes: G02B 5/0268 characterized by the fabrication or manufacturing method
• CPC Class Codes: G02B 5/0278 used in transmission
• 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
• CPC Class Codes: G02F 1/133567 on the back side

Abstract

Provided are diffuser, method of manufacturing same, and liquid crystal display device employing the diffuser. Liquid crystal display device includes: backlight unit; liquid crystal panel on which image is formed by using light emitted by backlight unit, and comprising: color filter comprising plurality of pixels each of which comprises plurality of subpixels that are alternately arranged and transmit light in different wavelength bands; and liquid crystal layer whose transmittance is adjusted under electrical control; and diffuser disposed on a top surface or a bottom surface of the liquid crystal panel and comprising diffusing areas and transparent areas which alternate with each other at intervals corresponding to the width of the subpixels, wherein the liquid crystal layer comprises liquid crystal areas corresponding to the diffusing areas and liquid crystal areas corresponding to the transparent areas and the transmittances of the liquid crystal areas are adjusted according to the subpixels.

Claims

1. A diffuser comprising diffusing areas and transparent areas which alternate with each other.

2. The diffuser of claim 1, wherein the diffusing areas and the transparent areas which alternate with each other form striped patterns.

3. The diffuser of claim 1, wherein a width of each of the diffusing areas is equal to or greater than a width of each of the transparent areas.

4. The diffuser of claim 3, wherein a ratio of the width of the each of the diffusing areas to a pitch of the diffusing areas ranges from 0.5 to 0.9.

5. The diffuser of claim 1, further comprising:

a substrate; and

diffusion parts formed of a transparent resin including a plurality of diffusing particles, disposed in the diffusing areas and arranged on the substrate to be spaced apart from one another,

wherein spaces between the diffusion parts are the transparent areas.

6. The diffuser of claim 5, wherein the substrate is formed of a transparent material.

7. The diffuser of claim 5, wherein the substrate is a polarizing plate.

8. A method of manufacturing a diffuser comprising diffusing areas and transparent areas which alternate with each other, the method comprising:

forming a transparent resin layer, which includes a plurality of diffusing particles and is curable by ultraviolet rays, on a substrate;

disposing a mask having stripe-shaped openings on formed transparent resin layer and the substrate and emitting ultraviolet rays to the transparent resin layer; and

removing portions of the transparent resin layer not exposed to the ultraviolet rays and not cured.

9. The method of claim 8, wherein a width of each of the stripe-shaped openings is determined so that a width of each of the diffusing areas formed based on the striped-shaped openings, is equal to or greater than a width of each of the transparent areas.

10. The method of claim 9, wherein the width of each of the stripe-shaped openings and a pitch of the stripe-shaped openings are determined so that a ratio of the width of the each of the diffusing areas to a pitch of the diffusing areas ranges from 0.5 to 0.9.

11. The method of claim 8, wherein the substrate is formed of a transparent material.

12. The method of claim 8, wherein the substrate is a polarizing plate.

13. A liquid crystal display device comprising:

a backlight unit;

a liquid crystal panel which forms an image using light emitted by the backlight unit, and comprising;

a color filter comprising a plurality of pixels each of which comprises a plurality of subpixels that transmit light in different wavelength bands; and

a liquid crystal layer whose transmittance is adjusted under an electrical control; and

a diffuser disposed on a top surface of the liquid crystal panel or a bottom surface of the liquid crystal panel, the diffuser comprising diffusing areas and transparent areas which alternate with each other at intervals corresponding to the width of each of the subpixels,

wherein an area of the liquid crystal layer corresponding to each of the subpixels is divided into a liquid crystal area corresponding to each of the diffusing areas and a liquid crystal area corresponding to each of the transparent areas and transmittances of the liquid crystal areas are adjusted separately.

14. The liquid crystal display device of claim 13, wherein, in a public mode, an image with a wide viewing angle is formed by using light passing through the liquid crystal areas of the liquid crystal layer corresponding to the diffusing areas, and, in a private mode, an image with a narrow viewing angle is formed by not using light passing through the liquid crystal areas of the liquid crystal layer corresponding to the diffusing areas.

15. The liquid crystal display device of claim 14, wherein, in the public mode, light passing through the liquid crystal areas of the liquid crystal layer corresponding to the transparent areas is not used to form the image with the wide viewing angle.

16. The liquid crystal display device of claim 14, wherein, in the public mode, both the light passing through the liquid crystal areas of the liquid crystal layer corresponding to the transparent areas and the light passing through the liquid crystal areas of the liquid crystal layer corresponding to the diffusing areas are used to form an image.

17. The liquid crystal display device of claim 13, wherein a width of each of the diffusing areas is equal to or greater than a width of each of the transparent areas.

18. The liquid crystal display device of claim 13, wherein a ratio of the width of each of the diffusing areas to pitch of the diffusing areas ranges from 0.5 to 0.9.

19. The liquid crystal display device of claim 13, wherein the diffuser comprises diffusion parts formed of a transparent resin including a plurality of diffusing particles and arranged to be spaced apart from one another.

20. The liquid crystal display device of claim 13, wherein the liquid crystal layer is disposed between an upper transparent substrate and a lower transparent substrate,

wherein, the diffuser is formed on the top surface of the liquid crystal panel and the upper transparent substrate includes a thickness less than five times the width of each of the subpixels.

21. The liquid crystal display device of claim 13, wherein the backlight unit provides collimated light to the liquid crystal panel so that the full width at half maximum of luminance is in a range of ±

20′

.

22. The liquid crystal display device of claim 21, wherein the backlight unit comprises:

a light source;

a light guide plate which guides light emitted by the light source to the liquid crystal panel and comprises a prism formed on at least one of a top surface of the light guide plate and a bottom surface of the light guide plate; and

a reverse prism sheet disposed above the light guide plate.

23. The liquid crystal display device of claim 22, wherein prisms are arranged on the top surface and the bottom surface of the liquid guide plate in directions orthogonal to each other.

24. The liquid crystal display device of claim 21, wherein the backlight unit comprises:

a light source disposed in a reflector and comprising a reflective surface; and

a collimator comprising a plate-shaped member having a plurality of light transmitting areas through which light passes and a plurality of non-transmitting areas formed between the light transmitting areas,

wherein each of the light transmitting areas comprises at least one reflective surface inclined with respect to a plane direction of the plate-shaped member and a direction perpendicular to the plane direction.

25. The liquid crystal display device of claim 24, further comprising a diffusion plate disposed between the light source and the collimator.