LCD having a polarization or diffusion plate with an irregularly coated first opaque material and a black matrix of a second opaque material

• US 5,691,788 A
• Filed: 01/11/1996
• Issued: 11/25/1997
• Est. Priority Date: 01/06/1995
• Status: Expired due to Term

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Dong-gyu
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): MALINOWSKI, WALTER J
• Application Number:
  US08/586,462
• Time in Patent Office: 684 Days
• Field of Search: 359/40, 359/41, 359/48, 359/49, 359/63, 359/69, 349/64, 349/110, 349/112, 349/96
• US Class Current: 349/96
• 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 liquid crystal display with an improved viewing angle is disclosed which prevents gray scale inversion within a range of 60° in every direction because the change of a gray level according to the viewing angle is small. Light transmitted through the liquid crystal is scattered by a diffusion plate so that the brightness in front can be improved instead of narrowing the viewing angle, or uniform screen quality can be obtained by widening the viewing angle. The diffusion coefficient of the diffusion plate can be easily controlled. Further, it is possible to prevent a decrease in contrast due to external ambient light by screen-printing a black matrix pattern or atomizing a black dye on the diffusion plate.

Claims

1. A liquid crystal display (LCD), comprising:

a backlight;

a liquid crystal cell;

a diffusion plate for diffusing light after passing through said liquid crystal cell, said diffusion plate being made of a transparent plate on which transparent material is coated ruggedly;

first opaque material irregularly coated with a predetermined density on said diffusion plate; and

a black matrix of second opaque material printed on said diffusion plate with a pattern corresponding to a shape of said liquid crystal cell.

2. The LCD of claim 1, wherein said transparent plate comprises acrylic resin.

3. The LCD of claim 1, further comprising light means for causing the light emitted from said backlight to become parallel.

4. The LCD of claim 3, wherein said light means includes a prism.

5. The LCD of claim 4, wherein said light means further includes a microlens array.

6. The LCD of claim 5, wherein said liquid crystal cell includes upper and lower substrates with liquid crystal material sealed therebetween, and wherein said microlens array is formed in said lower substrate of said liquid crystal cell.

7. The LCD of claim 4, wherein an angle of said prism is 80°

to 100°

.

8. A polarization plate for a liquid crystal display (LCD), comprising:

a polarizer;

a diffusion plate for diffusing light attached to said polarizer, said diffusion plate being a transparent plate on which transparent material is ruggedly coated; and

first opaque material irregularly coated with a predetermined density on said diffusion plate; and

a black matrix of second opaque material printed on said diffusion plate with a pattern corresponding to a shape of a liquid crystal cell.

9. The polarization plate of claim 8, wherein said transparent plate comprises acrylic resin.

10. The polarization plate of claim 8, further comprising a protection layer for covering said polarizer and said diffusion plate, and being made of transparent insulating material for protecting said polarizer and said diffusion plate.

11. A liquid crystal display (LCD), comprising:

a backlight;

an liquid crystal cell; and

a polarization plate disposed on a side of said liquid crystal cell opposite said backlight, said polarization plate including;

a diffusion plate for diffusing light passing through said liquid crystal cell, said diffusion plate being made of a transparent plate on which transparent material is ruggedly coated; and

first opaque material irregularly coated with a predetermined density on said diffusion plate; and

a black matrix of second opaque material printed on said diffusion plate with a pattern corresponding to a shape of said liquid crystal cell.

12. The LCD of claim 11, wherein said diffusion plate is made of acrylic resin.

13. The LCD of claim 11, further comprising light means for causing light to be emitted from said backlight in parallel.

14. The LCD of claim 13, wherein said light means includes a prism.

15. The LCD of claim 14, wherein said light means further includes a microlens array.