Method for illuminating liquid crystal display device, a back-light assembly for performing the same, and a liquid crystal display device using the same

• US 7,710,513 B2
• Filed: 05/22/2008
• Issued: 05/04/2010
• Est. Priority Date: 06/07/2000
• Status: Expired due to Term

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Jeong-Hwan, Lee, Ik-Soo, Kim, Kyu-Seok, Won, Jong-Ho
• Primary Examiner(s): Nguyen; Dung
• Assistant Examiner(s): DUONG, TAI V
• Application Number:
  US12/125,674
• Publication Number:
  US 20090015752A1
• Time in Patent Office: 712 Days
• Field of Search: 349/57, 349 61- 65, 349/95, 359/599, 359/625, 359/640, 362/26, 362/600, 362/606, 362/611, 362/607
• US Class Current: 349/64
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

A method for illuminating a liquid crystal display device, a back-light assembly for performing the same and a liquid crystal display device using the same can improve the front luminance and production yield. Lights from a lamp is incident to a LCD panel side, which are then primarily diffused for a uniformity of the luminous flux of the incident lights. The luminous flux of the primarily diffused lights is condensed with respect to a first orientation component on a plane in parallel with the LCD panel, and then partially and secondarily diffused for extending a view angle of pixels of the LCD panel. After the luminous flux of the secondarily diffused lights is condensed with respect to a second orientation component perpendicular to the first orientation on the parallel plane, the condensed lights are illuminated onto the LCD panel. A diffusion sheet for secondarily diffusing the luminous flux and a condensing sheet for condensing the second orientation component are formed by a single sheet to reduce the manufacturing process of the liquid crystal display device. Also, a defect produced from respective sheets is minimized to enhance the yield.

Claims

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

an LCD panel;

a light source;

a diffuser formed between the LCD panel and the light source;

a condenser formed between the LCD panel and the diffuser; and

a high luminance condensing sheet formed between the LCD panel and the condenser,

wherein the high luminance condensing sheet comprises a transparent sheet having a predetermined thickness, a diffusion layer formed at the lower surface of the transparent sheet, and a condensing layer formed at the upper surface of the transparent sheet.

2. The LCD of claim 1, wherein the diffusion layer comprises a plurality of beads formed for uniformly diffusing the lights incident from the condenser.

3. The LCD of claim 1, wherein at least one of the condenser and the condensing layer are comprised of a plurality of prisms arranged in parallel with one another in a direction for condensing the lights incident from the diffuser and the diffusion layer.

4. The LCD of claim 1, wherein at least one of the condenser and the condensing layer are formed by arranging prisms to cross one another at a predetermined angle.

5. The LCD of claim 3, wherein a vertex portion of the prisms of the condensing layer adjacent to the LCD panel are rounded.

6. The LCD of claim 4, wherein a vertex portion of the prisms of the condensing layer adjacent to the LCD panel are rounded.

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

an LCD panel;

a light source;

a diffuser formed between the LCD panel and the light source; and

a condenser formed between the LCD panel and the diffuser,

wherein the diffuser comprises a plurality of beads formed on a surface of the diffuser adjacent to the light source distributed to have a smaller density than a plurality of beads formed on a surface of the diffuser adjacent to the condenser so that the surface of the diffuser adjacent to the condenser has a haze value that is larger than that of the surface of the diffuser adjacent to the light source.

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

an LCD panel;

a light source;

a diffuser formed between the LCD panel and the light source; and

a condenser formed between the LCD panel and the diffuser,

wherein the diffuser comprises a plurality of beads formed on at least a surface of the diffuser adjacent to the light source and a surface of the diffuser adjacent to the condenser, and

the plurality of beads are distributed to have a higher density at the surface of the diffuser adjacent to the condenser than that at the surface of the diffuser adjacent to the light source.

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

an LCD panel;

a light source;

a diffuser formed between the LCD panel and the light source;

a condenser formed between the LCD panel and the diffuser; and

a high luminance condensing sheet formed between the LCD panel and the condenser,

wherein the diffuser comprises a plurality of beads formed on a surface of the diffuser adjacent to the light source distributed to have a smaller density than a plurality of beads formed on a surface of the diffuser adjacent to the condenser so that the surface of the diffuser adjacent to the condenser has a haze value that is larger than that of the surface of the diffuser adjacent to the light source.