Liquid crystal display with polarizer having patterned layers of metal lines and retardation films

• US 7,750,995 B2
• Filed: 05/24/2006
• Issued: 07/06/2010
• Est. Priority Date: 06/24/2005
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Group)
• Original Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Inventors: Kim, Jae-Hyun
• Primary Examiner(s): Nelms; David
• Assistant Examiner(s): Merlin; Jessica M
• Application Number:
  US11/440,601
• Publication Number:
  US 20060290846A1
• Time in Patent Office: 1,504 Days
• Field of Search: 349113-115, 349/96, 349117-121
• US Class Current: 349/96
• CPC Class Codes: G02F 1/133541 Circular polarisers
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one
• CPC Class Codes: G02F 2203/01 transmissive
• CPC Class Codes: G02F 2203/09 transflective

Abstract

Disclosed is a liquid crystal display. In the LCD, a reflective polarizer and an optical retarder are provided between an absorbing polarizer and a backlight unit. This structure recycles light that would ordinarily be removed by absorption in conventional LCDs to be used for the display, so that light efficiency and display luminance of the LCD may be improved.

Claims

1. A liquid crystal display comprising:

a display panel;

a reflective polarizer provided under the display panel transmitting light that is linearly polarized in a first direction and reflecting light that is linearly polarized in a second direction perpendicular to the first direction; and

a backlight unit provided under the reflective polarizer, said backlight unit comprising a light source for supplying light to the display panel,

wherein the reflective polarizer includes a substrate, a plurality of metal lines, and a plurality of optical retardation films formed under the metal lines,

wherein the metal lines are parallel to each other in the second direction, and an interval between two adjacent metal lines is narrower than a wavelength of visible light supplied by the backlight unit;

wherein the plurality of optical retardation films are arranged to have substantially the same pattern as the metal lines in a plane view, and

wherein a material disposed within the interval between the two adjacent metal lines is the same as that disposed within the interval between the optical retardation films.

2. The liquid crystal display of claim 1, further comprising a first absorbing polarizer provided between the display panel and the reflective polarizer.

3. The liquid crystal display of claim 2, wherein a transmission axis of the first absorbing polarizer is in the first direction.

4. The liquid crystal display of claim 3, further comprising a second absorbing polarizer coupled to an upper surface of the display panel.

5. The liquid crystal display of claim 4, wherein a transmission axis of the second absorbing polarizer is in the second direction.

6. The liquid crystal display of claim 1, wherein each of the plurality of optical retardation films has a slow axis and a fast axis, and a phase difference between the two axes is a quarter-wave for converting circularly polarized light into linearly polarized light or linearly polarized light into circularly polarized light.

7. The liquid crystal display of claim 6, wherein the fast axis or the slow axis of the respective optical retardation film is formed at an angle of ±

45°

relative to the first direction or the second direction.

8. The liquid crystal display of claim 7, wherein the substrate of the reflective polarizer is placed on the plurality of metal lines or under the respective optical retardation film.

9. The liquid crystal display of claim 1, wherein the respective optical retardation film is obtained by curing liquid crystal.

10. The liquid crystal display of claim 1, wherein the backlight unit further includes a reflective plate for reflecting light toward the display panel.

11. The liquid crystal display of claim 1, wherein the plurality of optical retardation films are parallel to each other in the second direction, and an interval between two adjacent optical retardation films is the same as that between two adjacent metal lines.