Liquid crystal display

• US 7,524,099 B2
• Filed: 05/25/2005
• Issued: 04/28/2009
• Est. Priority Date: 05/31/2004
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Moon, Jong Won
• Primary Examiner(s): Husar; Stephen F
• Application Number:
  US11/136,830
• Publication Number:
  US 20060007101A1
• Time in Patent Office: 1,434 Days
• Field of Search: 362/19, 362/606, 362/607, 362/618, 345/87, 345/88, 345/102, 349/61, 349/62, 349/64
• US Class Current: 362/607
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133507 Films for enhancing the luminance
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

A liquid crystal display and method of reducing light leakage in a black mode of a liquid crystal display is provided. In the liquid crystal display, a backlight assembly generates light, and a display unit is disposed over the backlight assembly to display an image by using light received from the backlight assembly. A DBEF (dual brightness enhanced film) is attached to a lower polarization plate provided at the display unit. A brightness control plate is interposed between the lower polarization plate and the DBEF to reduce the brightness of an inclined incident light that is not perpendicular to an absorbing axis of the polarization plate.

Claims

1. An LCD (liquid crystal display) comprising:

a backlight assembly for generating light;

a display unit disposed over the backlight assembly to display an image by using light received from the backlight assembly, the display unit including a lower polarization plate;

a DBEF (dual brightness enhanced film) disposed under the lower polarization plate; and

a brightness control plate interposed between the lower polarization plate and the DBEF to reduce the brightness of an inclined incident light in a normally black mode that is not perpendicular to an absorbing axis of the polarization plate wherein the brightness control plate has a thickness of about 40 nm.

2. The display according to claim 1, wherein the brightness control plate comprises PC (polycarbonate) material.

3. The display according to claim 1, wherein the backlight assembly comprises:

a lamp unit for generating light; and

a light guide unit for guiding the light from the lamp unit toward the display unit.

4. The display according to claim 3, wherein the backlight assembly further comprises:

diffusion sheets disposed between the light guide unit and the display unit.

5. The display according to claim 1, wherein the display unit further comprises:

an LCD panel including a TFT substrate having an electrode formed thereon, a color filter substrate, and a liquid crystal layer injected between the TFT substrate and the color filter substrate; and

an upper polarization plate disposed over the LCD panel, the lower polarization plate disposed under the LCD panel.

6. The display according to claim 5, wherein the display unit further comprises the DBEF attached to the lower polarization plate through the brightness control plate.

7. A liquid crystal display comprising:

a backlight assembly for generating light;

a display unit disposed over the backlight assembly to display an image by using light received from the backlight assembly, the display unit having a lower polarization plate; and

a brightness control plate attached to the lower polarization plate to reduce the brightness of inclined incident light in a normally black mode that is not perpendicular to an absorbing axis of the polarization plate wherein the brightness control plate has a thickness of about 40 nm.

8. The display according to claim 7, wherein the brightness control plate comprises PC (polycarbonate) material.

9. The display according to claim 7, wherein the backlight assembly comprises:

a lamp unit for generating light; and

a light guide unit including diffusion sheets and a DBEF (dual brightness enhanced film) to guide the light from the lamp unit toward the display unit.

10. The display according to claim 9, wherein the backlight assembly further comprises:

the diffusion sheets disposed between the light guide unit and the display unit; and

the DBEF disposed between the diffusion sheets.

11. The display according to claim 7, wherein the display unit comprises:

an LCD panel including a TFT substrate having an electrode formed thereon, a color filter substrate, and a liquid crystal layer injected between the TFT substrate and the color filter substrate; and

an upper polarization plate disposed over the LCD panel, the lower polarization plate disposed under the LCD panel.

12. A method of reducing light leakage in a black mode of a liquid crystal display, the method comprising:

generating light;

polarizing the light through a polarizing plate; and

reducing a brightness of inclined incident light that is not perpendicular to an absorbing axis of the polarization plate prior to polarizing the light during the black mode of the liquid crystal display by a brightness control plate attached to the lower polarization plate,

wherein the brightness control plate has a thickness of about 40 nm.

13. The method according to claim 12, further comprising reflecting a reflected and lost portion of light transmitted toward the polarizing plate using a DBEF (dual brightness enhanced film).

14. The method according to claim 13, further comprising limiting a thickness of the DBEF to about 40 nm.

15. The method according to claim 12, further comprising using PC (polycarbonate) to reduce the brightness of the inclined incident light.