Liquid crystal display

• US 7,619,703 B2
• Filed: 12/09/2005
• Issued: 11/17/2009
• Est. Priority Date: 01/26/2005
• Status: Expired due to Fees

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Sang-Hoon, Yun, Young-Nam, Lee, Maung-Hi
• Primary Examiner(s): Nelms; David
• Assistant Examiner(s): NGUYEN, THANH NHAN P
• Application Number:
  US11/298,851
• Publication Number:
  US 20060164574A1
• Time in Patent Office: 1,439 Days
• Field of Search: 349/64, 349 74- 83, 349/96, 349/113, 349/114, 349/65, 349/67
• US Class Current: 349/113
• CPC Class Codes: G02F 1/133342 for double-sided displays
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

A liquid crystal display includes a backlight unit including a light source, a first panel unit disposed on a first side of the backlight unit, a second panel unit disposed on a second side of the backlight unit, and a porous reflector disposed between the backlight unit and the second panel unit and reflecting some light that is from the light source or is externally incident, and transmitting some.

Claims

1. A liquid crystal display comprising:

a backlight unit including a light source and a light guide plate;

a first panel unit disposed on a first side of the backlight unit;

a second panel unit disposed on a second side of the backlight unit;

a porous reflector disposed adjacent the light guide plate and formed separately from the light guide plate, the porous reflector reflecting light to illuminate the first panel unit and transmitting light to illuminate the second panel unit;

a first lower polarizer disposed between the first panel unit and the backlight unit and disposed under the first panel unit, wherein the first lower polarizer comprises a first polarizing film facing the backlight unit, and reflecting some of the light and transmitting some of the light; and

a second polarizing film that polarizes the transmitted light;

a first upper polarizer disposed opposite to the first lower polarizer; and

a diffusion member disposed on one side of the first lower polarizer.

2. The liquid crystal display of claim 1, wherein the porous reflector has a low density of reflective material that it reflects some of the light and transmits some of the light.

3. The liquid crystal display of claim 1, wherein the porous reflector comprises a patterned reflective plate including areas devoid of reflective material to allow light transmission.

4. The liquid crystal display of claim 1, further comprising:

an optical sheet disposed between the first lower polarizer and the light guide plate of the backlight unit.

5. The liquid crystal display of claim 1, wherein the first polarizing film and the second polarizing film are made as one film.

6. The liquid crystal display of claim 1, wherein the diffusion member comprises an adhesive including a scattering material.

7. The liquid crystal display of claim 1, wherein a ratio of transmittance to reflectance of the porous reflector ranges from 7:

3 to 6;

4.

8. A liquid crystal display, comprising:

a backlight unit including a light source and a light guide plate;

a first panel unit disposed on a first side of the backlight unit;

a second panel unit disposed on a second side of the backlight unit;

a porous reflector disposed adjacent the light guide plate and formed separately from the light guide plate, the porous reflector reflecting light to illuminate the first panel unit and transmitting light to illuminate the second panel unit;

a first lower polarizer disposed between the first panel unit and the backlight unit and disposed under the first panel unit;

a first upper polarizer disposed opposite to the first lower polarizer, comprising a polarizing film having a surface that is processed with a low reflective material; and

a diffusion member disposed on one side of the first lower polarizer.

9. A liquid crystal display, comprising:

a backlight unit including a light source and a light guide plate;

a first panel unit disposed on a first side of the backlight unit;

a second panel unit disposed on a second side of the backlight unit;

a porous reflector disposed adjacent the light guide plate and formed separately from the light guide plate, the porous reflector reflecting light to illuminate the first panel unit and transmitting light to illuminate the second panel unit;

a first lower polarizer disposed between the first panel unit and the backlight unit and disposed under the first panel unit; and

a first upper polarizer disposed opposite to the first lower polarizer wherein the first lower polarizer comprises a diffusion member includes an adhesive containing a scattering material.

10. A liquid crystal display, comprising:

a backlight unit including a light source and a light guide plate;

a first panel unit disposed on a first side of the backlight unit;

a second panel unit disposed on a second side of the backlight unit;

a porous reflector disposed adjacent the light guide plate and formed separately from the light guide plate, the porous reflector reflecting light to illuminate the first panel unit and transmitting light to illuminate the second panel unit;

a first lower polarizer disposed between the first panel unit and the backlight unit and disposed under the first panel unit; and

a first upper polarizer disposed opposite to the first lower polarizer wherein a low reflective layer is formed on a surface of the first lower polarizer facing the backlight unit.

11. A liquid crystal display, comprising:

a backlight unit including a light source and a light guide plate;

a first panel unit disposed on a first side of the backlight unit;

a second panel unit disposed on a second side of the backlight unit;

a porous reflector disposed adjacent the light guide plate and formed separately from the light guide plate, the porous reflector reflecting light to illuminate the first panel unit and transmitting light to illuminate the second panel unit;

thin film transistors, and transparent electrodes connected to the thin film transistors;

a first panel comprising storage electrodes for maintaining charged voltages in the transparent electrodes for a certain time; and

a second panel facing the first panel and comprising black matrices, color filters between the black matrices, and a common electrode,

wherein the storage electrodes are made of a reflective material and no color filters are provided over the storage electrodes.

12. A liquid crystal display comprising:

a backlight unit having a light source and a light guide plate;

a first panel unit disposed on a first side of the backlight unit;

a second panel unit disposed on a second side of the backlight unit;

a transflective sheet disposed adjacent the light guide plate and formed separately from the light guide plate, the transflective sheet reflecting light to illuminate the first panel unit transmitting light to illuminate the second panel unit;

a first lower polarizer disposed between the first panel unit and the backlight unit and disposed under the first panel unit, wherein the first lower polarizer comprises a first polarizing film facing the backlight unit, and reflecting some of the light and transmitting some of the light; and

a second polarizing film that polarizes the transmitted light;

a first upper polarizer disposed opposite to the first lower polarizer; and

a diffusion member disposed on one side of the first lower polarizer.

13. The liquid crystal display of claim 12, wherein the transflective sheet has a thickness of approximately λ

/2, where λ

/2 is a half-wavelength of the light to be reflected or transmitted.

14. The liquid crystal display of claim 13, wherein a ratio of transmittance to reflectance of the transflective sheet ranges from 7:

3 to 6;

4.

15. A liquid crystal display comprising:

a backlight unit including a light source and a light guide plate;

a first panel unit comprising an upper panel, a lower panel facing the upper panel, a first upper polarizer disposed on the upper panel, a first lower polarizer disposed under the lower panel, a diffusion member disposed on one side of the first lower polarizer, and a liquid crystal layer interposed between the first and second panels, retarding light passing therethrough by λ

/2, having a twisted nematic mode, and forming an angle of 90 degrees between liquid crystal adjacent to the upper panel and liquid crystal adjacent to the lower panel, wherein the first lower polarizer comprises a first polarizing film facing the backlight unit, and reflecting some of the light and transmitting some of the light, and a second polarizing film polarizing the transmitted light;

a second panel unit disposed under the first panel unit; and

a porous reflector disposed adjacent the light guide plate and formed separately from the light guide plate, the porous reflector reflecting light to illuminate the first panel unit and transmitting light to illuminate the second panel unit.

16. The liquid crystal display of claim 15, wherein the second panel unit comprises an upper panel, a lower panel facing the upper panel, and a liquid crystal layer interposed between the first and second panels, retarding light passing therethrough by λ

/2, having a twisted nematic mode, and forming an angle of 90 degrees between liquid crystal adjacent to the upper panel and liquid crystal adjacent to the lower panel.

17. The liquid crystal display of claim 15, wherein the porous reflector has a low density reflective material which reflects and transmits light.

18. The liquid crystal display of claim 15, wherein the porous reflector comprises a patterned reflective plate.

19. The liquid crystal display of claim 15, wherein the diffusion member comprises an adhesive containing a scattering material.

20. A liquid crystal display comprising:

a backlight unit including a light source and a light guide plate;

a first panel unit disposed on a first side of the backlight unit;

a second panel unit disposed on a second side of the backlight unit;

a porous reflector adjacent the light guide plate and formed separately from the light guide plate, the porous reflector having a plurality of holes so that it reflects light to illuminate the first panel unit and transmits light through the holes to illuminate the second panel unit;

a first lower polarizer disposed between the first panel unit and the backlight unit and disposed under the first panel unit, wherein the first lower polarizer comprises a first polarizing film facing the backlight unit, and reflecting some of the light and transmitting some of the light; and

a second polarizing film that polarizes the transmitted light;

a first upper polarizer disposed opposite to the first lower polarizer; and

a diffusion member disposed on one side of the first lower polarizer.

21. The liquid crystal display of claim 20, wherein the holes of the porous reflector are formed by patterning a photoresist provided on a reflective plate.

22. The liquid crystal display of claim 20, wherein a ratio of transmittance to reflectance of the porous reflector ranges from 7:

3 to 6;

4.

23. The liquid crystal display of claim 22, wherein a ratio of area of a reflective region and a hole region ranges from 7:

3 to 6;

4.