Liquid crystal display

• US 7,548,293 B2
• Filed: 04/21/2005
• Issued: 06/16/2009
• Est. Priority Date: 05/25/2004
• Status: Active Grant

• Current Assignee: TCL China Star Optoelectronics Technology Co. Ltd. (TCL Technology Group Corp.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Jeong-ye, Rho, Soo-guy, Kim, Sang-il, Hong, Mun-pyo, Hong, Wang-su
• Primary Examiner(s): Kim; Richard H
• Application Number:
  US11/111,408
• Publication Number:
  US 20060007087A1
• Time in Patent Office: 1,517 Days
• Field of Search: 349/114
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133371 Cells with varying thickness of the liquid crystal layer
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 2203/09 transflective
• CPC Class Codes: G09G 2300/0456 with a reflective area and a transmissive area combined in one pixel, such as in transflectance pixels
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A semi-transmission liquid crystal display comprising a liquid crystal panel; a backlight unit to emit light to the liquid crystal panel; and a data driver to apply a data voltage to a data line of the liquid crystal panel; wherein, the liquid crystal panel comprises a TFT substrate which has a transmission area transmitting light from the backlight unit and a reflection area reflecting light from exterior, a color filter substrate which has color filter layer having a concave area which is formed corresponding to the reflection area, and a liquid crystal layer which is sandwiched between the TFT substrate and the color filter substrate and having varying thickness according to the concave area; and the data driver applies the data voltage to the data line in the liquid crystal panel by a transmission voltage mode when the backlight unit is on and by a reflection voltage mode when the backlight unit is off, which configuration provides a semi-transmission LCD having good display quality without an overcoat layer flattening a color filter layer.

Claims

1. A semi-transmission liquid crystal display comprising

a liquid crystal panel;

a backlight unit to emit light to the liquid crystal panel; and

a data driver to apply a data voltage to a data line of the liquid crystal panel;

wherein, the liquid crystal panel comprises a TFT substrate which has a transmission area transmitting light from the backlight unit and a reflection area reflecting light from exterior, a color filter substrate which comprises a color filter layer having a concave area which is formed corresponding to the reflection area, and a liquid crystal layer which is sandwiched between the TFT substrate and the color filter substrate and having varying thickness according to the concave area; and

the data driver applies the data voltage to the data line in the liquid crystal panel by a transmission voltage mode when the backlight unit is on and by a reflection voltage mode when the backlight unit is off,

wherein the thickness of the liquid crystal layer is thicker in the reflection area than in the transmission area.

2. The semi-transmission liquid crystal display according to claim 1, wherein the color filter substrate further comprises an insulating substrate disposed under the color filter layer, a common electrode layer disposed on the color filter layer, and an orientation layer disposed on the common electrode layer;

wherein the common electrode layer and the orientation layer have a shape conformal to the concave area of the color filter layer.

3. The semi-transmission liquid crystal display according to claim 1, wherein a highest voltage of the data voltage in the reflection voltage mode is determined by measuring reflectance as a function of the data voltage.

4. The semi-transmission liquid crystal display according to claim 3, wherein the highest value of the data voltage in the reflection voltage mode is in a range of ±

5% of the data voltage which shows a highest reflectance.

5. The semi-transmission liquid crystal display according to claim 3, wherein a gamma voltage which is added to the data voltage and controls a gamma characteristic is adjusted after determining the highest value of the data voltage in the reflection voltage mode.

6. The semi-transmission liquid crystal display according to claim 1, wherein the liquid crystal layer is in a vertically aligned (VA) mode.

7. The semi-transmission liquid crystal display according to claim 1, wherein the color filter layer has a hole in the concave area.

8. The semi-transmission liquid crystal display according to claim 1 wherein the thickness of the liquid crystal layer varies according to its position.

17. The semi-transmission liquid crystal display according to claim 2 wherein the common electrode layer is in contact with the color filter layer.

9. A semi-transmission liquid crystal display comprising

a liquid crystal panel;

a backlight unit to emit light to the liquid crystal panel; and

a data driver to apply a data voltage to a data line of the liquid crystal panel;

wherein, the liquid crystal panel comprises a TFT substrate which has a transmission area transmitting light from the backlight unit and a reflection area reflecting light from exterior, a color filter substrate which comprises a color filter layer having a concave area which is formed corresponding to the reflection area, and a liquid crystal layer which is sandwiched between the TFT substrate and the color filter substrate and having varying thickness according to the concave area; and

the data driver applies the data voltage to the data line in the liquid crystal panel by a transmission voltage mode when the backlight unit is on and by a reflection voltage mode when the backlight unit is off,

wherein a difference between a cellgap of a concave area of the color filter layer and a cellgap of a non-concave area is substantially the thickness of the color filter layer.

10. A semi-transmission liquid crystal display comprising

a liquid crystal panel;

a backlight unit to emit light to the liquid crystal panel; and

a data driver to apply a data voltage to a data line of the liquid crystal panel;

wherein, the liquid crystal panel comprises a TFT substrate which has a transmission area transmitting light from the backlight unit and a reflection area reflecting light from exterior, a color filter substrate which comprises a color filter layer having a concave area which is formed corresponding to the reflection area, and a liquid crystal layer which is sandwiched between the TFT substrate and the color filter substrate and having varying thickness according to the concave area; and

the data driver applies the data voltage to the data line in the liquid crystal panel by a transmission voltage mode when the backlight unit is on and by a reflection voltage mode when the backlight unit is off,

wherein the thickness of the color filter layer is between about 1 to about 1.5 μ

m, the thickness of the liquid crystal layer in a non-concave areas is between about 3 to about 4 μ

m, and the thickness of the liquid crystal layer in a concave area is between about 4 to about 5.5 μ

m.

11. A semi-transmission liquid crystal display comprising

a liquid crystal panel;

a backlight unit to emit light to the liquid crystal panel; and

a data driver to apply a data voltage to a data line of the liquid crystal panel;

wherein, the liquid crystal panel comprises a TFT substrate which has a transmission area transmitting light from the backlight unit and a reflection area reflecting light from exterior, a color filter substrate which comprises a color filter layer having a concave area which is formed corresponding to the reflection area, and a liquid crystal layer which is sandwiched between the TFT substrate and the color filter substrate and having varying thickness according to the concave area; and

the data driver applies the data voltage to the data line in the liquid crystal panel by a transmission voltage mode when the backlight unit is on and by a reflection voltage mode when the backlight unit is off,

wherein an average cellgap of the reflection area is larger than that of the trasmission area.

12. A semi-transmission liquid crystal display comprising

a liquid crystal panel;

a backlight unit to emit light to the liquid crystal panel; and

a data driver to apply a data voltage to a data line of the liquid crystal panel;

wherein, the liquid crystal panel comprises a TFT substrate which has a transmission area transmitting light from the backlight unit and a reflection area reflecting light from exterior, a color filter substrate which comprises a color filter layer having a concave area which is formed corresponding to the reflection area, and a liquid crystal layer which is sandwiched between the TFT substrate and the color filter substrate and having varying thickness according to the concave area; and

the data driver applies the data voltage to the data line in the liquid crystal panel by a transmission voltage mode when the backlight unit is on and by a reflection voltage mode when the backlight unit is off,

wherein a cellgap is substantially uniform except for at the concave area.

13. The semi-transmission liquid crystal display according to claim 12 wherein the TFT substrate has a top surface having a substantially uniform height.

14. The semi-transmission liquid crystal display according to claim 13 wherein a cell gap in the reflection area except for at the concave area is substantially the same as a cell gap in the transmission area.

15. The semi-transmission liquid crystal display according to claim 14 wherein the TFT substrate comprises a pixel electrode disposed in the reflection area and the transmission area and a reflection layer disposed in the reflection area.

16. The semi-transmission liquid crystal display according to claim 15 wherein the TFT substrate further comprises a protection layer disposed under the pixel electrode and the reflection layer and having a top surface that has a uniform height in the reflection area and in the transmission area.