Transreflective liquid crystal display apparatus with single cell-gap and reduced power consumption

• US 20070216821A1
• Filed: 09/19/2006
• Published: 09/20/2007
• Est. Priority Date: 12/21/2005
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Chul, Kim, Il
• Granted Patent: US 7,961,279 B2
• Time in Patent Office: Days
• US Class Current: 349/38
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/134345 Subdivided pixels, e.g. for grey scale or redundancy
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode

Abstract

A transreflective liquid crystal display (LCD) apparatus with a single cell gap is presented, along with a method of driving the apparatus. The apparatus operates with low power consumption because its electro-optical characteristics in a transmissive region and a reflective region are equalized. The transreflective LCD apparatus includes first and second liquid crystal cells formed respectively in transmissive and reflective regions of a first subpixel, first and second thin film transistors connected respectively to the first and second liquid crystal cells, and first and second storage capacitors connected respectively to the first and second liquid crystal cells.

Claims

1. A transreflective liquid crystal display apparatus, comprising:

first and second liquid crystal cells formed respectively in transmissive and reflective regions of a first subpixel;

first and second thin film transistors connected respectively to the first and second liquid crystal cells; and

first and second storage capacitors connected respectively to the first and second liquid crystal cells.

2. The transreflective liquid crystal display apparatus of claim 1, wherein capacitances of the first and second storage capacitors are different from each other.

3. The transreflective liquid crystal display apparatus of claim 2, wherein areas of first and second storage electrodes of the first and second storage capacitors are different from each other.

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

third and fourth liquid crystal cells formed respectively in transmissive and reflective regions of a second subpixel adjacent to the first subpixel;

third and fourth thin film transistors connected respectively to the third and fourth liquid crystal cells; and

third and fourth storage capacitors connected respectively to the third and fourth liquid crystal cells.

5. The transreflective liquid crystal display apparatus of claim 4, wherein capacitances of the third and fourth storage capacitors are different from each other.

6. The transreflective liquid crystal display apparatus of claim 5, wherein areas of third and fourth storage electrodes of the third and fourth storage capacitors are different from each other.

7. The transreflective liquid crystal display apparatus of claim 4, further comprising:

fifth and sixth liquid crystal cells formed respectively in transmissive and reflective regions of a third subpixel adjacent to the second subpixel;

fifth and sixth thin film transistors connected respectively to the fifth and sixth liquid crystal cells; and

fifth and sixth storage capacitors connected respectively to the fifth and sixth liquid crystal cells.

8. The transreflective liquid crystal display apparatus of claim 7, wherein capacitances of the fifth and sixth storage capacitors are different from each other.

9. The transreflective liquid crystal display apparatus of claim 8, wherein magnitudes of fifth and sixth storage electrodes of the fifth and sixth storage capacitors are different from each other.

10. The transreflective liquid crystal display apparatus of claim 7, wherein capacitances of the first, third and fifth storage capacitors are different from each other.

11. The transreflective liquid crystal display apparatus of claim 10, wherein areas of the first, third and fifth storage electrodes of the first, third and fifth storage capacitors are different from each other.

12. The transreflective liquid crystal display apparatus of claim 7, wherein capacitances of the second, fourth and sixth storage capacitors are different from each other.

13. The transreflective liquid crystal display apparatus of claim 12, wherein areas of second, fourth and sixth storage electrodes of the second, fourth and sixth storage capacitors are different from each other.

14. The transreflective liquid crystal display apparatus of claim 7, wherein cell gaps of the first to sixth liquid crystal cells are the same.

15. The transreflective liquid crystal display apparatus of claim 7, further comprising:

a plurality of gate lines and a plurality of data lines intersecting each other to define the first to third subpixels; and

a storage line formed alternately with the plurality of gate lines and connected to the first to sixth storage capacitors.

16. The transreflective liquid crystal display apparatus of claim 15, wherein a storage voltage of the storage line is applied by line inversion, and the storage voltage swings during a period while a gate OFF voltage is applied to the gate lines.

17. A method of driving a transreflective liquid crystal display apparatus, comprising the steps of:

charging first and second liquid crystal cells to respective capacitances, wherein the first and second liquid crystal cells are formed in transmissive and reflective regions of a first subpixel, respectively;

charging first and second storage capacitors to respective capacitances, wherein the first and second storage capacitors are connected to the first and second liquid crystal cells, respectively;

swinging a storage voltage of a storage line connected to the first and second storage capacitors; and

bootstrapping a transmissive voltage of a first transmissive electrode of the first liquid crystal cell and a reflective voltage of a first reflective electrode of the second liquid crystal cell by different bootstrap voltages.

18. The method of claim 17, wherein the storage voltage is applied by line inversion.

19. The method of claim 17, wherein the swinging a storage voltage is swinging the storage voltage during a period while the first and second thin film transistors connected respectively to the first and second liquid crystal cells are turned off.

20. The method of claim 17, further comprising the steps of:

charging third and fourth liquid crystal cells to respective capacitances, wherein the third and fourth liquid crystal cells are formed in transmissive and reflective regions, respectively, of a second subpixel adjacent to the first subpixel;

charging third and fourth storage capacitors to respective capacitances, wherein the third and fourth storage capacitors are connected to the third and fourth liquid crystal cells, respectively, and to the storage line;

bootstrapping a transmissive voltage of a second transmissive electrode of the third liquid crystal cell and a reflective voltage of a second reflective electrode of the fourth liquid crystal cell by different bootstrap voltages;

charging fifth and sixth liquid crystal cells to have respective capacitances, wherein the fifth and sixth liquid crystal cells are formed in transmissive and reflective regions, respectively, of a third subpixel adjacent to the second subpixel;

charging fifth and sixth storage capacitors to respective capacitances, wherein the fifth and sixth storage capacitors are connected to the fifth and sixth liquid crystal cells, respectively, and to the storage line; and

bootstrapping a transmissive voltage of a third transmissive electrode of the fifth liquid crystal cell and a reflective voltage of a third reflective electrode of the sixth liquid crystal cell by different bootstrap voltages.