Method for driving transflective liquid crystal display

• US 20040201560A1
• Filed: 08/18/2003
• Published: 10/14/2004
• Est. Priority Date: 04/09/2003
• Status: Active Grant

• Current Assignee: InnoLux Corporation
• Original Assignee: Industrial Technology Research Institute
• Inventors: Shen, Yuh-Ren, Chen, Ching-Yih
• Granted Patent: US 7,009,592 B2
• Time in Patent Office: Days
• US Class Current: 345/87
• 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 3/3659 the addressing of the pixel involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependant on signal of two data electrodes

Abstract

A method for driving a transflective LCD. In the present invention, the transflective LCD has a plurality of pixels arranged in a matrix, and each pixel includes a reflective cell and a transmission cell. The reflective cell and transmission cells are driven by different transistors. In the method of the present invention, all the first switching devices are turned on and the first driving voltages are then applied to the reflective cells in turn. After that, all the second switching devices are turned on and the second driving voltages are then applied to the transmission cells in turn. The first driving voltages are applied to the reflective cells in turn and the second driving voltages are applied to the transmission cells in turn in one frame period.

Claims

1. A method for driving a transflective LCD, wherein the transflective LCD has a plurality of pixels arranged in a matrix, each including a reflective cell and a transmission cell, the reflective cell having a first storage capacitor and a first active device, and the transmission cell having a second storage capacitor and a second active device, the method comprising the steps of:

providing first switching devices coupled between the reflective cells of the pixels and first driving voltages respectively;

providing second switching devices coupled between the transmission cells of the pixels and second driving voltages respectively;

turning on all the first switching devices and scanning the reflective cells in turn to apply the first driving voltages to the reflective cells in turn; and

turning on all the second switching devices and scanning the transmission cells in turn to apply the second driving voltages to the transmission cells in turn;

wherein the first driving voltages are applied to the reflective cells in turn and the second driving voltages are applied to the transmission cells in turn in one frame period.

2. The method as claimed in claim 1, wherein the first switching devices are turned on when the second switching devices are turned off, and the first switching devices are turned off when the second switching device is turned on.

3. The method as claimed in claim 1, further comprising a step of turning on all the first switching devices and second switching devices without scanning any pixel before the frame period.

4. A method for driving a transflective LCD, wherein the transflective LCD has a plurality of pixels arranged in a matrix, each pixel including a reflective cell and a transmission cell, the reflective cell having a first storage capacitor and a first active device and the transmission cell having a second storage capacitor and a second active device, the method comprising the steps of:

providing first switching devices coupled between the reflective cells of the pixels and first driving voltages respectively;

providing second switching devices coupled between the transmission cells of the pixels and second driving voltages respectively;

scanning each row of the pixels in turn in one frame period; and

turning on the first switching device and the second device at different times to apply the first driving voltage to the reflective cells and the second driving voltage to the transmission cells respectively, when each pixel row is scanned.

5. The method as claimed in claim 4, wherein reflective cells are turned on when the first switching devices and the second switching devices are turned on and off respectively.

6. The method as claimed in claim 4, wherein when transmission cells are turned on when the first switching devices and the second switching devices are turned off and on respectively.

7. The method as claimed in claim 6, further comprising a step of turning on all the first switching devices and second switching devices without scanning any pixel before the frame period.

8. A method for driving a transflective LCD, wherein the transflective LCD has a plurality of pixels arranged in a matrix, each pixel including a reflective cell and a transmission cell, the reflective cell having a first storage capacitor and a first active device and the transmission cell having a second storage capacitor and a second active device, the method comprising the steps of:

providing first switching devices coupled between the reflective cells of the pixels and first driving voltages respectively;

providing second switching devices coupled between the transmission cells of the pixels and second driving voltages respectively;

scanning each row of the pixels in turn in one frame period; and

turning on the first switching device and the second switching devices simultaneously to apply the first driving voltages to the reflective cells and the second driving voltage to the transmission cells simultaneously when each pixel row is scanned, wherein the second switching devices are turned off earlier than the first switching devices.

9. A method for driving a transflective LCD, wherein the transflective LCD has a plurality of pixels arranged in a matrix, each pixel including a reflective cell and a transmission cell, the reflective cell having a first storage capacitor and a first active device and the transmission cell having a second storage capacitor and a second active device, the method comprising the steps of:

providing first switching devices coupled between the reflective cells of the pixels and first driving voltages respectively;

providing second switching devices coupled between the transmission cells of the pixels and second driving voltages respectively; and

turning on the first switching devices to apply the first driving voltages to the reflective cells of the pixels and scanning each row of the pixels in turn simultaneously in one frame period.

10. A method for driving a transflective LCD, wherein the transflective LCD has a plurality of pixels arranged in a matrix, each pixel including a reflective cell and a transmission cell, the reflective cell having a first storage capacitor and a first active device and the transmission cell having a second storage capacitor and a second active device, the method comprising the steps of:

providing first switching devices coupled between the reflective cells of the pixels and first driving voltages respectively;

providing second switching devices coupled between the transmission cells of the pixels and second driving voltages respectively; and

turning on the second switching devices to apply the second driving voltages to the transmission cells of the pixels and scanning each row of the pixels in turn simultaneously in one frame period.