METHOD OF MODULATING A COMMON SIGNAL OF LIQUID CRYSTAL DISPLAY

• US 20100265002A1
• Filed: 07/02/2009
• Published: 10/21/2010
• Est. Priority Date: 04/17/2009
• Status: Abandoned Application

• Current Assignee: Chunghwa Picture Tubes Limited
• Original Assignee: Chunghwa Picture Tubes Limited
• Inventors: Yu, Liang-Ming, Hsu, Chao-Hui
• Application Number:
  US12/496,648
• Publication Number:
  US 20100265002A1
• Time in Patent Office: Days
• US Class Current: 332/117
• CPC Class Codes: G09G 2330/06 Handling electromagnetic interferences [EMI], covering emitted as well as received electromagnetic radiation
• CPC Class Codes: G09G 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors

Abstract

A driving circuit of LCD includes a common signal generator and a modulation circuit. The modulation circuit can generate a first frequency, a second frequency, and a third frequency. The common signal generator generates a swing common signal according to the first frequency, and modulates the frequency of the common signal in the frequency range between the second frequency and the third frequency.

Claims

1. A method for modulating a common signal of the LCD, the method comprising:

providing a first frequency;

generating a swing common signal according to the first frequency;

generating a second frequency and a third frequency according to the first frequency; and

modulating a frequency of the common signal in a frequency range between the second frequency and the third frequency.

2. The method of claim 1, wherein generating the swing common signal according to the first frequency comprises:

providing a high level voltage and a low level voltage; and

generating the swing common signal between the high level voltage and the low level voltage according to the first frequency.

3. The method of claim 1, wherein generating the second frequency and the third frequency according to the first frequency comprises:

generating the second frequency that is higher than the first frequency; and

generating the third frequency that is lower than the first frequency.

4. The method of claim 1, wherein modulating the frequency of the common signal in the frequency range between the second frequency and the third frequency comprises:

outputting the common signal of the third frequency in a first duration;

outputting the common signal of the first frequency in a second duration; and

outputting the common signal of the second frequency in a third duration.

5. The method of claim 1, further comprising:

adjusting a display signal of the LCD according to the modulated common signal.

6. A driving circuit of an LCD, comprising:

a common signal generator, for generating a swing common signal according to a high level voltage and a low level voltage; and

a modulation circuit, electrically connected to the common signal generator, for modulating frequency of the common signal.

7. The driving circuit of claim 6, wherein the LCD outputs a display signal according to the modulated common signal.

8. The driving circuit of claim 6, wherein the common signal generated by the common signal generator comprises a first frequency.

9. The driving circuit of claim 8, wherein the modulation circuit is utilized to generate a second frequency that is higher than the first frequency, and a third frequency that is lower than the first frequency.

10. The driving circuit of claim 9, wherein the modulation circuit is utilized to modulate frequency of the common signal in a frequency range between the second frequency and the third frequency.