Method for driving a liquid crystal display apparatus and driving circuit therefor

• US 6,366,271 B1
• Filed: 08/04/1998
• Issued: 04/02/2002
• Est. Priority Date: 11/13/1997
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Nishimura, Masaru, Kohno, Yasuhiko
• Primary Examiner(s): WU, XIAO MIN
• Application Number:
  US09/128,761
• Time in Patent Office: 1,337 Days
• Field of Search: 345/96, 345/209, 345/87, 345/88, 345/89, 345/98, 345/99, 345/100, 345/103, 345/208, 345/210, 345/95, 345/94, 345/97
• US Class Current: 345/103
• CPC Class Codes: G09G 2310/0281 Arrangement of scan or data electrode driver circuits at the periphery of a panel not inherent to a split matrix structure
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

Method for driving LCD device comprises step of: applying one of upper image signal outputted from an upper liquid crystal drive circuit and lower image signal outputted from a lower liquid crystal drive circuit to a plurality of pixels of a selected line by scanning signal outputted from a scanning signal circuit out of the plurality of pixels disposed in matrix to display a predetermined image; wherein there exist in mixture a case where the polarities of the upper image signal and the lower image signal are inverted every one vertical period and a case where the same polarity is maintained. The driving circuit of LCD device of the present invention includes a vertical synchronization signal converting circuit so as to obtain upper image signal and lower image signal.

Claims

1. A method of driving an LCD device comprising a step of:

applying one of an upper image signal outputted from an upper liquid crystal drive circuit and a lower image signal outputted from a lower liquid crystal drive circuit to a plurality of pixels of a selected line by a scanning signal outputted from a scanning signal circuit out of a plurality of pixels disposed in a matrix to display a predetermined image;

wherein, in the applying step, a mixture of two cases exists;

a first case in which a polarity of said upper image signal and a polarity of said lower image signal are inverted with respect to each other in the unit of one vertical period; and

a second case in which the polarity of said upper image signal and the polarity of said lower image signal are not inverted with respect to each other.

2. The method of claim 1, wherein said upper image signal is applied to every other pixel out of said plurality of pixels constituting a selected line and said lower image signal is applied to each remaining pixel.

3. The method of claim 2, wherein every other pixel is a pixel of odd number, and the remaining pixels are pixels of even number.

4. A method of driving an LCD device comprising a step of:

applying one of an upper image signal outputted from an upper liquid crystal drive circuit and a lower image signal outputted from a lower liquid crystal drive circuit to a plurality of pixels of a selected line by a scanning signal outputted from a scanning signal circuit out of a plurality of pixels disposed in a matrix to display a predetermined image;

wherein, in selecting a first line in each frame, polarities of said upper image signal and said lower image signal are changed every two frames, and timing for changing polarity of said upper image signal is displaced at a rate of one frame to timing for changing polarity of said lower image signal.

5. The method of claim 4, wherein said upper image signal is applied to every other pixel out of said plurality of pixels of a selected line and said lower image signal is applied to the remaining pixels.

6. The method of claim 5, wherein every other pixel is a pixel of odd number, and the remaining pixels are pixels of even number.

7. A driving circuit for an LCD device comprising at least an upper liquid crystal drive circuit, a lower liquid crystal drive circuit, a scanning signal circuit, a timing control circuit and a vertical synchronization signal converting circuit, said vertical synchronization signal converting circuit outputting a switching timing signal for a first polarity inversion signal and a switching timing signal for a second polarity inversion signal, wherein said switching timing signal for a first polarity inversion signal and said switching timing signal for a second polarity inversion signal are outputted by said vertical synchronization signal converting circuit such that in n frame polarity of a first polarity inversion signal inputted to said upper liquid crystal drive circuit is made inverted to polarity of a second polarity inversion signal inputted to said lower liquid crystal drive circuit;

and in n+1 frame said polarity of a first polarity inversion signal inputted to said upper liquid crystal drive circuit is in the same polarity as said polarity of a second polarity inversion signal inputted to said lower liquid crystal drive circuit.

8. The driving circuit for the LCD device of claim 7, wherein said vertical synchronization signal converting circuit comprises a differential circuit, a plurality of flip-flops and a plurality of NOT gates.