Driving system for active matrix liquid crystal display

• US 5,648,793 A
• Filed: 01/08/1992
• Issued: 07/15/1997
• Est. Priority Date: 01/08/1992
• Status: Expired due to Term

• Current Assignee: AmTRAN Technology Co., Ltd.
• Original Assignee: Industrial Technology Research Institute
• Inventors: Chen, Yen-Chen
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): Mengistu, Amare
• Application Number:
  US07/818,132
• Time in Patent Office: 2,015 Days
• Field of Search: 340/784, 340/805, 359/84, 359/85, 345/94, 345/100, 345/96, 345/209
• US Class Current: 345/96
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• 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 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• 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 system for matrix liquid crystal display in which the picture elements in adjacent rows and/or adjacent columns are applied with signals of opposite polarities. These polarities are reversed for every other field of a picture frame. Such a system reduces flicker and cross-talk. The system is implemented by interleaving the precharging and charging signals of adjacent picture elements.

Claims

1. An active matrix display system using picture elements (pixel) arranged in a X-Y matrix with m rows and n columns, comprising:

means for displaying a particular one of said pixels using X-Y coincident addressing of data signals and drive signals,

a plurality of column electrodes having said data signals impressed,

a plurality of row electrodes having said drive signals impressed,

said drive signals sequentially scanning one of said rows to apply said data signals on said column electrodes to display pixels where said data signals and said drive signals are coincident,

a plurality of switches, each having an input electrode, an output electrode and a control electrode, placed at cross-points of the column electrodes and the row electrodes,

said switches having said row electrodes as said control electrodes, said column electrodes as said input electrodes of said switches, and said pixels connected to the output electrodes of said switches,

said data signals having first polarities on odd-numbered said rows, and said data signals having polarities opposite to said first polarities on even-numbered rows.

2. A picture display system as described in claim 1, wherein said pixels are liquid crystals.

3. A picture display system as described in claim 1, wherein said switches are thin film field effect transistors with gates as said control electrodes, sources as said input terminals and drains as said output terminals.

4. A picture display system as described in claim 1, wherein said drive signals have double pulses for each scan line spaced by one dwell time of each said line,

said double pulses appearing on each successive said row are delayed by one said dwell time,

polarity of said data signal is reversed for adjacent said rows to effect row inversion.

5. A picture display system as described in claim 4, wherein said polarity of said data signal is reversed for every other field of said picture frame.

6. A picture display system as described in claim 1, wherein said drive signals have double pulses for each scan line spaced by one dwell time of each said line,

said double pulses appearing on each successive said row are delayed by one said dwell time,

polarity of said data signal is reversed for adjacent said row and adjacent said pixel on same row to effect dot inversion.

7. A picture display system as described in claim 6, wherein said polarity of said data signal is reversed for every other field of said picture frame.

8. A picture display system as described in claim 1, wherein said drive signal are pulses of longer duration than a dwell time of a line for precharging and charging a particular pixel,

said pulses are delayed by one said dwell time for successive rows,

said pixels have first common return paths for pixels of odd numbered rows and a second common return paths for pixels of even numbered rows,

said first common return paths and second common return paths having complementary control voltages during one horizontal scan and having said complementary control voltages reversed during next horizontal scan to effect row inversion.

9. A picture display system as described in claim 8, wherein said complementary control voltages are reversed for every other field of said picture frame.