Detecting circuit for pixel electrode voltage of flat panel display device

• US 9,041,425 B2
• Filed: 05/04/2011
• Issued: 05/26/2015
• Est. Priority Date: 10/14/2010
• Status: Active Grant

• Current Assignee: Beihai HKC Optoelectronics Technology Company Limited
• Original Assignee: Shanghai Tianma Micro-Electronics Company Limited (Tianma Microelectronics Company Limited)
• Inventors: Huang, Zhongshou
• Primary Examiner(s): Phan, Huy Q
• Assistant Examiner(s): DICKINSON, DUSTIN R
• Application Number:
  US13/100,637
• Publication Number:
  US 20120091997A1
• Time in Patent Office: 1,483 Days
• Field of Search: 324/760.01, 324/760.02
• US Class Current: 324/760.01
• CPC Class Codes: G02F 1/1309 Repairing; Testing
• 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 2320/0223 Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal electrodes
• 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 detecting circuit for pixel electrode voltage of a flat panel display device, the flat panel display device having a plurality of scanning lines and a plurality of data lines crossing with the plurality of scanning lines, the plurality of scanning lines and data lines define a plurality of pixel units, and each of the pixel units including a pixel switching element and a pixel electrode. The detecting circuit for pixel electrode voltage includes at least one detecting sub-circuit for pixel electrode voltage. The detecting sub-circuit for pixel electrode voltage includes: a signal amplifying unit connected with the pixel electrode in the pixel unit, for amplifying a voltage signal of the pixel electrode; and a signal detecting unit connected with the signal amplifying unit, for detecting the voltage signal of the pixel electrode that has been amplified by the signal amplifying unit, and outputting a variation in the voltage signal of the pixel electrode with time. Compared with the prior art, the present invention has advantages of simple detecting circuit structure and accurate detection result.

Claims

1. A detecting circuit for pixel electrode voltage of a flat panel display device, wherein the flat panel display device has a plurality of scanning lines and a plurality of data lines crossing with the plurality of scanning lines, the plurality of scanning lines and the plurality of data lines define a plurality of pixel units, and each of the pixel units comprises a pixel switching element and a pixel electrode, the detecting circuit for pixel electrode voltage comprising:

at least one detecting sub-circuit for pixel electrode voltage, each of which comprising;

a signal amplifying unit connected with the pixel electrode in the pixel unit, for amplifying a voltage signal of the pixel electrode; and

a signal detecting unit connected with the signal amplifying unit, for detecting the amplified voltage signal of the pixel electrode from the signal amplifying unit, and outputting a variation in the voltage signal of the pixel electrode with time, wherein

the detecting circuit for pixel electrode voltage includes two detecting sub-circuits for pixel electrode voltage, and the pixel electrodes in first and last pixel units of a first row of pixel units of the flat panel display device are connected to the signal amplifying units of the two detecting sub-circuits for pixel electrode voltage respectively.

2. The detecting circuit for pixel electrode voltage of the flat panel display device according to claim 1, wherein the pixel switching element is a thin film transistor comprising:

a gate connected electrically to the scanning line, for controlling the thin film transistor to turn on or off;

a source connected electrically to the data line, for receiving a data signal; and

a drain connected electrically to the pixel electrode.

3. The detecting circuit for pixel electrode voltage of the flat panel display device according to claim 1, wherein the flat panel display device is in a frame inversion mode or a line inversion mode, and respective pixel electrodes in a row of pixel units of the flat panel display device are connected in parallel to the signal amplifying unit of one of the detecting sub-circuits for pixel electrode voltage.

4. The detecting circuit for pixel electrode voltage of the flat panel display device according to claim 3, wherein each of the pixel electrodes connected to the signal amplifying unit of each detecting sub-circuit for pixel electrode voltage is a dummy pixel electrode of the flat panel display device.

5. The detecting circuit for pixel electrode voltage of the flat panel display device according to claim 1, wherein the flat panel display device is in a dot inversion mode, and respective pixel electrodes of which the polarities vary uniformly in a row of pixel units of the flat panel display device are connected in parallel to the signal amplifying unit of one of the detecting sub-circuits for pixel electrode voltage.

6. The detecting circuit for pixel electrode voltage of the flat panel display device according to claim 5, wherein each of the pixel electrodes connected to the signal amplifying unit of each detecting sub-circuit for pixel electrode voltage is a dummy pixel electrode of the flat panel display device.

7. The detecting circuit for pixel electrode voltage of the flat panel display device according to claim 1, wherein each signal amplifying unit is a MOS transistor having a gate connected with the pixel electrode of the pixel unit.

8. The detecting circuit for pixel electrode voltage of the flat panel display device according to claim 7, wherein each detecting sub-circuit for pixel electrode voltage further comprises a preset unit located between the MOS transistor serving as the signal amplifying unit and the pixel electrode of the pixel unit connected thereto, for presetting characteristics of the MOS transistor.

9. The detecting circuit for pixel electrode voltage of the flat panel display device according to claim 8, wherein each preset unit is a MOS transistor having a drain connected with the gate of the MOS transistor serving as the signal amplifying unit.

10. The detecting circuit for pixel electrode voltage of the flat panel display device according to claim 1, wherein each signal amplifying unit is a source follower.

11. The detecting circuit for pixel electrode voltage of the flat panel display device according to claim 10, wherein each source follower comprises a first MOS transistor and a second MOS transistor, wherein a drain of the first MOS transistor serves as an input terminal connected with the pixel electrode, a source of the first MOS transistor is grounded, a drain of the first MOS transistor is connected with a drain of the second MOS transistor to serve as an output terminal, and a gate and a source of the second MOS transistor are both connected with a supply voltage.

12. The detecting circuit for pixel electrode voltage of the flat panel display device according to claim 11, wherein each source follower further comprises a preset terminal located at the gate of the first MOS transistor, for presetting characteristics of the source follower.

13. The detecting circuit for pixel electrode voltage of the flat panel display device according to claim 1, wherein the flat panel display device is a thin film transistor liquid crystal display device.

14. The detecting circuit for pixel electrode voltage of the flat panel display device according to claim 1, wherein the pixel electrode connected to the signal amplifying unit of each detecting sub-circuit for pixel electrode voltage is a dummy pixel electrode of the flat panel display device.