The present invention relates to a field of liquid crystal display, and in particular to a liquid crystal display panel and an adjusting method thereof.
As compared with a traditional Cathode Ray Tube (CRT) display, a liquid crystal display (LCD) has a lot of advantages, such as space saving, power saving and so on. The liquid crystal display with large size and high definition has already been widely used in replacement of the traditional cathode ray tube display. However, the larger the size of the LCD is, the more serious flicker phenomenon of the LCD will be.
An approach to drive the liquid crystal display is Alternate Current (AC) driving, and a data signal is alternately varied between a positive region and a negative region.
On or off state of the transistor 20 is controlled by a scan signal over the scan line 21. When the transistor 20 is turned on, a data signal over the data line 22 is transmitted to the liquid crystal capacitor 24 and the storage capacitor 25. Because each scan line 21 has a certain impedance, a plurality of liquid crystal capacitors 24, storage capacitors 25 and parasitic capacitances generated by a plurality of transistors 20, transmission of the scan signal over the scan line 21 will be influenced. A waveform of the scan signal may be distorted due to impedance effect and capacitance effect, thus variations of pixel voltages stored in the liquid crystal capacitors 24 of pixels on the same scan line may differ.
The larger the size of the liquid crystal display panel is, the longer the scan line 21 is, and correspondingly impedance of the scan line is also increased. The higher the definition of the liquid crystal display panel is, the more cross points between the scan lines 21 and the data lines 22 are, the more parasitic capacitances on the scan lines 21 are, and correspondingly parasitic capacitance of each scan line 21 is also increased. So during transmission of the scan signal over the scan line 21, the scan signal is affected greatly due to impedance effect and capacitance effect, the difference in variations of pixel voltages is exacerbated, and feedthrough voltages of pixel voltages may have different variation amounts at different pixels on the same scan line 21.
The invention is to provide a liquid crystal display panel, an adjusting method thereof and a liquid crystal display, which can reduce effectively flicker of the liquid crystal display panel and improve comfortableness of a user when viewing.
The invention relates to a liquid crystal display panel comprising scan lines and data lines arranged in a matrix, display units disposed at which the scan lines cross with the data lines, a data driver coupled with the data lines, a scan driver coupled with the scan lines, and an adjusting device. The adjusting device is configured to transmit a recovery voltage signal having a recovery voltage to a common electrode line corresponding to a scan line when a low-voltage scan signal is transmitted to the scan line, and form an adjusted voltage lower than the recovery voltage on the common electrode line when a high-voltage scan signal is transmitted to the scan line.
The invention also relates to an adjusting method of a liquid crystal display panel comprising steps of: transmitting a scan signal in sequence to each scan line; forming an adjusted voltage signal on a corresponding common electrode line when a high-voltage scan signal is transmitted to the scan line; transmitting to the common electrode line, a recovery voltage signal having a recovery voltage higher than a voltage of the adjusted voltage signal when a low-voltage scan signal is transmitted to a scan line; and compensating positively for a feedthrough voltage by a coupled voltage resulting from a voltage of the common electrode line and a pixel electrode on the scan line.
The invention still relates to a liquid crystal display comprising scan lines and data lines arranged in a matrix, a plurality of common electrode lines, a data driver coupled with the data lines, a scan driver coupled with the scan lines, and an adjusting device. The adjusting device is configured to transmit a recovery voltage signal having a recovery voltage to a corresponding common electrode line when a low-voltage scan signal is transmitted to a scan line, and form an adjusted voltage lower than the recovery voltage on the common electrode line when a high-voltage scan signal is transmitted to the scan line.
During transmission over the scan line, the voltage on the common electrode line is also subject to impedance effect and capacitance effect in a similar way to the scan signal, a coupled voltage resulting from the voltage on the common electrode line and a pixel electrode may just compensate for ΔVpd, a variation of a feedthrough voltage ΔVp, so that the variations of the feedthrough voltages ΔVp, ΔVpd, at different locations of the same scan line may be reduced, thereby reducing flicker of the liquid crystal display panel and improving comfortableness of a user when viewing.
The invention will be described in details hereinafter with reference to the accompanying drawings and preferred embodiments to make the above objects, features and advantages of the invention more apparent.
Referring to
The liquid crystal display panel in accordance with an embodiment of the present invention further comprises an adjusting device 27 (as shown is
The adjusting device is configured to transmit a recovery voltage signal having a recovery voltage to a common electrode line corresponding to a scan line when a low-voltage scan signal is transmitted to the scan line, and form an adjusted voltage lower than the recovery voltage on the common electrode line when a high-voltage scan signal is transmitted to the scan line. The adjusting device 27 includes a first adjusting unit 271 and a second adjusting unit 272. Output terminals of the first adjusting unit 271 and the second adjusting unit 272 of the adjusting device 27 are both connected with the start terminal of the common electrode line. The first adjusting unit 271 is in operation to transmit a low voltage signal to a common electrode line 23 corresponding to a certain scan line from the start terminal of the common electrode line 23 when a high-voltage scan signal is transmitted to the scan line 21. The second adjusting unit 272 is configured to transmit a recovery voltage signal to the common electrode line 23 when either a high-voltage scan signal or a low-voltage scan is transmitted to the scan line, that is, the second adjusting unit 272 is always in operation. So the adjusted voltage is formed on the common electrode line by the first and the second adjusting units 271, 272 when a high-voltage scan signal is transmitted to the scan line 21.
The common electrode line 23 has different voltages when a high-voltage scan signal is transmitted to the scan line and when a low-voltage scan signal is transmitted to the scan line, so the common electrode line 23 has a voltage variation ΔVcom when a scan signal transmitted to the scan line ranges from a high-voltage scan signal to a low-voltage scan signal. Because the voltage on the common electrode line is also subject to impedance effect and capacitance effect during transmission of the recovery voltage signal and the low voltage signal over the scan line in a similar way to the scan signal, a coupled voltage resulting from the voltage on the common electrode line and a pixel electrode may just compensate for a variation of a feedthrough voltage ΔVp, ΔVpd, so that variations of the feedthrough voltages ΔVp, ΔVpd, at different locations of the same scan line may be reduced, thereby reducing flicker of the liquid crystal display panel and improving comfortableness of a user when viewing.
The first adjusting units 271 are configured to transmit low voltage signals to a common electrode line 23 from the start terminal and the end terminal of the common electrode line 23, respectively, when a high-voltage scan signal is transmitted to a scan line 21. The second adjusting units 272 are configured to transmit recovery voltage signals to the common electrode line 23 from the start terminal and the end terminal of the common electrode line 23, respectively, when either a high-voltage scan signal or a low-voltage scan is transmitted to the scan line. So the adjusted voltage is formed on the common electrode line by the first and the second adjusting units 271, 272 when a high-voltage scan signal is transmitted to the scan line 21.
When the liquid crystal display panel is relatively large in size and correspondingly the scan line 21 is relatively long, the adjusting devices 27 may transmit the low voltage signals and the recovery voltage signals to the common electrode line 23 from both the start terminal and the end terminal of the common electrode line 23, thereby reducing a delay of signal transmission over the common electrode line 23 and further improving adjustment effect.
Referring to
The first transistor 48 is adapted to transmit a low voltage signal to the common electrode line 23 corresponding to the scan line 21. When a high-voltage scan signal is transmitted to a certain scan line 21, the high-voltage scan signal is transmitted to the gate electrode of the first transistor 48 through the scan line 21. Because the high scan voltage is higher than a threshold voltage of the first transistor 48, the first transistor 48 is turned on. The first transistor 48 transmits the low voltage signal to the common electrode line 23. When the low-voltage scan signal is transmitted to the scan line 21, the low-voltage scan signal is transmitted to the gate electrode of the first transistor 48 through the scan line 21. Because the low scan voltage is lower than the threshold voltage of the first transistor 48, the first transistor 48 is turned off.
The second transistor 49 is adapted to transmit a recovery voltage signal V1 to the common electrode line 23 corresponding to the scan line 21. Because the high scan voltage source Vgh has a voltage higher than a threshold voltage of the second transistor 49, the second transistor 49 is in an ON state all the time. The second transistor 49 transmits the recovery voltage signal V1 to the common electrode line 23 all along. So when a high-voltage scan signal is transmitted to a scan line 21, the first transistor and the second transistor are both turned on and form an adjusted voltage V2 on a common electrode line 23 corresponding to the scan line 21 (as shown in
The first transistor 48 and the second transistor 49 can also include a preset number of connected transistors. For instance, three transistors in an effective connection can function as a transistor, thus they are equivalent to a first transistor 48 or a second transistor 49.
The pixel voltage varies smoothly due to compensation of the coupled voltage resulting from the voltage on the common electrode line and the pixel electrode. As can be seen from
Furthermore, the invention provides an adjusting method of the above liquid crystal display panel. Referring to
At step S1101, a scan signal is transmitted in sequence to each scan line 21.
Each scan line 21 of the liquid crystal display panel is coupled with the scan driver, and each data line 22 is coupled with the data driver. The scan driver transmits the scan signal in sequence to each scan line 21, and the TFTs of the display units 13 on only one of the scan lines 21 are turned on at a certain time.
At step S 1102, an adjusted voltage is formed on a common electrode line 23 corresponding to a certain scan line 21 when a high-voltage scan signal is transmitted to the scan line.
When a high-voltage scan signal is transmitted through a certain scan line 21, the TFTs of the display units 13 on the scan line are turned on. The data driver transmits an image data signal to a corresponding display unit 13 via a data line 22. Each scan line 21 corresponds to a common electrode line 23. When the scan signal is transmitted to a certain scan line 21, an adjusted voltage V2 is formed on a common electrode line 23 corresponding to the scan line 21, thereby pulling down the voltage of the common electrode line 23.
At step S1103, a recovery voltage signal V1 is transmitted to the common electrode line 23 when a low-voltage scan signal is transmitted to the scan line.
The adjusted voltage V2 is above the low scan voltage Vg1 and below the recovery voltage V1.
At step S1104, a coupled voltage resulting from the voltage on the common electrode line and the pixel electrode on the scan line 21 positively compensates for a feedthrough voltage.
The liquid crystal display panel and the adjusting method thereof according to the invention have been described in detail as above, and principles and embodiments of the invention have been set forth by way of specific examples. The above description of the embodiments is merely for the purpose of facilitating understanding of the inventive method and the essential idea thereof. Those skilled in the art can make modifications to the embodiments and their application in light of the inventive idea. In summary, the disclosure of the descriptions shall not be taken as limiting the scope of the invention.
Number | Date | Country | Kind |
---|---|---|---|
200710128448.1 | Jul 2007 | CN | national |