The present application claims benefit of Chinese patent application CN 201410667208.9, entitled “Liquid Crystal Display Panel and Driving Method Thereof” and filed on Nov. 20, 2014, which is incorporated herein by reference.
The present disclosure relates to the technical field of liquid crystal display, and particularly to a liquid crystal display panel and a method for driving the liquid crystal display panel.
In order to satisfy people's requirements of high speed, high performance, as well as light and thin on electronic products, all kinds of electronic components are developing towards miniaturization. A variety of portable electronic devices have become the mainstream gradually. The liquid crystal display panels, which have many desirable characteristics, such as zero-radiation, are widely used currently as the image display panels for portable electronic devices.
In general, the liquid crystal display panel comprises scanning lines and data lines, wherein the data lines are driven by a source driver, and the scanning lines are driven by a gate driver. In the traditional large sized liquid crystal display panel, since the signal lines from the source driver to the left end or the right end of the liquid crystal display panel are longer than the signal lines from the source driver to the middle part of the panel, the resistances of the Wire on Arrays (WOAs) of the data lines in the fanout region of the panel would be different from one another to a large extent. The resistance difference would result in a poor display effect of the panel, and thus the display quality would be affected.
However, with
One of the technical problems to be solved by the present disclosure is to provide a liquid crystal display panel which can ease or eliminate the color shift phenomena. In addition, the present disclosure further provides a method for driving the liquid crystal display panel.
1) In order to solve the aforesaid technical problem, the embodiment of the present disclosure first provides a liquid crystal display panel, comprising: a source driver, used for providing a data signal; a gate driver, used for providing a gate signal according to a chamfering voltage; a pixel array, electrically connected between said source driver and said gate driver, and used for displaying an image according to said data signal and said gate signal; a chamfering circuit, electrically connected with said gate driver, and used for providing said chamfering voltage, wherein said chamfering circuit is configured to reduce a direct voltage received therein to a value of the chamfering voltage within a set time, so as to avoid a flicker of the image and maintain a uniformity of said liquid crystal display panel in each region thereof.
2) In one preferred embodiment of item 1) of the present disclosure, said chamfering circuit comprises: a direct voltage input end; a chamfering voltage output end; a first switching circuit, which is connected between said direct voltage input end and said chamfering voltage output end, and can be selectively turned on under a control of a first time sequence signal to selectively transmit a direct voltage received by said direct voltage input end to said chamfering voltage output end; a second switching circuit, which can be selectively turned on under a control of a second time sequence signal, said second time sequence signal and said first time sequence signal being pulse voltage signals with opposite polarities; a discharge circuit, which is connected between said second switching circuit and said chamfering voltage output end, and can be used for reducing a direct voltage transmitted to said chamfering voltage output end according to a set discharge slope to form said chamfering voltage when said second switching circuit is turned on, and wherein said discharge circuit comprises a discharge resistor, and a discharge rate of said discharge resistor is configured so that it can enable the direct voltage received by said direct voltage input end to be reduced to the value of the chamfering voltage within a time period less than or equal to a quarter of a sub pixel charge cycle.
3) In one preferred embodiment of item 1) or item 2) of the present disclosure, a value of said discharge resistor is no more than 500Ω.
4) In one preferred embodiment of any one of item 1) to item 3) of the present disclosure, said discharge circuit further comprises a diode, a cathode thereof being connected with said discharge resistor, and an anode thereof being connected with said second switching circuit.
5) In one preferred embodiment of any one of item 1) to item 4) of the present disclosure, wherein said first switching circuit comprises a first switching transistor, a second switching transistor, a first resistor, and a second resistor; wherein a first end of said second switching transistor is connected with said direct voltage input end, and a second end of said second switching transistor is connected with said chamfering voltage output end; wherein said first resistor and said second resistor are in series connection between said direct voltage input end and a first end of said first switching transistor; wherein a control end of said second switching transistor is connected between said first resistor and said second resistor; wherein a control end of said first switching transistor is used for receiving said first time sequence signal, and a second end of said first switching transistor is connected with the ground; and wherein said first switching transistor is N-type thin film transistor or N-type field effect transistor, and said second switching transistor is P-type thin film transistor or P-type field effect transistor.
6) In one preferred embodiment of any one of item 1) to item 5) of the present disclosure, wherein said second switching circuit comprises a third switching transistor, a first end of said third switching transistor being connected with an end of said discharge circuit, a second end of said third switching transistor being connected with the ground, and a control end of said third switching transistor receiving said second time sequence signal; and wherein said third switching transistor is N-type thin film transistor or N-type field effect transistor.
7) In one preferred embodiment of any one of item 1) to item 6) of the present disclosure, the value of the chamfering voltage generated by said discharge circuit is set to enable a flicker rate of said liquid crystal display panel to be less than or equal to a threshold, so as to maintain a uniformity of said liquid crystal display panel in each region thereof.
8) According to another aspect of the present disclosure, the present disclosure further provides a method for driving a liquid crystal display panel, comprising: during each charge cycle, inputting a direct voltage to a direct voltage input end of a chamfering circuit; inputting a first time sequence signal to a first switching circuit of said chamfering circuit to turn on said first switching circuit, and transmitting the direct voltage received by said direct voltage input end to a chamfering voltage output end; inputting a second time sequence signal to a second switching circuit of said chamfering circuit to turn on said second switching circuit, said second time sequence signal and said first time sequence signal being pulse voltage signals with opposite polarities; reducing, by a discharge circuit of the chamfering circuit, when said second switching circuit is turned on, a direct voltage transmitted to said chamfering voltage output end according to a set discharge slope to form a chamfering voltage, wherein a discharge resistor in said discharge circuit is arranged in such a manner that a discharge rate of said discharge resistor can enable the direct voltage received by said direct voltage input end to be reduced to the value of the chamfering voltage within a time period less than or equal to a quarter of a sub pixel charge cycle.
9) In one preferred embodiment of item 1) of the present disclosure, the value of the chamfering voltage generated by said discharge circuit is configured to enable a flicker rate of said liquid crystal display panel to be less than or equal to a threshold, so as to maintain a uniformity of said liquid crystal display panel in each region.
Compared with the prior art, one embodiment or a plurality of embodiments of the present disclosure may have the following advantages or beneficial effects.
According to the embodiments of the present disclosure, with the close-point voltage VGH(off) at the end of the saturation state of the gate being unchanged, the value of the discharge resistor in the chamfering circuit is reduced, and the duty ratio of the input pulse of the chamfering circuit is regulated so as to reduce the discharge time thereof. By means of which, the discharge rate of the chamfering circuit can be improved, and the charge capacity of the sub pixel can be increased. In this manner, the pixels located at the left end and the right end of the display panel can be charged to reach or close to the target voltage within the effective charge time, so that a flicker of the image can be avoided and the uniformity of the liquid crystal display panel in each region thereof can be improved. Therefore, the display effect at the middle part of the display panel is consistent with the display effect at the left end and the right end of the display panel, and thus the color shift issue of the liquid crystal display panel with Tri-Gate driving structure can be eliminated.
Other features and advantages of the present disclosure will be further explained in the following description, and partially become self-evident therefrom, or be understood through the embodiments of the present disclosure. The objectives and advantages of the present disclosure will be achieved through the structure and/or procedure specifically pointed out in the description, claims, and the accompanying drawings.
The accompanying drawings are used for providing further understandings of the present disclosure or the prior art and constitute one part of the description. The drawings, which illustrate the embodiments of the present disclosure, are used for interpreting the present disclosure together with the embodiments, not for limiting the technical solution of the present disclosure.
The present disclosure will be illustrated in detail hereinafter in combination with the accompanying drawings to make the purpose, technical solutions, and advantages of the present disclosure more clear.
Reference can be made to
As shown in
In a word, in the current driving method through which a low gray-scale mixed color image is displayed, for example, the yellow image with 128 gray-scales is displayed, the color shift phenomena would occur, i.e., the display area at the left end or the right end of the liquid crystal display panel would contain more red color ingredient relative to green color ingredient, or more green color ingredient relative to red color ingredient.
It should be noted that, after a display panel is produced, the effective charge time T1 of a sub pixel would not change. In order to improve the charge capacity of the sub pixel, and enable the voltage of the sub pixel to reach or close to a target voltage within a fixed effective charge time, the following embodiment is proposed by the applicant of the present application.
According to the embodiment of the present disclosure, with the close-point voltage VGH(off) at the end of the saturation state of the gate being unchanged, the value of the discharge resistor in the chamfering circuit is reduced, and the starting time and the duty ratio of the input pulse GVON of the chamfering circuit are regulated. By means of which, the discharge rate of the chamfering circuit can be improved, and the charge capacity of the sub pixel can be increased. In this manner, the pixels located at the left end and the right end of the display panel can be charged to reach or close to the target voltage within the effective charge time, so that a flicker of the image can be avoided and the uniformity of the liquid crystal display panel in each region thereof can be improved. Therefore, the display effect at the middle part of the display panel is consistent with the display effect at the left end and the right end of the display panel, and thus the color shift issue of the liquid crystal display panel with Tri-Gate driving structure can be eliminated.
The embodiment of the present disclosure will be illustrated hereinafter.
The second switching circuit 1203 is connected with the discharge circuit 1205, and is selectively turned on under a control of a second time sequence signal GVON.
The discharge circuit 1205, which is connected between said second switching circuit 1203 and said chamfering voltage output end VGH, is used for reducing a direct voltage transmitted to said chamfering voltage output end VGH according to a set discharge slope to form the chamfering voltage when the second switching circuit 1203 is turned on.
Specifically, the first switching circuit 1201 comprises a switching transistor A, a switching transistor Q1, a resistor R1, and a resistor R2, wherein a first end 1-S of the switching transistor Q1 is connected with the direct voltage input end VGHP, and a second end 1-D of the switching transistor Q1 is connected with the chamfering voltage output end VGH; the resistor R1 and the resistor R2 are in series connection between the direct voltage input end VGHP and a first end A-D of the switching transistor A; a control end 1-G of the switching transistor Q1 is connected between the resistor R1 and the resistor R2; and a control end A-G of the switching transistor A is used for receiving the first time sequence signal GVOFF, and a second end A-S of the switching transistor A is connected with the ground.
According to the present embodiment, the switching transistor Q1 is P-type thin film transistor or P-type field effect transistor, and the first end 1-S, the second end 1-D, and the control end 1-G thereof are a source, a drain, and a gate of the P-type transistor respectively. The switching transistor A is N-type thin film transistor or N-type field effect transistor, and the first end A-D, the second end A-S, and the control end A-G thereof are a drain, a source, and a gate of the N-type transistor respectively.
The second switching circuit 1203 comprises a switching transistor B, a first end B-D of the switching transistor B being connected with an end of the discharge circuit 1205, a second end B-S of the switching transistor B being connected with the ground, and a control end B-G of the switching transistor B receiving the second time sequence signal GVON. According to the present embodiment, the switching transistor B is N-type thin film transistor or N-type field effect transistor, and the first end B-D, the second end B-S, and the control end B-G thereof are a drain, a source, and a gate of the N-type transistor respectively.
It should be noted that, the first time sequence signal GVOFF and the second time sequence signal GVON are both voltage signals but with opposite polarities, which can be generated by a time sequence controller and an inverter. Specifically, the first time sequence signal GVOFF is generated by the time sequence controller, and then inverted into the second time sequence signal GVON by the inverter. The first time sequence signal GVOFF and the second time sequence signal GVON can be generated through other methods in addition to the above method.
Reference can be made to
It could be understood that, in addition to the P-type and N-type switching transistors of the embodiment of the present disclosure, other simple components which can play the role of switching can also be used in the circuit of other embodiments, such as triode, thyristor, and relay.
In addition, the discharge circuit 1205 may further comprise a Zener diode ZD1 to regulate the voltage thereof. An anode of the Zener diode ZD 1 is connected with the first end B-D of the switching transistor B, and a cathode of the Zener diode ZD1 is connected with the discharge resistor R3. The capacitor C as shown in
It should be noted that, the circuit structure of the above chamfering circuit 120 is just an example. The first switching circuit and the second switching circuit can be commutated through a commutation circuit, whereby the function of the chamfering circuit can be realized. Therefore, all other kinds of chamfering circuits, through which the direct voltage received therein can be reduced to the value of the chamfering voltage within a set time, so that the color shift phenomena can be eliminated, fall within the scope of the present disclosure.
As shown in
As shown in
When the first time sequence signal GVOFF is in a high-level state, the switching transistors A and Q1 are both turned on. At this moment, the second time sequence signal GVON is in a low-level state, the switching transistor B is turned off, and the voltage output by the chamfering voltage output end VGH is consistent with the voltage of the direct voltage input end VGHP. When the second time sequence signal GVON is in a high-level state, the switching transistor B is turned on, the first time sequence signal GVOFF is in a low-level state, and the switching transistors A and Q1 are both turned off. At this moment, the chamfering voltage is formed by the discharge resistor R3 and output to the chamfering voltage output end VGH. The chamfering voltage can also be generated through controlling the corresponding relationship between the first time sequence signal GVOFF and the second time sequence signal GVON, without the discharge resistor R3 being provided therein.
It should be noted that, in the present embodiment, the value of the discharge resistor R3 is preferably less than or equal to 500Ω. In one example, the value of the discharge resistor R3 is 3360. Since the value of the discharge resistor R3 is far less than the value of the discharge resistor used in the prior art, which is more than 1.5 KΩ in general, the discharge rate of the chamfering circuit can be increased to a large extent. By means of which, the voltage can be reduced to the preset chamfering voltage within a time period of 20 percent of the charge cycle.
As shown in
The result as shown in
In addition, the chamfering voltage (i.e., the gate off-state voltage) is preferably configured to enable a flicker rate of the liquid crystal display panel to be less than or equal to a threshold, and to maintain a uniformity of said liquid crystal display panel in each region thereof, wherein the flicker rate can be expressed as “(the highest brightness-the lowest brightness)/the average brightness”. Taking the liquid crystal display panel with 32 tri-gate as an example, the threshold of the flicker rate is 5, and the uniformity of the panel is higher than 80 percent.
In the present embodiment, the VGH(off) is preferably selected to be 20V, so that the flicker of the image due to the over-high VGH(off), or undesirable colors or noise due to the over-low VGH(off) when the thin film transistor of the panel is turned off can be avoided.
The preferred embodiments of the present disclosure are stated hereinabove, but the protection scope of the present disclosure is not limited by this. Any changes or substitutes readily conceivable for any one skilled in the art within the technical scope disclosed by the present disclosure shall be covered by the protection scope of the present disclosure.
Number | Date | Country | Kind |
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201410667208 | Nov 2014 | CN | national |
Filing Document | Filing Date | Country | Kind |
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PCT/CN2014/095574 | 12/30/2014 | WO | 00 |