THIN FILM TRANSISTOR-LIQUID CRYSTAL DISPLAY DEVICE AND ITS DRIVING METHOD
The invention discloses a TFT-LCD and its driving method, TFT-LCD comprises an array substrate and a color filter substrate, a common electrode on said color filter substrate being divided into multiple columns, each of which corresponding to one column of pixels; on color filter substrate, odd number columns are first common electrodes, even number columns are second common electrodes; difference between voltages input to said first common electrodes and said second common electrodes is larger than zero and less than dynamic range of driving voltage of liquid crystal driving voltage-transmittance curve. By setting two common electrode voltages, TFT-LCD and its driving method provided by the invention can make dynamic range of input voltage required for driving liquid crystal display device be smaller than dynamic range of driving voltage of liquid crystal driving voltage-transmittance curve, thus reducing power consumption during driving the liquid crystal.
The present invention relates to the field of liquid crystal display, and to a TFT (Thin Film Transistor) Liquid Crystal Display device and its driving method.
BACKGROUND OF THE INVENTIONLiquid crystals in a TFT-LCD (Liquid Crystal Display) are sandwiched by an array substrate on which there are a TFT and a pixel electrode, and a color filter substrate on which there are a color resin and a common electrode, wherein the liquid crystals inverse when a voltage is applied between the common electrode and the pixel electrode. For a LCD of normally white mode, the less the voltage difference between two sides of liquid crystals is, the larger the transmittance of the liquid crystal molecules are. When a voltage is applied between two sides of the liquid crystal molecules, the liquid crystal molecules rotate, thus making a light provided by a backlight transmitting out through the liquid crystal molecule, wherein the amount of the light transmitted out is determined by rotation angle of the liquid crystal molecules. Due to the property of the liquid crystal molecules itself, if driving with a voltage of only one polarity, the liquid crystal molecules is extremely vulnerable to aging, thus shortening the lifetime of the liquid crystal molecule. Therefore, in order to prevent it from aging, it is necessary to drive the liquid crystal molecules in such a way that voltages of positive polarity and negative polarity are alternately used for driving.
A structural schematic diagram of a TFT in the prior art is as shown in
After the pixel capacitor (CLc) 106 has been charged, a turn-off voltage is supplied to the gate 102 of the TFT through the gate line 101, the TFT being in an OFF state at this time, and the voltage already charged to the pixel capacitor (CLc) 106 can be maintained until next time the gate is turned on.
A schematic diagram of driving for liquid crystal molecules in the prior art is as shown in
Not only the picture flickering is avoided, but also the liquid crystal is prevented from aging, on the premise that the liquid crystal molecules continuously rotates by setting the common electrode voltage.
A schematic diagram of the TFT array on the array substrate in the prior art is as shown in
(1) Frame Inversion:
That is, the liquid crystal is driven with the voltages of same polarity in one frame of picture, and with reverse polarity of voltage in the next adjacent frame of the picture. A schematic diagram of polarities of voltages between two sides of respective pixel capacitors in TFT array of respective frames when driving liquid crystal to inverse by means of the frame inversion according to the prior art is as shown in
(2) Row Inversion
That is, in one frame of picture, the pixel capacitors on the same row of gate lines are driven with the voltages of same polarity, and the pixel capacitors on the adjacent row of gate lines are driven with the voltages of reverse polarity. A schematic diagram of polarities of voltages between two sides of respective pixel capacitors in TFT array of respective frames when driving liquid crystal to inverse by means of the row inversion according to the prior art is as shown in
(3) Column Inversion
That is, in one frame of picture, the pixel capacitors on the same column of gate lines are driven with the voltages of same polarity, and the pixel capacitors on the adjacent column of gate lines are driven with the voltages of reverse polarity. A schematic diagram of polarities of voltages between two sides of respective pixel capacitors in TFT array of respective frames when driving liquid crystal to inverse by means of the column inversion according to the prior art is as shown in
(4) Point Inversion
That is, the polarities of driving voltage of any adjacent pixel capacitors are different in one frame of picture, and each pixel capacitor is driven with reverse polarity of voltage in the next adjacent frame of the picture with respect to the previous adjacent frame of the picture. A schematic diagram of polarities of voltage between two sides of respective pixel capacitors in TFT array of respective frames when driving liquid crystal to inverse by means of the point inversion according to the prior art is as shown in
There are problems in driving manners for liquid crystal in the prior art, in that: since one common electrode voltage is employed, there is only one reference voltage when positive directional and negative directional driving for liquid crystal, so that dynamic range of driving voltage is large, as shown in
An embodiment of the present invention is to provide a liquid crystal display device, which can reduce power consumption in the course of driving the liquid crystal to inverse, with respect to the problems in the prior art.
An embodiment of the present invention provides a thin film transistor-liquid crystal display device, comprising an array substrate and a color filter substrate, a common electrode on said color filter substrate being divided into multiple columns, each of which corresponding to one column of pixels;
on said color filter substrate, odd number columns are first common electrodes, and even number columns are second common electrodes;
the difference between voltages input to said first common electrodes and said second common electrodes is larger than zero and less than a dynamic range of the driving voltage of a liquid crystal driving voltage-transmittance curve.
A driving method for the thin film transistor-liquid crystal display device may comprise:
during the thin film transistor-liquid crystal display device displaying a frame, a first common electrode voltage signal is input to said first common electrodes while second common electrode voltage signal is input to said second common electrodes; and a positive directional driving voltage signal of a first driving voltage-transmittance curve corresponding to said first common electrode voltage is input to odd number columns of data lines on said array substrate of said thin film transistor-liquid crystal display device, while a negative directional driving voltage signal of a second driving voltage-transmittance curve corresponding to said second common electrode voltage is input to even number columns of data lines on said array substrate of said thin film transistor-liquid crystal display device;
during the thin film transistor-liquid crystal display device displaying a next adjacent frame, said second common electrode voltage signal is input to said first common electrodes while said first common electrode voltage signal is input to said second common electrodes; and said negative directional driving voltage signal of said second driving voltage-transmittance curve corresponding to said second common electrode voltage is input to said odd number columns of data lines on said array substrate of said thin film transistor-liquid crystal display device, while said positive directional driving voltage signal of said first driving voltage-transmittance curve corresponding to said first common electrode voltage is input to said even number columns of data lines on said array substrate of said thin film transistor-liquid crystal display device;
the difference between voltages input to said first common electrodes and said second common electrodes is larger than zero and less than the dynamic range of the driving voltage of the liquid crystal driving voltage-transmittance curve.
An embodiment of the present invention also provides a thin film transistor-liquid crystal display device comprising an array substrate and a color filter substrate, a common electrode on said color filter substrate being divided into an array corresponding to pixels;
on said color filter substrate, first common electrodes are set in odd number pixels on odd number rows and even number pixels on even number rows;
second common electrodes are set in even number pixels on odd number rows and odd number pixels on even number rows;
the difference between voltages input to said first common electrodes and said second common electrodes is larger than zero and less than a dynamic range of the driving voltage of a liquid crystal driving voltage-transmittance curve.
A driving method for the thin film transistor-liquid crystal display device comprises:
during the thin film transistor-liquid crystal display device displaying a frame, first common electrode voltage signal is input to said first common electrodes while second common electrode voltage signal is input to said second common electrodes; and a positive directional driving voltage signal of a first driving voltage-transmittance curve corresponding to said first common electrode voltage is input to odd number columns of data lines for the odd number rows and even number columns of data lines for the even number rows on said array substrate of said thin film transistor-liquid crystal display device, while a negative directional driving voltage signal of a second driving voltage-transmittance curve corresponding to said second common electrode voltage is input to even number columns of data lines for the odd number rows and odd number columns of data lines for the even number rows on said array substrate of said thin film transistor-liquid crystal display device;
during the thin film transistor-liquid crystal display device displaying a next adjacent frame, said second common electrode voltage signal is input to said first common electrodes while said first common electrode voltage signal is input to said second common electrodes; and said negative directional driving voltage signal of said second driving voltage-transmittance curve corresponding to said second common electrode voltage is input to the odd number columns of data lines for the odd number rows and the even number columns of data lines for the even number rows on said array substrate of said thin film transistor-liquid crystal display device, while said positive driving voltage signal of said first driving voltage-transmittance curve corresponding to said first common electrode voltage is input to the even number columns of data lines for the odd number rows and the odd number columns of data lines for the even number rows on said array substrate of said thin film transistor-liquid crystal display device;
the difference between voltages input to said first common electrodes and said second common electrodes is larger than zero and less than the dynamic range of the driving voltage of the liquid crystal driving voltage-transmittance curve.
An embodiment of the present invention further provides a driving method for a thin film transistor-liquid crystal display device, comprising:
during the thin film transistor-liquid crystal display device displaying a frame, a first common electrode voltage signal is input to a common electrode on a color filter substrate of said thin film transistor-liquid crystal display device, and a positive directional driving voltage signal of a first driving voltage-transmittance curve corresponding to said first common electrode voltage is input to respective data lines on an array substrate of said thin film transistor-liquid crystal display device;
during the thin film transistor-liquid crystal display device displaying a next adjacent frame, second common electrode voltage signal is input to said common electrode on said color filter substrate of said thin film transistor-liquid crystal display device, and a negative directional driving voltage signal of a second driving voltage-transmittance curve corresponding to said second common electrode voltage is input to said respective data lines on said array substrate of said thin film transistor-liquid crystal display device;
the difference between voltages input to said first common electrodes and said second common electrodes is larger than zero and less than the dynamic range of the driving voltage of the liquid crystal driving voltage-transmittance curve.
The thin film transistor-liquid crystal display device and its driving method provided by the embodiments of the present invention set a first common electrode voltage and second common electrode voltage, and set the difference between the first and the second common electrode voltages to be larger than zero and less than dynamic range of the driving voltage of liquid crystal driving voltage-transmittance curve, thus it may be assured that the dynamic range of input voltage required for driving the liquid crystal display device is smaller than the dynamic range of the driving voltage of the liquid crystal driving voltage-transmittance curve, reducing the power consumption when driving the liquid crystal to inverse.
In the following, by way of accompanying drawings and embodiments, further detailed description will be made to the technical schemes of the embodiments of the present invention.
Liquid crystal display device uses lattice mode to display image of certain resolution. In the liquid crystal display device, one TFT, a pixel electrode and a common electrode set on a color filter substrate may constitute one display unit, which may be referred to as one pixel.
A structural schematic diagram of a color filter substrate in a first embodiment of TFT liquid crystal display device according to an embodiment of the present invention. Within the color filter substrate, the common electrode is divided into multiple columns, each corresponding to one column of pixels, the common electrode 11 of odd number columns being connected to a first transfer electrode point 13, the common electrode 12 of even number columns being connected to a second transfer electrode point 14. A Black Matrix (BM) 15 is also included in
A schematic diagram of a first embodiment of driving method of TFT liquid crystal display device according to an embodiment of the present invention is as shown in
As shown in
Wherein the difference between V1 and V2 should be larger than zero and less than dynamic range of the driving voltage of the first V-T curve, the beginning point and end point of which are respectively V1-1 and V1-2, and the beginning point and end point of dynamic range of the driving voltage of the second V-T curve are respectively V2-1 and V2-2. Generally, because parasitic capacitance exists among gate, source and drains of TFT, the ranges of positive directional and negative directional driving voltage in V-T curve are not completely identical.
During the liquid crystal display device displaying a frame, on the color filter substrate, the first common electrode voltage signal is input to the first common electrodes for the odd number columns of pixels; on the array substrate, the positive directional driving voltage signal of the first V-T curve, i.e. the voltage signals within the range from V1 to V1-2 of the first V-T curve as shown in
During the liquid crystal display device displaying a next adjacent frame, on the color filter substrate, the second common electrode voltage signal is input to the first common electrodes for the odd number columns of pixels, while on the array substrate, negative directional driving voltage signal of the second V-T curve is input to the odd number columns of data lines. Meanwhile, the first common electrode voltage signal is input to the second common electrodes for the even number columns of pixels, while on the array substrate, the positive directional driving voltage signal of the first V-T curve is input to the even number columns of data lines.
The column inversion as shown in
In
A structural schematic diagram of a color filter substrate in a second embodiment of TFT liquid crystal display device according to an embodiment of the present invention is as shown in
During the liquid crystal display device displaying a frame, the first common electrode voltage signal is input to the first transfer electrode point, i.e., to all of the first common electrodes, while the second common electrode voltage signal is input to the second transfer electrode point, i.e. to all of the second common electrodes. Also, the positive directional driving voltage signal of the first V-T curve corresponding to the first common electrode voltage is input to the odd number columns of data lines for the odd number rows and the even number columns of data lines for the even number rows on the array substrate of the liquid crystal display device, while the negative directional driving voltage signal of the second V-T curve corresponding to the second common electrode voltage is input to the even number columns of data lines for the odd number rows and the odd number columns of data lines for the even number rows on the array substrate of the liquid crystal display device.
During the liquid crystal display device displaying the next adjacent frame, the second common electrode voltage signal is input to the first transfer electrode point, i.e., to all of the first common electrodes, while the first common electrode voltage signal is input to the second transfer electrode point, i.e., to all of the second common electrodes. Also, the negative directional driving voltage signal of the second V-T curve corresponding to the second common electrode voltage is input to the odd number columns of data lines for the odd number rows and the even number columns of data lines for the even number rows on the array substrate of the liquid crystal display device, while the positive directional driving voltage signal of the first V-T curve corresponding to the first common electrode voltage is input to the even number columns of data lines for the odd number rows and the odd number columns of data lines for the even number rows on the array substrate of the liquid crystal display device.
With the structure of the color filter substrate as shown in
In the prior art, a common electrode is usually a layer of ITO (Indium-tin oxide) deposited on a color filter substrate, that is to say, the common electrodes are integration as a whole. With respect to the liquid crystal display device of such structure, the way of performing driving by setting two common electrodes can be that:
During the liquid crystal display device displaying a frame, the first common electrode voltage signal is input to the common electrode on the color filter substrate, and the positive directional driving voltage signal of the first V-T curve corresponding to the first common electrodes is input to respective data lines on the array substrate;
During the liquid crystal display device displaying the next adjacent frame, the second common electrode voltage signal is input to the common electrode on the color filter substrate, and the negative directional driving voltage signal of the second V-T curve corresponding to the second common electrodes is input to respective data lines on the array substrate.
The frame inversion can be achieved by means of such driving manner. Setting the difference between the first and the second common electrode voltages to be larger than zero and less than the dynamic range of the driving voltage of the first V-T curve can assure that the dynamic range of input voltage required for driving the liquid crystal display device in the prior art is smaller than the dynamic range of the driving voltage of the first V-T curve, thus reducing the power consumption when driving the liquid crystal display device.
Finally, it should be noted that the above embodiments is only for explaining the technical solutions of the embodiments of the present invention, and not for limiting. Although the embodiments of the present invention have been described in details with reference to the embodiments, those skilled in the art should be appreciated that the technical solutions of the present invention still can be modified or equivalently replaced; and these modifications or equivalent replacements will not make the modified technical solution departing from the spirit and scope of the technical solution of the present invention.
Claims
1. A thin film transistor-liquid crystal display device comprising an array substrate and a color filter substrate, wherein common electrodes on said color filter substrate form an array corresponding to pixels;
- on said color filter substrate, each of the common electrodes in an intersection of an odd number column and an odd number row of the array and each of the common electrodes in an intersection of an even number column and an even number row of the array are set as first common electrodes;
- each of the common electrodes in an intersection of the odd number column and the even number row of the array and each of the common electrodes in an intersection of the even number column and the odd number row of the array are set as second common electrodes;
- absolute difference between voltages input to said first common electrodes and said second common electrodes is larger than zero and less than a dynamic range of a driving voltage of a liquid crystal driving voltage-transmittance curve.
2. A driving method for the thin film transistor-liquid crystal display device according to claim 1, wherein the driving method comprises:
- during the thin film transistor-liquid crystal display device displaying a frame, first common electrode voltage signal is input to said first common electrodes while second common electrode voltage signal is input to said second common electrodes; and a positive directional driving voltage signal of a first driving voltage-transmittance curve corresponding to said first common electrode voltage is input to odd number columns of data lines for the odd number rows and even number columns of data lines for the even number rows on said array substrate of said thin film transistor-liquid crystal display device, while a negative directional driving voltage signal of a second driving voltage-transmittance curve corresponding to said second common electrode voltage is input to even number columns of data lines for the odd number rows and odd number columns of data lines for the even number rows on said array substrate of said thin film transistor-liquid crystal display device;
- during the thin film transistor-liquid crystal display device displaying a next adjacent frame, said second common electrode voltage signal is input to said first common electrodes while said first common electrode voltage signal is input to said second common electrodes; and said negative directional driving voltage signal of said second driving voltage-transmittance curve corresponding to said second common electrode voltage is input to the odd number columns of data lines for the odd number rows and the even number columns of data lines for the even number rows on said array substrate of said thin film transistor-liquid crystal display device, while said positive directional driving voltage signal of said first driving voltage-transmittance curve corresponding to said first common electrode voltage is input to the even number columns of data lines for the odd number rows and the odd number columns of data lines for the even number rows on said array substrate of said thin film transistor-liquid crystal display device.