Display unit driving method and display system
Technical field
The present invention is last relevant for a kind of display drive method, particularly relevant for a kind of display driver circuit that is used for AC-Vcom.
Background technology
Fig. 1 shows traditional display unit 10 and a plurality of signal V
Gn, V
Sn, V
Com, V
CstAnd VD
nSequential chart.Display unit 10 comprises switch 14, pixel 12 and electric capacity 16, switch controlling signal V
GnCS 14 conducting or not conductings, when switch 14 conductings, source control signal Vsn and drain electrode control signal V
DnBe idiostatic, 16 of electric capacity are according to drain electrode control signal V
DnWith common voltage signal V
ComVoltage difference charging, pixel 12 is coupled in parallel with electric capacity 16, wherein a termination is received drain electrode control signal V
Dn, the other end receives common voltage signal V
Com, pixel 12 two ends have a voltage difference to exist in the time of so, and then this pixel 12 can video picture, wherein common voltage signal V
ComBe to exchange common voltage signal AC-V
Com
Learn switch 14 output drain electrode control signal V by Fig. 1
DnTo an end of electric capacity 16 and pixel 14, because capacitance coupling effect, before switch 14 conductings, the V of alternation
ComSignal will cause drain electrode control signal V
DnVoltage can be high especially or low especially, cause switch 16 to produce excessive leakage current or cause the switch damage.
Summary of the invention
The present invention provides a kind of display unit, and display unit comprises an electric capacity, a pixel and a switch.Electric capacity has two-end-point and receives drain electrode control signal (V respectively
Dn) and common voltage signal (V
Com), come charge or discharge according to drain electrode control signal and common voltage voltage of signals difference.Pixel has two-end-point and receives drain electrode control signal and common voltage signal respectively, and comes video picture according to drain electrode control signal and common voltage voltage of signals difference.Switch comprises first termination receipts source control signal (V
Sn), second termination receives switch controlling signal (V
Gn) and the 3rd end (V
Dn) couple pixel and electric capacity, wherein conducting makes source control signal be sent to pixel and electric capacity via the 3rd end to switch according to switch controlling signal.Wherein switch is according to switch controlling signal conducting twice in a frame (Frame), and conducting for the first time makes pixel image, and conducting for the second time makes capacitor discharge with the voltage level of avoiding switch the 3rd end V because of alternation
ComSignal and coupling effect and surpass a predetermined voltage.
The present invention more provides a kind of display unit driving method, and wherein display unit comprises a pixel, a switch and an electric capacity, and its method comprises: in a frame, according to switch controlling signal (V
Gn) actuating switch (for the first time conducting), make electric capacity charge to a specific potential according to drain electrode control signal and common voltage voltage of signals difference, off switch afterwards, pixel is come video picture according to the voltage difference at electric capacity two ends; And in frame,, and come discharge capacity with common voltage voltage of signals difference according to the drain electrode control signal again according to switch controlling signal actuating switch (for the second time conducting), with the voltage level of an end points of avoiding the switch coupling capacitance above a predetermined voltage.
The present invention more provides a kind of display system, and in order to show image, display system comprises gate drivers, source electrode driver and display device, and wherein display device comprises a plurality of display units, and each display unit comprises an electric capacity, a pixel and a switch respectively.Electric capacity has two-end-point and receives drain electrode control signal (V respectively
Dn) and common voltage signal (V
Com), come charge or discharge according to drain electrode control signal and common voltage voltage of signals difference.Pixel has two-end-point and receives drain electrode control signal and common voltage signal respectively, and comes video picture according to drain electrode control signal and common voltage voltage of signals difference.Switch comprises first termination receipts source control signal (V
Sn), second termination receives switch controlling signal (V
Gn) and the 3rd end couple pixel and electric capacity, wherein conducting makes source control signal be sent to pixel and electric capacity via the 3rd end to switch according to switch controlling signal.Wherein switch is according to switch controlling signal conducting twice in a frame (Frame), and conducting for the first time makes pixel image, and conducting for the second time makes capacitor discharge surpass a predetermined voltage with the voltage level of avoiding switch the 3rd end.
Description of drawings
For letting the present invention can be more obviously understandable, the hereinafter spy enumerates preferred embodiment, and conjunction with figs., elaborate as follows, wherein:
Fig. 1 is the sequential chart that shows traditional display unit and a plurality of signals.
Fig. 2 shows according to the display unit of first embodiment of the invention and the sequential chart of a plurality of signals.
Fig. 3 shows according to the display unit of second embodiment of the invention and the sequential chart of a plurality of signals.
Fig. 4 shows according to the display unit of third embodiment of the invention and the sequential chart of a plurality of signals.
Fig. 5 is the display system that shows according to fourth embodiment of the invention.
Fig. 6 is the sequential chart that shows according to gate drivers, display device and a plurality of switch controlling signals of fifth embodiment of the invention.
Embodiment
Fig. 2 is the display unit 20 and a plurality of signal V that shows according to first embodiment of the invention
Gn, V
Sn, V
Com, V
CstAnd V
DnSequential chart.Display unit 20 comprises switch 24, pixel 22 and electric capacity 26, and switch 24 can be that transistor constitutes, and switch 24 comprises first termination receipts source control signal V
Sn, second termination receives switch controlling signal V
GnCouple pixel 22 and electric capacity 26 with the 3rd end, wherein switch 24 is according to switch controlling signal V
GnConducting makes source control signal V
SnBe sent to pixel 22 and electric capacity 26 via the 3rd end, when switch 24 conductings, source control signal V
SnWith drain electrode control signal V
DnBe idiostatic.Electric capacity 26 has two-end-point and receives drain electrode control signal V respectively
DnWith common voltage signal V
Com, and according to drain electrode control signal V
DnWith common voltage signal V
ComVoltage difference V
Cst(capacitance voltage is poor) comes charge or discharge.Pixel 22 and electric capacity 26 coupled in parallel, pixel 22 have two-end-point and receive drain electrode control signal V respectively
DnWith common voltage signal V
Com, and according to drain electrode control signal V
DnWith common voltage signal V
ComVoltage difference come video picture, when there was a voltage difference at pixel 22 two ends, pixel 22 can video picture, wherein common voltage signal V
ComBe to exchange common voltage signal AC-V
ComThe display unit of Fig. 1 and Fig. 2 has identical circuit structure, so the present invention's drain electrode end that under the hardware configuration that need not change display unit, can solve switch 24 produces the problem of non-expection high pressure, avoids causing the phenomenon of switch damage or high leakage current.
The present invention utilizes switch controlling signal V
GnActuating switch is 24 twice in a frame (Frame); During switch 24 conductings for the first time; Pixel 22 video pictures and electric capacity 26 chargings (are drawn the square wave of point) during switch 24 conductings for the second time among the figure, electric capacity 26 is discharged to the accurate position of a low-voltage and surpasses a predetermined voltage with the voltage level of avoiding switch 24 the 3rd end; Because the 3rd end drops to the accurate position of low-voltage earlier, when next frame, the 3rd terminal voltage just can be because of the V of alternation
ComReach coupling effect and surpass a predetermined voltage, produce problems such as high leakage current to avoid switch 24.
Fig. 3 is the display unit 20 and a plurality of signal V that shows according to second embodiment of the invention
Gn, V
Sn, V
Com, V
CstAnd V
DnSequential chart.When second embodiment and the first embodiment difference are conducting for the second time, switch controlling signal V
GnVoltage quasi position lower, so electric capacity 26 velocities of discharge and voltage can be by switch controlling signal V
GnControl.
Fig. 4 is the display unit 20 and a plurality of signal V that shows according to third embodiment of the invention
Gn, V
Sn, V
Com, V
CstAnd V
DnSequential chart.The 3rd embodiment and the second embodiment difference are that the time point of switch conduction can adjust for the second time in frame (Frame).
Fig. 5 is the display system 50 that shows according to fourth embodiment of the invention, and display system 50 comprises control system 54, gate drivers 51, source electrode driver 53 and display device 52, and wherein display device 52 comprises a plurality of display units, for example: Fig. 2 display unit 20.
Fig. 6 is gate drivers 51, display device 52 and a plurality of switch controlling signal V that shows according to fifth embodiment of the invention
GnSequential chart.Gate drivers 51 can be controlled each switch controlling signal V
GnExport the time point of second end of switch 24 of each display unit 20 of display device 52 to.For example: frame Frame1 comprises driving period f
11With capacitor discharge period f
12, frame Frame2 comprises driving period f
21With capacitor discharge period f
22Switch controlling signal V
G1~V
Gn+3Driving period f
11, f
21In be orderly sent to each display unit, so each conducting in regular turn makes charging of corresponding electric capacity and respective pixel video picture to inductive switch.Switch controlling signal V
G1~V
Gn+3At capacitor discharge period f
12, f
22, can two one group or asymmetric group of number be orderly sent to each display unit, so each conducting in regular turn makes corresponding capacitor discharge to inductive switch.
Though the present invention discloses as above with preferred embodiment; Right its is not in order to limiting scope of the present invention, any those who familiarize themselves with the technology, do not breaking away from the spirit and scope of the present invention; When can doing a little change and retouching, so protection scope of the present invention is when looking being as the criterion that the claim scope defined.