CN101364378A - Electroluminescence display device and driving method thereof - Google Patents

Abstract

The invention discloses an electroluminescent display and a driving method thereof. The electroluminescent display comprises pixels, a gate driver, a source driver, a time schedule controller and a VDL voltage source. The pixels are arranged in a matrix mode with n rows and m columns, wherein the pixels in each row are linked by a gate line, and the pixels in each column are linked by a data line; the gate driver drives the gate line; the source driver drives the data line; the time schedule controller controls the gate driver and the source driver; and the VDL voltage source provides negative voltage signals; wherein a sequential control switch is arranged between the data line and the source driver and is connected with the output of the source driver or the VDL voltage source. The electroluminescent display and the driving method thereof improve the performance degradation of electroluminescent elements.

Description

Electroluminescent display and driving method thereof

Technical field

The present invention relates to a kind of display and driving method thereof, relate in particular to a kind of electroluminescent display and driving method thereof.

Background technology

Electroluminescent display is to utilize the brightness of electroluminescence (EL) element to change to come display image.In recent years, existing resistance active display is compared in the development of the development of EL element, especially organic electroluminescent LED (OLED), has more low energy consumption and more frivolous characteristics under same brightness.Therefore, electroluminescent display will be applied in the various big-and-middle undersized terminal presentation facilities more and more widely.

The display structure of active el display as shown in Figure 1, active el display has the pixel that the capable m of n is listed as into matrix distribution; Gate drivers 101 is used for gate line (G1, G2 ... Gn) drive gating; Source electrode driver 102 is used for data line (D1, D2 ... Dm) drive; Gate drivers 101 and source electrode driver 102 are driven by time schedule controller 103, and pixel cell is made up of the zone that intersects between gate line and the data line, and forms matrix distribution in active el display; In the zone of this intersection, there are two thin film transistor (TFT)s (TFT), when the residing gate line of TFT during by gating, the data-signal of data line charges into memory capacitance, and keeps this data-signal by memory capacitance; This data-signal will be controlled the on state current of the TFT that is connected with EL, and the brightness that this on state current will be controlled EL shows to realize GTG.

The active el display drive principle of prior art as shown in Figure 2.In conjunction with Fig. 1 and Fig. 2 its driving method is described as follows: 1) when the sweep signal that applies on the gate lines G 1 when VGL switches to VGH, the T that keeps at sweep signal VGH is in the time, the second thin film transistor (TFT) Q11-2 is by gating; The data-signal VD1 of data line D1 input gives memory capacitance C11 charging; Memory capacitance C11 keeps the on state current of data-signal VD1 control the first film transistor Q11-1; The demonstration of this pixel cell is finished in the brightness of the on state current decision light-emitting component D11 of the first film transistor Q11-1.Same, with light-emitting component D11 will be with the brightness of other EL of delegation according to gate lines G 1 data line D2 imports to the Dm during by gating data-signal determine respectively.2) after gate lines G 1 is stopped gating, gate lines G 2 is by gating; Same, the brightness of the pixel that gate lines G 2 is expert at will be according to gate lines G 2 during by gating data line D1 determine respectively to the data-signal that Dm goes up input.3) in a frame time of display image, gate lines G 1 to Gn is successively by gating, and each pixel cell is finished the demonstration to a frame picture.In electroluminescent display, two TFT of its pixel cell are nTFT usually, and the magnitude of voltage of sweep signal VGL is less than 0, and the magnitude of voltage of sweep signal VGH is greater than 0, and data-signal VDm is also greater than 0.Therefore, in electroluminescent display, only there is positive voltage to be applied to the TFT of control EL element electric current, easily cause the threshold voltage skew of TFT, thereby the luminance degradation and the life-span of causing electro-luminescence display device shortens; In addition, reservior capacitor only is filled with positive voltage and does not discharge, and also can cause performance degradation and shortens life-span of electro-luminescence display device.

Summary of the invention

Technical matters to be solved by this invention provides a kind of electroluminescent display and driving method thereof, to improve the electroluminescent cell performance degradation.

The present invention solves the problems of the technologies described above the technical scheme that adopts to provide a kind of electroluminescent display, comprising:

The capable m of n is listed as into the pixel of matrix distribution, and each row pixel is connected by a gate line, and each row pixel is connected by a data line, and m and n are natural number;

One gate drivers drives described gate line;

The one source pole driver drives described data line;

Time schedule controller is controlled described gate drivers and source electrode driver;

The VDL voltage source provides negative voltage signal;

Wherein, also comprise a sequential gauge tap between described data line and the source electrode driver, the output or the VDL voltage source of described sequential control switch and source electrode driver link to each other.

The present invention may further comprise the steps for solving the problems of the technologies described above the driving method that a kind of above-mentioned electroluminescent display also is provided:

Time schedule controller output is line frequency signal TP periodically;

Source electrode driver is at the negative edge outputting data signals of line frequency signal TP;

In period 1, described sequential control switch is connected to the VDL voltage source, imports negative voltage signal on the data line at data-signal;

In second round, described sequential control switch is connected to source electrode driver, input data signal on the data line at data-signal.

The present invention contrasts prior art following beneficial effect: electroluminescent display provided by the invention and driving method thereof, by between data line that has electroluminescent display now and source electrode driver, increasing a sequential control switch, this sequential control switch replaces the data-signal VDm of output source driver or the negative voltage signal of VDL voltage source under control signal SP drives, guarantee that memory capacitance alternately discharges and recharges, improve the electroluminescent cell performance degradation.

Description of drawings

Fig. 1 is the active el display structural representation of prior art.

Fig. 2 is that the active el display of prior art drives synoptic diagram.

Fig. 3 is the drive principle synoptic diagram of technical solution of the present invention.

Fig. 4 is the system architecture diagram of the embodiment of the invention.

Fig. 5 is the drive signal synoptic diagram of the embodiment of the invention.

Embodiment

The invention will be further described below in conjunction with drawings and Examples.

Fig. 3 is the drive principle synoptic diagram of technical solution of the present invention.

Please refer to Fig. 3, the drive principle of technical solution of the present invention: 1) when the sweep signal on the gate lines G 1 when VGL switches to VGH, the T that keeps at sweep signal VGH is in the time, the second thin film transistor (TFT) Q11-2 is by gating; T is divided into two time period T1 and T2; In time, data line D1 goes up input negative voltage signal VDL at T1, and memory capacitance C11 discharge and the first film transistor Q11-1 are in OFF state; In time, data line D1 goes up input data signal VD1 at T2, and memory capacitance C11 is recharged and keeps the on state current of data-signal VD1 control the first film transistor Q11-1; The demonstration of this pixel cell is finished in the brightness of the on state current decision light-emitting component D11 of the first film transistor Q11-1.Same, when gate lines G 1 gating, also will discharge in the time in other pixels at T1 with delegation with light-emitting component D11, T2 charges into the data-signal of required display brightness in the time.2) after gate lines G 1 is stopped gating, gate lines G 2 is by gating; Same, the pixel that gate lines G 2 is expert at also will be discharged in the time at T1, and T2 charges into the data-signal of required display brightness in the time.3) in a frame time of display image, gate lines G 1 successively by gating, repeats 1 to Gn successively) charge and discharge process, each pixel cell is finished the demonstration to a frame picture.

Fig. 4 is the system architecture diagram of the embodiment of the invention, and Fig. 5 is the drive signal synoptic diagram of the embodiment of the invention.

To specifically introduce the preferred embodiments of the present invention below, please refer to Fig. 4, and in conjunction with Fig. 1, data line (the D1 of the electroluminescent display of present embodiment, D2 ... Dm) increase a sequential control switch 402 and between the source electrode driver 401, this sequential control switch 402 is driven by control signal SP, the negative voltage signal of the data-signal of output source driver 401 or VDL voltage source.Please refer to Fig. 5, the driving process of present embodiment is as follows: when the frame picture began to show, its picture showed output line frequency signal TP; Source electrode driver 401 is exported corresponding data presented signal VDm when the control signal SP of sequential gauge tap 402 is low level at the negative edge of line frequency signal TP, data line is connected to the VDL voltage source, at this moment the data line output signal is VDL, and the VDL magnitude of voltage is less than 0, and memory capacitance is discharged; When the control signal SP of sequential gauge tap 402 was high level, data line was connected to the output of source electrode driver 401, and at this moment data line is output as the corresponding data-signal VDm that shows GTG, and Cmn charges to memory capacitance.

In sum, the present invention is at the data line (D1 of existing electroluminescent display, D2 ... Dm) increase a sequential control switch 402 and between the source electrode driver 401, this sequential control switch 402 replaces the data-signal VDm of output source driver or the negative voltage signal of VDL voltage source under control signal SP drives, guarantee memory capacitance (C11, C12 ... Cmn) alternately discharge and recharge, improve the electroluminescent cell performance degradation.

Though the present invention discloses as above with preferred embodiment; right its is not in order to qualification the present invention, any those skilled in the art, without departing from the spirit and scope of the present invention; when can doing a little modification and perfect, so protection scope of the present invention is when with being as the criterion that claims were defined.

Claims (2)

1, a kind of electroluminescent display comprises:

The capable m of n is listed as into the pixel of matrix distribution, and each row pixel is connected by a gate line, and each row pixel is connected by a data line, and m and n are natural number;

One gate drivers drives described gate line;

The one source pole driver drives described data line;

Time schedule controller is controlled described gate drivers and source electrode driver;

The VDL voltage source provides negative voltage signal;

It is characterized in that, also comprise a sequential gauge tap between described data line and the source electrode driver, the output or the VDL voltage source of described sequential control switch and source electrode driver link to each other.

2, a kind of driving method of electroluminescent display according to claim 1 may further comprise the steps:

Time schedule controller output is line frequency signal TP periodically;

Source electrode driver is at the negative edge outputting data signals of line frequency signal TP;

In period 1, described sequential control switch is connected to the VDL voltage source, imports negative voltage signal on the data line at data-signal;

In second round, described sequential control switch is connected to source electrode driver, input data signal on the data line at data-signal.