CN105590579A

CN105590579A - Pixel driving circuit

Info

Publication number: CN105590579A
Application number: CN201410561282.2A
Authority: CN
Inventors: 张学一
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-10-21
Filing date: 2014-10-21
Publication date: 2016-05-18

Abstract

The invention relates to a pixel driving circuit. The pixel driving circuit includes a constant current source, a first scanning signal, a second scanning signal, a power source wire, a ground wire, a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a first capacitor, a second capacitor and an organic light emitting diode. The pixel driving circuit of the invention is simple in structure, based on the control of the first scanning signal on the fifth transistor and the capacitors, the influence of threshold voltage for driving the transistors on the driving current of the organic light-emitting diode can be eliminated, so that the light emission of the organic light-emitting diode is stable, and therefore, the quality of a display device can be improved; and the structure of the pixel driving circuit is simple, based on the collaborative effect of the transistors and the capacitors, the reliability of the pixel driving circuit can be improved.

Description

A kind of pixel-driving circuit

Technical field

The present invention relates to Display Technique field, relate in particular to a kind of current mode pixel-driving circuit of Organic Light Emitting Diode.

Background technology

In display floater; for effectively controlling the light emitting diode in pixel; conventionally can configure an image element circuit; but; adopt the display floater of image element circuit can face problems; such as transistor variation, voltage drop (IRdrop), light emitting diode are aging etc., and the problems referred to above will cause display floater brightness disproportionation, and the image quality of display floater is declined.

Organic Light Emitting Diode (OrganicLight-EmittingDiode, OLED) is current drives active illuminant device, has self-luminous, quick response, wide visual angle and can be produced on the first-class unique features of flexible substrate. Organic light emitting diode device, according to its type of drive difference, can be divided into passive drive and active driving; According to drive pattern difference, can be divided into voltage and drive and current drives. Voltage drives and refers to that the input signal of image element circuit is voltage signal, and in voltage-type pixel-driving circuit, a very little voltage change, by the variation that causes that output current is very large, therefore regulates more difficult to the accuracy of gray scale. Current drives refers to the type of drive of image element circuit using electric current as input signal, and output and input are linear relationships, more convenient to the adjusting of electric current, easily realizes the uniformity of brightness and the accuracy of display gray scale and regulates.

Consulting Fig. 1, is traditional 2T1C image element circuit schematic diagram, comprising: data wire, scan line, power line Vdd, the first transistor T10, transistor seconds T20, the first capacitor C 10, Organic Light Emitting Diode OLED10. Described the first transistor T10 comprises first grid g10, the first source electrode s10, the first drain electrode d10; Described transistor seconds T20 comprises second grid g20, the second source electrode s20, the second drain electrode d20; Described first grid g10 is electrically connected at scan line, described the first source electrode s10 is electrically connected at data wire, described the first drain electrode d10 is electrically connected at the top crown of second grid g20 and the first capacitor C 10, described the second source electrode s20 is electrically connected at power line Vdd, described the second drain electrode d20 is electrically connected at the anode of Organic Light Emitting Diode OLED20, the minus earth GND of described Organic Light Emitting Diode OLED10, the bottom crown ground connection GND of described the first capacitor C 10. But, in traditional 2T1C image element circuit, due to the variation of thin film transistor (TFT) threshold voltage, cause the electric current that flows through Organic Light Emitting Diode there are differences, have a strong impact on display quality.

Summary of the invention

For the problems referred to above, the invention provides a kind of pixel-driving circuit, simple in structure, can effectively solve the even problem of current unevenness that flows through Organic Light Emitting Diode, thereby promote the display effect of display unit.

For realizing above-mentioned purpose of the present invention, the invention provides a kind of pixel-driving circuit, concrete is a kind of current mode pixel-driving circuit of Organic Light Emitting Diode, comprising: constant-current source signal I1, the first sweep signal V1, the second sweep signal Vs, power line Vdd, ground wire GND, the first transistor T1, transistor seconds T2, the 3rd transistor T 3, the 4th transistor T 4, the 5th transistor T 5, the first capacitor C 1, the second capacitor C 2, Organic Light Emitting Diode OLED, described the first transistor T1 comprises first grid g1, the first source electrode s1, the first drain electrode d1, described transistor seconds T2 comprises second grid g2, the second source electrode s2, the second drain electrode d2, described the 3rd transistor T 3 comprises the 3rd grid g3, the 3rd source electrode s3, the 3rd drain electrode d3, described the 4th transistor T 4 comprises the 4th grid g4, the 4th source electrode s4, the 4th drain electrode d4, and described the 5th transistor T 5 comprises the 5th grid g5, the 5th source electrode s5, the 5th drain electrode d5, described the first source electrode s1 is electrically connected at constant-current source signal I1, described second grid g2 is electrically connected at first grid g1, and the second sweep signal Vs, described the first drain electrode d1 is electrically connected at the 4th grid g1, the 3rd grid g3, and one end of the first capacitor C 1, described the second source electrode s2 is electrically connected at constant-current source signal I1, described the second drain electrode d2 is electrically connected at the 4th drain electrode d4, the 3rd source electrode s3, described the 3rd drain electrode d3 is electrically connected at the anode of Organic Light Emitting Diode OLED, one end of the second capacitor C 2, described the 4th source electrode s4 is electrically connected at the other end of the first capacitor C 1, the 5th source electrode s5, and power line Vdd, the minus earth GND of described Organic Light Emitting Diode OLED, described the 3rd grid g3 is electrically connected at the first sweep signal V1, described the 5th drain electrode d5 is electrically connected at the other end of the second capacitor C 2.

Described power line Vdd is used for inputting power supply.

Described the 3rd transistor T 3 is driving tube; Described the first transistor T1, transistor seconds T2, the 4th transistor T 4 and the 5th transistor T 5 are switching tube.

Described the first transistor T1, transistor seconds T2, the 3rd transistor T 3, the 4th transistor T 4 and the 5th transistor T 5 are thin film transistor (TFT).

Compared with prior art beneficial effect of the present invention.

A kind of pixel-driving circuit provided by the invention, control by the first sweep signal to the 5th transistor and electric capacity, the impact of the threshold voltage of elimination driving transistors on Organic Light Emitting Diode drive current, make Organic Light Emitting Diode stable luminescence, and then improved the quality of display unit, extend the service life of display unit; And pixel-driving circuit of the present invention is simple in structure, by the synergy of transistor AND gate electric capacity, improve the reliability of pixel-driving circuit.

Brief description of the drawings

Fig. 1 is traditional 2T1C image element circuit schematic diagram.

Fig. 2 is the circuit diagram of pixel-driving circuit of the present invention.

Detailed description of the invention

Below in conjunction with the drawings and specific embodiments, the invention will be further elaborated.

Referring to Fig. 2, is the circuit diagram of pixel-driving circuit of the present invention. comprise: constant-current source signal I1, the first sweep signal V1, the second sweep signal Vs, power line Vdd, ground wire GND, the first transistor T1, transistor seconds T2, the 3rd transistor T 3, the 4th transistor T 4, the 5th transistor T 5, the first capacitor C 1, the second capacitor C 2, Organic Light Emitting Diode OLED, described the first transistor T1 comprises first grid g1, the first source electrode s1, the first drain electrode d1, described transistor seconds T2 comprises second grid g2, the second source electrode s2, the second drain electrode d2, described the 3rd transistor T 3 comprises the 3rd grid g3, the 3rd source electrode s3, the 3rd drain electrode d3, described the 4th transistor T 4 comprises the 4th grid g4, the 4th source electrode s4, the 4th drain electrode d4, and described the 5th transistor T 5 comprises the 5th grid g5, the 5th source electrode s5, the 5th drain electrode d5, described the first source electrode s1 is electrically connected at constant-current source signal I1, described second grid g2 is electrically connected at first grid g1, and the second sweep signal Vs, described the first drain electrode d1 is electrically connected at the 4th grid g1, the 3rd grid g3, and one end of the first capacitor C 1, described the second source electrode s2 is electrically connected at constant-current source signal I1, described the second drain electrode d2 is electrically connected at the 4th drain electrode d4, the 3rd source electrode s3, described the 3rd drain electrode d3 is electrically connected at the anode of Organic Light Emitting Diode OLED, one end of the second capacitor C 2, described the 4th source electrode s4 is electrically connected at the other end of the first capacitor C 1, the 5th source electrode s5, and power line Vdd, the minus earth GND of described Organic Light Emitting Diode OLED, described the 3rd grid g3 is electrically connected at the first sweep signal V1, described the 5th drain electrode d5 is electrically connected at the other end of the second capacitor C 2.

Described power line Vdd is used for inputting power supply.

Described the 3rd transistor T 3 is driving tube, drives the brightness of Organic Light Emitting Diode OLED to show; Described the first transistor T1, transistor seconds T2, the 4th transistor T 4 and the 5th transistor T 5 are switching tube. Whether gating of described the first transistor T1 and transistor seconds T2 control circuit, the 4th transistor T 4 plays the effect that is equivalent to a diode, prevents the reverse circulation of electric current.

Pixel-driving circuit operation principle of the present invention is: (1), the first sweep signal V1 are that high level, the second sweep signal Vs are while being high level, the first transistor T1 and transistor seconds T2 all open, the first capacitor C 1 enters charged state, the 5th transistor T 5 is opened, the second capacitor C 2 enters charged state, the 3rd transistor T 3 is opened, and data current flows through Organic Light Emitting Diode OLED, makes Organic Light Emitting Diode OLED luminous. (2), the first sweep signal V1 is low level, when the second sweep signal Vs is low level, the first transistor T1 and transistor seconds T2 all close, the first capacitor C 1 enters discharge condition, the 5th transistor T 5 is closed, the second capacitor C 2 enters discharge condition, the 4th transistor T 4 is opened, electric current is from power line Vdd flow through the 4th transistor T 4 and the 3rd transistor T 3, flow to Organic Light Emitting Diode OLED, Organic Light Emitting Diode OLED brightness preservation is constant, the impact of the threshold voltage of having eliminated the 3rd transistor T 3 on Organic Light Emitting Diode OLED drive current, solve the even problem of current unevenness that flows through Organic Light Emitting Diode OLED.

In sum, the invention provides a kind of pixel-driving circuit, control by the first sweep signal to the 5th transistor and electric capacity, the impact of the threshold voltage of elimination driving transistors on Organic Light Emitting Diode drive current, make Organic Light Emitting Diode stable luminescence, and then improved the quality of display unit, extend the service life of display unit; And pixel-driving circuit of the present invention is simple in structure, by the synergy of transistor AND gate electric capacity, improve the reliability of pixel-driving circuit.

Claims

1. a pixel-driving circuit, is characterized in that: comprising: constant-current source signal (I1), the first sweep signal (V1), the second sweep signal (Vs), power line (Vdd), ground wire (GND), the first transistor (T1), transistor seconds (T2), the 3rd transistor (T3), the 4th transistor (T4), the 5th transistor (T5), the first electric capacity (C1), the second electric capacity (C2) and Organic Light Emitting Diode (OLED);

Described the first transistor (T1) comprises first grid (g1), the first source electrode (s1), the first drain electrode (d1), described transistor seconds (T2) comprises second grid (g2), the second source electrode (s2), the second drain electrode (d2), described the 3rd transistor (T3) comprises the 3rd grid (g3), the 3rd source electrode (s3), the 3rd drain electrode (d3), described the 4th transistor (T4) comprises the 4th grid (g4), the 4th source electrode (s4), the 4th drain electrode (d4), described the 5th transistor (T5) comprises the 5th grid (g5), the 5th source electrode (s5), the 5th drain electrode (d5),

Described the first source electrode (s1) is electrically connected at constant-current source signal (I1), described second grid (g2) is electrically connected at first grid (g1), and second sweep signal (Vs), described the first drain electrode (d1) is electrically connected at the 4th grid (g1), the 3rd grid (g3), and one end of the first electric capacity (C1), described the second source electrode (s2) is electrically connected at constant-current source signal (I1), described the second drain electrode (d2) is electrically connected at the 4th drain electrode (d4), the 3rd source electrode (s3), described the 3rd drain electrode (d3) is electrically connected at the anode of Organic Light Emitting Diode (OLED), one end of the second electric capacity (C2), described the 4th source electrode (s4) is electrically connected at the other end of the first electric capacity (C1), the 5th source electrode (s5), and power line (Vdd), the minus earth (GND) of described Organic Light Emitting Diode (OLED), described the 3rd grid (g3) is electrically connected at the first sweep signal (V1), described the 5th drain electrode (d5) is electrically connected at the other end of the second electric capacity (C2).

2. pixel-driving circuit as claimed in claim 1, is characterized in that: described the 3rd transistor (T3) is driving tube.

3. pixel-driving circuit as claimed in claim 1, is characterized in that: described the first transistor (T1), transistor seconds (T2), the 4th transistor (T4) and the 5th transistor (T5) are switching tube.

4. pixel-driving circuit as claimed in claim 1, is characterized in that: described the first transistor (T1), transistor seconds (T2), the 3rd transistor (T3), the 4th transistor (T4) and the 5th transistor (T5) are thin film transistor (TFT).