CN101859543B - Method for improving brightness uniformity of AMOLED panel - Google Patents

Abstract

The invention relates to an OLED display technology, in particular to a method for improving the brightness uniformity of an AMOLED panel. The invention discloses the method for improving the brightness uniformity of the AMOLED panel, which solves the problem of poor brightness uniformity of the AMOLED panel in a traditional technology. The technical scheme of the invention has the following key points of: (a) adding a voltage conversion circuit in a driving chip of the AMOLED panel; (b) obtaining a corresponding data signal parameter when conforming to the brightness requirement of the AMOLED panel, and storing the corresponding data signal parameter in the driving chip; (c) inputting the input signal of a pixel point as an addressing signal to the voltage conversion circuit; and (d) invoking the data signal parameter corresponding to the pixel point and converting the data signal parameter into a driving signal by the voltage conversion circuit. The invention has the advantages of good brightness uniformity of the AMOLED panel, simple realization and low cost.

Description

A kind of inhomogeneity method of AMOLED panel luminance of improving

Technical field

The present invention relates to the OLED display technique, relate to the inhomogeneity method of a kind of AMOLED of improvement panel luminance specifically.

Background technology

Traditional 2T1C (two transistors and an electric capacity) pixel cell driving circuit based on N type TFT constitutes is as shown in Figure 1.Among the figure, the M1 pipe is controlled by horizontal scanning line Vscan for switching tube, and purpose is the input for control data voltage Vdata; The M2 pipe is driving tube, and control OLED (Organic Light Emitting Diode) is luminous; Cs is a MM CAP, for the grid of M2 provides biasing and keeps voltage.

This drive circuit works period is divided into two parts in the single scan period: first is video data write time t1, and in the write time, horizontal scanning line is a high level at video data.This moment, M1 was operated under the on off state, and data-signal stores on the capacitor C s through the passage between the drain-source of M1 pipe, and this voltage acts on the grid of M2 pipe, makes M2 be operated under the state of saturation, and driving OLED is luminous.Second portion is for showing the t2 that holds time, and horizontal scanning line is a low level, and M1 is under the cut-off state, and the passage between the drain-source is turned off, and data-signal also just can not pass to the grid of M2, i.e. the two ends of electric capacity.At this moment, capacitor C s two ends remain on by preceding state owing to the shutoff of M1 do not had the to release path of electric charge, make M2 still be under the state of saturation, and it is luminous to continue to keep OLED.No matter at video data in the write time; Still in demonstration is held time; The Cs voltage remains unchanged in theory, that is to say that the luminous of OLED remained unchanged in this frame period always, this state last till always image element circuit next frame in the time by gating once more.But in practical engineering application, because process conditions and horizontal constraints have caused the dispersiveness of TFT characteristic, thereby caused the threshold voltage of each pixel drive TFT pipe (M2 pipe) inconsistent, the brightness uniformity that finally shows as entire display screen is poor.

For eliminating or to improve the TFT threshold voltage inconsistent to the inhomogeneity influence of brightness of display screen; People have proposed some solutions; These schemes are divided into two types: one type is to improve process, raising technological level, improves the consistance of M2 pipe threshold voltage, thereby improves the problem of brightness uniformity.This method has obtained certain effect, but this method need be developed new process, and the very big or production cost of difficulty increases considerably; Another kind of is on former 2T1C circuit, to improve; Reduce or eliminate the inconsistent influence of threshold voltage; Effect is also apparent in view; But, require higher and pixel aperture ratio reduction fast to processing technology, thereby influence display performance (like life-span, efficient etc.) along with the increase of pixel-driving circuit complexity.It is exactly all on AMOLED (active-matrix Organic Light Emitting Diode) panel, to implement that these solutions have a common characteristic; Because the technology of AMOLED panel itself is mature and stable not enough; These measures have further improved it and have manufactured and designed difficulty and cost, and becoming is difficult to carry out.

Summary of the invention

Technical matters to be solved by this invention is: propose the inhomogeneity method of a kind of AMOLED of improvement panel luminance, solve the problem of AMOLED panel luminance lack of homogeneity in the conventional art.

The present invention solves the problems of the technologies described above the technical scheme that is adopted: the inhomogeneity method of a kind of AMOLED of improvement panel luminance may further comprise the steps:

A. in the chip for driving of AMOLED panel, increase voltage conversion circuit;

B. obtain the pairing data-signal parameter of AMOLED panel luminance, and be stored in the chip for driving;

C. the input signal with pixel inputs to voltage conversion circuit as address signal;

D. call the corresponding data-signal parameter of this pixel and convert drive signal into through voltage conversion circuit;

Among the said step b, the method for obtaining the pairing data-signal parameter of AMOLED panel luminance is:

B1. series resistor R1 between driving tube in pixel-driving circuit and the power supply;

B2. require to confirm that according to the AMOLED panel luminance different GTGs pass through the electric current I s of OLED down;

B3. the corresponding voltage Vs at calculated resistance R1 two ends;

B4. regulate the pixel-driving circuit applied signal voltage and make that the test voltage at resistance R 1 two ends is Vs;

B5. the magnitude of voltage that reads pixel-driving circuit input signal this moment is the pairing data-signal parameter of AMOLED panel luminance.

The invention has the beneficial effects as follows: implementation is simple, cost is low, and effect is remarkable.

Description of drawings

Fig. 1 is a 2T1C pixel cell driving circuit;

Fig. 2 is the metering circuit of pixel cell driving circuit TFT drive characteristic;

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is done further description.

In order to solve the problem of AMOLED panel luminance lack of homogeneity in the conventional art, the present invention proposes the inhomogeneity method of a kind of AMOLED of improvement panel luminance.With respect to conventional art; Main inventive point of the present invention is: abandoned the improved mode of directly on the AMOLED panel, doing; And through its drive IC being increased voltage conversion circuit, change the drive signal voltage of image element circuit reached and improve the inhomogeneity purpose of panel luminance.

Implementation step is following: a. increases voltage conversion circuit in the chip for driving of AMOLED panel; B. obtain pairing data-signal parameter when meeting the requirement of AMOLED panel luminance, and be stored in the chip for driving; C. the input signal with pixel inputs to voltage conversion circuit as address signal; D. call the corresponding data-signal parameter of this pixel and convert drive signal into through voltage conversion circuit.

Embodiment:

In drive IC, increase voltage conversion circuit; Obtain pairing data-signal parameter when meeting the requirement of AMOLED panel luminance; And be stored in the chip for driving: as shown in Figure 2; Increase resistance R 1 between driving tube M2 in pixel-driving circuit and the power vd D, require to confirm different GTGs down through the size of current Is of OLED according to the AMOLED panel luminance, S is grey exponent number; That so just can calculate when OLED reaches regulation brightness resistance R 1 two ends should have magnitude of voltage Vs=Is * R1; The size that regulate the input signal Vdata of image element circuit this moment; Make that the magnitude of voltage at resistance R 1 two ends is Vs; Read the image element circuit input signal Vdatas of this moment, and this magnitude of voltage is saved in the drive IC as the data-signal parameter that meets AMOLED panel luminance when requirement; When the AMOLED panel is driven; Original input signal Vdata only inputs to voltage conversion circuit as address signal; Read out its corresponding data-signal parameter (perhaps being called and this pixel TFT characteristic matching parameter) Vdatas when meeting the AMOLED panel luminance and requiring; Voltage conversion circuit can be with voltage transitions to Vdatas, can make that as the drive signal of AMOLED panel brightness is even with this magnitude of voltage.

Illustrate: suppose pixel P ₁, P ₂, P ₃Input signal Vdata ₁=Vdata ₂=Vdata ₃The time, because the threshold voltage vt h of the corresponding driving tube M2 of these three pixels ₁≠ Vth ₂≠ Vth ₃Adopt traditional 2T1C pixel-driving circuit, when in the drive IC during no-voltage change-over circuit, the brightness L of three pixels ₁≠ L ₂≠ L ₃And after adopting above-mentioned voltage conversion circuit in the drive IC, Vdata ₁, Vdata ₂, Vdata ₃Direct driving pixels circuit, but be addressed to the Vdatac that matees with these three pixel drives characteristics ₁, Vdatac ₂, Vdatac ₃Though, Vdatac ₁≠ Vdatac ₂≠ Vdatac ₃But corresponding identical brightness.Like this with Vdata ₁, Vdata ₂, Vdata ₃Convert Vdatac into ₁, Vdatac ₂, Vdatac ₃Remove the driving pixels circuit as input signal, just obtained the brightness L of above-mentioned three points ₁=L ₂=L ₃

Belong to ripe prior art for the voltage conversion circuit described in the present invention, no longer its concrete structure is given unnecessary details here.

Claims (1)

1. one kind is improved the inhomogeneity method of AMOLED panel luminance, it is characterized in that: may further comprise the steps:

A. in the chip for driving of AMOLED panel, increase voltage conversion circuit;

B. obtain the pairing data-signal parameter of AMOLED panel luminance, and be stored in the chip for driving;

C. the input signal with pixel inputs to voltage conversion circuit as address signal;

D. call the corresponding data-signal parameter of this pixel and convert drive signal into through voltage conversion circuit;

Among the said step b, the method for obtaining the pairing data-signal parameter of AMOLED panel luminance is:

B1. series resistor R1 between driving tube in pixel-driving circuit and the power supply;

B2. confirm to pass through under the different GTGs electric current I s of OLED according to the AMOLED panel luminance;

B3. the corresponding voltage Vs at calculated resistance R1 two ends;

B4. regulate the pixel-driving circuit applied signal voltage and make that the test voltage at resistance R 1 two ends is Vs;

B5. the magnitude of voltage that reads pixel-driving circuit input signal this moment is the pairing data-signal parameter of AMOLED panel luminance.

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