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OLED pixel circuit and its display device

A pixel circuit and electrode technology, which is applied in the field of OLED pixel circuits and display devices, can solve the problems of uneven light emission, uneven light emission of display panels, inconsistent brightness of OLED devices, etc., and achieve the effect of compensation for uneven light emission

Active Publication Date: 2017-05-31
BOE TECH GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] In the existing TFT-OLED pixel circuit, there are OLED current changes caused by uncontrollable factors such as process instability, parameter drift, and device aging of TFT and OLED light-emitting devices, which in turn leads to uneven light emission of the display panel.
[0003] In order to solve the problem of uneven luminescence, the existing electrical compensation methods usually use the detection of the voltage / current signal acting on the OLED to compensate
This compensation method can usually solve the problem of uneven luminescence caused by changes in the characteristics of the TFT drive tube, but it cannot solve the problem of inconsistent brightness caused by the aging of the OLED device itself or the difference in characteristics, even if the passing current of each OLED is constant. compensate

Method used

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  • OLED pixel circuit and its display device

Examples

Experimental program
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Effect test

Embodiment 1

[0045] This embodiment provides an OLED pixel circuit, which uses a positive coefficient photoresistor to compensate the driving circuit of the N-type thin film transistor. The specific circuit structure is as follows: figure 1 , 2 shown.

[0046] In the OLED pixel circuit, the sensing element is a photoresistor, and the compensation unit also includes a synchronous transistor, a compensation drive tube and a voltage dividing resistor, wherein:

[0047] The photoresistor and the voltage dividing resistor are connected in series to form a series branch, the first end of the series branch is a constraint end and is connected to the synchronous transistor, and the second end is a free end and is connected to the second reference voltage end. figure 1 Among them, one end of the photoresistor R1 in the series branch is a constraint end and is connected to the first pole of the synchronous transistor S2, and one end of the voltage dividing resistor R2 in the series branch is a free...

Embodiment 2

[0064] This embodiment provides an OLED pixel circuit, which uses a negative coefficient photoresistor to compensate the driving circuit of the N-type thin film transistor. The specific circuit structure is as follows: image 3 , 4 shown.

[0065] In the OLED pixel circuit, the synchronous transistor S2 and the compensating driving tube TFT2 are N-type thin film transistors, and the photosensitive resistor R1 is a negative coefficient photosensitive resistor whose resistance value decreases with the enhancement of the OLED brightness, and the free end of the series branch is the photosensitive resistor R1 One end of the voltage dividing resistor R2 is not connected. For negative coefficient photoresistors, the resistance value shows a large resistance value under the condition of no light; under the condition of light, the resistance value becomes smaller and the resistance value becomes smaller as the light increases.

[0066] image 3 Shown is a structure in which N-type ...

Embodiment 3

[0076] This embodiment provides an OLED pixel circuit, which uses a positive coefficient photoresistor to compensate the driving circuit of the P-type thin film transistor. The specific circuit structure is as follows: Figure 5 , 6 shown.

[0077] In the OLED pixel circuit, the synchronous transistor S2 and the compensating driving tube TFT2 are P-type thin film transistors, the photoresistor R1 is a positive-coefficient photoresistor whose resistance value increases with the brightness of the OLED, and the free end of the series branch is the photoresistor R1 One end of the voltage dividing resistor R2 is not connected.

[0078] Figure 5Shown is a structure in which a P-type thin film transistor is used in the OLED pixel circuit, and the compensation unit uses a positive coefficient photoresistor R1 to measure light on the OLED; in the drive unit, the first pole of the output transistor TFT1 is connected to the first input voltage terminal and the storage capacitor The s...

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Abstract

An OLED pixel circuit and a display apparatus comprising the OLED pixel circuit. An OLED pixel circuit comprises an OLED and driving units (TFT1, S1, C) for driving the OLED to emit light, wherein one electrode of the OLED is connected to the driving units (TFT1, S1, C). The OLED pixel circuit further comprises compensation units (R1, S2, TFT2, R2). The compensation units (R1, S2, TFT2, R2) comprises a sensing element (R1) which can sense light and convert an optical signal of the OLED into an electrical signal. The compensation units (R1, S2, TFT2, R2) compensate for currents used by the driving units (TFT1, S1, C) to drive the OLED according to the light-emitting brightness of the OLED.

Description

technical field [0001] The invention belongs to the field of display technology, and in particular relates to an OLED pixel circuit and a display device thereof. Background technique [0002] In the existing TFT-OLED pixel circuit, there are changes in OLED current caused by uncontrollable factors such as process instability, parameter drift and device aging of TFT and OLED light-emitting devices, which in turn leads to uneven light emission of the display panel. [0003] In order to solve the problem of non-uniform luminescence, the existing electrical compensation methods usually use detection of voltage / current signals acting on the OLED to perform compensation. This compensation method can usually solve the problem of uneven luminescence caused by changes in the characteristics of the TFT drive tube, but it cannot solve the problem of inconsistent brightness caused by the aging of the OLED device itself or the difference in characteristics, even if the passing current of...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G09G3/3208H01L27/32
CPCG09G3/3233G09G3/32G09G3/3208G09G2300/0842G09G2310/0251G09G2310/0262G09G2320/0233G09G2320/043G09G2320/045G09G2360/145
Inventor 宋琛
Owner BOE TECH GRP CO LTD
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