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Pixel circuit, driving method thereof, and display device

A pixel circuit and drive transistor technology, applied in static indicators, instruments, etc., can solve the problems of current-limited pixel circuit application, fast driving speed, long settling time, etc.

Active Publication Date: 2017-10-24
PEKING UNIV SHENZHEN GRADUATE SCHOOL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The compensation accuracy of the current-type pixel circuit is relatively high, but it needs a relatively long settling time, especially in the case of low current and large parasitic capacitance on the data line
This severely limits the application of current-mode pixel circuits in large-area, high-resolution displays
The compensation accuracy of the voltage-type pixel circuit is not as high as that of the current-type pixel circuit, and the circuit structure or / and driving signal are generally relatively complicated, but the driving speed is fast
How to better sense the unevenness or drift of the threshold voltage of the driving transistor T1 and compensate for it, so as to reduce the display unevenness caused by the threshold voltage has become an urgent problem to be solved

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Please refer to figure 2 , The structure diagram of a pixel circuit disclosed in this embodiment, the pixel circuit is used to arrange scan lines arranged in a first direction for providing scan signals and data lines arranged in a second direction for providing data signals In this embodiment, the first level terminal is the low level terminal V SS Or ground, the second level terminal is the high level terminal V DD , The pixel circuit includes: a driving transistor T1, a light emitting element OLED, a storage capacitor Cs, a second transistor T2, a third transistor T3, a fourth transistor T4, a fifth transistor T5, and a sixth transistor T6, wherein,

[0030] The control electrode of the driving transistor T1 is coupled to the control electrode of the second transistor T2, such as figure 2 As shown, the coupling node is the first node A; the second pole of the driving transistor T1 is coupled to the second terminal of the light-emitting element OLED; the first terminal...

Embodiment 2

[0051] Different from the foregoing embodiment, in the pixel circuit disclosed in this embodiment, each transistor is a P-channel thin film transistor, and the effective level of each transistor being turned on is a low level. Please refer to Figure 4 , Is a structural diagram of a pixel circuit disclosed in this embodiment.

[0052] The control electrode of the driving transistor T1 is coupled to the control electrode of the second transistor T2, and the coupling node is the first node A; the second electrode of the driving transistor T1 is coupled to the second end of the light-emitting element OLED; the first end of the light-emitting element OLED is used for Coupled to the low level terminal V SS , The first pole of the driving transistor T1 is used to couple to the high-level terminal V DD . In this embodiment, the first end of the light-emitting element OLED is the cathode, and the second end is the anode.

[0053] The first end of the storage capacitor Cs is coupled to t...

Embodiment 3

[0068] Please refer to Image 6 , This embodiment discloses a structure diagram of a pixel circuit. The difference from the second embodiment is that, in the pixel circuit of this embodiment, the driving transistor T1 and the second transistor T2 are P-channel thin film transistors, and the third transistor T3, The fourth transistor T4, the fifth transistor T5 and the sixth transistor T6 are all N-channel thin film transistors. The effective level when the driving transistor T1 and the second transistor T2 are turned on is a low level; the effective level when the third transistor T3, the fourth transistor T4, the fifth transistor T5, and the sixth transistor T6 are turned on is a high level.

[0069] The control electrode of the driving transistor T1 is coupled to the control electrode of the second transistor T2, and the coupling node is the first node A; the second electrode of the driving transistor T1 is coupled to the second end of the light-emitting element OLED; the first ...

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Abstract

A pixel circuit and its driving method are provided. In the initialization phase, the third transistor is turned on, and the potentials of the electrodes of the second transistor are initialized; in the programming phase, the threshold voltage and the data signal of the second transistor are stored in the storage capacitor, and the threshold voltage can be Characterize the threshold voltage of the driving transistor; in the light-emitting stage, the driving transistor is driven to generate a driving current according to the voltage difference across the storage capacitor, and drives the light-emitting element to emit light. Since the position of the second transistor and the driving transistor in the pixel circuit are close and the gate voltage is the same, the source voltage is consistent when emitting light, and the second transistor can mirror the initial threshold voltage of the driving transistor and its threshold voltage drift after use. In the programming stage, the threshold voltage is stored by the storage capacitor, so that the problem of uneven threshold voltage or threshold voltage drift of the driving transistor can be compensated in the light emitting stage. A display device is also provided.

Description

Technical field [0001] This application relates to the field of display devices, in particular to a pixel circuit and a driving method thereof, and a display device. Background technique [0002] Organic Light-Emitting Diode (OLED) displays have been widely studied in recent years due to their advantages of high brightness, high luminous efficiency, wide viewing angle, and low power consumption, and they have been rapidly applied to a new generation of displays. The driving mode of the OLED display can be passive matrix driving (Passive Matrix OLED, PMOLED) and active matrix driving (Active Matrix OLED, AMOLED). Although the cost of passive matrix driving is low, high-resolution display cannot be achieved due to the phenomenon of crosstalk, and the passive matrix driving current is large, which reduces the service life of the OLED. In contrast, the active matrix driving method sets a different number of transistors on each pixel as a current source, avoiding crosstalk, requiring...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G09G3/3233
Inventor 林兴武张盛东孟雪冷传利王翠翠
Owner PEKING UNIV SHENZHEN GRADUATE SCHOOL
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