Pixel Circuit Compensation Module for OLED Luminance Uniformity
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Solution Overview
Problem
Existing organic light-emitting display devices experience uneven display luminance due to power supply voltage drops, resulting in different currents flowing through light-emitting diodes.
Innovation Solution
A pixel circuit with a compensation module that uses a storage capacitor and thin film transistors to apply a compensation voltage independent of the power supply voltage, ensuring consistent current flow through light-emitting diodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If power supply voltage is transmitted between multiple pixel circuits, then power supply can be shared across the display device, but power supply voltage drop (IR drop) is generated resulting in different actual power supply voltages and uneven display luminance
Solution Approach 1:
Each pixel circuit is equipped with its own compensation module that locally compensates for the power supply voltage drop specific to that circuit. This local compensation approach allows each pixel circuit to independently adjust its drive transistor gate voltage to account for its specific IR drop, thereby maintaining uniform display luminance across the entire display device while sharing the common power supply.
2Manufacturing precision
If compensation module is added to each pixel circuit, then power supply voltage drop can be compensated, but device complexity increases
Solution Approach 1:
The compensation module uses a standardized configuration of transistors and capacitors that can be uniformly implemented across all pixel circuits. This universal design allows the same circuit topology to perform multiple functions: threshold voltage compensation, power supply voltage drop compensation, and current control, thereby reducing overall complexity despite adding compensation capabilities to each pixel circuit.
Data Source
AI summary
The application discloses a pixel circuit and a driving method thereof, a display device. The pixel circuit includes a first through seventh thin film transistor, a light-emitting diode, a storage capacitor and a compensation module. A gate of the first thin film transistor is separately connected to a source of the third and fourth thin film transistor and one end of the storage capacitor, a drain of the fourth thin film transistor is connected to a reference voltage signal line; source of the first thin film transistor is separately connected to a drain of the second and fifth thin film transistor and a source of the seventh thin film transistor; a drain of the first thin film transistor is separately connected to a drain of the third thin film transistor and a source of the sixth thin film transistor.