Display Panel Pixel Circuit With Leakage-Current Compensation
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Solution Overview
Problem
Reducing the operating frequency of display panels to achieve a lighter and thinner design leads to unstable leakage currents, causing flickering and uneven brightness due to unstable voltages in the pixel circuit.
Innovation Solution
The pixel circuit incorporates a driving transistor, data write-in circuit, compensation circuit, voltage control circuit, and light-emitting switch to stabilize the leakage current by adjusting the voltage difference between the control and relay ends, using switches and impedance providers to create a stable driving current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If the operating frequency is reduced to achieve a lighter and thinner display panel design, then the weight and thickness are improved, but the leakage current becomes unstable causing flicker and uneven brightness
Solution Approach 1:
The compensation circuit performs preliminary compensation of the leakage current before the light emission phase. By compensating the voltage at the control end of the driving transistor in advance (during the compensation period before emission), the circuit pre-corrects for the unstable leakage current that would otherwise cause brightness instability, thus resolving the contradiction between low-frequency operation and brightness stability
Solution Approach 2:
The compensation circuit uses feedback mechanisms to detect and correct the leakage current. The circuit monitors the voltage at the control end of the driving transistor and adjusts the compensation voltage accordingly, creating a closed-loop system that maintains stable brightness despite the unstable leakage current inherent in low-frequency operation
2Length of stationary object
If the operating frequency is reduced to achieve a lighter and thinner display panel design, then the weight and thickness are improved, but the voltage inside the circuit becomes unstable leading to uneven brightness
Solution Approach 1:
The compensation circuit acts as an intermediary between the unstable voltage source (driving transistor with leakage current) and the light-emitting element. By introducing this intermediate compensation stage, the circuit mediates the voltage instability and delivers a stable voltage to the light-emitting element, thus resolving the contradiction between thin design and voltage stability
Solution Approach 2:
The voltage control circuit changes the voltage parameter dynamically to compensate for instability. By adjusting the voltage at the control end of the driving transistor based on the compensation signal, the circuit maintains stable operating conditions despite the inherent voltage instability in low-frequency operation, resolving the contradiction between thin design and voltage stability
Data Source
AI summary
Disclosed are a display panel and a pixel circuit thereof. The pixel circuit includes a driving transistor, a data write-in circuit, a compensation circuit, a voltage control circuit, a light-emitting switch, and a light-emitting element. The driving transistor receives a power supply voltage. The data write-in circuit receives a first scanning signal, an emission signal, and a write-in data signal, stores the write-in data signal, and provides the write-in data signal to a control end of the driving transistor. The compensation circuit has a first switch and a second switch coupled to a relay end and controlled by a second scanning signal. The voltage control circuit adjusts a voltage difference between the control end of the driving transistor and the relay end. The light-emitting switch is coupled between a second end of the driving transistor and the light-emitting element, and is controlled by the emission signal.