Shift Register Random Compensation for OLED Display Uniformity
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Solution Overview
Problem
In OLED display panels, sequential row-by-row compensation methods lead to display failure issues such as scan lines and uneven brightness due to timing differences in external compensations, which are more pronounced in large-sized displays.
Innovation Solution
A shift register with a compensation selection circuit, holding circuit, and multiple shift register circuits that provide a blanking pull-down signal and drive signals to nodes, allowing for random compensation of sub-pixels and reducing the complexity of the gate driving circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sequential row-by-row compensation method is used, then the gate driving circuit can be implemented, but display failures and uneven brightness occur due to timing differences in external compensations
Solution Approach 1:
The patent implements dynamic compensation timing by enabling random selection of compensation rows through the compensation selection circuit (100). Instead of fixed sequential compensation, the system dynamically chooses which rows receive compensation signals based on actual display needs, eliminating timing-related display failures and uneven brightness while maintaining circuit simplicity
Solution Approach 2:
The patent changes the timing parameter of compensation operations from fixed sequential to random variable timing. By using the compensation selection control signal (OE) to randomly enable different shift register circuits at different times, the system achieves uniform display output without the timing differences that cause display failures, while keeping the circuit configuration simple
2Productivity
If gate driving circuit is integrated in gate driving chip, then scanning function is achieved, but chip area increases due to complicated structure including sensing circuit, scanning circuit, and connection circuit
Solution Approach 1:
The patent extracts the sensing circuit function from the gate driving chip and relocates it to the array substrate. The shift register circuits (300_1 to 300_N) are configured to directly drive sensing transistors on the array substrate, eliminating the need for separate sensing circuits in the chip. This reduces chip area while maintaining the complete scanning and sensing functionality
Solution Approach 2:
The shift register circuits are designed with multi-functionality, serving both as scanning drivers and sensing drivers. By using the same shift register circuits to provide both display signals and compensation signals to different rows at different times, the patent eliminates the need for separate dedicated sensing circuits, connection circuits, and OR circuits, thereby reducing chip area while maintaining full functionality
Data Source
AI summary
A shift register is provided, which may include a compensation selection circuit, a holding circuit, and N shift register circuits. The hold circuit may hold a blanking input signal. Each of the shift register circuits may include a blanking input circuit and an output circuit. The blanking input circuit may provide a blanking pull-down signal to a first node according to the blanking input signal and a blanking control signal. The output circuit may output a shift signal via a shift signal output terminal and output a first drive signal via a first drive signal output terminal according to a voltage of the first node. The compensation selection circuit may provide, according to a compensation selection control signal and the shift signal from one of the N shift register circuits, the blanking input signal to the holding circuit and the N shift register circuits.