Display Panel Memory Circuit Segmentation for Luminance Correction
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Solution Overview
Problem
Active-matrix organic EL display units face challenges in achieving high correction capability for irregular emission luminance due to variations in threshold voltage and mobility of driving transistors, leading to impaired screen uniformity.
Innovation Solution
A display panel with a pixel circuit configuration that includes a driving transistor, a memory circuit, a writing transistor, and storage capacitors, where the memory circuit has a second storage capacitor and switching transistors are strategically placed to minimize parasitic capacitance and enhance bootstrap gain, allowing for improved threshold and mobility corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional memory circuit configuration is used, then the circuit is simpler, but the correction capability for irregular emission luminance is insufficient
Solution Approach 1:
The memory circuit is segmented into multiple functional components: a first storage capacitor (Cs1) for holding signal voltage, a second storage capacitor (Cs2) for holding correction voltage, and multiple switching transistors (Tr3, Tr4) for controlled charge transfer. This segmentation allows independent optimization of signal storage and correction functions, improving correction capability while maintaining manageable circuit complexity.
Solution Approach 2:
The second storage capacitor (Cs2) acts as an intermediary element that temporarily stores correction voltages generated during the correction period. This intermediary capacitor enables the correction operation to be decoupled from the signal display period, allowing thorough correction without compromising the signal integrity displayed during emission.
2Duration of action of moving object
If the emission time is extended, then the display can show content longer, but flickering occurs
Solution Approach 1:
The correction operation is performed preliminarily during a correction period before the emission period begins. By completing the threshold voltage and mobility correction in advance using the second storage capacitor (Cs2), the driving transistor is pre-adjusted to compensate for irregularities, ensuring stable emission throughout the extended display duration without flickering.
3Length of moving object
If the bezel width is reduced, then the display appears more modern, but the correction circuit space is limited
Solution Approach 1:
The first storage capacitor (Cs1) and second storage capacitor (Cs2) are merged into a single memory circuit block within the pixel, sharing common circuit elements and space. The switching transistors (Tr3, Tr4) are integrated with the driving transistor gate control, consolidating the correction functionality within the existing pixel structure rather than requiring separate dedicated correction circuitry, thus minimizing the area occupied.
Data Source
AI summary
A display panel according to an embodiment of the technology is provided with a plurality of pixels. The pixels each include a light-emitting device and a pixel circuit. Each pixel circuit includes a memory circuit. The memory circuit includes a storage capacitor and a first switching transistor. The storage capacitor is configured to store a signal voltage. The first switching transistor is provided between a gate of a driving transistor and the storage capacitor. The memory circuit further includes a second switching transistor. The second switching transistor is provided between the storage capacitor and the first switching transistor, or provided on side opposite to the first switching transistor with respect to the storage capacitor.