Electroluminescent Pixel Circuit Pre-Compensation for Luminance Uniformity
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Solution Overview
Problem
Electroluminescent display apparatuses suffer from luminance deviations between pixels due to threshold voltage shifts caused by manufacturing variations and degradation over time, degrading display quality.
Innovation Solution
The apparatus includes a display panel with pixels containing a light emitting device, a driving element, switch elements, and a storage capacitor, which compensates for threshold voltage deviations through internal compensation operations using specific driving waveforms to stabilize the driving current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal compensation operations are implemented to stabilize driving current, then display quality is improved, but device complexity increases
Solution Approach 1:
The pixel circuit performs self-compensation for threshold voltage deviations using its own internal components (storage capacitor, switch elements) without requiring external compensation circuits. The driving element's threshold voltage deviation is compensated by adjusting the voltage across the storage capacitor during specific time periods, enabling the circuit to correct its own deficiencies.
Solution Approach 2:
The compensation operation is performed in advance during a first time period before the actual light emission period. The storage capacitor is charged to a voltage that pre-compensates for the threshold voltage deviation, so that when the driving element operates during the emission period, the compensation is already in place, stabilizing the driving current.
2Reliability
If multiple switch elements and storage capacitors are added per pixel, then threshold voltage compensation is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The invention changes the voltage parameter stored in the storage capacitor to compensate for threshold voltage deviations. By adjusting the voltage level across the storage capacitor based on the driving element's characteristics, the system compensates for manufacturing variations without requiring precise control of the physical dimensions or material properties of the additional components.
Data Source
AI summary
An electroluminescent display apparatus may include a display panel including a plurality of pixels, a gate driving circuit driving scan lines and emission lines connected to the plurality of pixels, and a data driving circuit driving data lines connected to the plurality of pixels. A first pixel arranged in an nth (where n is a natural number) pixel row among the pixels included in the display panel of the electroluminescent display apparatus may include a light emitting device, a driving element, a plurality of switch elements, and a storage capacitor.