External AMOLED Compensation Circuit for Aperture Ratio
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Solution Overview
Problem
Existing AMOLED compensating circuits require multiple thin film transistors within pixel regions, reducing the aperture ratio due to the need for additional components to manage threshold voltage variations.
Innovation Solution
An AMOLED driving and compensating circuit with an external compensating circuit outside the pixel regions, utilizing a specific configuration of transistors and capacitors to eliminate threshold voltage effects on driving currents, allowing only a single driving circuit per pixel region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a compensating circuit is added inside the pixel region to eliminate threshold voltage effects, then luminance uniformity is improved, but aperture ratio is reduced due to additional transistors occupying space
Solution Approach 1:
The patent divides the compensating circuit into two parts: a simple driving circuit inside the pixel region (using only 1-2 transistors) and a complex compensating circuit outside the pixel region (using multiple transistors). This segmentation allows the pixel region to maintain high aperture ratio while the external circuit provides threshold voltage compensation for improved luminance uniformity.
Solution Approach 2:
The patent moves the compensating circuit from the two-dimensional plane inside the pixel region to an external location, effectively using the third dimension (spatial relocation) to resolve the contradiction. By placing the compensating circuit outside the pixel region, the aperture ratio is preserved while still achieving threshold voltage compensation.
2Reliability
If multiple transistors are used inside the pixel region for compensation, then threshold voltage effects are eliminated, but device complexity increases
Solution Approach 1:
The patent segments the circuit functions by placing only the essential driving transistors inside the pixel region and moving the compensating transistors outside. This reduces the number of transistors inside the pixel region from 5-6 to just 1-2, simplifying the device structure while maintaining compensation functionality externally.
Solution Approach 2:
The patent extracts the compensating circuit components (multiple transistors) from the pixel region and relocates them to an external position. This extraction reduces the transistor count inside the pixel region, lowering device complexity while the external circuit continues to provide threshold voltage compensation.
Data Source
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AI summary
The present disclosure discloses an AMOLED driving and compensating circuit and method, and AMOLED display device. The driving and compensating circuit comprising: several driving circuits set inside several pixel regions used for driving several AMOLEDs; an external compensating circuit set outside the pixel regions used for eliminating an effect of threshold voltage of a driving thin film transistors in the several driving circuits set inside the several pixel regions on driving currents passing through the driving thin film transistors. The driving and compensating method comprising: storing threshold voltage of the driving thin film transistors of the several driving circuits set inside the several pixel regions; storing grayscale voltage of each of the several driving circuits set inside the several pixel regions; gate voltage of the driving thin film transistor of each of the several driving circuits set inside the several pixel regions jumping to a sum of the threshold voltage and the grayscale voltage of the driving circuit. The display device comprises the AMOLED driving and compensating circuit.