Display Drive Method for Large Panel Line Load Compensation
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Solution Overview
Problem
Large display panels face challenges in achieving highly accurate image displaying due to the influence of line load, making it difficult to control shift amount correction and maintain image accuracy.
Innovation Solution
A drive method for display devices that includes a light-emitting element, a capacitor, and specific switches to manage voltage and current flow, with initialization and threshold voltage compensation periods, allowing for precise control of the drive transistor and accurate image display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display panel size is increased, then the display area is improved, but the image display accuracy deteriorates due to line load influence
Solution Approach 1:
The patent divides the pixel circuit into multiple functional blocks: drive transistor, switching transistor, capacitor, and compensation circuit. This segmentation allows independent optimization of each block to maintain accuracy across large display areas despite line load variations.
Solution Approach 2:
The patent implements preliminary threshold voltage compensation before the display period using a compensation transistor and capacitor. This preliminary action corrects drive transistor characteristics in advance, ensuring accurate image display across the entire panel including large areas where line load effects are significant.
2Manufacturing precision
If threshold voltage compensation is applied, then the image display accuracy is improved, but the control complexity increases for large display panels
Solution Approach 1:
The patent combines the threshold voltage compensation function with the existing pixel circuit structure by integrating a compensation transistor and capacitor into the pixel circuit. This merging achieves accurate compensation without adding separate complex control systems, thereby improving image display accuracy while controlling complexity.
Solution Approach 2:
The pixel circuit performs self-compensation of threshold voltage variations through its internal compensation transistor and capacitor during the compensation period. This self-service mechanism eliminates the need for external complex control systems, maintaining image display accuracy across large panels while minimizing control complexity.
3Illumination intensity
If the drive current is increased to improve luminance, then the brightness is improved, but the threshold voltage variation of the drive transistor increases
Solution Approach 1:
The patent implements a feedback mechanism where the compensation transistor senses the threshold voltage of the drive transistor and adjusts the capacitor charge accordingly during the compensation period. This feedback loop maintains threshold voltage stability even when drive current increases to improve luminance, ensuring consistent image quality across the display panel.
Solution Approach 2:
The patent performs threshold voltage compensation in advance during the compensation period before the display period begins. This preliminary action establishes stable operating conditions for the drive transistor, allowing higher drive currents to be used for improved luminance without causing threshold voltage variations that would degrade image quality.
Data Source
AI summary
By a drive method, for each of a plurality of display pixels each including an EL element, a capacitor, a drive transistor, an enable switch, and a switch, a period T21 is started by switching only the enable switch to an electrically conductive state before a period T22 in which the drive transistor is initialized, and the period T22 following the period T21 is started by switching the switch to an electrically conductive state. The period T21 is longer than a period T24 in which a threshold voltage of the drive transistor is compensated.