OLED Pixel Circuit Voltage Feedback for Luminance Compensation
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Solution Overview
Problem
Existing image display apparatus with organic EL elements face luminance nonuniformity due to threshold voltage fluctuations and OLED degradation over time, requiring complex external circuits for compensation.
Innovation Solution
An image display apparatus with a pixel circuit that includes a light emitting element, a driver, and a control circuit capable of detecting the voltage applied to the light emitting element and feeding back the detected voltage to the driver during light emission, allowing for real-time compensation of luminance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex external circuits are used to detect and compensate luminance changes, then luminance uniformity is improved, but device complexity increases
Solution Approach 1:
The patent merges the luminance compensation function into the pixel-level control circuit, combining the detection and compensation operations within the existing pixel structure. This eliminates the need for separate external compensation circuits while maintaining luminance uniformity across the display.
Solution Approach 2:
The control circuit performs self-detection and self-compensation of luminance changes by monitoring the voltage applied to the light emitting element and adjusting the driving voltage accordingly. This self-service mechanism eliminates the need for external compensation circuits.
2Reliability
If real-time voltage detection and feedback is implemented, then luminance change compensation is improved, but ease of operation deteriorates
Solution Approach 1:
The control circuit implements a feedback mechanism that continuously monitors the voltage applied to the light emitting element during light emission and adjusts the driving voltage based on the detected voltage. This automatic feedback loop maintains accurate luminance compensation without requiring manual intervention or complex operational procedures.
Data Source
AI summary
Disclosed is an image display wherein luminance change due to change of the light-emitting device over time is compensated while suppressing affects of characteristics change in the drive transistor. Specifically disclosed is an image display comprising a plurality of pixels, wherein each pixel has a light-emitting device (OLED) which emits light when current is passed therethrough, a driver device (Td) for controlling light emission of the light-emitting device, and a control circuit (A) which is electrically connected to the light-emitting device and the driver device, and directly or indirectly detects the voltage applied to the light-emitting device at least during when the light-emitting device is emitting light and reflects the detection results to the driver device.