OLED Pixel Compensation Circuit Using Segmented Light Emission
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Solution Overview
Problem
Existing display technologies using self-light-emitting elements like OLEDs face issues with luminance uniformity due to deterioration, leading to image sticking and false contours, as current compensation methods either cause unstable transistor operation or introduce unwanted contours.
Innovation Solution
A display apparatus with pixel circuits that include a light-emitting element, an optical sensor, and a compensation control circuit using multiple capacitors to control current supply based on luminance detection, dividing the light emission interval into segments to compensate for luminance deterioration while preventing false contours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current compensation methods are used to compensate for luminance deterioration, then luminance uniformity is improved, but false contours are introduced
Solution Approach 1:
The light emission interval is divided into multiple segments: a first light emission interval for normal display and a second light emission interval for compensation. This segmentation allows the display apparatus to control current supply differently during different time periods, compensating for luminance deterioration without affecting the overall image quality and preventing false contour generation.
2Manufacturing precision
If duty ratio control is used to compensate for luminance deterioration, then luminance uniformity is improved, but image quality deteriorates due to false contours
Solution Approach 1:
The light emission interval is divided into multiple segments: a first light emission interval for normal display and a second light emission interval for compensation. This segmentation allows the display apparatus to control current supply differently during different time periods, compensating for luminance deterioration without affecting the overall image quality and preventing false contour generation.
Solution Approach 2:
The patent applies different control strategies to different time intervals: during the first light emission interval, normal current control is applied for high-quality image display, while during the second light emission interval, compensated current control is applied to address luminance deterioration. This local differentiation ensures that compensation occurs without degrading overall image quality.
3Manufacturing precision
If transistors are operated in saturation region for current control, then current compensation is achieved, but operation stability deteriorates
Solution Approach 1:
The patent dynamically switches between different operating modes by dividing the light emission interval into segments. During the first interval, the system operates in normal mode with stable transistor operation, while during the second interval, it switches to compensation mode. This dynamic switching allows the system to achieve current compensation while maintaining overall operational stability through proper timing and control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively compensates for luminance deterioration in OLEDs, preventing image sticking and false contours by individually controlling current supply to each pixel, maintaining luminance uniformity and reducing the occurrence of unwanted visual artifacts.
Implementation Method 1
an optical sensor configured to detect the luminance of the light emitted from the light-emitting element
Data Source
AI summary
A display device includes pixel circuits arranged in a matrix, each of the pixel circuits including: a light-emitting element; an optical sensor to detect luminance of light emitted from the light-emitting element; and a compensation control circuit including a first capacitor and a second capacitor, the first and second capacitors to maintain a second voltage applied to the compensation control circuit. The compensation control circuit controls the light-emitting element to constantly emit light having a luminance based on a first voltage during a first interval of a light emission interval. The compensation control circuit controls the amount of current supplied to the light-emitting element based on a detection result of the optical sensor and the second voltage maintained in the first and second capacitors during a second interval and a third interval of the light emission interval, respectively.