Display Apparatus Pixel Compensation for Luminance Uniformity
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Solution Overview
Problem
The quality of images in display apparatuses is affected by variations in voltage-current characteristics of light emitting elements, leading to luminance unevenness and image degradation due to manufacturing variations and time-dependent degradation, and existing sensing methods cause contrast degradation and line defects during measurement.
Innovation Solution
A display apparatus with a control unit that manages light emission and sensing operations for each pixel circuit, compensating display data by subtracting the sensing light emission amount from the display light emission amount to maintain consistent light emission across pixel circuits, thereby preventing image degradation during sensing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensing operation is performed on pixel circuit to measure light emitting element characteristics, then measurement precision is improved, but image quality deteriorates due to contrast degradation and line defects
Solution Approach 1:
The patent divides the operation into distinct sensing interval and display interval, separating the sensing operation from the normal display operation. During the sensing interval, only the sensing operation is performed on selected pixel circuits, while during the display interval, normal image display is performed on all pixel circuits. This temporal segmentation prevents sensing operations from degrading display image quality.
Solution Approach 2:
The patent implements periodic sensing operations at specific intervals rather than continuous sensing. The control unit selectively performs sensing operations on target pixel circuits during designated sensing intervals, allowing the display apparatus to periodically measure light emitting element characteristics without continuously degrading image quality. This periodic approach balances measurement needs with display quality maintenance.
2Manufacturing precision
If sensing operation is performed on target pixel circuit, then manufacturing precision monitoring is improved, but luminance unevenness occurs due to light emission during sensing
Solution Approach 1:
The patent extracts the sensing operation from the normal display operation by dedicating specific sensing intervals for measurement activities. During these intervals, selected pixel circuits are isolated for sensing purposes, and their sensing light emission amounts are separately measured and compensated. This extraction allows manufacturing precision monitoring without affecting overall luminance uniformity of the display.
Solution Approach 2:
The patent implements a feedback mechanism where the sensing light emission amount measured during sensing intervals is used to compensate display data in subsequent display intervals. The compensation unit adjusts display data based on the measured sensing light emission amounts, ensuring that any luminance variations caused by sensing operations are corrected in the displayed image, thereby maintaining luminance uniformity.
3Reliability
If compensation is applied to maintain consistent light emission, then image quality is improved, but device complexity increases due to additional control mechanisms
Solution Approach 1:
The control unit and compensation unit are designed to perform multiple functions: they control both normal display operations and sensing operations, manage timing intervals, select target pixel circuits for sensing, measure sensing light emission amounts, and generate compensated display data. By making these control units multi-functional, the patent avoids adding separate dedicated circuits for each function, thereby limiting the increase in device complexity while achieving image quality consistency.
Data Source
AI summary
A display apparatus includes a display unit, a control unit, and a compensation unit. The compensation unit may compensate the display data when a sensing operation is performed on a target pixel circuit, the compensation unit compensating display data by setting a light emission amount of light emitting element of a target pixel circuit to be an amount obtained by subtracting a sensing light emission amount, which is a light emission amount of the light emitting element of the target pixel circuit during a sensing interval, from a display light emission amount, which is a light emission amount of the light emitting element of the target pixel circuit before the compensation.