Display Panel Reference-Line Sensing and Compensation for Luminance Uniformity
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Solution Overview
Problem
Large display apparatuses experience voltage drops at both ends due to differences in wiring length from the control printed circuit board, leading to luminance differences and image quality defects such as vertical stripe stains.
Innovation Solution
A display apparatus with a configuration that includes data lines connected to driving transistors, reference lines connected to sensing transistors, and a timing controller that senses and compensates for reference voltage deviations independently of driving characteristics, using analog-to-digital converters to adjust voltages and improve luminance uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display apparatus is enlarged in size, then the display area is increased, but voltage drop occurs and luminance uniformity deteriorates
Solution Approach 1:
The patent divides the display panel into multiple sensing regions corresponding to different reference lines (first reference line, second reference line, etc.). Each region is independently sensed and compensated, allowing localized correction of voltage drop effects across the enlarged display area, thereby maintaining luminance uniformity.
Solution Approach 2:
The patent applies different compensation values to different regions of the display panel based on their specific voltage drop characteristics. Each subpixel group associated with a particular reference line receives tailored compensation, ensuring that local luminance variations are corrected according to the actual electrical conditions in each region.
2Length of stationary object
If wiring length increases to cover larger display area, then display size is increased, but voltage drop and image quality defects worsen
Solution Approach 1:
The patent implements a feedback mechanism where the sensing transistor senses the actual reference voltage at each reference line, and this sensed information is used to calculate and apply compensation values. This closed-loop feedback system continuously corrects for voltage drop effects, maintaining image quality reliability despite increased wiring lengths in enlarged displays.
Solution Approach 2:
The patent dynamically adjusts the reference voltage parameter by applying compensation values to each reference line based on sensed deviations. This parameter change approach allows the system to adapt to varying voltage conditions across different wiring lengths, preventing image quality defects while maintaining the enlarged display configuration.
3Manufacturing precision
If reference voltage is supplied to all reference lines, then voltage uniformity is improved, but power consumption increases
Solution Approach 1:
Instead of uniformly adjusting all reference lines, the patent applies compensation only to specific reference lines where voltage deviations are detected. Each reference line receives localized adjustment based on its individual sensing results, achieving voltage uniformity where needed while avoiding unnecessary power consumption in regions that already have adequate voltage levels.
Solution Approach 2:
The patent selectively modifies the reference voltage parameter only for reference lines that exhibit deviations from the target voltage level. By changing parameters only where necessary rather than globally, the system achieves voltage uniformity improvement while minimizing the additional power consumption that would result from blanket adjustments across all reference lines.
Data Source
AI summary
Disclosed is a display apparatus comprising a display panel including data lines connected to a driving transistor of each of subpixels for displaying an image, and reference lines connected to a sensing transistor of each of the subpixels, a data driver configured to supply a data voltage to the data lines and supplying a reference voltage to the reference lines, and a timing controller configured to control the data driver, sense a reference voltage deviation of each of the reference lines changed independent from a driving characteristic of a subpixel by supplying the reference voltage to the reference lines without supplying the data voltage to the data lines, and compensate for the reference voltage deviation.