Pixel Group Driving for OLED Luminance Uniformity
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Solution Overview
Problem
Conventional organic light emitting display devices face challenges in achieving uniform luminance across pixels due to deviations in element characteristics, particularly at low grayscale levels, where current flowing through each pixel is small, leading to inaccurate data compensation and low accuracy in removing low-grayscale stains without optical imaging techniques.
Innovation Solution
A method of driving a display panel by grouping adjacent pixels into pixel-groups and selectively controlling their luminance, where high grayscale levels are handled with normal driving and low grayscale levels are addressed through combination driving, which involves controlling only a portion of pixels to emit light at a higher luminance, effectively removing low-grayscale stains without data compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional data compensation using optical imaging technique is used, then luminance stains can be removed, but measurement precision is low for low-grayscale stains due to small current and camera device limitations
Solution Approach 1:
The patent merges multiple pixels into a pixel group and combines their currents to generate the luminance signal. By grouping m pixels and summing their currents, the system achieves sufficient signal strength even for low-grayscale displays, enabling accurate measurement without optical imaging techniques.
Solution Approach 2:
The patent replaces the optical imaging technique (camera-based measurement system) with an electrical current measurement system. Instead of using a camera to capture and analyze luminance, the system directly measures the sum of currents flowing through the pixel group, eliminating the limitations of optical measurement for low-grayscale stains.
2Illumination intensity
If all pixels are controlled to emit light at normal luminance, then high-grayscale levels are achieved, but low-grayscale stains cannot be effectively removed
Solution Approach 1:
The patent applies different driving strategies to different grayscale levels. For low-grayscale pixel groups, it uses combination driving where only selected pixels within the group emit light at higher luminance. For high-grayscale pixel groups, it uses normal driving where all pixels emit at standard luminance. This localized adaptation ensures uniform luminance across all grayscale levels.
Solution Approach 2:
The patent dynamically adjusts the driving mode based on the grayscale level of each pixel group. The system switches between normal driving and combination driving depending on whether the grayscale is above or below a reference threshold, enabling adaptive control that maintains luminance uniformity across varying grayscale conditions.
3Measurement precision
If combination driving is used for low-grayscale levels, then measurement precision improves, but device complexity increases due to pixel grouping and selective control
Solution Approach 1:
The patent segments the display panel into multiple pixel groups, where each group contains m adjacent pixels of the same color. This segmentation allows independent control and measurement of each group, simplifying the implementation of combination driving by treating each group as a manageable unit rather than controlling individual pixels across the entire display.
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
This approach ensures accurate control of pixel luminance across the display panel, enhancing image quality by effectively removing low-grayscale stains and providing high-quality images without relying on optical imaging techniques.
Implementation Method 1
each pixel may implement (or represent) a grayscale by controlling a current flowing through an organic light emitting element based on a data signal
Data Source
AI summary
A method of driving a display panel includes: grouping m adjacent pixels, which output same color light, into one pixel-group in the display panel, where m is an integer greater than or equal to two; determining whether a unit grayscale (UG) to be implemented by the pixel-group is greater than or equal to a determined reference grayscale (REFG) by analyzing respective data signals applied to the pixel-group; performing, in response to the UG being greater than or equal to the REFG, a normal driving that implements the UG by controlling all of the m adjacent pixels to emit light with first luminance corresponding to the respective data signals; and performing, in response to the UG being less than the REFG, a combination driving that implements the UG by controlling only a portion of the m adjacent pixels to emit light with second luminance that is greater than the first luminance.