Pixel Circuit Segmentation for Low Gray-Scale Uniformity
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Solution Overview
Problem
In display technologies, particularly in OLED displays, achieving uniform gray-scale representation is challenging, especially in low gray-scale displays, where differences in film thicknesses of TFTs and organic light emitting layers lead to uneven display effects, resulting in a granular or mura effect.
Innovation Solution
A pixel circuit and driving method that partition the luminous region of a sub-pixel into two parts, each driven by a separate light emitting control circuit, allowing for different voltages to be applied to improve the driving current and reduce luminous area in low gray-scale displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single light emitting unit is used per sub-pixel, then the device structure is simple, but the display uniformity deteriorates in low gray-scale conditions
Solution Approach 1:
The sub-pixel is divided into two separate light emitting units (first and second light emitting units), each controlled by independent control circuits. This segmentation allows different voltage levels to be applied to different regions, enabling uniform gray-scale display across the entire sub-pixel area, particularly improving low gray-scale uniformity by compensating for voltage drops in specific regions
2Manufacturing precision
If different voltages are applied to different regions, then the display uniformity is improved, but the device complexity increases
Solution Approach 1:
Different voltage levels are applied to different regions of the sub-pixel through separate control circuits. The first light emitting control circuit controls the first light emitting unit while the second controls the second light emitting unit, allowing localized voltage adjustment to compensate for non-uniformities in film thickness and achieve uniform gray-scale display across the entire sub-pixel
3Manufacturing precision
If the luminous area is reduced in low gray-scale displays, then the brightness uniformity is improved, but the overall brightness decreases
Solution Approach 1:
The invention changes the voltage parameter applied to different light emitting units based on the desired gray-scale level. By independently controlling the voltage to the first and second light emitting units, the system can adjust brightness distribution to maintain uniformity while preserving overall brightness, avoiding the need to reduce total luminous area
Data Source
AI summary
A pixel circuit is provided and configured to drive a first light emitting unit and a second light emitting unit of a sub-pixel to emit light. The pixel circuit includes: an input circuit, a first light emitting control circuit, and a second light emitting control circuit. The input circuit is configured to write a data signal provided by a data signal line to a first node and store the data signal written into the first node, under controlling of a scanning signal provided by a scanning signal line. The first light emitting control circuit is configured to provide a driving current to a second node, under controlling of a first power supply signal provided by a first power supply line, the first node, and a light emitting control signal provided by a light emitting control signal line.