Pixel Sensing Circuit for Accurate Display Degradation Correction
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Solution Overview
Problem
Existing display devices inaccurately predict pixel degradation due to temperature estimation based on block calculations rather than individual pixel measurements, leading to ineffective grayscale correction.
Innovation Solution
Incorporating a pixel structure with transistors and a sensing channel to measure temperature and mobility of individual pixels, using a sensing line connected to a third node for accurate voltage variation analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If temperature prediction is performed through block calculation instead of individual pixel measurement, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The pixel is divided into functional sub-units: a sensing transistor (fourth transistor) dedicated to temperature sensing, separate from the drive transistors. This segmentation allows individual pixel temperature measurement without requiring complex external measurement equipment, resolving the contradiction by making the measurement system as simple as the pixel structure itself while achieving precise individual pixel temperature detection.
Solution Approach 2:
The sensing transistor shares the same structure and fabrication process with other drive transistors in the pixel, making it universal to the existing pixel design. The fourth transistor serves dual purposes: it is structurally identical to other drive transistors (maintaining manufacturing simplicity) while functioning specifically as a temperature sensor (achieving measurement precision).
2Measurement precision
If individual pixel temperature measurement is implemented, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The temperature sensing function is merged into the existing pixel structure by incorporating the fourth transistor within the pixel. This merging eliminates the need for separate external measurement equipment, reducing overall system complexity while achieving individual pixel temperature measurement. The sensing line connects the fourth transistor to a sensing channel, integrating measurement capability without adding external complexity.
Solution Approach 2:
The pixel structure itself provides the temperature sensing capability through the fourth transistor, which automatically detects temperature changes based on off-current variations. The pixel does not require external measurement equipment; it self-measures its temperature through the inherent temperature-dependent electrical characteristics of the fourth transistor, thereby achieving precise measurement without increasing device complexity.
3Ease of manufacture
If block-based temperature prediction is used, then ease of manufacture is improved, but reliability of grayscale correction deteriorates
Solution Approach 1:
The invention utilizes the temperature-dependent parameter change of the fourth transistor's off-current to detect temperature. By monitoring how the off-current changes with temperature, the system can determine pixel temperature and apply accurate grayscale correction. This parameter-based sensing approach maintains manufacturing simplicity (using standard transistor characteristics) while achieving reliable temperature-based grayscale correction.
Solution Approach 2:
The sensing channel measures the off-current of the fourth transistor and converts it to a voltage signal that reflects pixel temperature. This feedback mechanism provides real temperature information to the grayscale correction system, enabling accurate compensation for temperature-induced pixel degradation. The feedback loop ensures reliable grayscale correction based on actual pixel temperature rather than block-level predictions.
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
Enables precise temperature and mobility determination of pixels, allowing for improved grayscale correction and reduced luminance deviation by compensating for pixel degradation.
Implementation Method 1
The off-current of the fourth transistor changes at a greater rate than the off-current of the third transistor in response to temperature change
Data Source
AI summary
A display device includes a pixel and a sensing channel connected to the pixel through a sensing line. The pixel includes: a first transistor including a gate electrode connected to a first node, a first electrode connected to a first power line, and a second electrode connected to a second node; a second transistor including a gate electrode connected to a first scan line, a first electrode connected to a data line, and a second electrode connected to the first node; a third transistor including a gate electrode connected to a second scan line, a first electrode connected to the second node, and a second electrode connected to a third node; and a fourth transistor including a first electrode connected to the first power line and a second electrode connected to the third node. The sensing line is connected to the third node.