Display Panel Pixel Parameter Measurement via Parasitic Subtraction
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Solution Overview
Problem
The challenge in accurately measuring small-scale parameters of semiconductive components in display panels, such as capacitance and electrical current, during testing, due to variations in fabrication processes, leads to low accuracy in simulation-based methods, necessitating direct measurement techniques.
Innovation Solution
A method involving measuring a first parameter of a display panel, disabling a pixel, measuring a second parameter after disabling, and deriving a third parameter by subtraction, which directly accounts for parasitic capacitances and improves measurement accuracy by excluding pixel contributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If simulation or computation is used to obtain parameters, then testing time is reduced, but measurement precision deteriorates due to fabrication variations
Solution Approach 1:
The measurement process is segmented into two distinct phases: first measuring the total capacitance with the pixel enabled, then measuring the parasitic capacitance with the pixel disabled. This segmentation allows separate characterization of pixel capacitance and parasitic effects, improving overall measurement precision while maintaining efficient testing throughput through automated sequential measurement.
Solution Approach 2:
The pixel is temporarily disabled (taken out of the measurement circuit) to measure only the parasitic capacitance of the probe card and circuitry. By extracting the pixel from the measurement path during the parasitic measurement phase, the method isolates and quantifies parasitic effects, enabling their subtraction from the total measurement to obtain accurate pixel parameters.
2Measurement precision
If direct measurement of individual parameters is performed, then measurement precision is improved, but device complexity increases due to additional measurement steps
Solution Approach 1:
The measurement system dynamically reconfigures the pixel state between two measurement modes: enabled state for total capacitance measurement and disabled state for parasitic capacitance measurement. This dynamic switching capability, implemented through automated control of the pixel transistor, allows the same measurement apparatus to perform both measurements without physical reconfiguration, managing complexity through software/control logic rather than hardware complexity.
Solution Approach 2:
The method uses feedback by measuring the parasitic capacitance and automatically subtracting it from the total capacitance measurement to derive the accurate pixel capacitance. This feedback mechanism (measuring parasitics and compensating for them in the calculation) improves precision while the automation of the subtraction process manages the complexity burden.
3Ease of manufacture
If parasitic capacitance is not accounted for, then measurement process is simplified, but reliability deteriorates due to inaccurate parameter derivation
Solution Approach 1:
The parasitic capacitance is measured in advance (preliminarily) with the pixel disabled, before the actual pixel capacitance measurement. This preliminary measurement of parasitic effects allows for their subsequent subtraction from the total measurement, ensuring accurate pixel parameter derivation while maintaining a systematic and reliable measurement process.
Solution Approach 2:
The disabled pixel acts as an intermediary state that allows measurement of the parasitic capacitance component. By creating this intermediate measurement condition (pixel disabled), the method separates the parasitic effects from the pixel effects, enabling accurate derivation of pixel parameters through mathematical subtraction while maintaining measurement reliability.
Data Source
AI summary
A method for testing and analyzing a display panel, comprising: providing a display panel including a circuitry and a pixel connected to the circuitry, wherein the pixel includes a capacitor, a transistor and an electrode electrically connected to the capacitor and the transistor; measuring a first parameter of the display panel; disabling the pixel; measuring a second parameter of the display panel; and deriving a third parameter of the pixel by subtracting the second parameter from the first parameter.