OLED Pixel Degradation Sensing via Dynamic Reference Voltage
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Solution Overview
Problem
Existing organic light emitting display devices face challenges in accurately determining pixel degradation due to varying operation points and requiring initialization time for reference voltage application, which increases measurement time and reduces accuracy.
Innovation Solution
An organic light emitting display device and method that generate a reference voltage based on a data signal provided to each pixel, allowing for real-time measurement of pixel characteristics by considering the actual operation point, using a sensing unit with a reference voltage generator, integrator, and converters to generate sensing data without initialization, thereby reducing sensing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference voltage is provided to a pixel to measure current, then measurement can be performed, but pixel initialization time is required which increases sensing time
Solution Approach 1:
The patent applies preliminary action by pre-storing multiple reference voltages with different operation voltage levels in a reference voltage generator before measurement is needed. When measurement is required, the appropriate reference voltage is immediately selected and applied without requiring pixel initialization time, thus reducing sensing time while maintaining measurement capability.
2Device complexity
If only one reference voltage is provided to a pixel, then measurement is simplified, but accurate determination of pixel degradation cannot be achieved due to varying operation points
Solution Approach 1:
The patent applies local quality by providing different reference voltages with different operation voltage levels tailored to match the specific operation point of each pixel or different pixel groups. This allows accurate degradation detection for pixels operating at different points while maintaining a relatively simple measurement system structure through systematic voltage selection and control.
Solution Approach 2:
The patent applies parameter changes by varying the operation voltage level of the reference voltage applied to the pixel based on the pixel's operation point. By changing the voltage parameter dynamically or selectively, the measurement system can accurately detect degradation across pixels with different operation points without requiring complex measurement procedures.
3Productivity
If the operation voltage level of reference voltage does not match the pixel operation point, then measurement is faster, but accurate degradation determination cannot be made
Solution Approach 1:
The patent applies dynamics by making the reference voltage selection dynamic rather than static. The reference voltage generator dynamically selects and switches between multiple reference voltages with different operation voltage levels based on the specific pixel's operation point, enabling both fast measurement (by immediate voltage application) and accurate degradation detection (by matching the operation voltage level).
Data Source
AI summary
An organic light emitting display device includes a display panel including a pixel at an intersection of a data line, a feedback line, and a scan line; a data driver configured to provide a data signal to the pixel through the data line; and a sensing unit configured to generate a reference voltage based on the data signal, to generate first sensing data based on a sensing current that flows through the feedback line in response to the reference voltage, and to generate second sensing data by digital-converting the reference voltage.