OLED Degradation Sensing via Kickback Current Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for sensing OLED degradation in organic light emitting displays lack accuracy, leading to deviations in luminance and potential image sticking phenomena due to varying degradation rates across pixels.
Innovation Solution
An organic light emitting display system that divides pixels into groups connected to shared data and sensing lines, utilizing a gate driving circuit, data driving circuit, sensing circuit, and sensing value correction circuit to output first and second sensing values based on threshold voltage and kickback current, respectively, to calculate a final sensing value for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple sensing method is used to detect OLED degradation, then the device complexity is reduced, but the measurement precision of degradation sensing deteriorates
Solution Approach 1:
The sensing process is segmented into two distinct phases: a first sensing value obtained during a first time period and a second sensing value obtained during a second time period. This segmentation allows the system to separately measure different electrical characteristics (threshold voltage and kickback current) that together provide comprehensive degradation information, improving measurement precision without requiring a single complex sensing circuit
Solution Approach 2:
The patent introduces an intermediary calculation process that combines the first sensing value (threshold voltage) and the second sensing value (kickback current) to derive the final OLED degradation metric. This intermediary approach allows the system to use simple, separate measurements that are then processed together to achieve high measurement precision without complex individual sensing operations
2Device complexity
If kickback current is not corrected for, then the device complexity is reduced, but the measurement precision of threshold voltage sensing deteriorates
Solution Approach 1:
The patent extracts the kickback current component as a separate measurable quantity during the second time period. By isolating and measuring the kickback current independently from the threshold voltage measurement, the system can then remove this harmful interference from the final degradation calculation, significantly improving measurement precision
Solution Approach 2:
The patent converts the harmful kickback current effect into a useful measurement by deliberately measuring it during the second time period. What was originally a source of error (kickback current interfering with threshold voltage sensing) becomes a separate data point that, when combined with the first sensing value, provides more accurate degradation information
Data Source
AI summary
A display and degradation sensing method, includes a display panel having a plurality of pixels that each comprise an Organic Light Emitting Diode (OLED) and Thin Film Transistor (TFT). The pixels are divided into multiple pixel groups of two or more pixels, each connected to different data lines but to the same gate and sensing lines. A gate driving circuit supplies a scan control signal to the gate line. A data driving circuit selectively supplies turn-on driving data voltage and turn-off data voltage to the data lines in sync with the scan control signal; a sensing circuit outputs (i) a first sensing value based upon an OLED threshold voltage of a sensing pixel, and (ii) a second sensing value based upon a kickback current. A sensing value correction circuit determines a final sensing value for the OLED threshold voltage based on the first sensing value and the second sensing value.