Reference Voltage Line Defect Detection in Display Data Driving Circuits
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Solution Overview
Problem
In organic light-emitting displays, luminance deviations among subpixels occur due to changes in characteristic values of driving transistors over time, and errors in sensing and compensating these values are exacerbated by defects in the reference voltage line, such as moisture penetration or impurities, leading to poor image quality.
Innovation Solution
A display device and method that includes a data driving circuit capable of detecting defects in the reference voltage line by varying voltage detecting paths, determining whether the line is abnormal, and compensating for characteristic values based on this determination, thereby reducing errors in sensing and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single voltage detecting path is used for sensing reference voltage, then the device complexity is reduced, but measurement precision deteriorates due to inability to detect line defects
Solution Approach 1:
The voltage detecting operation is segmented into multiple detecting periods (first detecting period and second detecting period) with different detecting paths. The first detecting path senses voltage during the first detecting period, while the second detecting path senses voltage during the second detecting period. This segmentation allows the system to compare results from different paths to identify line defects, thereby improving measurement precision without requiring a permanently complex detecting structure.
2Reliability
If defect detection operation is performed on reference voltage line, then reliability is improved, but loss of time increases due to additional detection periods
Solution Approach 1:
The defect detection is performed as a preliminary action before the main characteristic value sensing operation. By executing the first and second detecting periods to identify reference voltage line defects beforehand, the system ensures reliable subsequent sensing operations. This preliminary detection prevents time loss during actual sensing by avoiding re-detections due to undetected defects.
3Measurement precision
If multiple detecting paths are used for voltage sensing, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The detecting circuit is designed with multi-functionality to serve both defect detection and normal sensing operations. The same sensing circuitry is used in both the first detecting period and the second detecting period, just with different detecting paths activated at different times. This universal design allows multiple detecting paths to be utilized without proportionally increasing device complexity, as the underlying hardware remains shared rather than duplicated.
Data Source
AI summary
A display device includes a display panel, a data driving circuit, and a timing controller, wherein the display panel includes a plurality of gate lines to which a scan signal is applied, a plurality of data lines to which a data voltage is applied, a plurality of reference voltage lines to which a reference voltage is applied, and a plurality of subpixels, wherein the data driving circuit senses a voltage on one reference voltage line selected from the plurality of reference voltage lines in a first detecting period and a second detecting period having different voltage detecting paths, and wherein the timing controller controls the data driving circuit, and determining whether or not the reference voltage line is abnormal using a sensing voltage detected from the reference voltage line.