Display Device Sensing Transistor Characteristics
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Solution Overview
Problem
Display devices, particularly organic light-emitting display devices, face challenges in maintaining uniform image quality due to inherent deviations in the characteristics of driving transistors across pixels, such as threshold voltages and mobility values, which affect the current supply to organic light-emitting diodes.
Innovation Solution
A display device and method that include a sensing unit to detect the characteristic information of driving transistors during specific sensing periods, allowing for the generation of compensatory data signals to ensure uniform current supply, thereby improving image quality by accounting for deviations in transistor characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If driving transistors are used to control current supply to organic light-emitting diodes, then the display device can operate with standard pixel structures, but deviations in transistor characteristics (threshold voltages and mobility values) cause non-uniform current supply and deteriorate image quality
Solution Approach 1:
The patent applies preliminary action by sensing the characteristic values of driving transistors before the actual display operation. During a sensing period, the system measures threshold voltages and mobility values of transistors, stores these values, and uses them to compensate for deviations during subsequent display operations. This preliminary measurement and storage of transistor characteristics enables uniform image quality without requiring perfectly matched transistors.
2Manufacturing precision
If sensing operations are performed to measure transistor characteristic values, then compensation for transistor deviations is possible, but additional time periods and control signals are required beyond standard display operation
Solution Approach 1:
The patent merges the sensing operations with the display operation timeline by integrating sensing periods into the overall display cycle. The sensing unit operates during dedicated sensing periods to measure transistor characteristics, while the control unit coordinates these measurements with the display refresh cycles. This integration allows the system to perform necessary sensing operations without completely separating them from display operations, optimizing the use of time resources.
3Adaptability or versatility
If multiple scan lines and control lines are used to supply signals to pixels, then comprehensive control of pixel operations is achieved, but the complexity of signal coordination increases
Solution Approach 1:
The patent segments the control functionality by separating scan lines (for row selection) from control lines (for pixel-level operations). Each pixel receives control signals through dedicated control lines that are selectively activated based on the sensing or display operation mode. This segmentation allows independent control of scanning and pixel operations, simplifying the coordination complexity despite having multiple lines.
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
The solution enables the display device to maintain uniform image quality by compensating for variations in driving transistor characteristics, ensuring consistent current supply to organic light-emitting diodes and enhancing overall image display performance.
Implementation Method 1
a sensing unit configured to sense the characteristic information of the driving transistors via the sensing lines during the sensing period
Implementation Method 2
each of the pixels has an organic light-emitting diode and a driving transistor. The driving transistor controls the amount of current that is supplied to the organic light-emitting diode
Implementation Method 3
the organic light-emitting diode generates light having predetermined luminance in response to the amount of current supplied from the driving transistor
Data Source
AI summary
A display device is configured to be driven in a period that is divided into a driving period and a sensing period. The display device includes pixels including driving transistors coupled to scan lines, data lines, and sensing lines, a scan driver configured to supply scan signals to the scan lines, a data driver configured to supply at least one of a reference voltage and data signals to the data lines, a sensing unit configured to sense the characteristic information via the sensing lines during the sensing period, control lines formed in parallel with the scan lines, a first switch coupled between an n-th scan line and an n-th control line, and a second switch coupled between the n-th control line and an (n+1)-th scan line and configured such that a turn-on period of the second switch does not overlap a turn-on period of the first switch.