Display Device Sensing Transistor for Deterioration Detection
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Solution Overview
Problem
Existing display devices face challenges in accurately determining the deterioration of light-emitting elements, particularly due to variations in luminance and kickback voltages, which affect the reliability of compensation methods.
Innovation Solution
A display device and method that utilize a sensor to sense deterioration information by controlling the voltage applied to the light-emitting element, using a scan driver to supply scan signals and a data driver to supply data signals, while a sensing transistor and switching transistor are turned on to accurately measure the voltage, thereby isolating the impact of kickback voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If data accumulation method is used to determine deterioration, then deterioration information can be obtained, but measurement precision is insufficient due to luminance variations and kickback voltages
Solution Approach 1:
The patent extracts the voltage sensing function from the normal display operation by introducing a dedicated sensing transistor and sensing line. This separates the deterioration measurement process from the regular pixel operation, allowing accurate voltage measurement without interference from kickback voltages during switching operations.
Solution Approach 2:
The patent introduces a sensing transistor as an intermediary component between the light-emitting element and the sensing line. This intermediary allows the sensor to measure the voltage applied to the light-emitting element without directly interfering with the pixel's normal operation, isolating the measurement from harmful kickback effects.
2Measurement precision
If sensor is added to sense voltage, then deterioration determination accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the sensing transistor and sensing capacitor within the existing pixel structure, combining multiple functions (switching, sensing, and signal transmission) into a unified integrated design. This reduces the need for separate external components and minimizes overall device complexity.
Solution Approach 2:
The sensing transistor serves multiple functions: it acts as a switch to control the sensing operation, a sensor to detect voltage changes, and a signal transmission element to convey deterioration information to the sensor. This multi-functionality reduces the need for additional dedicated components.
3Ease of operation
If kickback voltage effects are present during sensing, then measurement is simpler, but measurement precision deteriorates
Solution Approach 1:
The patent performs preliminary initialization of the sensing capacitor to a known voltage state before the actual sensing operation. This preliminary action establishes a stable baseline, ensuring that subsequent voltage measurements are accurate and not affected by residual charges or kickback voltages from previous operations.
Solution Approach 2:
The patent uses the sensing capacitor to cushion or buffer against voltage fluctuations and kickback effects during the sensing operation. By pre-charging or pre-discharging the capacitor to appropriate levels, the system protects the measurement process from harmful voltage transients that would otherwise degrade measurement precision.
Data Source
AI summary
A display device includes a scan driver to supply scan signals to first and second scan lines, a data driver to supply a data signal to data lines, a sensor connected to sensing lines, and pixels including a light-emitting element, a driving transistor to control an amount of current supplied to the light-emitting element in response to a voltage of a first node, a switching transistor between a j-th data line and the first node, and including a gate electrode coupled to an i-th first scan line, and a sensing transistor coupled between a second node, which is between the light-emitting element and the driving transistor, and a k-th sensing line, and including a gate electrode coupled to an i-th second scan line, and wherein the sensor is to sense deterioration information of the light-emitting element in a state in which the switching and sensing transistors are turned on.