Electroluminescent Display Pixel Sensing for Real-Time Threshold Compensation
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Solution Overview
Problem
Conventional electroluminescent display apparatuses face challenges in compensating for threshold voltage differences between pixels in real-time display driving, leading to luminance deviations and limitations in achieving desired images due to process deviations and degradation characteristics.
Innovation Solution
An electroluminescent display apparatus that includes a pixel with a driving element connected to a data line and a reference voltage line, utilizing a pixel driving circuit to apply sensing data voltages during vertical blank periods, detect source electrode voltages, calculate offset voltages, and adjust sensing data voltages based on these offsets to compensate for threshold voltage differences in real-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional threshold voltage sensing and compensation methods are used, then threshold voltage differences between pixels can be compensated, but real-time display driving cannot be performed due to the need for separate power off periods
Solution Approach 1:
The patent applies preliminary action by performing threshold voltage sensing and compensation during vertical blank periods before the next frame is displayed. The pixel driving circuit senses the threshold voltage of the driving element and calculates compensation values in advance, so that when the display frame is rendered, the compensation is already in place, enabling real-time display without requiring separate power off periods.
Solution Approach 2:
The patent implements dynamics by making the sensing data voltage adjustable and variable. The pixel driving circuit dynamically adjusts the sensing data voltage based on the detected source electrode voltage to accurately sense the threshold voltage of the driving element. This dynamic adjustment allows the system to adapt to different threshold voltage conditions while maintaining real-time display capability.
2Productivity
If threshold voltage compensation is performed during display operation, then real-time compensation is achieved, but additional circuit operations and voltage adjustments are required
Solution Approach 1:
The patent merges the threshold voltage sensing operation with the existing display driving operations. The pixel driving circuit uses the same data line and reference voltage line for both sensing and driving operations. The sensing operation is integrated into the vertical blank period of the display refresh cycle, combining multiple functions into a unified circuit operation sequence without requiring separate dedicated sensing circuits.
Solution Approach 2:
The pixel driving circuit is designed with multi-functionality to perform both display driving and threshold voltage sensing operations. The same circuit components, including the data line, reference voltage line, and pixel driving circuit elements, are used for both sensing the threshold voltage and driving the display, eliminating the need for separate dedicated sensing circuits and reducing overall system complexity.
Data Source
AI summary
An electroluminescent display apparatus may include a pixel including a driving element having a gate electrode connected to a data line and a source electrode connected to a reference voltage line and a pixel driving circuit applying a sensing data voltage to the gate electrode of the driving element through the data line, detecting a source electrode voltage of the driving element, shifted from a sensing reference voltage based on the sensing data voltage, through the reference voltage line to obtain a detection voltage, calculating an offset voltage based on the detection voltage, and lowering a level of the sensing data voltage based on the offset voltage, in a plurality of vertical blank periods.