Display Driving Transistor Threshold Voltage Sensing
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Solution Overview
Problem
Existing display apparatuses face challenges in sensing and compensating for the degradation of driving transistors, particularly in reducing the time required for sensing the threshold voltage of driving transistors, which affects image quality, especially after a long period of non-use.
Innovation Solution
A method and apparatus that perform a fourth sensing of the threshold voltage of driving transistors after the display apparatus is powered on but before an image is displayed, allowing for high-speed sensing by sampling before the threshold voltage saturates, and optionally using a lookup table to improve accuracy and selectively omitting sensing based on user input or non-use time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the threshold voltage of the driving transistor is sensed after the display apparatus is powered off (third sensing), then the sensing accuracy is improved, but the sensing time is excessively long due to waiting for threshold voltage saturation
Solution Approach 1:
The patent performs a fourth sensing of the threshold voltage after the display apparatus is powered on but before an image is displayed. This preliminary sensing action captures the threshold voltage at an earlier time point when it has not yet saturated, thereby reducing the sensing time while still providing usable compensation data before actual display operation begins.
Solution Approach 2:
The patent changes the timing parameter of the threshold voltage sensing operation. Instead of waiting for the threshold voltage to saturate (as in the third sensing), the fourth sensing measures the threshold voltage at a different time point - specifically, after power-on but before image display - when the voltage has not reached saturation, thus achieving faster sensing.
2Manufacturing precision
If multiple sensing operations (first, second, third, and fourth sensing) are performed to compensate for both mobility and threshold voltage degradation, then the image quality is improved, but the overall sensing time and processing complexity increase
Solution Approach 1:
The patent divides the sensing process into four distinct sensing operations targeting different parameters at different times: first sensing (mobility after power-on), second sensing (mobility after image display), third sensing (threshold voltage after power-off), and fourth sensing (threshold voltage after power-on but before image display). Each sensing operation focuses on a specific parameter at an optimal time point, allowing comprehensive compensation without requiring all parameters to be measured simultaneously.
Solution Approach 2:
The fourth sensing performs threshold voltage measurement preliminarily before image display begins. This preliminary action ensures that threshold voltage compensation is ready in advance, allowing the actual image display to proceed without waiting for lengthy threshold voltage saturation periods, thus improving overall system efficiency.
3Speed
If the fourth sensing is performed after power-on but before image display, then the sensing speed is improved, but the sensing must be completed within a very short time window
Solution Approach 1:
The fourth sensing rushes through the threshold voltage measurement process by performing it during the brief period after power-on but before image display. This approach skips the traditional waiting period for threshold voltage saturation and completes the sensing operation within the available time window, achieving high sensing speed.
Data Source
AI summary
A display apparatus and a sensing method for compensation is disclosed, and more particularly, a method for sensing and compensating for degradation of a driving transistor of a display apparatus and a display apparatus performing the method is disclosed. A method for sensing a threshold voltage of a driving transistor after a display apparatus is powered on and before an image is displayed, and a display apparatus performing the sensing method are provided. Accordingly, it is possible to reduce the sensing time in sensing the threshold voltage of the driving transistor.