OLED Display Compensation for Mobility and Threshold Voltage
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Solution Overview
Problem
Existing active matrix organic light emitting displays face challenges in uniform image quality due to non-uniform electrical characteristics of driving TFTs, requiring separate sensing methods for threshold voltage and mobility, which are time-consuming and memory-intensive, and cannot update compensation values in real-time, especially for threshold voltage changes.
Innovation Solution
Implementing a fast mode sensing method to simultaneously determine the change amounts of both mobility and threshold voltage using a single sensing process, allowing for compensation during vertical blank periods and reducing the need for additional memory by integrating threshold voltage and mobility compensation into a single process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate sensing methods are used for threshold voltage and mobility, then measurement precision is improved, but sensing time increases and productivity decreases
Solution Approach 1:
The patent merges the previously separate threshold voltage sensing method and mobility sensing method into a single integrated sensing process. By applying a sequence of voltages (first voltage, second voltage, third voltage) to the driving TFT, the system simultaneously obtains both threshold voltage change amount and mobility change amount from the same sensing operation, eliminating the need for separate sensing operations and reducing total sensing time.
Solution Approach 2:
The sensing method becomes universal by using a single sensing process that serves multiple functions: it measures both threshold voltage characteristics and mobility characteristics. The method applies different voltage conditions within the same sensing framework to extract multiple parameters, making the sensing operation multi-functional rather than requiring specialized separate procedures for each parameter.
2Measurement precision
If separate sensing methods are used for threshold voltage and mobility, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines the sensing circuits and control logic for threshold voltage and mobility into a unified sensing system. The same sensing circuitry processes multiple voltage conditions and extracts both threshold voltage and mobility information, reducing the need for duplicate sensing components and simplifying the overall device architecture.
Solution Approach 2:
The sensing system achieves multi-functionality by using a single integrated sensing mechanism that can measure both threshold voltage and mobility parameters. This universal approach eliminates the need for separate dedicated sensing systems for each parameter, reducing device complexity while maintaining measurement precision for both quantities.
3Measurement precision
If slow mode sensing method is used for threshold voltage, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The patent merges the time-consuming threshold voltage sensing operation with the mobility sensing operation into a single integrated process. By doing so, the system maintains the precision of threshold voltage measurement while avoiding the cumulative time penalty of separate sensing operations, thereby preserving higher productivity and enabling timely image display refreshes.
Solution Approach 2:
The sensing method performs preliminary voltage application and stabilization within the integrated sensing process, allowing threshold voltage measurement to be completed more efficiently. By structuring the voltage application sequence optimally, the system achieves precise threshold voltage measurement without requiring extended sensing periods that would reduce productivity.
4Measurement precision
If separate memory storage is used for offset value and gain value, then measurement precision is improved, but loss of substance increases
Solution Approach 1:
The patent merges the storage requirements for offset values and gain values into a unified memory structure or storage mechanism. By coordinating the sensing and storage operations, the system maintains precise compensation parameters while reducing the total memory resources required, as the same storage infrastructure serves both parameter types rather than requiring separate dedicated memory areas.
Data Source
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AI summary
Provided is an organic light emitting diode (OLED) display device including a plurality of pixels (P) to display images, each of the pixels (P) including an OLED, a driving transistor (DT) connected to the OLED, and a switching transistor (ST1, ST2) configured to supply data signals to the OLED, the device including: a sensing unit (30) configured to sense a change amount of a mobility of the driving transistor (DT); a compensation value calculator (41) configured to obtain a change amount of a threshold voltage of the driving transistor (DT) based on the sensed change amount of the mobility; and a data compensator (50) configured to adjust the data signals based on the sensed change amount of mobility and the obtained change amount of the threshold voltage.