Data Driving Circuit Compensation for OLED Transistor Deterioration
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Solution Overview
Problem
Organic light emitting display devices face image quality abnormalities due to deterioration of driving transistors, leading to inaccurate control of driving current and deviations in characteristic values between subpixels.
Innovation Solution
A circuit structure and driving method that compensates for changes in characteristic values of driving transistors by supplying a voltage including a loss compensation voltage, calculated based on the change value of the transistor's characteristic values, to prevent loss of compensation during the boosting period and improve accuracy of internal compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If internal compensation method is used to compensate for driving transistor deterioration, then compensation accuracy is improved, but compensation value is lost during boosting period
Solution Approach 1:
The patent applies preliminary action by calculating and storing the loss compensation voltage in advance based on the change value of driving transistor characteristic values. The data driving circuit pre-computes the compensation voltage that accounts for expected losses during the boosting period, and stores it in a storage unit before the actual compensation is needed. This ensures that when compensation is applied to the data voltage, the full compensation value is maintained without loss during the boosting period, thereby resolving the contradiction between achieving accurate compensation and preventing compensation value loss.
2Productivity
If driving time is increased to meet display demands, then productivity is improved, but driving transistor deterioration accelerates
Solution Approach 1:
The patent implements feedback by continuously monitoring the characteristic values of driving transistors (such as threshold voltage changes) and using this information to dynamically adjust the compensation voltage. The data driving circuit calculates the change value of transistor characteristics based on feedback from actual device performance, then computes and applies an appropriate loss compensation voltage. This closed-loop feedback mechanism enables the system to maintain reliable display performance over extended driving periods by continuously compensating for transistor deterioration, thus resolving the contradiction between improved productivity and maintained reliability.
Data Source
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AI summary
Embodiments of the present disclosure relate to a data driving circuit and a display device. In compensating for the change value of the characteristic value of the driving transistor disposed in the subpixel by an internal compensation method, by supplying a voltage including a loss compensation voltage calculated based on the change value of the characteristic value of the driving transistor to the subpixel, it is possible to prevent the compensation value reflected by the internal compensation from being lost in a boosting period after an internal compensation period and to improve the accuracy of the internal compensation. The data driving circuit comprises a sensing unit configured to detect a change value of a threshold voltage of a driving transistor included in at least one of a plurality of subpixels in an external sensing period; and a data voltage output unit configured to supply, in a display period, a data voltage obtained by adding a first voltage corresponding to a luminance of the subpixel and a second voltage smaller than the change value of the threshold voltage of the driving transistor to at least one subpixel of the plurality of subpixels.