AMOLED Touch Display Circuit with Threshold Compensation
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Solution Overview
Problem
Current AMOLED displays face issues with uneven display luminance due to shifts in threshold voltage of the driving unit, which affects the operating current and overall display performance.
Innovation Solution
The integration of a photosensitive touch unit, a driving unit, and a threshold compensating unit into the AMOLED display circuit, where the threshold compensating unit adjusts the control voltage to maintain a stable operating current, independent of the threshold voltage shift, ensuring consistent luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional TFT-LCD control method is used, then stable voltage control is achieved, but current-driven OLED cannot maintain stable light emission
Solution Approach 1:
The patent changes the control parameter from voltage (TFT-LCD) to current (OLED), and introduces threshold voltage compensation as a key parameter adjustment mechanism to maintain stable light emission despite parameter variations
Solution Approach 2:
The patent implements a feedback mechanism through the threshold compensating unit that continuously adjusts the control voltage based on threshold voltage shifts, ensuring stable operating current and light emission
2Adaptability or versatility
If photosensitive touch control is integrated into AMOLED, then touch sensitivity and large-screen compatibility are improved, but threshold voltage shifts cause uneven luminance
Solution Approach 1:
The patent segments the pixel circuit into functional modules: photosensitive touch unit, driving unit, and threshold compensating unit, allowing independent optimization of touch sensitivity and luminance uniformity
Solution Approach 2:
The threshold compensating unit acts as an intermediary between the driving unit and the light-emitting unit, adjusting control voltage to compensate for threshold shifts and maintain uniform luminance
3Reliability
If threshold voltage compensation is implemented, then operating current stability is improved, but circuit complexity increases
Solution Approach 1:
The threshold compensating unit serves multiple functions: it compensates for threshold voltage shifts, stabilizes operating current, and maintains luminance uniformity, justifying the added circuit complexity through multi-functionality
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively stabilizes the operating current flowing through the light-emitting unit, preventing uneven luminance and ensuring normal operation of the OLED display by isolating it from threshold voltage fluctuations.
Implementation Method 1
the photosensitive touch unit includes: a first transistor, a second transistor, a third transistor and a first capacitor. A gate of the first transistor is connected with the first scanning signal terminal, and a first electrode of the first transistor is connected with the data line. A gate of the second transistor is connected with a first electrode of the second transistor, and the first electrode of the second transistor is connected with a second electrode of the first transistor. A first electrode of the first capacitor is connected with the gate of the second transistor, and a second electrode of the first capacitor is connected with a second electrode of the second transistor. A first electrode of the third transistor is connected with the second electrode of the second transistor, a gate of the third transistor is connected with the second scanning signal terminal, and a second electrode of the third transistor is connected with the signal detection line. The second transistor is a photosensitive transistor.
Data Source
AI summary
A touch display circuit and a display device are provided. The touch display circuit comprises a photosensitive touch unit (11), a driving unit (12), a threshold compensating unit (13) and a display unit (14). The photosensitive touch unit (11) generates a second detection signal under a control of a second scanning signal terminal (S2) when a first scanning signal terminal (S1) inputs a first detection signal. The threshold compensating unit (13) outputs a control voltage to a control terminal (d1) of the driving unit (12), outputs an operating voltage to an input terminal (d2) of the driving unit (12), and compensates a threshold voltage of the driving unit (12) by using the control voltage under control of a third scanning line signal terminal (S3), a fourth scanning line signal terminal (S4) and a data line (Data). The driving unit (12) outputs a driving current to the display unit (14) via an output terminal (d3) under control of the control voltage and the operating voltage. The display unit (14) is driven to emit light by the driving current under control of the fifth scanning signal terminal (S5). By using the touch display circuit, photosensitive in cell touch technology can be integrated into an AMOLED display.