In-Cell Touch LCD Driving Voltage Intermittent Control
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Solution Overview
Problem
In-cell touch panel type liquid crystal displays face challenges in accurately detecting touch positions due to relative differences in light currents, leading to unreliable touch sensor circuits, especially in varying light environments and prolonged usage, which can result in false touch detections.
Innovation Solution
A liquid crystal display with a transparent conductive layer and an insulating layer that generates touch or non-touch sensing signals based on surface charge changes, and a driving voltage supply circuit that only provides high potential voltage for light sensing when the touch sensor circuit indicates a touch, thereby improving accuracy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the touch sensor circuit continuously operates with high potential voltage for light sensing, then the touch detection accuracy is maintained, but the sensor TFT degrades faster reducing reliability
Solution Approach 1:
The touch sensor circuit operates intermittently rather than continuously. The driving voltage supply circuit applies high potential voltage only during necessary sensing periods, allowing the sensor TFT to rest during non-touch periods. This periodic operation reduces cumulative degradation while maintaining touch detection accuracy when needed.
2Measurement precision
If the touch sensor circuit operates continuously to detect touch positions, then touch detection accuracy is maintained, but energy consumption increases and sensor TFT degrades
Solution Approach 1:
The system performs touch sensing periodically rather than continuously. The driving voltage supply circuit supplies high potential voltage to the touch sensor circuit only during specific time intervals when touch detection is required, reducing energy consumption while maintaining detection accuracy during active periods.
3Adaptability or versatility
If the driving voltage is continuously applied to the touch sensor circuit, then the light sensing operation is always available, but the sensor TFT degradation accelerates
Solution Approach 1:
The driving voltage supply circuit provides high potential voltage intermittently rather than continuously. This periodic voltage application maintains light sensing capability during active periods while allowing the sensor TFT to recover during inactive periods, improving overall reliability without completely sacrificing adaptability.
Solution Approach 2:
The system dynamically adjusts the operating state of the touch sensor circuit based on touch detection needs. The driving voltage supply circuit transitions the sensor circuit between active (high potential voltage applied) and inactive (voltage reduced or removed) states, optimizing the balance between sensing availability and component reliability.
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 accurately detects touch positions and reduces sensor TFT degradation by intermittently applying driving voltage only when touched, enhancing the reliability and lifespan of the touch sensor circuit.
Implementation Method 1
a sensing circuit to generate a touch or non-touch sensing signal based on changes in the amount of surface charge of the transparent conductive layer depending on whether or not the insulating layer is touched
Data Source
AI summary
A liquid crystal display includes a transparent conductive layer on an first substrate of a liquid crystal display panel transmitting display light, an insulating layer on the transparent conductive layer, a sensing circuit to generate a touch or non-touch sensing signal based on changes in the amount of surface charge of the transparent conductive layer depending on whether or not the insulating layer is touched, and a driving voltage supply circuit to generate a driving voltage of a high potential for a light sensing operation of a touch sensor circuit only when the touch or non-touch sensing signal indicates that the insulating layer is touched.