Touch Substrate Voltage Divider Circuit for Illumination Stability
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Solution Overview
Problem
Current light sensing touch panels are overly sensitive to environmental factors due to a small working window, leading to incorrect determinations of touch events.
Innovation Solution
Incorporating a voltage divider circuit on a substrate, electrically coupled with a light sensing circuit, which outputs a first voltage based on the degree of illumination or capacitance change, thereby increasing the working window of the light sensing circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light sensing circuit is used to detect touch events by leakage current, then touch detection capability is provided, but the working window is too small causing excessive sensitivity to environmental factors
Solution Approach 1:
A voltage divider circuit is introduced as an intermediary component between the light sensing circuit and the scan lines. The voltage divider circuit includes a first transistor whose gate is connected to the scan line and whose drain is connected to the light sensing circuit. This intermediary circuit processes the signal from the light sensing circuit before it reaches the scan line, thereby expanding the working window and reducing excessive sensitivity to environmental factors while maintaining touch detection capability.
2Difficulty of detecting and measuring
If the working window of the light sensing circuit is small, then the circuit can detect touch events, but it becomes too sensitive to voltage and temperature variations
Solution Approach 1:
The voltage divider circuit serves as a mediator that buffers the light sensing circuit from direct connection to the scan line. By introducing this intermediate stage with controlled impedance and signal conditioning, the circuit maintains its ability to detect touch events while reducing the direct impact of voltage and temperature variations on the detection accuracy.
3Device complexity
If the light sensing circuit directly connects to scan lines, then circuit structure is simple, but the working window is insufficient for accurate touch determination
Solution Approach 1:
The circuit is segmented into distinct functional blocks: the light sensing circuit, the voltage divider circuit, and the scan line interface. This segmentation allows each component to perform its specific function optimally - the light sensing circuit detects touch events, the voltage divider circuit conditions the signal and expands the working window, and the scan line provides the control signal. This modular approach improves measurement precision while keeping each individual component relatively simple.
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 configuration allows for more accurate determination of touch events by providing a larger distinguishable voltage difference between on-light and off-light states, reducing false positives from environmental factors.
Implementation Method 1
the light sensing circuit is configured to detect a touch event by the degree of leakage current, which is generated and corresponding to the illumination thereon
Implementation Method 2
The voltage divider circuit has an output terminal and is configured to output a first voltage to the light sensing circuit through the output terminal thereof according to a degree of illumination thereon or a degree of capacitance change
Data Source
AI summary
A substrate with touch function includes a plurality of scan lines and at least a touch device disposed thereon. The touch device includes at least a power line, at least a readout line, a light sensing circuit and a voltage divider circuit. The power line and the readout line are disposed on the substrate. The light sensing circuit is electrically coupled to a (N+1)th of the power lines, an Nth of the scan lines and an Nth of the readout lines, wherein N is an integer. The voltage divider circuit has an output terminal and is configured to output a first voltage to the light sensing circuit through the output terminal thereof according to a degree of illumination thereon or a degree of capacitance change. A display using the aforementioned substrate is also provided.