Touch Circuit Pressure Sensing Voltage Dividing
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Solution Overview
Problem
Current touch display devices with pressure sensing functions require complex pressure sensing circuits, which can complicate the determination of touch pressure and position.
Innovation Solution
A touch circuit with a pressure sensing circuit including a pressure sensing resistor and an output circuit, where the pressure sensing circuit is coupled to a voltage dividing sub-circuit and an amplifying transistor, allowing for the determination of touch pressure and position with a simpler structure by varying resistance and voltage signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complex pressure sensing circuit is provided for pressure sensing function, then the pressure sensing capability is improved, but the circuit complexity increases
Solution Approach 1:
The patent combines the pressure sensing circuit with the touch scanning circuit by sharing common components (scan lines, output lines, and circuit structures). The pressure sensing resistor is integrated into the existing touch element structure, and the same scanning mechanism is used to read both touch position and pressure information, thereby reducing overall circuit complexity while maintaining pressure sensing capability
Solution Approach 2:
The touch element structure is designed to perform multiple functions: it can detect both touch position (through capacitance changes) and touch pressure (through resistance changes of the pressure sensing resistor). The scanning circuit universally serves both touch detection and pressure sensing functions, eliminating the need for separate dedicated pressure sensing circuits
2Measurement precision
If voltage dividing sub-circuit and amplifying transistor are added, then the determination accuracy of touch pressure is improved, but the circuit structure becomes more complex
Solution Approach 1:
The pressure sensing circuit is segmented into functional modules: the pressure sensing resistor that converts pressure to resistance changes, the voltage dividing sub-circuit that converts resistance changes to voltage changes, and the amplifying transistor that amplifies the voltage signal. This modular segmentation allows each component to perform its specific function efficiently while maintaining overall circuit simplicity through clear functional division
Solution Approach 2:
The circuit utilizes parameter changes in the pressure sensing resistor (resistance value changes with pressure) and transforms these changes through the voltage dividing sub-circuit (resistance to voltage conversion) and amplifying transistor (voltage amplification). This parameter transformation approach enables accurate pressure determination by converting subtle resistance changes into measurable voltage signals
3Device complexity
If the pressure sensing resistor is directly connected to voltage input terminals, then the circuit structure is simplified, but short circuits may occur
Solution Approach 1:
The voltage dividing sub-circuit acts as an intermediary between the voltage input terminal and the pressure sensing resistor. It includes a first resistor connected in series with the pressure sensing resistor, creating a voltage dividing network that prevents direct connection and potential short circuits while still allowing the pressure sensing resistor to function properly by measuring the voltage across it
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
Enables simultaneous determination of touch point position and pressure with a reduced circuit complexity, avoiding short circuits and improving accuracy through voltage dividing and amplification mechanisms.
Implementation Method 1
the pressure sensing circuit includes a pressure sensing resistor, a resistance value of the pressure sensing resistor varies as varying of the touch pressure
Data Source
AI summary
Provided is a touch circuit including first and second voltage input terminals, a pressure sensing circuit and an output circuit, the first voltage input terminal is configured to input a first voltage signal, the second voltage input terminal is configured to input a second voltage signal, the first voltage signal is different from the second voltage signal, an input terminal of the pressure sensing circuit is coupled to the first voltage input terminal, an output terminal of the pressure sensing circuit is coupled to an input terminal of the output circuit, a control terminal of the output circuit is configured to receive a control signal, and the output circuit is configured to control on/off state between the input terminal of the output circuit and the output terminal of the output circuit according to the control signal. A touch panel, a display panel and a display device are also provided.