Stylus Dual-Mode Detection Circuit for Capacitive and Resistive Sensors
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Solution Overview
Problem
The burden of designing separate circuits for capacitive and resistive sensors in styluses is significant due to their differing operational requirements, necessitating separate circuit boards.
Innovation Solution
A stylus with a detection circuit that can operate in both capacitive and resistive modes, using a common analog/digital circuit to convert analog signals from either sensor type, and switching between modes based on the installed sensor type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate circuits are designed for capacitive and resistive sensors, then each sensor type can be optimally driven, but the design burden and circuit complexity increase significantly
Solution Approach 1:
The detection circuit is designed to perform multiple functions by supporting both capacitive and resistive sensor types through a single unified circuit architecture. The circuit can selectively operate in different modes (first mode for capacitive sensors, second mode for resistive sensors) to accommodate different sensor types without requiring separate dedicated circuits for each sensor type.
Solution Approach 2:
The detection circuit incorporates dynamic switching capability between different operational modes. A mode selection mechanism allows the circuit to adaptively switch between capacitive detection mode and resistive detection mode based on which sensor type is installed, enabling the same hardware to dynamically adjust its operation characteristics.
2Ease of manufacture
If a single detection circuit handles both sensor types, then design burden is reduced, but circuit design becomes more challenging to accommodate both sensor requirements
Solution Approach 1:
The detection circuit is segmented into functionally independent modules: a capacitance detection circuit portion and a resistance detection circuit portion. Each module can be independently designed and optimized for its specific sensor type, while sharing common infrastructure such as the A/D conversion circuit. This modular segmentation reduces overall design complexity compared to creating entirely separate circuits.
Solution Approach 2:
The patent merges the capacitance detection circuit and resistance detection circuit into a single integrated detection circuit that shares common components, particularly the A/D conversion circuit. This combining approach reduces the total number of components and simplifies manufacturing while maintaining the ability to handle both sensor types through selective activation of appropriate circuit portions.
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 approach reduces the design burden by allowing a single circuit to handle both sensor types, optimizing for reduced power consumption and operational stability while maintaining accurate pen pressure data acquisition.
Implementation Method 1
a capacitive sensor in which a capacitance value changes according to applied force
Implementation Method 2
a resistive sensor in which a resistance value changes according to applied force
Data Source
AI summary
To reduce an increase in the burden of designing circuits used in a pen pressure sensor, provided is a stylus including a detection circuit that is connectable to a pen pressure sensor that, in operation, acquires pen pressure data of the stylus, the pen pressure sensor being a capacitive sensor in which a capacitance value changes according to applied force or a resistive sensor in which a resistance value changes according to applied force, the detection circuit can selectively operating in a first mode and a second mode, the detection circuit, in operation, acquiring the pen pressure data based on the capacitance value of the pen pressure sensor while the detection circuit operates in the first mode, and the detection circuit, in operation, acquiring the pen pressure data in reference to the resistance value of the pen pressure sensor while the detection circuit operates in the second mode.