Touch Sensor Pulse-Width Calibration for Stable Contact Detection
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Solution Overview
Problem
Conventional touch sensors face challenges in precisely sensing touch object contact and are prone to malfunctions due to varying operating conditions such as power supply voltage and temperature, especially when touch sensitivity is low or electrostatic capacitance is small, with no calibration element to adjust for these changes.
Innovation Solution
A touch sensor system that includes a pulse signal generator, transmitter, detector, and controller to adjust pulse width based on operating conditions, using a resistor or variable resistor to inhibit pulse signal transmission when the touch object is in contact, allowing precise contact detection and calibration to prevent malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the touch sensor uses a conventional delay time comparison method, then the touch sensing function is implemented, but the sensing precision deteriorates when the touch object has very small electrostatic capacitance
Solution Approach 1:
The patent changes the measurement parameter from delay time difference to pulse width. By measuring the width of the pulse signal instead of comparing delay times, the system can accurately detect touch objects with very small electrostatic capacitance values, resolving the measurement precision issue while maintaining sensing reliability
2Device complexity
If the touch sensor operates without calibration elements, then the device complexity is reduced, but the reliability deteriorates due to variations in operating conditions such as power supply voltage and temperature
Solution Approach 1:
The patent implements self-calibration functionality where the touch sensor automatically compensates for variations in operating conditions. The system performs self-adjustment based on detected parameters, eliminating the need for external calibration elements while maintaining high reliability across different power supply voltages and temperatures
3Manufacturing precision
If the touch sensor uses fixed impedance circuit devices, then the manufacturing precision is improved, but the reliability deteriorates due to impedance variations with operating conditions
Solution Approach 1:
The patent introduces dynamic adjustment capabilities to the circuit devices, allowing impedance to vary adaptively with operating conditions. This dynamic behavior compensates for environmental variations while maintaining manufacturing precision, as the circuit automatically adjusts its characteristics based on real-time operating parameters
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
Enhances the reliability of touch sensing by ensuring accurate detection of touch object contact and preventing malfunctions due to changing operating conditions, while reducing noise influence in capacitance measurement circuits.
Implementation Method 1
sensing whether or not a touch object is in contact with the touch sensor by varying a difference in delay time between a touch signal and a reference signal using the electrostatic capacitance of the touch object
Implementation Method 2
a pulse signal transmitter for transmitting the pulse signal when a touch object is out of contact with a touch pad and stopping transmitting the pulse signal when the touch object is in contact with the touch pad
Data Source
AI summary
Provided are a touch sensor and a method of operating the same. The touch sensor includes: a pulse signal generator for generating a pulse signal of which pulse width is calibrated in response to a control code; a pulse signal transmitter for transmitting the pulse signal when a touch object is out of contact with a touch pad and stopping transmitting the pulse signal when the touch object is in contact with the touch pad; a pulse signal detector for detecting the pulse signal transmitted through the pulse signal transmitter; and a controller recognizing a non-contact state and adjusting the control code to calibrate the pulse width of the pulse signal when the pulse signal detector detects the pulse signal. In the above-described configuration, the contact of the touch object with the touch pad can be sensed more precisely, and the occurrence of a malfunction in the touch sensor due to changed operating conditions can be prevented. As a result, the operating reliability of the touch sensor can be enhanced.