RF Antenna Touch Sensing Using Self-Capacitance Switching
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Solution Overview
Problem
Existing electronic devices face challenges in accurately determining touch inputs due to calibration errors in capacitive sensors, increased manufacturing time, and power consumption issues, particularly in wearable devices where tattoos can interfere with blood flow measurements and mounting efficiency is compromised by connector additions.
Innovation Solution
An electronic device with a housing containing a Radio Frequency (RF) communication circuit, an antenna radiator, a conductive member, a switching circuit, and a processor that controls the connection between the sensor and the conductive member to determine touch states, using self-capacitance measurements to improve recognition rates and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If threshold capacitance is set through calibration of capacitive sensor, then touch detection accuracy is improved, but manufacturing time increases and productivity deteriorates
Solution Approach 1:
The patent extracts the calibration function from the manufacturing process by using the conductor's own body capacitance as the reference threshold. Instead of requiring external calibration equipment and procedures, the system automatically determines touch thresholds by measuring capacitance changes when the conductor's body contacts the sensing pad, thereby eliminating calibration steps and improving productivity while maintaining detection accuracy.
Solution Approach 2:
The conductor's body capacitance serves as the self-reference for calibration. The system uses the conductor's own physiological characteristics (body capacitance) to automatically establish detection thresholds without requiring external calibration equipment or operator intervention, enabling self-calibration that improves both accuracy and manufacturing efficiency.
2Measurement precision
If LED is turned on to raise IR sensor recognition accuracy, then detection accuracy is improved, but current consumption increases
Solution Approach 1:
The LED operates in periodic pulsing mode rather than continuous operation. The control unit activates the LED only during specific measurement intervals when IR sensor data collection is required, then deactivates it. This periodic activation maintains sufficient light intensity for accurate blood flow detection while dramatically reducing overall current consumption compared to continuous LED operation.
3Reliability
If connector or contact terminal is added to electrically connect sensing pad and touch sensor, then electrical connection is improved, but mounting efficiency deteriorates
Solution Approach 1:
The patent merges the electrical connection function directly into the housing structure by forming a conductive member that is integrally coupled to the housing. This eliminates the need for separate connectors or contact terminals, as the housing itself serves as the electrical pathway between the sensing pad and touch sensor, thereby improving mounting efficiency while maintaining reliable electrical connection.
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 touch input recognition rates and reduces power consumption by accurately differentiating touch states and internal capacitance, while optimizing component mounting efficiency in wearable devices.
Implementation Method 1
a sensor electrically connected to the first conductive member through the switching circuit and configured to detect at least one of contact and proximity of an external object to the first conductive member
Data Source
AI summary
An electronic device and a method a provided. The electronic device includes a first surface, a second surface opposite to the first surface, and a side surface that surrounds at least part of a space between the first and second surfaces; a Radio Frequency (RF) communication circuit; an antenna radiator that forms at least part of at least one of the first surface, the second surface, and the side surface and is connected to the RF communication circuit; a sensor that detects whether an external object contacts the antenna radiator; a switching circuit connected to the antenna radiator and the sensor; and a processor configured to receive a first value from the sensor when the antenna radiator and the sensor are connected to each other and to receive a second value from the sensor when the antenna radiator and the sensor are separated from each other.