Capacitive Proximity Sensing With Temperature Compensation for RF Control
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Solution Overview
Problem
Existing mobile devices face challenges in accurately detecting proximity to the human body, which affects the accuracy of proximity and touch detection, leading to potential health risks due to excessive RF radiation and reduced connectivity.
Innovation Solution
The implementation of a capacitive touch sensor system with a proximity sensor that uses a capacitive touch controller and a sensing element to accurately detect the proximity of a user's body by differentiating between environmental capacitance and human body capacitance, while also compensating for temperature and humidity changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RF power output is increased to maintain good connectivity, then connectivity is improved, but RF radiation exposure increases causing health risks
Solution Approach 1:
The system continuously monitors proximity sensor data and uses this feedback to dynamically adjust RF power output. When the proximity sensor detects that the device is close to the user's body, the system automatically reduces RF power to minimize radiation exposure while maintaining connectivity when the device is at a distance.
Solution Approach 2:
The RF power output is made dynamic rather than static, allowing the system to adapt its transmission power based on real-time proximity conditions. This enables the device to optimize between connectivity and radiation exposure by adjusting power levels according to the detected distance from the user's body.
2Measurement precision
If proximity detection sensitivity is increased to detect closer proximity, then proximity detection accuracy is improved, but false detection of environmental capacitance increases
Solution Approach 1:
The system extracts and compensates for environmental capacitance effects from the total capacitance measurement. By identifying and removing the environmental capacitance component, the system can focus on detecting only the human body capacitance, thereby improving proximity detection accuracy without false positives from environmental factors.
Solution Approach 2:
The system changes the measurement parameter by compensating for environmental capacitance variations. This allows the proximity sensor to maintain high sensitivity for detecting human body proximity while filtering out false signals caused by changes in environmental capacitance conditions.
3Measurement precision
If temperature and humidity compensation is added to improve detection accuracy, then proximity detection accuracy is improved, but device complexity increases
Solution Approach 1:
The capacitive touch sensor system performs multiple functions: it detects both touch input and proximity conditions, and simultaneously monitors environmental conditions like temperature and humidity. By making the sensor system multi-functional, the patent avoids adding separate dedicated sensors for each function, thereby improving detection accuracy without proportionally increasing device complexity.
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 solution enhances the accuracy of proximity detection, reduces RF radiation exposure to safe levels, and maintains good connectivity by dynamically adjusting the RF power output based on the detected proximity.
Implementation Method 1
a capacitive touch sensor system with a proximity sensor that uses a capacitive touch controller and a sensing element to accurately detect the proximity of a user's body by differentiating between environmental capacitance and human body capacitance
Implementation Method 2
compensating for temperature and humidity changes
Data Source
AI summary
A mobile device has a proximity sensor. A compensation value of the proximity sensor is determined. The compensation value is compared to a reference compensation value to determine validity of the compensation value. A capacitance of the proximity sensor is measured. A value of the capacitance of the proximity sensor is adjusted based on the compensation value. A coefficient defining a relationship between a capacitance of the proximity sensor and a temperature of the mobile device is calculated. A temperature sensor is coupled to the proximity sensor. The temperature of the mobile device is measured. A value of the capacitance of the proximity sensor is adjusted based on the coefficient and the temperature of the mobile device. The adjusted capacitance value is compared to a threshold capacitance value to determine proximity of an object to the mobile device. A radio frequency signal is adjusted by detecting proximity.