Voice Coil Temperature Sensing via Resistance Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional temperature sensors for electromagnetic actuators are bulky and power-consuming, making them challenging to integrate into electronic devices like mobile devices, which can lead to overheating of sensitive components such as electronic displays.
Innovation Solution
A temperature sensor system using three electrical terminals spaced along a voice coil to measure resistance changes, allowing for the estimation of temperature gradients and component temperatures without additional bulk or power consumption, thereby approximating panel temperatures effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional temperature sensor is attached to the voice coil or attached components, then temperature monitoring capability is improved, but the weight and bulk of the device increases
Solution Approach 1:
The voice coil serves dual functions: it generates magnetic fields for actuator operation and simultaneously functions as a temperature sensor through its inherent resistance changes with temperature. By measuring resistance across the coil windings, the system obtains temperature data without requiring separate sensing components, thus avoiding additional weight and bulk.
Solution Approach 2:
The voice coil is designed to perform multiple functions: electromagnetic actuation and temperature sensing. The same coil structure and electrical connections are utilized for both driving the actuator and monitoring temperature, eliminating the need for dedicated temperature sensor components and reducing overall device weight.
2Measurement precision
If a conventional temperature sensor is attached to the voice coil or attached components, then temperature monitoring capability is improved, but power consumption increases
Solution Approach 1:
The voice coil's electrical resistance, which naturally changes with temperature, is directly measured to obtain temperature information. This approach utilizes the existing electrical properties of the coil without requiring additional power-hungry sensing circuits or separate temperature sensor power supplies, thereby minimizing power consumption.
Solution Approach 2:
The patent replaces conventional temperature sensing mechanisms with electrical resistance measurement of the voice coil itself. By using the coil's inherent electrical properties for temperature detection rather than separate thermal sensing elements, the system reduces overall power consumption while maintaining temperature monitoring capability.
3Power
If the voice coil is energized to operate the actuator, then actuator functionality is improved, but temperature of the coil and attached components increases
Solution Approach 1:
The system continuously monitors the voice coil's resistance to detect temperature changes during operation. This real-time temperature feedback enables the control system to adjust actuator power levels, duty cycles, or operational parameters to prevent excessive heating, thereby maintaining actuator functionality while controlling temperature rise.
Solution Approach 2:
By monitoring resistance changes that indicate temperature rise before critical overheating occurs, the system can take preventive actions such as reducing power output or increasing cooling measures. This preliminary detection and response prevents the temperature from reaching harmful levels while maintaining actuator performance.
4Power
If the coil temperature increases, then actuator power output can be maintained, but heat is transferred to sensitive components like electronic displays causing overheating
Solution Approach 1:
The resistance measurement provides real-time feedback on coil temperature, enabling the control system to monitor heat generation during actuator operation. This feedback allows dynamic adjustment of power delivery to maintain required actuator output while preventing excessive heat transfer to adjacent sensitive components like electronic displays.
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 allows for accurate temperature monitoring of voice coil actuators and attached components with minimal additional components, reducing weight and power consumption, while preventing overheating of sensitive components like OLED displays.
Implementation Method 1
When the coil is energized by an electric current, the temperature of the coil increases. Because the resistance across the coil increases when the coil's temperature increases, it is possible to deduce a temperature gradient along the length of the coil based on resistance measurements across the different lengths of the coil.
Implementation Method 2
A temperature sensor has connections to each of the three terminals, and the temperature sensor can measure the resistance across each of the two portions and across the entire length of the coil.
Data Source
AI summary
A panel audio loudspeaker having a panel extends in a plane and an actuator is coupled to the panel. The actuator includes a voice coil attached to and extending from the panel along an axis, a magnet assembly suspended from the panel via one or more springs, and a temperature sensor in electrical contact with the coil at three different axial locations. The temperature sensor is configured, during operation of the device, to measure a temperature of the coil based on voltage measurements at the three different axial locations.