Acoustic Proximity Detection Using Spectral Differences
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Solution Overview
Problem
Existing mobile devices face challenges in accurately determining whether they are held next to a user's ear or in front of the user without requiring expensive additional sensor arrangements, which increases production costs and energy consumption.
Innovation Solution
A proximity sensor arrangement using at least one first and second acoustic transducer, along with a comparing means, to evaluate the spectral differences in acoustic signals received by these transducers, allowing for the detection of proximity to a user's ear without additional hardware, by utilizing the acoustic transfer functions within the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sensor arrangements (proximity sensors, light sensors, ultrasonic sensors) are added to detect device position, then detection accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies multi-functionality by using existing acoustic transducers (microphones and loudspeakers) that serve dual purposes: their primary function for audio communication and an additional function for proximity detection. By analyzing the acoustic transfer function between these transducers, the system determines device position without requiring separate sensor hardware, thereby maintaining detection accuracy while reducing manufacturing costs.
2Measurement precision
If additional sensor arrangements are added to detect device position, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The system uses existing acoustic transducers for dual purposes, avoiding additional hardware components and reducing device complexity.
Solution Approach 2:
The patent replaces physical sensor hardware with a signal processing approach. By analyzing the acoustic transfer function between existing transducers through digital signal processing, the system achieves proximity detection without mechanical or physical sensors, thereby reducing device complexity.
3Measurement precision
If additional sensor arrangements are added to detect device position, then detection accuracy is improved, but energy consumption increases
Solution Approach 1:
The system reuses existing acoustic transducers that are already powered for audio communication, eliminating the need for additional power-hungry sensor components. The acoustic transfer function analysis uses signal processing on existing audio data, requiring minimal additional energy.
Solution Approach 2:
The system uses the acoustic signals already being transmitted and received for communication purposes to simultaneously perform proximity detection. The existing audio signal serves dual purposes, eliminating the need for separate energy-consuming detection mechanisms.
4Measurement precision
If complex signal analysis is performed to detect device position, then detection accuracy is improved, but processing time and computational resources increase
Solution Approach 1:
The patent replaces complex signal analysis with a more efficient approach based on acoustic transfer function analysis. By characterizing the frequency response between transducers and comparing it to reference profiles, the system achieves accurate position detection with reduced computational complexity and faster processing time.
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 enables efficient and cost-effective detection of the device's position relative to the user, allowing for automatic adjustment of display and keypad settings, such as turning off the display during calls, without complex signal analysis or additional hardware, thereby conserving energy and reducing production costs.
Implementation Method 1
The acoustic transducers are adapted to receive acoustic signals and to convert the received acoustic signals into electric signals
Data Source
Figure 1(a)~2
Figure 3~4
Figure 4a~4b
AI summary
A proximity sensor arrangement is provided comprising at least one first and at least one second acoustic transducer and at least one comparing means. The acoustic transducers are adapted to receive acoustic signals and convert the received acoustic signals into electric signals. The comparing means are adapted to compare the spectra received by the acoustic transducers. If the device comprising the proximity sensor arrangement is held at a user's ear, the signal received by the covered microphone is low-pass filtered due to human tissue and/or the presence of the human head, resulting in a spectral difference between several microphones. Furthermore a method is provided comprising the steps of receiving an acoustic signal at at least two locations distant from each other. In a second step, said received acoustic signals are converted into electric signals. Subsequently, the actual proximity and/or coverage situation is deduced from the spectral difference between the electric signals.