Touch Detection System Temperature Compensation Acoustic Waves
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Solution Overview
Problem
Existing touch detection and localization systems on tactile surfaces are sensitive to temperature variations, which can degrade their reliability, especially in applications like automotive environments where temperature fluctuations are significant.
Innovation Solution
A system that uses at least two distinct sources for emitting volume acoustic waves, a receiver for capturing the waves after propagation, and means to adapt spectral characteristics of the reception signal by frequency shift based on measured temperature, allowing for reliable touch detection and localization across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spectral analysis is used to improve sensitivity and reduce transducer count, then measurement precision and device complexity are improved, but reliability deteriorates due to temperature sensitivity
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the frequency reference based on measured temperature. The system measures temperature and uses it to modify the frequency reference, compensating for temperature-induced frequency shifts in the acoustic waves. This allows the spectral analysis method to maintain its precision while becoming reliable across varying temperature conditions.
2Measurement precision
If resonance figures are used for touch detection, then measurement precision is improved, but reliability deteriorates due to sensitivity to temperature variations affecting absorption signature
Solution Approach 1:
The patent uses parameter changes by measuring temperature and adjusting the frequency reference accordingly. This compensation mechanism allows the system to maintain accurate touch location detection despite temperature variations that would otherwise alter the absorption signature of acoustic waves in the glass.
3Reliability
If impulse diffraction figures are used instead of resonance figures, then reliability is improved by removing dependence on natural frequencies, but measurement precision deteriorates due to sensitivity to temperature variations affecting diffraction pulse figures
Solution Approach 1:
The patent applies parameter changes by using temperature measurements to adjust the frequency reference. This compensation allows impulse diffraction figures to maintain their advantage of independence from natural frequencies while achieving temperature stability, thereby preserving measurement precision across varying temperature conditions.
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
The system maintains reliable touch detection and localization by adjusting spectral characteristics to compensate for temperature changes, enhancing its resistance to temperature variations and ensuring consistent performance.
Implementation Method 1
at least two distinct sources for the emission of volume acoustic waves in the touch-sensitive surface, arranged so as to generate acoustic interference between the waves emitted
Implementation Method 2
arranged so as to generate acoustic interference between the waves emitted
Implementation Method 3
at least one receiver of the volume acoustic waves after their propagation and their interference in the surface tactile, designed to supply a reception signal from the acoustic waves received
Implementation Method 4
means for measuring a temperature of the touch surface
Implementation Method 5
means for adapting the spectral characteristics of the reception signal or the reference spectral characteristics by frequency shift of at least a part of these spectral characteristics as a function of the measured temperature
Data Source
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AI summary
The invention relates to a system (10, 30) for detecting and locating at least one touch on a touch-sensitive surface (24) of an object, comprising: at least two different sources (E1, E2) for emitting bulk acoustic waves in the touch-sensitive surface, disposed such as to generate acoustic interferences between the emitted waves; at least one receiver (R+, R-) for receiving bulk acoustic waves after they have been propagated and received interference in the touch-sensitive surface, designed to supply a reception signal from the received acoustic waves; and means (60) for locating at least one touch on the touch-sensitive surface (24) of the object, by comparing certain spectral characteristics of the reception signal (FFT(R(t))) to a set of reference spectral characteristics (62). The system also comprises means (46) for measuring a temperature of the touch-sensitive surface (24) and means (56) for adapting the spectral characteristics of the reception signal (FFT(R(t))) or the reference spectral characteristics (62) by means of the frequency shifting of at least part of the spectral characteristics according to the measured temperature (T).