Variable-Resonance Ultrasonic Receiver for Blind-Zone Reduction
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Solution Overview
Problem
Ultrasonic sensors suffer from a blind zone due to strong parasitic mechanical vibrations, which prevent accurate detection of objects at short distances, and existing methods fail to effectively reduce or eliminate this issue.
Innovation Solution
A device that modulates the resonant frequency of the receiver to reduce its sensitivity during the direct wave reception, thereby minimizing the blind zone by reducing the amplitude of parasitic oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the receiver maintains high resonant frequency sensitivity for detecting echo signals, then the detection sensitivity is improved, but the blind zone increases due to strong parasitic vibrations from direct waves
Solution Approach 1:
The patent applies dynamics by making the resonant frequency of the receiver time-variable rather than fixed. The resonant frequency modulator dynamically adjusts the receiver's resonant frequency to be different from the transmitter's frequency during the direct wave reception period, and then restores it to match the transmitter frequency for echo detection. This dynamic adjustment allows the system to adapt its sensitivity in different time phases, reducing parasitic vibrations when receiving direct waves while maintaining high detection sensitivity when receiving echo signals.
Solution Approach 2:
The patent implements periodic action through cyclic modulation of the receiver's resonant frequency. The resonant frequency is periodically adjusted in synchronization with the transmission-reception cycle: during the direct wave reception phase, the resonant frequency is shifted away from the transmitter frequency to minimize parasitic oscillations, and during the echo detection phase, it is restored to match the transmitter frequency for maximum sensitivity. This periodic modulation pattern enables the system to alternately optimize for different operational requirements.
2Reliability
If the receiver is highly sensitive to direct waves for accurate signal reception, then the signal reception quality is improved, but the parasitic vibrations increase causing blind zone
Solution Approach 1:
The patent applies preliminary anti-action by proactively reducing the receiver's sensitivity to direct waves before the direct wave arrives. The resonant frequency modulator预先 adjusts the resonant frequency to be different from the transmitter frequency during the period when direct waves are expected, thereby preventing strong parasitic vibrations from being generated in the first place. This preventive measure ensures that when direct waves are received, the receiver is already in a low-sensitivity state, minimizing harmful parasitic oscillations while still allowing the system to subsequently detect echo signals with high sensitivity.
3Measurement precision
If the resonant frequency is kept constant for optimal echo detection, then the detection accuracy is improved, but the blind zone cannot be reduced
Solution Approach 1:
The patent applies parameter changes by modifying the resonant frequency parameter of the receiver over time. Instead of keeping the resonant frequency constant, the system dynamically changes this parameter in response to different operational phases. During direct wave reception, the resonant frequency is shifted to reduce parasitic vibrations, and during echo detection, it is restored to optimize sensitivity. This parameter modulation is achieved through a relatively simple resonant frequency modulator that adjusts the receiver's electrical characteristics, demonstrating that significant performance improvements can be obtained through parameter variation without requiring complex system architecture.
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 solution effectively reduces the blind zone by minimizing parasitic vibrations, allowing accurate detection of objects at shorter distances without increasing the sensor's sensitivity to direct waves.
Implementation Method 1
a pulse of electrical energy can vibrate a piezoelectric transducer at a given frequency due to piezoelectricity
Implementation Method 2
capacitive cMUT type
Implementation Method 3
detect the distance to an object based on the speed of sound propagation
Implementation Method 4
capacitive cMUT type
Implementation Method 5
modulate the resonant frequency of the receiver so that it is less sensitive
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a device (1) for emitting and/or receiving acoustic waves, preferably ultrasonic, comprising: a wave emitter (2) configured to transmit waves at an emission frequency and a wave receiver (3) preferably ultrasonic waves, preferably separate from the emitter (2) having a resonant frequency and configured to receive waves generated by the emitter (2) and comprising direct waves (6) and reflected waves (7), characterized in that the device comprises a modulator of the resonant frequency of the receiver (3) and a control unit configured to control the resonant frequency modulator during a predetermined period of time so as to reduce the sensitivity of the receiver (3) during said predetermined period of time by moving the resonant frequency of the receiver (3) away from the emission frequency of the emitter (2).The invention relates to the field of ultrasonic sensors, particularly pMUTs or cMUTs, having a high quality factor.