Ultrasonic Sensor Array Chip for Short Distance Measurement
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Solution Overview
Problem
Bulk-type ultrasonic sensors face challenges in reducing size and increasing frequency, making it difficult to measure short distances and detect shape irregularities of target objects, as they struggle to attenuate reverberation time and reduce spot diameter effectively.
Innovation Solution
An ultrasonic sensor with an ultrasonic array chip featuring a rectangular shape and a resonance frequency of 2000 kHz or less, where ultrasonic elements are arranged in an array, allowing for a reverberation time of 60 μs or less, enabling precise detection of short distances and surface irregularities by forming an ultrasonic beam with a spot diameter of 10 mm or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the resonance frequency of the ultrasonic element is increased to reduce reverberation time for short distance measurement, then the measurement precision for short distances is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The ultrasonic element is divided into a vibrating section and a non-vibrating section. The vibrating section has a size that allows resonance at high frequencies (2000 kHz or more), while the non-vibrating section provides structural support and electrical connection. This segmentation enables the element to achieve high-frequency resonance necessary for short distance measurement without requiring the entire element structure to be miniaturized, thus reducing manufacturing complexity while maintaining measurement precision.
Solution Approach 2:
Different sections of the ultrasonic element are designed with different properties: the vibrating section is optimized for high-frequency vibration with appropriate dimensions and material properties, while the non-vibrating section is designed for mechanical strength and electrical connectivity. This local differentiation allows the element to resonate at high frequencies locally without compromising overall structural integrity, resolving the contradiction between measurement precision and device complexity.
2Measurement precision
If the ultrasonic element size is reduced to achieve small spot diameter for detecting surface irregularities, then the measurement precision for surface shape is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The ultrasonic element is segmented into vibrating and non-vibrating sections with distinct functional requirements. The vibrating section can be made small to achieve a focused ultrasonic beam with small spot diameter for precise surface irregularity detection, while the non-vibrating section maintains larger dimensions to facilitate manufacturing and provide robust mechanical and electrical connections. This segmentation allows the critical vibrating portion to be optimized for measurement precision without imposing equally stringent manufacturing requirements on the entire element.
Solution Approach 2:
The vibrating section is designed with local properties optimized for high-frequency vibration and small spot diameter, while the non-vibrating section has properties optimized for manufacturability and structural support. This local quality differentiation enables the small vibrating section to achieve precise surface detection without requiring the entire element to meet equally high manufacturing precision standards, thus resolving the contradiction between measurement precision and manufacturing precision.
3Measurement precision
If the reverberation time is reduced to enable short distance measurement, then the measurement precision is improved, but the energy loss increases
Solution Approach 1:
Instead of attempting to reduce reverberation time by increasing frequency (which would cause high energy loss), the patent inverts the approach by using a lower frequency (2000 kHz or less) and accepting a longer reverberation time. This inversion allows the system to achieve sufficient measurement precision for short distances without the prohibitive energy loss that would result from using much higher frequencies, thus resolving the contradiction between measurement precision and energy loss.
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 ultrasonic sensor effectively measures distances as close as 10 mm and detects surface irregularities with high precision, suppressing reverberation vibration and maintaining a small spot diameter, outperforming bulk-type sensors in terms of size and frequency capabilities.
Implementation Method 1
Each of the ultrasonic elements includes a vibrating section and a piezoelectric element provided in the vibrating section, vibrates the vibrating section with voltage application to the piezoelectric element to transmit the ultrasonic wave
Implementation Method 2
detects reception of the ultrasonic wave with a signal output from the piezoelectric element by the vibration of the vibrating section
Implementation Method 3
A reverberation time of the ultrasonic element is 60 μs or less, the reverberation time being a time until vibration amplitude of the vibrating section caused by transmitting the ultrasonic wave from the ultrasonic element decreases to 10% or less
Data Source
AI summary
An ultrasonic sensor is a sensor that transmits an ultrasonic wave to a target object and receives the ultrasonic wave reflected by the target object, the ultrasonic sensor including an ultrasonic array chip on which ultrasonic elements that transmit and receive the ultrasonic wave are arranged in an array shape. Each of the ultrasonic elements includes a vibrating section and a piezoelectric element provided in the vibrating section, vibrates the vibrating section to transmit the ultrasonic wave, and outputs a reception signal of the ultrasonic wave by the vibration of the vibrating section. A resonance frequency of the ultrasonic element is 2000 kHz or less.