Hydrophone Array Module Using Electret Film and FETs
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Solution Overview
Problem
Existing longitudinal wave sensors, such as hydrophones, are labor-intensive to manufacture and not suitable for mass production due to their limited design and use, often requiring skilled technicians and are not easily adaptable for creating images or transmitting waves effectively.
Innovation Solution
A flat panel longitudinal wave sensor array utilizing a compressible electret film with an outer electrode and an array of inner electrodes connected to field-effect transistors (FETs), allowing for the creation of an image or transmission of longitudinal waves by varying the thickness of the electret film in response to pressure changes, with the FETs acting as amplifiers or drivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single-element hydrophone design is used, then the device can detect acoustic energy, but the manufacturing process is labor-intensive and not suitable for mass production
Solution Approach 1:
The patent divides the hydrophone into multiple independent elements arranged in an array, with each element having its own FET connected to a shared readout line. This segmentation allows parallel manufacturing of multiple elements while maintaining individual detection capabilities, thereby improving productivity without excessive complexity increase
Solution Approach 2:
The patent creates a multi-functional device that can both detect acoustic energy and transmit longitudinal waves by applying voltage to the electret film. The same basic structure serves dual purposes, reducing the need for separate devices and improving manufacturing efficiency
2Productivity
If standard masking and sputtering techniques are used to form electrodes, then the electrodes can be created, but the process is not easily adaptable for mass production
Solution Approach 1:
The electrode structure is segmented into inner electrodes and an outer electrode that can be manufactured separately and then assembled. This allows each component to be optimized for mass production using standard techniques while the final assembly creates the functional array
Solution Approach 2:
The electret film is prepared with electrodes in advance, and the FETs are pre-assembled on the substrate before final integration. This preliminary preparation of components facilitates mass production by allowing parallel processing of different sub-assemblies
3Productivity
If skilled technicians hand-make the hydrophones, then the devices can be assembled, but the process is very labor intensive
Solution Approach 1:
The hydrophone array is segmented into modular units with standardized interfaces, allowing automated assembly equipment to position and connect components precisely without requiring skilled manual intervention for each element
Solution Approach 2:
The patent introduces intermediate structures such as the substrate and readout lines that mediate between individual hydrophone elements and the final assembled array. These intermediaries provide standardized connection points that facilitate automated assembly while maintaining precision
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 configuration enables efficient and cost-effective production of hydrophone arrays suitable for medical imaging, biometric identification, and underwater sonar applications, offering improved manufacturing efficiency and enhanced performance in detecting and transmitting longitudinal waves.
Implementation Method 1
an electret film 2 ('E film'). The molecules of the E film 2 are aligned so as to create a permanent electrostatic field
Implementation Method 2
The two electrodes 3, 4 with the E film 2 between form a capacitor. When the distance between the electrodes 3, 4 changes, the voltage differential between the electrodes 3, 4 changes
Implementation Method 3
Each of the inner electrodes in the array may be connected directly or indirectly to a field-effect transistor ('FET'). The FETs may be arranged in an array on an insulating substrate
Data Source
AI summary
A hydrophone array includes hydrophones having an electret means and may have TFT FETs to generate current in response to received longitudinal wave signals. The arrangement may also be used to transmit longitudinal wave signals. Storage capacitors may be coupled to each TFT FET output to act as sample and hold means. Digital switches may allow the sample and hold circuit to both reset and measure the output of the hydrophone element. Data lines may be used to indicate the location of the received signal on the longitudinal wave detector sensor array.