CMUT Membrane Structure for Low-Energy Collapse Mode
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Capacitive micromachined ultrasonic transducers operating in the collapse mode consume excessive energy, limiting their practical application due to high power consumption.
Innovation Solution
A transducer design featuring a substrate with a cave and island-shaped protrusion, a lower electrode, insulating layer, oscillating membrane, and upper electrode, manufactured through a process involving a sacrificial material layer and etching, allowing operation in a single collapse mode with low energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If capacitive micromachined ultrasonic transducers operate in the collapse mode, then coupling efficiency is improved, but energy consumption increases excessively
Solution Approach 1:
The oscillating membrane is divided into a contact portion and an oscillating portion, with the contact portion having a larger area than the oscillating portion. This segmentation allows the membrane to operate in a single collapse mode while maintaining lower energy consumption by distributing the mechanical stress and electrical field distribution more efficiently across the structure.
Solution Approach 2:
The insulating layer is disposed only on the lower electrode at the contact portion of the oscillating membrane, not across the entire membrane surface. This local application of insulation creates different electrical properties in different regions, enabling the contact portion to maintain stable electrical contact while the oscillating portion achieves high coupling efficiency with reduced energy loss.
2Stability of the object's composition
If capacitive micromachined ultrasonic transducers operate in the regular mode, then controlling stability is improved, but coupling efficiency deteriorates
Solution Approach 1:
The transducer is designed to operate in a single collapse mode where the oscillating membrane dynamically transitions between contact and non-contact states with the lower electrode. This dynamic operation mode provides both controlling stability through the defined contact state and high coupling efficiency during the oscillation phase, unlike the static regular mode.
Solution Approach 2:
By segmenting the oscillating membrane into contact and oscillating portions with different area ratios, the structure achieves stable control during the contact phase while maintaining high coupling efficiency during the oscillation phase, resolving the trade-off between stability and efficiency.
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 transducer achieves high coupling efficiency, wide frequency range, and flexible design options while significantly reducing energy consumption.
Implementation Method 1
A capacitive micromachined ultrasonic transducer includes a lower electrode, an oscillating membrane located above the lower electrode, and an upper electrode located on the oscillating membrane. By applying an electric field between the lower electrode and the upper electrode, the oscillating membrane may vibrate within the cavity, thereby generating ultrasonic waves.
Implementation Method 2
Ultrasonic transducers include bulk piezoelectric ceramic transducers, capacitive micromachined ultrasonic transducers, and piezoelectric micromachined ultrasonic transducers.
Data Source
AI summary
A transducer includes a substrate, a lower electrode, an insulating layer, an oscillating membrane, and an upper electrode. The substrate has a cave and an island-shaped protrusion defining the cave. The lower electrode is disposed in the cave and on the island-shaped protrusion of the substrate. The insulating layer is disposed on the lower electrode. The oscillating membrane includes a contact portion and an oscillating portion. The contact portion is in contact with the insulating layer and is located between the oscillating portion and the insulating layer. A cavity is located between the oscillating portion and the cave of the substrate. The upper electrode is disposed on the oscillating membrane. Moreover, a manufacturing method of the transducer is also provided.