Vertical Gap Actuator For Ultrasonic Transducers And Fabricatıon Of The Same

Applications: Medical Imaging, Ultrasound Imaging

Problem:

In order to address the limitations of piezoelectric transducers, capacitive micromachined ultrasonic transducers (CMUTs) have been introduced. Since the first introduction of CMUTs, extensive research has been performed on fabrication, modeling and applications. Main challenges of CMUTs can be traced to lack of high sound pressure generation, low receive sensitivity and highly nonlinear behavior of the parallel plate actuation. There was a need for a new actuation method for the CMUT transducers that will separate the dependence of the output pressure and receive sensitivity on the gap.

Technology:

The main objective of this invention is to develop novel cell geometry for CMUT transducers where the sensitivity and the maximum output pressure do not have conflicting requirements over the gap.This is achieved by defining the gap between a piston type section of the membrane and the sidewalls. In this geometry, the motion of the membrane does not affect the height of the gap where the actuation forces is built. Also there are large cavities under the membrane in the horizontal direction such that these cavities do not interfere with the membrane motion even for large membrane displacement amplitudes. This enables membrane to move without any hard limits.

Advantages:

• To solve the low output pressure problem of CMUTs
• Increase in the receive sensivity
• Cost reduction

Keywords: ultrasound imaging, medical imaging, transducer, CMUT