Patent ID: 9242273
Filing Date: 2016-01-26
CPC Classification: B06B,G01N,H01L

Claim Text:
1. A capacitive micromachined ultrasonic transducer (CMUT) comprising: a substrate; a CMUT plate disposed above the substrate, wherein a sealed cavity between the substrate and the CMUT plate is substantially evacuated; wherein the CMUT is configured to operate at an external gas pressure of about 1 atmosphere or more; wherein the CMUT plate makes partial contact with the substrate when no external bias voltage is applied to the CMUT due to the external gas pressure; wherein a contact between the CMUT plate and the substrate is configured to have a contact radius that varies with applied pressure; wherein the CMUT is configured such that an active part of the CMUT plate vibrates at an operating frequency of the CMUT during operation of the CMUT; wherein at least one electrode of the CMUT is configured as an annulus surrounding a contact zone where the CMUT plate makes contact with the substrate; wherein the annulus surrounds an electrically floating region of the CMUT, whereby an electric field in the contact zone is decreased.