Small scale, capacitive ultrasound transducer devices with improved directionality and methods for their use
Inventors
Moehring, Mark A. • KREINDLER, Daniel • Gates, George A. • Cameron, Caitlin E.
Assignees
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-12156764-B2
Publication Date
2024-12-03
Expiration Date
Abstract
An ultrasound transducer may include: a plurality of capacitive ultrasound transducer elements; and a base having a largest dimension sized and shaped to be disposed with an external ear canal, wherein the plurality of capacitive ultrasound transducers is mounted on the base. Each capacitive ultrasound transducer element and the ultrasound transducer are specifically constructed to achieve select desired performance characteristics. The ultrasound transducer may have an angular beam spread through a gaseous medium of greater than 15 degrees and an attenuation loss through the gaseous medium of greater than 10 dB measured at a distance 12.5 mm to 25 mm along a primary transmission axis of the ultrasound transducer. The ultrasound transducer may be particularly useful for characterizing fluid behind an ear drum to diagnose otitis media.
Core Innovation
The invention relates to an ultrasound transducer that includes a plurality of capacitive ultrasound transducer elements mounted on a base. The base has a largest dimension sized and shaped to be disposed with an external ear canal, and the transducer is configured for air-coupled ultrasound operation. The transducer is characterized by a fractional bandwidth that exceeds 10%, a projected intensity of about 10 Pa or more, and a signal to noise ratio greater than 15 dB measured at a distance 12.5 mm to 25 mm normal along a primary transmission axis.
The disclosed approach addresses transmission through a gaseous medium by using small-format capacitive micro-machined ultrasound transducer elements with air-coupled performance. The document ties the transducer operating configuration to measuring membrane and surface displacement under a pneumatic challenge, where a perturbation in a waveform reflected from a surface is observed in response to the pneumatic challenge. The resulting measurements are used to derive fluid properties from the reflected perturbation, including viscosity and elasticity.
The document further specifies structural and material features for the capacitive elements, including a microfabricated stack with a cavity height less than 1500 nm, electrical contact pads, and working-surface openings associated with release-slit designs. It also provides geometrical and performance and operating-parameter constraints relevant to the external ear canal form factor, including resonant frequency range and device size and edge length limits, and describes array element packing layouts and element counts.
Claims Coverage
The document contains three independent claims that share the same performance constraints for an air-coupled capacitive ultrasound transducer sized for an external ear canal, and that differ by whether they cover the transducer itself, measuring a fluid using a pneumatic challenge, or characterizing a fluid by directing an ultrasound beam through a gaseous medium. The independent claims collectively include inventive features centered on the external ear canal base sizing and the stated fractional bandwidth, projected intensity, and signal-to-noise ratio at a specified distance along a primary transmission axis.
External ear canal base with capacitive element ultrasound performance constraints
An ultrasound transducer comprising a plurality of capacitive ultrasound transducer elements mounted on a base having a largest dimension sized and shaped to be disposed with an external ear canal, wherein the transducer has a fractional bandwidth that exceeds 10%, a projected intensity of about 10 Pa or more, and a signal to noise ratio greater than 15 dB measured at a distance 12.5 mm to 25 mm normal along a primary transmission axis.
Pneumatic challenge fluid measuring with reflected waveform perturbation observation
A method of measuring a fluid including providing an ultrasound transducer with a base sized and shaped to be disposed with an external ear canal and with fractional bandwidth exceeding 10%, projected intensity of about 10 Pa or more, and signal to noise ratio greater than 15 dB at 12.5 mm to 25 mm normal along a primary transmission axis, applying a pneumatic challenge to a surface of the fluid, and observing with the capacitive ultrasound transducer a perturbation in a waveform reflected from the surface in response to the pneumatic challenge.
Gaseous-medium beam direction for fluid characterization at ear-canal distance
A method of characterizing a fluid including providing an ultrasound transducer and directing an ultrasound beam generated by the ultrasound transducer toward a surface through a gaseous medium, wherein the surface is at a distance of 12.5 mm to 25 mm from a working surface of the ultrasound transducer and the ultrasound beam has a fractional bandwidth exceeding 10%, projected intensity of about 10 Pa or more, and a signal to noise ratio greater than 15 dB measured at a distance 12.5 mm to 25 mm normal along a primary transmission axis.
Across the independent claims, the core inventive coverage is an air-coupled capacitive ultrasound transducer with a base sized for an external ear canal and specified fractional bandwidth, projected intensity, and signal-to-noise ratio at 12.5 mm to 25 mm along a primary transmission axis, together with methods that use that transducer to measure a fluid surface under a pneumatic challenge or to characterize a fluid by directing an ultrasound beam through a gaseous medium to a surface at the specified distance.
Stated Advantages
Provides a fractional bandwidth exceeding 10%.
Provides a projected intensity of about 10 Pa or more.
Provides a signal to noise ratio greater than 15 dB measured at 12.5 mm to 25 mm normal along a primary transmission axis.
Documented Applications
Measuring a fluid by applying a pneumatic challenge to a surface of the fluid and observing a perturbation in a waveform reflected from the surface.
Characterizing a fluid by directing an ultrasound beam toward a surface through a gaseous medium.
Interested in licensing this patent?