Ultrasound transducer device and method

Abstract

An ultrasonic transducer can include a plurality of capacitive ultrasonic transducer elements and a base having a maximum dimension sized and shaped to be disposed within an external ear canal, wherein the plurality of capacitive ultrasonic transducer elements are mounted on the base. Each capacitive ultrasonic transducer element and the ultrasonic transducer are specifically constructed to achieve selected desired performance characteristics. The ultrasonic transducer can have an angular beam that propagates through a gaseous medium that is greater than 15 degrees and an attenuation loss through the gaseous medium that is greater than 10 dB measured at a distance of 12.5 mm to 25 mm along a primary transmission axis of the ultrasonic transducer. The ultrasonic transducer can be particularly useful for characterizing fluid behind a tympanic membrane to diagnose otitis media.

Description

[0001] Cross-referencing

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 892,930, filed August 28, 2019, which is incorporated herein by reference. Background Technology

[0003] The determination of membrane elasticity or fluid viscosity can be of interest in a variety of fields, including medical diagnostics, medical imaging, manufacturing quality control, food characterization, and industrial process analysis. In many applications, measuring reflected ultrasonic signals using small air-coupled transducers can be beneficial. However, the small size can pose significant challenges to transducer performance.

[0004] In one example, characterizing the fluid adjacent to a biofilm may be beneficial. Physical access to the biofilm may be limited. Furthermore, coupling gels may not be suitable for certain biofilms. Given these considerations, there is a need for improved systems, apparatus, and methods for small air-coupled ultrasound devices.

[0005] This application may relate to jointly owned U.S. Patent Publication 2018 / 0310917 and U.S. Patent Publication 2017 / 0014053, each of which is incorporated herein by reference in its entirety.

[0006] The following references may be of interest: U.S. Patent 7,545,075, U.S. Patent 8,531,919, U.S. Patent 9,925,561, U.S. Patent 9,925,561, U.S. Patent 7,545,075, U.S. Patent Publication 2014 / 0265720, U.S. Patent Publication 2010 / 0173437, U.S. Patent Publication 2014 / 0265720, and U.S. Patent Publication 2012 / 0068571, each of which is incorporated herein by reference in its entirety. Summary of the Invention

[0007] Traditional ultrasonic transducers may require the use of a coupling fluid to match the impedance of the material to be characterized to the ultrasonic transducer, because the typical medium between the material and the transducer (e.g., air) may have an acoustic impedance that is significantly mismatched with the transducer and / or the material being measured. Therefore, some applications may require air-coupled transducer devices. In one example, it might be necessary to use air-coupled ultrasound to characterize the fluid on the opposite side of the eardrum, rather than filling the ear canal with ultrasonic gel. Similarly, in this example, it might be desirable to simultaneously miniaturize the device to reduce the scattering of ultrasound with air and the loss of coherence. Sufficient strength, spatial coherence, low divergence, and / or phase stability, which may be difficult to achieve with air-coupled transducer devices and systems, can be further compromised by making the transducer device smaller.

[0008] This disclosure provides ultrasonic transducer elements, ultrasonic transducers, and systems and methods for using and manufacturing the same.

[0009] This document discloses an ultrasonic transducer comprising multiple capacitive ultrasonic transducer elements; and a base having a maximum dimension, the size and shape of which are adjusted for placement within the external auditory canal, wherein the multiple capacitive ultrasonic transducer elements are mounted on the base; wherein the ultrasonic transducers have an angular beam propagating through a gas medium of greater than 15 degrees and an attenuation loss through the gas medium of greater than 10 dB measured along the main transmission axis of the ultrasonic transducer at a distance of 12.5 mm to 25 mm. The maximum dimension of the base can be less than 3 mm. The multiple capacitive ultrasonic transducer elements can have a resonant frequency between 1.0 MHz and 3.0 MHz. Each capacitive ultrasonic transducer element can have a working surface with a diameter between 10 and 100 micrometers. The ultrasonic transducer can have an edge length of less than 1.5 mm. The multiple capacitive ultrasonic transducer elements can include at least 20 capacitive ultrasonic transducer elements. The multiple ultrasonic transducers can have an average capacitance between 2.5 pF and 10.0 pF. An ultrasonic transducer can be configured to be positioned within the endoscope of an otoscope. One or more of a plurality of capacitive ultrasonic transducer elements may have multiple openings in the working surface of one or more of the transducer elements. The multiple openings may be arranged in a circular pattern with a diameter of at least 10 micrometers. The multiple openings may include at least three release holes for each capacitive ultrasonic transducer element. The shape of the multiple openings may be circular. The shape of the multiple openings may be curved. The multiple openings may include release slits having a slit width of at least 0.4 micrometers and a spring length of at least 2 micrometers. The multiple ultrasonic transducer elements may be arranged on a base in a hexagonal close-packed structure. The multiple ultrasonic transducer elements may be arranged within a circular region on the base, the diameter of which is equal to the edge length. The multiple ultrasonic transducer elements may be arranged within a rectangular region on the base, the longest side of which is equal to the edge length.

[0010] The ultrasonic transducer may also include multiple pads forming multiple electrical contacts. Multiple capacitive ultrasonic transducer elements can have an average cavity height of less than 1500 nm. The ultrasonic transducer can have a pull-in voltage of less than 80% of 85 V. The ultrasonic transducer can have a signal-to-noise ratio greater than 15 dB measured along the transducer's main transmission axis at a distance of 12.5 mm to 25 mm. The ultrasonic transducer can have a partial bandwidth exceeding 10%. The ultrasonic transducer can have a projected intensity of approximately 10 Pa or greater measured along the transducer's main transmission axis at a distance of 12.5 mm to 25 mm. The ultrasonic transducer can have a frequency bandwidth of ±25% of the center frequency at half-width at half-height.

[0011] This paper discloses an ultrasonic transducer comprising multiple capacitive ultrasonic transducer elements; and a base having a maximum dimension, the size and shape of which are adjusted for placement within the external auditory canal, wherein the multiple ultrasonic transducer elements are mounted on the base, and wherein the ultrasonic transducers have a partial bandwidth exceeding 10%, a projected intensity of approximately 10 Pa or greater, and a signal-to-noise ratio greater than 15 dB measured along the main transmission axis of the ultrasonic transducer at a distance of 12.5 mm to 25 mm. The multiple capacitive ultrasonic transducer elements may have a resonant frequency between 1.0 MHz and 3.0 MHz. The ultrasonic transducer may have an average capacitance between 2.5 pF and 10.0 pF. The ultrasonic transducer may have a pull-in voltage of less than 85 V. The ultrasonic transducer may have an edge length of less than 1.5 mm. The ultrasonic transducer may have an angular beam propagating through a gas medium of less than 30 degrees and an attenuation loss through a gas medium of less than 45 dB measured perpendicular to the working surface of the transducer elements at a distance of 12.5 mm to 25 mm. Multiple capacitive ultrasonic transducer elements may include at least 20 capacitive ultrasonic transducer elements. Each capacitive ultrasonic transducer element may have a device radius between 30 micrometers and 100 micrometers. The ultrasonic transducer may be configured to be disposed within the endoscope of an otoscope. One or more of the multiple capacitive ultrasonic transducer elements may have multiple openings in the working surface of one or more of the transducer elements. The multiple openings may be arranged in a circular shape with a diameter greater than 5 micrometers. The multiple openings may include at least three release holes for each capacitive ultrasonic transducer element. The shape of the multiple openings may be circular. The shape of the multiple openings may be curved. The multiple openings may have a release slit with a slit width of at least 0.4 micrometers and a spring length of at least 2 micrometers. The multiple ultrasonic transducer elements may be arranged in a hexagonal close-packed structure. The multiple ultrasonic transducer elements may be arranged within a circular region, the diameter of which is equal to the edge length. The multiple ultrasonic transducer elements may be arranged within a rectangular region, the longest side of which is equal to the edge length. The ultrasonic transducer may also include multiple pads that form multiple electrical contacts. Multiple capacitive ultrasonic transducer elements can have an average cavity height of less than 1500 nm. The ultrasonic transducer can have a pull-in voltage of less than 80% of 85 V. The ultrasonic transducer can have a frequency bandwidth of ±25% of the center frequency at full width at half maximum (FWHM). This document discloses a system comprising: the capacitive ultrasonic transducer of this disclosure and a trocar, wherein the capacitive ultrasonic transducer is disposed within the trocar and wherein the trocar is configured to be removably coupled to an otoscope. This document discloses a method for measuring fluids, the method comprising: providing the capacitive ultrasonic transducer of this disclosure; applying an aerodynamic challenge to the surface of the fluid; and observing, with the capacitive ultrasonic transducer, disturbances in a waveform reflected from the surface in response to the aerodynamic challenge.This paper discloses a method for characterizing fluids, comprising: providing an ultrasonic transducer; and guiding an ultrasonic beam generated by the ultrasonic transducer through a gaseous medium to the surface of a fluid, wherein the fluid is 12.5 mm to 25 mm away from the working surface of the ultrasonic transducer, wherein the ultrasonic beam has an angular beam with a propagation angle greater than 15 degrees through the gaseous medium, and wherein the ultrasonic beam has an attenuation loss greater than 10 dB through the gaseous medium. This paper also discloses a method for characterizing fluids behind the eardrum in the ear canal, comprising: receiving a set of data from an ultrasonic transducer, wherein the ultrasonic transducer is disposed within the ear canal of a subject, wherein the ultrasonic transducer has an edge length of less than 1.5 mm; determining from the set of data a first subset of data corresponding to a response to an aerodynamic challenge and a second subset of data corresponding to a dataset without a challenge; determining the viscosity of the fluid; and classifying the fluid.

[0012] This document discloses an otoscope, comprising a disposable trocar; a plurality of capacitive ultrasonic transducers disposed within the trocar, wherein the plurality of ultrasonic transducer elements form an ultrasonic transducer, wherein the ultrasonic transducer is disposed within the tip of the trocar, and wherein the ultrasonic transducer has an angular beam propagating through a gas medium of greater than 15 degrees and an attenuation loss through a gas medium of greater than 10 dB measured along the main transmission axis of the transducer at a distance of 12.5 mm to 25 mm; and a base, wherein the base includes a maximum dimension of less than 2.5 mm, wherein the plurality of capacitive ultrasonic transducers are disposed on the base.

[0013] This document discloses a method for manufacturing a fluid measurement device, the method comprising: forming a plurality of capacitive ultrasonic transducer elements on a wafer surface having a device radius between 10 micrometers and 100 micrometers, wherein the plurality of ultrasonic transducer elements are arranged in a hexagonal close-packed structure, wherein one or more of the plurality of ultrasonic transducer elements includes a plurality of openings in the working surface of one or more of the transducer elements, wherein the plurality of openings includes 4 to 20 openings; dicing the wafer into a plurality of individual capacitive ultrasonic transducers; and mounting a single ultrasonic transducer within a trocar of an otoscope. The method may further include removably coupling the trocar to the otoscope.

[0014] Incorporation

[0015] All publications, patents and patent applications mentioned in this specification are incorporated herein by reference to the extent that each individual publication, patent or patent application is specifically and individually indicated to be incorporated herein by reference. Attached Figure Description

[0016] The novel features of this disclosure are set forth in the appended claims. A better understanding of the features and advantages of this disclosure will be obtained by referring to the following detailed description and accompanying drawings, which illustrate embodiments in which the principles of this disclosure are utilized, in which:

[0017] Figure 1A The illustration shows a schematic diagram of an ultrasonic transducer element in emission mode according to some embodiments.

[0018] Figure 1B The illustration shows a schematic diagram of an ultrasonic transducer element in receiving mode according to some embodiments.

[0019] Figure 2A The illustration shows a cross-sectional view of a transducer element of an ultrasonic transducer according to some embodiments.

[0020] Figure 2B The illustration shows a top view of the transducer element of an ultrasonic transducer according to some embodiments.

[0021] Figure 3A The illustration shows a schematic top view of an ultrasonic transducer comprising multiple transducer elements according to some embodiments.

[0022] Figure 3B These are images of ultrasonic transducers on a base according to some embodiments.

[0023] Figure 4A These are images of multiple ultrasonic transducers on a chip according to some implementation methods.

[0024] Figure 4B These are images of multiple ultrasonic transducers after separation from a wafer, according to some implementation methods.

[0025] Figure 5A , Figure 5B , Figure 5C and Figure 5D The illustration shows a method for manufacturing a cMUT element according to some embodiments.

[0026] Figure 6A The illustration shows a side cross-sectional view of an otoscope arranged inside the ear according to some embodiments.

[0027] Figure 6B The illustration shows a frontal cross-sectional view of an otoscope according to some embodiments of the present disclosure.

[0028] Figure 7A The illustration shows a side cross-sectional view of a peephole according to some embodiments.

[0029] Figure 7B The illustration shows a front cross-sectional view of a peephole tip according to some embodiments.

[0030] Figure 8A and Figure 8B An example data trace according to some embodiments is shown, which illustrates a false-color contour plot in response to membrane motion during disturbance.

[0031] Figure 9A and Figure 9B Example pressure and displacement versus time curves according to some embodiments are shown, which correspond to the values ​​at different times. Figure 8A and Figure 8B The perturbation applied in the example.

[0032] Figure 10A , Figure 10B , Figure 10C and Figure 10D An example graph is shown illustrating membrane migration measurements in the presence of four different viscosities, according to some embodiments.

[0033] Figure 11A and Figure 11B A top view schematic diagram of an example working surface design of a tested transducer element according to some embodiments is shown.

[0034] Figure 12A and Figure 12B A layout table of example ultrasonic transducer configurations tested according to some implementation methods is shown.

[0035] Figure 13A , Figure 13B and Figure 13C A schematic diagram of an ultrasonic transducer configuration for testing each diameter transducer element is shown according to some embodiments.

[0036] Figure 14A , Figure 14B , Figure 14C , Figure 14D , Figure 14E and Figure 14F The diagram shows phase and impedance versus frequency curves for various ultrasonic transducers tested according to some embodiments.

[0037] Figure 15A and Figure 15B Three-dimensional and two-dimensional plots of normalized signal amplitude versus time and ultrasonic transducer size using laser vibrometers are shown, according to some embodiments.

[0038] Figure 16A and Figure 16B Contour plots of beam spread and ultrasonic loss for a set of operable ultrasonic transducers according to some embodiments are shown.

[0039] Figure 17A graph showing the signal-to-noise ratio versus distance for a set of operable ultrasonic transducers according to some embodiments is shown.

[0040] Figure 18 A schematic diagram of an ultrasonic transducer system including a digital processing device and a user-visible display according to some embodiments is shown. Detailed Implementation

[0041] Embodiments of this disclosure provide an ultrasonic transducer. An example ultrasonic transducer may include multiple capacitive ultrasonic transducer elements and a base, wherein the multiple capacitive ultrasonic transducers are mounted on the base. The capacitive ultrasonic transducer elements may be multiple capacitive micromechanical ultrasonic transducer (cMUT) elements. The cMUT may be formed as an ultrasonic transducer configured to guide ultrasonic energy through air.

[0042] Each capacitive ultrasonic transducer element and the ultrasonic transducer can be specifically configured to achieve selected desired performance characteristics. For example, the base may be small. In some cases, the base may have a maximum size, its size and shape adjusted for placement within the external auditory canal. Multiple capacitive ultrasonic elements, including the transducer, can be mounted on the base. The angular extension of the main lobe of the ultrasonic transducer within the gaseous medium can have a value greater than 15 degrees. Furthermore, the emitted ultrasound can have an attenuation loss greater than 10 dB through the gaseous medium, measured along the main transmission axis of the ultrasonic transducer at a distance of 12.5 mm to 25 mm. The ultrasonic transducer may be particularly useful for characterizing the fluid behind the eardrum for the diagnosis of otitis media.

[0043] In some implementations, an ultrasonic transducer measures the dynamic displacement characteristics of a membrane or surface in response to an aerodynamic challenge to the membrane or a surface adjacent to the membrane. The ultrasonic transducer sends and receives ultrasonic energy to and from the surface or membrane to be characterized via a medium such as air. Therefore, the ultrasonic energy can be sufficiently strong to include a plane wave having a spatial range matching the material to be characterized, and / or can include sufficient phase stability across the spatial range of the plane wave to measure the reflected phase to be measured.

[0044] Other design considerations may include size. For example, the base may be small. For instance, the base may be small enough to be positioned within a body cavity, such as the ear canal. The base may be mounted within a trocar or other delivery device for placement within a body cavity. In some examples, multiple transducers mounted on the base are small enough to be positioned within the ear canal. In some examples, the base has a maximum size of less than 10 millimeters (mm), 3 mm, 1 mm, or smaller. In addition to small size, the ultrasonic transducers may be configured to guide an ultrasonic beam through a gas medium with appropriate angular beam spread, attenuation, and / or coherence loss.

[0045] In one example, a material can be characterized by applying a challenging displacement force, such as by blowing air simultaneously with measuring the reflected ultrasonic signal from the material. The material can be a membrane. The material can be the material beneath the membrane. In some cases, the membrane can transparently provide a physical barrier to the material to be characterized without significantly altering the properties of the material opposite the membrane, as seen with an ultrasonic transducer.

[0046] Transducers, transducer elements, and methods of using and manufacturing thereof may be used in combination with methods for characterizing tough films, surfaces, and subsurfaces, as described, for example, in commonly owned U.S. Patent Publication 2018 / 0310917 and U.S. Patent Publication 2017 / 0014053, each of which is incorporated herein by reference in its entirety.

[0047] Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the scope of the invention and the described embodiments. However, the invention is optionally practiced without these specific details. In other instances, well-known methods, steps, components, and circuits have not been described in detail to avoid unnecessarily obscuring aspects of the embodiments.

[0048] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the claims. As used in the description of the embodiments and the appended claims, unless expressly stated otherwise, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well. It should also be understood that the term “and / or” as used herein refers to and covers any and all possible combinations of one or more of the associated listed items. It will be further understood that when the terms “comprising” and / or “including” are used in this specification, they specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0049] As used herein, the term "if" may optionally be interpreted as meaning "when," "after," or "in response to a measurement," or "according to a measurement," or "in response to a detection," when the prerequisite is true, depending on the context. Similarly, the phrases "if it is determined [that the prerequisite is true]," "if [that the prerequisite is true]," or "when [that the prerequisite is true]" may optionally be interpreted as meaning "after," "in response to," "according to," "according to," or "in response to a detection," when the prerequisite condition is true, depending on the context.

[0050] ultrasonic transducer

[0051] Figure 1AThe illustration shows a schematic diagram of an ultrasonic transducer in emission mode according to some embodiments. In some cases, the ultrasonic transducer may be a capacitive micromechanical ultrasonic transducer (cMUT). Unlike piezoelectric transducers, cMUTs can be driven by capacitance changes between the transducer's working surface (e.g., a membrane, plate, etc.) and a substrate. The emission waveform provided to the transducer element by a digital processing device can be converted into an ultrasonic signal by oscillations of the working surface. The working surface may be electrically connected to a first electrode. The substrate may be electrically connected to a second electrode. The transducer element may include a drive circuit that can control the capacitance of the transducer element, for example by applying a voltage or current between the first and second electrodes. The applied voltage may include a voltage offset from system ground and a drive signal. The drive signal may include a voltage that varies over time according to the drive waveform. The drive waveform may be an analog output from a digital-to-analog converter in response to a digital signal from a digital processing device as described elsewhere herein. The drive circuit may include additional components, such as amplifiers, filters, mixers, etc., not shown. These additional components may themselves be analog or digital elements. In some implementations, digital components such as digital amplifiers, digital filters, or digital mixers can be implemented by digital processing devices as described herein.

[0052] Figure 1B The illustration shows a schematic diagram of an ultrasonic transducer in receiving mode according to some embodiments. In some embodiments, Figure 1B The implementation methods shown are the same as Figure 1A The ultrasonic transducer is the same. In other embodiments, the individual transducer elements may be specifically configured as receiving elements and transmitting elements. Figure 1B The ultrasonic transducer may include and Figure 1ASimilar elements to transducers. For example, an ultrasonic transducer can be a capacitive micromechanical ultrasonic transducer (cMUT). The transducer can be driven by capacitance changes between the transducer's working surface (e.g., a membrane, plate, etc.) and a substrate. The received ultrasonic signal can be detected by the transducer element and provided to a digital processing device. The received signal can be converted into an electrical signal by oscillation of the working surface, which changes the capacitance of the transducer element. The working surface can be electrically connected to a first electrode. The substrate can be electrically connected to a second electrode. The transducer element can include a drive circuit that can detect capacitance changes in the transducer element, for example, by detecting changes in voltage or current between the first and second electrodes. The changing voltage or current can direct an analog-to-digital converter to generate a digital signal, which can be received by a digital processing device described elsewhere herein. The drive circuit can include additional components not shown, such as amplifiers, filters, mixers, etc. These additional components can themselves be analog or digital elements. In some embodiments, digital components such as digital amplifiers, digital filters, or digital mixers can be implemented by the digital processing device described herein.

[0053] Figure 2A The illustration shows a cross-sectional view of a transducer element of a cMUT according to some embodiments. The illustrated embodiments may be... Figure 1A or Figure 1B The transducer element shown is an embodiment, variant, or example. The transducer element 100 may include a substrate 102, a first isolation layer 104, a bottom electrode 106, a second isolation layer 108, a plate or top electrode 110, a pad contact 112, an oxide layer 114, and a hydrophobic protective layer 116.

[0054] In some cases, the substrate can be silicon, gallium nitride, silicon carbide, etc. The substrate can be single-crystal or amorphous. The substrate can be single-sided polished silicon. The substrate can be double-sided polished silicon. The substrate can be glass. The substrate can have a range of thicknesses. The substrate can have a thickness between 200 micrometers and 5000 micrometers. The substrate can have a thickness between 650 micrometers and 700 micrometers. The substrate thickness can be approximately 675 micrometers. The substrate can be part of a wafer or carrier. The substrate can be part of a substrate.

[0055] The substrate can be electrically isolated from the working surface of the drive circuit or transducer element. The substrate can be electrically isolated via a first isolation layer. The first isolation layer may include silicon dioxide. The first isolation layer can have a certain thickness. The first isolation layer can have a thickness in the range of 990 to 1100 nanometers (nm). The thickness of the first isolation layer can be approximately 1000 nm.

[0056] The transducer element may include a bottom electrode. The bottom electrode may be conductive. The bottom electrode may include titanium and aluminum. The bottom electrode may include TiAl or similar materials. The bottom electrode may have a range of thicknesses. The bottom electrode may have a thickness in the range between 180 and 220 nm. The bottom electrode may have a thickness of approximately 200 nm. The bottom electrode may be electrically isolated from the substrate and the working surface of the transducer. The bottom electrode may be electrically connected to the drive circuitry via exposed electrical contacts (e.g., “pads”).

[0057] The transducer element may include a second isolation layer that isolates the bottom electrode from the working surface of the transducer element. The second isolation layer may further isolate the top electrode from the bottom electrode and the substrate. The second isolation layer may include silicon dioxide or a similar insulating material. The second isolation layer may include a plasma-enhanced oxide layer. The second isolation layer may have a range of thicknesses. The second isolation layer may have a thickness in the range of 180 to 220 nm. The second isolation layer may have a thickness of approximately 200 nm.

[0058] The transducer element may include a plate. The plate may be conductive. If the plate is conductive, it may be a top electrode. The plate may include a top electrode. The plate may be electrically connected to the top electrode. The plate may include the working surface of the transducer, which may be referred to as a film or plate. The top electrode may be electrically connected to the drive circuitry via electrical contacts (e.g., "pads"). The plate may have a range of thicknesses. The plate may have a thickness in the range between 450 and 550 nm. The plate may have a thickness of approximately 500 nm. The plate may include titanium and aluminum. The plate may be made of TiAl or similar materials.

[0059] The plate layer can be temporarily separated from the second isolation layer by a sacrificial layer. The thickness of the sacrificial layer can be related to the height of the cavity between the working surface and the second sacrificial layer. The cavity can be formed with a certain range of heights. In some cases, the cavity height can be greater than about 50 nm, 100 nm, 200 nm, 500 nm, 1000 nm, 2000 nm, or any height within the range defined by any two of the foregoing values. In some cases, the average cavity height can be less than about 1500 nm, less than about 1000 nm, or even smaller. In some cases, the cavity height can be about 350 nm, about 850 nm, or about 1100 nm.

[0060] The exposed surface of the cMUT can be coated with silicon dioxide or other suitable oxides with a thickness of 2 to 100 nanometers (nm). The exposed surface of the cMUT can be coated with silicon dioxide or other oxides with a thickness greater than 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50. Other suitable oxides of 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100 nm. The exposed surface of the cMUT can be coated with silica or have a thickness of less than 100, 99, 98, 97, 96, 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55. Other suitable oxides of 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, or 2 nm.

[0061] The exposed surface of the cMUT can be coated with a hydrophobic material with a thickness of 1 to 200 nm, such as polytetrafluoroethylene or perfluorodecyltrichlorosilane. The exposed surface of the cMUT can also be coated with a material thicker than 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 5 8, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 11 3, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, Hydrophobic materials with wavelengths of 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, or 200 nm.The exposed surface of cMUT can be coated with coatings of thickness less than 200, 199, 198, 197, 196, 195, 194, 193, 192, 191, 190, 189, 188, 187, 186, 185, 184, 183, 182, 181, 180, 179, 178, 177, 176, 175, 174, 173, 172, 171, 170, 169, 168, 167, 166, 165, 164, 163, 162, 161, 1 60, 159, 158, 157, 156, 155, 154, 153, 152, 151, 150, 149, 148, 147, 146, 145, 144, 143, 142, 141, 140, 139, 138, 137, 136, 135, 134, 133, 132, 131, 130, 129, 128, 127, 126, 125, 124, 123, 122, 121, 120, 119, 118, 117, 116 115, 114, 113, 112, 111, 110, 109, 108, 107, 106, 105, 104, 103, 102, 101, 100, 99, 98, 97, 96, 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, Hydrophobic materials of 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3 or 2 nm.

[0062] Figure 2B The illustration shows a top view of a transducer element according to some embodiments. In some cases, the plate may include a circular working surface. The working surface may be circular with a diameter variation within 10%. In some cases, the working surface is polygonal. For example, the working surface may be hexagonal, octagonal, decagonal, dodecagonal, etc. The working surface may have a range of diameters. In some cases, the element has a working surface with a diameter between 30 micrometers and 100 micrometers. The maximum dimension across the working surface of the transducer may be less than about 10 micrometers, about 20 micrometers, about 50 micrometers, about 100 micrometers, about 200 micrometers, about 500 micrometers, or within the range defined by any two of the foregoing values.

[0063] The plate may include one or more holes or openings within the working surface of the transducer element. Release holes facilitate movement of the working surface. Release holes can alter the motion characteristics of the working surface, such as frequency, operating voltage, operating impedance, operating capacitance, etc. In some cases, the element includes multiple openings in the working surface. In some cases, there may be at least about 2 holes, about 5 holes, about 10 holes, about 20 holes, about 50 holes, about 100 holes, or any number of holes within the range defined by any two of the foregoing values. In some cases, each capacitive ultrasonic transducer element may have at least three release holes. In the illustrated embodiment, the transducer element has six circular holes spaced at equal angles on a 40-micrometer circle centered on the working surface of the transducer element.

[0064] The holes can be arranged in a regular geometric pattern within the transducer surface or can be irregularly spaced. In some cases, the holes are arranged in a circular pattern. In some cases, the openings are arranged in a circular pattern with a diameter greater than 5 micrometers. The holes can be spaced at equal angles within a circle with a diameter less than about 5 micrometers, 10 micrometers, 20 micrometers, 50 micrometers, 100 micrometers, 200 micrometers, or any diameter within the range defined by any two of the foregoing values. The holes in the working surface can be circular or can be cut into flaps. In some cases, the holes are cut into slits. In some cases, the openings are circular. In some cases, the openings are curved.

[0065] The slit-shaped opening can have a slit width. The flap can have a slit width and a spring length. The slit width can be less than about 1 micrometer, about 2 micrometers, about 5 micrometers, about 10 micrometers, about 20 micrometers, about 50 micrometers, about 100 micrometers, or any length within the range defined by any two of the foregoing values. The spring length can be less than about 0.2 micrometers, 0.5 micrometers, 1 micrometer, 2 micrometers, 5 micrometers, 10 micrometers, 20 micrometers, or any length within the range defined by any two of the foregoing values. In some cases, the opening can be formed as a release slit having a slit width of at least 0.4 micrometers and a spring length of at least 2 micrometers. In some cases, there are no etched holes in the working surface of the device. The size, shape, and position of the holes in the working surface of the transducer element can adjust the bandwidth and sensitivity of the transducer element.

[0066] Figure 3AA schematic top view of an ultrasonic transducer including multiple transducer elements 301 according to some embodiments is illustrated. The multiple transducer elements 301 may be arranged together to form an ultrasonic transducer 300. The ultrasonic transducer 300 may include electrical connections 305 that can provide controllable drive current or voltage to the top electrode 303 and bottom electrode 304 of each transducer element. The ultrasonic transducer may include multiple pads that form multiple electrical contacts. As shown, the top electrode of each transducer element may be electrically connected to one or more top drive pads. As shown, the bottom electrode of each transducer element may be electrically connected to one or more bottom drive pads. As discussed elsewhere herein, the bottom drive pads and top drive pads may be connected to control circuitry, such as a digital-to-analog converter, a digital processing device, etc.

[0067] An ultrasonic transducer may include between 10 and 1000 transducer elements. In some cases, an ultrasonic transducer includes between 50 and 200 transducer elements. An ultrasonic transducer may include more than about 10, about 20, about 50, about 100, about 200, about 500, or more transducer elements. An ultrasonic transducer may include about 80 transducer elements. In some cases, an ultrasonic transducer includes at least 20 capacitive ultrasonic transducer elements.

[0068] Multiple ultrasonic transducer elements can be arranged in a pattern to form an ultrasonic transducer. This pattern can be regular or irregular. The transducer elements can be arranged in a hexagonal close-packed arrangement. The transducer elements can be arranged in a rectangular close-packed arrangement. The transducer elements can be arranged in a non-geometric pattern. The elements of the ultrasonic transducer can be arranged within a circular region with a diameter equal to the edge length. The elements of the ultrasonic transducer can be arranged within a rectangular region with the longest side equal to the edge length. The ultrasonic transducer can have a maximum size spanning the surface of the ultrasonic transducer. The maximum size can be the farthest distance between the two farthest working edges of the two farthest transducers in the arrangement. The ultrasonic transducer can include a maximum size that can be less than about 1 mm, about 2 mm, about 5 mm, etc. The maximum size can provide a lower threshold on the minimum surface size of the base. Therefore, the maximum size should be smaller than the diameter of the body cavity in which the transducer can be placed, such as the ear canal.

[0069] The elements of an ultrasonic transducer can be electrically connected to each other via one or more conductors that connect the element to a second element. In some cases, each top electrode of each element can be connected to the top electrodes of the ultrasonic transducer. In some cases, each bottom electrode of each element can be connected to the bottom electrodes of the ultrasonic transducer. The top electrodes of the ultrasonic transducer can have a single electrical contact, and the bottom electrodes can have a single electrical contact. There can be two contacts for the top electrodes and two contacts for the bottom electrodes for a common wiring. In other cases, the elements can be electrically controlled independently or in groups. Each element or group of elements can be controlled by its own contacts. In one example, all transducer elements are typically controlled by a single drive waveform.

[0070] With the top and bottom electrodes connected together, all or most of the transducer elements can operate in series. For example, when a voltage is applied, all or most of the transducer elements can move synchronously. Elements on the outer edge of the transducer may exhibit phase shift (e.g., they may deflect earlier or later than elements at the center of the transducer). In some cases, individual elements may exhibit phase shift due to irregularities in the manufacturing process. Transducers whose elements operate closer to operating in the same phase may exhibit improved performance than transducers whose elements operate further away from the same phase. Similarly, transducers whose elements deflect at more similar amplitudes may exhibit improved performance.

[0071] Figure 3B This is an image of an ultrasonic transducer 300 on a base 306 according to some embodiments. The base 306 may include a substrate described elsewhere herein. In some embodiments, the substrate is disposed on a bracket material, which may be part of the base. The base 306 may allow the ultrasonic transducer to be mounted on the apparatus of this disclosure. For example, the base 306 may be mounted on the tip of a sight 307 described elsewhere herein. The base 306 may include electrical connections, such as wiring necessary for conducting electrical signals from the ultrasonic transducer to a digital processing device, VIA (vertical interconnect access), etc. The base 306 may include electrical connections, such as wiring necessary for conducting electrical signals to an analog front end, VIA, etc., which both drives the ultrasonic transducer to produce sound output and listens to the ultrasonic transducer to capture echoes from objects / interfaces in the beam path of the transducer. The base 306 may protect the ultrasonic transducer. The base 306 may reinforce and / or provide additional support for the substrate of the ultrasonic transducer. The base 306 may include part of a wafer on which the ultrasonic transducer is fabricated.

[0072] This document discloses the provided transducer elements and methods for manufacturing ultrasonic transducers. In some examples, multiple ultrasonic transducers can be manufactured simultaneously, each including multiple transducer elements. Figure 4AThese are images of multiple cMUT400s on a wafer 401 according to some embodiments. The ultrasonic transducer can be separated from the wafer individually by cutting (e.g., slicing) the wafer or by peeling. Figure 4B These are images of multiple cMUTs 400 after separation from wafer 401, according to some embodiments. As shown, the multiple ultrasonic transducers may also include a portion of the wafer or sacrificial material disposed on wafer 402, which can facilitate transducer mounting. All or part of substrate 403 may be fabricated on the wafer.

[0073] Figure 5A , Figure 5B , Figure 5C and Figure 5DThe illustration depicts a method 500 for manufacturing one or more cMUT elements according to some embodiments. At operation 502, a silicon wafer 503 may be provided. The silicon wafer 503 may be cleaned. The silicon wafer 503 may include a substrate as disclosed elsewhere herein. At operation 504, layers of a first insulating material 501 and a bottom electrode material 507 may be deposited, respectively. A protective plate 505 may be placed on a portion of the bottom electrode material 507. A photolithography of the bottom electrode material 507 is shown. At operation 506, a second electrode material may be etched and a second insulating material 509 may be deposited on the surface. At operation 508, a first sacrificial layer 511 may be deposited. At operation 510, a photolithography of the sacrificial layer 511 is shown. A protective layer may be placed on a portion of the sacrificial layer. At operation 512, a portion of the sacrificial layer may be etched, thereby initiating the structure of the sacrificial layer 511. At operation 514, a second sacrificial layer 513 may be added to the first sacrificial layer. The second layer may thereby form inclined sidewalls. At operation 516, a photolithography of the second sacrificial layer is shown. A protective layer 515 can be placed on a portion of the second sacrificial layer. At operation 518, a portion of the second sacrificial layer 513 can be structured by plasma etching. At operation 520, a substrate 517 can be deposited. At operation 522, photolithography for the substrate is shown. A protective layer 519 can be placed on a portion of the substrate. At operation 524, a portion of the substrate can be etched to construct substrate 517. At operation 526, photolithography for the substrate is shown. A protective mask 521 can be placed on the isolation material layer 509 and substrate 517. Etching to open contact pads 523 by etching the isolation material layer 509 is also shown. At operation 528, deposition of contact pad material 525 can be performed. At operation 530, photolithography of the contact pads 523 is shown. A protective layer 527 can be applied to the contact pads 523. At operation 532, wet etching of excess contact material is shown. At operation 534, photolithography and plasma etching of the release hole 531 using a protective mask 529 are shown. At operation 536, photolithography and etching of the cut channel 533 using a protective mask 535 are shown. At operation 538, which may be optional, a photolithographic overlay 537 of the cut channel 533 is shown. At operation 540, which may be optional, xenon difluoride etching of the second sacrificial layer 513 is shown. At operation 542, which may be optional, a thin oxide layer 541 is applied to all exposed surfaces using an atomic layer deposition (ALD) process. At operation 544, a physical vapor deposition process of polytetrafluoroethylene (PTFE) 543 or an ALD of perfluorodecyltrichlorosilane (FDTS) is applied to all exposed surfaces. The transducer element may be cut along the cut channel 533.

[0074] Operating parameters

[0075] The ultrasonic transducers described herein typically have operating parameters that allow them to transmit and receive ultrasonic energy to and from the material or surface to be characterized via a gaseous medium such as air. Therefore, the ultrasonic energy delivered to the material or surface to be characterized can be sufficiently strong, comprising a plane wave with a spatial range to match the material being characterized, and / or can include sufficient phase stability across the spatial range of the plane wave for measuring the reflected phase to be measured. Another consideration may be size. Each of intensity, spatial coherence, divergence, and phase can be affected by making the device smaller.

[0076] An ultrasonic transducer can be electrically connected to a digital processing device as described herein. The digital processing device can control the transducer elements and various aspects of the ultrasonic transducer as disclosed herein. For example, a system may include a digital processing device, an analog-to-digital converter, an analog “front end,” and a transducer. Sometimes, the system may also include a mechanical layer between the transducer and the object to be ultrasonically interrogated, which constitutes, for example, a quarter-wavelength matching layer. The digital processing device can provide a driving waveform for the ultrasonic transducer. For example, the digital processing device can provide a driving waveform for an excitation device. For example, the digital processing device can receive from the transducer a waveform corresponding to a reflected ultrasonic signal from the device.

[0077] Communication between the transducer and the digital processing unit can be mediated by a digital-to-analog converter (DAC). The ultrasonic transducer can have an average capacitance and resistance voltage sufficient to couple to the DAC. For example, the capacitance of the ultrasonic transducer can be between 2.5 picofarads (pF) and 10.0 pF. Alternatively, the capacitance of the ultrasonic transducer can be less than 50 pF, less than 20 pF, less than 10 pF, less than 5 pF, less than 2 pF, less than 1 pF, or any capacitance within the range given by any two of the foregoing values.

[0078] For example, the resistance of an ultrasonic transducer between 0 and 10 kHz can be between 1 and 150 megohms (MΩ). For example, the resistance of an ultrasonic transducer can be less than 10 MΩ, less than 5 MΩ, less than 2 MΩ, less than 1 MΩ, less than 0.5 MΩ, less than 0.2 MΩ, less than 0.1 MΩ, less than 0.05 MΩ, less than 0.02 MΩ, less than 0.01 MΩ, or any resistance within the range given by any two of the foregoing values.

[0079] The drive waveform can be electrically transmitted from the DAC to the ultrasonic transducer via the transducer's contact pads. When transducer elements are commonly connected to the same pads, the drive waveform can be transmitted via the pads to each top or bottom electrode of each element. Each transducer element can respond to the drive waveform based on its own physical characteristics and the fidelity of the waveform transmitted to the transducer. Each element can emit an ultrasonic signal in response to the drive waveform. The transducer can emit an ultrasonic signal corresponding to the sum of the emitted ultrasonic signals of the elements.

[0080] Applying a voltage to each ultrasonic transducer element causes the working surface of the transducer element to deflect. In some cases, the bias voltage is maintained. In other cases, the bias voltage may not exceed the pull-in voltage. At sufficient voltage, the working surface may deflect to the bottom surface of the transducer cavity, which could damage the transducer. The ultrasonic waveform can be generated by a second signal, which is an oscillating voltage at the carrier frequency and can increase the bias voltage. If the duty cycle is low, the oscillating voltage, together with the bias voltage, may exceed the maximum pull-in voltage in some cases without any consequences. In some cases, a large oscillating voltage in a single pole can be used. A single-pole oscillating voltage with a bias voltage may result in a lower net voltage.

[0081] The voltage can be within the operating range that the drive circuit of the ultrasonic transducer can transmit. For example, the ultrasonic transducer can have a pull-in voltage of less than about 60V, 50V, or even lower than 80%. For example, the ultrasonic transducer can have a pull-in voltage of less than about 45V.

[0082] The degree of deflection of each element per unit voltage can be controlled by factors such as the material of the substrate, the thickness of the substrate, the radius of the substrate, the holes in the substrate, and the height of the gap below the substrate. The response time between the applied voltage and the deflection may be affected by factors such as the distance between the transducer and the DAC, and the frequency bandwidth of the transducer.

[0083] The operating frequency of a cMUT can vary with the drive circuitry; however, the operable range of the operating frequency may be determined by the geometry and composition of the transducer elements themselves. For example, the operating frequency may be affected by the dimensions of the transducer element's working surface, the geometry of the release orifice, the materials used to form the individual elements, etc. Each transducer element may include a resonant frequency at which the transducer is more sensitive. Each transducer element may also be sensitive within a certain frequency range. The operable frequency range of an ultrasonic transducer can be referred to as its bandwidth.

[0084] The bandwidth of an ultrasonic transducer can be related to its response time to an applied driving voltage. For example, if the applied voltage is a square wave excitation, a transducer with a larger bandwidth can better reproduce the higher frequency components of the square wave, thus producing a more square wave transmitted waveform. The bandwidth of an ultrasonic transducer can be an important factor in constructing an air-coupled cMUT. In one example, if the spread of frequency components is too large, beat frequency oscillations can cause tailing of the received signal. In one example, the ultrasonic transducer has a frequency bandwidth of + or -5% of the center frequency at full width at half maximum (FWHM). In some cases, the bandwidth of the transducer can be characterized by frequency sweep measurements. In one example, a portion of the bandwidth of the ultrasonic transducer can be greater than 10%. The portion of the bandwidth of an ultrasonic transducer can be related to the range of frequencies that can be generated by the transducer. A transducer with a higher bandwidth can be tuned over a larger frequency band. Phase characteristics can set functional upper and lower limits for the transducer frequency for a particular transducer configuration. In some cases, high ultrasonic frequencies may be associated with lower beam spread. The transducers disclosed herein can have center frequencies between 1 MHz and 3 MHz. The transducer disclosed herein can have a center frequency greater than 1 MHz. The transducer disclosed herein can have a center frequency greater than 2 MHz.

[0085] A functional transducer can have sufficient reflection intensity at the transducer to measure the oscillation of the tympanic membrane while remaining below a threshold that would damage the tympanic membrane. In other cases, a functional transducer may have sufficient reflection intensity at the transducer to measure the oscillation of the surface being characterized while remaining below a threshold that would damage that surface. Some media or reflecting surfaces themselves may be particularly absorptive. For example, significant ultrasonic absorption (e.g., in tissue and air) may occur when there is a significant impedance mismatch between the reflecting surface and the propagation medium. For example, the intensity of the ultrasonic beam may attenuate due to diffraction loss. Diffraction loss can be reduced by improving the phase coherence in the emitted ultrasonic beam.

[0086] Furthermore, the intensity of the ultrasonic beam can be customized for the application. For example, the ultrasonic intensity must be low enough to avoid posing a safety hazard to the tympanic membrane or hearing mechanism. Conversely, the ultrasonic intensity must be high enough to allow measurement of the reflected ultrasonic signal. In one example, the ultrasonic transducer has a projected peak sound pressure level of approximately 40 Pa or less, or 20 Pa or less, measured along the axis of the main lobe of the ultrasonic beam at a distance of 15 mm from the transducer. The ultrasonic transducer can have a peak sound pressure level of approximately 40 Pa to 250 Pa measured along the axis of the main lobe of the ultrasonic beam at a distance of 25 mm from the transducer. The ultrasonic transducer can have a peak sound pressure level of approximately 20 Pa to 120 Pa measured along the axis of the main lobe of the ultrasonic beam at a distance of 12.5 mm from the transducer.

[0087] Operating an ultrasonic transducer in an absorbing medium may be advantageous. For example, the transducer of this disclosure may be operable when the diffraction loss of the target along the axis of the main lobe of the ultrasonic beam at a distance of 12.5 mm to 25 mm from the transducer can be between 20 and 40 dB (round trip). In one example, the ultrasonic transducer has an attenuation loss (round trip) of greater than 45 dB in a gaseous medium, measured along the axis of the main lobe of the ultrasonic beam at a distance of 12.5 mm to 25 mm from the transducer.

[0088] It may be advantageous for the ultrasonic beam to be sufficiently divergent to illuminate the target. It may also be advantageous for the ultrasonic transducer to be narrow enough (directional) to avoid attenuation losses. In one example, the ultrasonic transducer can produce an angular beam that propagates through a gaseous medium of less than 15 degrees. In one example, the ultrasonic transducer can produce an angular beam spread between 10 and 20 degrees within a bandwidth of 1.2 to 1.8 MHz and with transducer edge lengths between 0.6 and 1.0 mm. The angular beam spread can be affected by the phase characteristics of the ultrasonic transducer elements relative to each other. For example, diffraction losses may occur when one or more transducer elements are out of phase or partially out of phase with respect to the average value of all elements of the transducer.

[0089] Having a sufficient signal-to-noise ratio (SNR) to detect the phase of the reflected waveform from the target tissue is advantageous for an ultrasonic transducer. The SNR can decrease with increasing ultrasonic wave travel distance. For example, the detected signal may decrease due to losses through a gaseous transmission medium. This decrease can be due to diffraction, absorption, etc. Similarly, if the ultrasonic beam is divergent, the detected reflected ultrasound can be similarly reduced. The device disclosed herein exhibits an SNR greater than 30 dB (round-trip), measured at a target distance of 12.5 mm to 25 mm along the transducer's main transmission axis.

[0090] Surface characterization

[0091] The transducers described herein can be used to characterize surfaces and materials adjacent to those surfaces. The transducers can be configured to operate in multiple modes, such as any of the following ultrasound modes: Mode A, Mode B, Mode M, or Doppler mode. Mode A is the simplest type of ultrasound. The transducer scans along the target line and plots the echo as a function of depth on a screen. Mode B requires a linear array of transducers that scan through a plane of the target, which can be viewed as a two-dimensional image. In some embodiments, multiple transducer devices can be provided and arranged in a linear array for Mode B operation. Mode M requires a rapid sequence of Mode A or Mode B scans organized graphically to allow the user to view and measure the range of motion of the target. Doppler mode utilizes the Doppler effect to measure and visualize fluid flow. By calculating the frequency shift of the target volume, velocity and direction can then be determined and visualized graphically using spectral Doppler as an image using directional or non-directional power Doppler. In some embodiments, one or more transducer devices described herein can be placed in Doppler mode near a moving object or fluid (e.g., a blood vessel containing circulating blood) to determine motion-related features and / or properties.

[0092] Specifically referring to surface characterization, a low-frequency excitation source can generate motion on the surface or membrane within intervals. These intervals can correspond to the acoustic waves transmitted to the surface or membrane by an ultrasonic transmitter. The excitation can be continuous, pulsed, etc. Ultrasonic waves reflected from the surface can be received at a transducer. This transducer can be the same one that generated the incident acoustic waves. The displacement of the surface or membrane can be related to the phase change of the received signal (compared to the transmitted signal). The motion of the membrane can affect the phase change. This displacement can vary over time. Analysis of the temporal displacement of the surface or membrane can be used to determine the mechanical properties of the surface or membrane or the underlying material at the distal end of the surface, such as by measuring the phase shift of reflected ultrasound in response to a pneumatic excitation coupled to the surface or membrane. This information can be combined with temporal displacement measurements from templates of other membrane responses to create comparisons. This information can be combined with other metrics related to the response delay and amplitude of the surface or membrane to the low-frequency excitation source. The measured mechanical properties can include non-contact measurements of mechanical properties that can determine the fluid beneath the surface or membrane.

[0093] In some implementations, the elasticity of the surface can be measured. The phase and / or amplitude of the reflected ultrasound can be analyzed to generate an elasticity metric. An elasticity measurement can characterize a series of measurements in response to an applied excitation. The elasticity metric can be derived from the surface's response and can provide one or more indications of several different phenomena. For example, an elasticity metric can indicate whether a surface adjacent to a membrane has a gaseous boundary (in which case the reflection is from the membrane itself) or a fluid boundary (in which case the reflection is from both the membrane and the fluid adjacent to the membrane). In examples, for characterizing the fluid behind the membrane fluid boundary, the elasticity metric can indicate the degree or characteristic of the fluid. In some examples, the elasticity metric can be used to measure the characteristics of elastic fluids with or without response hysteresis. In fluids with hysteretic responses, the fluid may exhibit a shift in displacement response or "memory," such that the response behavior in one direction is similar to the response behavior in the opposite direction, but this only occurs after a specific displacement distance has been traveled. For hysteretic responses, it may be necessary to characterize the linear behavior of the response after a specific measured displacement associated with the system hysteresis. The fluid elasticity metric can be determined based on the characteristic response of the surface or membrane to surface excitation and the ultrasonic characterization of the reflection. The surface response to low-frequency stimuli may also exhibit asymmetry. If the fluid beneath the membrane exceeds its normal volume, the membrane may be in an expanded state and less likely to move toward the transducer than toward it. Conversely, if the fluid beneath the membrane is below its normal volume, the membrane may be in a retracted state and less likely to move away from the transducer than toward it.

[0094] In some implementations, surface deflection can be estimated. For example, the estimate of surface deflection can be derived from a measurement of velocity, acceleration, or any other relevant metric relating deflection to time. For instance, displacement of the surface will cause a shortening of the path from the transducer to the surface, and the reflected signal returning from the surface to the transducer will show a phase shift. Therefore, the phase shift of the reflected ultrasound relative to the excitation provides information about the amount of deflection. Using the estimate of the force applied by the excitation, an elastic estimate of the membrane can be estimated.

[0095] In one example, the excitation is a step or pulse response with a rising edge, a falling edge, or a pulse excitation. The pulse excitation causes an oscillatory deflection of the membrane. The reflected ultrasound can be measured based on the time from excitation to the damping period of the membrane oscillation. In some embodiments, the estimation of elasticity or viscosity can be performed by examining ringing characteristics. For example, ringing characteristics may include at least one of exponential decay time or ringing period interval or frequency, such as decomposing the response into ringing characteristics, for example:

[0096]

[0097] in:

[0098] ϕ(t) is the capture phase of a series of measurements;

[0099] τ is the exponential decay coefficient;

[0100] f is the ringing period frequency; and

[0101] t represents time.

[0102] The damping constant of an oscillator can be related to the energy lost from the membrane to the surrounding environment. In one example, if the membrane is adjacent to a fluid, the fluid can dampen the membrane's oscillations. The viscosity of the fluid can be related to the damping of the oscillator. The ringing period frequency can be related to the restoring constant of the elastic membrane. The restoring constant can be related to the elasticity of the membrane. The restoring constant can be related to the viscosity of the fluid adjacent to the membrane. The lower the viscosity of the fluid adjacent to the membrane, the higher the ringing period frequency can be.

[0103] Each excitation event can induce a new deflection of the membrane. For example, a pulse excitation can pull the membrane in or out for a finite time. For example, a square wave excitation can pull the membrane in or out for a longer time. For example, a sine wave or other more complex excitation can be applied, and the ringing observed at the transducer can be a cross-correlation between the excitation field and the response field.

[0104] application

[0105] Transducers, transducer elements, and their use and manufacturing methods can be used to characterize numerous biological tissues to provide a variety of findings that inform medical diagnosis. Biological tissues may include patient organs. A speculum may be positioned within a body cavity to locate one or more transducers to characterize patient tissues. Once in place, the transducer can operate in any of the modes described herein to characterize patient tissues. Patient organs or body cavities may include, for example: ear canal, muscle, tendon, mouth, tongue, pharynx, esophagus, stomach, intestine, anus, liver, gallbladder, pancreas, nose, larynx, trachea, lung, kidney, bladder, urethra, uterus, vagina, ovary, testis, prostate, heart, arteries, veins, spleen, glands, brain, spinal cord, nerves, etc.

[0106] In the examples, transducers, transducer elements, and their use and manufacturing methods can be used to characterize animal or human organs, such as the ear. For example, the transducer can be mounted on a speculum and positioned within the ear canal. An excitation generator can apply pulsed pressure to the tympanic membrane, the transducer can guide ultrasound to the tympanic membrane, and the reflected ultrasound energy can be measured from the surface of the tympanic membrane. The phase change of the reflected ultrasound during the application of non-contact excitation and / or after the removal of non-contact excitation can indicate elasticity, which may be related to the type of fluid behind the tympanic membrane (e.g., air), indicating a healthy ear as further described herein, clear fluid, indicating a viral infection, or opaque fluid, indicating a bacterial infection.

[0107] In another example, transducers, transducer elements, and methods of use and manufacture thereof can be used to characterize animal or human organs, such as the eye. For example, an excitation generator can apply pulsed pressure to the eye, the transducer can direct ultrasound to the eye, and the reflected ultrasound energy can be measured from the eye surface. The phase change of the reflected ultrasound during the application of non-contact excitation and / or after the removal of non-contact excitation can indicate elasticity that can be correlated with interocular pressure used to measure or diagnose glaucoma.

[0108] In another example, transducers, transducer elements, and methods of use and manufacture thereof can be used to characterize animal or human lungs. For example, audio tones from the chest (e.g., at frequencies of 3 to 20 Hz) can be demodulated from the transducer. The transducer can be integrated into a stethoscope-like device in which the transducer can be moved upwards to the chest during a “tapping test” (auscultation) to identify changes in reflected ultrasound, which can indicate fluid (e.g., mucus or water) in the lungs. In some embodiments, multiple transducers or an array of transducers can be provided and placed or worn on the chest. Phase changes in reflected ultrasound during application can indicate changes in fluid viscosity, which may be associated with lung diseases such as pneumonia, lung cancer, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), etc.

[0109] Transducers, transducer elements, and their use and manufacturing methods can be used, for example, to characterize food. For instance, an excitation generator can apply pulsed pressure to the surface of a food such as a vegetable or fruit, and ultrasonic energy can be applied to the food to measure the time-dependent surface response of the fruit or vegetable to determine elasticity or other physical properties that may be related to the ripeness of the fruit or vegetable. For example, food can be placed in a holder, and the surface can be excited with a gas cloud such as air, the deflection response of which can be used to estimate ripeness or other properties. For example, the excitation can be a gas that can be delivered to the surface of the food at supersonic speeds and / or grazing angles, or one or more foods can be placed in a chamber with variable pressure to measure the low-frequency surface response to pressure, such as the relationship between deflection and pressure. For example, an excitation can be applied to a surface, and the response can be measured on different surfaces of the same article, such as the measurement of propagating surface waves or shear waves traveling through the article being characterized.

[0110] Transducers, transducer elements, and their use and manufacturing methods can be used to characterize industrial processes. For example, the small-sized transducers disclosed herein can be applied to any industrial process where larger transducers, ultrasound, or other modalities (e.g., LIDAR) are prohibited due to their large size. The high resolution achieved by the currently disclosed transducers over short distances (e.g., a range of less than 25-35 mm and a movement of 10 to 20 micrometers (e.g., by Doppler integration)) allows the invention to be applied to a wide range of industrial processes where analysis without physical contact with the analyte is necessary. For example, an excitation generator can apply pulsed pressure to the surface of a manufactured part to determine the consistency of a viscous fluid (e.g., a lubricant), and ultrasonic energy can be applied to the part to measure the time-dependent surface response of the viscous fluid to determine elastic or other physical properties that may be related to the quality of the lubricant. The transducer can be used to measure the thickness of a coating by comparing a painted portion of an object to an unpainted portion. The transducer can be used to measure whether a painted object is dry by comparing a painted object to a similar object that has recently been painted with the same paint. Transducers can be used as part of a manufacturing process to identify objects as part of a counting process for objects being manufactured. Transducers can be used to measure changes in the density or composition of an object by comparing an object that has undergone a process to an object that has undergone a process prior to that process (e.g., cooked food, curing processes, etc.). Other industrial examples can include ranging applications, ultrasonic time-of-flight gas flow meters for metering dynamic gas flow rates, wind speed measurement applications, and a variety of other ultrasonic-based sensing applications.

[0111] Otoscopic device

[0112] Transducers, transducer elements, and their use and manufacturing methods can be used to characterize the tympanic membrane. For example, the membrane can be characterized to determine the condition of the ear, such as acute otitis media (AOM). Characterization of an ear exhibiting AOM can include detecting the presence of effusion and characterizing the effusion type as serous, mucoid, purulent, or one combination of these. In AOM, middle ear effusion (MEE) may be caused by infectious agents, and viral infections may present as thin or serous, while bacterial infections may present as thick and purulent. Therefore, determining the viscosity of the fluid adjacent to the tympanic membrane can provide information that can be used to characterize the membrane.

[0113] Figure 6A The illustration shows a side cross-sectional view of an otoscope 650 disposed within an ear 651 according to some embodiments. Figure 6B The illustration shows a front cross-sectional view of an otoscope 650 of the present disclosure according to some embodiments. Region 150 (in) Figure 6AThe enlarged view shown illustrates a cross-sectional view of the middle ear and tympanic membrane 130 of the subject being examined. The tympanic membrane 130 can be interrogated by an ultrasonic beam 128 from an ultrasonic transducer. The transducer can be mounted on the inner surface of the endoscopic tip 124. The endoscopic tip can be detached from the otoscope 650 via an endoscopic mounting adapter 126. The endoscopic tip may be operatively coupled to or include an excitation generator. In some cases, the excitation generator can generate a pressure excitation. In some cases, the excitation generator can generate a pressure excitation, which is an acoustic excitation, a subacoustic excitation, or an ultrasonic excitation. The pressure excitation generated by the excitation generator can be pulse step or delta (pulse) generation, sinusoidal pressure excitation, square wave excitation, or any combination thereof, and the excitation can be gated burst or continuous. The pressure excitation can be with or without a static positive or negative bias.

[0114] In some examples, the excitation generator produces a pressure excitation, such as blowing air. For example, the spectral mounting adapter 126 and the spectral tip 124 may have a common internal volume. The common internal volume can provide coupling of dynamic pressure from the excitation generator to the ear canal via coupler 122, where air pressure causes displacement of the tympanic membrane 130. The excitation generator can generate pressure changes coupled into the ear canal via the spectral tip 124.

[0115] In some examples, the excitation generator can be an airbag operated by an operator to apply force to a membrane or surface and an air displacement generator that produces alternating pressure, step pressure, or blowing air. The output of the excitation generator can be sealed to the surrounding area of ​​the surface or desealed using a stream of gas, such as the atmosphere or another suitable gas.

[0116] In some examples, the excitation generator can produce acoustic, subsonic, or ultrasonic excitation. For example, the excitation generator can produce sub-audio frequencies below 20 Hz, audio frequencies from 20 Hz to 20 kHz, or ultrasonic frequencies above 20 kHz. In one example, acoustic, subsonic, or ultrasonic excitation can be generated by a piezoelectric transducer. A piezoelectric transducer can convert an electrical signal into a physical displacement, which can then induce a pressure wave. In one example, acoustic, subsonic, or ultrasonic excitation can be generated by a cMUT transducer. In one example, an audio loudspeaker with a voice coil actuator can be used to generate the excitation.

[0117] In addition to and distinct from the excitation generator, an ultrasonic transducer may be provided within the otoscope. The ultrasonic transducer may include any transducer element disclosed herein or variations, examples, or implementations of ultrasonic transducers. In some cases, the ultrasonic transducer and the excitation generator may be the same element.

[0118] like Figure 6BAs shown, the otoscope may include a handle 601 for positioning the endoscope 602. The otoscope may include a video display 603. The display may show the user an optical image of the membrane to be characterized. The display 603 may display ultrasound images. The display 603 may provide a user interface in which various aspects of the otoscope 650 and / or the analysis of ultrasound data are controlled. The otoscope may include on-board digital processing devices, such as within the handle 601 of the device. The otoscope may be connected to a remote device, such as a server, remote storage, remote processing device, etc. The analysis of ultrasound data may be performed on-board or remotely.

[0119] Figure 7A A side cross-sectional view of a viewer 701 according to some embodiments is shown. Figure 7B The illustration shows a front cross-sectional view of a spectral tip 702 according to some embodiments. In some examples, an ultrasonic transducer 703 is disposed within a spectral tip 701. The spectral tip 703 may be disposable. The spectral tip 703 may be disposed near the spectral tip 702 of the spectral tip 701. The spectral tip 703 may include a lens assembly that can help provide an optical image to the user to guide the positioning of the ultrasonic transducer. In some examples, the ultrasonic transducer 703 may be at the center of the spectral tip 703, and optical sensing is therefore performed around the ultrasonic transducer 703. The ultrasonic transducer may be supported by a mesh 705. The mesh 705 may allow electrical signals to be transmitted to a digital processing device.

[0120] The ultrasonic transducer described herein may include a base 706. The base may be mounted within an otoscope via a plate 704. The plate 704 may allow the transducer to be centered or substantially centered within the opening of the otoscope. The plate 704 may be optically transparent. In one example, the plate 704 is glass. The plate 704 may include one or more openings that may allow pressure excitation to be transmitted from the interior of the otoscope tip to the exterior of the otoscope tip. The plate 704 may include one or more conductive portions to allow drive voltage and / or current to be supplied to the transducer. The plate 704 may include one or more insulating layers. The plate 704 itself may include conductive or insulating portions. The plate 704 may be insulated from conductive portions mounted thereon.

[0121] Methods of using the ultrasonic transducer disclosed herein may include providing the ultrasonic transducer; guiding a probe tip within a lumen adjacent to the membrane; directing a disturbance to the surface of the membrane; measuring reflected ultrasonic signals from the membrane surface; and characterizing the viscosity or elasticity of the membrane in response to the disturbance and reflected ultrasound.

[0122] Example

[0123] Example 1 – Otoscopic Test Data

[0124] Figure 8A and Figure 8BExample data traces according to some embodiments are shown, which illustrate false-color contour plots in response to membrane motion in response to disturbances. Figure 8A The relationship between distance from the transducer and time is shown on the axis, and the brightness of the display represents the echo signal intensity. A bright echo is observed at a depth of approximately 13 mm, which corresponds to the tympanic membrane. A bright echo at a depth of 5 mm is part of the external auditory canal. Figure 9A The pressure applied in a time-segmented manner is shown, which corresponds to Figure 8A The ultrasound data observed were detected in the external auditory canal by a pressure sensor (black). The pressure axis is on the left side, and the units are not standardized in this case. Figure 9A It also includes the observed tympanic membrane displacement, since the right-hand axis describes the gray displacement curve, and in this case the unit (micrometer) is not normalized. Figure 9A The position scale in Figure 8A The amplitude was greatly magnified, thus allowing for the observation of 10-micrometer motion based on applied low-frequency square wave pressure stimulation. Similarly, Figure 8B and Figure 9B Similarly, the correlation of tympanic membrane displacement in response to the same square wave pressure disturbance is shown.

[0125] Figure 10A , Figure 10B , Figure 10C and Figure 10D Example viscosity measurements of membranes in the absence of middle ear effusion (MEE) and for effusions of various viscosities are shown according to some embodiments. Figure 10 shows a greatly magnified time axis on a benchtop model of the eardrum. Different oscillatory responses to step changes in pressure were observed in four panels, based on the frequency and duration of the ringing content. The panel process ranges from air to a dilute fluid to a viscous fluid to a “glue” ear. As shown, an increase in the damping term of the ringing is associated with an increase in MEE viscosity. An increase in the ringing frequency is also associated with a decrease in MEE viscosity, as shown. In the case of acute otitis media (AOM), the MEE may be caused by infectious agents. The MEE may be thinned or serous due to viral infection and thickened and purulent due to bacterial infection. The type of effusion can be inferred as serous, mucous, purulent, or a combination thereof based on the measured viscosity.

[0126] Example 2 – cMUT Test Data

[0127] The following comparative examples involve various design elements of ultrasonic transducers and variations of the elements disclosed herein. The following is provided as an example only and is not intended to be limiting. The specifications of the first comparative example group of cMUT elements in Table 1 are shown below. Additionally, the output specifications of the first comparative example in Table 2 are also shown.

[0128]

[0129] Table 1

[0130]

[0131] Table 2

[0132] The following shows a second set of comparison example specifications for cMUT components.

[0133]

[0134] Table 3

[0135] The following shows the third set of comparison example specifications for cMUT components.

[0136]

[0137] Table 4

[0138] Figure 11A and Figure 11B A top view of an example working surface design for a transducer according to some embodiments is shown. For each of Comparative Examples 2 and 3, Figure 11A Each working surface design was implemented and tested on a separate wafer. Comparative Example 2 was implemented and tested on a first wafer and a second wafer to replicate the experiment. No significant changes were found between the first wafer and the second wafer.

[0139] Figure 11A The columns indicate the working surface diameters (50 μm, 60 μm, and 70 μm) of the transducers that were manufactured and tested. The rows indicate the configuration of the release holes manufactured for each working surface diameter. Example release hole arrangements include: 6 holes radially equidistantly distributed on a 42-micron ring centered on the working surface; 6 holes radially equidistantly distributed on a 52-micron ring centered on the working surface; 6 holes radially equidistantly distributed on a 62-micron ring centered on the working surface; 12 holes radially equidistantly distributed on a 42-micron ring centered on the working surface; 12 holes radially equidistantly distributed on a 52-micron ring centered on the working surface; 12 holes radially equidistantly distributed on a 62-micron ring centered on the working surface; 12 holes radially equidistantly distributed on a 16-micron ring centered on the working surface; 12 holes radially equidistantly distributed on a 30-micron ring centered on the working surface; 12 holes radially equidistantly distributed on a 34-micron ring centered on the working surface; 12 holes radially equidistantly distributed on a 52-micron ring centered on the working surface; and 12 holes radially equidistantly distributed on a 62-micron ring centered on the working surface.

[0140] These rows also include release slits. Example release slit arrangements include: slits with a width of 0.8 micrometers and a length of 4 micrometers, and slits with a width of 0.8 micrometers and a length of 8 micrometers. In each illustrated example, the slit may be located radially inwards at a distance of 4 micrometers from the edge of the transducer's working surface.

[0141] Figure 12A and Figure 12B A layout table of test example ultrasonic transducer designs according to some implementations is shown: Design I: 0.9mm x 0.9mm, Design II: 1.2mm x 0.9mm, Design III: 1.4mm x 0.9mm. Figure 12A and Figure 12B This indicates the working surface design for testing each type of ultrasonic transducer. Shading represents the internal characteristics of the cavity. The tested internal characteristics include: A: cavity contains an insulator; B: cavity does not contain an insulator; C: cavity contains a 0.8-micrometer pillar. Figure 12A and Figure 12B Each of the examples illustrates a single layout that is repeated multiple times on a single wafer to address variations on the wafer surface. Up to 26 layouts can be repeated on a single wafer.

[0142] Figure 13A , Figure 13B and Figure 13C A schematic diagram of ultrasonic transducer configurations for each diameter transducer element under test, according to several embodiments, is shown. The ultrasonic transducer designs include Design I: 0.9 mm x 0.9 mm, Design II: 1.2 mm x 0.9 mm, and Design III: 1.4 mm x 0.9 mm. For each Design I, Design II, and Design III, minute variations in the diameter of each transducer's working surface are shown. Electrical contact pads and connections are shown for each design. The electrical connections and pads of the top electrode are shown in dark gray. The electrical connections and pads of the bottom electrode are shown in light gray.

[0143] Figure 13A Three variations of the 0.9 mm x 0.9 mm ultrasonic transducer are shown. In the first variation, 119 transducers with a working surface diameter of 50 micrometers are arranged within a circular region with a hexagonal close-packed structure. In the second variation, 85 transducers with a working surface diameter of 60 micrometers are arranged within the circular region with a hexagonal close-packed structure. In the third variation, 64 transducers with a working surface diameter of 70 micrometers are arranged within the circular region with a hexagonal close-packed structure.

[0144] Figure 13BThree variations of the 1.2 mm x 0.9 mm ultrasonic transducer are shown. In the first variation, 146 transducers with a working surface diameter of 50 μm are arranged within a circular region with a hexagonal close-packed structure. In the second variation, 102 transducers with a working surface diameter of 60 μm are arranged within the circular region with a hexagonal close-packed structure. In the third variation, 79 transducers with a working surface diameter of 70 μm are arranged within the circular region with a hexagonal close-packed structure.

[0145] Figure 13B A variant of the 1.4 mm x 0.9 mm ultrasonic transducer is also shown. In the first variant, 156 transducers with a working surface diameter of 50 micrometers are arranged in a rectangular region with a hexagonal close-packed structure. Figure 13C Two more examples of a 1.4 mm x 0.9 mm ultrasonic transducer are shown. In the second variant, 110 transducers with a working surface diameter of 60 micrometers are arranged within a rectangular region with a hexagonal close-packed structure. In the third variant, 85 transducers with a working surface diameter of 70 micrometers are arranged within a rectangular region with a hexagonal close-packed structure.

[0146] For each transducer in each copy of each layout for each wafer, a "pass" or "fail" assignment is made based on the following parameters measured at the functional bias voltage. For example, a "pass" assignment could be based on the following table of measured frequency, capacitance, and resistance.

[0147]

[0148] Table 5

[0149] Figure 14A , Figure 14B , Figure 14C , Figure 14D , Figure 14E and Figure 14F Frequency sweep measurements of the phase and impedance of an ultrasonic transducer tested according to some embodiments are shown. A portion of the bandwidth of the ultrasonic transducer can be obtained from... Figures 14A to 14F Extracted from measurements. Frequency scan measurements were performed at 80% of the pull-in voltage of the relevant ultrasonic transducer. The pull-in voltage may vary for each type of ultrasonic transducer tested. Figure 14A The frequency scan measurement of the phase of a 50-micron transducer element is shown. Figure 14B The frequency scan measurement of the impedance of a 50-micron transducer element is shown. Figure 14C The frequency scan measurement of the phase of a 60-micron transducer element is shown. Figure 14D The frequency scan measurement of the impedance of a 60-micron transducer element is shown. Figure 14EThe frequency scan measurement of the phase of a 70-micron transducer element is shown. Figure 14F The frequency sweep measurement of the impedance of a 70-micron transducer element is shown. As illustrated, each ultrasonic transducer may have a characteristic resonant frequency. The bandwidth may also differ between each ultrasonic transducer.

[0150] Figure 15A and Figure 15B A graph showing the normalized signal amplitude versus time and ultrasonic transducer size using a laser Doppler vibrometer (LDV) according to some embodiments is shown. Figure 15A As shown, LDV can be used to confirm the function of each element of an ultrasonic transducer. These measurements can indicate that each transducer element is vibrating, represented by the peak value in the signal amplitude. LDV measurements can also be used to determine various operating parameters of the ultrasonic transducer. Additionally, as... Figure 15B As shown, LDV can be used to characterize the frequency and phase of each element in an ultrasonic transducer relative to each other. Figure 15B The normalized signal amplitude versus time for a single transducer element is shown. From these figures, the oscillation frequency of each element at a specific drive voltage can be measured. The phases of the oscillations from each element can be compared to analyze the spatial coherence of the emitted ultrasound.

[0151] Figure 16A and Figure 16B Contour plots of beam spread and ultrasonic loss for a group of operable ultrasonic transducers according to some embodiments are shown. The illustrated devices have angular beam spread between 10 and 20 degrees, bandwidths between 1.2 and 1.8 MHz, and edge lengths between 0.6 and 1.0 mm. Similarly, diffraction losses measured at distances between 12.5 mm and 25 mm perpendicular to the working surface of the transducer element are between 20 and 40 dB.

[0152] Figure 16A The relationship between ultrasonic transducer edge length, center frequency, and beam spread is illustrated. As shown, higher frequencies are associated with lower beam spread, and this is also true for larger ultrasonic transducer sizes. The size of the ear canal may set a functional upper limit for the size of the ultrasonic transducer. Figure 14A , Figure 14B , Figure 14C , Figure 14D , Figure 14E and Figure 14F The phase characteristics shown allow setting a functional upper (and lower) limit for the transducer frequency of a specific transducer configuration. The functional transducer will have ultrasonic beam points on the membrane, generally characterized by the size of the membrane or smaller.

[0153] Figure 16BThe relationship between ultrasonic transducer edge length, center frequency, and beam attenuation / diffraction loss is illustrated. As shown, higher frequencies are associated with lower losses, and this is also true for larger ultrasonic transducer sizes. The size of the ear canal may set a functional upper limit for the size of the ultrasonic transducer. Figure 14A , Figure 14B , Figure 14C , Figure 14D , Figure 14E and Figure 14F The phase characteristics shown allow setting a functional upper (and lower) limit for the transducer frequency of a specific transducer configuration. A functional transducer will have sufficient reflection intensity at the transducer to measure the membrane's vibration, while falling below a threshold to avoid damaging the eardrum.

[0154] Optimal transducers may be subject to several constraints. The beam "spot" size needs to be neither too large (e.g., SNR loss) nor too small (e.g., potentially leading to increased sensitivity to targets and difficulty in aiming). The spot size may be affected by frequency (lower frequencies may produce larger spots, and higher frequencies may produce smaller spots). The spot size may be affected by the transducer edge length (higher indicates a smaller spot, lower indicates a larger spot). These two parameters (frequency and edge length) are combined. The combination of these factors is as follows... Figure 16A As shown.

[0155] These factors, when combined with adjusting the spot size, may be related to the signal-to-noise ratio (SNR). Figure 16B Higher losses in the transducer result in lower SNR. As shown in the figure, the improved transducer can move towards... Figure 16B Running to the upper right, and for example in Figure 16A Near the 15-degree profile in the middle.

[0156] Figure 17 The diagram illustrates the signal-to-noise ratio (SNR) versus distance for a group of operable ultrasonic transducers according to some embodiments. As shown, for all ultrasonic transducer configurations, the SNR decreases with increasing ultrasonic waveform travel distance. As shown, 50- and 60-micron sensors with larger diameter release orifice arrangements exhibit relatively high SNR. As shown, these devices can demonstrate an SNR greater than 15 dB at 80-90% pull-in, measured at distances from 12.5 mm to 25 mm perpendicular to the working surface of the transducer element.

[0157] Digital processing device

[0158] In some embodiments, the imaging components, systems, and methods described herein include digital processing devices or their use. For example, a digital processing device can be used to control various aspects of the transducer elements and ultrasonic transducers described herein. For example, the digital processing device can be used to store transmitted or received ultrasonic waveforms, analyze received data, apply current and / or voltage to the transducer, convert analog signals from the transducer into digital signals, etc. For example, a measuring device such as an otoscope may include a digital processing device on that device. The digital processing device can control various aspects of the otoscope, such as controlling the operation of the ultrasonic transducer, analyzing data, transmitting data to a remote device, etc.

[0159] In other embodiments, the digital processing device includes one or more hardware central processing units (CPUs), general-purpose graphics processing units (GPGPUs), or field-programmable gate arrays (FPGAs) that perform the functions of the device. In other embodiments, the digital processing device also includes an operating system configured to execute executable instructions. In some embodiments, the digital processing device may optionally be connected to a computer network. In other embodiments, the digital processing device may optionally be connected to the Internet, enabling it to access the World Wide Web. In other embodiments, the digital processing device may optionally be connected to a cloud computing infrastructure. In other embodiments, the digital processing device may optionally be connected to an intranet. In other embodiments, the digital processing device may optionally be connected to a data storage device.

[0160] Based on the description herein, suitable digital processing devices include, as non-limiting examples, server computers, desktop computers, laptop computers, notebook computers, subnotebook computers, netbook computers, internet tablet computers, set-top box computers, media streaming devices, handheld computers, internet devices, mobile smartphones, tablet computers, personal digital assistants, video game consoles, and vehicles. Those skilled in the art will recognize that various smartphones are suitable for the systems described herein. Those skilled in the art will also recognize that selected televisions, video players, and digital music players with optional computer network connectivity are suitable for the systems described herein. Suitable tablet computers include those known to those skilled in the art that have a booklet configuration, a panel configuration, or a convertible configuration.

[0161] In some implementations, the digital processing device includes an operating system configured to execute executable instructions. The operating system is, for example, software that includes programs and data, manages the device's hardware, and provides services for executing applications.

[0162] In some embodiments, the device includes a storage and / or memory device. A storage and / or memory device is one or more physical devices used for temporarily or permanently storing data or programs. In some embodiments, the device is volatile memory and requires power to maintain the stored information. In some embodiments, the device is non-volatile memory and retains the stored information when the digital processing device is not powered. In other embodiments, the non-volatile memory includes flash memory. In some embodiments, the non-volatile memory includes dynamic random access memory (DRAM). In some embodiments, the non-volatile memory includes ferroelectric random access memory (FRAM). In some embodiments, the non-volatile memory includes phase-change random access memory (PRAM). In other embodiments, as a non-limiting example, the device is a storage device including CD-ROMs, DVDs, flash memory devices, disk drives, tape drives, optical disc drives, and cloud-based storage. In other embodiments, the storage and / or memory device is a combination of devices such as those disclosed herein.

[0163] In some embodiments, the digital processing device includes a display for transmitting visual information to a user. In some embodiments, the display is a cathode ray tube (CRT). In some embodiments, the display is a liquid crystal display (LCD). In other embodiments, the display is a thin-film transistor liquid crystal display (TFT-LCD). In some embodiments, the display is an organic light-emitting diode (OLED) display. In various other embodiments, the OLED display is a passive-matrix OLED (PMOLED) or an active-matrix OLED (AMOLED) display. In some embodiments, the display is a plasma display. In other embodiments, the display is a video projector. In other embodiments, the display is a combination of devices such as those disclosed herein.

[0164] In some embodiments, the digital processing device includes an input device for receiving information from a user. In some embodiments, the input device is a keyboard. In some embodiments, the input device is a pointing device, which includes, as non-limiting examples, a mouse, trackball, trackpad, joystick, game controller, or stylus. In some embodiments, the input device is a touchscreen or multi-touch screen. In other embodiments, the input device is a microphone to capture voice or other sound input. In other embodiments, the input device is a camera or other sensor to capture motion or visual input. In other embodiments, the input device is Kinect, Leap Motion, etc. In other embodiments, the input device is a combination of devices such as those disclosed herein.

[0165] Reference Figure 18In one specific embodiment, the exemplary digital processing device 1801 is programmed or otherwise configured to control the imaging components and / or instruments described herein. The digital processing device 1801 can regulate the imaging components and / or instruments of various aspects of this disclosure, such as performing processing steps. In this embodiment, the digital processing device 1801 includes a central processing unit (CPU, also referred to herein as a “processor” and “computer processor”) 1805, which may be a single-core or multi-core processor, or multiple processors for parallel processing. The digital processing device 1801 also includes a memory or memory location 1810 (e.g., random access memory, read-only memory, flash memory), an electronic storage unit 1815 (e.g., a hard disk), a communication interface 1820 for communicating with one or more other systems (e.g., a network adapter), and peripheral devices 1825 (e.g., cache, other memory, data storage, and / or electronic display adapters). The memory 1810, electronic storage unit 1815, communication interface 1820, and peripheral devices 1825 communicate with the CPU 1805 via a communication bus (solid line) (e.g., motherboard). Electronic storage unit 1815 may be a data storage unit (or data repository) for storing data. Digital processing device 1801 may be effectively coupled to computer network (“network”) 1830 via communication interface 1820. Network 1830 may be the Internet, the Internet and / or an extranet, or an intranet and / or extranet communicating with the Internet. In some cases, network 1830 is a telecommunications and / or data network. Network 1830 may include one or more computer servers that enable distributed computing, such as cloud computing. In some cases, network 1830 may enable a peer-to-peer network via digital processing device 1801, which allows devices coupled to digital processing device 1801 to act as clients or servers.

[0166] Continue to refer to Figure 18 The CPU 1805 can execute a series of machine-readable instructions that can be embodied in a program or software. The instructions can be stored in a memory location, such as memory 1810. The instructions can point to the CPU 1805, which can then be programmed to perform the methods of this disclosure or otherwise configured to perform the methods of this disclosure. Examples of operations performed by the CPU 1805 may include fetching, decoding, executing, and writing back. The CPU 1805 may be part of a circuit, such as an integrated circuit. One or more other components of the digital processing device 1801 may be included in the circuit. In some cases, the circuit is an application-specific integrated circuit (ASIC) or a field-programmable gate array (FPGA).

[0167] Continue to refer to Figure 18Electronic storage unit 1815 can store files, such as drives, libraries, and saved programs. Electronic storage unit 1815 can store user data, such as user preferences and user programs. In some cases, digital processing device 1801 may include one or more additional external data storage units, such as those located on a remote server communicating via an intranet or the Internet. Digital processing device 1801 can communicate with one or more remote computer systems via network 1830. For example, digital processing device 1801 can communicate with a user's remote computer system.

[0168] Examples of remote computer systems include personal computers (e.g., portable PCs), tablet computers (e.g., Apple...). ® iPad, Samsung ® Galaxy Tab, etc.), telephones, smartphones (e.g., Apple). ® iPhone, Android-enabled devices, Blackberry ® (e.g., personal digital assistants).

[0169] The methods described herein can be executed by machine-executable code (e.g., a computer processor) stored at an electronic storage location (e.g., memory 1810 or electronic storage unit 1815) of digital processing device 1801. The machine-executable code, or machine-readable code, may be provided in software form. During use, the code may be executed by processor 1805. In some cases, the code may be retrieved from electronic storage unit 1815 and stored in memory 1810 for easy access by processor 1805. In some cases, electronic storage unit 1815 may be excluded, and machine-executable instructions may be stored in memory 1810.

[0170] Digital processing device 1801 may include or communicate with an electronic display 1835, which includes a user interface (UI) 1840. Examples of UIs include, but are not limited to, graphical user interfaces (GUIs) and web-based user interfaces. In some cases, electronic display 1835 may be connected to digital processing device 1801 via a network (e.g., via network 1830).

[0171] In some embodiments, the platforms, systems, media, and methods disclosed herein include one or more non-transitory computer-readable storage media that use program encoding comprising instructions executable by an operating system of an optionally networked digital processing device. In other embodiments, the computer-readable storage medium is a tangible component of the digital processing device. In other embodiments, the computer-readable storage medium is optionally removable from the digital processing device. In some embodiments, the computer-readable storage medium includes, as non-limiting examples, CD-ROMs, DVDs, flash memory devices, solid-state storage, disk drives, tape drives, optical disc drives, cloud computing systems, and servers. In some cases, programs and instructions are permanently, substantially permanently, semi-permanently, or non-transitory encoded on the medium.

[0172] In some implementations, the platforms, systems, media, and methods disclosed herein include at least one computer program, or its intended use. A computer program includes a sequence of instructions executable in the CPU of a digital processing device, the sequence of instructions being written to perform a specified task. Computer-readable instructions can be implemented as program modules that perform a particular task or implement a particular abstract data type, such as functions, objects, application programming interfaces (APIs), data structures, etc. Based on the disclosure provided herein, those skilled in the art will recognize that computer programs can be written in various versions of various languages.

[0173] The functionality of computer-readable instructions can be combined or assigned as needed in various environments. In some embodiments, the computer program includes a sequence of instructions. In some embodiments, the computer program includes multiple sequences of instructions. In some embodiments, the computer program is provided from one location. In other embodiments, the computer program is provided from multiple locations. In various embodiments, the computer program includes one or more software modules. In various embodiments, the computer program includes, in part or in whole, one or more web applications, one or more mobile applications, one or more standalone applications, one or more web browser plugins, extensions, add-ons or accessories, or combinations thereof.

[0174] In some implementations, the computer program includes a web application. Based on the disclosure provided herein, those skilled in the art will recognize that, in various implementations, the web application utilizes one or more software frameworks and one or more database systems. In some implementations, the web application is based on a system such as Microsoft... ®The application is built on a .NET or Ruby on Rails (RoR) software framework. In some implementations, the web application uses one or more database systems, which, by way of non-limiting example, include relational, non-relational, object-oriented, associational, and XML database systems. In further implementations, by way of non-limiting example, suitable relational database systems include Microsoft... ® SQL Server, MySQL™ and Oracle ® Those skilled in the art will also recognize that, in various embodiments, the web application is written in one or more versions of one or more languages. The web application can be written in one or more markup languages, presentation definition languages, client-side scripting languages, server-side coding languages, database query languages, or combinations thereof. In some embodiments, the web application is written to some extent in a markup language such as Hypertext Markup Language (HTML), Extensible Hypertext Markup Language (XHTML), or Extensible Markup Language (XML). In some embodiments, the web application is written to some extent in a presentation definition language such as Cascading Style Sheets (CSS). In some embodiments, the web application is written to some extent in a language such as Asynchronous JavaScript and XML (AJAX), Flash... ® Actionscript, Javascript or Silverlight ® It is written in a client-side scripting language. In some implementations, the web application is, to some extent, based on languages ​​such as Active Server Pages (ASP) and ColdFusion. ® Perl, Java™, Java Server Pages (JSP), Hypertext Preprocessor (PHP), Python™, Ruby, Tcl, Smalltalk, Web DNA ® Alternatively, it can be written in a server-side coding language such as Groovy. In some implementations, the web application is written to some extent in a database query language such as Structured Query Language (SQL). In some implementations, the web application integrates with technologies such as IBM... ® Lotus Domino ® The enterprise server product. In some implementations, the network application includes a media player element. In various further implementations, the media player element utilizes one or more of a variety of suitable multimedia technologies, including, by way of non-limiting example, Adobe... ® Flash ® HTML5, Apple ® quick time ® Microsoft® Silverlight ® Java™ and Unity ® .

[0175] In some embodiments, the computer program includes a mobile application provided to a mobile digital processing device. In some embodiments, the mobile application is provided to the mobile digital processing device during manufacturing. In other embodiments, the mobile application is provided to the mobile digital processing device via the computer network described herein.

[0176] Given the disclosure provided herein, mobile applications are created using techniques known to those skilled in the art, including hardware, languages, and development environments. Those skilled in the art will recognize that mobile applications are written in a variety of languages. By way of non-limiting examples, suitable programming languages ​​include C, C++, C#, Objective-C, Java™, Javascript, Pascal, Object Pascal, Python™, Ruby, VB.NET, WML, and XHTML / HTML, or combinations thereof, with or without CSS.

[0177] Suitable mobile application development environments are available from multiple sources. Commercial development environments, through non-restricted examples, include Airplay SDK, alcheMo, and Appcelerator. ® The software includes Celsius, Bedrock, Flash Lite, the .NET Compact framework, Rhomobile, and Work Light mobile platforms. Other development environments, including Lazarus, MobiFlex, MoSync, and Phonegap, are available free of charge through non-restricted examples. Additionally, mobile device manufacturers distribute software development kits, including the iPhone and iPad (iOS) SDK, Android™ SDK, and BlackBerry SDK, through non-restricted examples. ® SDK, BREW SDK, Palm ® OS SDK, Symbian SDK, webOS SDK and Windows ® Mobile SDK.

[0178] Those skilled in the art will recognize that several business forums can be used to distribute mobile applications, by way of non-limiting examples including Apple. ® App Store, Google ® Play, Chrome Web Store, Black Berry ®App World, App Store for Palm devices, App Catalog for webOS, Windows for mobile devices ® Marketplace, for Nokia ® Ovi Store, Samsung devices ® Apps and Nintendo ® DSi Shop.

[0179] In some implementations, a computer program includes a standalone application, which is a program that runs as an independent computer process, rather than an add-on to an existing process, for example, not a plugin. Those skilled in the art will recognize that standalone applications are often compiled. A compiler is a computer program that translates source code written in a programming language into binary object code, such as assembly language or machine code. By way of non-limiting examples, suitable compilation programming languages ​​include C, C++, Objective-C, COBOL, Delphi, Eiffel, Java™, Lisp, Python™, Visual Basic, and VB.NET, or combinations thereof. Compilation is typically performed at least partially to create an executable program. In some implementations, a computer program includes one or more executable compiled applications.

[0180] In some embodiments, the platforms, systems, media, and methods disclosed herein include software modules, server modules, and / or database modules, or the use thereof. Given the disclosure provided herein, software modules are created using machines, software, and languages ​​known in the art, employing techniques known to those skilled in the art. The software modules disclosed herein are implemented in various ways. In various embodiments, a software module includes a file, a piece of code, a programming object, a programming construct, or a combination thereof. In further embodiments, a software module includes multiple files, multiple pieces of code, multiple programming objects, multiple programming constructs, or a combination thereof. In various embodiments, the one or more software modules, by way of non-limiting examples, include web applications, mobile applications, and standalone applications. In some embodiments, the software module is within a computer program or application. In other embodiments, the software module is within more than one computer program or application. In some embodiments, the software module is hosted on a single machine. In other embodiments, the software module is hosted on more than one machine. In a further embodiment, the software module is hosted on a cloud computing platform. In some embodiments, the software module is hosted on one or more machines located in one location. In other embodiments, the software module is hosted on one or more machines located in more than one location.

[0181] In some embodiments, the platforms, systems, media, and methods disclosed herein include one or more databases, or the use of them. Given the disclosure provided herein, those skilled in the art will recognize that many databases are suitable for storing and retrieving information. In various embodiments, by way of non-limiting example, suitable databases include relational databases, non-relational databases, object-oriented databases, object databases, entity-relational model databases, association databases, and XML databases. Other non-limiting examples include SQL, PostgreSQL, MySQL, Oracle, DB2, and Sybase. In some embodiments, the database is Internet-based. In further embodiments, the database is network-based. In still further embodiments, the database is cloud-based. In other embodiments, the database is based on one or more local computer storage devices.

[0182] Although preferred embodiments of the invention have been shown and described herein, it will be apparent to those skilled in the art that these embodiments are provided by way of example only. Many variations, modifications, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein can be used to practice the invention. The scope of the invention is intended to be defined by the following claims, and thereby covers the methods and structures within the scope of these claims and their equivalents.

Claims

1. An ultrasonic transducer, comprising: Multiple capacitive ultrasonic transducer elements; as well as A base having a maximum size and shape adjusted to be disposed within the external auditory canal, wherein the plurality of capacitive ultrasonic transducer elements are mounted on the base; The plurality of capacitive ultrasonic transducer elements form an ultrasonic waveform having an angular beam of greater than 15 degrees propagating through the gas medium and an attenuation loss of greater than 10 dB through the gas medium measured along the main transmission axis at a distance of 12.5 mm to 25 mm.

2. The ultrasonic transducer according to claim 1, wherein the maximum dimension of the base is less than 3 mm.

3. The ultrasonic transducer according to claim 1, wherein the plurality of capacitive ultrasonic transducer elements have a resonant frequency between 1.0 MHz and 3.0 MHz.

4. The ultrasonic transducer of claim 1, wherein each capacitive ultrasonic transducer element has a working surface with a diameter between 10 and 100 micrometers.

5. The ultrasonic transducer according to claim 1, wherein the ultrasonic transducer has an edge length of less than 1.5 mm.

6. The ultrasonic transducer according to claim 1, wherein the plurality of capacitive ultrasonic transducer elements comprises at least 20 capacitive ultrasonic transducer elements.

7. The ultrasonic transducer of claim 1, wherein the plurality of capacitive ultrasonic transducer elements have an average capacitance between 2.5 pF and 10.0 pF.

8. The ultrasonic transducer of claim 1, wherein the ultrasonic transducer is configured to be disposed within the endoscope of an otoscope.

9. The ultrasonic transducer of claim 1, wherein one or more of the plurality of capacitive ultrasonic transducer elements have a plurality of openings in their working surface.

10. The ultrasonic transducer of claim 9, wherein the plurality of openings are arranged in a circle with a diameter of at least 10 micrometers.

11. The ultrasonic transducer of claim 9, wherein the plurality of openings comprises at least three release holes for each capacitive ultrasonic transducer element.

12. The ultrasonic transducer according to claim 9, wherein the plurality of openings are circular in shape.

13. The ultrasonic transducer of claim 9, wherein the plurality of openings are curved in shape.

14. The ultrasonic transducer of claim 9, wherein the plurality of openings comprises a release slit having a slit width of at least 0.4 micrometers and a spring length of at least 2 micrometers.

15. The ultrasonic transducer according to claim 1, wherein the plurality of capacitive ultrasonic transducer elements are arranged on the base in a hexagonal close-packed structure.

16. The ultrasonic transducer of claim 1, wherein the plurality of capacitive ultrasonic transducer elements are arranged in a circular region on the base, the diameter of the circular region being equal to the edge length of the ultrasonic transducer.

17. The ultrasonic transducer of claim 1, wherein the plurality of capacitive ultrasonic transducer elements are arranged in a rectangular region on the base, the longest side of the rectangular region being equal to the edge length of the ultrasonic transducer.

18. The ultrasonic transducer according to claim 1 further includes a plurality of pads, the pads forming a plurality of electrical contacts.

19. The ultrasonic transducer of claim 1, wherein the plurality of capacitive ultrasonic transducer elements have an average cavity height of less than 1500 nm.

20. The ultrasonic transducer of claim 1, wherein the ultrasonic transducer has a pull-in voltage of less than 80% of 85V.

21. The ultrasonic transducer of claim 1, wherein the ultrasonic transducer has a signal-to-noise ratio greater than 15 dB measured along the main transmission axis of the transducer at a distance of 12.5 mm to 25 mm.

22. The ultrasonic transducer of claim 1, wherein the ultrasonic transducer has a partial bandwidth of more than 10%.

23. The ultrasonic transducer of claim 1, wherein the ultrasonic transducer has a projected intensity of 10 Pa or greater measured at a distance of 12.5 mm to 25 mm along the main transmission axis of the transducer.

24. The ultrasonic transducer of claim 1, wherein the ultrasonic transducer has a frequency bandwidth of ±25% of the center frequency at half maximum width at half maximum (FWHM).

25. An otoscope system, comprising: The ultrasonic transducer and endoscopic device according to any one of claims 1 to 24, wherein the ultrasonic transducer is disposed within the endoscopic device and wherein the endoscopic device is configured to be removably coupled to an otoscope.

26. A method for measuring a fluid, the method comprising: Provide an ultrasonic transducer according to any one of claims 1 to 24; Apply aerodynamic challenges to the surface of the fluid; as well as The ultrasonic transducer was used to observe the disturbance in the waveform reflected from the surface in response to the aerodynamic challenge.

27. A method for characterizing a fluid, the method comprising: Provide an ultrasonic transducer according to any one of claims 1 to 24; as well as An ultrasonic beam generated by the ultrasonic transducer is directed through a gaseous medium to the surface of the fluid, wherein the distance between the fluid and the working surface of the ultrasonic transducer is 12.5 mm to 25 mm, wherein the ultrasonic beam has an angular beam with a propagation angle greater than 15 degrees through the gaseous medium, and wherein the ultrasonic beam has an attenuation loss greater than 10 dB through the gaseous medium.

28. A method for characterizing fluid behind the eardrum in the ear canal, the method comprising: Receives a set of data from the ultrasonic transducer of any one of claims 1 to 24, wherein the ultrasonic transducer is disposed within the ear canal of the object, wherein the ultrasonic transducer has an edge length of less than 1.5 mm. From the set of data, determine a first subset of data corresponding to the response to the aerodynamic challenge and a second subset of data corresponding to the dataset that was not challenged; Determine the viscosity of the fluid; as well as The fluids are classified.

29. An otoscope, comprising: Disposable speculum; Multiple capacitive ultrasonic transducers are disposed within the endoscopic eyepiece, wherein the multiple ultrasonic transducer elements form an ultrasonic transducer, wherein the ultrasonic transducer is disposed within the tip of the endoscopic eyepiece, and wherein the ultrasonic transducer has an angular beam propagating through a gas medium of greater than 15 degrees and an attenuation loss through the gas medium of greater than 10 dB measured along the main transmission axis of the transducer at a distance of 12.5 mm to 25 mm. as well as A base, wherein the base has a maximum dimension of less than 2.5 mm, and wherein the plurality of ultrasonic transducers are disposed on the base.

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