943 results about "Acoustic impedance" patented technology

An apparatus and method using a backing block having a variable acoustic impedance as a function of elevation or azimuth, to achieve a desirable apodization of the aperture of an ultrasound transducer stacked with the backing block. The backing block has a gradient profile in acoustic impedance that changes from a minimum value to a maximum value along the elevation direction and/or azimuthal direction of the stacked ultrasound transducer. Typically, the backing block has an elevation gradient profile in acoustic impedance that increases from a minimum value of acoustic impedance near the center of the backing block to a maximum value of acoustic impedance at opposing lateral faces of the backing block. The backing block can be discretely segmented in acoustic impedance, with as many segments as are practically manufacturable. An individual segment can have a uniform or variable acoustic impedance. The backing block can be continuous in acoustic impedance, with a minimum acoustic impedance in the center and a maximum acoustic impedance at two or more planar lateral faces.

Methods for manufacturing ultrasonic waveguides having improved velocity gain are disclosed. Additionally, methods for manufacturing ultrasonic medical devices including the ultrasonic waveguides are disclosed. Specifically, the ultrasonic waveguides comprises a first material having a higher acoustic impedance and a second material having a lower acoustic impedance.

Ultrasonic waveguides having improved velocity gain are disclosed for use in ultrasonic medical devices. Specifically, the ultrasonic waveguides comprises a first material having a higher acoustic impedance and a second material having a lower acoustic impedance.

The film bulk acoustic resonator (FBAR) device comprises a substrate, an acoustic Bragg reflector over the substrate, a piezoelectric element over the acoustic Bragg reflector, and a remote-side electrode over the piezoelectric element. The acoustic Bragg reflector comprises a metal Bragg layer juxtaposed with a plastic Bragg layer. The large ratio between the acoustic impedances of the plastic material of the plastic Bragg layer and the metal of the metal Bragg layer provides sufficient acoustic isolation between the FBAR and the substrate for the frequency response of the FBAR device to exhibit minor, if any, spurious artifacts arising from undesirable acoustic coupling between the FBAR and the substrate.

A microphone has a substrate including an acoustically transparent substrate region, a lid with an acoustically transparent lid region, and a membrane which is held by a membrane carrier between the lid and the substrate. The acoustically transparent substrate region or the acoustically transparent lid region is provided with at least one impedance hole sized so that an acoustic impedance of the impedance hole is larger than an acoustic impedance of the acoustically transparent region of the respective other region of substrate region and lid region.

In one embodiment the invention comprises a particle velocity sensor that includes a housing with a geophone mounted in the housing. A fluid that substantially surrounds the geophone is included within the housing. The particle velocity sensor has an acoustic impedance within the range of about 750,000 Newton seconds per cubic meter (Ns/m<3>) to about 3,000,000 Newton seconds per cubic meter (Ns/m<3>). In another embodiment the invention comprises method of geophysical exploration in which a seismic signal is generated in a body of water and detected with a plurality of co-located particle velocity sensors and pressure gradient sensors positioned within a seismic cable. The output signal of either or both of the particle velocity sensors or the pressure gradient sensors is modified to substantially equalize the output signals from the particle velocity sensors and the pressure gradient sensors. The output signals from particle velocity sensors and pressure gradient sensors are then combined.

A vehicle tire communication and information system for viewing air psi and other characteristics that affects psi in a tire includes un-obstructive sensors embedded in a silicon substrate and etched in a re-enforced micro-fibered material to enable excellent detection platform, sensitivity, and selectivity within the detection environment. The embedded sensors facilitate detection and communication efficiency and transforms electrical energy into acoustic energy indicative of data transmission to a wireless electronic control module, allowing a nitride membrane to march the acoustic impedance of the air inside the tire to enable pressure waves indicative of the tire pressure.

A component operating with bulk acoustic waves has a carrier substrate, a thin-film resonator and an acoustic mirror arranged between the resonator and carrier substrate. The acoustic mirror is formed by at least one high acoustic impedance layer, which is covered by a low acoustic impedance layer and the uppermost low impedance acoustic layer is planarized to form a flat planar surface on which the thin-film resonator is formed.

Acoustic shielding system and method for protecting and shielding non-targeted regions or tissues that are not intended to be treated by ultrasonic procedures from acoustic energy using a shield. In some embodiments, the shield comprises multiple layers made of one or more materials with one or more acoustic impedances. In some embodiments a multilayered shield includes materials with relatively different acoustic impedance levels. In some embodiments, the shield includes active components such as energy diversion devices, heating, cooling, monitoring, and/or sensing. In some embodiments, the shield is configured to protect an eye, mouth, nose or ear while allowing the ultrasound to treat the surrounding tissue. One embodiment of an eye shield is configured to fit under at least one eyelid and over a portion of the eye.

A resonator device includes a piezoelectric resonator having a detuning layer sequence arranged on the piezoelectric resonator. The detuning layer sequence includes at least a first layer having a high acoustic impedance and a second layer having a low acoustic impedance.

The decoupled stacked bulk acoustic resonator (DSBAR) device has a lower film bulk acoustic resonator (FBAR), an upper FBAR stacked on the lower FBAR, and an acoustic decoupler between the FBARs. Each of the FBARs has opposed planar electrodes and a layer of piezoelectric material between the electrodes. The acoustic decoupler has acoustic decoupling layers of acoustic decoupling materials having different acoustic impedances. The acoustic impedances and thicknesses of the acoustic decoupling layers determine the acoustic impedance of the acoustic decoupler, and, hence, the pass bandwidth of the DSBAR device. Process-compatible acoustic decoupling materials can then be used to make acoustic decouplers with acoustic impedances (and pass bandwidths) that are not otherwise obtainable due to the lack of process-compatible acoustic decoupling materials with such acoustic impedances.

A resonator apparatus has a piezoelectric resonator as well as an acoustic reflector which has a layer having a high acoustic impedance and a layer having a low acoustic impedance. The thickness of one layer is set different from a quarter of the wavelength in this layer at the operating frequency due to technological limitations in the manufacturing of this layer, and the thickness of the other layer is set dependent from the one layer, such that a predetermined minimum quality of the acoustic reflector is attained.

An ultrasonic transducer according to the present invention includes: a piezoelectric body 4 to set up ultrasonic vibrations; an acoustic matching layer 3 made of a material with a density of 50 kg/m³ to 1,000 kg/m³ and an acoustic impedance of 2.5×10³ kg/m²/s to 1.0×10⁶ kg/m²/s; a lower acoustic matching layer 9 provided between the piezoelectric body 4 and the acoustic matching layer 3; and a structure supporting member 6 that supports the lower acoustic matching layer 9 and the piezoelectric body 4 thereon and shields the piezoelectric body 4 from a fluid that propagates the ultrasonic vibrations. The ultrasonic transducer includes a protective portion, which contacts with at least a portion of a side surface of the acoustic matching layer 4. This protective portion is defined by a portion of the lower acoustic matching layer 9 and forms an integral part of the lower acoustic matching layer 9.

The invention is directed biopsy site markers and methods of marking a biopsy site, so that the location of the biopsy cavity is readily visible by conventional imaging methods, particularly by ultrasonic imaging. The biopsy site markers of the invention have high ultrasound reflectivity, presenting a substantial acoustic signature from a small marker, so as to avoid obscuring diagnostic tissue features in subsequent imaging studies, and can be readily distinguished from biological features. The several disclosed embodiments of the biopsy site marker of the invention have a high contrast of acoustic impedance as placed in a tissue site, so as to efficiently reflect and scatter ultrasonic energy, and preferably include gas-filled internal pores. The markers may have a non-uniform surface contour to enhance the acoustic signature. The markers have a characteristic form which is recognizably artificial during medical imaging. The biopsy site marker may be accurately fixed to the biopsy site so as to resist migration from the biopsy cavity when a placement instrument is withdrawn, and when the marked tissue is subsequently moved or manipulated.

The present invention relates to a probe, which is adapted to match acoustic impedances and shield undesired signals, and an ultrasound diagnostic system configured to use such a probe. The probe for conducting ultrasound diagnosis includes a transducer array for transmitting ultrasound signals to a target object and receiving the ultrasound signals reflected from the target object. The probe of the present invention also includes multiple membranes for covering the transducer array, wherein the multiple membranes include at least two membranes formed from different materials and having different thicknesses.