Hewlett-packard Company

Agilent Technologies, Inc.

Hewlett-packard Corporation

Agielnt Technologies

J Fleming Dias

Henry E Karrer

Ganapati R Mauze

Hewlett E Melton, Jr

Richard J Pittaro

Richard D Pering

Alexander Tykulsky

King-Wah W Yeung

John D Larson

Mir S Seyed-Bolorforosh

David A Wilson

Amin M Hanafy

H Edward Karrer

A method is provided for fabricating an annular ring transducers for determining the velocity of a fluid flow. A novel and accurate flow measurement system is fabricated for measuring transit time of a fluid flow using chirp signals, and a pneumotachometer with annular ring transducers is also disclosed.

Method for fabricating an annular ring transducer

An accurate and reliable pneumotachometer with annular ring transducers for determining the velocity of a fluid flow is provided. A novel and accurate flow measurement system for measuring transit time of a fluid flow using chirp signals and a pneumotachometer with annular ring transducers is also disclosed.

Pneumotachometer having annular ring transducers

A technique for efficiently sampling blood from body tissue by reducing pressure on the body tissue. In the present technique a body tissue is placed under reduced pressure to improve perfusion of blood in the body tissue before lancing. An embodiment of this apparatus includes a lancet carried by a piston slidable in a housing, a mechanism for transmitting mechanical energy internally in the apparatus for creating the reduced pressure on the body tissue. The apparatus also includes a driver that drives the lancet for lancing. The apparatus has a head in the housing for contacting the body tissue in an air-tight manner against suction forces. In the head facing the body tissue is a channel in which the air pressure can be reduced.

Apparatus and method for efficient blood sampling with lancet

A direct contact scanner uses a fiber acoustic waveguide to convey ultrasound from an ultrasound transducer to a direct contact area. The waveguide extends from a main body of the scanner into an oblong nose, and terminates in a deflector. To minimize thickness of the nose, the waveguide and deflector are rotated about an ultrasound transmission axis of the waveguide, enabling the scanner to be used in a variety of situations where quarters are cramped. A coupling fluid conveys ultrasound between the deflector and a radome, which directly contacts the object to be scanned. Using the waveguide, an ultrasound transducer and supporting electronics may be distanced from the direct contact area and separated from the fluid, thereby insulating the fluid from possible electronic leakage currents and heat.

Direct contact scanner and related method

A noninvasive blood chemistry measurement method and system isolate measurement contributions due to a patient's blood to accurately measure blood chemistry. In accordance with a first preferred embodiment of the present invention a noninvasive blood chemistry measurement method decreases the blood volume within a patient's body part relative to the normal blood volume in the body part and performs a baseline measurement. Blood volume is then increased and a second measurement is performed. Comparison of the second measurement to the baseline measurement isolates the measurement attributes of the patient's blood. In accordance with a second preferred embodiment of the present invention a noninvasive blood chemistry measurement system decreases blood volume by applying mechanical pressure to a body part. In accordance with a third preferred embodiment of the present invention, blood volume in the body part is decreased using a pressure cuff. In a fourth embodiment, a noninvasive probe accurately measures blood chemistry and uses a suction cup to increase blood volume at the blood chemistry measurement site.

Noninvasive blood chemistry measurement method and system

A system and method for coupling acoustic energy within a waveguide provides highly efficient and sensitive acoustic energy generation and detection. In particular, an ultrasound angioplasty system is described which makes use of an end-fire array of ring transducers to produce highly directionalized sound within an acoustic waveguide. The transducers can be made circularly symmetric, and may be composed of multiple segments for generating sound waves in independent x and y spatial modes within the acoustic waveguide. Each ring transducer is optimally spaced 1/2.lambda..sub.L from its neighbor transducers, such that alternate transducers transduce 180-degrees out of phase, and may have their electrical end inverted for common drive, or for summing of transducer electrical outputs when the array is used as a detector. The phased array may also be used in a resonant acoustic energy system used to detect pressure variations or reflections from a substance, for example, for detecting the progress of chemical reactions, liquid level sensing, etc., imaging, or in various other ultrasound applications.

Method and system for coupling acoustic energy using an end-fire array

Method and system for coupling acoustic energy using shear waves

An ultrasonic probe, such as a catheter, includes an array of electroacoustic transducer elements arranged about a central region, with each element having a radiating surface directed to define a first acoustic energy path having a component of direction that is toward the central region. That is, the elements are inwardly directed. Within the central region is an acoustic reflector that reflects the acoustic energy along a second path to an object to be imaged. In another embodiment, the transducer elements are directed to project acoustic energy generally parallel to the axis of the ultrasonic probe, with the acoustic reflector providing reflection for defining an interrogation beam.

Catheter probe having a fixed acoustic reflector for full-circle imaging

An apparatus for providing efficient transmission of a beam of acoustic wave between an ultrasonic transducer and a remotely located body under examination by the beam. The apparatus includes a housing having an interior arranged so that the ultrasonic transducer is disposed therein. A prism is acoustically coupled with the transducer and with an acoustic waveguide having a longitudinal dimension extending outwardly from the interior of the housing. The acoustic prism is fixedly coupled with a proximate portion of the waveguide so as to provide efficient transmission of the beam of acoustic waves between the prism and the waveguide. Accordingly, The beam of acoustic waves is transmitted from the transducer, through the prism, and along the longitudinal dimension of the waveguide, to a distal portion of the waveguide. The distal portion of the waveguide is inserted into a remotely located patient's body under examination. The distal portion of the waveguide emits the ultrasonic beam, scanning the tissue of interest.

Apparatus for coupling acoustic waves with an acoustic waveguide

A method of forming an impedance matching layer of an acoustic transducer includes geometrically patterning impedance matching material directly onto a radiating surface of piezoelectric substrate. In one embodiment, the matching layer is deposited onto the piezoelectric substrate and photolithographic techniques are utilized to pattern the matching layer to provide posts tailored to better match the piezoelectric substrate to a medium into which acoustic waves are to be transmitted. A nominal layer of metal between the posts and the piezoelectric substrate improves the attachment of the matching material to the substrate. The nominal layer may be chrome-gold and the matching material may be copper. Typically, the radiating surface is the substrate front surface from which acoustic waves are directed into a medium of interest, e.g., water or human tissue. However, the radiating surface may be the substitute rear surface, with the patterned matching layer providing acoustic matching to a backing layer for absorbing acoustic energy. In another embodiment, matching layers of different acoustic impedances are deposited and patterned on both the front and rear surfaces to provide matching for effective transmission into the medium of interest and into an acoustic absorptive backing medium.

Method for making integrated matching layer for ultrasonic transducers

This invention is a magnetostriction transducer and an intraoperative probe for acoustic imaging. The magnetostriction transducer has a coil and a magnetostriction element deposited on a portion of the acoustic waveguide that is inserted inside the coil. The magnetic field of the coil threads into the magnetostriction element and, due to the alternating magnetic field, the magnetostriction element changes its length at a rate equal to the frequency of the magnetic field. These length changes excite, among others, longitudinal waves in the core of the acoustic waveguide. The intraoperative probe has an array of acoustic waveguides bonded together. Each acoustic waveguide in the intraoperative probe has a transducer, such as a magnetostriction transducer of a piezoelectric transducer, that couples acoustic signals into the acoustic waveguides. The intraoperative probe can image the body without the extra hardware needed to rotate an acoustic waveguide by stepping an acoustic beam across the aperture of the intraoperative probe. This invention has the advantage of imaging internal organs without exposing them to danger of leakage currents.

Magnetostriction transducer and an intraoperative probe for acoustic

A catheter tip imaging probe varies the effective radius of resolution of an acoustic beam by translating the focal length. Varying the effective radius improves the resolution at any point of interest along the arterial walls. The focal length can be dynamically translated by deflecting either the transducer or the mirror in a conventional imaging probe.

Intravascular imaging catheter tip having a dynamic radius

Spherical annulus piezoelectric transducers 62, 64 and spherical disc piezoelectric transducer 66 form a spherical shell having a radius of curvature R with a focal point 70 near the end of cladded-core acoustic waveguide 72. Each transducer 62, 64, 66 generates a bulk acoustic wave of a unique frequency and transmits it to focal point 70 where it enters core 74 of cladded-core acoustic waveguide 72. Alternatively, a conical annulus piezoelectric transducers 92, 116 on a prism 90 generate bulk acoustic waves of multiple discrete frequencies and focus them through cladding 75 and into core 74 of cladded-core acoustic waveguide 72. Surface acoustic waves of multiple discrete frequencies can be generated by multiple sets of curvilinear interdigital conductors 132, 134 on a piezoelectric substrate 122. The shape of curvilinear interdigital conductors 132, 134 focuses the surface acoustic waves at focal point 70 located near the end of acoustic waveguide 72. The surface acoustic waves are converted into bulk/longitudinal waves by either curvilinear corrugations 142, 146 or by a coupling medium that causes the surface acoustic waves to become leaky longitudinal waves. Alternatively, the surface acoustic waves can be coupled to the core of the acoustic waveguide by converting them into either bulk/longitudinal waves or leaky longitudinal waves and guiding them through the cladding to the core. When the acoustic signals travel through the cladding to couple to the core, the acoustic waveguide can transmit optical signals.

Apparatus that generates acoustic signals at discrete multiple

An ultrasound transducer for intravascular examinations comprises an interleaved series of eccentric elliptical electrodes disposed on the back face of a piezoelectric substrate that has been alternately poled in the thickness dimension. The back face of the transducer is coupled to air, while impedance-matching layers are on the front face of the transducer. The front face is concave spherical to provide a geometric focus. The electrodes are driven at an ultrasound frequency. This arrangement results in a longitudinal-mode ultrasound transmission through the front face of the transducer. The eccentricity of the electrodes precompensates for distortion imposed by a cylindrical window. The pitch (spacing) of the electrodes increases radially, reducing speckling in the ultrasound image. This transducer provides for high-frequency intravascular examinations, and thus correspondingly high-resolution images, without using impractically thin piezoelectric substrates. In addition, the geometric focus, the predistortion, and the speckle-reduction all reduce the artifacts in the resulting high-resolution ultrasound image.

Growing community of inventors

Palo Alto, CA, United States of America

J Fleming Dias