Siemens Aktiengesellschaft

Sri International

Adept Technology, Inc.

Picker Corporation

Stanford Research Institute

Sanford Research Institute

Jon C Taenzer

Philip S Green

S David Ramsey, Jr

Louis F Schaefer

Donald J Burch

Joe R Suarez

John F Holzemer

Steven H Johnson

The invention is a variable reluctance motor using a stator comprised of a plurality of single tooth poles, wound so that every other pole of the same phase is of oppposite polarity. A movable member is also provided with a plurality of single tooth pole members. The spacing of rotor and stator poles is equal.

Variable reluctance stepper motor

A control system for a brushless DC torque motor is disclosed. The motor comprises three coils, the wires at the end of each coil being brought out and connected to an amplifier that provides the current control signals to the coils. These control signals are generated based on a combination of commutation input command bits which are effectively multiplied by a pulse-width modulation control input word to form a pseudo-sine wave current signal at the input to each coil. By combining the pulse width modulated (pwm) current command word with an input command which defines a square wave, a pseudo-sine wave signal is provided for each coil which effectively controls the current to the motor coil in accordance with the value of the pwm commands. In each amplifier, the current control signal is compared with a servo feedback signal from the coil to define an error signal which, when amplified, becomes the actual input current signal to the coil. In order to allow for the fact that this is a bipolar system, a dead zone is defined between positive and negative drive signals so that no overlap occurs in the signals which could cause undue stress to the output transistors. Appropriate protection is also provided against numerous fault conditions, for example, any open circuit or short circuit condition.

Motor control circuit and drive amplifier for a permanent magnet DC

An amplifier circuit for controlling a direct drive motor has an input circuit for converting the digital control word to a pulse width modulated signal which is coupled to a control input of the amplifier through an isolation device. This isolation device and the other gain devices as well as many of the test circuitry devices and the feedback circuitry are referenced to a common, internally generated, stable reference level voltage. An input position control signal is coupled to an operational amplifier whose other inputs is a signal representing the current through the coil at any time. The output of the operational amplifier is a signals which will seek to equalize the two inputs signals. The output of the operational amplifier is coupled to the two controlling transistors which provide the drive current to the motor coil. Diodes are appropriately coupled to the switching transistor to incorporate regeneration effects for the minimization of power consumption. A monitor is also provided to track current flow out of the high voltage source to detect any shorts in the output system or load. Two transistor switches are provided between the initial high-voltage source and the coils. A simplified logic circuitry is provided which responds to the detection of failure mode operating conditions and terminates the operation of these switches to cut off high voltage to the coils.

Motor control circuit for variable reluctance motor

A pair of image fields which are views of an object from two slightly different angles at near enough the same time to constitute a stereo image field pair is produced by providing a pair of similar coaxial counterrotating refracting prisms between the object viewed and the image field and alternately transmitting an image field through the prisms on opposite sides of the plane through or parallel to the central axis of the two prisms.

Real time stereo imaging

Method and apparatus for obtaining quantitative velocity profile measurements and for displaying the same are disclosed. From such velocity measurements, instantaneous volume flow within a vessel across which the measurements are obtained is calculated. In one operating mode, a real-time display of quantitative velocity profiles is provided together with a scrolling display of a plurality of total instantaneous volume flow measurements. In another operating mode, velocity profiles obtained at corresponding points in successive cardiac cycles are averaged to obtain a plurality of average velocity profiles which are selectively displayed under operator control. In this mode of operation, a fixed display of total instantaneous volume flow measurements obtained over a period of time which includes at least one cardiac cycle is provided. A movable pointer adjacent the display of total instantaneous volume flow values and under operator control is provided to identify the point in the cardiac cycle selected for display of an associated velocity profile. Means for calculating volume flow over a cardiac cycle, and for numerically displaying said average also is provided. Depth control means control both depth and gain functions of the pulsed Doppler system.

Ultrasonic imaging with volume flow measuring method and apparatus

The insonification apparatus is designed for the examination of an object, preferably for medical examinations. The apparatus contains an ultrasonic wave-generating transducer for emitting ultrasonic waves toward an examination plane, and an imaging device having principal planes for passing ultrasound waves received from the examination plane toward an imaging plane. The acoustic image formed in the imaging plane is received by a receiving transducer and transferred into electrical signals. The apparatus also contains an ultrasound condensing device such as a lens, a mirror, or a combination of such elements. This condensing device forms an ultrasonic image of the wave-generating transducer in the aperture of the imaging device. Thus, an increased uniformity of the intensity distribution in the image plane and an increased image contrast for high-spatial frequency information are obtained.

Insonification apparatus for an ultrasound transmission system

An ultrasonic transmitting and/or receiving transducer is disclosed which includes a piezoelectric body with electrodes at opposite faces thereof. At least one of the electrodes is in the form of an elongated strip conductor such that the transducer also functions as a lossy delay line. The beam pattern of the transducer is dependent upon the delay of the delay line. A high permeability member such as a ferrite body is located adjacent the elongated strip conductor to increase the distributed inductance of the delay line and, consequently, the delay thereof. The permeability of the ferrite body is controlled by use of a drive coil adjacent thereto. By time varying the drive current to the coil, the acoustic beam pattern is time varied. By using a spiral shaped elongated strip conductor on a cylindrical shaped piezoelectric body, a focusing transducer is provided.

Inherent delay line ultrasonic transducer and systems

The apparatus incorporates an ultrasonic wave-generating transducer for providing ultrasonic waves, a first and a second ultrasound window, a first guiding device for guiding the ultrasonic waves to the first window, an ultrasonic receiving transducer for transforming an acoustic image field received from the second window into electrical signals, and a second guiding device for guiding ultrasound transmitted through the second window to the receiving transducer. The ultrasound windows define an examination gap for insonifying a patient's organ positioned therein. The apparatus further incorporates a curved mirror for focusing the acoustic image field received from the gap onto the receiving transducer. The mirror is attached to a rocking device. Thus, the curved mirror is also used for scanning or sweeping the acoustic image field across the receiving transducer. Thus, an image of the object plane under examination is obtained. Preferably, the curved mirror may be filled with a substance having a low velocity of ultrasound as compared to the adjacent fluid medium contained in the second guiding device. This design eliminates the need for a large number of refractive and reflective surfaces, thereby reducing artifacts in the image.

Ultrasound apparatus for medical examinations

The apparatus incorporates an ultrasonic wave-generating transducer for providing ultrasonic waves, a first and a second ultrasound window, a first guiding device for guiding the ultrasonic waves to the first window, an ultrasonic receiving transducer for transforming an acoustic image field received from the second window into electrical signals, and a second guiding device for guiding ultrasound transmitted through the second window to the receiving transducer. The ultrasound windows define an examination gap for insonifying a patient's organ positioned therein. The apparatus further incorporates a lens for focusing the acoustic image field received from the gap onto the receiving transducer. A mirror device, preferably a plane mirror, is associated with the second guiding device. This mirror deflects ultrasound energy that passes through the gap in a direction which is different from the main insonification direction in the gap. The second guiding device may comprise a compact scanning means for sweeping the acoustic image field across the receiving transducer.

Compact ultrasound apparatus for medical examination

The ultrasonic apparatus contains an imaging lens for focusing ultrasound waves, a diverging device for receiving converging ultrasound waves from the lens and for transmitting ultrasound waves such that beams coming from a single object point are focused along a focal line, and an ultrasound detector positioned at the focal line indicating the ultrasound waves. The detector contains a large number of elongated detector elements. In particular, the diverging device comprises an acoustic mirror containing a reflecting surface which has a diverging effect on impinging beams of ultrasound waves. Preferably, the mirror may have a reflecting surface which is formed by a large number of parallel parabolic lines.

Ultrasound camera

A real time scanned transducer ultrasonic imaging system is disclosed having an improved mechanical scanning system for reciprocating its transducer. The transducer is immersed in a fluid containing chamber. The drive system includes monitoring equipment which produces signals indicating transducer position. Imaging electronics processes (1) electrical signals produced by the transducer in response to ultrasonic echoes, and (2) the transducer position signals from the monitor. Display apparatus produces substantially real time ultrasonically derived images. The drive system includes a transducer carriage which reciprocates on guide rod structure. A drive arm is coupled to the carriage by a compliant coupling element. A drive shaft attached to the drive arm extends through a wall of the chamber, such that the drive shaft oscillates the drive arm.

Transducer drive for ultrasonic imaging

A diagnostic ultrasound real time B-scanner system has an improved probe assembly for fluid coupling a movable axis transducer to a patient's body. Pressure is maintained both low and constant by means of a passive pressure compensation apparatus. The probe includes apparatus containing the transducer and a fluid medium and including a compliant subject contacting bag. Pressure exerted by the bag on a subject is a function of (1) the pressure exerted on the fluid medium and (2) the orientation of the probe, due to the shifting weight of the fluid. The passive pressure compensator apparatus includes a gravity actuated apparatus for varying the pressure on the fluid medium as a function of the spatial orientation of the probe. This pressure variation compensates for the weight of the fluid medium and stabilizes the coupling pressure on the surface of the patient's body.

Low and constant pressure transducer probe for ultrasonic diagnostic

Pulsed real-time B-scan ultrasonic method and apparatus are disclosed together with pulsed Doppler Ulrasonic method and apparatus. The B-scan apparatus includes a pulse operated transmitter and receiver operating at a first frequency, and the Doppler apparatus includes a pulse operated transmitter and receiver operating at a second frequency sufficiently far removed from the B-scan frequency to avoid interference therebetween. A synchronous pulse operation of the B-scan and Doppler systems is provided. The sysem includes a visual display means to which the receiver outputs are connected through a multiplexer operated to pass the B-scan receiver output to the visual display means whenever such B-scan output is present. The Doppler apparatus includes means for temporarily storing the Doppler receiver output, which stored Doppler signals subsequently are read out through the multiplexer to the visual display means between select lines of B-scan display. A simultaneous display of the B-scan image and a Doppler profile is provided when desired. A control stick unit, under one-hand control of the operator, is used to select the position of the line along which the Doppler profile is obtained and displayed. A cursor generator, under control stick control, is used to generate a cursor signal for display of a cursor along which the Doppler profile is displayed. The B-scan apparatus is operable with a normal or magnified display of a section of the object under investigation. Also, a reticle signal generator is included for t

Real-time ultrasonic B-scan imaging and Doppler profile display system

Mechanical scanning apparatus is shown which includes a parallelogram linkage comprising a pair of parallel arms and parallel first and second connecting links adjacent opposite ends of the arms pivotally connected thereto. Transducer means, such as an ultrasonic transducer or transducer array, included in the ultrasonic imaging system, or the like, are attached to said first connecting link for movement therewith. First supporting means, adjacent the arm ends opposite the transducer means, support the parallelogram linkage thereat for movement along an arcuate path which closely approximates a portion of an ellipse adjacent a focus thereof. Constraining means, intermediate the first supporting means and transducer means, limit an intermediate portion of the parallelogram linkage to generally straight line movement along a path which extends substantially along a portion of the major axis of the ellipse. Upon drive operation of the linkage the transducer means, which are located at the minor axis of the ellipse, are moved with a linear translational motion along said minor axis. The constraining means may include a third connecting link extending between the arms which link is connected to a shaft constrained to move along a straight-line path. By pivoting the shaft and attached connecting link, sector scanning motion of the transducer means is provided, and by simultaneously pivoting the connecting link and driving the upper end of the parallelogram linkage along said arcuate path, a compound linear-sector scanning transducer motion is provided.

Mechanical scanning method and apparatus for ultrasonic imaging, or the

There are disclosed radiation deflection method and means for controlling the direction of travel of radiation which is subject to refraction, such as light and sound radiation. The deflection method and means, which are particularly adapted for effecting a scanning motion of the radiation in one direction, include first and second generally counterrotating refracting wedges through which the radiation passes. The second wedge is mounted for rotation about a fixed axis and the first wedge is mounted for rotation about an axis which nutates about the fixed axis of rotation of the second wedge. Means are provided for rotating the first and second wedges in opposite rotary directions at equal angular displacements while simultaneously nutating said first wedge. For use with acoustic radiation a fluid filler medium is provided between the wedges, and a linear array of transducer elements is included over which the scanned compressional acoustic image field is swept by operation of the deflection system for converting the image field to an equivalent electrical signal. Novel wedge mounting and drive means are disclosed for the simultaneous rotation of the first wedge and nutational movement of the rotational axis thereof in the above described manner. The sum of the absolute amount of refraction of the radiation at the various interfaces of the system in passing through the system is minimized to substantially reduce mode conversion and aberration thereat.

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Palo Alto, CA, United States of America

Jon C Taenzer