Non-contact ultrasound

About: Non-contact ultrasound is a research topic. Over the lifetime, 699 publications have been published within this topic receiving 11633 citations.

Noncontact Tactile Display Based on Radiation Pressure of Airborne Ultrasound

Abstract: This paper describes a tactile display which provides unrestricted tactile feedback in air without any mechanical contact. It controls ultrasound and produces a stress field in a 3D space. The principle is based on a nonlinear phenomenon of ultrasound: Acoustic radiation pressure. The fabricated prototype consists of 324 airborne ultrasound transducers, and the phase and intensity of each transducer are controlled individually to generate a focal point. The DC output force at the focal point is 16 mN and the diameter of the focal point is 20 mm. The prototype produces vibrations up to 1 kHz. An interaction system including the prototype is also introduced, which enables users to see and touch virtual objects.

Three-dimensional digital ultrasound tracking system

Abstract: A method and apparatus for simultaneous measurement of multiple distances by means of networked piezoelectric transducers Through the use of high frequency digital counters, the propagation delay between the activation of an ultrasonic transducer and the reception by similar transducers is quickly and accurately defined By alternating the duty cycle between transmit and receive modes, the system can track and triangulate the three-dimensional positions for each transducer

Method and system for wireless battery charging utilizing ultrasonic transducer array based beamforming

Abstract: An ultrasound power transmitter comprising a transmit ultrasonic transducer array has a plurality of transmit ultrasonic transducers. The ultrasound power transmitter activates a set of transmit ultrasonic transducers in close proximity of an electronic device to be arranged to beam ultrasound energy to the electronic device. Alignment magnets of the ultrasound power transmitter are aligned with corresponding alignment magnets of the electronic device to manage the ultrasound beaming. The ultrasound energy may be converted into electric power to charge the battery of the electronic device. Feedbacks may be provided by the electronic device to the ultrasound power transmitter to increase power transmission efficiency. The ultrasound power transmitter may pair the electronic device with other different electronic devices utilizing ultrasonic signals. A spacer with good ultrasound power transmission properties may be located between the ultrasound power transmitter and an ultrasound power receiver of an intended electronic device to enhance power transmission.

Apparatus and method for acoustic heat generation and hyperthermia

Abstract: An ultrasound hyperthermia applicator suitable for medical hyperthermia treatment, and method for using the same, includes two ultrasound sources (14, 16) producing focused ultrasound beams of frequencies f0 and f1. Aiming means direct the two ultrasound beams (20, 22) so that they cross each other confocally at the target. A controller (11) activates the two ultrasound sources so that the target is simultaneously irradiated by the two focused ultrasound beams. The two ultrasound sources provide acoustic energy sufficient to cause significant intermodulation products to be produced at the target due to the interaction of the two ultrasound beams. The intermodulation products are absorbed by the target to enhance heating of the target. In preferred embodiments the ultrasound sources include a pair of signal generators (34, 36) for producing gated ultrasound output signals driving single crystal ultrasound transducers (14, 16). In other embodiments the ultrasound sources include a pair of phased array ultrasound transducers for generating two steerable ultrasound beams. Aiming means are provided for electronically steering and focusing the two ultrasound beams so that they cross each other confocally at the target. Further embodiments employ pluralities of transducers, arrays, or both.

Ultrasound Transducers for Pulse-Echo Medical Imaging

Abstract: The transducer is probably the single most important component of any ultrasonic imaging system. A basic introduction to the problems and paradoxes of transducer design is given. After introducing the piezoelectric equations and discussing important transducer material such as lead zirconate titanate and polyvinylidene difluoride, the techniques for modeling the electromechanical impulse response are reviewed. Quarter-wave matching and short pulse techniques are discussed. The prediction of the ultrasound field of plane, spherical, and conical transducers is reviewed with emphasis on the spatio-temporal impulse response technique. Finally, the use of the above approaches is illustrated in a very practical fashion for three interesting transducer geometries: 1) a split aperture device with two focal lengths, 2) a five-element annular array, and 3) a 37.5 degree conical/annular array hybrid transducer.