Acoustics – Anatomic or prosthetic relation – Ear and mouth
Patent
1986-10-03
1989-08-01
Arnold, Bruce Y.
Acoustics
Anatomic or prosthetic relation
Ear and mouth
181142, 181176, 2504931, 372103, G02B 518, G10K 1132, H05H 302, G21G 400
Patent
active
048529737
ABSTRACT:
Arrangements are disclosed for generating a well defined traveling wave beam substantially unaffected by diffractive spreading. In different embodiments, the beam can be an electromagnetic wave, particle beam, a transverse beam, a longitudinal beam such as an acoustic beam, or any type of beam to which the Helmholtz generalized wave equation is applicable. Pursuant to the teachings herein, a beam is generated having a transverse dependence of a Bessel function, and a longitudinal dependence which is entirely in phaser form, which results in a beam having a substantial depth of field which is substantially unaffected by diffractive spreading. In first and second disclosed embodiments respectively, optical and acoustical beams are generated by placing a circular annular source of the beam in the focal plane of a focusing means, which results in the generation of a well defined beam thereby because the far field intensity pattern of an object is the Fourier transform thereof, and the Fourier transform of a Bessel function is a circular function. In a third disclosed embodiment, a microwave beam is generated by transmitting a coherent microwave beam sequentially through a phase modulator, having a periodic step function pattern, and a spatial filter, whose transmittance is the modulus of the Bessel function, to generate a microwave beam having a transverse Bessel function profile.
REFERENCES:
patent: 3230475 (1966-01-01), Koester et al.
patent: 4185254 (1980-01-01), Hall et al.
J. M. Stone, Radiation and Optics, published 1963-McGraw-Hill (New York), see p. 132 and FIGS. 7-16.
Goodman, J. W., Introduction to Fourier Optics, McGraw Hill, N.Y., 1968.
Wellford, W. T., "Use of Annular Apertures to Increase Focal Depth," Aug. 1960, JOSA, vol. 50, No. 8, pp. 749-753.
"Ultrasonic Transducer Design for Unfiorm Insonation in Biomedical Ultrasound", G. H. Garrison & E. K. Balcer-Kubiczek, 1985 Ultrasonics Symposium, pp. 630-633.
"Experimental Demonstration of Fourier Synthesis of an Annular Ultrasonic Intensity Distribution", G. H. Harrison & E. K. Balcer-Kubiczek.
"Annular and Sector Phased Array Applicators for Ultrasound Hypothermia", C. A. Cain & S. I. Umemura, 1985 Ultrasonics Symposium, pp. 936-941.
"Single-Transducer Electrode Design for Beam Shaping in Biomedical Ultrasound", G. H. Harrison & E. K. Balcer-Kubiczek, IEEE Transactions on Ultrasonics, Ferroelectrics & Frequency Control, vol. UFFC-33, No. 3, May 1986, pp. 265-272.
"Accoustical Imaging Techniques applied to General Transducer Design", G. H. Harrison, E. Balcer-Kubiczek & D. McCulloh, Acoustical Imaging, vol. 13 (1984).
Durnin James E.
Eberly Joseph H.
Arnold Bruce Y.
Research Corporation
LandOfFree
Diffraction free arrangement does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Diffraction free arrangement, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Diffraction free arrangement will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-127926