RU1780860C - Ultrasonic focusing device - Google Patents

Description

(21) 4904183/10 (22) 01/22/91 (46) 12/15/92. Bull. No. 46 (72) V.G. Prokhorov and E.L. Kazmirovsky (56) Ultrasound. Little Encyclopedia / ed. I.I. Goal mine M .: Owls. Encyclopedias, 1979, p. 306-308.

USSR copyright certificate No. 920517, cl. G 01 N 29/04, 1980.

USSR Copyright Certificate No. 991656. cl. B 06 B 3/04, 1981.

USSR copyright certificate No. 879447, cl. G 01 N 29/04, 1980. (54) ULTRASONIC FOCUSING DEVICE

(57) Usage: ultrasound technique. SUMMARY OF THE INVENTION: The first radiating ephement is made in the form of a cylinder with annular sections, the thicknesses of which are selected in accordance with the dimensions of the Fresnel zones. The second radiating element is made in the form of a disk of coaxially arranged sections, the radial dimensions of which correspond to the sizes of the Fresnel zones. The second radiating element is mounted coaxially with the first radiating element at its end face through the decoupling insert. The external diameters of the radiating elements are equal, the foci are aligned at one point on the axis of symmetry of the device, and sound reflecting screens are located on the external surfaces of the radiating elements. 1 ill.

The invention relates to ultrasonic technology and can be used to focus ultrasonic vibrations when the ultrasonic force is applied to liquid and solid media, as well as in medical ultrasound diagnostics and therapy.

Focusing devices are known which consist of two main elements: an active emitter and a passive reflector. The reflector changes the direction of the wave incident on it in such a way that a concentration of energy of the reflected waves arises in a certain part of the space - this is the focal region.

Focusing devices that use flat and cylindrical zone reflectors in which neighboring zones are made of a mother (L

WITH

Ols with opposite reflection coefficients.

A disadvantage of these devices is the small emitting surface, determined by the size of the emitter, as well as losses due to re-reflection of ultrasonic waves from the reflector. The consequence of this is the low intensity of the ultrasound in focus.

The closest to the invention in technical essence and the achieved result is a device containing a radiating element made in the form of arc sections forming the surface of a half cylinder, the heights of which are selected in accordance with the dimensions of the Fresnel zones, and a sound-reflecting screen located on the outer surface of the radiating element.

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A disadvantage of such a device is the low radiation power at the focus due to the small size of the radiating surface.

The purpose of the invention is to increase the radiation power.

The goal is achieved in that the device is made in the form of two radiating elements. Moreover, the first radiating element is made in the form of a cylinder with annular sections, one of its ends is connected through a decoupling insert with a second radiating element in the form of a disk of coaxially arranged sections whose radial dimensions correspond to the sizes of the Fresnel zones. The first and second emitting elements are mounted coaxially, their external diameters are equal, the foci are aligned at one point on the axis of symmetry of the device, and on the outer surface of the second element there is an additional evacuation screen. The adjacent sections of both radiating elements have opposite oscillation directions due to the different polarization or phase of the supplied electrical voltages.

The drawing shows a longitudinal section of the device and the electrical connection diagram.

The ultrasonic focusing device comprises a cylindrical radiating element in the form of annular sections 1, whose heights correspond to the sizes of the Fresnel zones, a flat radiating element in the form of a disk from coaxially arranged sections 2, whose radial dimensions correspond to the sizes of the Fresnel zones, a sound-reflecting screen 3, supply electrodes 4 , The cylindrical element is connected to the disk element through the decoupling insert 5. The dimensions of both radiating elements are chosen so that their

the tricks are aligned at one point on the axis of symmetry of the device. The operation of the device is as follows.

When an exciting electric voltage is applied through the electrodes 4 to sections of the cylindrical 1 and plane 2 radiating elements, the cylindrical and plane waves emitted by these sections are converted into spherical, converging

in phase in a single focus F.

Thus, by increasing more than twice the area of the radiating surface while maintaining the size along the generatrix of the cylindrical element

Claims (1)

in comparison with the prototype, more than double the radiated power at the focus of the device is provided. SUMMARY OF THE INVENTION An ultrasonic focusing device comprising a first emitting element in the form of coaxially arranged sections, the thicknesses of which are selected in accordance with the dimensions of the Fresnel zones, and a sound-reflecting screen located on the outer surface of the first emitting element, characterized in that, in order to increase the radiation power , the first radiating element is made in. in the form of a cylinder with annular sections, one of its the ends are connected through a decoupling insert with a second radiating element inserted in the form of a disk of coaxially arranged sections whose radial dimensions correspond to the sizes of the zones Fresnel, the first and second radiating elements being installed coaxially, their external diameters are equal, the foci are aligned at one point on the axis of symmetry of the device, and on the outer surface of the second the radiating element is an additionally introduced evacuation screen.