US2427348A - Piezoelectric vibrator - Google Patents

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US2427348A
US2427348A US407456A US40745641A US2427348A US 2427348 A US2427348 A US 2427348A US 407456 A US407456 A US 407456A US 40745641 A US40745641 A US 40745641A US 2427348 A US2427348 A US 2427348A
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crystal
member
impedance
wave
energy
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US407456A
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Walter L Bond
Warren P Mason
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Nokia Bell Labs
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Nokia Bell Labs
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B06GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06BMETHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/06Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezo-electric effect or with electrostriction
    • B06B1/0644Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezo-electric effect or with electrostriction using a single piezo-electric element
    • B06B1/0662Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezo-electric effect or with electrostriction using a single piezo-electric element with an electrode on the sensitive surface
    • B06B1/067Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezo-electric effect or with electrostriction using a single piezo-electric element with an electrode on the sensitive surface which is used as, or combined with, an impedance matching layer
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S1/00Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
    • G01S1/72Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using ultrasonic, sonic or infrasonic waves
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S99/00Foods and beverages: apparatus
    • Y10S99/12Supersonic

Description

Sent '16, 1947;. w, L, BQN'D ETAL I 2,427,348 Y mw B1 E ua n, m1.. m l.%. C www. un .wr HF VFIC".

"ILSE um Leermcol/snc TMNS ` IFIER Mcm- AWSTAC MC WLBGND l By WI RMASN Paterited sept. 16, 1947 UNITED STATES PATENT OFFICE PIEZOELECTRIC VIBRATOR Walter L. Bond, South Orange, and Warren P. Mason, West Orange, N. J., assignprs to Bell Telephone Laboratories,

Incorporated, New

York, N. Y., a corporation of New York Application August 19, 1an, serial No."407,456

4 Claims.

stantially minimized and the efficiencies of the crystal and .the system in which it is employed yare increased.

It is known in the art to employ piezoelectric crystals to convert electrical wave energy into compressional (or acoustic) wave energy and the reverse.

In systems employing crystals in this manner, however, a number of difficulties have been encountered, among which are relatively low efdciency, echo effects resulting from reflections from the crystal surfaces, echo effects resulting from radiation by the crystal in directions other than a particular desired direction and unwanted resonant and transient effects in thevibratory response of the crystal.

It has been found that the above-mentioned and possibly additional undesirable effects largely result from or are aggravated by substantial acoustic impedance or compressional wave impedance differences between the crystal and the medium in which it is used.

The acoustic impedance or compressional wave impedance (Za) of a material is usually defined as the product of the velocity of propagation, V, of acoustic or compressional waves through the material and the density of the material p, i. e.,

Za=pV (1) For convenient reference representative values of the acoustic or compressional wave impedances for a number of materials which may be employed in systems illustrative of the principles of the invention are tabulated |below:

Material (c. g. s. units) Za=pV Methyl methacrylate 2.84X105 Polystyrene 2.64 X 105 Cellulose acetate 3.26X105 Moldedl phenol formaldehyde 3.75X105 Urea formaldehyde 4.2 X105 India ebony 4.4 X105 X-cut quartz 14.4 X105 Aluminum 13.8 X105 More par- Tungsten 83.0 X105 Water 1.44X105 Steel 40.0 X105 Rochelle salt 5.76X105 yKerosene 1.04Xl05 permalloy, 15% phenol formaldehyde1 12.8 X105 85% tungsten, 15% phenol formaldehyde1 14.0 X105. 30% permalloy, 70% phenol formaldehyde1 4.55X105 30% tungsten, 70% phenolformaldehyde1 4.55X105 1 Percentages given are by weight.

In systems employing piezoelectric crystals to radiate or receive acoustic or compressional waves in a liquid, steps should be taken to alleviate the effects of a mismatch of impedance between crystal and liquid.

This can best be done by inserting between the liquid and the crystal a layer of material having an acoustic or a compressional wave impedance which is substantially the geometric mean of the impedances of the crystal and the liquid, the thickness of the layer of material in the direction of propagation being substantially one-quarter wave-length of the frequency of the energy, or of the mean or predominant frequency where a band of frequencies is being propagated. An odd multiple of the quarter wave-lengths in thickness may be used provided the acoustic or compressional waveenergy absorption (or attenuation) of the material is not undesirably high.

Such a layer of material then acts as an impedance transformer and provides an improvement in the impedance match between the impedance of the crystal and that of th'e liquid and substantially reduces reflection losses therebetween and therefore materially reduces echo effects and similar undesirable reflective phenomenawhich can otherwise arise in many systems employing piezoelectric crystals in connection with compressional wave transmission systems.

By way of example, for a quartz crystal, having a compressional wave impedance of 14.4X c. g. s. units, immersed in water of 1.44X105 c. g. s. units impedance, a material having an acoustic impedance of 105 V 1.44 X 14.4=4.55 X 105 c. g. s. units should be interposed between the Crystal and the liquid.

Metals on thev other hand have W absorption and high compressional wave impedance but are highly conductive. v

It has been found possible to combine metals and plastics either in alternate layers or in the form of metallic particles suspended in a plas-` tic to obtain composite materials which will provide characteristics intermediate those of the constituent materials. For example, the plastic, phenol formaldehyde, with 30 per cent by weight ofV powdered Permalloy suspended therein (socalled 85 per cent Permalloy, i. e. 85 per cent Ni, per cent Fe, in alloy form, being used) has a compressional wave impedance of substantially 455x105 c. g. s. units which, as mentioned above, v

is suitable for a material to act as an impedance transforming layer between a quartz crystal and water. The material is, furthermore, electrically non-conductive and has a lower absorption than phenol formaldehyde alone.

For Rochelle salt piezoelectric crystals employed to radiate or absorb compressional waves in water, a material having a compressional wave impedance of 105 \/1.44 5.76=2.88 105 c. g. s. units should lbe interposed between the crystal and the water. From the tabulation given above it is seen that methyl methacrylate has substantially the desired compressional wave impedance. In this particular case the enclosure of the crystal should be moisture-proof since Rochelle salt is soluble in water.

In general, by suspending metallic particles in a plastic, as suggested previously, any compressional Wave impedance intermediate that of the plastic and that of the ,metal may be realized.v The acoustic impedance-varies directly with the proportion of metal to plastic in the composite material and the absorption ordissipation will vary inversely with the proportion of metal.

For systems in which a path through a liquid is included in the energy circuit `and piezoelectric crystals are used to introduce and abstract energy from the liquid, a liquid consisting of a mixture of water and alcohol, of water and ace-` tone or of water and ethylene glycol may be used. When the proper proportions of alcohol (12.5 volumes to 100 volumes of water), acetone (10.5 volumes to 100 volumes of water), or ethylene glycol (13 volumes to 100 volumes of water) are used the liquid will have, substantially, a zero coelcient of variation of velocity with temperature at 55 C. mean temperature as will be described in more detail hereinafter. For such systems phenol formaldehyde is a desirable plastic to use in the manufacture of impedance matching materials of the invention since it is not soluble in the liquids such as alcohol, acetone or ethylene glycol which it may be found desirable to use.

In many systems also it will be desirable to radiate or receive energy from only one side of the crystal in which case it is not only desirable to match the compressional .wave impedance on the radiating (or receivingy side of the crystal, but it is also desirable both to match the impedance and to provide for absorbing energy which reaches the opposite 0r passive side, either by virtue of the electrical drive on the crystal itself or by reception of direct or reflected energy from the medium in which the crystal is immersed. It should be noted that some of the energy received by the first-mentioned or active" side of the crystal will pass through the crystal to the opposite side and may cause objectionablev echoes unless the precautions, just described above, are taken.

A further advantage may under particular circumstances also be obtained by deliberately damping the crystal, where it is desired to employ crystals in pulse timing circuits since an undamped crystal generatesa pulse having its maximum amplitude near the center of the pulse whereas` a damped crystal will generate a pulse having maximumY amplitude near the. start of.y

the pulse. Reflections of the latter type of pulse are less likely to interfere with the directly transmitted or wanted pulse signals and also since the .timing is best done at the start of the pulse a very substantial improvement in operation and yide an improved compressional wave impedreflections of energy at the surfaces of a piezoelectric radiator or absorber surrounded by com` pressional wave conducting media.

Another object is to provide improved pulse timing piezoelectric crystal devices.

Other and further objects will become apparent during the course of the following description and in the appended claims.

The principles of the invention and a number of applications thereof will be more readily understood in connection with the following detailed description of illustrative embodiments shown in the accompanying drawings in which:

Fig. 1 shows a pair of piezoelectric crystals immersed in a liquid medium and provided with compressional wave impedance corrective front and back members;

Fig. 2 shows in detail a specific type of piezoelectric crystal mounting illustrating an application of certain principlesv of the invention;

Figs. 3A and 3B show wave trains representing compressional wave pulses which can be employed in piezoelectric crystal timing systems and will be employed in explaining advantages of particular arrangements of the invention;

Fig. 4 shows in block diagrammatic form a -simple pulse-type distance measuring system in which a unit of the general type illustrated by e Fig. 1 may be advantageously employed to assist in timing the reflected pulses; and

Fig. 5 illustrates the combination withl a crystal of a composite member comprising alternate layers of plastic and metallic material the composite member having particular impedance and damping properties to provide improved over-all operation of the piezoelectric crystal pulse timing arrangements of the invention.

In more detail. Fig. 1 shows two piezoelectric crystals Il one at the left end and the other at the right end o! a tank containing a liquid 3E therein. The crystals can be of any of the wellknown piezoelectric materials such as quartz, Rochelle salt or tourmaline. Conducting leads Ill and electrodes I2 provide means `for making appropriate electrical coupling with the crystals.

On the more central face oi each crystal a layer of material. member I4, is positioned. Member i4 can be, as was previously explained, an acoustic impedance transforming device to match the impedance of the crystal with that of the liquid andV it can further introduce energy absorption or damping of the crystal. if desired, as will be discussed presently. If impedance transformation alone i-s desired, the thickness of member I4 is preferably one-quarter wave-length (or a low odd number of one-quarterwave-lengths) of the frequency being transmitted through the liquid, or of the mid-frequency (or predominant frequency) if a group of frequencies is being transmitted. If Rochelle salt crystals are employed,

member I4 may be a simple plastic, for example,

methyl methacrylate, since a small impedance transformation will suffice. If the crystals employed are quartz, however, a larger transformation will be necessary and as was previously explained, member I4 can then comprise a plastic in which metal particles are suspended, for example, phenol formaldehyde with 30 per cent of powdered Permalloy (85 per cent Ni) to match quartz and water. Alternatively, member I4 may be a laminated member, alternate laminations being of plastic and of metal, respectively, as will be described in detail presently.

On the side of the crystal opposite member I4 in each case a member I6 is positioned, with a second member I8 adjacent the member I8 as shown in Fig. 1. Member I6 is similar to member i4 but its function is to match the compressional wave impedance of the crystal to that of the member I8 rather than to that of the liquid.

One of the possible constructions suggested for member I4 can obviously be selected for member I6 depending upon the particular impedance matching problem presented. Member I8 is an absorber of compressional wave energy, for example felt, the function of which is to absorb energy and thus prevent its reflection back to its associated crystal or to the crystal at the other end of the tank. Reilections or echoes are generally objectionable in communication or Vmeasuring circuits as they tend to distort or obscure the desired signals or to provide misleading signals and the substantial elimination at the .back sides of the crystals of reilections is highly desirable for many purposes.

In cases where it is desirable to exclude the liquid from direct contact with the crystal and associated impedance corrective and energy absorbing members. for example when Rochelle salt crystals soluble in water are used, a thin membrane oi' rubber or similar material can be employed to form a liquid tight envelope II without appreciably damping the action of the assembly. The effect of such a membrane from the standpoint of impedance, if appreciable, can be taken into account in the over-all design of the assembly.

Where the time of travel of a compressional wave, generated by one crystal in response to electrical stimulation, through the liquid 88 to the other crystal, is employed in timing some other phenomena. for example, the time interval required for an energy puise to travel to a distant surface and return to its point of origin, it is convenient to be able to adjust the distance between the crystals in tank 20. For this purpose, one crystal can be supported through a rotatable collar 28 on a rod 24 extending through a threaded bushing 28 in the side of tank 20. Rod 24 is threaded for the greater part of its length so that by turning knob 28, the longitudinal position of the crystal supported on rod .24 may be adjusted over an appropriate range. Knob 28 carries a suitable scale 21 and a slidable index pointer 28 carried on a fixed rod 25 is provided tofacilitate use of scale 21. A micrometer arrangement of any of the types well known in the art may be employed to afford precise adjustment, if desired.

As previously mentioned. three particularly suitable liquids for use in devices of the type illustrated by Fig. 1 are water with approximately 12.5 volumes of alcohol to 100 volumes of water, 10.5 volumes of acetone to 100 volumes of water, and 13 volumes of ethylene glycol to 100 volumes l of water. These liquids all have a zero temperature coeillcient of velocity at 55 C. vand a slow parabolic variation of velocity on either side of that, For example, a rough thermostat set to keepthe temperature to :6 C. will hold the velocity constant to one part in 3,000. Of these mixtures the one employing ethylene glycol is particularly advantageous since it will evaporate very slowly, and if the mixture is taken to 40 C. it will even then freeze in only a very mushy form which will not injure the apparatus. The respective velocities of these Vthree mixtures are alcohol-water. 1557 meters per second at 55 C.. acetone-water, 1565 meters per second and ethylene glycol-water 1594 meters per second.

The velocity of a three-component mixture containing alcohol, ethylene glycol and water can be made to vary from 1557 meters to 1594 meters by changing the relative proportion of alcohol and ethylene glycol and still maintain a zero coefllcient at 55 C. This is advantageous in matching the velocity of the liquid to standard screw threads in the variable delay circuit of Fig. l. This three-component mixture may also be employed to assist in the final adjustment of the impedance match between the piezoelectric devices and the liquid. An impedance change as great as 15 per cent can thus be effected.

In Fig. 2, details of a particular form of crystal mounting, embodying a number of principles of the invention, are shown,

Crystal 34, having electrodes 40 and conductive leads 38 to afford convenient electrical coupling thereto, is enclosed between members 36 and 32 which can be-of plastic material; for example methyl methacrylate, polystyrene, phenol formaldehyde, urea formaldehyde or the like, which may have suspended therein metallic particles in the event that it is desired to impart a greater compressional wave impedance to them. Member 32 in addition to forming part of the holder can also act as a compressione] wave impedance transformer and, if desired, -can also contribute compressional wave energy absorption. Members 86 and 42 can likewise be plastics, or plastics with metal particles suspended therein, or alternatively they can be of laminated construction with alternate laminae of plastic and metal, and member 44 is a compressional wave energy absorbing member, for example felt, the function of which is to absorb the energy reaching it. 'I'he assembly is held together by bolts 46 and nuts 41, which bolts may further serve to facilitate mounting the arrangement in operating position either in a tank such as 20 of Fig. 1 or on a vessel, buoy, or the like for use in submarine signaling systems. The assembly is preferably sealed to be liquid tight either by fusing th'e edges of theplastic members together by a hot iron where they come together or by enclosing the assembly in a thin membrane 43 of rubber or the like; If member 44 is of felt or other liquid absorbing material it will, of course, be necessary to enclose it, at least, in some liquid-proof enclosure, if it is to be submerged.

Where radiation or absorption from both sides of crystal 34 is desirable, members 42 and 44 can be omitted and members 32 and 36 can function as impedance transformer and/cr compressional wave damping means for the two sides oi.' the crystal. respectively, in substantially identical manners...

The curve 48 oi Fig. 3A indicates the amplitude response with time of an undamped piezoelectric crystal of the types contemplated for use in arrangements of the invention. Obviously, reflected echoes of an energy pulse resulting from such response, arriving a half pulse length or so in advance of a succeeding directly transmitted pulse can entirely mask the initial vibrations of the latter pulse and cause a false indication in pulse timing arrangements of the invention. However, if the crystal is damped, for example by placing in contact with it a material of relatively high compressional wave energy absorption (dissipation or resistance), its amplitude response can be changed to that represented by curve '50 of Fig, 3B, and combinations of echo pulses and directly transmitted pulses will in general produce indications which are distinguishable from single pulses of either type and (except where the two are in synchronism, or very nearly so) separate indications of the arrival of the two types of pulses can be obtained so that the likelihood of erroneous and misleading indications is substantially reduced. It is for this reason that it is under proper circumstances desirable to introduce absorption or loss in the auxiliary members associated with the crystal to damp its action as suggested in connection with Figs. 1 and 2 above.

In Fig. 4 a pulse-reflection type of distance measuring system is indicated in block diagram form. Oscillator 60 furnishes a sine wave to pulse generators 62 and 86 which generate one pulse for each cycle of the sine wave. Pulse amplifier 64 amplies the'pulses furnished by generator 62 and actuates electroacoustic transmitter 66, to send out a series of` acoustic pulses having the periodicity determined by the oscillator 6U. Obviously, this periodicity should be such that relected pulses from a. surface at the greatest distance to be measured will arrive back at acoustic receiver 18 before the next succeeding pulse is emitted by transmitter 66.

Reflections 'I4 of the pulses 10 from a distant surface 'l2 are received in electroacoustic receiver 18, converted into electrical pulses and applied to a vertical deflecting plate of cathode ray oscilloscope 80. The horizontal deflecting plates of the oscilloscope are connected to a sweep circuit 82 which furnishes, preferably, a saw-tooth wave deecting voltage which deects the ray of the oscilloscope across the target in synchronism with the emission of pulses by transmitter 66. Pulse generator 86 provides the liquid, adjustable, delay circuit 84 with a series of pulses which are in synchronism with the pulses of generator 62. The delay circuit output is supplied to the other vertical defiecting plate of the oscilloscope and the delay circuit is adjusted until the pulses furnished by it are in synchronism with the pulses furnished by receiver 1 The adjustment'of circuit 84 required to pr duce this synchronism is therefore a measure of the time of travel and therefore the distance traveled by the pulses to the reflecting surface 'l2l and back and the dial of the delay circuit can therefore be calibrated to read the distance directly.

Obviously, a radio transmitter and antenna and a radio receiver and antenna could be substituted for the corresponding acoustic transmitter and receiver, respectively, of Fig, 4. in which case the dial of the adjustable delay circuit should be calibrated in terms of the time of travel of electromagnetic waves, rather than acoustic waves.

Suitable apparatus units for all component apparatus of the system of Fig. 4 are well known to the art, whether acoustic or electromagnetic waves are employed, except for the adjustable delay circuit which is, of course', of the type described in detail above in connection with Fig. l.

For example, see copending application of D. Pollack, Serial No. 409,600, led September 5, 1941, entitled Phase and distance measuring systems, for a pulse reilection type of distance measuring circuit employing electromagnetic waves.

Fig. 5 illustrates in detail the method of building up a laminated member for use adjacent to a piezoelectric crystal for impedance matching and damping corrective purposes,

In Fig. 5 a piezoelectric crystal 54 has a backing comprising, layers of a plastic 52 and layers of a metal 56. The thickness of each layer is a wave-length of the frequency to be used, or of the mid-frequency of the band if a band of frequencies is to be used. Assuming radiation or reception of compressional wave energy from the back of the crystal is not desired, a layer of felt 44 or other absorbing material may be added at the left of the laminated member as shown in Fig.v 5. Where Zoi is the compressional wave impedance of the plastic used and Zoz is the impedance of the metal used, the effective impedance of the laminated structure, ZL, is given by the following equation:

The layer of plastic next to the crystal may, of course, be part of a box-like structure in which the crystal may be assembled as for the crystal of Fig. 2 and as suggested in connection with Fig. 2 the laminated structure may be member 42 of Fig. 2, a member 44 of felt or other absorbing material being added if no radiation or reception from that side of the crystal is desired. Member 44 is preferably enclosed in a thin membrane 5| of rubber or other moisture-proof material.

Numerous other arrangements embodying the principles of the invention and fairly within the scope thereof will occur to those skilled in the art. The scope of the invention is dened in the appended claims.

What is claimed is:

1. In an electrocompressional wave pulse transmission system, a device for converting energy of one type to energy of the other type comprising a piezoelectric crystal immersed in a duid having a substantially different impedance than the crystal, a member of material adjacent an emitting or 9 receiving side of said crystal, said member having an acoustic impedance intermediate that of said crystal and the said fluid, said intermediate impedance being substantially the geometric means of the crystal and fluid impedances, a second member of material adjacent the opposite side of said crystal having an impedance substantially the geometrical mean value between that of said crystal and a third member of energy absorbing material said third member being placed adjacent the second-mentioned member whereby energy is transferred between said crystal and said fluid with substantially no reection and energy reaching the said second member will be absorbed and troublesome reilectionsthereof will be eliminated.

2. A piezoelectric vibrator for submarine compressional wave signaling systems comprising a quartz crystal embedded in phenol formaldehyde, the phenol formaldehyde having in suspension therein 30 per cent by weight of Permalloy powder, whereby reflection of energy between the Avibrator and the water in which it is to be used will be substantially eliminated.

3. In a compressional wave pulse transmission system, a. sending and receiving device which comprises the combination of a piezoelectric vibrating member having a compressional-wave impedance exceeding that of the medium in which it is to be employed, a second member positioned against a vibrating surface of said piezoelectric member, said second member having a compressional-wave impedance substantially equal to the geometric mean of the compressional-wave impedances of said piezoelectric member and said medium, a third member positioned against the surface of said piezoelectric member opposite the first-stated vibrating surface and a fourthl member positioned adjacent the said third member, said third member having a compressional-wave impedance which is substantially equal to the geometric mean of the compressional-wave impedances of said piezoelectric member and said fourth member, said fourth member being of a Y material which absorbs substantially all compressional-wave energy reaching it, the energy absorption of said second, third and fourth members collectively being sufficient to dampen the response of said piezoelectric member to a pulse of energy so that .said response will be of maximum amplitude initially and will rapidly decrease, whereby unwanted reflections of energy in said system will be substantially reduced and interference from such unwanted reections as may occur will be far less troublesome.

4. In an. electrocompressional-wave delay circuit for use in pulse timing systems, said circuit being of the'type in which an electrical energy pulse is converted into a, compressional-wave energy pulse at a first point in a compressonalwave transmitting medium of known propagation characteristics and reconverted into an electrical energy pulse at a second point a. known distance from said rst point andthe time of ,travel of said pulse through said transmitting medium is employed as a standard of comparison by which the 10 pulse travel time of another pulse following a path of unknown length is measured, the combination of an electrocompressional-wave vibrating member having a compressional-wave impedance substantially different from the impedance of said medium, means adjacent one vibrating surface of said member for effecting an impedance match between said member and said medium, said means comprising a second member of a material having a compressional-wave irnpedance which is substantially the geometric mean of the impedance of said first-mentioned member and said medium, means adjacent a second surface of said first member for effecting the transfer of energy from said second surface without reflection therefrom and for absorbing suchenergy, said means comprising a third member placed adjacent the second surface of said rst member and substantially matching the impedance of said first-mentioned member and a fourth member of compressional-wave energy absorbing material placed adjacent said third member to absorb energy reaching said third member, and means for conditioning the response of said vibrating member to energy pulses to prov-ide response of initial maximum amplitude and rapidly decreasing amplitude, said laststated means comprising adequate `clamping properties4 in one or more of the said four members whereby unwanted reflections of the energy pulses in the delay circuitl are largely eliminated and the interfering properties of such unwanted reflections as may still be obtained are substantially reduced.

WALTER L. BOND. WARREN P. MASON.

REFERENCES CITED The following references are of record in the file of this patent:

UNrrED STATES PATENTS Number Name Date 2,138,036 Kunze Nov. 29, 1938 2,248,870 Langevin July 8, 1941 1,619,854 Crossley Mar. 8, 1927 1,732,029 Round Oct. 15, 1929 1,460,032 Moore June 26, 1923 2,263,902 Percival Nov. 25, 1941 2,283,285 Pohlman May 19, 1942 2,207,656 Cartwright et al July 9, 1940 1,677,945 Williams July 24, 1928 2,384,465 Harrison Sept. l1, 1945 FOREIGN PATENTS Number Country Date 174,355 Great Britain Mar. 8, 1923 466,212 Great Britain May 21, 1937 OTHER REFERENCES Page 223 of Handbook of Plastics by Simon'ds and Ellis. Fourth printing. D. Van Nostrand Co., 250 Fourth Ave., New York, N. Y. (Copy in Div. 15 of the U. S. Patent Oilice.)

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Cited By (70)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2481068A (en) * 1944-11-27 1949-09-06 Marconi Sounding Device Co Electroacoustic translator, including impedance matching
US2490452A (en) * 1946-08-16 1949-12-06 Bell Telephone Labor Inc Generation of transverse vibrations in liquids
US2515039A (en) * 1946-08-16 1950-07-11 Bell Telephone Labor Inc Transverse wave transmission in liquids
US2540720A (en) * 1945-08-01 1951-02-06 Forbes Gordon Donald Transmission line
US2567407A (en) * 1948-04-23 1951-09-11 Stromberg Carlson Co Electroacoustic transducer
US2569987A (en) * 1948-10-01 1951-10-02 Cambridge Thermionic Corp Pressure responsive transducer
US2591083A (en) * 1947-03-04 1952-04-01 Doehler Jarvis Corp Removal of flash, fin, and burr
US2605346A (en) * 1945-09-18 1952-07-29 Roland M Goglick Waterproof microphone
US2707755A (en) * 1950-07-20 1955-05-03 Sperry Prod Inc High absorption backings for ultrasonic crystals
US2711646A (en) * 1950-04-25 1955-06-28 Jean S Mendousse Acoustic impedance measuring device for liquids
US2727214A (en) * 1949-11-02 1955-12-13 Bell Telephone Labor Inc Acoustic delay line using solid rods
US2754238A (en) * 1951-05-22 1956-07-10 David L Arenberg Method of bonding and article thereby formed
US2754925A (en) * 1945-06-15 1956-07-17 Burke Thomas Finley Acoustic impedance element
US2826745A (en) * 1956-08-05 1958-03-11 Irving H Page Grid-type liquid delay line
US2913602A (en) * 1955-11-03 1959-11-17 Ivan L Joy Method and means for transmitting elastic waves
DE1110452B (en) * 1956-08-27 1961-07-06 Gen Ultrasonics Company Electromechanical ultrasonic generator
US3051927A (en) * 1960-08-04 1962-08-28 Texaco Inc Transducer assemblies
US3172078A (en) * 1959-01-27 1965-03-02 Texaco Inc Acoustic velocity well logging instrument
US3178681A (en) * 1960-01-07 1965-04-13 Rayflex Exploration Company Hydrophone
US3185868A (en) * 1962-05-28 1965-05-25 Forrest E Coyle Acoustic absorber pad
US3237150A (en) * 1961-02-24 1966-02-22 Curtiss Wright Corp Ultrasonic position indicator system
US3244253A (en) * 1959-12-23 1966-04-05 Schlumberger Well Surv Corp Acoustic logging systems
US3349608A (en) * 1964-11-03 1967-10-31 Bethlehem Steel Corp Ultrasonic thickness comparator device
US3376438A (en) * 1965-06-21 1968-04-02 Magnaflux Corp Piezoelectric ultrasonic transducer
US3555311A (en) * 1969-01-23 1971-01-12 Marquardt Corp High pressure piezoelectric transducer
US3663842A (en) * 1970-09-14 1972-05-16 North American Rockwell Elastomeric graded acoustic impedance coupling device
US3928777A (en) * 1974-08-26 1975-12-23 Dellorfano Jr Fred M Directional ultrasonic transducer with reduced secondary lobes
US3961305A (en) * 1975-02-14 1976-06-01 The United States Of America As Represented By The Secretary Of The Navy Fluid for filling sonar transducers
US4241995A (en) * 1977-12-28 1980-12-30 Nippon Kogaku K.K. Apparatus for measuring amount of displacement
US4771205A (en) * 1983-08-31 1988-09-13 U.S. Philips Corporation Ultrasound transducer
EP0589648A1 (en) * 1992-09-21 1994-03-30 Ngk Insulators, Ltd. Ultrasonic transducers
US6049159A (en) * 1997-10-06 2000-04-11 Albatros Technologies, Inc. Wideband acoustic transducer
EP1079119A3 (en) * 1999-08-26 2003-09-10 Kabushiki Kaisha Toyota Jidoshokki Position detecting device for hydraulic cylinder, and industrial vehicle equipped with the position detecting device
US20030192382A1 (en) * 2002-02-08 2003-10-16 Mueller Dennis William Acoustic coupling with a fluid retainer
US20030193267A1 (en) * 2002-02-08 2003-10-16 Mueller Dennis William Non-fluid acoustic coupling
US20040087670A1 (en) * 1999-10-21 2004-05-06 Lee Kang P. Rapid aerogel production process
US20070098857A1 (en) * 2003-05-26 2007-05-03 Rational Ag Method and device for determining physical characteristics
US20070208253A1 (en) * 1997-10-14 2007-09-06 Guided Therapy Systems, Inc. Imaging, therapy and temperature monitoring ultrasonic system
US20080214966A1 (en) * 2004-10-06 2008-09-04 Slayton Michael H Method and system for noninvasive face lifts and deep tissue tightening
US20080221491A1 (en) * 2004-09-16 2008-09-11 Guided Therapy Systems, Inc. Method and system for combined energy therapy profile
US20080281255A1 (en) * 2007-05-07 2008-11-13 Guided Therapy Systems, Llc. Methods and systems for modulating medicants using acoustic energy
US20080281237A1 (en) * 2007-05-07 2008-11-13 Guded Therapy Systems, Llc. Methods and systems for coupling and focusing acoustic energy using a coupler member
US20080294073A1 (en) * 2006-09-18 2008-11-27 Guided Therapy Systems, Inc. Method and sysem for non-ablative acne treatment and prevention
US20090216159A1 (en) * 2004-09-24 2009-08-27 Slayton Michael H Method and system for combined ultrasound treatment
US20090253988A1 (en) * 2004-10-06 2009-10-08 Slayton Michael H Method and system for noninvasive mastopexy
US20100160782A1 (en) * 2004-10-06 2010-06-24 Guided Therapy Systems, Llc Methods and systems for fat reduction and/or cellulite treatment
US20100241035A1 (en) * 2004-10-06 2010-09-23 Guided Therapy Systems, L.L.C. System and method for ultra-high frequency ultrasound treatment
US20100280420A1 (en) * 2004-09-16 2010-11-04 Guided Therapy Systems, Llc System and method for variable depth ultrasound treatment
US20110172530A1 (en) * 2000-12-28 2011-07-14 Ardent Sound, Inc. Visual imaging system for ultrasonic probe
US20110178444A1 (en) * 2009-11-24 2011-07-21 Slayton Michael H Methods and systems for generating thermal bubbles for improved ultrasound imaging and therapy
US8282554B2 (en) 2004-10-06 2012-10-09 Guided Therapy Systems, Llc Methods for treatment of sweat glands
US8366622B2 (en) 2004-10-06 2013-02-05 Guided Therapy Systems, Llc Treatment of sub-dermal regions for cosmetic effects
US8444562B2 (en) 2004-10-06 2013-05-21 Guided Therapy Systems, Llc System and method for treating muscle, tendon, ligament and cartilage tissue
US20130213714A1 (en) * 2012-02-21 2013-08-22 Baker Hughes Incorporated Acoustic synchronization system, assembly, and method
US8636665B2 (en) 2004-10-06 2014-01-28 Guided Therapy Systems, Llc Method and system for ultrasound treatment of fat
US8690779B2 (en) 2004-10-06 2014-04-08 Guided Therapy Systems, Llc Noninvasive aesthetic treatment for tightening tissue
US8858471B2 (en) 2011-07-10 2014-10-14 Guided Therapy Systems, Llc Methods and systems for ultrasound treatment
US8857438B2 (en) 2010-11-08 2014-10-14 Ulthera, Inc. Devices and methods for acoustic shielding
US8868958B2 (en) 2005-04-25 2014-10-21 Ardent Sound, Inc Method and system for enhancing computer peripheral safety
US8915870B2 (en) 2004-10-06 2014-12-23 Guided Therapy Systems, Llc Method and system for treating stretch marks
US9011337B2 (en) 2011-07-11 2015-04-21 Guided Therapy Systems, Llc Systems and methods for monitoring and controlling ultrasound power output and stability
US9114247B2 (en) 2004-09-16 2015-08-25 Guided Therapy Systems, Llc Method and system for ultrasound treatment with a multi-directional transducer
US9149658B2 (en) 2010-08-02 2015-10-06 Guided Therapy Systems, Llc Systems and methods for ultrasound treatment
WO2015180941A1 (en) * 2014-05-28 2015-12-03 Aktiebolaget Skf Couplant and arrangement of couplant, transducer, and construction component
US9263663B2 (en) 2012-04-13 2016-02-16 Ardent Sound, Inc. Method of making thick film transducer arrays
US20160139086A1 (en) * 2012-12-12 2016-05-19 Aktiebolaget Skf Couplant and arrangement of couplant, transducer, and construction component
US9504446B2 (en) 2010-08-02 2016-11-29 Guided Therapy Systems, Llc Systems and methods for coupling an ultrasound source to tissue
US9510802B2 (en) 2012-09-21 2016-12-06 Guided Therapy Systems, Llc Reflective ultrasound technology for dermatological treatments
US9694212B2 (en) 2004-10-06 2017-07-04 Guided Therapy Systems, Llc Method and system for ultrasound treatment of skin
US9827449B2 (en) 2004-10-06 2017-11-28 Guided Therapy Systems, L.L.C. Systems for treating skin laxity

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB174355A (en) * 1921-01-19 1923-03-08 Andre Eugene Blondel Improvements in or relating to the measurement of the time occupied by sound in travelling to and from a reflector
US1460032A (en) * 1923-06-26 X ew jeesey
US1619854A (en) * 1926-02-26 1927-03-08 Wired Radio Inc Piezo-electric-crystal apparatus
US1677945A (en) * 1924-06-20 1928-07-24 Submarine Signal Corp Method and apparatus for sound transmission
US1732029A (en) * 1924-07-16 1929-10-15 Rca Corp Acoustic instrument
GB466212A (en) * 1935-11-21 1937-05-21 Scophony Ltd Improvements in or relating to the generation of mechanical waves of supersonic frequency
US2138036A (en) * 1932-12-24 1938-11-29 Submarine Signal Co Compressional wave sender or receiver
US2207656A (en) * 1938-12-27 1940-07-09 Research Corp Process of decreasing reflection of light from surfaces, and articles so produced
US2248870A (en) * 1920-06-21 1941-07-08 Mauro And Lewis Piezoelectric signaling apparatus
US2263902A (en) * 1938-02-08 1941-11-25 Emi Ltd Delay device for use in transmission of oscillations
US2283285A (en) * 1938-05-25 1942-05-19 Pohlman Reimar Massage
US2384465A (en) * 1945-09-11 Submarine signaling appabatus

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1460032A (en) * 1923-06-26 X ew jeesey
US2384465A (en) * 1945-09-11 Submarine signaling appabatus
US2248870A (en) * 1920-06-21 1941-07-08 Mauro And Lewis Piezoelectric signaling apparatus
GB174355A (en) * 1921-01-19 1923-03-08 Andre Eugene Blondel Improvements in or relating to the measurement of the time occupied by sound in travelling to and from a reflector
US1677945A (en) * 1924-06-20 1928-07-24 Submarine Signal Corp Method and apparatus for sound transmission
US1732029A (en) * 1924-07-16 1929-10-15 Rca Corp Acoustic instrument
US1619854A (en) * 1926-02-26 1927-03-08 Wired Radio Inc Piezo-electric-crystal apparatus
US2138036A (en) * 1932-12-24 1938-11-29 Submarine Signal Co Compressional wave sender or receiver
GB466212A (en) * 1935-11-21 1937-05-21 Scophony Ltd Improvements in or relating to the generation of mechanical waves of supersonic frequency
US2263902A (en) * 1938-02-08 1941-11-25 Emi Ltd Delay device for use in transmission of oscillations
US2283285A (en) * 1938-05-25 1942-05-19 Pohlman Reimar Massage
US2207656A (en) * 1938-12-27 1940-07-09 Research Corp Process of decreasing reflection of light from surfaces, and articles so produced

Cited By (146)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2481068A (en) * 1944-11-27 1949-09-06 Marconi Sounding Device Co Electroacoustic translator, including impedance matching
US2754925A (en) * 1945-06-15 1956-07-17 Burke Thomas Finley Acoustic impedance element
US2540720A (en) * 1945-08-01 1951-02-06 Forbes Gordon Donald Transmission line
US2605346A (en) * 1945-09-18 1952-07-29 Roland M Goglick Waterproof microphone
US2490452A (en) * 1946-08-16 1949-12-06 Bell Telephone Labor Inc Generation of transverse vibrations in liquids
US2515039A (en) * 1946-08-16 1950-07-11 Bell Telephone Labor Inc Transverse wave transmission in liquids
US2591083A (en) * 1947-03-04 1952-04-01 Doehler Jarvis Corp Removal of flash, fin, and burr
US2567407A (en) * 1948-04-23 1951-09-11 Stromberg Carlson Co Electroacoustic transducer
US2569987A (en) * 1948-10-01 1951-10-02 Cambridge Thermionic Corp Pressure responsive transducer
US2727214A (en) * 1949-11-02 1955-12-13 Bell Telephone Labor Inc Acoustic delay line using solid rods
US2711646A (en) * 1950-04-25 1955-06-28 Jean S Mendousse Acoustic impedance measuring device for liquids
US2707755A (en) * 1950-07-20 1955-05-03 Sperry Prod Inc High absorption backings for ultrasonic crystals
US2754238A (en) * 1951-05-22 1956-07-10 David L Arenberg Method of bonding and article thereby formed
US2913602A (en) * 1955-11-03 1959-11-17 Ivan L Joy Method and means for transmitting elastic waves
US2826745A (en) * 1956-08-05 1958-03-11 Irving H Page Grid-type liquid delay line
DE1110452B (en) * 1956-08-27 1961-07-06 Gen Ultrasonics Company Electromechanical ultrasonic generator
US3172078A (en) * 1959-01-27 1965-03-02 Texaco Inc Acoustic velocity well logging instrument
US3244253A (en) * 1959-12-23 1966-04-05 Schlumberger Well Surv Corp Acoustic logging systems
US3178681A (en) * 1960-01-07 1965-04-13 Rayflex Exploration Company Hydrophone
US3051927A (en) * 1960-08-04 1962-08-28 Texaco Inc Transducer assemblies
US3237150A (en) * 1961-02-24 1966-02-22 Curtiss Wright Corp Ultrasonic position indicator system
US3185868A (en) * 1962-05-28 1965-05-25 Forrest E Coyle Acoustic absorber pad
US3349608A (en) * 1964-11-03 1967-10-31 Bethlehem Steel Corp Ultrasonic thickness comparator device
US3376438A (en) * 1965-06-21 1968-04-02 Magnaflux Corp Piezoelectric ultrasonic transducer
US3555311A (en) * 1969-01-23 1971-01-12 Marquardt Corp High pressure piezoelectric transducer
US3663842A (en) * 1970-09-14 1972-05-16 North American Rockwell Elastomeric graded acoustic impedance coupling device
US3928777A (en) * 1974-08-26 1975-12-23 Dellorfano Jr Fred M Directional ultrasonic transducer with reduced secondary lobes
US3961305A (en) * 1975-02-14 1976-06-01 The United States Of America As Represented By The Secretary Of The Navy Fluid for filling sonar transducers
US4241995A (en) * 1977-12-28 1980-12-30 Nippon Kogaku K.K. Apparatus for measuring amount of displacement
US4771205A (en) * 1983-08-31 1988-09-13 U.S. Philips Corporation Ultrasound transducer
EP0589648A1 (en) * 1992-09-21 1994-03-30 Ngk Insulators, Ltd. Ultrasonic transducers
US5446333A (en) * 1992-09-21 1995-08-29 Ngk Insulators, Ltd. Ultrasonic transducers
US6049159A (en) * 1997-10-06 2000-04-11 Albatros Technologies, Inc. Wideband acoustic transducer
US9272162B2 (en) 1997-10-14 2016-03-01 Guided Therapy Systems, Llc Imaging, therapy, and temperature monitoring ultrasonic method
US20070208253A1 (en) * 1997-10-14 2007-09-06 Guided Therapy Systems, Inc. Imaging, therapy and temperature monitoring ultrasonic system
US8480585B2 (en) 1997-10-14 2013-07-09 Guided Therapy Systems, Llc Imaging, therapy and temperature monitoring ultrasonic system and method
EP1079119A3 (en) * 1999-08-26 2003-09-10 Kabushiki Kaisha Toyota Jidoshokki Position detecting device for hydraulic cylinder, and industrial vehicle equipped with the position detecting device
US20040087670A1 (en) * 1999-10-21 2004-05-06 Lee Kang P. Rapid aerogel production process
US20110172530A1 (en) * 2000-12-28 2011-07-14 Ardent Sound, Inc. Visual imaging system for ultrasonic probe
US9907535B2 (en) 2000-12-28 2018-03-06 Ardent Sound, Inc. Visual imaging system for ultrasonic probe
US20050162041A9 (en) * 2002-02-08 2005-07-28 Mueller Dennis W. Non-fluid acoustic coupling
US6940212B2 (en) * 2002-02-08 2005-09-06 Metscan Technologies, Llc (A Georgia Limited Liability Corporation) Non-fluid acoustic coupling
US20050132811A1 (en) * 2002-02-08 2005-06-23 Mueller Dennis W. Scanning acoustic microscopy
US6973832B2 (en) 2002-02-08 2005-12-13 Metscan Technologies, Llc Acoustic coupling with a fluid bath
US6981418B1 (en) 2002-02-08 2006-01-03 Metscan Technologies, Llc Scanning acoustic microscopy
US7055389B2 (en) 2002-02-08 2006-06-06 Metscan Technologies, Llc Acoustic coupling with a fluid retainer
US7104132B2 (en) 2002-02-08 2006-09-12 Metscan Technologies, Llc Acoustic coupling with a fluid bath
US20050132810A1 (en) * 2002-02-08 2005-06-23 Mueller Dennis W. Non-fluid acoustic coupling
US20040182161A1 (en) * 2002-02-08 2004-09-23 Mueller Dennis William Acoustic coupling with a fluid bath
US20030193267A1 (en) * 2002-02-08 2003-10-16 Mueller Dennis William Non-fluid acoustic coupling
US20030192382A1 (en) * 2002-02-08 2003-10-16 Mueller Dennis William Acoustic coupling with a fluid retainer
US6951134B1 (en) 2002-02-08 2005-10-04 Metscan Technologies, Llc Flowing fluid acoustic coupling
US7234353B2 (en) 2002-02-08 2007-06-26 Metscan Technologies, Llc (A Georgia Limited Liability Corporation) Non-fluid acoustic coupling
US20070098857A1 (en) * 2003-05-26 2007-05-03 Rational Ag Method and device for determining physical characteristics
US20100280420A1 (en) * 2004-09-16 2010-11-04 Guided Therapy Systems, Llc System and method for variable depth ultrasound treatment
US9011336B2 (en) 2004-09-16 2015-04-21 Guided Therapy Systems, Llc Method and system for combined energy therapy profile
US20080221491A1 (en) * 2004-09-16 2008-09-11 Guided Therapy Systems, Inc. Method and system for combined energy therapy profile
US9114247B2 (en) 2004-09-16 2015-08-25 Guided Therapy Systems, Llc Method and system for ultrasound treatment with a multi-directional transducer
US8708935B2 (en) 2004-09-16 2014-04-29 Guided Therapy Systems, Llc System and method for variable depth ultrasound treatment
US10039938B2 (en) 2004-09-16 2018-08-07 Guided Therapy Systems, Llc System and method for variable depth ultrasound treatment
US9095697B2 (en) 2004-09-24 2015-08-04 Guided Therapy Systems, Llc Methods for preheating tissue for cosmetic treatment of the face and body
US9895560B2 (en) 2004-09-24 2018-02-20 Guided Therapy Systems, Llc Methods for rejuvenating skin by heating tissue for cosmetic treatment of the face and body
US10328289B2 (en) 2004-09-24 2019-06-25 Guided Therapy Systems, Llc Rejuvenating skin by heating tissue for cosmetic treatment of the face and body
US20090216159A1 (en) * 2004-09-24 2009-08-27 Slayton Michael H Method and system for combined ultrasound treatment
US9694211B2 (en) 2004-10-06 2017-07-04 Guided Therapy Systems, L.L.C. Systems for treating skin laxity
US8444562B2 (en) 2004-10-06 2013-05-21 Guided Therapy Systems, Llc System and method for treating muscle, tendon, ligament and cartilage tissue
US8460193B2 (en) 2004-10-06 2013-06-11 Guided Therapy Systems Llc System and method for ultra-high frequency ultrasound treatment
US8333700B1 (en) 2004-10-06 2012-12-18 Guided Therapy Systems, L.L.C. Methods for treatment of hyperhidrosis
US8506486B2 (en) 2004-10-06 2013-08-13 Guided Therapy Systems, Llc Ultrasound treatment of sub-dermal tissue for cosmetic effects
US10265550B2 (en) 2004-10-06 2019-04-23 Guided Therapy Systems, L.L.C. Ultrasound probe for treating skin laxity
US8523775B2 (en) 2004-10-06 2013-09-03 Guided Therapy Systems, Llc Energy based hyperhidrosis treatment
US8535228B2 (en) 2004-10-06 2013-09-17 Guided Therapy Systems, Llc Method and system for noninvasive face lifts and deep tissue tightening
US8636665B2 (en) 2004-10-06 2014-01-28 Guided Therapy Systems, Llc Method and system for ultrasound treatment of fat
US8282554B2 (en) 2004-10-06 2012-10-09 Guided Therapy Systems, Llc Methods for treatment of sweat glands
US8663112B2 (en) 2004-10-06 2014-03-04 Guided Therapy Systems, Llc Methods and systems for fat reduction and/or cellulite treatment
US8672848B2 (en) 2004-10-06 2014-03-18 Guided Therapy Systems, Llc Method and system for treating cellulite
US8690779B2 (en) 2004-10-06 2014-04-08 Guided Therapy Systems, Llc Noninvasive aesthetic treatment for tightening tissue
US8690780B2 (en) 2004-10-06 2014-04-08 Guided Therapy Systems, Llc Noninvasive tissue tightening for cosmetic effects
US8690778B2 (en) 2004-10-06 2014-04-08 Guided Therapy Systems, Llc Energy-based tissue tightening
US10252086B2 (en) 2004-10-06 2019-04-09 Guided Therapy Systems, Llc Ultrasound probe for treatment of skin
US10245450B2 (en) 2004-10-06 2019-04-02 Guided Therapy Systems, Llc Ultrasound probe for fat and cellulite reduction
US10238894B2 (en) 2004-10-06 2019-03-26 Guided Therapy Systems, L.L.C. Energy based fat reduction
US10046182B2 (en) 2004-10-06 2018-08-14 Guided Therapy Systems, Llc Methods for face and neck lifts
US10046181B2 (en) 2004-10-06 2018-08-14 Guided Therapy Systems, Llc Energy based hyperhidrosis treatment
US20080214966A1 (en) * 2004-10-06 2008-09-04 Slayton Michael H Method and system for noninvasive face lifts and deep tissue tightening
US8915870B2 (en) 2004-10-06 2014-12-23 Guided Therapy Systems, Llc Method and system for treating stretch marks
US8915853B2 (en) 2004-10-06 2014-12-23 Guided Therapy Systems, Llc Methods for face and neck lifts
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US8920324B2 (en) 2004-10-06 2014-12-30 Guided Therapy Systems, Llc Energy based fat reduction
US8932224B2 (en) 2004-10-06 2015-01-13 Guided Therapy Systems, Llc Energy based hyperhidrosis treatment
US10010721B2 (en) 2004-10-06 2018-07-03 Guided Therapy Systems, L.L.C. Energy based fat reduction
US8641622B2 (en) 2004-10-06 2014-02-04 Guided Therapy Systems, Llc Method and system for treating photoaged tissue
US10010726B2 (en) 2004-10-06 2018-07-03 Guided Therapy Systems, Llc Ultrasound probe for treatment of skin
US9039619B2 (en) 2004-10-06 2015-05-26 Guided Therapy Systems, L.L.C. Methods for treating skin laxity
US20100241035A1 (en) * 2004-10-06 2010-09-23 Guided Therapy Systems, L.L.C. System and method for ultra-high frequency ultrasound treatment
US20100160782A1 (en) * 2004-10-06 2010-06-24 Guided Therapy Systems, Llc Methods and systems for fat reduction and/or cellulite treatment
US10010724B2 (en) 2004-10-06 2018-07-03 Guided Therapy Systems, L.L.C. Ultrasound probe for treating skin laxity
US10010725B2 (en) 2004-10-06 2018-07-03 Guided Therapy Systems, Llc Ultrasound probe for fat and cellulite reduction
US9974982B2 (en) 2004-10-06 2018-05-22 Guided Therapy Systems, Llc System and method for noninvasive skin tightening
US9833639B2 (en) 2004-10-06 2017-12-05 Guided Therapy Systems, L.L.C. Energy based fat reduction
US20090253988A1 (en) * 2004-10-06 2009-10-08 Slayton Michael H Method and system for noninvasive mastopexy
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US9283410B2 (en) 2004-10-06 2016-03-15 Guided Therapy Systems, L.L.C. System and method for fat and cellulite reduction
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US9827450B2 (en) 2004-10-06 2017-11-28 Guided Therapy Systems, L.L.C. System and method for fat and cellulite reduction
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US9440096B2 (en) 2004-10-06 2016-09-13 Guided Therapy Systems, Llc Method and system for treating stretch marks
US9827449B2 (en) 2004-10-06 2017-11-28 Guided Therapy Systems, L.L.C. Systems for treating skin laxity
US9713731B2 (en) 2004-10-06 2017-07-25 Guided Therapy Systems, Llc Energy based fat reduction
US9707412B2 (en) 2004-10-06 2017-07-18 Guided Therapy Systems, Llc System and method for fat and cellulite reduction
US9522290B2 (en) 2004-10-06 2016-12-20 Guided Therapy Systems, Llc System and method for fat and cellulite reduction
US9533175B2 (en) 2004-10-06 2017-01-03 Guided Therapy Systems, Llc Energy based fat reduction
US9700340B2 (en) 2004-10-06 2017-07-11 Guided Therapy Systems, Llc System and method for ultra-high frequency ultrasound treatment
US9694212B2 (en) 2004-10-06 2017-07-04 Guided Therapy Systems, Llc Method and system for ultrasound treatment of skin
US9833640B2 (en) 2004-10-06 2017-12-05 Guided Therapy Systems, L.L.C. Method and system for ultrasound treatment of skin
US8868958B2 (en) 2005-04-25 2014-10-21 Ardent Sound, Inc Method and system for enhancing computer peripheral safety
US20080294073A1 (en) * 2006-09-18 2008-11-27 Guided Therapy Systems, Inc. Method and sysem for non-ablative acne treatment and prevention
US9566454B2 (en) 2006-09-18 2017-02-14 Guided Therapy Systems, Llc Method and sysem for non-ablative acne treatment and prevention
US8764687B2 (en) 2007-05-07 2014-07-01 Guided Therapy Systems, Llc Methods and systems for coupling and focusing acoustic energy using a coupler member
US9216276B2 (en) 2007-05-07 2015-12-22 Guided Therapy Systems, Llc Methods and systems for modulating medicants using acoustic energy
US20080281255A1 (en) * 2007-05-07 2008-11-13 Guided Therapy Systems, Llc. Methods and systems for modulating medicants using acoustic energy
US20080281237A1 (en) * 2007-05-07 2008-11-13 Guded Therapy Systems, Llc. Methods and systems for coupling and focusing acoustic energy using a coupler member
US9345910B2 (en) 2009-11-24 2016-05-24 Guided Therapy Systems Llc Methods and systems for generating thermal bubbles for improved ultrasound imaging and therapy
US9039617B2 (en) 2009-11-24 2015-05-26 Guided Therapy Systems, Llc Methods and systems for generating thermal bubbles for improved ultrasound imaging and therapy
US20110178444A1 (en) * 2009-11-24 2011-07-21 Slayton Michael H Methods and systems for generating thermal bubbles for improved ultrasound imaging and therapy
US8715186B2 (en) 2009-11-24 2014-05-06 Guided Therapy Systems, Llc Methods and systems for generating thermal bubbles for improved ultrasound imaging and therapy
US10183182B2 (en) 2010-08-02 2019-01-22 Guided Therapy Systems, Llc Methods and systems for treating plantar fascia
US9504446B2 (en) 2010-08-02 2016-11-29 Guided Therapy Systems, Llc Systems and methods for coupling an ultrasound source to tissue
US9149658B2 (en) 2010-08-02 2015-10-06 Guided Therapy Systems, Llc Systems and methods for ultrasound treatment
US8857438B2 (en) 2010-11-08 2014-10-14 Ulthera, Inc. Devices and methods for acoustic shielding
US9452302B2 (en) 2011-07-10 2016-09-27 Guided Therapy Systems, Llc Systems and methods for accelerating healing of implanted material and/or native tissue
US8858471B2 (en) 2011-07-10 2014-10-14 Guided Therapy Systems, Llc Methods and systems for ultrasound treatment
US9011337B2 (en) 2011-07-11 2015-04-21 Guided Therapy Systems, Llc Systems and methods for monitoring and controlling ultrasound power output and stability
US20130213714A1 (en) * 2012-02-21 2013-08-22 Baker Hughes Incorporated Acoustic synchronization system, assembly, and method
US9618646B2 (en) * 2012-02-21 2017-04-11 Bakery Hughes Incorporated Acoustic synchronization system, assembly, and method
US9263663B2 (en) 2012-04-13 2016-02-16 Ardent Sound, Inc. Method of making thick film transducer arrays
US9510802B2 (en) 2012-09-21 2016-12-06 Guided Therapy Systems, Llc Reflective ultrasound technology for dermatological treatments
US9802063B2 (en) 2012-09-21 2017-10-31 Guided Therapy Systems, Llc Reflective ultrasound technology for dermatological treatments
US10119943B2 (en) * 2012-12-12 2018-11-06 Aktiebolaget Skf Couplant and arrangement of couplant, transducer, and construction component
US20160139086A1 (en) * 2012-12-12 2016-05-19 Aktiebolaget Skf Couplant and arrangement of couplant, transducer, and construction component
WO2015180941A1 (en) * 2014-05-28 2015-12-03 Aktiebolaget Skf Couplant and arrangement of couplant, transducer, and construction component
CN106471366A (en) * 2014-05-28 2017-03-01 斯凯孚公司 Couplant and arrangement of couplant, transducer, and construction component
US20170176398A1 (en) * 2014-05-28 2017-06-22 Aktiebolaget Skf Couplant and arrangement of couplant, transducer, and construction component

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