DE10347079B4 - Coupler arrangement for an ultrasound device and ultrasound method - Google Patents

Abstract

Coupler arrangement (1) for coupling and / or decoupling ultrasonic waves, in particular in an ultrasound device, with
at least one elongated waveguide (2) for guiding the ultrasonic waves and
at least one electro-acoustic transducer (4), which is coupled laterally to the waveguide (2) and has a piezoceramic, for generating and / or detecting the ultrasonic waves,
characterized in that
the piezoceramic for generating ultrasonic waves with a first vibration mode with a first frequency can be excited to transverse-strain oscillations and for generating ultrasonic waves with the first or a second vibration mode with a second frequency to thickness-stretching vibrations can be excited.

Description

The The invention relates to a coupler arrangement for coupling and / or decoupling ultrasonic waves, in particular in an ultrasound device, according to the preamble of the claim 1 and an ultrasonic method according to the preamble of the claim 21st

Out US 3,584,327 and US 3,825,887 Coupler arrangements are known which can be used in an ultrasonic device to couple ultrasonic waves into a measurement or processing object. These known coupler arrangements have a waveguide with numerous fibers for guiding the ultrasonic waves to be injected, wherein the ultrasound is coupled in at an end face of the waveguide by an electroacoustic transducer into the individual fibers of the waveguide. In the waveguide, the coupled-in ultrasonic waves are then continued in the form of the simplest mode to the distal end of the waveguide, where they are coupled into the measurement or processing object.

adversely in these known coupler arrangements, the poor efficiency in the coupling of the ultrasonic waves of the electro-acoustic Transducer in the waveguide, so that at frequencies above of 100 kHz, only relatively low ultrasonic powers in the waveguide can be coupled.

Furthermore, it is off DE 199 21 279 C1 a surgical ultrasonic device for bone processing is known, in which during the processing of a bone ultrasonic waves are radiated into the bone Chen and the backscattered or reflected ultrasonic radiation is evaluated to assess the nature of the bone material.

adversely in this known surgical ultrasound device is the relatively low significance in the evaluation of the back scattered or reflected ultrasonic radiation as a model homogeneous structure of the examined bone material presupposed becomes. However, many measurement objects, such as bones, have a complicated heterogeneous structure, resulting in the evaluation of the backscattered and reflected ultrasonic waves difficult.

In U.S. 5,509,417 discloses a device which discloses a plurality of laterally mounted on an ultrasonic waveguide transducers to produce by a suitable phase control of the sound transducer, a sound wave in the sound waveguide.

The US 5,400,788 also discloses an apparatus for generating a sound wave in a sound waveguide, wherein it is proposed to generate with several piezo elements sound waves of different frequencies in an acoustic waveguide.

In DE 41 03 145 A1 It is proposed to provide a directional head with several separate ultrasonic transducers.

The DE 102 19 297 A1 discloses an apparatus for generating electromagnetic energy and ultrasonic energy to form two-dimensional hub structures.

In US 3 468 517 An apparatus for transmitting sound and ultrasonic waves to a surface is disclosed.

Of the The invention is therefore based on the object described above known coupler arrangements for ultrasound equipment to improve that even at higher frequencies of, for example more than 100 kHz satisfactory ultrasonic power in a measuring or processing object can be coupled, preferably different Vibration modes or different types of waves can be used.

Farther The invention is based on the object, an ultrasonic method to create, even in the investigation of measurement objects with complicated heterogeneous internal structures provides satisfactory results.

These Tasks are achieved by a coupler arrangement according to claim 1 and an ultrasonic method according to claim 21 solved.

The The invention is based on the recognition that the small end face of the Waveguide in the conventional Coupler arrangement in the axial direction only a small acoustic load for the electro-acoustic transducer forms, resulting in the ineffective coupling the limited to the simplest vibration mode ultrasonic waves leads.

The The invention therefore comprises the general technical teaching, the electro-acoustic Coupling transducer laterally to the waveguide, whereby the effective contact area between the transducer and the waveguide compared to the end face of the Waveguide can be significantly increased.

The lateral coupling of the elektro-akusti not only allows an increase in the effective contact surface, but also allows an improvement of the coupling factor, since a two-dimensional coupling is possible.

In A variant of the invention are several along the waveguide electro-acoustic transducers each side of the waveguide coupled, whereby the coupled ultrasonic power can be further increased can.

In an embodiment In this variant, the adjacent transducers each have the same direction of polarization on and are in the longitudinal direction of the Waveguide equidistant arranged at a distance that is substantially equal to the wavelength of the Ultrasonic waves in the waveguide is. This arrangement of the individual Transducer at a given distance is required for it to move the ultrasonic waves coupled in by the individual transducers in the waveguide positively overlay and do not obliterate.

Preferably The transducers in the waveguide generate ultrasonic waves first vibration mode having a first wavelength and a first frequency and ultrasonic waves of a first or second vibration mode with a second wavelength and one opposite the first frequency larger second Frequency, where the number of transducers is less than or equal to half Quotient of the second frequency and the first frequency is. This limitation of the number of transducers makes sense, since the total length of the in a row along the waveguide arranged transducer half wavelength do not exceed the first mode of vibration in the waveguide should.

The above-described generation of ultrasonic waves with different Vibration modes and frequencies is advantageous because the different Vibration modes and wavelengths associated with different physical benefits are that can be combined with each other.

Thus, the ultrasonic waves of the first vibration mode, for example in the form of the symmetric S ₀ mode of the lambda wave (strain wave) have a frequency in the range of 200 kHz to 0.9 MHz. An advantage of ultrasonic waves with such a low frequency below the cut-off frequency of the measurement object is the fact that they propagate in the solid phase of the measurement object and have a correspondingly large penetration depth due to the relatively large wavelength. A disadvantage of the relatively large wavelength of such ultrasonic waves, in contrast, that the spatial resolution is correspondingly low, while the dead zone, in the superposition of the received and emitted ultrasonic signal, a determination of interfaces is impossible, is relatively large.

In contrast, the yourself in the liquid Phase propagating ultrasonic waves of the first or second mode vibration For example, a frequency in the range of 0.9 MHz to 3 MHz and have a correspondingly smaller wavelength, so that these ultrasonic waves only in the liquid phase of the measurement object can spread and have a lower penetration depth. This is an advantage over that the death zone smaller and the spatial resolution due to the lower wavelength is correspondingly larger.

in this connection we understand one below the cut-off frequency of the DUT Value of the frequency below which the propagation of the ultrasonic waves enabled by the solid phase and, above that, the propagation of the ultrasonic waves is blocked by the solid phase. In this case, the ultrasonic waves through the surface the solid phase into the liquid Radiated phase in which they spread and become more scattered.

By a combination of ultrasonic waves propagating in the solid phase with oneself in the liquid Phase propagating ultrasonic waves can thus have the advantages of great penetration combined with the advantages of a smaller dead zone and a larger spatial resolution become.

In Another variant of the invention, along the waveguide arranged transducers, however, in each case opposite polarization directions on and are in the longitudinal direction of the waveguide equidistant arranged at a distance that is substantially equal to half wavelength the ultrasonic waves in the waveguide is. Again, this is the arrangement of the transducers at a given distance important, so that the coupled from the individual transducers in the waveguide Superimposing ultrasonic waves in the waveguide positive and not cancel.

Also In this variant of the invention, it is advantageous if the transducers in the waveguide ultrasonic waves of a first vibration mode with a first wavelength and a first frequency and ultrasonic waves of one of the first or second vibration mode having a second wavelength and one opposite the first frequency larger second Generate frequencies, the number of transducers preferably smaller or equal to the quotient of the second frequency and the first Frequency is.

The Generation of the ultrasonic waves of the first vibration mode with the first frequency and the first or second vibration mode with The second frequency is carried out according to the invention by an electro-acoustic Converter. For this purpose, the electro-acoustic transducer preferably a piezoceramic, which is used to generate the ultrasonic waves the first frequency is excitable to transverse strain oscillations and for generating the ultrasonic waves at the second frequency Thickness-extensional vibrations can be excited.

It however, it is also possible as an alternative that the transducer ultrasonic radiation broadband in the measuring or Coupled processing object, wherein the ultrasonic waves first in the measurement or processing object due to the interaction between the coupled broadband ultrasonic radiation and form the measurement or processing object.

In In this case, the low-frequency propagate below the cut-off frequency Part of the broadband spectrum (through) in the solid phase and the above the cutoff frequency high-frequency part of this broadband Spectrum in the liquid Phase of the DUT off.

In a preferred embodiment According to the invention, the waveguide of the coupler arrangement has several Fibers, the transducers each side of the individual Fibers or groups of fibers are coupled. In such a mehrfaserigen training of the waveguide comes the advantage of lateral according to the invention Coupling of the transducer particularly for carrying, since the face of the individual fibers of the waveguide with the radius decreases quadratically, while the lateral surface the individual fibers with the radius decreases only linearly. Also at very thin Fibers reaches the lateral surface the fibers so mostly still to the desired ultrasonic power coupled into the fibers, whereas the end face of the fibers due to the small radius is no longer sufficient.

at a coupler arrangement according to the invention with a multi-fiber waveguide, the lateral coupling of electroacoustic transducers to the individual fibers of the waveguide for reasons of space to be difficult. Preferably, the individual fibers of the waveguide stand therefore at the proximal end of the waveguide with respect to the longitudinal direction of the waveguide star shape off so that the proximal ends of each fiber of the waveguide easily accessible are and a simple coupling of electro-acoustic transducers enable.

Furthermore exists within the scope of the invention, the possibility that the individual Fibers of the waveguide at least partially different sound propagation velocities exhibit. This can be advantageous, for example, if the individual Fibers of different lengths have so that the at the distal end of the waveguide of the individual Fibers emitted ultrasound waves the desired phase relationship to each other exhibit. About that In addition, the wave conductor by a suitable design of the Sound propagation velocity in individual fibers of the waveguide also assume the function of an acoustic lens, so that the at the distal End of the waveguide emitted ultrasonic radiation in a given Focus point is focused.

When using the coupler arrangement according to the invention in an ultrasound device for material processing, the waveguide may have a distal end which is rotationally symmetrical with respect to the longitudinal direction of the waveguide, as in the case of the cited publication DE 199 21 279 C1 the case is.

It Alternatively, there is also the possibility that the distal Spherical end of waveguide, is conical or concave shaped. However, the invention is in terms of the shaping of the distal end of the waveguide not on the mentioned above Limited geometries, but also feasible in other ways.

Farther is to mention that in the coupler arrangement according to the invention between the transducer and the waveguide or the individual fibers the waveguide as coupling agent preferably a silver conductive adhesive or an adaptation layer is arranged.

Furthermore is to mention that the converter consist for example of two or more parts can, between which the waveguide or one or more fibers the waveguide are arranged, wherein between the parts of the Transducer and the fibers of the waveguide or the waveguide a touch contact exists, allowing vibrations from the transducer to the waveguide or its fibers transmitted can be. For example can the parts of the converter are plan parallel plates between which the waveguide or fibers of the waveguide are pressed.

alternative is possible, too, that the transducer, the waveguide or individual fibers of the waveguide annular surrounds, wherein the converter can be divided into several segments, the above the circumference of the waveguide are distributed.

It should also be noted that the waveguide optionally made of a flexible material or may be made of a rigid material such as aluminum, alumina, titanium, stainless steel or other metals or oxides.

Moreover, the invention is not limited to the above-described coupler arrangement according to the invention as an independent component. Rather, the invention also encompasses an ultrasound device, in particular a medical diagnostic or therapeutic device or a material processing or testing device of such a coupler arrangement. In this regard, reference is made by way of example to a possible use of the coupler arrangement according to the invention in a surgical tool, as described in the publication already cited above DE 199 21 279 C1 is described.

Farther For example, the invention also includes an ultrasound method using the above-described coupler arrangement according to the invention carried out can be.

in this connection ultrasonic waves of a first frequency, which is below the cutoff frequency of the measurement object, and ultrasonic waves a second frequency that is above the cutoff frequency of the DUT is generated.

in this connection have the ultrasonic waves of the first frequency a corresponding larger wavelength as the ultrasonic waves of the second frequency. By this generation of ultrasonic waves of different wavelengths, the advantage of a larger spatial resolution of Ultrasonic waves with the short wavelength with the advantage of a larger penetration depth which combines ultrasonic waves with the longer wavelength become. In the measurement object, the ultrasonic waves are then scattered back and / or reflected, with the back scattered or reflected ultrasonic waves detected and evaluated become. In the evaluation of the backscattered or reflected Ultrasonic waves can be the intensity and / or the transit time and / or the frequency spectrum and / or associated information (e.g. STFA - Short-Time Frequency Analysis or SSP - Split Spectrum Processing) the detected ultrasonic waves are evaluated.

in this connection For example, in the first frequency of the ultrasonic waves Range from 200 kHz to 0.9 MHz, while the second frequency of the ultrasonic waves for example, in the range between 0.9 MHz to 3 MHz. These frequencies have been found in the study of bone substance (Cancellous bone and cortex) proved to be beneficial. As part of the Invention can however basically also used other frequencies dependent on the cutoff frequency become.

In In a variant of the invention, the ultrasonic waves become common coupled by a broadband ultrasonic radiation in the measurement object, wherein the ultrasonic waves of the first frequency and the ultrasonic waves the second frequency due to the interaction of the coupled broadband Form ultrasonic radiation with the measurement object. Preferably has the coupled broadband ultrasonic radiation here a center frequency that is larger as the frequency of propagating in the liquid phase Ultrasonic waves, so for example above 3 MHz. The However, coupled ultrasonic frequency can also above the upper frequency and / or between the operating frequencies and for example, be 2 MHz. The bandwidth should be different Include frequencies.

In another variant of the ultrasonic method according to the invention the ultrasonic waves propagating in the solid phase of the first Frequency and in the liquid In contrast, phase propagating ultrasonic waves of the second frequency separated from each other by ultrasonic radiation with different Center frequencies coupled into the DUT.

Furthermore is preferably a dynamic focus of the in the measurement object coupled ultrasonic waves provided so that they in the Measuring object can be focused on a predetermined focus. For this is preferably a plurality of ultrasonic waves spatially distributed coupled into the measurement object, wherein the phase angle and / or the Delay Time the individual ultrasonic waves are set separately from each other is going to be the spatial Determine the position of the focus of the ultrasonic waves in the measurement object. For this purpose, for example, the above-described coupler arrangement according to the invention be used with a multi-fiber waveguide, wherein the individual fibers of the waveguide independently controlled to set the focus accordingly.

Preferably becomes the spatial Location of the focus of the ultrasonic waves in the measurement object here in dependence from the evaluation of the intensity and / or the transit time and / or the frequency spectrum of the detected ultrasonic waves established. It is advantageous if the spatial Location of the focus in dependence of distribution function of the delay times the ultrasonic waves generated and received in each waveguide is determined. Preferably, the spatial position of the focus in the measurement object dependent on determined from the speed of sound, resulting from previous ones Measurements or the literature results.

In the context of the invention Ultra sound method can be determined by an evaluation of the intensity and / or the transit time and / or the frequency spectrum and the frequency spectrum of the detected ultrasonic waves, the spatial position of an interface in the measurement object, wherein the focus of the ultrasonic waves is set in the measurement object on the interface.

Especially Advantageously, the ultrasonic method according to the invention is suitable for Examination of a bone with a cortex and cancellous bone. Other advantageous developments of the invention are characterized in the subclaims or will be discussed below together with the description of the preferred Embodiments of the Invention with reference to the figures explained. Show it:

1 a coupler arrangement according to the invention with a multi-fiber waveguide for an ultrasound device,

2 a plan view of the coupler arrangement 1 .

3a and 3b various arrangements of electroacoustic transducers on the waveguide of the coupler arrangement,

4a to 4d different geometries of the distal end of the coupler assembly 1 .

5a to 5e various possible arrangements of an electro-acoustic transducer on a fiber of the waveguide of the coupler arrangement,

6 a coupler arrangement according to the invention in the processing of a bone.

The 1 and 2 show a coupler arrangement according to the invention 1 for an ultrasound device in order to couple ultrasound waves into a measurement object or to decouple them from the measurement object.

For this purpose, the coupler arrangement 1 a multi-fiber waveguide 2 on, made of numerous fibers 3 which is at the proximal ends of the individual fibers 3 of the waveguide 2 in each case several electro-acoustic transducers 4 are coupled, the ultrasonic waves in the waveguide 2 inject.

The proximal ends of the individual fibers 3 of the waveguide 2 stand here with respect to the longitudinal axis of the waveguide 2 star-shaped, as in particular from 2 is apparent. This way, between the individual fibers 3 of the waveguide 2 at the proximal end of the waveguide 2 Space for attaching the electro-acoustic transducer 4 created.

Of particular importance here is that the individual electro-acoustic transducer 4 each side of the lateral surface of the individual fibers 3 of the waveguide 2 are coupled. This lateral coupling of the electro-acoustic transducer 4 offers over a conventional end face side coupling the advantage of a larger contact area between the electro-acoustic transducers 4 and the fibers 3 of the waveguide 2 , which contributes to a more effective coupling and allows the coupling of a larger ultrasonic power.

This is additionally supported by that to every fiber 3 of the waveguide three electro-acoustic transducer 4 coupled, which allows the coupling of larger power.

In the embodiment shown here, the waveguide 2 at its distal end a spherically shaped tip 5 on. This rotationally symmetrical configuration of the tip 5 allows rotation of the waveguide 2 in an ultrasonic device, as for example in the cited publication DE 199 21 279 C1 the case is.

3a shows an embodiment of a possible arrangement of the electro-acoustic transducer 4 at the proximal end of the individual fibers 3 of the waveguide 2 , In this embodiment, the individual electro-acoustic transducers 4 in each case the same direction of polarization, wherein the electro-acoustic transducer 4 along the fiber 3 are arranged at a constant distance from each other, which is equal to the wavelength λ of the coupled ultrasonic waves. This arrangement of the electro-acoustic transducer 4 along the fiber 3 at a given distance is important to keep up with the electro-acoustic transducers 4 positively superimpose coupled ultrasonic waves.

3b shows an alternative embodiment of an arrangement of electro-acoustic transducers 4 ' on a fiber 3 ' , This embodiment is largely consistent with that described above and in 3a illustrated embodiment, so that the same reference numerals are used for corresponding components, which are characterized only to avoid repetition by an apostrophe.

A special feature of this embodiment is that the individual electro-acoustic transducer 4 ' have alternately different polarization directions, as can be seen from the oppositely directed arrows. Ent speaking are the adjacent electro-acoustic transducers 4 ' each arranged at a distance from each other, which is equal to half the wavelength (or an integer multiple thereof) in the fiber 3 ' coupled ultrasonic waves is. This arrangement of the electro-acoustic transducer 4 ' At a given distance, in turn, it is necessary to keep up with the individual electro-acoustic transducers 4 ' coupled ultrasonic waves in the fiber 3 ' positively superimpose and not extinguish.

The 4a to 4d show different geometries of the top 5 of the waveguide 2 , in which 4d in the 1 Spherical geometry of the tip already shown 5 reproduces.

4a on the other hand shows a concave tip 5 ' whereas the 4b and 4c tapered pointed tips 5 '' respectively. 5 ''' demonstrate. The tips 5 '' and 5 ''' in the 4b and 4c differ here only by the respective cone angle, the tip 5 ''' more acute than the tip 5 ' ,

5a shows a cross section 3a through the fiber 3 in the region of the electro-acoustic transducer 4 , From this representation it can be seen that the electro-acoustic transducer 4 in this embodiment of two plane-parallel plates 6 . 7 between which the fiber exists 3 is pressed, wherein the plane-parallel plates 6 . 7 of the electroacoustic transducer 4 on the lateral surface of the fiber 3 rest.

The space between the plane-parallel plates 6 . 7 is here by a silver conductive adhesive 8th filled. Instead of the silver conductive adhesive 8th however, another adjustment layer may be used.

5b shows an alternative embodiment of a possible coupling, this embodiment being largely similar to that described above and in FIG 5a shown embodiment, so that to avoid repetition of the above description 5a and reference is made in the following for corresponding components, the same reference numerals, which are characterized only to avoid confusion by two apostrophes.

A special feature of this embodiment is that the fiber 3 '' has a square cross-section, whereby the effective contact area between the plane-parallel plates 6 '' . 7 '' and the lateral surface of the fiber 3 '' is increased, which contributes to a more effective coupling of the ultrasonic waves.

5c shows a further embodiment of the coupling of the electro-acoustic transducer 4 to the fiber 3 of the waveguide 2 ,

Here are the electro-acoustic transducer 4 an annular piezoceramic 9 on which the fiber 3 hollow cylindrical surrounds, wherein in the annular gap between the annular piezoceramic 9 and the fiber 3 again a silver conductive adhesive 10 located.

This in 5d illustrated embodiment of a possible coupling of the electro-acoustic transducer 4 to the fiber 3 is largely consistent with that described above and in 5c illustrated embodiment, so that in the following to avoid repetition of the above description 5c is referenced.

A special feature of this embodiment is that the annular piezoceramic into several segments 11 divided, which is distributed around the circumference around the fiber 3 are arranged around.

Further shows 5e another embodiment of a possible coupling to the fiber 3 for this purpose with a coating material 12 is coated from a piezoactive material.

Finally shows 6 the waveguide 2 the in 1 illustrated coupler arrangement 1 when working on a bone 13 where the bone 13 a cancellous bone shown in the upper part and a cortex shown in the lower part 14 having. From the representation of the spongiosa is further evident that this has a complicated heterogeneous ne internal structure and in addition to a solid phase 15 also a liquid phase 16 includes.

About the waveguide 2 In this case, ultrasonic waves of a first vibration mode with a first frequency and a first wavelength in the bone 13 coupled. The ultrasonic waves of the first frequency in the range of 200 kHz to 900 kHz, due to their relatively low frequency below the cutoff frequency of the measurement object, mainly propagate in the solid phase 15 and have due to the relatively large wavelength on a correspondingly large depth of penetration.

About the waveguide 2 In this case too, ultrasonic waves of a first or second oscillation mode having a second frequency and a second wavelength are introduced into the bone 13 coupled. By contrast, these ultrasonic waves of the second frequency lie in the frequency range from 0.9 MHz to 3 MHz above the cutoff frequency and propagate mainly in the liquid phase 16 out. However, due to the smaller wavelength, the ultrasonic waves of the second frequency have a larger spatial resolution and a smaller dead zone.

The one in the bone 13 backscattered or reflected ultrasonic waves are from the coupler assembly 1 detected and then evaluated, with a multi-frequency evaluation of both the ultrasonic waves of the first frequency and the ultrasonic waves of the second frequency the advantage of large penetration depth of propagating in the solid phase ultrasonic waves of the first frequency with the advantage of large spatial resolution in the liquid phase propagating ultrasonic waves of the second frequency combined.

In addition, the use of the coupler arrangement according to the invention makes it possible 1 during an examination or when working on the bone 13 a dynamic focusing, adding the individual fibers 3 of the waveguide 2 be driven independently of each other, as already described in detail above.

Claims (29)

Coupler arrangement ( 1 ) for coupling and / or decoupling ultrasonic waves, in particular in an ultrasound device, with at least one elongate waveguide ( 2 ) for guiding the ultrasonic waves and at least one laterally to the waveguide ( 2 ) coupled electro-acoustic transducer ( 4 ), which has a piezoceramic, for generating and / or detecting the ultrasonic waves, characterized in that the piezoelectric ceramic for generating ultrasonic waves with a first vibration mode with a first frequency can be excited to transverse-strain oscillations and for generating ultrasonic waves with the first or a second vibration mode with a second frequency to thickness-stretching vibrations can be excited. Coupler arrangement ( 1 ) according to claim 1, characterized in that along the waveguide ( 2 ) several electroacoustic transducers ( 4 ) each side of the waveguide ( 2 . 3 . 3 ' ) are coupled. Coupler arrangement ( 1 ) according to claim 2, characterized in that the adjacent transducers ( 4 ) each have the same polarization direction and in the longitudinal direction of the waveguide ( 3 ) are arranged equidistantly at a distance substantially equal to the wavelength of the ultrasonic waves in the waveguide ( 3 ) or an integer multiple thereof. Coupler arrangement ( 1 ) according to claim 3, characterized in that the transducers ( 4 ) in the waveguide ( 3 ) Generate ultrasonic waves of the first oscillation mode having a first wavelength and the first frequency and ultrasonic waves of the first or second oscillation mode having the second frequency and ultrasonic waves of the second oscillation mode having a second wavelength and a second frequency greater than the first frequency, wherein the number of transducers ( 4 ) is less than or equal to half the quotient of the second frequency and the first frequency. Coupler arrangement ( 1 ) according to claim 2, characterized in that the adjacent transducers ( 4 ' ) each have opposite polarization directions and in the longitudinal direction of the waveguide ( 3 ' ) are arranged equidistantly at a distance substantially equal to half the wavelength of the ultrasonic waves in the waveguide ( 3 ' ) or an integer multiple thereof. Coupler arrangement ( 1 ) according to claim 5, characterized in that the transducers ( 4 ' ) in the waveguide ( 3 ' ) Generate ultrasonic waves of the first oscillation mode having a first wavelength and the first frequency and ultrasonic waves of the first or second oscillation mode having a second wavelength and a second frequency greater than the first frequency, wherein the number of transducers ( 4 ' ) is less than or equal to the quotient of the second frequency and the first frequency. Coupler arrangement ( 1 ) according to one of claims 4 to 6, characterized in that the first frequency between 200 kHz and 1 MHz and the second frequency between 1 MHz and 3 MHz. Coupler arrangement ( 1 ) according to one of the preceding claims, characterized in that the waveguide ( 2 ) several fibers ( 3 . 3 ' ), wherein the transducers ( 4 . 4 ' ) each side of the individual fibers ( 3 . 3 ' ) or groups of fibers ( 3 . 3 ' ) are coupled. Coupler arrangement ( 1 ) according to claim 8, characterized in that the individual fibers ( 3 ) at the proximal end of the waveguide ( 2 ) with respect to the longitudinal direction of the waveguide ( 2 ) protrude in a star shape. Coupler arrangement ( 1 ) according to claim 8 or 9, characterized in that the individual fibers ( 3 ) of the waveguide ( 2 ) have at least partially different sound propagation velocities. Coupler arrangement ( 1 ) according to one of the preceding claims, characterized that the waveguide ( 2 ) a distal end ( 5 . 5 ' . 5 '' . 5 ''' ) for material processing, wherein the distal end ( 5 . 5 ' . 5 '' . 5 ''' ) with respect to the longitudinal direction of the waveguide ( 2 ) is rotationally symmetrical. Coupler arrangement ( 1 ) according to one of the preceding claims, characterized in that the distal end ( 5 . 5 ' . 5 '' . 5 ''' ) of the waveguide ( 2 ) is spherical, conical or concave. Coupler arrangement ( 1 ) according to one of the preceding claims, characterized in that between the transducer ( 4 . 4 ' ) and the waveguide ( 3 . 3 ' ) as coupling agent a silver conductive adhesive ( 10 ) or an adaptation layer is arranged. Coupler arrangement ( 1 ) according to one of the preceding claims, characterized in that the transducer ( 4 . 4 ' ) two parts ( 6 . 7 . 6 '' . 7 '' ) between which one or more fibers ( 3 . 3 '' ) of the waveguide ( 2 ) are arranged. Coupler arrangement ( 1 ) according to one of the preceding claims, characterized in that the transducer ( 4 . 4 ' ) the waveguide ( 3 . 3 ' ) surrounds annularly. Coupler arrangement ( 1 ) according to claim 15, characterized in that the transducer ( 4 . 4 ' ) several segments ( 11 ), which extends over the circumference of the waveguide ( 3 . 3 ' ) are arranged distributed. Coupler arrangement ( 1 ) according to one of the preceding claims, characterized in that the waveguide ( 2 . 3 . 3 ' ) consists of a rigid material. Coupler arrangement ( 1 ) according to claim 17, characterized in that the waveguide ( 2 . 3 . 3 ' ) consists at least partially of aluminum, aluminum oxide, titanium, stainless steel or other metals or oxides. Coupler arrangement ( 1 ) according to one of the preceding claims, characterized in that the waveguide ( 2 . 3 . 3 ' ) consists of a flexible material. Ultrasonic device, in particular medical diagnostic or therapeutic device or material processing or testing device with a coupler arrangement ( 1 ) according to any one of the preceding claims. Ultrasound method for the examination of a test object ( 13 ) with the following steps: coupling ultrasonic waves of a first oscillation mode with a first frequency and a first wavelength into the measurement object ( 13 ), wherein the first frequency is less than one through the measuring object ( 13 ) predetermined limit frequency is below which in the object of measurement ultrasonic waves substantially only in a solid phase of the test object ( 13 ), - Detection of the object to be measured ( 13 ) backscattered and / or reflected and / or delayed ultrasonic waves having the first frequency and / or the second frequency, - evaluation of the intensity and / or the transit time and / or the frequency spectrum and / or the delay time of the detected ultrasonic waves of the first frequency and / or the second frequency, - the ultrasonic waves having at least one laterally on a waveguide connected to the object ( 2 ) coupled electro-acoustic transducer ( 4 ), which has a piezoceramic, are generated and / or detected, characterized in that the piezoelectric ceramic for generating ultrasonic waves with a first vibration mode at the first frequency is excited to transverse-strain oscillations and for generating ultrasonic waves with the first or a second vibration mode is excited to the second frequency to thickness-strain oscillations. Ultrasonic method according to claim 21, characterized that the first frequency between 200 kHz and 0.9 MHz and the second Frequency is between 0.9 MHz and 3 MHz. Ultrasonic method according to Claim 21 or 22, characterized in that the ultrasonic waves propagating in solid phase of the first frequency and the ultrasonic waves of the second frequency propagating in the liquid phase are each separated from one another by ultrasound radiation having different center frequencies in the test object ( 13 ) are coupled. Ultrasonic method according to one of claims 21 to 23, characterized in that a plurality of ultrasonic waves spatially distributed in the measurement object ( 13 ), wherein the delay time and / or the phase position of the individual ultrasonic waves is adjusted separately from one another in order to determine the spatial position of the focus of the ultrasonic waves in the measurement object ( 13 ). Ultrasonic method according to claim 24, characterized in that the spatial position of the focus of the ultrasonic waves in the measurement object ( 13 ) is determined as a function of the evaluation of the intensity and / or the transit time and / or the frequency spectrum of the detected ultrasonic waves. Ultrasonic method according to claim 25, characterized in that by the evaluation the intensity and / or the transit time and / or the frequency spectrum of the detected ultrasonic waves, the spatial position of an interface in the measurement object ( 13 ), wherein the focus of the ultrasonic waves in the measurement object ( 13 ) is adjusted to the interface. Ultrasonic method according to one of claims 21 to 26, characterized in that the individual ultrasonic waves in each case via a fiber of a multi-fiber waveguide in the measurement object ( 13 ) coupled and / or from the measurement object ( 13 ) are detected, wherein the individual fibers of the waveguide are each separately connected to at least one electroacoustic transducer. Ultrasonic method according to claim 27, characterized by the following steps: determination of the propagation times of the ultrasonic waves between the coupling into the measuring object ( 13 ) and the subsequent detection, whereby the propagation time for the individual fibers of the waveguide is determined separately, - determination of the distribution function of the transit times for the individual fibers of the waveguide, - adjustment of the focus of the coupled ultrasonic waves as a function of the determined distribution function. Ultrasonic method according to one of claims 21 to 28, characterized in that the measuring object ( 13 ) is a bone with a cortex and cancellous bone.