JPH0866395A - Converter array for ultrasonic wave diagnosis,of which focuspoint in height direction is adjustable - Google Patents

Abstract

PURPOSE: To make electric focusing in a plurality of directions possible by dividing an element of array into a plurality of sub-elements in height direction and setting an aspect ratio that varies corresponding to the distance from the central vertical axis of the array to each sub-element. CONSTITUTION: Array 16 comprises a plurality of elements e1 , e2 , and so on. Each element (for example element e1 ) is divided into a plurality of sub-elements (e1 A to e1 D) in height direction. The central sub-element has a size represented by 5-2 that means a width of 5 units in height direction and 2 units in vertical direction, and the sizes of the sub-elements on both sides thereof decrease gradually as being 4-2, 3-2, 2-2, and 1-2 sequentially. All the sub-elements have the same thickness T. Further, a plurality of active electrodes 21, 23, 26, 24 and 22 are all connected to each other by wire 28 soldered to each sub-element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transducer array used for ultrasonic diagnostic image processing, and more particularly to an ultrasonic transducer array capable of focusing in the height direction.

[0002]

Image information is obtained by focusing a group of individual elements by electrically actuating them to manipulate a beam of ultrasonic energy. Transducer arrays are known. The elements of the array may comprise a number of concentrically arranged rings forming an annular array.
The present invention relates to a linear array in which elements conventionally used for linear array or phased array image processing are arranged linearly. The linear array may also have a bend in the image processing plane that the beam diverges to form a fan-shaped image processing plane. These linear arrays are ideal for scanning and imaging in the two-dimensional area in front of the array.

Longitudinal direction of array elements (longitudinal direction)
The array of (1) makes it possible to electrically narrow down to a narrow beam in the image processing plane of the array beam. One row of elements of the array does not allow electrical focusing in the horizontal axis of the plane, the thickness direction, which is usually desirable for obtaining high resolution thin image "slices". Is. The prior art for narrowing the beam to a flat image plane is to machine the beam in this lateral, or height direction, by either advancing the elements along the contours of the area or by lensing each element. Focus on the subject. More recently, it has been shown that focusing in the height direction can be performed by controlling the piezoelectric properties of the element in this direction. In this technique, known as shaded polarization, elements are strongly shaded so that they are most strongly polarized in the center and become less polarized towards each end of the element in the height direction. An electric field is applied uniformly to each element to taper the polarization of the piezoelectric element. This technique makes the acoustic transmittance of each element greater along the longitudinal centerline of the array and lesser along each height direction. One of the characteristic drawbacks of this technique is the polarization shadow.
It is difficult to accurately control the magnitude and gradient of the motion shading.

It is also known to apply the same principles used to focus a beam longitudinally to perform electrical height focusing. Second, third and further rows of elements are arranged side by side and parallel to the first row of longitudinal elements. This forms the individual rows of elements in the height direction, and the timed actuation and sampling of these elements enables the electrical focusing of the beam in the height direction. However, this electrical problem solution greatly increases the complexity of the ultrasound system. The number of elements in the array will be triple or more. That is, the 128 element array is a two-dimensional array of 384 or more elements. This 2
The number of transmitters and receivers required to operate the dimensional array is correspondingly increased, which greatly increases the cost of the device. Accordingly, there is a need for a transducer array that exhibits improved performance over conventional mechanical height focusing techniques while avoiding significant cost increases and the complexity of electrical height focusing.

[0005]

SUMMARY OF THE INVENTION The present invention provides a transducer array capable of focusing an ultrasonic beam in the height direction. In the first embodiment, this array of transducers is
It consists of a composite structure of elements of piezoelectric material and a binding matrix of non-piezoelectric material. The electromechanical coupling coefficient of an element of piezoelectric material is such that the element along the longitudinal centerline of the array exhibits greater electromechanical coupling than the element towards the longitudinal end of the array.
It is controlled by controlling each of these individual aspect ratios. This allows control of the aspect ratio of the piezoelectric element in the composite structure to allow focusing of the acoustic beam in the height direction. In a second embodiment, the acoustically effective aperture of the transducer array is expanded longitudinally as the array is focused deeper. The effective aperture expands in the height direction as it expands in the vertical direction as the number of operating elements increases. In the preferred embodiment, this expansion causes the acoustically effective aperture to be wider at the longitudinal ends of the array than at the central portion, with the most longitudinally spaced elements being laterally separated but electrically isolated. A sub-element connected to is formed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an ultrasonic diagnostic transducer array according to the present invention will be described. First, FIG. 1 shows a conventional linear array 10 of piezoelectric transducer elements. The array 10 comprises a number of individual transducer elements labeled e ₁ , e ₂ , e _3, etc. in the figure. The figure also shows the arrangement of the array in two directions, the longitudinal direction represented by arrow L and the elevational direction represented by arrow E. The plane on which the array operates is
Parallel to the longitudinal arrow L, it extends outward from the center of the array surface. As is well known, the transmitted beam impinging in the plane of motion can be longitudinally focused by activating the elements as a group of elements at approximately the same time but at slightly different times. At this time, the tuned ultrasonic transmission can focus or direct the transmission beam to a desired point.

However, such focusing or guidance of ultrasonic waves is impossible in the height direction because there is only one element in the height direction. Electrical guidance and focusing in the height direction requires additional rows of elements, which form a two-dimensional array and add considerable complexity to the transmitting and receiving electronics. In a single row, the only practical height-focusing possible is a machine such as a curvilinear arrangement of the height-wise array or lens-shaping, as described in US Pat. No. 3,936,791. Or by the above-mentioned shadow polarization technique.

FIG. 2 shows a plan view of the emitting surface of a transducer array 12 similar to the array of FIG. 1 except that each element is subdivided. 2A is a side view of the array of FIG.
It also shows a reference electrode 14 on the emitting surface of the element, and actuating electrodes 15, 17, 19 on the opposing surfaces of each pair of subdivided elements.
In the array 12, elements corresponding to e ₁ , e ₂ and others in FIG. 1 are e _1A and e _1B ; e _2A and e _2B ;
Like so on, it is subdivided into two sub-elements. From the comparison of FIG. 2 with FIG. 1, the area of the transmitting surface of each subdivided element is half of the original total element, which changes the aspect ratio of each divided element. The aspect ratio change that affects the performance of each element is shown in FIG.
In the figure, it is the ratio to the thickness of the element between the electrodes indicated by the arrow represented by T. It is this ratio that determines the electromechanical coupling coefficient of the element, which represents the amount of acoustic energy produced from a given amount of actuation energy. In the array 12, it is preferable to perform a mechanical operation in the direction of the thickness dimension T in order to emit an acoustic wave outward from the emitting surface of the element. As this aspect ratio changes, the conversion rate of electrical energy into mechanical acoustic energy improves, as measured by the increase in the electromechanical coupling coefficient of the element. Since the other factors are equal, the subdivided elements e _1A and e _1B are
It is expected to convert electrical energy into acoustic energy more efficiently than the corresponding element e _{1 of} . The array 12 is operated by simultaneously actuating the subdivided pairs, which energize the electrodes 15,1.
This is the reason why 7 and 19 are bridged to the subdivided element pairs.

In accordance with the present invention, the electromechanical coupling coefficient of the elements of the transducer array of composite material varies in the height direction so as to form a height-focusable waveform of the emitted energy. A composite transducer is one in which a piezoelectric material is dispersed in a non-piezoelectric matrix. A converter array 16 which is an embodiment to which these principles are applied is shown in FIGS. In the plan view of the emitting surface of the array 16 of FIG. 3, the array 16 is comprised of a number of elements e ₁ , e _2, etc. Each element is 4
It is subdivided in the height direction into one sub-element. The element e ₁ is composed of four sub-elements e _1A , e _1B , e
It is subdivided into _1C and e _1D . As with array 12, this subdivision improves the electromechanical coupling coefficient of element e ₁ compared to the operation of a single, monolithic element. The manner in which the aspect ratio of the transducer element changes to achieve the desired change in electromechanical coupling coefficient is material dependent. This is because when a certain aspect ratio change of an element made of one substance has the same aspect ratio change in an element made of another substance, it affects the coupling coefficient differently from those of other substances. Means that there is.

The element is subdivided in the longitudinal direction and twice in the height direction so that the width of the surface area of the element is reduced two-dimensionally so that the width of the surface area of the element decreases in relation to the distance from the center of the element in that direction. It is beneficial to subdivide the elements in the direction and then in the height direction. 3 and 4, the central sub-element has a size labeled 5-2. In this embodiment, the central sub-element has a width of 5 units in the height direction and 2 units in the longitudinal direction. The sub-elements on either side of the central sub-element have a size designated 4-2, which in this embodiment is given a width of 4 units in the height direction and 2 units in the vertical direction. There is. Sub-elements extending outward from the center are 3-2, 2-2, and 1-2.
The size gradually decreases. It is shown that the aspect ratio of the sub-elements varies from the central sub-element 5-2 to the end sub-elements 1-2. This change is vertically symmetrical with respect to the central sub-element.

As FIG. 4 shows, all these sub-elements have the same thickness T. Thus, this aspect ratio changes outward from the central sub-element. This varying aspect ratio causes a decreasing slope of the electromechanical coupling coefficient from the central subelement to the end subelements in the height direction. FIG. 4 also shows that the actuated electrodes 21, 23, 26, 24, and 22 are all connected together by a wire 28 soldered to each sub-element. The electrical pulse supplied to the wire 28 is the central sub-element (5-2).
To emit more intense acoustic energy than any of the other sub-elements, and the magnitude of the acoustic energy emitted from the sub-elements decreases as one goes to the edge (1-1). In this way, all the sub-elements operate and simultaneously transmit acoustic energy, but the waveform of the transmitted energy is the center of the element in the height direction as indicated by the large arrow C compared to the small arrow S at the end of the element. It is possible to concentrate the transmitted energy in the height direction. This concentration is achieved by the above selection of the aspect ratio of the sub-elements.

Each working electrode 21-26 reaches all four subdivided elements e _1A -e _1D in the longitudinal direction.
All subelements of element e ₁ therefore operate simultaneously. The subdivision in the height direction results in an efficient conversion of electrical operating energy into acoustic energy, and the aspect ratio of the sub-elements, which changes from the center to the outside, focuses the energy in the height direction. To do. In constructional examples, the voids 20 between the sub-elements may be filled with air or may be filled with a non-piezoelectric adhesive composition such as epoxy to retain the sub-elements in a matrix. . FIG. 4 also shows the array supported by a backing of filler material 18 as a damping material.

FIG. 5 shows a second aspect of the present invention with some additional concepts added to achieve height focusing.
An example of is shown. FIG. 5 shows an array 30 made up of sub-arrays 32-40. The central sub-array 32 has paired sub-arrays 34a and 34b, and 36a and 36b flanked on both sides in the vertical direction. As in the embodiment of FIGS. 3 and 4, the central sub-array 32 has a larger aspect ratio than any of the side-disposed sub-arrays and has side-disposed sub-arrays that extend further in the height direction. In addition, the pairs of sub-arrays arranged on this side are separated from each other. Sub arrays 34a and 34b
Further, two pairs of sub-arrays 38a and 38b and 40a and 40b are laterally arranged on the side surfaces of and 36a and 36b. The sub-arrays of each of these pairs are vertically separated by a greater distance than the inner pairs 34a and 34b and 36a and 36b.

The array 30 is operated by operating a combination of different subarrays, depending on the depth of the observation area in which the acoustic beam is concentrated. The effective aperture of the array increases as the acoustic wave is transmitted deeper. In the near field, the subarray 32 is operated alone without the use of any other subarray. In the region of the intermediate depth, with the central array, 34
a and 34b and 36a and 36b are used. The addition of sub-arrays located on these sides widens the effective effective aperture of the array and, when used in conjunction with the central array, directs the transmitted beam longitudinally through the timed movement of the individual elements in the sub-array to provide a focal point. Be matched. Focusing in the height direction is achieved in two ways. The first method is that the larger aspect ratio and electromechanical coupling coefficient of the elements of the central subarray 32 cause the central subarray to emit more acoustic energy at the same level of operating energy than the laterally arranged subarrays. . The second method splits the corresponding sub-array in the laterally-placed pair, in combination with an appropriate operating time delay, so that the acoustic beam is concentrated in the height direction towards the longitudinal center of the array. The acoustic energy component to be given is given.

All sub-arrays are active when transmission to distant areas is required. As a result, the effective diameter of the array 30 is maximized in the vertical direction. The outermost sub-arrays 38a and 38b and 40a and 40b are of greater height due to the effect of their position being similar to the laterally arranged sub-arrays 34a and 34b and 36a and 36b, but further out of them in the height direction. Gives a focusing effect in the vertical direction. Thus, a beam that is focused both vertically and vertically is
It is possible to transmit to the maximum operation depth in the area of the array 30.

In the structure of the array 30, the working electrodes of the vertically opposed elements of the paired subarrays are electrically connected to each other. While the elements of the array are manipulated separately in the longitudinal direction with phase operating time, the corresponding elements of the paired sub-arrays can be coordinated to achieve the desired focusing effect in the height direction. it can.

A modified embodiment of the array 30 of FIG. 5 is shown in FIG.
And 7 are shown. In FIG. 6, the contour line 42
Represents a rod-shaped piezoelectric substance that is cut in a diced shape as shown by the straight lines in the contour line, but only the shaded sub-elements are connected to the working electrode and can be operated. ing. The central sub-array e _C extends from element e ₇ to element e ₁₆ . The central sub-array e _C operates when the array emits acoustic energy into the near field. As the depth of the area increases,
Subelements arranged laterally in the longitudinal direction starting from _subelements e _6A and e _6B and e _17A and e _17B are added.
As the depth of the area increases, other sub-elements are added to expand the effective aperture until the full effective use of e _1A and e _1B to e _22A and e _22B at maximum depth is used. Similar to the previous embodiment, the elements of the central sub-array have a larger aspect ratio than the paired sub-elements to provide greater strength to the center of the array. The angular tilt of the split sub-elements towards the outside of the pair gradually increases the focusing effect in the height direction of the sub-element pairs as the effective depth increases with increasing area depth. Let

These effects are illustrated in the remote area of the perspective view of the array 42 and its emitting surface of FIG. The transmitted wavefront 60 is orthogonal to the transmitter surface of the array and extends from its central longitudinal axis. The centerline CL of the plane 60 extends from the center of the center subarray e _C. In the figure, array 42 is focused on point F and all elements of the array are in motion. To focus the transmit beam longitudinally, the actuation sequence proceeds inward until the outermost element is activated first and the central element of the array is activated last. Height focusing, which focuses the transmitted beam on the plane 60, is achieved by the division of the upwardly extending sub-elements 52 and, conversely, the downwardly extending sub-elements 54 and the corresponding sub-elements 56 and 58. It The dotted lines from the corners of the array show the effect of this height focusing.

FIG. 8 shows the waveform of a representative acoustic beam in the embodiment of FIGS. 5-7. In this figure, the transducer array is shown end up, with the transmit beam extending to the right. In the near field, the central element e _C is used alone so that the beam P ₁ is focused at the focus F ₁ of the near field. The element e _{C in} this figure corresponds to the central sub-array 32 of FIG. 5 or the central element e _C of FIG. In the remote region, the central element e _C is used with a pair of outwardly extending elements e _nA and e _nB to form a focused beam P ₂ at point F ₂ . The array has good elevation focus characteristics in both near and remote areas.

In the embodiment of FIGS. 6 and 7, as in FIG. 5, vertically aligned elements (height aligned elements) are electrically connected together and operate simultaneously. However, if desired, the working electrodes of the vertically aligned elements may be electrically separated, in which case the elements operate independently of each other. This offers the opportunity to gain additional operational benefits from the array. For example, referring to FIG. 7, it is possible to activate the corresponding upwardly extending sub-elements 52, 56 at a slightly different time than the downwardly extending sub-elements 54, 58. This causes acoustic energy from each extension of the sub-elements to reach the focal point and reflect from the in-focus target in a slightly different time and phase relationship. Such time adjustment and phase change are
Speckle pattern (speckl) typical of ultrasonic images
e) causing the spatial mixing of acoustic beams that disturb the normally occurring interference of sound waves that cause the formation of an e pattern). Such a method of array operation enables the formation of ultrasound images with less speckle content compared to the simultaneous operation of opposing sub-elements.

A second method for reducing mottle content is illustrated in FIG. 5A, which is an end view of the array of FIG. In FIG. 5A, the sub-arrays 32,3
4 and 36, and 38 and 40 have different thicknesses to provide different subarrays of frequency response. The middle subarray has the highest frequency response, the subarrays on either side of it have the lower frequency response, and the outermost subarrays have the lowest frequency response.
As the depth increases and the outer subarray is added to the effective aperture, the lower frequency subarray operates to transmit and receive ultrasonic signals. When the electrical signals formed from all the operating sub-arrays are focused to form a beam, the frequencies of the different received signals are mixed,
Reduce the mottle content in the generated beam.

In summary of the invention thus far described, the present invention provides an ultrasonic diagnostic transducer array capable of electrical focusing in the longitudinal plane as well as height focusing.
The elements of the array are divided in the height direction, giving the sub-elements an aspect ratio that varies in proportion to their distance to the central longitudinal axis of the array. Such a change gives the sub-elements an electromechanical coupling coefficient that changes so that the intensity of the transmitted energy is concentrated on the central vertical axis. In a second embodiment, the elements have height extensions that vary in proportion to their position change from the longitudinal center of the array. The elongate element is acoustically divided into height sub-elements to allow heightwise focusing or spatial organization of the transmitted acoustic energy.

[0023]

The present invention provides an ultrasonic diagnostic transducer array capable of electrical focusing in the longitudinal plane and focusing in the height direction. The elements of the array of the present invention have height-divided sub-elements having an aspect ratio that varies with distance from the central longitudinal axis of the array. Such a change in aspect ratio changes the electromechanical coupling coefficient of the sub-elements so as to concentrate the intensity of transmitted energy on the central vertical axis. In a second embodiment, the elements have height extensions that vary in proportion to their position change from the longitudinal center of the array. The extended element is
It is acoustically divided into height-wise sub-elements, allowing heightwise focusing or spatial concentration of the transmitted acoustic energy.

[Brief description of drawings]

FIG. 1 is a plan view of a linear array of conventional piezoelectric transducer elements.

FIG. 2 shows that each element is subdivided (subdice).
FIG. 6 is a plan view of a linear array of piezoelectric transducer elements being d). 2A is an enlarged end view of the subdivided array of FIG.

FIG. 3 is a plan view of a height-focusable transducer array of the present invention.

FIG. 4 is a side view of the transducer array of FIG.

FIG. 5 is a plan view of a second embodiment of a transducer array focussed in the height direction according to the present invention. And FIG. 5A is an end view of one method for manufacturing the array of FIG. 5 with varying thickness.

FIG. 6 is a plan view of a modified transducer arrangement shape of the array of FIG.

7 is a perspective view for explaining the focusing effect of the transducer array of FIG.

FIG. 8 shows the shape of the transmitted acoustic beam in the height direction of the transducer array of FIGS.

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Claims (22)

[Claims] 1. An array of ultrasonic transducer elements for emitting an acoustic beam in a plane including a central longitudinal axis thereof, wherein the subelements are arranged in the height direction and have an electromechanical coupling coefficient of the central longitudinal axis. Comprising a plurality of elements arranged in a longitudinal direction, the sub-elements having sub-elements with varying aspect ratios, which vary according to the distance from the axis,
A transducer array for ultrasonic diagnosis capable of focusing in the height direction, which is composed of ultrasonic transducer elements that form an acoustic beam whose intensity changes in the height direction. 2. The aspect ratio of the subelements is varied such that the subelements closer to the central longitudinal axis have a greater electromechanical coupling coefficient than subelements further away from the central longitudinal axis. An array of ultrasonic transducer elements as described in 1. 3. All the sub-elements arranged in a certain row in the height direction have a common thickness and a common width in the vertical direction.
An array of ultrasonic transducer elements according to claim 2 and exhibiting different lengths in the height direction. 4. The array of ultrasonic transducer elements of claim 3, wherein each element of the array comprises a plurality of said rows of sub-elements arranged in a height direction. 5. The ultrasonic transducer according to claim 1, wherein the sub-element is an array made of a piezoelectric ceramic material, and a composite array in which a gap between the sub-elements is filled with a non-piezoelectric material. Array consisting of vessel elements. 6. The array of ultrasonic transducer elements according to claim 5, wherein the non-piezoelectric material is an epoxy material. 7. The electromechanical coupling coefficient of one row of sub-elements aligned in the height direction is larger and located closer to the central longitudinal axis than sub-elements farther from the central longitudinal axis. Together with the sub-elements having a coupling coefficient, it varies as a function of the distance from the central longitudinal axis, which results in an acoustic beam having a greater intensity at the height center of the array than at the height edges. An array of ultrasonic transducer elements according to claim 1, formed by: 8. All sub-elements of the elements of the array have first and second electrodes located on opposite surfaces of the sub-elements, the first electrodes electrically connected to each other. And an array of ultrasonic transducer elements according to claim 1, wherein the second electrodes are electrically connected to each other. 9. The first electrode is located on the emitting surface of the sub-element and is connected to a reference potential, and the second electrode is located on the opposite surface of the sub-element, 9. An array of ultrasonic transducer elements according to claim 8 connected to a switch actuated potential. 10. An array of longitudinally arranged ultrasonic transducer elements for emitting acoustic beams in a plane extending from a central longitudinal axis of the array, the first group of elements being the array. Centrally in the longitudinal direction of the element, capable of actuation of acoustic energy transmission to near and distant regions, the second and third element groups being located on the side of the element in the longitudinal direction opposite the first group. And the second
And the elements of the third group spread more in the height direction from the central longitudinal axis than the first group of elements, wherein the second and third groups of elements are the first group of elements. A transducer array for ultrasonic diagnostics capable of focusing in the height direction, which is operable in cooperation with the ultrasonic transducer element and is capable of focusing in the height direction in a remote area. 11. A first and a second group of sub-elements, each of which comprises a second and a third group of elements which are vertically opposed to each other.
And an array of ultrasonic transducer elements according to claim 10, comprising a second group and acoustically isolated from each other. 12. The first and second sub-elements
Opposite sub-elements of a group of
An array of ultrasonic transducer elements according to claim 11. 13. The ultrasonic transducer element according to claim 12, wherein said elements and sub-elements are operable longitudinally independent of each other in the longitudinal direction of said plane to steer and focus said beam. Array. 14. The ultrasonic transducer element of claim 11, wherein the elements of the first group have a greater length in the height direction than the subelements of the first and second groups of subelements. Become an array. 15. A second of said array wherein said first group of sub-elements of each of said second and third groups of elements is stepped in one corner of said central longitudinal axis in the height direction. The second group of sub-elements of each of the second and third groups of elements is located relative to the central longitudinal axis in a height direction from that of the second longitudinal axis. An array of ultrasonic transducer elements as claimed in claim 11 located on a third longitudinal axis of the array which is stepped on the side to be processed. 16. The array of ultrasonic transducer elements of claim 15, wherein the second and third longitudinal axes are stepped symmetrically with respect to the central longitudinal axis. 17. Further comprising fourth and fifth groups of elements located on opposite sides of said second and third groups of elements, each of said fourth and fifth groups having a height of A first and a second group of sub-elements facing each other in a direction, wherein the first group of sub-elements of each of the fourth and fifth groups of elements is from the second longitudinal axis. Also located to a greater extent in the fourth longitudinal axis of the array stepped to one side of the central longitudinal axis in the height direction, and of the fourth and fifth groups of elements. The second of each sub-element
Of the fourth group to a degree greater than the third vertical axis.
16. The ultrasonic transducer element of claim 15 located on a fifth longitudinal axis of the array which is stepped in a height direction from that of a longitudinal axis of the central longitudinal axis. Array. 18. A sub-element of each of said groups of sub-elements is longitudinally angled outwardly from a longitudinal side of said first group of elements, and outwardly from said first group of elements. 12. An array of ultrasonic transducer elements according to claim 11 located along respective lines in the plane of the array that are angled to extend greater distances from the central longitudinal axis as they extend. . 19. The elements and sub-elements are longitudinally and vertically oriented to steer and focus the beam in the longitudinal direction of the plane and spatially mix transmitted acoustic energy. An array of ultrasonic transducer elements according to claim 11, which are operable independently of each other. 20. The first group of elements has a higher frequency response than the second and third groups of elements, whereby signals of different frequency content are produced by different groups of elements in a remote area. An array of ultrasonic transducer elements according to claim 10 received. 21. The array of ultrasonic transducer elements of claim 20, wherein the first group of elements has a smaller thickness in the transmit direction than the second and third groups of elements. 22. An array of ultrasonic transducer elements arranged in a longitudinal direction of the array that emits an acoustic beam in a plane extending from a central longitudinal axis of the array, wherein the elements are from a longitudinal center of the array. A transducer array for ultrasonic diagnostics which can be focused in the height direction and is composed of a number of ultrasonic transducer elements having an extension in the height direction which changes in response to the change of the position.