DE3404852A1 - Phase-controlled ultrasound receiver - Google Patents

Abstract

The invention relates to a phase-controlled receiver intended for an ultrasound diagnostic apparatus or the like for the expedient change of the phases of the output voltages of transducer elements (A1-A4) picking up ultrasonic waves and for summation of these voltages for the purpose of changing the directional properties or other characteristics of the ultrasonic radiation. The receiver comprises a number of blocks which each consist of a tapped delay line (10-12) and a coupler point switch (30-32). The delay line and the coupler point switch are capable of choosing a desired delay period or delay time span from different ones of the delay lines (10-12). As such, the receiver is suitable for all types of scanning, from linear scanning to sector scanning. <IMAGE>

Description

Henkel, Pfenning, Feiler, Hänzel & Meinig

Yokogawa Medical Systems, Limited Tokyo, Japan

Patent attorneys

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FA 84024

February 10, 1984 / wa

Phase controlled ultrasonic receiver

The invention relates to a phase-controlled receiver for use in an ultrasonic diagnostic device or the like. for the appropriate change of the phases of the voltages of transducer elements, the ultrasonic waves receive or decrease, and for summing these voltages to change the directional properties the ultrasonic rays or other characteristics.

Electronically scanning ultrasonic diagnostic devices can be divided into two categories depending on their working principle divide, namely into a linear scan (linear scan) and a sector scan type (sector scan). In linear scanning, the transducer element row essentially sends or receives ultrasonic beams perpendicular to this row. The transducer elements are sequentially energized as if an ultrasonic beam would be implemented for scanning purposes.

With this type of scanning, the scanning lines generated in parallel therefore deliver a tomogram of an examination subject.

In sector scanning, almost all transducer elements of a row or arrangement (array) are in different Clock or time relationships excited to the directions of propagation of the sent or received ultrasonic beams to perform a scan in the form of a geometric sector steer.

In accordance with these different working principles of the two types, ultrasonic diagnostic devices of the linear scanning type commonly used for diagnostic purposes on the human abdomen. Those of the Sector scan-type, on the other hand, are used to look inside a human body

through the space between adjacent ribs, especially for heart diagnosis or similar purposes, to win.

As a result, the linear and sector scan type ultrasonic diagnostic devices have become quite different in the past Devices built.

Recently, however, a device has been developed

the functionally either represents a middle thing between the devices of the two types of scanning described or does not belong to any of these types. In addition, ultrasound diagnostic equipment is required to as the only device capable of working in both the linear and sector scanning modes.

A device that meets the requirements outlined above

2Q is sufficient, is shown in Fig. 1 in block diagram form. This device has a delay line 1, the structure of which is shown in Fig. 3, wherein One LC circuit unit each from (the elements) L and C is arranged between adjacent taps a, - a is to delay the electrical input signal by equal increments. According to the definition as described herein, a delay line is one with a number of taps, as shown in FIG. The arrangement continues

OQ a crosspoint switch 3, with the switch (er) elements are arranged at the points where the longitudinal lines (output lines) and the cross lines (Input lines) meet or cross each other. These switching elements are under the control of a

gc control unit 4 open and closed. Oscillators, each of which converts its electrical input signal into an acoustic signal, form a row (array)

A. Each transducer element is, for example, from i

Lead zirconate titanate (PZT). The clarity only four transducer elements are shown in the arrangement of FIG. 1, but is in fact a larger number of transducer elements, e.g. 32 elements, are present. The arrangement further includes a terminal B and a set of amplifiers U.. The outputs of the latter are to the cross lines of the crosspoint switch 3 connected. The signal provided by delay line 1 becomes amplified by an amplifier G.

Although the circuit of FIG. 1 is in an embodiment for processing the series of transducer elements A. Delivered signals is shown, it can if the amplifiers Ul and G bidirectional devices are, also as a circuit for emitting or transmitting ultrasonic beams from the transducer elements A. serve. The circuits described therefore fulfill both transmission and reception functions; for the sake of simplicity, however, they are generally treated as receiving circuits in the following.

If the delay line 1 in the arrangement according to FIG. 1 has a sufficiently large resolution of the delay time and a sufficiently large number of taps of delay time or line to adapt to both linear and sector scanning to be adapted, and if the number of switching elements of the switch 3 is large enough, the receiver can According to Fig. 1, not only linear and sector scanning, but also one between these two types of scanning Carry out horizontal scanning. The receiver can therefore easily be described as a multi-purpose device, because all (according to Fig. 4 four) transducer elements that are required to deliver a visible image, be connected to the crosspoint switch 3

can and the delay line 1 a sufficiently large resolution of the delay time and a sufficient has a large number of taps to perform all types of scanning from linear to sector scanning to be able to, wherein the control unit 4 to close any intersection or coupling point in the switch and able to open.

Fig. 1 illustrates a configuration in which the Arrangement of the transducer elements A. is connected for sector scanning; hence the following is the operation briefly described in the sector scan mode. In Fig. 6 the type of propagation is the reflected Ultrasonic waves or echoes shown. For example, an echo runs from point P1 according to FIG. 6 return to row A. in the form of a wave front. The times at which the echoes reach the transducer elements, are therefore different depending on the angles of incidence of the echo on the transducer elements. To do it to be able to accurately record the echo from e.g. the point P1, the transducer elements depend on electrical signals generated by the arrival of the acoustic echo with a corresponding time delay subject so that these signals are in phase. Since the arrangement of FIG. 1 with the ideal delay line 1 and the crosspoint switch 3 is provided, the aforementioned phase adjustment can be used with it can be done properly.

If a linear scan is to be carried out with the arrangement of FIG. 1, the probe (probe) for Sector scanning by a shown in Fig. 2, consisting of a number of transducer elements A. Replaced the probe connected via connection B. Linear scanning probes generally consist of a larger number of transducer elements than sector

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scanning probes, but that's the number for one single ultrasonic beam excited transducer element equal to or smaller than the number of these elements for sector scanning. In the case of FIG. 2, four transducer elements become independent of the respective type of scanning excited. The energized transducer elements are by means of the selector circuit 6 of the probe according to FIG. 2 for each ultrasonic scanning beam is sequentially or consecutively selected. It follows that the The receiver according to FIG. 1 receives essentially the same number of input signals via the connection B, regardless of whether the scanning is in the linear or the sector scanning mode; the recipient is therefore usable for both scanning modes.

With the linear scanning described, an echo hits at smaller angles than with the sector scanning on the row of transducer elements A. It can therefore be seen that the delay line 1 and the Crosspoint switch 3 can be used appropriately for linear scanning. As described above, can the arrangement of Fig. 1 to correspond to all cases from linear to sector scanning, but occur the difficulties indicated below.

1) When sector scanning is performed with the arrangement of Fig. 1, delay lines 1 and crosspoint switch 3 effectively used. With linear scanning, on the other hand, only a fairly small one becomes Part of the line 1 and the switch 3 used. It can thus be said that the arrangement of FIG represents a redundancy configuration.

2) Since the delay line 1 has only a single output, it is impossible to have multiple azimuths or to achieve electrical echo signals emanating from several acoustic points at the same time.

3) As can be seen from the structure of the delay line according to FIG. 3, at any point in time only one switching element of the crosspoint switch 3 can be closed for each cross line. The delay line 1 therefore works with a low time-wise efficiency.

With regard to the circumstances outlined above Thus, the invention is based on the object of providing a phase-controlled ultrasonic receiver create, which adapts itself to different types of scanning, such as linear and sector scanning or an intermediate Abtastart, able to adapt and the one or more effective and economically working (used) delay line (en).

The solution to this problem results from the features characterized in claim 1.

The phased array receiver provided for an ultrasonic diagnostic device according to the invention comprises active transducer elements, crosspoint switches and several comparatively small blocks. The latter have in common associated input lines, so that those generated by the transducer elements upon receipt of the ultrasonic waves Signals can be applied to the blocks via the common input lines. The ones going through the blocks Signals are delayed and in any combination due to the action of the crosspoint switch summed up. The blocks can be connected in series to create longer delay periods or time spans for sector scanning. In addition, the blocks can be connected in parallel to their output signals to be used separately and thus to allow linear scanning with high resolution.

The following are preferred embodiments of the invention explained in more detail with reference to the drawing. Show it

Fig. 1 is a block diagram of a previous one, for both linear and sector scanning used (ultrasonic) receiver,

Fig. 2 is a schematic representation of the structure a probe for linear scanning,

3 is a circuit diagram of a delay line;

4 and 8 are block diagrams of phased receivers according to the invention, along with around

giving sections,

Fig. 5 is a graphical representation of the

Interaction between crosspoint switch and delay line introduced Zeitver

delays,

6 shows a schematic representation of a sector scan;

7 shows a schematic representation of a dynamic Focusing process,

9 and 10 are schematic representations of intermediate scans.

11 and 12 are schematic representations of further types of scanning and

oc Fig. 13 is a circuit diagram of another connection input

direction for delay accumulation. FIGS. 1 to 3 have already been explained at the beginning.

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Fig. 4 illustrates a phased one according to the invention Receiver and its surrounding or peripheral sections. The receiver includes delay lines 10, 11 and 12, which - with the exception of the number of taps - in the structure essentially correspond to the delay line described with reference to FIG. More precisely: the delay line 1 according to FIG. 1 requires a fairly large number of taps, while the individual delay lines 10, 11 and 12 according to FIG. 4 each have taps, the number of which is that of the delay line 1 according to FIG. 1, divided by a small whole Number, corresponds and is therefore smaller than in the previous arrangement. It should be noted that the Delay lines 10-12 need not necessarily have the same number of taps and the same delay time per tap. Also includes the receiver crosspoint switches 30, 31, 32 connected to the delay lines 10, 11 and 12, respectively and which work similarly to the crosspoint switch according to FIG. 1. The matrix-like at the points where the cross and longitudinal lines of the relevant switch meet, arranged switch (er) elements are closed by a control unit, not shown in FIG. 4 for reasons of clarity or open.

According to a feature of the invention, the receiver comprises a plurality of blocks each comprising a delay line and a crosspoint switch of the type described. This embodiment offers different, more detailed advantages to be described. Although three such blocks are provided in the embodiment according to FIG. their number is not limited to this. The receiver further comprises one similar to the series of FIG Row (array) of transducer elements A .. A connection B enables the interchangeable connection of a linear

or a sector scanning probe with the circuitry of the receiver. According to Fig. 4, amplifiers U1 - U12 are so designed that every four amplifiers form a set. Since the number of transducer elements A., as in

Fig. 1, is four, the same number of amplifiers, i.e. four amplifiers, are connected to each block, in order to process four-channel signals which are supplied via the connection B from the row of transducer elements A. IQ will be. These four-channel signals are sent in parallel to the three sets of amplifiers Ul - U4, U5 - U8 and U9 - U12 coupled and then to the relevant crosspoint switches of blocks transferred. The signals from the series of transducer elements A. decreasing and in , n create parallel relationship to the crosspoint switch The circuit is referred to below as the input circuit. The respective output terminals bl, b2 and b3 of the delay lines 10, 11 and 12 are connected to amplifiers Gl, G2 and G3, respectively. Two switches on SWl and SW2 each have two contact points V and

W on, while another switch SW3 has three contact points X, Y and Z. The output signal of the amplifier Gl is supplied to the contact point X of the switch SW2 via the contact point W of the switch SW1 and also that of the left terminal of the delay line 11 via the contact point V of the switch SW1. The output signal of the amplifier G2 is supplied not only to the contact point Y of the switch SW3 via the contact point W of the switch SW2 but also to the left terminal of the delay line 12 _{via the contact point on V of the switch SW2.} The output signal of the amplifier G3 is applied to the contact point Z of the switch SW3.

ge The following is the mode of operation of the device or Receiver with the structure of FIG. 4 described. First of all, it is assumed that the recipient according to Fig. 4 a probe for sector scanning connected

is. The sector scanning takes place literally Sector-wise or segment-wise sense, and its principle has already been explained with reference to FIG. 6. in the The following therefore describes the manner in which a sector scan is carried out by means of the device according to FIG. 4 is carried out. The switches SW1 and SW2 are switched to their contact points V, while the switch SW3 is thrown to the contact point Z. If a coming from point Pl Echo reaches transducer element A. first, it reaches transducer element A. last. To get the turn

A. To bring the incoming echo into phase, the receiver according to FIG. 4 will therefore switch to the one described below Operated wisely. The electrical signal coming from the transducer element A passes through the amplifier Ul and is then over the switching element of the crosspoint switch represented by the black point

30 routed to delay line 10. This signal then passes through the amplifier Gl, the contact point V of the switch SWl, the delay line 11, the amplifier G2, the contact point V of the switch SW2, the delay line 12 and the amplifier G3 in the order given to finally reach the point of contact Z of switch SW3 to reach. The electrical signal of the transducer element A2 is via the amplifier U6 and then via the switching element of the crosspoint switch indicated by the black dot

31 is introduced into the delay line 11. Then

this signal reaches the contact point Z of the switch SW3 via the delay lines 11 and 12. Das electrical signal from the transducer element A3 passes the amplifier Uli and is then transmitted through the Black dot indicated switching element of the crosspoint switch 32 is applied to the delay line 12. The electrical signal from the transducer element A4 reaches the contact point Z of the switch SW3 after

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Passage through the amplifier U12, the switching element of the crosspoint switch indicated by the black dot 32 and the delay line 12. There is no time delay in the final stage because the closed element is the tap in the output stage. Through the processes described the electrical signals from the transducer elements A1 - A4 are given the timing shown in FIG.

YQ granted delays so that the output signals picked up from contact point Z of switch SW3 are in phase or in phase. These time delays imparted to the signals are _{denoted by T 1, T 7} and T 1 in FIG. A sector scan of the type shown in FIG. 6 can be carried out at will by appropriately switching over the switching elements in the crosspoint switches 30-32 in the manner described.

When a probe for linear scanning is connected to the receiver of FIG. 4, it works Receiver in the manner described below. The arrangement of such a probe is already in advance has been explained with reference to FIGS. 1 and 2 and therefore does not need to be described in detail below to become. A linear scan can generally be viewed as a sector scan with very small scan angles will. This means that the echoes enter the transducer elements practically perpendicular to them.

₃ q run. With the receiver according to FIG. 4, linear scanning can of course also be carried out.

The following is an example of op operation in a dynamic focus mode with reference to FIG for achieving multiple focal points using a single scan line, in contrast for a simple linear scanning. According to

Fig. 7 reach the echoes from the points Fl - F3 / are at different depths on a scanning beam, the arrangement or number of the transducer elements A. _f while they propagate with the illustrated wavefront. The echoes reaching the transducer elements are slightly out of phase with one another. In addition, these phase relationships vary between different depths of the reflection points, such as the

^ q points Fl, F2 and F3. In the case of a receiver which has several focal points, the reflection source must therefore be clearly arranged on the scanning beam / ¹ . The ultrasonic beam emitted by the transducer element row A. is initially an echo from the nearest point

2g Fl reflected. Then this beam is continuous in the form of echoes at points F2 and F3 reflected. For this reason, the phase characteristic of the receiver must correspond to the distances to the points Fl, F2 and F3 or the return times of the echoes be replaced by other phase characteristics.

A dynamic focus scan in which the depth of focus (or focal length) falls to the one described Way is continuously exchanged for another, is in the receiver according to FIG. 4 on the following explained way carried out. In this case, the switches SW1 and SW2 are with their contact points W in the Circuit arrangement switched on. When the switching elements indicated by the small open circles in FIG the cross-point switches 30, 31 and 32 are closed, a signal S1 from which the delay line 10 and the crosspoint switches 30 containing block with the proviso that the focal point is at the nearby point Fl and thus there is a large phase difference. A signal S2 is from which the delay line 11 and the crosspoint switch 31 containing block in the

Obtained state in which the focal point is at point F2 shown in FIG. Eventually a signal S3 from the block comprising delay line 12 and crosspoint switch 32, assuming supplied that the focus is on the point F3 of FIG. This way you can go through continuous Moving the closed contact point from X to Z a composite containing the three focal points electrical signal can be obtained from the switch SW3. Evidently, in the case of the invention The arrangement does not limit the number of focal points to the three focal points described.

In Fig. 8 is another embodiment of the fiction according to the recipient. This receiver is suitable for intermediate or compound scanning and similar constructed like the receiver according to FIG. 4, only that the switch SW3 is omitted. The parts of Fig. 4 corresponding parts are given the same reference numerals as previously indicated and therefore no longer explained in detail.

How such an intermediate or compound scan works (intermediate scan) is described below with reference to FIGS. 9 and 10. The goodness of one Tomogram obtained by means of an ultrasonic diagnostic device can be obtained by increasing the number of scanning beams can be improved very effectively. There is, however, a certain oQ increase in this number Limit, due to the need for delivery of the tomograms on a real-time basis and under Taking into account the frame rate of the cathode ray tube, the speed of the acoustic waves Q ^ and other factors. This is the reason why this is here type of scan called "intermediate scan" has been developed. 9 illustrates a intermediate scan resembling a sector scan,

while Fig. 10 illustrates an intermediate scan similar to a linear scan. In Figs. 9 and the acoustic main beam El is shown in a solid line, while the acoustic Intermediate rays El 'and El "are shown in dashed lines are. These intermediate beams are created by shifting the scanning area slightly to the right or left reached opposite the main ray El. As a result, it actually belongs to the transducer element series A. The ultrasound beam emits a certain width, which is roughly beyond that indicated by the solid lines indicated direction extends. The acoustic intermediate rays shown in dashed lines are in the received echoes included or included; this increases the amount of image information and thus improving the quality of the image provided by the ultrasonic diagnostic device.

If, in the arrangement according to FIG. 8, the contact points B of the switches SW1 and SW2 and the switching elements of the crosspoint switches 30-32 indicated by the small circles are closed, the block comprising the delay line 10 and the crosspoint switch deliver a signal corresponding to the acoustic intermediate beam El ¹ , the block containing the delay line 11 and the crosspoint switch 31 a signal corresponding to the acoustic main beam El and the block containing the delay line 12 and the crosspoint switch 32 a signal corresponding to the acoustic intermediate beam El ". The output signals of these blocks are then separated to form a visible image processed, whereby the intermediate scanned images are made visible according to Fig. 9 and 10. The mode of operation in the event that the contact points V of the switches SW1 and SW2 are closed has already been described with reference to FIG

therefore not to be explained again in connection with FIG.

In addition to the type of scanning described, the inventive Receiver also includes an intermediate scan according to FIG. 11 and an oblique scan according to FIG. to execute.

YQ Fig. 13 illustrates another connection means for delay summing. The transducer elements, the input circuit, the crosspoint circuits or switches, etc. are omitted. The lines 5 drawn in solid lines in FIG. 13 are also present in the arrangements according to FIGS. 4 and 8. In addition to these lines, the lines shown in dashed lines in FIG. 13 can also be provided, in which case the scanning direction can be reversed.

According to the invention can thus with a single receiver every working method from linear scanning to Sektdrabtasting be performed. In addition, there are the delay lines and the crosspoint switches, respectively are inserted in the form of a block, these components are effectively used. In addition, several Echoes of different types are detected at the same time, so that great advantages are offered in this regard.

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Claims (4)

Claims Iy phase-controlled ultrasonic receiver, the one Series of transducer elements (A.) for emitting ultrasonic waves and for receiving the reflected ones Controls ultrasonic waves, converts the ultrasonic waves into electrical signals and the phases of these electrical signals are delayed and the signals are summed, characterized by a number of delay and Summing blocks, each of the signals from the transducer element series (A.) as a common input signal remove and each have a delay line (10), a set of amplifiers (Ul - U4) to take the input signals from the transducer element row (A.) and a crosspoint switch (30), which taps of the delay line (10) at least matrix-like with the set of amplifiers (Ul U4) Able to connect, include, and by switching (er) devices (SW1, SW2) for switching the relationship between the output signals (A1, S2, S3) of the blocks between parallel and series relationship. 2. Receiver according to claim 1, characterized in that the delay and summing blocks each Signals (Sl, S2, S3) deliver that in accordance with the respective positions (Fl, F2, F3) of on echo sources lying at different depths are set in phase. 3. Receiver according to claim 2, characterized in that the output signals (Sl - S3) are consecutive or are continuously removable from the blocks. 4. Receiver according to claim 1, characterized in that that signals (El, El ¹ , El ") of different directions (ungs) - c properties can be removed from the relevant blocks.