JPS6150620B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention electronically controls transmission and reception of ultrasonic waves,
The present invention relates to an ultrasonic device aimed at high-speed scanning. In recent years, ultrasonic diagnostic devices have been actively researched and developed due to the safety of ultrasonic waves to the human body. In particular, a so-called B scope that obtains tomographic images using ultrasound employs a method of electronically scanning ultrasound beams for the purpose of high-speed imaging. FIG. 1 shows a configuration for scanning an ultrasonic beam by linear electronic scanning, which has been conventionally used. Each element of a transducer 1 in which n ultrasonic transducers (hereinafter referred to as elements) are arranged in an array at a pitch of d is connected to a translation selection circuit 2. The translation selection circuit 2 operates to switch and connect the signal from the pulser 3 to a determined element in response to a signal from the control section 4. Here, the operation of the translation selection circuit 2 will be explained in some detail. The number of elements operating simultaneously is k (k=4 in FIG. 1). When operating element numbers #1 to #4 of the transducer 1, the translation selection circuit 2 selects the elements P1 to P4 of the pulser 3.
are connected to each element number #1 to #4. As a result, the ultrasonic beam can be focused at point R1 in FIG. 1 by the pulse from the pulser 3. When operating element numbers #2 to #5, P1 to P4 of the pulser 3 are connected to element numbers #2 to #5, respectively. This allows the ultrasound beam to be moved to point R2. Follow the same steps to direct the ultrasound beam along the array.
It is possible to scan from R1 to R _o-k+1 . Generally, when driving the i-th to k elements at the same time, the translation selection circuit 2 switches and connects P1 to Pk of the pulser 3 to element number i to i+k-1 of the transducer 1. It is something to do. Here, the operation of the pulser 3 will be briefly explained. The pulser 3 excites an ultrasonic transducer to generate ultrasonic waves, but at this time,
It is well known that an ultrasonic beam can be focused by controlling the excitation time of a pulsar. This situation is shown in FIG. When focusing at point A, that is, at a distance of lf from the center axis of the element using k elements, the excitation time of each element is controlled so that the ultrasonic waves emitted from each element have the same phase at the arc 00'. Just do it. This means that the distance between the straight line drawn from each element #1 to #k to point A and the receiving point of circular arc 00', d5 ₁ to d
By exciting by giving a lead time of 5k divided by the speed of sound (in practice, a time delay is given as you move toward the center, with both ends of the element as the reference).
Can focus ultrasound beams. For this reason, it is often used to excite each of P1 to Pk of the pulser 3 with a delay time. Since the present invention also aims at electronic scanning having such an electron focusing effect, the following description of the pulsar will be treated as having such a delay time. Now, FIG. 3 shows a conventional configuration for linear electronic scanning having the above-mentioned functions. n+k+ such that all elements (actually smaller than this number near both ends) are connected to the terminals of switch 2'.
One circuit of changeover switches is connected as shown in FIG. 3 to perform a translational switching operation. Such a configuration requires approximately (n-k+1)×k switch contacts, and is not practical when n and k are large. As a specific example, if the scanning area is selected to be 200 mm and the element pitch d = 0.5 mm, n = 400, and the total number of elements that are driven as one set at the same time is
If the number is 40, approximately 16,000 switching contacts will be required. For switching such a large number of elements, electrical matrix connections are usually used. This conventional example is shown in FIG. The number k of elements to be simultaneously driven (k=4 in FIG. 4) is selected in the column (or row, hereinafter the same) of the matrix. Switches S1 to Sn and elements #1 to #n are connected to locations corresponding to the intersections of the matrix.
An example of this operation will be briefly explained. When using elements #1 to #4 as scanning order 1, the corresponding switches S1 to S4 are closed and all the remaining switches are opened. A~
Connect P1 to P4 of the pulser to the D terminal. It is sufficient to drive the pulser in this state. Next, when using #2 to #5 as scanning order 2, only the switches S2 to S5 are closed, and the pulsers P4 and P are connected to terminals A to D.
Connect with 1, P2, and P3. By repeating the above procedure as shown in Table 1, the ultrasonic beam is distributed along the array R1, R as shown in Figure 1.
2...can scan to R _o-k+1 .

[Table] Although the conventional example has been explained above, in the configuration shown in FIG.
This can be significantly reduced compared to the conventional example shown in the figure. However, in the conventional configuration shown in FIG. 4, (1) the switches attached to each vibrator must operate independently; (2) The disadvantage of having to switch the pulsers cyclically is that each switch requires an independent control signal, and the number of control lines required is usually the number of vibrators, that is, n. The disadvantage of (2) is that since the pulsar is switched cyclically, k×k switch contacts are usually required. A sequence of this switching is shown in FIG. For this reason, the hardware is still too complicated for practical use. The present invention provides a configuration that eliminates the above drawbacks. The present invention will be described in detail below with reference to Examples. FIG. 6 shows an embodiment of the present invention. 2 times the number of elements k driven simultaneously as a set - 1
Select (2k-1) as the matrix column. In other words, Figure 6 is an example where k=4, and #1 is in the first row.
Connect elements #7 to switches S1 to S7, respectively. In the second line, the elements in the second half of the first line are duplicated and are set to #5 to #11 and switches S8 to S.
Connect 14. Thereafter, connect up to element n in the same manner. Next, the operation will be explained. First, the switches S1 to S7 in the first row are closed. Scan order 1 is A
~ Connect the pulsers P1 to P4 to the D terminal and drive the pulsers. In scanning order 2, pulsar P is connected to terminals B to E.
Connect 1 to P4. Similarly, up to scan order 4, it is sufficient to move only the pulser without changing the switch state. In scanning order 5, it is sufficient to return the pulsers to the initial state (pulsars P1 to P4 at terminals A to D), close the switches S8 to S14 in the second row, and repeat the same procedure. This scanning procedure is shown in Table 2.

[Table] By using such a connection means, the switches can be opened and closed in groups, and an independent control line for each element is not required, so the number of control lines can be significantly reduced. In FIG. 6, 2k-1 elements are used in the matrix columns, but this number may be any number greater than k. However, if this number becomes equal to n, the conventional configuration shown in FIG. 3 will result, and the desired effect will naturally not be achieved.
FIG. 7 shows columns with k=4 and number of columns=6, and Table 3 shows this scanning procedure.

[Table] Since the operation is the same as that shown in FIG. 6, the explanation of the operation will be omitted. Next, FIG. 8 shows an example in which the pulsers are switched and connected to the terminals A to F as shown in Table 3. As described above, the number of switching contacts of the pulser according to this embodiment is generally k×(m−
k+1), and if m is selected such that k<m<2k-1, it can be reduced compared to the conventional example shown in FIG. FIG. 9 shows an example of a specific switch circuit configuration corresponding to FIGS. 7 and 8. This is an example using an AND gate that allows wire-or. According to the scanning order at this time, the state of the switching signals of C1 to C6 is
Shown in the table. As is clear from these figures and tables, it can be seen that the total number of control signals for controlling the switches can be significantly reduced compared to the number of elements.

【table】

[Table] Next, let us compare the total number of contacts between the conventional example and the embodiment according to the present invention. In the conventional examples shown in FIGS. 4 and 5, the total number of contacts is generally (n+k×k) contacts,
In the present invention, it is n/k×m+k×(m−k+1). Let's apply the practical numerical example mentioned above to this. If n=400, k=40, and m=60, the number of contacts can be reduced to 2000 in the conventional example and 1640 in the present invention. In addition, the conventional method requires 400 control signal lines, but with this method, only 10 are required since it is n/k, which greatly simplifies the configuration of the device and brings great benefits. There is. In this description, the emission of the ultrasonic beam has been described, but the same applies to the case of receiving the ultrasonic beam by replacing the pulser with a phase matching circuit.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining linear electron scanning, Figure 2 is a diagram for explaining electron focus, and Figure 3 is a diagram for explaining electronic focus.
The figure shows an example of the conventional method, FIGS. 4 and 5 show another example of the conventional method, FIGS. 6 and 7 show an embodiment of the present invention, and FIGS. Figure 9 is
FIG. 8 is a diagram illustrating a main part of the embodiment related to FIG. 7;

Claims (1)

[Claims] 1. An ultrasonic device that performs electronic ultrasonic beam scanning by using k consecutive vibrators out of n transducers forming an array-type transducer, and electrically switching and shifting the set of sequentially used transducers. In the above, m consecutive oscillators with a number m where k<m<n are set as one group, and the oscillators are arranged so that the latter half (k-1) of the oscillators belonging to one group overlap in the next group. a first selection means for grouping and selecting one of these groups; and a first selection means for sequentially scanning and selecting k of the m transducers selected by the group selection means to perform intra-group scanning. 1. An ultrasound transducer control device, comprising two selection means, and scans an ultrasound beam by repeating intra-group scanning by the second selection means and group selection by the first selection means.