JPH0127741B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a technology for an ultrasonic diagnostic device that obtains biological information by emitting ultrasonic waves into a living body and detecting reflected signals of the ultrasonic waves from inside the living body. Belongs to a field.

[Technical background of the invention and its problems]

Conventionally, ultrasonic diagnostic equipment displays tomographic images of a living body using reflected signals that cannot be obtained by scanning the inside of a living body with an ultrasound beam.As the number of scanning lines increases to improve image quality, the number of frames decreases and real-time As a proposal to solve the problem of lack of sex, there is an invention described in Japanese Patent Publication No. 20017 of 1981.

The invention, as shown in FIG.
The reception directivity of the ultrasonic beam T emitted by exciting the ultrasonic transducers up to #5 is
By simultaneously receiving reflected echoes with ultrasonic transducers #1 to #5 so that R _A and R _B , the overall directivity of transmitting and receiving is in two different directions: TR _A direction and TR _B direction. Assume that it is possible to simultaneously obtain ultrasonic reflection signals from

In this way, in order to set two different reception directivity R _A and R _B for one transmission directivity T,
Two types of delay times must be set for ultrasonic transducers #1 to #5 during reception. For this reason,
Two delay circuits T _A1 , T _B1 - T _A5 , T _B5 are connected to each of the ultrasonic transducers #1 to #5. The delay circuits T _A1 to _{T A5} are for setting the delay time for receiving directivity R _A , and the delay circuits T _B1
~T _B5 is for setting the delay time to be the reception directivity R _B. And ultrasonic transducer #1
~The reflected signal received by #5 is sent to the delay circuit T _A1 ~
By performing addition processing in the first adder S1 via T _A5 , it is possible to obtain a reflected signal from the directivity _TRA direction of the total transmission and reception. In addition, the reflected signals received by ultrasonic transducers #1 to #5 are transferred to a delay circuit.
By performing addition processing in the second adder _S2 via T _B1 to T _B5 , it is possible to obtain a reflected signal from the directivity TR _B direction of the total transmission and reception.

However, according to the above method, two independent systems of delay circuits are required. Generally, the reception directivity is not necessarily set to two types, so delay elements having the same delay capability are required for the number of directions for simultaneous reception. For this reason, when there are many directions to receive simultaneously, or when it is necessary to deflect the ultrasonic beam significantly such as in sector scanning, it is necessary to use a large number of expensive long-time delay elements that occupy a large volume. As a result, manufacturing costs are high and the size of the device is increased.

[Purpose of the invention]

This invention has been made in view of the above circumstances, and even when obtaining multiple ultrasonic reflection signals with different directivity at the same time, it is possible to reduce the required number of delay elements, thereby reducing manufacturing costs. It is an object of the present invention to provide an ultrasonic diagnostic device that can reduce the amount of noise and make the device smaller.

[Summary of the invention]

The outline of this invention for achieving the above object is as follows:
Using one set of ultrasonic transducers sequentially selected from a plurality of ultrasonic transducers arranged in an array, a plurality of reception directivities are set for the transmitted ultrasonic beam, and multiple ultrasonic waves are reflected at the same time. In an ultrasonic diagnostic apparatus for obtaining a signal, a first delay circuit having a large delay amount connected in series so as to input the reflected signal from each of the ultrasonic transducers, and a delay amount having output terminals as many as the number of simultaneous receptions. The present invention is characterized in that it includes at least two stages of delay circuits including a second delay circuit having a small delay circuit.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a schematic explanatory diagram showing an ultrasonic transducer and a transmitting/receiving circuit in an ultrasonic diagnostic apparatus that is an embodiment of the present invention.

In FIG. 2, ultrasonic transducers #1 to #5 are
In an ultrasonic probe (not shown), five adjacent elements of ultrasonic transducers arranged in an array are shown. First delay circuits T ₁₁ to T ₁₅ that can set a delay time with a large amount of delay are connected to these ultrasonic transducers #1 to #5, respectively.
The first delay circuits T ₁₁ to _{T 15} are also used as delay means for transmission and reception, and when transmitting, input a reference signal (not shown) and delay it so that the transmission directivity is in the T direction shown in the diagram. Then, the ultrasonic transducers #1 to #5 are excited.
Furthermore, during reception, the ultrasonic transducers #1 to
The reflected signals from #5 are output after being delayed by the same amount of time as when they were transmitted. First delay circuit T ₁₁
The output terminals of T ₁₅ are respectively connected to the input terminals of second delay circuits T ₂₁ to _{T 25} that can set delay times with small delay amounts. Said second delay circuit T ₂₁
consists of a delay element _l1 and a multiplexer mp1 for selecting the tap of this delay element _l1 . For example, the multiplexer mp1 has a receiving directivity characteristic of 2
When setting in the direction, as shown in Figure 3,
It consists of a first multiplexer M1 and a second multiplexer M2, each having its input terminal connected to the tap terminal of the delay element _l1 . other second
The delay circuits T ₂₂ to T ₂₅ also correspond to the second delay circuit T ₂₁ .
Similarly, delay elements l ₂ to _{l 5} and multiplexer mp2
~mp5, multiplexer mp2~mp
5 has the same configuration as the multiplexer mp1.

The first and second adders S1 and S2 input the outputs of the second delay circuits _T21 to _T25 , add them, and output the result. The first adder S1 is
The output of the first multiplexer M1 among the multiplexers mp1 to mp5 is input. The second adder S2 includes a second multiplexer M in the multiplexers mp1 to mp5.
It is designed to input the output of 2. The delay circuits T and T' connected after the first and second adders S1 and S2, when deflecting the transmission directivity,
This is to correct image distortion caused by the arcuate movement of the focus point, and is designed to provide a delay time so that the focus point becomes horizontal regardless of the direction of directivity.

The operation of the ultrasonic diagnostic apparatus configured as above will be explained. First, the first delay circuit T ₁₁ ~
At _T15 , ultrasonic transducers #1 to #5 are excited by a signal obtained by delaying a reference signal (not shown), and an ultrasonic beam is emitted such that the transmission directivity is in the T direction shown in the drawing. This reflected wave is received by the ultrasonic transducers #1 to #5, and a reflected signal is output. This reflected signal is transmitted to the first delay circuits T ₁₁ to T ₁₅
At this point, the signal is held for the same delay time as when it was sent and then output. The reflected signals output from the first delay circuits T ₁₁ to _{T 15} are then transmitted to the second delay circuits T ₂₁ to T 15 .
Enter _T25 . The multiplexers mp1 to mp5 in the second delay circuits _T21 to _T25 can be configured by selecting the tap terminals of the delay elements _l1 to _l5 , respectively.
In addition to the delay times given by the first delay circuits T ₁₁ to T ₁₅ , reflected signals are output that hold two types of minute delay times. That is, the multiplexer
First multiplexer M1 in mp1 to mp5
The delay elements l 1 _{to l 5} are arranged such that the first and second delay circuits cause the reception directivity to be in the direction R _A shown in the figure.
Select the tap terminal and output. Further, the second multiplexer M2 in the multiplexers mp1 to mp5 connects the tap terminals _l1 to _l5 so that the reception directivity is in the R _B direction shown in the figure by the first and second delay circuits. Select. Therefore,
For the transmitting directivity characteristic T, the receiving directivity characteristic is R _A , R _B
Therefore, the overall directional characteristics of transmitting and receiving can be set as TR _A and TR _B between them. At this time, since there is a slight deviation between focuses A and B during reception with respect to focus point C during transmission, the delay elements of the first delay circuits T ₁₁ to _{T 15} that set focus point C are , the delay elements l ₁ to _{l 5} of the second delay circuits T ₂₁ to _{T 25} may have a small delay amount. Therefore, the number of delay elements with a large amount of delay can be reduced compared to the case where large-scale delay circuits are used for the number of directions for simultaneous reception.

It goes without saying that the present invention is not limited to the embodiments described above, and includes various modifications within the scope of the gist of the invention. For example, if the amount of minute delay or the number of simultaneous receptions for multiple reception directivity is fixed, the second delay circuit is constructed using fixed delay elements l ₁ to l with taps as shown in Fig. 4. It can be easily configured with only ₅ . In this case, if the taps corresponding to the number of simultaneous receptions are connected to adders arranged as many times as the number of simultaneous receptions, the same effect as described above can be achieved with a simple configuration. Further, the present invention can be applied even when a reflected signal is digitized. For example, as shown in Figure 5,
A/D converts the reflected signals from ultrasonic transducers #1 to #5 into, for example, 8-bit digital signals.
Converters AD1 to AD5 are arranged, and the first
delay circuits T ₁₁ ′ to T ₁₅ ′ and second delay circuits T ₂₁ ′ to
Place T ₂₅ ′. In this case, an 8-bit counter or a shift register may be used as the delay element in the first and second delay circuits. In the embodiment described above, the number of simultaneous receptions is set to two for convenience of explanation, but it goes without saying that the number of simultaneous receptions can be three or more. On this occasion,
The taps of the delay elements may be selected so that the output of the second delay circuit is equal to the number of simultaneous receptions.
Further, the present invention can be applied not only to receiving reflected ultrasonic signals but also to receiving transmitted signals.

〔Effect of the invention〕

As explained above, according to the present invention, even when a plurality of reception directivities are set for a transmitted ultrasonic beam and a plurality of ultrasonic reflection signals are obtained at the same time, a plurality of receiving systems can be formed. It is possible to provide an ultrasonic diagnostic apparatus that can reduce the number of delay elements with a large amount of delay. Therefore, by reducing the number of delay elements that are expensive and occupy a large volume, it is possible to reduce manufacturing costs and downsize the device.In particular, by applying it to sectors such as sector scanning, which has a large amount of delay, The effect will be extremely large.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a conventional ultrasonic diagnostic apparatus when the directivity of simultaneous reception is set in two directions, FIG. 2 is a schematic explanatory diagram of an ultrasonic diagnostic apparatus that is an embodiment of the present invention, and FIG. The figure is a schematic explanatory diagram showing an example of the configuration of a multiplexer in the second delay circuit, FIG. 4 is a schematic explanatory diagram showing a modification example when the second delay circuit is a fixed delay element, and FIG. FIG. 4 is a schematic explanatory diagram showing a modification example in which the data is digitized. #1 to #5... Ultrasonic transducer, T ₁₁ to _{T 15} ...
First delay circuit, T ₂₁ to T ₂₅ ... second delay circuit,
_l1 to _l5 ...delay element, mp1 to mp5...multiplexer, M1...first multiplexer, M2...
...Second multiplexer.

Claims (1)

[Claims] 1. Using one set of ultrasonic transducers sequentially selected from a plurality of ultrasonic transducers arranged in an array, a plurality of reception directivities are set for the transmitted ultrasonic beam. , in an ultrasonic diagnostic apparatus that simultaneously obtains a plurality of ultrasound reflected signals, a first delay circuit having a large amount of delay is connected in series to input the reflected signals from each ultrasound transducer, and the number of simultaneous receptions is An ultrasonic diagnostic apparatus comprising at least a two-stage delay circuit including a second delay circuit having an output terminal and having a small delay amount. 2. The ultrasonic diagnostic apparatus according to claim 1, wherein the second delay circuit has a variable delay time.