JP2000060850A - Ultrasonograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously form plural transmission beams without the need of a special driver. SOLUTION: An array vibrator 10 is constituted of plural vibration elements 10a and the vibration elements 10a are grouped into two groups A and B. Transmission circuits 20 and 22 are provided corresponding to the respective groups and the two transmission beams are simultaneously formed by utilizing the respective groups. Band-pass filters 26 and 28 are means for separating and extracting reception signals corresponding to the respective transmission beams.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus capable of forming a plurality of transmission beams.

[0002]

2. Description of the Related Art In an ultrasonic diagnostic apparatus, multi-stage focusing is performed in order to improve the quality of ultrasonic images. That is, the focus points are set to different depths in one transmission / reception. For example, at the time of reception, the received signals received by the respective vibrating elements are phased and added. At this time, if the delay amount for each received signal is changed stepwise, reception multi-step focusing can be realized. Further, reception dynamic focus is known as a method of continuously switching. On the other hand, when sending, generally 1
Only one transmit beam can be formed per transmission.
To that extent, there is a problem in that multi-stage focusing cannot be realized.

Japanese Unexamined Patent Publication No. 4-108439 discloses a technique in which an ultrasonic pulse having a high frequency is transmitted immediately after an ultrasonic pulse having a low frequency is transmitted to form two transmission beams substantially at the same time. There is. In addition, JP-A-8-3
Japanese Patent No. 8473 discloses a technique of forming two transmission beams at the same time by combining two frequency signals and supplying a transmission signal to a transducer.

[0004]

However, in the case of the device disclosed in Japanese Patent Laid-Open No. 4-108439,
Strictly speaking, two transmission beams are not formed at the same time,
The problem of time lag arises. Therefore, there is a problem that the time difference must be compensated for at the time of reception. Further, in the case of the device described in Japanese Patent Application Laid-Open No. 8-38473, it is necessary to use a high voltage type linear amplifier as a driver provided in the preceding stage of the vibrator, and it is impossible to use a simple switching element. There's a problem.

The present invention has been made in view of the above conventional problems, and an object thereof is to simultaneously form a plurality of transmission beams in an ultrasonic diagnostic apparatus without requiring a special driver or the like. .

[0006]

In order to achieve the above object, the present invention provides an array transducer which is composed of a plurality of vibrating elements and which transmits and receives ultrasonic waves, and a plurality of transmission beams by one transmission. In order to form the plurality of vibrating elements into a plurality of groups, a plurality of transmitting circuits for supplying ultrasonic waves of different frequencies for each group, and a reception signal output from the array transducer for each group. And a image forming unit that forms an ultrasonic image using the plurality of received signals after the separation.

With the above arrangement, the plurality of vibrating elements are divided into a plurality of groups at the time of transmission, and a transmission beam is formed by using each group. In this case, ultrasonic pulses having different frequencies are used.

In processing the received signals, the received signals of each group are separated by using the difference in frequency, and an ultrasonic image is formed by using these received signals. In that case, they are selected or combined and used according to the property of each received signal, and when forming one ultrasonic image, different received signals are used for short distance and long distance, for example.

Preferably, the plurality of transmission beams are formed to have different focus depths, or the plurality of transmission beams are formed to have different azimuth directions.

Preferably, the separating means is composed of a plurality of band pass filters, or the separating means is composed of a quadrature detector provided for each group, and each quadrature detector is provided for each group. A reference signal having a frequency corresponding to the transmission frequency is supplied.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a preferred embodiment of the ultrasonic diagnostic apparatus according to the present invention, and FIG. 1 is a block diagram showing the overall structure thereof.

The array transducer 10 is built in, for example, an ultrasonic probe. The array transducer 10 is composed of a plurality of (for example, 100) vibrating elements 10a arranged in an array. A transmission unit 16 is connected to the array transducer 10 via a selection circuit 12 and a driver 14.
The selection circuit 12 transmits the array unit 10 to the transmission unit 16
Alternatively, it is a circuit that switches the receiving unit 24. Driver 14
Is a circuit that amplifies the transmission pulse output from the transmission unit 16 for each vibrating element 10a. In this embodiment,
As the driver 14, a normal switching circuit that generates a high voltage pulse by inputting a low voltage pulse is used.

The transmitting unit 16 has transmitting circuits 20 and 22 in this embodiment. Each transmission circuit 20 and 22
Have a function of forming a transmission beam, respectively.
Specifically, each of the transmission circuits 20 and 22 has a delay circuit provided for each vibrating element 10a, and electronically transmits by transmitting a transmission signal with a predetermined delay amount to each vibrating element. It forms a beam. In the present embodiment, the transmission circuits 20 and 22 form different transmission beams.

FIG. 2 shows two transmission beams A and B formed by the array transducer 10. That is, the ultrasonic beam A is formed by focusing the ultrasonic waves on the focus point F1, and the transmission beam B is formed by focusing the ultrasonic waves on the focus point F2.

In this case, in this embodiment, one transmission beam is formed by using the odd-numbered vibration elements 10a, and the other transmission beam is formed by using the even-numbered vibration elements 10a. Therefore, two transmission circuits 20 and 22 are provided corresponding to such two transmission beams.

As can be understood from the above description, the transmission section 16 is connected to all the vibration elements 10a, but these vibration elements 10a are divided into two groups in this embodiment, and each group is divided into two groups. A transmission circuit is provided for each. Of course, as will be described later, in order to separate and extract the reception signals corresponding to the respective transmission beams at the time of reception, ultrasonic pulses having different frequencies are used in forming the respective transmission beams. Specifically, f1 is set as the transmission center frequency for group A, and f2 is set as the transmission center frequency for group B.

Therefore, in the above embodiment, 2
Although one transmission beam was formed at the same time, when three transmission beams are formed at the same time, the array transducer 10 may be divided into three groups, and three transmission circuits may be provided correspondingly. .

In the above embodiment, the plurality of vibrating elements 10a are divided into odd-numbered and even-numbered groups, but as shown in FIG. 3, they are divided into right and left groups. You can go. The grouping can be appropriately set based on the relationship such as the aperture and the resolution during transmission.

A plurality of reception signals from the array transducer are input to the receiving section 24 via the selection circuit 12. The receiving unit 24 is a circuit that executes so-called phasing addition, and specifically includes an amplifier provided for each vibrating element, a delay circuit, and an addition circuit that adds delayed signals. By the way, in the present embodiment, the reception dynamic focus is realized by the action of the receiving unit 24.

That is, at the time of transmission, the transmission multi-step focus as shown in FIG. 2 is executed, and at the time of reception, the reception dynamic focus or the reception multi-step focus is executed. This makes it possible to improve the image quality of the ultrasonic image from a short distance to a long distance, as will be described later.

The received signal output from the receiver 24 is input to bandpass filters (BPF) 26 and 28. The band-pass filters 26 and 28 are provided corresponding to the respective transmission center frequencies, and the band-pass filters 26 and 28 can separate and extract the reception signal for each transmission beam.

The received signal that has passed through the bandpass filters 26 and 28 is sent to the image forming section 30. The image forming unit 30 forms an ultrasonic image by selecting or synthesizing the received signals based on the characteristics of the received signals. For example, in that case, the reception signal corresponding to the transmission beam A is used when forming a short-distance image, and the reception signal corresponding to the transmission beam B is used when forming a long-distance image. The ultrasonic image formed as described above is sent to the display unit 32 and an image is displayed.

The configuration shown in FIG. 1 can be used when various electronic scanning methods such as electronic linear scanning and electronic sector scanning are applied. Further, in the above embodiment, only the depth of the focus point is different between the transmission beams as shown in FIG. 2, but the beam azimuths may be different.

FIG. 4 shows another example of the configuration for separating and extracting the received signal for each transmission beam. In this example, the received signal is input to the two quadrature detectors 40 and 42. The quadrature detectors 40 and 42 each have 2
It has one mixer and a low-pass filter, and the reference signal is mixed with the received signal in each mixer. In this case, the quadrature detector 40 is supplied with the reference signal corresponding to the transmission center frequency f1, and the quadrature detector 42 is supplied with the reference signal corresponding to the transmission frequency f2.

The complex signals output from the quadrature detectors 40 and 42 are input to amplitude calculators 44 and 46, respectively, and the amplitudes are calculated by calculating the square roots of the squares of the real part and the imaginary part. The calculation result is sent to the image forming unit 30.

[0027]

As described above, according to the present invention,
It is possible to form a plurality of transmission beams at the same time without requiring a special driver or the like.

[Brief description of drawings]

FIG. 1 is a block diagram showing a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention.

FIG. 2 is a conceptual diagram showing two transmission beams.

FIG. 3 is a diagram showing another example of grouping.

FIG. 4 is a diagram showing another configuration example for separating and extracting a reception signal corresponding to each transmission beam.

[Explanation of symbols]

10 array transducer, 12 selection circuit, 14 driver, 16 transmitter, 20, 22 transmitter, 24 receiver, 26, 28 bandpass filter (BPF), 30
Image forming unit, 32 display unit.

Continued front page    F term (reference) 4C301 AA02 BB01 BB02 BB23 EE15                       EE17 GB02 GB03 HH25 HH37                       HH38 HH46 HH48 HH54 HH56                       JB29 JB38 JB42

Claims (5)

[Claims] 1. An array transducer comprising a plurality of vibrating elements for transmitting and receiving ultrasonic waves; and a plurality of vibrating elements divided into a plurality of groups in order to form a plurality of transmission beams by one transmission. A plurality of transmitting circuits that supply ultrasonic waves of different frequencies to each group, a separating unit that separates a received signal output from the array transducer into a received signal of each group, and a plurality of the separated circuits. An ultrasonic diagnostic apparatus comprising: an image forming unit that forms an ultrasonic image by using a received signal. 2. The ultrasonic diagnostic apparatus according to claim 1, wherein the plurality of transmission beams are formed to have different focus depths. 3. The ultrasonic diagnostic apparatus according to claim 1, wherein the plurality of transmission beams are formed in different azimuth directions. 4. The ultrasonic diagnostic apparatus according to claim 1, wherein the separating unit is composed of a plurality of bandpass filters. 5. The apparatus according to claim 1, wherein the separating means is composed of a quadrature detector provided for each group, and each quadrature detector has a frequency corresponding to a transmission frequency of each group. An ultrasonic diagnostic apparatus characterized in that a reference signal is supplied.