JP2766282B2 - Ultrasound diagnostic equipment - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial application field) The present invention relates to an ultrasonic diagnostic apparatus with an improved reception delay system.

(Prior Art) In the case of performing a sector-shaped scan by an electronic scan type ultrasonic diagnostic apparatus, a predetermined delay time is given to ultrasonic transducers of a plurality of channels so that a subject is superposed in a sector-like manner. A sound wave is transmitted, a delay time corresponding to a delay time at the time of transmission is given to an ultrasonic reception signal received by the same vibrating element, and phasing addition of reception signals of a plurality of channels is performed.

As an example of an ultrasonic diagnostic apparatus for performing such a reception delay, the present applicant has previously provided an apparatus as disclosed in Japanese Patent Application Laid-Open No. 61-162938. Figure 6 is shows an example thereof, the apparatus 1 through the analog switch to output to the corresponding tap 1 to n of the delay lines DL ₁ inputs a received signal of the M-channel ANS ₁₁ to ANS1M and Tmax / a delay processing section 10A of the first block delay time 2 is provided with a delay line DL ₁ is a delay means a given, M + 1 through 2M of the corresponding tap of the received signal inputted to the delay line DL ₂ Analog switches ANS _{21 to} ANS2M that output to 1 to n
Delay line DL as delay means provided with a delay time of Tmax / 2
A delay processing section 10B of the second block being and a _2, in both the delay processing section 10A, the fixed delay means for analog switches S ₀ and the delay time Tmax / 2 for switching processing an output signal from 10B is given and a fixed delay line DL _3, is constituted by an adder 11 for adding the output from the output signal analog switches S ₀ from the fixed delay line DL _3.

Next, the operation of the device having the above configuration will be described with reference to FIGS. 3 and 5 showing the relationship between the input channel and the delay time.
A description will be given also with reference to FIGS.

First, attention is paid to the half cycle (O to + θ) of the sector operation as shown in FIG. In this state, the analog switch
The S ₀ connects the switching control to the input terminal 12A to the output terminal 13B, to connect the input terminal 12B to the output terminal 13D.

At this time, the received signals from the respective vibrating elements of channels 1 to M are supplied to the analog switches ANS _{11 to} ANS of the first block.
It is switching control at a timing corresponding to the transmission timing for transmission by 1M, the terminals 1 to n, is sent to the delay line DL ₁ to obtain the tap 1 to n.

On the other hand, the received signals from the respective vibrating elements of the M + 1 to 2M channels are transmitted to the respective analog switches ANS _{21 to} ANS ₂₁ of the second block.
Is switching control at a timing corresponding to the transmission timing for transmission by NS2M, the terminals 1 to n, is sent to the delay line DL ₂ to obtain the tap 1 to n.

The received signals are subjected to phasing addition by the delay lines DL ₁ and DL ₂ , and delay times in the range of 0 to Tmax / 2 are given.
The phasing addition means that the phases of the received signals are added together. Delayed signal from the delay line DL ₂ of the second block is sent to the input terminal 12B, and input to the fixed delay lines DL ₃ via the output terminal 13D is given a further delay time Tmax / 2, where the adder 11 You.

As a result, for each reception signal from each of the vibrating elements in the M + 1 to 2M channels, a fixed delay time Tmax / 2 and a delay line DL ₂ due to the fixed delay line DL ₃ as shown by the hatched portion in FIG. And a delay time in the range of 0 to Tmax / 2 is superimposed, and the delay time from the minimum delay time 0 to the maximum delay time Tmax is given to the received signal from the 1 to 2 M-channel vibration element. Output signal is an adder
Sent from 11.

Next, attention is paid to a half cycle from 0 to -θ of sector scanning as shown in FIG. In this case an analog switch
The input terminal 12A to the output terminal 13A of S _0, for switching control of the analog switches S ₀ so that the input terminal 12B is connected to the output terminal 13C. 1 to M received signals from each transducer element of the channel switching controlled by the delay line DL by the analog switches ANS ₁₁ to ANS1M similarly to the case described above
Type _1, the delay time in the range of the delay line DL ₁ by 0 to Tmax / 2 is given to become a delay signal, the input terminal 12A, is sent to the fixed delay lines DL ₃ via the output terminal 13A. Then, the delay fixed delay lines DL ₃ through FIG. 5 predetermined delay time as indicated by the shaded portion of the relative signal Tmax / 2 is sent to the adder 11 after being superimposed.

On the other hand, the reception signals from the respective vibrating elements of the M + 1 to 2M channels are the delay lines of the second block in the same manner as described above.
A delay time in the range of 0 to Tmax / 2 is given by DL ₂ to become a delay signal, which is sent directly to the adder 11 via the input terminals 12B and 13C.

As a result, the adder 11 sends out an output signal in which a delay time from the maximum delay time Tmax to the minimum delay time 0 is given to the received signal from the 1 to 2 M-channel vibration element.

In this way, the analog switch AN with a small number of terminals
S ₁₁ to ANS1M, ANS ₂₁ through one cycle of the sector operation using ANS2M (O to theta, O or - [theta]) Kill to obtain an output signal given a predetermined delay time over.

However, the ultrasonic diagnostic apparatus of Figure 6, it is necessary to prepare a fixed delay lines DL ₃ in addition to the delay line DL _1, DL ₂ of the first and second, the cost is avoided since these delay lines are expensive There is a disadvantage that there is no. FIG. 7 shows another example of the prior art which solves such a disadvantage. Only a first and a second delay lines DL ₁ and DL ₂ are prepared and a reception channel group requiring a delay time of Tmax / 2 or more is required. The delay signal output from the delay line is input to the other delay line and fed back to add the two delay times to obtain a delay time characteristic as shown in FIG. 3 and FIG. Things. S ₁ , S ₂ ,
S ₃ is an analog switch.

(Problems to be Solved by the Invention) By the way, in the ultrasonic diagnostic apparatus as shown in FIG. 7, the delay signal, the frequency characteristic, the gain, and other characteristics of the first and second delay lines vary, so that the delay signal There is a problem that an error occurs depending on the direction in which the air flows.

The present invention has been made to solve the above problems,
It is an object of the present invention to provide an ultrasonic diagnostic apparatus that eliminates errors due to variations in delay time, frequency characteristics, gain, and the like even when two types of delay lines are used.

[Constitution of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a plurality of ultrasonic vibrators each including a first channel group and a second channel group; A driving unit for transmitting ultrasonic waves in a sector form from a child, a first delay unit and a second delay unit, and a delay time corresponding to a delay time at the time of transmission with respect to a received signal based on the transmitted ultrasonic wave. Providing delay means for inputting, a first received signal from an ultrasonic transducer of the first channel group and a second received signal from an ultrasonic transducer of the second channel group, The second received signal is sent to the second delay means, or the second received signal is sent to the second delay means, and the second received signal is sent to the second delay means. Switch to the first delay means according to the receiving beam direction And a delay signal output from the first delay means is input to the second delay signal, and the second delay means is used as a fixed delay means of the first delay means. And feedback means.

(Operation) The first and second two types of delay means are prepared,
The first received signal and the second received signal are inputted to one of the first and second delay means via a switch means which can be inputted to both of the first and second delay means in accordance with the direction of the receive beam, and the first delay signal is outputted. The delay signal output from the means is fed back so as to be always input to the second delay means. This allows the first or second reception signal to always flow in one direction from one delay unit to the other delay unit.
Errors due to variations in delay time, frequency characteristics, gain, and the like can be eliminated.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

Figure 1 is a circuit diagram showing an embodiment of an ultrasonic diagnostic apparatus of the present invention, ultrasonic transducer channels plurality (1 to 2M) is connected to the analog switch group S ₄ and S ₅ of the switching means You. Each analog switch group S _4, S ₅ and outputs to the analog switch ANS ₁₁ to ANS1M and ANS ₂₁ to ANS2M selects either of two input signals. The output side of the analog switch ANS ₁₁ to ANS1M the first below the first delay line DL ₁
Is connected to each of taps 1 to n of the analog switch ANS
The output side of the ₂₁ to ANS2M are connected to the taps 1 through n of the second delay line DL _2.

First delay line DL ₁ and the second delay line DL ₂ has a tap of 1 to n, the delay time of Tmax / 2 is given.

First output terminal 1 of the delay line DL ₁ is connected to a tap n of the second delay line DL _2. Thereby, the first delay line DL
_The delay signal output from ₁ is always input to the _second delay line DL2 so that one-way feedback is applied. That delay line DL ₂ second case of the present embodiment is utilized as a fixed delay line acting as the offset delay means is configured to obtain from the delay time of Tmax / 2.

 Next, the operation of the present embodiment will be described.

First analog switch group S _4, the input terminal 16A of S ₅ [(16A ₁
To 16AM) and (16A M + 1 to 16A2M)]
Connecting to A [(17A ₁ to 17 AM) and (17A M + 1 to 17A2M)]. This 1 to receive signal M is first desired delay processing is inputted to the corresponding tap of 1 to n of the delay lines DL ₁ through one of the analog switches ANS ₁₁ to ANS1M is being strained facilities output Is done. Subsequently, the delay signal is input from the output terminal 1 to the tap n of the second delay line DL ₂ , given a delay time of Tmax / 2, and output from the output terminal 2.

On the other hand, in this state, the received signals of M + 1 to 2M are:
Second delay line through the analog switch ANS ₂₁ to ANS2M
It is input to the corresponding taps 1 to n of DL ₂ , subjected to a desired delay processing, and output from the output terminal 2.

As a result, a signal received from the vibrating element of the channel 1 to 2M from the output terminal 2 is given a delay time from the maximum Tmax to the minimum 0 and corresponds to a half cycle of the sector scan in FIG. The delay processing having the delay time characteristic shown in FIG. Hatched portion indicates an offset delay time utilizing the second delay line DL ₂ as a fixed delay line.

Next, the input terminals 16B of the analog switch groups S ₄ and S ₅ [(16B ₁
To 16BM) and (16B M + 1 to 16B2M)]
To switch to B [(17B ₁ to 17BM) and (17B M + 1 to 17B2M)]. As a result, the received signals 1 to M are input to the _second delay line DL ₂ , subjected to desired delay processing, and output from the output terminal 2, contrary to the above. On the other hand, in this state, the received signals of M + 1 to 2M are input to the _first delay line DL1, contrary to the above, subjected to desired delay processing, and output. Subsequently, the delay signal is input from the output terminal 1 to the tap n of the _second delay line DL2,
The delay time of x / 2 is given and output from the output terminal 2.

As a result, a signal received from the vibrating element of the channel of 1 to 2M from the output terminal 2 is given a delay time from the maximum Tmax to the minimum 0, and corresponds to a half cycle of the sector scan in FIG. The delay processing having the delay time characteristic shown in FIG. Hatched portion indicates an offset delay time utilizing the second delay line DL ₂ as a fixed delay line.

According to this embodiment, two kinds of delay line of the first delay line DL ₁ and the second delay line DL ₂ were prepared, always the ultrasonic reception signals required for offset delay time 1 Delay line
Since the delay processing is performed by flowing in one direction from DL ₁ to the second delay line DL ₂ , the first and second delay lines DL ₁ and DL
₂ can eliminate errors in delay time due to variations in characteristics such as delay time, frequency characteristics, and gain.
The second delay line DL ₂ and the first delay line D
And toward the L ₁ strainer facilities delay processing by passing the received signal can also obtain the same effect. The offset delay time of the delay line used as the fixed delay line can be set in units of ΔT (unit delay time between taps) by arbitrarily selecting taps to which feedback is applied, thereby obtaining a fine delay time. be able to.

As described above, according to the present invention, the sector scan can be performed without preparing a dedicated delay line. Therefore, this principle is applied to a linear scan circuit having a delay line for setting a reception dynamic focus. This makes it possible to perform a sector scan also by this linear scan circuit. This makes it possible to realize a sector scan circuit while taking advantage of the low-cost, small-size linear scan circuit as it is.

[Effects of the Invention] As described above, according to the present invention, two types of delay means are provided, and switching means for inputting a plurality of received signals to any one of the delay means in accordance with a reception beam is provided. Since the delay processing is performed by feeding back the received signal only in one direction from one side to the other side, errors can be eliminated based on variations in characteristics such as delay time, frequency characteristics, and gain.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention, FIG. 2 is an explanatory diagram showing a received beam angle of 0 to + θ in a half cycle of a sector scan, and FIG. +
FIG. 4 is an explanatory diagram showing the delay time characteristic corresponding to θ, FIG. 4 is an explanatory diagram showing the received beam angles of 0 to −θ in the other half cycle of the sector scanning, and FIG. 5 is a diagram corresponding to 0 to −θ of the sector scanning. 6 and 7 are schematic diagrams showing a conventional example. ANS ₁₁ to ANS1M, ANS ₂₁ to ANS2M ...... analog switches, S _4, S ₅ ...... analog switch group, DL ₁ ...... first delay line DL ₂ ...... second delay line 16A, 16B ...... analog switch , Input terminals of 17A, 17B... Output terminals of an analog switch, 1... Output terminals of a first delay line, 2... Output terminals of a second delay line.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) A61B 8/00-8/14

Claims (1)

(57) [Claims] A plurality of ultrasonic transducers comprising a first channel group and a second channel group; driving means for transmitting ultrasonic waves in a sector form from the ultrasonic transducer; first delay means; A delay unit for providing a delay time corresponding to a delay time at the time of transmission to a received signal based on the transmitted ultrasonic wave; a first delay unit from the ultrasonic transducer of the first channel group; And the second received signal from the ultrasonic transducer of the second channel group are input, and the first received signal is sent to the first delay means, and the second received signal is sent to the second delay unit. Switching means for switching the first received signal to the second delay means, or for switching the second received signal to the first delay means in accordance with a receiving beam direction, and outputting the first received signal to the second delay means. The delay signal output from the first delay means 2nd
And the second delay means is connected to the first delay means.
An ultrasonic diagnostic apparatus comprising: a feedback unit that is used as a fixed delay unit of the delay unit.