JP2560751B2 - Ultrasonic probe - Google Patents

Description

The present invention relates to an ultrasonic probe capable of improving the degree of focusing of an ultrasonic beam.

(B) Conventional technology and its problems In order to improve the directivity of the ultrasonic beam and improve the resolution, it is necessary to three-dimensionally focus the ultrasonic beam at a predetermined depth position in the subject. In order to focus the ultrasonic beam, use of an acoustic lens or application of the dynamic focus method that synthesizes the wavefront by exciting drive by giving a predetermined delay time to each transducer arrayed is considered. To be In the prior art, as shown in FIG.
By combining the two, the dynamic focus method is applied in the array arrangement direction (symbol x direction) of the transducer a, while the acoustic lens b is provided in the width direction (symbol y direction) orthogonal thereto. Each ultrasonic beam is focused.

However, conventionally, since the focus f _{1 of} the acoustic lens b is fixed, the ultrasonic beam can be focused only at a certain depth position. On the other hand, if the dynamic focus method is applied, the focus f ₂ can be arbitrarily changed by adjusting the delay time given to each transducer a, but the ultrasonic beam is focused only in the array arrangement direction (x direction). I can't. Therefore, the respective focus points in the directions (x direction and y direction) orthogonal to each other
It was not possible to adjust f ₁ and f ₂ so as to match at any depth position within the subject. For this reason, the degree of focusing of the ultrasonic beam was insufficient, and an image with sufficient resolution could not be obtained yet.

As a countermeasure against this, conventionally, the transducers are two-dimensionally arranged in a matrix and the delay time is set in each of the row and column directions to focus the ultrasonic beam three-dimensionally.
A three-dimensional array type ultrasonic probe has been studied, but it has not been put to practical use because of various problems in the wiring method of the lead wire connected to the electrode of each transducer and the control method of the delay time.

The present invention has been made in view of the above circumstances, and enables the focus of an ultrasonic beam to be adjusted in each of two directions orthogonal to each other so that a diagnostic image with enhanced resolution can be obtained. With the goal.

(C) Means for Solving Problems The present invention adopts the following configuration in order to solve the above-mentioned object.

That is, the ultrasonic probe of the present invention is arranged in an array, and transmits and receives ultrasonic beams, and a plurality of arrayed transducer groups for focusing the transmitted and received ultrasonic beams in the array array direction by the dynamic focus method. An acoustic lens that focuses the ultrasonic beam in a direction orthogonal to the direction in which the ultrasonic beams are focused by the transducer group, and a direction that separates at least one of the acoustic lenses from another acoustic lens. Drive mechanism for adjusting the focal position of the ultrasonic beam by moving the ultrasonic beam and the focal position of the ultrasonic beam by the transducer group and the focal position of the ultrasonic beam by the acoustic lens match at any depth position. And a position control circuit for controlling the position of the acoustic lens via the drive mechanism.

(D) Action When the drive mechanism is activated by the control signal from the position control circuit, at least one of the plurality of acoustic lenses approaches or separates from other acoustic lenses, and the focal position changes accordingly. To do. Therefore, the focus of the ultrasonic beam can be arbitrarily set not only in the array array direction of the transducers but also in the direction orthogonal thereto.

Then, if the focal point adjusted by the acoustic lens is adjusted to match the focal point that is dynamically focused, the focusing degree of the ultrasonic beam is further improved.

(E) Example FIG. 1 is a vertical sectional view of an ultrasonic probe of the present invention.

The ultrasonic probe 1 of this embodiment includes a plurality (three in this example) of acoustic lenses 4 for focusing an ultrasonic beam in a direction orthogonal to the array direction of a large number of transducers 2 arranged in an array. 6 and 8. These acoustic lenses 4, 6,
Of the eight, the upper and lower acoustic lenses 4 and 8 are convex lenses, and both are fixed to the frame 10. In addition, the intermediate acoustic lens 6 is a concave lens, and a support tool is provided on both sides thereof.
12a and 12b are attached. And one support
The reference numeral 12a is slidably fitted into a guide groove 16 formed in the frame 10, while the other support tool 12b is screwed onto a screw shaft 14, and the screw shaft 14 is connected to a pulse motor 16. Then, the screw shaft 14 and the pulse motor 16 constitute a drive mechanism 24 for moving the intermediate acoustic lens 6 close to and away from the upper and lower acoustic lenses 4 and 8. Further, the pulse motor 16 is connected with a position control circuit 18 for controlling the position of the intermediate acoustic lens 6. Reference numeral 20 is an acoustic matching layer arranged between the vibrator 2 and the upper acoustic lens 4, and 22 is a gel-like ultrasonic sound transmission medium filled between the acoustic lenses 4, 6 and 8.

Therefore, in the above configuration, when the focus position is set to the position control circuit 18, a control signal corresponding to the set focus position is output from the position control circuit 18, and the control signal causes the pulse motor 16 to rotate by a predetermined amount. As a result, the screw shaft 14 rotates, and accordingly, the intermediate acoustic lens 6 approaches or separates from the other acoustic lenses 4 and 8, and as a result, the focal position changes. In this example, the focal length becomes longer as the intermediate acoustic lens 6 approaches the upper acoustic lens 4, and conversely the focal length becomes shorter as the intermediate acoustic lens 6 approaches the lower acoustic lens 8 side.

On the other hand, since the dynamic focus method is applied to the focus of the transducers in the array direction as in the conventional case, the focus of the acoustic lenses 4 to 8 is determined by the position control circuit 18 based on the focus information set by the dynamic focus. By controlling the distance, it becomes possible to match the focal points in the orthogonal directions at arbitrary depth positions in the subject, and the degree of focusing of the ultrasonic beam is improved.

In this embodiment, the three acoustic lenses 4, 6, 8 are used.
However, the present invention is not limited to this, and may be a combination of two acoustic lenses, or may be a configuration in which a larger number of acoustic lenses are combined.

Further, in addition to the case of this embodiment, by applying the multi-stage focus method in which the focus position is changed in a time-division manner, the resolution at the time of multi-stage focus can be improved by interlocking the acoustic lens 6 according to the focus change. .

(F) Effect According to the present invention, the focal point of the ultrasonic beam can be arbitrarily set not only in the array arrangement direction of the transducers but also in the direction orthogonal to the array arrangement direction. Therefore, it is possible to improve the degree of focusing of the ultrasonic beam by making the focus focused dynamically and the focus adjusted by the acoustic lens, and as a result, a diagnostic image with a high resolution can be obtained as in the past. Excellent effects such as

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an ultrasonic probe according to an embodiment of the present invention, and FIG. 2 is an explanatory view showing a conventional focus position control method. 1 ... Ultrasonic probe, 2 ... Transducer, 4, 6, 8 ... Acoustic lens, 18 ... Position control circuit, 24 ... Drive mechanism.

Claims (1)

(57) [Claims] 1. An array of transducers for transmitting and receiving ultrasonic beams in an array and focusing the transmitting and receiving ultrasonic beams in an array array direction by a dynamic focus method, and a plurality of transducers arranged to array the ultrasonic beams. An acoustic lens for focusing in a direction orthogonal to the focusing direction of the ultrasonic beam by the transducer group, and at least one of the acoustic lenses is moved in a direction in which the acoustic lens is close to and away from another acoustic lens, A driving mechanism that adjusts the focal position of the beam, and the driving mechanism so that the focal position of the ultrasonic beam by the transducer group and the focal position of the ultrasonic beam by the acoustic lens match at any depth position. An ultrasonic probe comprising: a position control circuit that controls the position of the acoustic lens.