JPS6158648A - Machine scanning type ultrasonic probe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a mechanical scanning ultrasonic probe used in connection with a medical ultrasonic diagnostic apparatus.

The configuration of the conventional example and its problems Figure 1 shows a conventional mechanical scanning ultrasonic probe (
A basic configuration diagram of the MSP (hereinafter abbreviated as MSP) is shown.

Three piezoelectric vibrators 1 rotate a rotor 2 installed at a predetermined angle (1200) in the direction shown in the figure around a rotation axis 3, transmit and receive ultrasonic waves 4 into a living body 6, and generate a fan-shaped Obtain an ultrasound tomogram. The rotor 2 is installed in an acoustic window material 6 made of resin, and a sound wave propagation medium 7 such as deaerated water is filled between the acoustic window material 6 and the rotor 2. Further, the drive unit 8 rotationally drives the rotor 2 via a belt or a gear 9. With this configuration, a sector-shaped tomographic image as shown in Figure 2 is displayed on the display unit (not shown) of the ultrasound diagnostic device, providing diagnostic information, but generally speaking, this MSP The plurality of piezoelectric vibrators 1 have the same curvature and aperture diameter, and transmit and receive focused ultrasonic beams as shown by diagonal lines in FIG. As is clear from FIG. 2, a relatively narrow ultrasonic beam is obtained in region B, but thicker ultrasonic beams are obtained in regions A (near distance) and C (long distance), resulting in a decrease in azimuth resolution. The decline in lateral resolution in the C region has been one of the biggest problems with conventional MSPs.

OBJECTS OF THE INVENTION The present invention provides a mechanical scanning ultrasound probe (MSP) that has almost the same lateral resolution over the entire scanning area, thereby solving the problem of the short range area, which is the biggest problem with conventional MSP. and to improve the decline in lateral resolution in long distance areas.

Structure of the Invention The present invention achieves the above object, and includes a support body that holds a plurality of piezoelectric vibrators and rotates or oscillates in a housing filled with a sound wave propagation medium. The present invention provides mechanical scanning ultrasonic probes with different distances.

DESCRIPTION OF THE EMBODIMENTS FIG. 3 shows an embodiment of a mechanical scanning ultrasonic probe (MSP) according to the present invention. have the same opening diameter,
Each lens is formed into a concave shape and has a focal length of fl.

f2. Three piezoelectric vibrators 10a, 10b, and 10c each having f3 are installed on the rotor 11 at an interval of 1200 mm.

The rotor 11 has a drive unit 12 composed of DC motors, etc.
Accordingly, it is rotationally driven by a transmission section 13 such as a belt or gears. Further, the rotor 11 is installed in an acoustic window material 14 made of polymethylpentene resin, and a sound wave propagation medium 15 such as deaerated water is filled between the rotor 11 and the acoustic window material 14.

The signal transmitter 16 is each piezoelectric vibrator 10a.

It connects 1ob, 1oc and the transmit/receive signal processing/display unit 17, and is composed of a slip ring or a rotary transformer. A rotation control 18 composed of an encoder or the like is used to control the rotation of the rotor 11, and is connected to a drive section 12 and a transmission section 19 such as a belt or gears.
connected with. Further, the signal transmitter 16. Drive part 1
29, the rotation control unit 18 is connected to the transmitting/receiving signal processing unit 6014 and the display unit 17 via the connection line 2o, respectively.
1 is a housing of the MSP. The transmission/reception signal processing/display section 17 has functions such as generation of transmission signals, amplification, detection, storage, reception signal processing such as scan conversion, generation of signals for various system control signals 5, and display on a CRT. .

Generally, the transmitting/receiving signal processing section is not included in the MSP.

The ultrasonic beam of MSP with the configuration shown in Fig. 3 is
Shown in Figures (a) and (b). In Figure 4 (,),
The broken line indicates the ultrasound beam obtained by the piezoelectric vibrator 10a with a focal length of fl, and the piezoelectric vibrator 1 with a focal length of f2
The ultrasonic beam obtained by the piezoelectric vibrator 1oC having a focal length of f3 is shown by the dashed-dotted line and the dashed-dotted line, respectively.

For each of these three ultrasound beams having different focal lengths, only the region where the narrowest beam can be obtained in overall □ is used. For example, the ultrasonic beam of the piezoelectric vibrator 10a having a focal length of fl covers two regions f'2.
The ultrasonic beams of the piezoelectric vibrators 10b and 10'c having a focal length of 'f3 are z2. Use Z3 area. As shown in FIG. 4(b), the resulting ultrasonic beam is a narrow beam extending from a short distance region to a long distance region. Selection of the ultrasound beam in a predetermined area is performed by transmitting/receiving signal processing and
Display unit 17. Specifically, in the first scan, a piezoelectric vibrator 10a with a focal length of fl is used, and z1
Receive and store area-only information. In the second scan, a piezoelectric vibrator 10b with a focal length of f2 is used to scan z
Information for only two areas is received and stored. Similarly, in the third scan, a piezoelectric vibrator 10c with a focal length of f3 is used.
is used to receive and store information only for the z3 area. One image is obtained through these three scanning cycles. For example, if the rotor 11 rotates at 600 rpm, the time required to obtain one complete image is 100 m.
5ec, and a fan-shaped tomographic image with a frame rate of 1oHz is obtained.

FIGS. 5(a) and 5(b) show ultrasonic beams based on the second embodiment. The difference from the above embodiment is that the three piezoelectric vibrators 22a, 22b, and 22c have different focal lengths and aperture diameters. The purpose of doing this is as clear from Figure 4(b).
This is to improve the slight decrease in azimuth resolution in the Z1 region when piezoelectric vibrators with the same aperture diameter are used, and the piezoelectric vibrator 22a that focuses on a closer point is used with a smaller aperture diameter. This is an example realized by doing the following. In FIG. 5(,), the broken line represents the ultrasonic beam of the piezoelectric vibrator 22a with the focal length fl and the smallest aperture diameter, and the ultrasonic beam of the piezoelectric vibrator 22b with the focal length f2 and the second largest aperture diameter is shown by the broken line. A piezoelectric vibrator 22 with a focal length of f3 and the largest aperture diameter is shown by a dashed line as a sound wave beam.
The ultrasonic beam of c is shown by a chain double-dashed line.

In this embodiment, as in the previous embodiment, by selecting the ultrasonic beam in a predetermined area by the transmitting/receiving signal processing/display unit 17, the entire area from short distance to long distance can be transmitted as shown in FIG. It is possible to obtain a narrow beam over a wide area and improve azimuth resolution.

Effects of the Invention In short, the present invention provides a mechanical scanning ultrasonic probe in which a plurality of piezoelectric vibrators having different focal lengths are held on a support body, and the support body is rotated or oscillated in a sound wave propagation medium. This technology improves the decline in azimuth resolution of MSP, especially in long-range areas, which has been pointed out as the biggest problem up until now, and provides good azimuth resolution over the entire fan-shaped scanning area. The resulting MSP was achieved.

[Brief explanation of the drawing]

Figure 1 is an overview of a conventional mechanical scanning ultrasound probe, Figure 2
The figure is an explanatory diagram of a fan-shaped tomographic image and an ultrasound beam, Figure 3 is an overview diagram of a mechanical scanning ultrasound probe in the first embodiment of the present invention, and Figures 4 (a) and (b) are FIGS. 6(a) and 6(b) are explanatory views of the ultrasonic beam according to the first embodiment, and FIGS. 6(a) and 6(b) are explanatory views of the ultrasonic beam according to the second embodiment. 10a, 1 ob, 10cm--1 piezoelectric vibrator, 11...rotor, 14...acoustic window material, 15...-
Sound wave propagation medium, 12...-driver, 13.19...
...Transmission section, 16--Signal transmitter, 17...-Transmission/reception signal processing/display section, 18...Rotation control section, 2o...
... Connection wire, 21 ... Housing. Figure 3? ! Figure 4<a,) Cb)? Yokosho G1-58648 (4) Figure 5 ((L) (1))

Claims (2)

[Claims] (1) A plurality of piezoelectric vibrators, a support body that holds the piezoelectric vibrators and rotates or oscillates, a housing that includes at least the support body and is filled with a sound wave propagation medium; What is claimed is: 1. A mechanical scanning ultrasonic probe comprising an acoustic window provided in at least a portion of the probe, the piezoelectric transducers having different focal lengths. (2) The mechanical scanning ultrasonic probe according to claim 1, wherein a plurality of piezoelectric transducers are arranged such that the shorter the focal length, the smaller the aperture diameter.