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Vote-"Specification 1, Title of Invention"
Ultrasound + Uzuki Tsuji
3. Detailed Description of the Invention The present invention relates to the extension of the
range of ultrasound focusing in ultrasound probes such as ultrasound diagnostic devices.
Heretofore, as an ultrasonic probe, one having a concaved transducer surface is known as a
structure for focusing ultrasonic waves. FIG. 1 shows the appearance of an ultrasonic beam
generated in the subject with the vibrator in contact with the homogeneous subject. The figure
shows a circular vibrator in which the concave surface is a part of a spherical surface in the
simplest case, as a cross section cut by a plane passing through the center of the spherical
surface and the center of the concave surface. 1 is a vibrator, 2 is an outer edge of ultrasonic
waves emitted from the vibrator, 3 is a central position of a beam-like portion effective when
scanning the vicinity of a target affected part of a subject It is also known that is one of the major
factors that limit the resolution of ultrasound images. Such a concave vibrator generally has poor
contact with the subject, and rarely adheres to the subject as shown in FIG. In order to measure
such adhesion, it has been practiced to fill an adhesive having an acoustic velocity characteristic
equivalent to that of the object between the concave surface of the transducer and the object.
The center position of the beam-like portion in FIG. 1 corresponds to the center position of a
sphere having the concave surface of the concave oscillator as a part of the spherical surface, and
an object such as a contour surface of a tumor near the center point. If there is a tissue
discontinuity, an ultrasound image of the discontinuous interface is obtained by the reflected
wave from this. However, such an image is limited to a good range of resolution or extremely
limited because the range d of the EndPage: 1-group is narrow. Therefore, it is necessary to use a
concave vibration to age a large number of folds as a replacement probe. An object of the present
invention is to obtain an ultrasonic image with high resolution over a wide range by realizing the
enlargement of the range d of the beam portion in the above. The following examples illustrate
the invention. Fig. 2 is a sectional view of an ultrasonic probe according to the present invention,
in which 1 is a concave vibrator, 4 is a filler, 5 is a vibrator holder, and 6 is a vibrator electrode
1)- is there. In the concave-shaped vibrator of the present invention, it is inevitable that filling the
concave portion with a charge has an effect of improving the contact between the vibrator and
the object in the general case, but it is The purpose of the filling in the present invention is the
expansion of the range of the beam-like portion as described above, which will be described with
reference to FIG. The probe of FIG. 3 is an embodiment configured to have good resolution in the
vicinity of the same diagnostic distance as that of the known FIG. 1, and is not particularly shown
in the figure but is a homogeneous target. The sample should be in sufficient contact / this state.
Father, in comparison with the one in FIG. 1, in the present embodiment, the radius of curvature
of the concave surface of the concave oscillator is smaller than that in FIG. 1, and the diagnostic
distance when the filler is not filled is , FIG. 1 (D in FIG. The situation is indicated by the position
of the outer edges 2, 2 'and the beam-like areas d, d' of the emitted ultrasound. Thus, in the state
where the filler 4 is filled, 2.3. In FIG. 3 corresponding to d. It is shown as 37 ', d / 7, and d // is
shown to be sufficiently enlarged with respect to d. Next, the principle of the present invention,
which produces an effect by filling the filler 4, will be described next. FIG. 4 is a drawing for
explaining the principle of the present invention, in which the concave surface of the oscillator l
is formed as a spherical portion with a sphere of radius γ cut off by a plane. The diameter of the
circle that forms the periphery of the concave surface is 2a, the distance between the center 0 of
the concave surface and the center of the above circle (center of the probe surface) P (depth of
the concave surface) is d, p Let f be the distance to the center Q of the sphere. The concave
surface is filled with a filler, and the surface, that is, the probe surface, is made to coincide with
the above-mentioned cut and toe surface. The light is refracted at the interface with the sample
to enter the sample and passes through eight points of straight lines OI) Ql :. The abovementioned refraction follows the known sne and ll law, and the relationship between the angle of
refraction β and the angle of incidence α is determined as the velocity of sound C1 in the filler
and the velocity of sound in the object (this relationship is (sin α / sin β) − It is given as λλCI / C2. When the filler is not filled, the ultrasonic wave from the concave transducer is focused
on the center Q of the sphere and diverges from Q. When the filler is filled, it is focused at points
other than the point Q due to the refraction. Diverge. The point is S, and the distance PS, that is,
the diagnosis distance Z, is given by the following equation. − = Fλ1 + (17,) ′ tan; In this
formula, Z at α−O is X. It becomes 1.2-o-f lambda when it writes (Z at the time of lambda -1).
The fact that the focusing point becomes the Q point at -f has already been described), and x-as
ro = DELTA Z as 1 to lambda, DELTA x = = lambda (A 〒 door) 四-4 -1) Yoshi If λ> 1, then ΔX>
O, and the value of ΔX changes according to the value of d. Since the value of d is in a one-toone correspondence with the positions of two vibration points, the position of the focusing point
S is aligned on X into a straight line OP (a straight m passing through points 0 and P) It becomes.
This 2 2 わ 4 corresponds approximately to d //, and indicates that the focusing point which was
theoretically only at one point when no filler was used was expanded to the focusing line
Analysis of beam width in the range of ΔX obtained by the above expansion +4. The beam
intensity at each point S on Δχ can in principle be determined by integrating the contribution of
all vibration points on the concave surface. In practice, the definition may define an appropriate
value of λ for a given maximum value of d, or an appropriate range of values of λ for a given
value of λ. Although the material EndPage: 2λλ11 is selected, it is convenient to reduce the
density ρ to the extent that を can be equal to dog, in terms of the bioacoustic impedance. For
example, if it is possible to use ρC8-bioacoustic impedance, it is even more advantageous in view
of the problem of reflection at the contact surface between the object and the probe. As apparent
from the above description, according to the present invention, resolution can be increased in a
wider range in the direction of depth of a tomographic image in ultrasonic diagnosis, and a clear
image can be obtained as compared with the conventional one. It becomes possible to get it.
4. Brief description of the drawings. FIG. 1 shows an ultrasonic focusing condition by a
conventional concave vibrator, FIG. 2 is an embodiment of a probe in the present invention, and
FIG. 3 is an ultrasonic wave in the embodiment. Focusing situation is shown, and FIG. 4 is a
principle explanation concerning focusing. ■ Ultrasonic transducer, outer edge of 2 radiation
ultrasonic waves, 3 beam parts, 4 packing materials. Intestinal opening 53-139389 (3) o + figure
'4 EndPage: 3
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