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BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a principle view of focusing an ultrasonic wave
by an electronic operation, FIG. 2 is a view showing an embodiment of an ultrasonic wave
transmitter according to the present invention, and FIG. FIG. 3 is a diagram showing signals, FIG.
3 is a diagram showing square-law characteristics. G · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·
· · · · · · · · · · · · · · · · · · · · trigger level setter, D ˜ ˜ D · · · · · · · · · · · · · · · · · · · · · · · trigger circuit, C1 ˜ C8
· · · · · · · · · · · · · R4... Resistance, SG... Signal generator, P.
DETAILED DESCRIPTION OF THE INVENTION (1) gif 3 The present invention is a book related to
an ultrasonic transmitter. In the ultrasonic transmitter, various means are taken to improve the
directivity of the transmitted ultrasonic wave, that is, the resolution in the scanning direction. For
example, in an ultrasonic transmitter in which a plurality of ultrasonic transducers (hereinafter
simply referred to as transducers) are linearly arranged, the transmitted ultrasonic waves are one
point by providing an appropriate time delay to the transmission timing of each transducer.
Means are generally used to focus on the FIG. 1 is a principle view of focusing an ultrasonic wave
at one point by an electronic operation. In FIG. 1, A is a pulse generator which outputs a tripaval
that makes ultrasonic waves -A times. Bl-BB is a time delay element, and C1-Cg are transducers
arranged uniformly at equal intervals d as shown in FIG. In such an apparatus shown in FIG. 1,
when the nth oscillator from the center (for example, n = 1 is the oscillators C4 and C5) and IIJ!
As shown in FIG. 1, it is known that ultrasound waves are focused from the array to the position
of focus r. 78 對 V, 1 2 2 · v-r (2) τ: delay time V, speed of sound, but n-d ((in the conventional
device, the play line (delay The timing of the trigger pulse applied to each vibrator was controlled
using a line) or a digital counter. However, the former has a quantization error because it
generates a time delay by using the inductance of a coil having an output terminal at an
appropriate interval, and the latter has a one-pulse error because it is processed digitally. It was
not possible to obtain sharp depth of focus or to freely set the depth of focus. The present
invention provides an ultrasonic transmitter capable of setting the depth of focus in an analog
manner from a signal generator, a comparator, a trigger level setting device and K. FIG. 2 is a
view showing an embodiment of an ultrasonic transmitter according to the present invention. In
FIG. 2, G is a trigger level setter, and the father is a signal generator having a function of
outputting a ramp signal or a 2 (3) -multiplication characteristic signal. P is a clear pulse
generator and outputs a signal to clear the output of the signal generator SG to zero. D □ to D4
are comparators, towns to R4 are resistors, CI-CB is a vibrator, and H1-HB is a trigger circuit that
receives a signal from the comparator DB-D4 and outputs a trigger signal. The trigger level setter
G is, for example, one in which resistors R1, R2, and R3 are connected in series between the
voltage Vcc and the circuit ground.
The voltages e1 to e4 divided by the resistors R1 to are connected to the comparators D1 to D4.
Further, the output of the signal generator 入 力 is input to the comparator DI-D4, and is
compared with each of the voltages e1 to c4 from the above trigger level setting unit G. The
outputs of the comparator D1 are connected to the trigger circuits H4 and H5, the outputs of the
comparator D2 are connected to the trigger circuits H3 and H6, the output of the comparator D3
is connected to the trigger circuits H2 and H1, and the output of the comparator D4 is the trigger
circuit H1. And Hg connected. The trigger circuits H1-Hg are connected to the circuit ground via
the transducers Cl-C5, respectively. The output signal of the clear pulse generator P is applied to
the signal generator. (4) The operation of the apparatus in FIG. 2 configured and connected in
this way is as follows. For example, the case where the ramp signal shown in FIG. 3 (a) is used as
a signal generator will be described. The vertical axis of (A) shows the voltage level, and the
horizontal axis shows the time axis. The signal generator SG can be easily configured by, for
example, an integrator and a reference voltage generator. At time TI, the output between the
signal generators gradually increases as shown in the operation line (1) of FIG. 5 (to). After time
21, when the output of the signal generator SG becomes the voltage @ 1, the comparator D4
operates, and as a result, a rapid voltage change is applied to the transducers C1 and C8 via the
trigger circuits H1 and H8, and an ultrasonic wave is emitted. Be done. Further, when the ramp
signal voltage increases and becomes the voltage e2 after time 72, the comparator D3 operates
and a rapid voltage change is applied to the transducers CI and C7 via the trigger circuits H2 and
H7, and an ultrasonic wave is emitted at that time . Thus, every time the ramp signal reaches the
voltage e □ -C4 set by each of the comparators Dl-D4, a rapid voltage change is added to the
vibrator C1-cB from the comparator via the trigger circuit H1-HB to bτ1-74. Ultrasonic waves
are transmitted one after another with a delay time of. (1) 5) The delay time is determined by
determining the inclination of the ramp deviation of the signal generator SG and the voltages e □
to e4 obtained by the trigger level setting unit G in advance so as to obtain the time τ indicated
by 5) It can be in film and focus on the desired depth of focus. That is, in this case, the
relationship of the magnitude 142 of the voltage e1je2 °... C4 to the power of 7 ++ 3 .fwdarw.7
characters in order is shown in FIG. 5 (b) as a signal generator SG. As in the case of using a signal
generator having a square characteristic in which the output increases with time as time goes by,
the magnitudes of the voltages el and [email protected] may be in a proportional relationship.
Although only eight vibrators are displayed in the apparatus of FIG. 2, in an actual apparatus,
more vibrators are provided in a line, for example, the vibrators c1-cB, (2-Cg, C3-CIO. Ultrasonic
waves are emitted one after another in combination of. In the apparatus shown in FIG. 2,
although the ultrasonic waves are assembled and the number of transducers driven by ultrasonic
wave transmission is eight, this description does not limit the number of vibrators. . Thus,
according to the present invention, the analog adjustment of the depth of focus, which was
difficult with the conventional ultrasonic transmitter (6), can be achieved by appropriately
combining the voltage of the trigger level setter and the signal of the signal generator. The depth
of focus can be determined for the customer layer, and as a result, it is possible to obtain 7
depths of focus δ and the effect is extremely significant.