JPH047222B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ultrasonic endoscope apparatus that realizes clear images with little noise.

[Technical Background of the Invention and Problems Therewith] A conventional ultrasonic endoscope device, as shown in FIG. etc., and the signal transmitted by the signal line 2 connected to the vibrator 1 is grounded on one side via brush contacts 3 and 4, and the other side is connected to an external reception display device 5 and a diode 6 for noise cutting. It was led to the transmission pulse generation circuit 7 via.

In an ultrasonic endoscope device using such brush contacts 3 and 4, the received weak waves may be caused by momentary separation of the brush contacts 3 and 4 during rotation or changes in the contact potential difference between the contacts that make up the brush. This has the disadvantage that noise mixes into the ultrasonic signal and appears as noise when displaying a tomographic image, making the tomographic image difficult to see. Furthermore, as disclosed in Japanese Patent Application Laid-open No. 58-41539, there is also a motor in which a motor is housed at the tip and a vibrator is attached to the rotating shaft, but this has the same drawbacks as shown in Fig. 3. .

For this reason, the fourth method to alleviate the above drawbacks is
There is a conventional example as shown in the figure.

That is, the preamplifier 8 is placed on the rotated side shown by the dashed line.
is provided to amplify the ultrasonic signal received by the transducer 1.
Since this amplifier 8 also rotates in synchronization with the rotation of the vibrator 1, a brush contact 9 supplies power, and a brush contact 1 serves to output the output signal of the amplifier 8 to the outside.
0, a brush contact 11 for common signals and a brush contact 12 for applying transmission pulses are required. Note that the noise cutting diode 6 is also provided on the rotating part side. In the ultrasonic endoscope device configured in this way, the received ultrasonic signal is once amplified and then passed through the brush contact 10, so that the noise voltage generated at the brush contact 10 is reduced to the noise at the brush contact 3 in FIG. If the voltage is the same, an improvement in S/N can be expected compared to the configuration shown in FIG. However, since the DC current for the power supply is superimposed on the signal power supply and flows to the brush contact 11 provided on the common signal line, brush noise caused by this DC current becomes a problem, and there is also the drawback that noise appears in the displayed image. .

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and provides an ultrasonic endoscope device capable of displaying clear images with low noise without brush noise being added to received ultrasonic signals. The purpose is to

[Summary of the invention] The present invention amplifies a signal from an ultrasonic transducer that is incorporated into the tip of an endoscope and is rotated and scanned by a preamplifier that rotates in synchronization with the transducer, and the output is amplified by a rotary transformer. By configuring a transmission means in which the power for operating this amplifier is also supplied from the outside through the rotary transformer, generation or mixing of noise due to brushes can be prevented, and an excellent S/N ratio can be achieved. This makes it possible to obtain ultrasonic diagnostic images.

[Embodiments of the Invention] The present invention will be specifically described below with reference to the drawings.

FIG. 1 shows a first embodiment of the invention.

In the ultrasonic endoscope device 21 of the first embodiment, an ultrasonic transducer 23 constituting an ultrasonic transiduer is disposed at the distal end portion 22 of the endoscope, and the ultrasonic transducer 23 is inserted into the insertion section. It is designed to be rotated and scanned by a rotation driving means such as a motor through a flexible shaft 24 (the specific shape is not shown) (formed of a spiral tube or the like).

A cable 25, such as a coaxial cable, whose one end is connected to the vibrator 23 is inserted into the hollow portion of the flexible shaft 24, and the other end of the cable 25 is led to a hand-held operating section. An amplifier unit 26 is provided within this hand-operated unit and is driven to rotate integrally with the flexible shaft 24.

The other end of the cable 25 connected to the vibrator 23 is connected to the input end of a low noise figure preamplifier 27 in the amplifier unit 26.
The output end of the preamplifier 27 is connected to one end of a rotor coil 29a of a rotary transformer 29 via a low-frequency cut capacitor 28 or a bidirectional high-pass filter (not shown). One end of the stator coil 29b of the rotary transformer 29 is connected to a low frequency (for example, several tens to several tens of This oscillation output is applied to the stator coil 29b of the rotary transformer 29 via the high frequency trap 31. Moreover, one end of this stator coil 29b is
For example, it is connected to the reception display device 34 via a high-pass filter 33 formed of a capacitor and a resistor, so that the high frequency signal appearing at both ends of the stator coil 29b can be transmitted to the reception display device 34 side. Note that the other end of this stator coil 29b is grounded.

Rotor coil 2 of the above rotary transformer 29
One end of 9a is connected via a second high-frequency trap 35 to a rectifier/smoothing circuit 36 composed of a diode and a capacitor, and its smoothed output is connected to the power supply terminal of the preamplifier 27.

Further, the output of the transmission pulse generation circuit 37 is connected to the cable 25 via a brush contact 38 and a diode 39.
The common terminal in the amplifier unit 26 is connected to a diode 40 and a brush contact 41.
It is connected to an external common signal line (return of the transmission pulse generation circuit 37) via.

In addition, in FIG. 1, a portion surrounded by a broken line is rotationally driven by a rotational driving means such as a motor.

The operation of one embodiment configured in this manner will be described below.

The high-frequency pulse generated by the transmission pulse generation circuit 37 passes through a brush 38 and a diode 39, and is further transmitted via a cable 25 and applied to a rotationally driven vibrator 23, and the ultrasonic waves excited by this vibrator 23 are targeted. The waves are transmitted to the object side.

Therefore, the ultrasonic wave reflected from the discontinuous boundary surface of the acoustic impedance in the object is transmitted to the transducer 23.
is excited, and the high frequency electric signal generated by the piezoelectric vibration is amplified by the preamplifier 27 via the cable 25. This amplified high frequency signal is applied to the rotor coil 29a of the rotary transformer 29 through the capacitor 28 as shown by the broken arrow. In this case, it is blocked by the high frequency trap 35, so
This high frequency vibration does not flow into the rectifying/smoothing circuit 36 side, and damping etc. are prevented from occurring. Therefore, the high frequency signal applied to the rotor coil 29a by the rotary transformer 29 is transmitted to the stator coil 29 which is inductively coupled to the rotor coil 29a.
b, and is sent to the receiving display device 34 via the high-pass filter 33, where the ultrasonic tomographic image is displayed on the display screen. Furthermore, the high frequency signal transmitted to the stator coil 29b is prevented from flowing into the low frequency sine wave oscillator 32 by the high frequency trap 31.

On the other hand, the low-frequency oscillation output of the oscillator 32 passes through the high-frequency trap 31, passes through the rotary transformer 29 (blocked from reaching the reception display device 34 side by the high-pass filter 33), is transmitted to the rotor coil 29a, and is further transmitted to the rotor coil 29a. After passing through the high frequency trap 35, it becomes a DC smoothed by the rectifier/smoothing circuit 36 and is applied to the power supply terminal of the preamplifier 27.
7 in operational condition. Although the low-frequency signal induced in the rotor coil 29a passes through the rotary transformer 29 in the opposite direction to the high-frequency signal, the capacitor (or high-pass filter) 28 prevents the low-frequency signal from passing and affects the preamplifier 27 side. does not affect In the figure, the flow of high frequency signals (RF) is shown by broken line arrows, and the flow of low frequency signals (AF) is shown by solid line arrows.

Note that the transmitted pulse is transmitted to the brush 38 or the brush 4.
When transmitted through the first class, these brushes 38,
Since the noise voltage generated at 41 is usually lower than the forward voltage of the diode, it is prevented by diodes 39 and 40 and does not affect the received signal.

FIG. 2 shows a second embodiment of the invention.

In this second embodiment, a rotary transformer 53 is used in which a first rotary transformer 51 and a second rotary transformer 52 are provided at two concentric circles at different radii, as is widely used in VTRs and the like. . Therefore, the low frequency oscillator 32 is connected to the stator coil 51b of the first rotary transformer 51, and the rotor coil 51b is connected to the low frequency oscillator 32.
1a is connected to the power supply terminal of the preamplifier 27 via a rectifier/smoothing circuit 36.

Further, the second rotary transformer 52 is connected to the reception display device 34 on the stator coil 25b side, and is connected to the output end of the preamplifier 27 on the rotor coil 52a side. The rest is the same as the first embodiment. In this second embodiment, the rotary transformer 53 is complicated, but one for VTR can also be used. In this case, the frequency of the oscillator 32 is not limited as narrowly as in the first embodiment.
In addition, if a shot ring is interposed between the first and second rotary transformers 51 and 52, more sufficient insulation can be achieved.

Incidentally, as a DC power supply to the amplifier 27, a rotor coil 51a and a stator coil 51 are provided at opposing parts of the first rotary transformer 51 of the second embodiment.
Instead of providing b, a light emitting element (or light emitting means)
It is also possible to provide a photovoltaic force means that generates an electromotive force with light, such as a solar cell.

Incidentally, the transmission pulse can also be configured to be transmitted via a rotary transformer without using a brush contact.

[Effects of the Invention] As described above, according to the present invention, since the signal is transmitted by a rotary transformer without using a brush contact in the path of the received signal, noise caused by the brush contact does not mix into the received signal. Therefore, a tomographic image with good S/N ratio can be obtained.
Furthermore, since the received signal is once amplified and then transmitted by the rotary transformer, the influence of induced noise that is likely to be mixed in when a rotary transformer is used can be reduced. Furthermore, troubles caused by brush noise in the power supply path of the amplifier, which occur when such an amplifier is used, can also be eliminated.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the main parts of the electrical system configuration in the first embodiment of the present invention, and FIG.
A circuit diagram showing the main parts of the electrical system configuration in the embodiment, FIG. 3 is a circuit diagram showing the main parts of the electrical system in the conventional example, and FIG. 4 is a circuit diagram showing the main parts of the electrical system in another conventional example. It is. 21... Ultrasonic endoscope device, 23... Ultrasonic transducer, 24... Flexible shaft, 25... Cable, 26... Amplifier unit, 27... Preamplifier,
28...Capacitor, 29...Rotary transformer,
31, 35...high frequency trap, 32...oscillator, 3
3...High-pass filter, 34...Reception display device, 36...
Rectification/smoothing circuit, 37... Transmission pulse generation circuit, 3
8, 41... Brush contact, 39, 40... Diode, 51... Rotary transformer.

Claims (1)

[Scope of Claims] 1. An ultrasonic transducer that is disposed at the tip of an endoscope, is rotated and scanned by a hollow flexible shaft, and has a signal line guided through the inside of the flexible shaft, and is integrated with the flexible shaft. An amplifier unit is placed in the endoscope's hand control unit, and the signal received by the ultrasonic transducer is input to the amplifier unit, and its rotor coil is connected to the output of the amplifier unit, and its stator coil is connected to the a rotary transformer connected to a reception input terminal of the sonic image display device; an oscillator that applies an alternating current signal with a frequency sufficiently lower than the operating frequency of the ultrasonic transducer to a stator coil of the rotary transformer; and a rotor coil of the rotary transformer. a rectifying/smoothing circuit connected to the AC signal and selectively rectifying the alternating current signal, and using the rotary transformer to constitute a transmission means for supplying power to the amplifier unit and a transmission means for the received signal. An ultrasonic endoscope device featuring: 2. The ultrasonic endoscope apparatus according to claim 1, wherein the ultrasonic transducer is applied with a transmission pulse for ultrasonic emission via a brush contact and a diode.