JPS6055923A - Noise preventing device of electronic scope - 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] [Technical Field of the Invention] The present invention provides a scope (herein, scope refers to an endoscope, hereinafter referred to as an endoscope) equipped with a solid-state imaging device on the distal end side of the insertion section in combination with, for example, a high-frequency incision and resection tool. The present invention relates to a noise prevention device for an electronic scope that prevents high-frequency noise from a high-frequency cutting and cutting tool from being superimposed on a wedding image captured by a solid-state image sensor.

[Technical background of the invention]

Conventionally, medical scopes have two types: a rigid scope with a rigid, almost linear insertion section, and a flexible scope with a flexible insertion section that can be inserted into the patient's body through the oral cavity. It has an imaging optical system composed of an objective lens and the like that observes and images the inside of the subject. This imaging optical system transmits the formed internal image to the end surface of the image guide on the hand operation unit side through the channel of the optical fiber bundle that overlaps the image guide, so that the internal image of the subject can be observed through the eyepiece. There is. Further, the illumination light from the light source device is irradiated onto the subject from the hand-held operating section through a light guide cable also made of an optical fiber bundle. In addition, the scope insertion section has a channel for guiding treatment tools such as forceps and interfrequency scalpels from the hand control section to the tip of the insertion section, allowing you to perform treatment under the observation of the endoscope. Tests can now be taken.

[Problems with background technology]

By the way, with recent advances in electronics, COD (charge coupled device) and BBD (Bac
Solid-state imaging devices such as a 13rigade device) and an MO8 type sensor have been developed, and these solid-state imaging devices have come to be used at the tip of the insertion section of a scope.

However, when performing high-frequency ablation surgery, biopsy collection, etc. on a subject using a high-frequency incision and resection tool (hereinafter referred to as high-frequency scalpel) using an electronic scope that uses such a solid-state image sensor, high-frequency radiation from the cauterization power source of the high-frequency scalpel There is a problem in that the current becomes noise and is superimposed on the wedding picture signal read out by the scanning of the solid-state image sensor, making the image displayed on the image display device unclear. In order to make this problem more concrete, it will be explained using FIG. 1.

In FIG. 1, reference numeral 1 indicates the distal end side of the insertion section of the electronic scope, and this distal end side of the insertion section is continuous with the hand operation section 2. As shown in FIG. This hand operation section 2Fi has an eyepiece section 4 having a liquid crystal panel 3.
are connected or integrally formed. In addition, the hand operation section 2 has a treatment instrument insertion section 5 on the upper side, and a light guide cable 6 and a signal line 8 to the image processing circuit 7 on the lower side.
A W guide portion 9 such as the above is formed. Note that the image processing circuit 7
is connected to, for example, a cathode ray tube display device CRT, and the signal line 8
This circuit performs processing for displaying the internal celebration image signal on the cathode + W tube display device CRT as an endoscopic image, and generates a power supply voltage to a preamplifier unit, etc., which will be described later.

The output of the image processing circuit 7 is also supplied to the liquid crystal panel 3, and the same endoscopic image as that of the cathode ray tube display device CRT is displayed at the eyepiece section 4.
It can be observed from

On the other hand, on the distal end side of the insertion portion, a signal channel 10 through which the signal line 8 to the image display device CRT is inserted, a treatment instrument channel 11, and a light guide channel (not shown) for the light guide cable 6 are provided. In the signal channel 10, an objective lens 12 is fully fitted into the distal end surface of the insertion portion, and behind the objective lens 12, a solid-state image sensor 13 made of, for example, COD is disposed. This solid-state image sensor 13 is divided into, for example, a photoelectric conversion section 13a and an accumulation/readout section 13b, and the internal image received by the photoelectric conversion section 13a from the objective lens 12 is converted into an optical signal charge and sent to the accumulation/readout section 13b. The data is stored and sequentially read out for each horizontal line, and the output is delivered to the wound amplifying section 14 at the subsequent stage.

The preamplifier 14 amplifies the signal read out from the storage/reader 13b and outputs it to the signal line 8 as a congratulatory image signal.

Further, a high-frequency scalpel 15 is inserted into the electronic scope through the treatment instrument insertion section 5. This - frequency wave scalpel 1
5 consists of a proximal side 16, a high frequency transmission line 17, and a female part 18 forming an integral loop with the high frequency transmission line 17.The high frequency transmission line 17 is covered with a flexible sheath 19.

When loading the high-frequency scalpel 15 into the electronic scope, the tip of the sheath 19 is inserted from the treatment instrument insertion section 5 and introduced into the treatment instrument channel 11 at the insertion section tip 1 through a passage in the hand operation section 2 (not shown). As the insertion progresses, the tip of the sheath 19 of the high-frequency scalpel 15 protrudes from the tip surface of the insertion portion. From the distal end surface of this sheath 19, the female part 18
is prominent. This sheath 19 has a locking ring 21 formed inside its tip, and an annular slider 20 that is movable within the sheath 19 is provided behind the locking ring 21. The high frequency transmission line 17 is connected to the slider 20 and the locking ring 21.
The tip of the loop-shaped female part 18 is inserted into the locking ring 21.
1C is fixed. With this configuration, the slider 20
can be moved within the sheath 19 by moving the knob 22 on the proximal side 16 of the high-frequency scalpel 15, and the slider 20
When the female part 1 hits the stopper 21 and stops, the female part 1
The loop No. 8 is the largest and the affected part of the subject is hung in the loop, and by pulling the knob 22, the slider 20 is moved back and the loop is made smaller so that the affected part can be held between the loops.

Roughly speaking, the high-frequency scalpel 15 is supplied with a high-frequency current from a cautery power source 25 consisting of a high-frequency ignition power source 23, a power amplifying section 24, etc. to the proximal side 16 via an external high-frequency transmission line 25a, and is connected to the endoscope. The high frequency current is made to flow out to an island frequency transmission line 17 (hereinafter referred to as internal high frequency transmission line). This high frequency current circulates to the ground line of the cautery power source 25 via the subject and a grounding plate (not shown) attached to the subject.

According to such a configuration, biopsy sampling using the high-frequency scalpel 15, surgery for extracting the affected area, etc. can be performed while observing through the scope and displaying the congratulatory image on the cathode ray tube display device CRT.

Therefore, the frequency of the high-frequency current of the ablation power source 25 is set to a value that has the greatest effect on the subject (human body). It is generally considered appropriate for this frequency to be 300 (KEIZ) or higher. On the other hand, if the family celebration image signal is a color signal, it has a frequency band of, for example, 4.3 [■taku]. Figure 2 shows the frequency spectrum N and cylinder circumference of this color endoscopic image signal.
It is a waveform diagram showing the frequency spectrum H of % flow, where the vertical axis represents the spectrum intensity and the horizontal axis represents the frequency. Spectrum of high frequency current Hi For example, center frequency (
The oscillation center frequency of the high frequency signal source 23) is 0.5 (MH
z) is set. The spectrum H of this high frequency current
The reason why the spectrum does not form a single spectrum and spreads vertically in a band shape is due to distortion of the power amplifier 24 or the fact that the signal itself from the high frequency signal source 23 contains components other than the fundamental wave.

If the band of the wedding image signal and the band of the high-frequency current of the high-frequency scalpel 15 overlap in this way, the high-frequency scalpel 15
Due to the electromagnetic conduction between the internal and external high frequency transmission lines 17, 25a and the signal line 8, the high frequency current of the high frequency scalpel 15 is superimposed as noise on the wedding image signal flowing through the signal line 8, and is displayed on the cathode ray tube display device CRT. The image of the wedding ceremony given to the patient was unclear, and in severe cases, the surgery had to be canceled.

As a countermeasure to this problem, conventionally, as in Japanese Patent Publication No. 58-69530 and Japanese Patent Publication No. 58-69528, the part where the high frequency current flows is shielded, and the band of the high frequency current is raised to avoid the band of the family celebration image signal. In addition, methods have been proposed in which the band of the family congratulatory image signal is raised to avoid the high frequency current band. It wasn't something I was trying to remove.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and when a high-frequency current that drives a high-frequency scalpel is unexpectedly superimposed on an endoscopic image signal and becomes noise, it is possible to actively remove this and operate the endoscope. An object of the present invention is to provide a noise prevention device for an electronic scope capable of displaying a faithful and clear image of a family celebration on an image display device of an electronic scope.

[Summary of the invention]

The present invention provides a front-stage amplifier for extracting the wedding image signal obtained by the solid-state image sensor in a differential output format, and outputs each output of the front-stage amplifier to the rear-stage amplifier (differentially). By utilizing the fact that the noise from the high-frequency scalpel is superimposed on each output of the front-stage amplifier as common-mode noise, the rear-stage amplifier cancels and removes the common-mode noise.

[Embodiments of the invention]

The present invention will be explained in detail below. Here, FIG. 3 is a circuit diagram showing a noise removal device for an electronic scope according to an embodiment of the present invention, and FIG. 4 is an operation waveform diagram explaining the operation of FIG. 3), and FIG. FIG. 6 is a diagram showing a specific example when used in combination with a high-frequency scalpel.

First, FIG. 3 will be explained. FIG. 3 shows an imaging system inside the electronic scope, and the same components as those in FIG. 1 are denoted by the same reference numerals. The solid-state image sensor 13 is composed of, for example, a CCD, and stores and stores light signals received by the photoelectric converter L3a.
The data is temporarily stored in the readout section 13b, read out for each horizontal line, and delivered to the conducting wire 26 as a family celebration image signal.

This conducting wire 26 is connected to the preamplifier section 14 shown by a dashed line.

As shown in the figure, this preamplifier section 14 includes, for example, an amplification stage composed of a low-noise differential amplifier 27 and a differential amplifier 27.
It is composed of an impedance converter zs, 29 that matches the output resistance of each differential output terminal. The endoscopic image signal from the solid-state imaging device 13 is applied to the inverting input terminal of the differential amplifier 27.
The non-inverting input terminal of is connected to ground. In addition, each of the impedance converters 28 and 29 is connected to the differential output terminals T1 and T2 of the differential amplifier 27, and the output side is connected to each end of the double-wire shielded cable 3o. This double, two-wire shielded cable 3o has core conductors 30a, 30a conductors 30b, and the internal cables are connected to an inverting input terminal and a non-inverting input terminal of a twisted winding 31, respectively.This differential amplifier 31 The output section uses one of its differential output terminals and is connected to the output terminal 32.The endoscopic l1iJ image signal derived to the output terminal 32 is sent to the image processing circuit 7 in FIG. It is now being supplied.

According to the electronic scope having the above configuration, the congratulatory image signal received by the solid-state image sensor by scanning is preamplified by the differential amplifier 21 in the previous stage. For example, the waveform S shown in FIG. 4 is applied to the output terminal Ill.
A negative polarity congratulatory image signal such as 1 is obtained, and a positive polarity congratulatory image signal such as waveform S2 in FIG. 4 is obtained from the other differential output terminal T2VC. Regarding these endoscopic image signals,
The period tr indicates a synchronization signal period, and the period ts indicates an image signal period. And the waveform S1 is the impedance converter 2
The waveform S2 passes through the impedance converter 29 and is output as it is to one core wire 30a of the two-wire shielded cable 30.
The other core 113UaK4 of the wire shield cable 30 is taken out. The waveforms St, 82 derived from these cores i30a, 30a are differentially input to the inverting and non-inverting input terminals 31 of the differential amplifier 31. Here, as a characteristic of the differential amplifier 31, its differential gain is large and its common mode gain is extremely small, so when the differential gain is set to 1,
The signal waveforms of different polarities during the image period TII are differentially amplified and outputted to the output terminal 32 as an endoscopic image signal with double the amplitude as shown in waveform S3 in FIG.

Now, the operation when external noise is induced by a high frequency scalpel or the like in the path after the differential output terminals TI and T2 of the differential amplifier a in the previous stage will be explained.

Such external noise is superimposed as noise having the same phase as the waveform Sl, 52iC. That is, in FIG. 4, the waveform S1
For example, the bipolar noise waveform N A I N n and the in-phase noise waveforms NA' and NB' are superimposed on the signal.

Here, NA indicates negative polarity noise, and NB indicates positive polarity noise. Then, the noise waveform NA on which the waveform SIK is superimposed.

NB is in phase with the noise waveforms NA' and NB' superimposed on the waveform S2, and is differentially input to the differential amplifier 31 at the subsequent stage through the double 2-wire shielded cable 30.

The differential amplifier 31 at the subsequent stage amplifies the differential component with reversed conduction polarity, but does not amplify the in-phase component with the same polarity, so the noise waveforms NA, NB and the noise waveform NA/
, N B / are not amplified. In other words, since the differential input level between the noise waveforms NA, NB and the noise waveforms NA', 1tJB' is zero, only the waveform St+82 based on the original wedding image signal is amplified. Therefore, the original signal waveform (portion shown by the dotted line) buried by the noise waveforms NA, NB, NA', NB' is restored, and the waveform S3 can include the noise waveforms NA, NB, NA', NB'. do not have.

In this way, the present invention can display a faithful and clear image of the family celebration on the image display device 7 (including the liquid crystal spring 3) on the electronic scope operating section side. Moreover, the signal component is approximately 2
Since the signal is doubled and the noise component is removed, the signal-to-noise ratio becomes very good.

FIG. 5 specifically shows the above embodiment. In FIG. 5, the same parts as in FIGS. 1 and 3 are designated by the same reference numerals. The electronic scope has an insertion guide cable 6 and a lead-out portion 9 for a signal line 8 to an image processing circuit 7 and the like. On the other hand, the high-frequency scalpel 15 is inserted through the treatment instrument insertion section 5, passes through the treatment instrument channel U (il-), and passes through the sheath 19 from the end surface of the insertion section tip 111111 of the electronic scope.
The distal end portion and the female portion 18 protrude.

Further, in the high-frequency scalpel 15, a high-frequency current supplied from a cautery power source 25 is externally transmitted to a proximal side 16 via a high-frequency transmission line 25a VC, and an external high-frequency transmission line 25a and an internal high-frequency transmission line 17 are connected to the proximal side 16. Thus, a high frequency temporary current can be supplied to the female part 18. Further, the loop diameter of this female portion 18 can be expanded or contracted by operating a knob 22 on the proximal side 16.

Next, on the distal end side 1 of the insertion section of the electronic scope, there are the treatment channel 11, the signal channel 10, the kite guide channel (shown in the figure) of the light guide cable 6, etc., and the end opening of the signal channel 10 has an objective lens 12. is located. A solid-state image pickup device 13 is housed behind the objective lens, and a final image captured by the solid-state image pickup device 13 is input to a preamplifier 14 as a private image signal. The preamplifier 14 is electrically shielded from the outside by a grounding member 14a. Further, the preamplifier section 14 is provided with a differential amplifier 27 as an amplifying element. One of the differential output terminals of the differential amplifier 27 is connected via an impedance converter 28 to one core wire 30aKm of a signal line 8 constituted by a double two-wire shielded cable.

The other differential output terminal of the differential amplifier 27 is connected to the other core wire 30 of the signal line 8 via an impedance converter 29.
It is connected to a. These cores 47130a, 3
0a is covered by an intermediate conductor 30b. Furthermore, this intermediate conductor 30b is covered with an outer conductor 30C and functions as a 212m shielded cable. Note that the external conductor 30C is connected to the image processing circuit 7, for example.
The intermediate conductor 30b is grounded by the grounding member 14a of the preamplifier 14 and the grounding member 7a of the image processing circuit 7. Furthermore, core wire 3Qa
, 30a are connected to respective differential input terminals of a differential amplifier 31 provided in the preceding stage of the image processing circuit 7. Then, the image signal processed by the image processing circuit 7 and obtained is output to the video amplification stage of the cathode ray tube display device CRT and the liquid crystal panel 3 of the eyepiece 4, so that it can be displayed as an endoscopic image. There is.

According to the electronic scope described above, when the high-frequency scalpel 15 is driven, the core wire 30 a of the signal line 8 is caused by magnetic lines of force formed by high-frequency currents flowing through the external high-frequency transmission line 25 a and the internal high-frequency transmission line 17 . , 30a as noise can be suppressed by the effect of the double two-wire shielded cable. If it is induced unexpectedly, the differential amplifier 27 and the image processing circuit 7 in the previous M amplification stage
Noise can be attenuated by the above-described common mode component removal action with the differential amplifier 31 on the side.

Next, another embodiment of the invention will be described with reference to FIG. 6. In FIG. 6, the same parts as in FIG. 3 are denoted by the same reference numerals.

In this embodiment, the output format of the differential amplifier 27 that receives the endoscopic image signal of the solid-state image sensor 13 is a single output format, and the output terminal T3 is connected to one core wire of the double double-wire shielded cable 30 as the signal line 8. 30a, while the other core wire 30a is grounded via a resistor R1. The resistance value of this resistor R1 is the output resistance R of the differential amplifier 27.
It is set equal to the resistance value of O. Therefore, there is no need to provide impedance converters 28 and 29 as in the case of FIG. 3, and the configuration can be simplified. The other ends of the 2N 2-wire shielded cables 30 are connected to the differential amplifiers 31 in the subsequent stage, respectively, and the family congratulation image signals are derived to the output terminals 32.

According to the above configuration, although multi-signal components are not amplified as in the case of the above embodiment, noise components can be reliably removed.

The gist of the present invention is to remove noise by using, for example, a differential amplifier 27 as a front-stage amplifier and a differential amplifier 31 as a rear-stage amplifier, and the signal line 8 is not limited to the double two-wire shielded cable 30. A pair of unshielded single wires may be used, or t7'c, z shielded cables may be used.

Further, the external noise is not limited to that caused by the high frequency scalpel 15, but also noise from other medical instruments that use high frequency, fluorescent lights, automobile spark plugs, etc. can be removed.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to reliably remove extraneous noise superimposed on the wedding image signal obtained by the solid-state image sensor of the electronic scope, and the image display device on the electronic scope operating section is always displayed clearly. This makes it possible to display images that are unique.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a conventional configuration using an electronic scope and a high-frequency incision/excision tool, Fig. 2 is a waveform diagram showing a spectral structure of a wedding image signal and a high-frequency wave upstream, and Fig. 3 is a diagram showing an embodiment of the present invention. 4 is a waveform diagram illustrating the operation of an embodiment of the present invention; FIG. 5 is a diagram illustrating a specific embodiment using the embodiment of the present invention; FIG. The figure is a circuit diagram showing a noise removal device according to another embodiment of the present invention. l...Distal end side of the insertion tube, 2...Hand control unit, 7...Image processing circuit, 8...Signal line (30...・Double double wire shielded cable), 1
3...Solid-state image sensor, 14...Preamplifier, 27, 31...Differential amplifier, 28.2
9... Impedance converter, CRT...
...Cathode ray tube display device. Procedural amendment (spontaneous) Ua Japanese Patent Application No. 163598 26 Name of the invention Noise prevention device for electronic scope 7.7+li Correct content As shown in Attachment 1, page 17 of the specification, lines 19 to 20 In the second paragraph, the phrase ``receive... as a formula'' is corrected to ``amplify with the preamplifier 33.'' 2. In the 3rd line of page 18 of the memorandum, the words ``differential amplification'' are corrected to ``preamplification.'' 3. In the 5th to 7th lines of page 18 of the specification, change the statement ``Impedance...'' [Since a differential amplifier is not used in the preamplifier 33, the amplifier configuration is simplified. , the noise figure is also improved by 3clB. ” he corrected. 4. Add [33...Preamplifier] to the 4th line of page 20 of the specification. that's all

Claims (1)

[Scope of Claims] (1) In an electronic scope that uses a solid-state imaging device on the distal end side of the insertion section and displays a family celebration image signal obtained by the solid-state imaging device as a family celebration image on an image display device, the endoscopic image signal 1. A noise prevention device for an electronic scope, characterized in that a noise eliminating means is provided for eliminating external noise induced by a signal path VC leading to an image display device. <2) The noise removal means includes a pre-stage amplifier provided on the solid-state imaging device side, which amplifies and differentially outputs a congratulatory image signal from the solid-state imaging device, and a pre-stage amplifier provided on the image display device side. and a post-stage amplifier which differentially inputs each output of the pre-stage amplifier, and the external noise superimposed on the differential output of the pre-stage amplifier as a common mode component is attenuated by the post-stage amplifier. A noise prevention device for an electronic scope according to Scope 1. (3) The noise removing means is characterized in that the two conductive wires serving as the signal path connecting the differential output terminal of the front-stage amplifier and the differential input terminal of the rear-stage amplifier are shielded. A noise prevention device for an electronic scope according to claims 1 and 2.