JPH04292133A - Electronic endoscope device - Google Patents

Abstract

PURPOSE:To prevent the flow of an overcurrent by the trouble, etc., of circuit constituting members to be placed in a patient circuit and to assure higher safety by decreasing these circuit constituting members as far as possible at the time of dividing the processor of the electronic endoscope device to the patient circuit and a secondary circuit and insulating these circuits from each other by an isolation means. CONSTITUTION:This electronic endoscope is so constituted as to pass the video signal from an image pickup means 5 transmitted via a coaxial cable 6 into the processor 20 through an emitter-follower circuit 22, then to pass the signal through the isolation element 40, by which the circuit constituting members provided in the patient circuit PC are decreased to the emitter follower circuit 22 alone. The higher safety is thus assured and the deterioration of the video signals is obviated.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to an electronic endoscope device used for medical purposes, and more particularly to an electronic endoscope device in which a processor is divided into a patient circuit and a secondary circuit, and the circuit is insulated between them by an isolation means. This invention relates to a viewing device.

0002

2. Description of the Related Art In general, an electronic endoscope apparatus is provided with an imaging means such as a CCD at the distal end of an insertion section constituting the endoscope body, and this imaging means photoelectrically converts an image of a subject inside the body. This video signal is transmitted to a processor and subjected to predetermined signal processing, and the image of the subject is displayed on a display based on this video signal. Since various devices are increasingly being connected to this processor, it is necessary to ensure safety by, for example, protecting the patient's body from excessive current flow. For this purpose, the processor is divided into a patient circuit and a secondary circuit, and a so-called isolation means consisting of a photocoupler, a transformer, etc. is interposed between the patient circuit and the secondary circuit, and electrical connection is established between the two circuits. Increasingly, devices are being used that are constructed so that signals are sent and received in an insulated state, thereby preventing excessive current from flowing to the patient circuit side.

0003

[Problems to be Solved by the Invention] When separating the patient circuit and the secondary circuit using isolation means, from the standpoint of ensuring safety, it is important to place the various circuit components constituting the processor on the secondary circuit side as much as possible. need to be placed. The more circuit components are provided on the patient circuit side, the higher the failure rate and the greater the risk that excessive current will flow into the patient's body.

The present invention has been made in view of the above points, and its object is to provide an electronic endoscope device that can more reliably protect patient safety through isolation means. This is the purpose.

[0005]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a video signal transmitted from an imaging means via a coaxial cable, and a signal at the receiving end of the coaxial cable via an emitter follower circuit. , is characterized in that an isolation element is provided on the output side, and the components of the video signal processing circuit other than the emitter follower are provided on the secondary circuit side.

[0006]

[Operation] There are two types of signal flows in the processor.
One of them is an imaging means and a system for processing video signals,
That is, one is a video signal processing system, and the other is a system that supplies drive signals and control signals to the imaging means and other circuit components, that is, a control signal supply system. Among these, since the control signal supply system must supply a drive signal to the imaging means, at least the imaging means driving circuit must be provided on the patient circuit side. On the other hand, since the circuit members constituting the video signal processing system usually transmit signals from the imaging means to the processor via a coaxial cable, an emitter follower circuit is provided in order to adjust the impedance thereof. The output signal from this emitter follower circuit is waveform-shaped by a low-pass filter, and then sent to a video signal processing circuit.
Signal processing such as clamping, blanking processing, and gamma correction is performed.

[0007] Here, a video signal transmitted via a coaxial cable is sent to both ends of a resistor that is short-circuited by a matching resistor. After this signal is once subjected to impedance conversion via an emitter follower circuit, an isolation element is provided, and all other circuit components of the video signal processing system are provided on the secondary circuit side. This further improves safety. As this isolation means, by using isolation elements such as photocouplers and pulse transformers with wide band characteristics,
A modulation circuit is provided in front of this isolation element,
There is no need to perform signal modulation and provide a demodulation circuit after the isolation element. As a result, the number of constituent members of the patient circuit can be further reduced, safety can be further improved, and the circuit configuration can also be simplified.

When looking at the passing frequency characteristics of isolation elements, there are some that approximate the frequency characteristics of a low-pass filter for shaping the waveform of a video signal. Therefore, by selecting and using an isolation element that has the same frequency characteristics as the low-pass filter, the isolation element can also be used as a low-pass filter, which further simplifies the circuit configuration of the processor. be able to.

Note that it is necessary to provide isolation means in the control signal supply system, but in this control signal supply system, only the imaging means drive circuit is provided in the patient circuit, and the reference frequency signal from the reference frequency generation circuit is The pulse signal may be transmitted to the imaging means driving circuit via this isolation means, and the pulse signal necessary for driving the imaging means may be generated in this imaging means driving circuit. In this control signal supply system, the frequency band is extremely narrow, so if you select and use elements that can transmit the reference frequency signal as the isolation means, it is possible to perform video signal processing. Similar to the system, there is no need to provide modulation and demodulation circuits.

0010

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows the overall system configuration of the electronic endoscope device. In the figure, reference numeral 1 indicates the insertion part of the endoscope body into the body, and a light guide 2 made of an optical fiber bundle is inserted into the insertion part 1, and its output end 2a is inserted into the insertion part 1.
faces an illumination lens 3 attached to an illumination window formed at the tip of the insertion section 1, and the illumination light sent through the light guide 2 is directed from this illumination lens 3 toward the subject. It has become. Further, an objective lens 4 is provided at the distal end of the insertion section 1, and an imaging means 5 made of a solid-state imaging device such as a CCD is arranged at the imaging position of the objective lens 4.

Next, 10 indicates a light source device, and 20 indicates a processor, and these light source device 10 and processor 2
0 is provided as an integrated or separate device, and as is well known, the universal cord of the endoscope body is connected to it, illumination light is supplied from the light source device 10, and the endoscope body and the processor 20 are connected to each other. Signals are exchanged between them. The light source device 10 has a light source lamp 11, and between the light source lamp 11 and the entrance end 2b of the light guide 2, an aperture 12, a condenser lens 13, and a rotating color filter 14 are arranged in order from the light source lamp 11 side. It is arranged. As a result, R, G, and B illumination is sequentially irradiated toward the subject via the light guide 2.

As the processor 20, first, the imaging means 5
Imaging means drive circuit 2 for supplying drive signals to
1 is provided, and the signal charge accumulated in the imaging means 5 is read out based on the drive signal from the imaging means driving circuit 21. The signal read out from the imaging means 5 is transmitted via the coaxial cable 6 to the emitter follower circuit 22, where the impedance is adjusted, and then the waveform is corrected by the low-pass filter 23. It is sent to the video signal processing circuit 24,
After performing signal processing such as clamping, blanking processing, and gamma correction, the signal is converted into a digital signal by the A/D converter 25, and the field image data of each color of R, G, and B is stored in the field memory 26. It is now possible to do so. The image data stored in the field memory 26 in this way is simultaneously read out, converted into analog signals by the D/A converters 27R, 27G, and 27B, and then sent to the amplifiers 28R, 28G, and 28B.
A video signal output is obtained by amplifying the signal.

Here, it is necessary to apply clock pulses and horizontal and vertical synchronization signals to the video signal processing circuit 24, field memory 26, etc. For this purpose, a main synchronization signal generation circuit 30 is provided, and a pulse generation circuit 31 generates necessary pulses based on the reference frequency signal generated by the main synchronization signal generation circuit 30, thereby controlling the required circuits. We are trying to supply it. Further, a similar pulse is applied to the imaging means drive circuit 21 as well.

As described above, the processor 20 has two signal transmission systems: a video signal processing system and a pulse signal transmission system. Therefore, when separating the patient circuit PC and the secondary circuit SC and electrically insulating them, the video signal processing system and the pulse signal transmission system are considered separately and isolation means is provided. Moreover, in order to further improve safety, the patient circuit P
Reduce the number of circuit components on the C side as much as possible.

First, in the video signal processing system, the output signal of the imaging means 5 passes through an emitter follower circuit (not shown) provided immediately after its output terminal, and then the video signal is transmitted to the processor 20 via the coaxial cable 6. do. This video signal is matched with the characteristic impedance of the coaxial cable 6 and then passed through the emitter follower circuit 22. An isolation element 40 is provided on the output side of the emitter follower circuit 22 to separate the patient circuit PC and the secondary circuit SC at this position. Moreover, as the isolation element 40, an element is used that can transmit a wide band signal up to about 6 MHz without deterioration. Thereby, high band noise etc. in the signal transmitted from the patient circuit PC side to the secondary circuit SC side can be prevented by the isolation element 40. As a result, the video signal can be transmitted without deterioration, and among the circuit components that make up the video signal processing system, only the emitter follower circuit 22 is disposed on the patient circuit PC side, and all other circuit components are disposed on the patient circuit PC side. Secondary circuit S for circuit components
Since it can be provided on the C side, safety is further improved.

On the other hand, in the pulse signal transmission system, the main synchronizing signal generating circuit 30 is provided on the side of the secondary circuit SC, and the synchronizing signal necessary for the field memory 26 etc. is generated from the main synchronizing signal generating circuit 30. A pulse generation circuit 31 is connected to this main synchronization signal generation circuit 30 in order to supply the video signal processing circuit 2 through this pulse generation circuit 31.
3 and the field memory 26. Further, the reference frequency signal from the main synchronization signal generation circuit 30 is transmitted to the patient circuit PC side via the isolation element 41, and the imaging means drive circuit 2 provided on the patient circuit PC side.
1, and the imaging means driving circuit 21 generates a synchronizing signal necessary for driving the imaging means 5 and applies it to the imaging means 5. This allows the processor 20
A synchronizing signal is supplied to each circuit constituting the processor 20 based on a common reference frequency signal, so that the entire processor 20 and the signals between the processor 20 and the imaging means 5 can be synchronized.

With the above configuration, the patient circuit PC and the secondary circuit SC are separated by the isolation means.
When separated, in the video signal processing system, only the emitter follower circuit 22 is arranged on the patient circuit PC side, and in the pulse signal transmission system, only the imaging means driving circuit 21 is arranged in the patient circuit PC. Therefore, the number of circuit components installed on the patient circuit side is kept to a minimum.
It is possible to minimize the risk of excessive current flowing to the patient due to a failure of a circuit component constituting the processor 20, thereby further improving safety. Moreover, since a broadband isolation element 40 is used in the video signal processing system, there is no need to modulate and demodulate signals before and after the isolation element 40, simplifying the circuit configuration. It turns out.

By the way, some isolation elements have the same frequency characteristics as the transmission frequency characteristics of a low-pass filter used in this video signal processing system. Therefore, as shown in FIG. 2, if an isolation element 40' having such frequency characteristics is used, there is no need to provide a separate low-pass filter after the isolation element 40', so that the circuit of the processor 20' can be improved. The configuration can be further simplified.

[0019]

Effects of the Invention As explained above, the present invention provides a patient circuit with only an emitter follower circuit among the various circuit components constituting a processor and a circuit constituting a video signal processing system. Since the circuit component is arranged to be provided on the secondary circuit side, it is possible to process the video signal without deteriorating it, and further improve safety.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a circuit configuration of an electronic endoscope device showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a circuit configuration of an electronic endoscope device showing a second embodiment of the present invention.

[Explanation of symbols]

5 Imaging means 20, 20' processor 21 Imaging means drive circuit 22 Emitter follower circuit 23 Low pass filter 24 Video signal processing circuit

Claims (2)

[Claims] Claim 1: An endoscope body equipped with an imaging means for photoelectrically converting a subject image at the distal end of the insertion section, a processor for processing a video signal from the imaging means, and an endoscope based on the video signal processed by the processor. an electronic endoscope having a display for displaying an image of a subject, and having a structure in which circuit components constituting the processor are divided into a patient circuit and a secondary circuit, and the circuit is insulated between them by an isolation means. In the apparatus, a video signal transmitted from the image pickup means via a coaxial cable is transmitted through an emitter follower circuit, and an isolation element is provided on the output side of the signal from the receiving end of the coaxial cable. An electronic endoscope device characterized in that a component of a signal processing circuit is provided on a secondary circuit side. 2. The electronic endoscope apparatus according to claim 1, wherein the isolation element is configured to have a low-pass filter function.