JP2020014658A - Endoscope device - Google Patents

Abstract

To improve safety of an endoscope device.SOLUTION: An endoscope device is used by fitting a first metal connection part 18 comprised in an endoscope scope 1 and a second metal connection part 19 comprised in an endoscope processor 2 and connecting a plurality of signal lines. The second metal connection part 19 is grounded via an electrostatic induction circuit 20 comprising a capacitor C and a current suppression resistor Rr mutually connected in series, and a discharging resistor Rd connected in parallel with the capacitor C and the current suppression resistor Rr.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to an endoscope device.

  2. Description of the Related Art Conventionally, an endoscope apparatus has been used to capture an image of an intestinal wall or the like in a body. The endoscope apparatus includes an endoscope having an operation unit for operating a flexible tube inside the body, a light source for irradiating light from the end of the endoscope scope, and reception from the endoscope scope. And an endoscope processor having a processor or the like for processing the processed image, and both are connected to each other for use. An image captured by the endoscope is, for example, converted into an electric signal, transmitted to an endoscope processor via a communication cable, and displayed on a monitor connected to the endoscope processor.

  The connection between the endoscope and the endoscope processor is made of a metal material because it is necessary to maintain strength. For this reason, static electricity in the room or static electricity carried by the user when the endoscope is connected to the endoscope processor may be transferred to the connection portion and charged. If the amount of charge at the connection part increases, the signal cable passing through the connection part discharges, and the electronic components on the board connected to the signal cable may be destroyed.

  In order to prevent the above problem, Patent Document 1 discloses an endoscope processor having an electrostatic induction unit including a parallel circuit of a capacitor and a resistor. In the endoscope processor described in Patent Literature 1, even when static electricity enters the connection between the endoscope scope and the endoscope processor, it is possible to discharge electricity to the capacitor side.

JP 2017-64040 A

  However, in the endoscope device described in Patent Literature 1, when static electricity enters the connection portion, a large current flows through the capacitor, and at that time, an induced current may be generated in the signal cable. The induced current generated in the signal cable may damage electronic components on the board connected to the signal cable. In other words, in order to prevent failure of the electronic circuit in the endoscope device and to use it safely, it is necessary to prevent discharge from the metal connection to the signal cable and to allow a large current to flow from the connection to the ground. Need to be prevented.

  The present disclosure has been made in view of the above points, and provides a technique for improving the safety of an endoscope apparatus.

  In order to solve the above-mentioned problem, the endoscope is used by fitting a first metal connection part provided in an endoscope scope and a second metal connection part provided in an endoscope processor to connect a plurality of signal lines. In the endoscope apparatus, the second metal connection unit includes a capacitor and a current suppression resistor connected in series with each other, and a discharge resistor connected in parallel with the capacitor and the current suppression resistor. Provided is an endoscope device which is grounded via an electrostatic induction circuit.

  According to the present disclosure, the safety of the endoscope device can be improved.

It is a figure which shows an endoscope apparatus schematically. It is sectional drawing which showed typically the mode that the endoscope scope and the endoscope processor were connected. FIG. 4 is a diagram conceptually showing a range of resistance values at which a current suppression resistor Rr functions well. FIG. 4 is a diagram conceptually showing a relationship between a distance d to a signal line having the shortest distance from a first metal connection portion among a plurality of signal lines and a current suppressing resistance Rr. FIG. 11 is another diagram illustrating a relationship between a distance d to a signal line having the shortest distance from a first metal connection portion among a plurality of signal lines and a current suppression resistor Rr. It is the figure which cut out and showed the 1st connector. It is a figure showing the relation between the 1st connector of a 2nd embodiment, and an electrostatic induction circuit.

<First embodiment>
FIG. 1 is a diagram schematically showing an endoscope apparatus. The endoscope device includes an endoscope scope 1 and an endoscope processor 2. As shown in FIG. 1, the endoscope 1 and the endoscope processor 2 are connected to each other and used to transmit and receive image signals and control signals, and to transmit light for irradiating an observation target. .

  The endoscope 1 is provided with an operation unit 11 for operating a flexible tube. By operating the operation unit 11, for example, the distal end of the tube is bent or an affected part provided at the end of the tube is removed. The forceps to be treated can be manipulated. In addition, an imaging element is provided at the distal end 12 of the endoscope 1, and can image, for example, the inside of a patient. The captured image is converted into an electric signal, sent to the endoscope processor 2, and displayed on a monitor D connected to the endoscope processor 2.

  The endoscope 1 includes a first connector 13 having a control signal cable for transmitting and receiving control signals and an image signal cable for transmitting and receiving image signals, and light emitted from a light source included in the endoscope processor 2. And a second connector 14 having a light guide for transmitting the light through the endoscope processor 2. The endoscope 1 may be provided with a power supply cable in the first connector 13 to supply power, or may be supplied in a non-contact manner using an electromagnetic coil.

  The endoscope processor 2 has an image signal processor, corrects an image signal received from the endoscope 1, and displays the corrected image signal on the monitor D. Further, as described above, the endoscope processor 2 has a light source (not shown) and emits light from the distal end of the endoscope 1 through a light guide (not shown).

  FIG. 2 is a cross-sectional view schematically showing a configuration of a connection portion between the endoscope 1 and the endoscope processor 2 (the second connector 14 is omitted in FIG. 2). The endoscope 1 includes a substrate 15 on which an analog-to-digital converter, a control circuit, a timing generator, a sampling circuit, and the like (not shown) are arranged. Each electronic component provided on the board 15 is connected to a power supply unit (not shown) provided on the board 16 provided in the endoscope processor 2 via an image signal cable, a control signal cable, a power supply cable, and the like. You.

  The electronic circuits provided on the board 15 on the endoscope scope 1 side and the board 16 on the endoscope processor 2 side are called patient circuits. The patient circuit is insulated and grounded from the housing of the endoscope processor 2 for safety reasons (PG is ground in FIG. 2). Therefore, the board 16 on the patient circuit side provided in the endoscope processor 2 is connected to the board 17 on which another image processing chip or the like (not shown) is mounted via the capacitor C. Connected to the housing of the mirror processor 2 and grounded (FG in FIG. 2 is ground).

  Further, the first connector 13 provided in the endoscope 1 has a cylindrical metal connector (first metal connecting portion 18) therein, and the cylindrical metal connector provided in the endoscope processor 2. The connector (the second metal connection portion 19) is fitted. At this time, the female connection pins provided on the connector (first metal connection portion 18) on the endoscope scope 1 side and the male connection pins provided on the connector (second metal connection portion 19) on the endoscope processor 2 side are connected. Connected. The shape of the connector may be square or trapezoidal. Hereinafter, in this specification, the connection pin and the cable connecting the substrates 15 and 16 are collectively referred to as a signal line.

  The second metal connecting portion 19 is connected via an electrostatic induction circuit 20 including a capacitor C and a current suppressing resistor Rr connected in series to each other, and a discharging resistor Rd connected to the capacitor C and the current suppressing resistor Rr in parallel. Grounded.

  As shown in FIG. 2, there is a slight gap at the connection point between the endoscope 1 and the endoscope processor 2, and static electricity in the room air may be charged on the metal connector. is there. In addition, static electricity that has been charged to the user when the endoscope 1 and the endoscope processor 2 are connected may transfer to the metal connector.

  The discharge resistor Rd has a relatively large resistance value, and discharges electric charge accumulated in the capacitor C when static electricity has cumulatively entered the first metal connection 18 and / or the second metal connection 19. It plays the role of discharging little by little.

  The current suppressing resistor Rr serves to prevent the current flowing through the capacitor C from increasing when static electricity enters the metal connector. If the resistance value of the current suppressing resistor Rr is too large, the current suppressing resistor Rr is likely to be discharged from the first metal connection 18 to the signal line. Therefore, the current suppression resistor Rr needs to have a resistance value that does not become too large, and has such a resistance value that the effect of suppressing the current flowing through the capacitor C when static electricity enters the metal connector can be obtained. Need to have Therefore, the resistance value of the current suppression resistor Rr has an upper limit and a lower limit.

  FIG. 3 is a diagram conceptually showing a range of resistance values at which the current suppression resistor Rr functions well. In FIG. 3, the vertical axis indicates the probability P that the endoscope apparatus will malfunction or the electronic substrate is destroyed, and the horizontal axis indicates the resistance value of the current suppression resistor Rr.

  As shown in FIG. 3, as the resistance value of the current suppressing resistor Rr increases, the probability P of malfunction or destruction of the electronic substrate in the endoscope apparatus decreases to reach a minimum value, and thereafter, the current value decreases. As the resistance value of the suppression resistor Rr increases, the probability P of malfunction or breakage of the electronic substrate in the endoscope apparatus increases. In the present disclosure, the vicinity of the value of the current suppression resistor Rr at which the probability P at which the malfunction or the destruction of the electronic substrate occurs in the endoscope device takes a minimum value is referred to as an OK region, and the other resistance values are referred to as an NG region.

  FIG. 4 is a diagram conceptually showing a relationship between a distance d to a signal line having the shortest distance from the first metal connection portion 18 among a plurality of signal lines and a current suppressing resistor Rr. As described above, if the resistance value of the current suppressing resistor Rr is too large, the current suppressing resistor Rr is likely to be discharged from the first metal connection portion 18 to the signal line. On the other hand, if the distance d from the metal connection to the signal line is large, the phenomenon of discharging from the first metal connection 18 to the signal line is unlikely to occur.

  Therefore, by increasing the resistance value of the current suppressing resistor Rr as the distance d increases, it is possible to reduce the influence when the induced current occurs. In other words, the resistance value of the current suppression resistor Rr may be determined so as to be proportional to the distance d to the signal line having the shortest distance from the first metal connection portion 18 among the plurality of signal lines. The inventor has found a relationship between the distance d and the resistance value of the OK region of the current suppressing resistor Rr by repeating the experiment.

FIG. 5 is another diagram showing the relationship between the distance d to the signal line having the shortest distance from the first metal connection portion 18 of the plurality of signal lines and the current suppressing resistor Rr. In FIG. 5, the dotted line indicates the upper limit of the current suppression resistor Rr, and the solid line indicates the lower limit of the current suppression resistor Rr. As shown in FIG. 5, the lower limit and the upper limit of the OK region of the current suppression resistor Rr are defined by the following equations 1, 2 and 3, respectively.
A ≦ Rr ≦ B (Equation 1)
A = 101.232 × d−1011.6016 (formula 2)
B = 101.232 × d + 98.3984 (Equation 3)

  FIG. 6 is a diagram showing the first connector 13 partially cut away. FIG. 6A shows a length L (from the base end of the first metal connection 18 to the base end of the second metal connection 19) in which the signal line and the cylindrical metal connector run in parallel. The length of the first connector 13 is designed to be 5.5 cm, and the distance d to the signal line having the shortest distance from the first metal connection portion 18 among the plurality of signal lines is set to 1.3 mm. Have been. FIG. 6B is a cross-sectional view of the first metal connection portion 18 and a plurality of signal lines.

  For example, in the case of d = 1.3 mm and L = 5.5 cm illustrated in FIG. 6 (a), if Rr ≦ 300Ω, the failure due to static electricity or the destruction of the substrate could be effectively prevented. When the resistance value of the current suppressing resistor Rr is selected so that the above relational expression holds, for example, when the length L in which the signal line and the cylindrical metal connector run in parallel is 10 cm or less, the discharge or induction current of static electricity Was able to be suppressed.

  In general, it is considered that when the length L in which the signal line and the cylindrical metal connector run in parallel increases, the probability that the first metal connection portion 18 discharges to the signal line increases. Therefore, if the resistance value of the current suppressing resistor Rr is made to be inversely proportional to the length L in which the signal line and the cylindrical metal connector run in parallel, it is considered that discharge from the first metal connection portion 18 to the signal line becomes difficult. Can be That is, in the above equation 1, the resistance value of the current suppressing resistor Rr may be determined as (cA) / L ≦ Rr ≦ (cB) / L (c is a constant).

<Second embodiment>
FIG. 7 is a diagram illustrating a relationship between the first connector 13 and the static electricity induction circuit 20 according to the second embodiment. It is effective that the static electricity induction circuit 20 is connected to and provided near a place where static electricity enters the second metal connection portion 19. With this configuration, when static electricity escapes to the ground, the path of the current flowing in the second metal connection portion 19 is shortened, and the influence of the induced current generated in the signal line can be suppressed.

  Therefore, unlike the first embodiment, the second embodiment has a configuration in which the second metal connection portions 19 are grounded via the electrostatic induction circuit 20 at four positions at equal intervals. In this case, static electricity can be efficiently released. The second metal connection 19 may be grounded via the static induction circuit 20 at four or less or four or more positions. In both the first embodiment and the second embodiment, when the electrostatic induction circuit 20 is connected to the second metal connection portion 19 of the first connector 13 which is located at a place where the user can easily touch with the hand. In addition, suppression of the influence of the induced current generated in the signal line increases.

DESCRIPTION OF SYMBOLS 1 ... Endoscope scope 2 ... Endoscope processor 11 ... Scanning part 12 ... End of the endoscope scope 13 ... 1st connector 14 ... 2nd connector 15, 16, 17 ... Substrate 18 ... 1st metal connection part 19 ... second metal connection part 20 ... static electricity induction circuit

Claims (5)

An endoscope apparatus used by fitting a first metal connection provided in an endoscope scope and a second metal connection provided in an endoscope processor to connect a plurality of signal lines,
The second metal connection includes:
A capacitor and a current suppression resistor connected in series to each other, and the capacitor and the current suppression resistor are grounded via an electrostatic induction circuit including a discharge resistor connected in parallel,
Endoscope device. The first metal connection and the second metal connection each have a cylindrical shape,
A plurality of portions of the second metal connection portion are grounded via the electrostatic induction circuit;
The endoscope device according to claim 1. The second metal connection portion is grounded via the static electricity induction circuit at four equally spaced positions,
The endoscope device according to claim 2. A resistance value Rr of the current suppressing resistor is proportional to a distance d to a signal line having the shortest distance from the first metal connection portion among the plurality of signal lines;
The endoscope device according to claim 1. The following formulas 1 to 3 hold between the resistance value Rr of the current suppressing resistor and the distance d between the first metal connection portion and the shortest signal line among the plurality of signal lines.
The endoscope device according to claim 1.
A ≦ Rr ≦ B (Equation 1)
A = 101.232 × d−1011.6016 (formula 2)
B = 101.232 × d + 98.3984 (Equation 3)

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