JP3072173B2 - Electronic endoscope tip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distal end of a so-called electronic endoscope in which a solid-state imaging device is built in the distal end of an insertion section of the endoscope.

[0002]

2. Description of the Related Art In a so-called electronic endoscope, a circuit board on which an electronic circuit connected to a solid-state imaging device is wired is arranged in the distal end of an insertion portion of the endoscope, and a signal cable in which a plurality of signal lines are bundled. Is inserted into the insertion portion to connect each signal line to the wiring of the circuit board.

FIG. 6 shows such a conventional circuit board 80.
2 shows a state where the signal line 91 of the signal cable 90 is soldered. 81 is a solid-state imaging device. A core wire 92 of each signal line 91 is soldered to a connection terminal 82 of the circuit board 80, and a shield 93 surrounding the core wire 92 is individually soldered to a ground connection terminal 83 formed near each connection terminal 82. I have. 94 is a jacket tube of the signal cable 90.

When the circuit board 80 is mounted on the distal end of an electronic endoscope, the circuit board 80 is bent at a broken line so as to have a trapezoidal cross section as shown in FIG. Of synthetic resin 85 is filled.

[0005]

In the conventional structure as described above, the position at which the shield 93 is soldered to the circuit board 80 is much larger than the diameter of the signal cable 90. In order to wire up to the position, it is necessary to increase the distance from the distal end of the jacket tube 94 to some extent so that the signal line 91 is exposed.

However, in a structure in which the signal line 91 is exposed, the signal line 91 may be easily broken. Therefore, as shown in FIG. Must be applied and hardened to reinforce the mechanical strength.

Therefore, the length of the hard portion at the distal end of the insertion portion of the endoscope is from the distal end to the rear end of the adhesive 86,
There are drawbacks in that the hard part is long and the pain given to the patient is great, and the guide is not easily turned in the body cavity.

After soldering, the circuit board 80
When bending the wire, there are disadvantages such as a problem that the signal line 91 is twisted and the soldering is removed, and it is difficult to solder the shield 93 individually near the core wire 92. .

Accordingly, the present invention provides a distal end portion of an electronic endoscope which can shorten the length of the hard portion at the distal end of the insertion portion, and is excellent in workability of soldering between the signal line and the circuit board and excellent bonding stability. The purpose is to do.

[0010]

In order to achieve the above object, the tip of the electronic endoscope according to the present invention is arranged such that an electronic circuit connected to a solid-state imaging device is provided inside a tip of an insertion portion of the endoscope. The end of an electronic endoscope in which a signal cable formed by bundling a plurality of signal lines formed by surrounding a core wire with a shield is inserted into the insertion portion, and the signal lines are connected to the circuit board. In the portion, the shield is drawn out from each end portion of the plurality of signal lines, the drawn-out portion of the shield is wound around the outer periphery of the bundle of core wires in an annular shape, and the annular portion is soldered to the circuit board. It is characterized by.

[0011]

An embodiment will be described with reference to the drawings. FIG.
3 shows the distal end of the insertion section of the endoscope.

In FIG. 1, reference numeral 1 denotes a curved portion formed at the tip of an elongated flexible tube forming an insertion portion, and a plurality of node rings 2 are rotatably connected by rivets 3. The outer circumference is a mesh tube 4 made of a thin metal wire and an outer jacket tube 5 made of rubber.
Covered by

A bending operation wire 7 to be pulled remotely
Are inserted in a wire guide 8 projecting inward from each node ring 2 so as to be able to advance and retreat. The distal end of each bending operation wire 7 is fixed to the wire guide 8 by silver brazing or the like. Reference numeral 9 denotes a stopper pipe for securing the wire guide 8, which is fixed to the end of the wire guide 8 by silver brazing or the like.

Reference numeral 11 denotes a distal end main body connected to the distal end of the bending portion 1 via a connecting cylinder 12;
And a head 11a made of an electrically insulating plastic and joined to a tip portion thereof.

The tip body 11 is located on the tip side (left side in FIG. 1).
It has a circular cross-sectional shape as viewed from above, and an objective optical system 13 is built in the head 11a. The objective optical system 13 is composed of a plurality of lenses, the axial direction of which is coincident with the axial direction of the distal end body 11, and an object in front is an object. The observation window 14 is formed by the most advanced lens of the objective optical system 13.

Reference numerals 15 and 16 denote lens frames into which the respective lenses of the objective optical system 13 are fitted and bonded, and the outer lens frame 15 is joined to the head 11a of the distal end body. 17 is the aperture stop. Reference numeral 18 denotes an O-ring for sealing.

Light guide fiber bundle 21 for illumination
The emission end 21a is fixed to the head 11a of the distal end body with its axis parallel to the objective optical system 13. A light distribution lens (concave lens) 22 for increasing the light distribution angle of the emitted illumination light is disposed on the end face.

As described above, the light distribution lens 22 is connected to the illumination window 2.
The illumination light transmitted through the illumination light guide fiber bundle 21 illuminates a subject in front of the distal end portion main body 11.

A solid-state image sensor 31 is disposed in the body 11b of the tip body 11. As the solid-state imaging device 31, for example, a CCD (charge coupled device) is used. The image receiving surface 31 a of the solid-state imaging device 31 is formed in a square or a rectangle, and is arranged parallel to the central axis of the objective optical system 13.

The objective optical system 13 and the solid-state imaging device 3
1, a right-angle prism 33 is disposed, and the optical axis of the objective optical system 13 is adjusted to the image receiving surface 31a of the solid-state imaging device 31.
Are reflected in a perpendicular direction so as to intersect perpendicularly with the center.

The right angle prism 33 and the objective optical system 13
And a connecting cylinder 34 connected to the rear half of the lens frame 16.
A light-shielding mask 37, a color correction filter 35, and a low-pass filter 36 are interposed therein.

With such an arrangement, the image of the subject on the left side of FIG.
Is formed on the image receiving surface 31a. The circuit board 40 to which the solid-state imaging device 31 and other electronic components 41 are attached is made of one flexible electrically insulating plastic plate as a material as shown in FIG.

Signal cable 5 connected to circuit board 40
Numeral 0 denotes a large number of signal lines 51 which are insulated from each other and bundled and passed through a jacket tube 52. Each signal line 51 is formed by surrounding a core wire 53 with a shield 54 over the entire length.

The signal cable 50 is connected to the circuit board 4
In connection with the shield 0, first, as shown in FIG. 3, after removing a predetermined range of the distal end portion of the jacket tube 52, a net-like shield 54 is formed from each signal line 51 to near the end of the jacket tube 52. Loosen and pull out.

At this time, as shown in FIG. 3, a tube covering each signal line 51 outside the shield 54 is cut off at a portion where the shield 54 is drawn out, and a tube covering the core wire 53 is a solder at the tip. Except for the allowance, leave it as it is. Further, the distal end portion of the jacket tube 52 is tightened with a thread 56, and the jacket tube 52 is connected to the internal signal line 51.
Fix so that it does not move with respect to.

Next, as shown in FIG. 4, the drawn-out portion of the shield 54 is annularly wound around the outer periphery of the bundle of the core wires 53 at a position slightly apart from the end of the jacket tube 52. Then, solder is attached to the annular portion of the shield 54 to be solidified.

After this state, as shown in FIG. 2, the annular portion of the shield 54 is attached to the circuit board 5.
0 to the ground connection terminal 43. In this way, the signal lines 51 are arranged straight from the rear up to the position where they are soldered to the ground connection terminal 43. On the other side, only the thin core wire 53 is connected to each connection terminal 4.
4 is bent toward the connection terminal 44, and its tip is connected to each connection terminal 44.
Soldered to.

As described above, since the signal wire 51 extends straight from the signal cable 50 behind the position where it is soldered and fixed to the ground connection terminal 43, the end of the jacket tube 52 and the annular portion of the shield 54 are formed. Signal line 5 between
The length of one exposed portion can be extremely reduced.

Accordingly, it is possible to keep the distal end of the jacket tube 52 from leaving the rear end position of the circuit board 40. Further, since only the thin core wire 53 is bent and wired, the wiring operation can be performed easily and reliably.

After the soldering is completed, the circuit board 40 is bent at a broken line portion shown in FIG. 2 to form a trapezoidal cross section as shown in FIG. 5, and an electrically insulating synthetic resin 46 is provided therein. Fill.

When the circuit board 40 is bent, only the thin core wire 53 is bent inside the circuit board 40. Therefore, the force applied to the soldered portion due to the twisting of the wiring when the circuit board 40 is bent is extremely small, and a large force for peeling off the soldering is not applied.

A shield member 48 and an insulating tape 49 are provided around the outer periphery of the circuit board 40 formed in a trapezoidal shape in this manner.
Is coated. Then, as shown in FIG. 1, an adhesive 47 is applied to the outer circumference of the distal end of the jacket tube 52 so as to surround the binding thread 56 and is hardened.

A rectangular prism 33 is joined to the solid-state image sensor 31 provided on the circuit board 40 thus formed to form one unit, and the trapezoidal portion of the circuit board 40 is located immediately adjacent to the rectangular prism 33. It is arranged at the back.
Therefore, when viewed from the objective optical system 13 side, the outer edge shape of the right-angle prism 33 and the circuit board 40 just overlap, and neither travels almost.

[0034]

According to the tip of the electronic endoscope of the present invention,
Since the shield wound around the outer circumference of the bundle of core wires is soldered to the circuit board, the signal lines behind the shield can be arranged straight, and the exposed portion of the signal lines can be extremely short.

As a result, an adhesive is applied to reinforce the exposed portion of the signal line, and the length of the hard portion at the distal end is shortened, so that the insertability is improved and the pain given to the patient is reduced. The sniper performance for the part is improved.

Further, since only the core wire can be bent when the circuit board is bent, the force applied to the soldered portion of the wiring due to the twisting of the wiring when bending the circuit board is extremely small, and the soldering is performed. There is no force that peels off.

Further, since the shields are united and soldered, the soldering operation can be performed very easily.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a distal end portion of an electronic endoscope according to an embodiment.

FIG. 2 is a development view of a circuit board to which a signal cable of the embodiment is connected.

FIG. 3 is a processing step diagram for connecting a signal cable according to an embodiment.

FIG. 4 is a process diagram for connecting a signal cable according to the embodiment.

FIG. 5 is a front cross-sectional view of the circuit board of the embodiment after being bent.

FIG. 6 is a development view of a circuit board to which a signal cable of a conventional example is connected.

FIG. 7 is a front sectional view of a conventional circuit board after bending.

FIG. 8 is a side sectional view of a circuit board to which a conventional signal cable is connected.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Front-end | tip part main body 31 Solid-state image sensor 40 Circuit board 50 Signal cable 51 Signal line 52 Jacket tube 53 Core wire 54 Shield

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-222732 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61B 1/00-1/32 G02B 23 / twenty four

Claims (1)

(57) [Claims] 1. A signal obtained by arranging a circuit board on which an electronic circuit connected to a solid-state imaging device is wired in a distal end of an insertion portion of an endoscope, and bundling a plurality of signal lines formed by surrounding a core wire with a shield. At the distal end of the electronic endoscope in which the cable is inserted into the insertion portion and the signal line is connected to the circuit board, the shield is pulled out from each distal end of the plurality of signal lines, and the bundle of core wires is A distal end portion of an electronic endoscope, wherein a portion of the shield drawn out is wound around the outer periphery in an annular shape, and the annular portion is soldered to the circuit board.