JP3193470B2 - 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 image pickup device is built in the distal end of an insertion portion of the endoscope.

[0002]

2. Description of the Related Art In a conventional electronic endoscope, an emission surface of a prism arranged at a rear end of an objective optical system and an image receiving surface of a solid-state imaging device are opposed to each other in a distal end of an insertion portion.
The two have been joined directly or via a single flat sheet with the optical path cut out.

[0003]

However, in general, the end of the endoscope insertion section must be formed as thin as possible, so that the prism is formed as small as possible so as not to cut off the optical path.

Therefore, regardless of whether the prism is directly joined to the solid-state image pickup device or via a thin plate, it is difficult to obtain a sufficient adhesive strength because the adhesion of the prism is extremely small in any case. there were.

[0005] For this reason, the adhesive surface may be peeled off due to various directions of force transmitted to the solid-state image pickup device via cables or the like, or changes over time, and the endoscope may not be usable.

[0006] Further, since the thin plate having the optical path cut out has a small adhesive margin formed around the optical path, the adhesive may seep into the field of view and the objective unit may be defective. Not a few.

Accordingly, the present invention provides a tip of an electronic endoscope which can securely fix a prism and a solid-state image pickup device without an adhesive leaking out of a visual field range, and in which the tip of an insertion portion does not become large. The purpose is to do.

[0008]

In order to achieve the above object, the distal end of the electronic endoscope according to the present invention is provided at the distal end of the insertion section with the exit surface of a prism disposed at the rear end of the objective optical system. At the distal end of the electronic endoscope in which the image receiving surface of the solid-state imaging device is opposed to and fixed to the image receiving surface, a frame formed by bending the opposing surface to the side surface of the prism is joined to the prism at the side surface. And the frame formed by bending from the facing surface to the side surface of the solid-state imaging device is joined to the solid-state imaging device and the side portion, and the two frames are further joined to each other at the facing surface. I do.

[0009]

An embodiment will be described with reference to the drawings. FIG. 2 is a front view of a distal end portion of the electronic endoscope, and FIG. 3 is a sectional view taken along the line III-III.

In FIG. 3, 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. The outer periphery is covered with a mesh tube 4 made of a thin metal wire and a jacket tube 5 made of rubber.

Bending operation wire 7 to be remotely pulled
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 most advanced wire guide 8 by silver brazing. Reference numeral 9 denotes a stopper pipe for securing the wire guide 8, which is fixed to the end of the leading-edge 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 tube 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. 3).
It has a circular cross-sectional shape as viewed from above, and the objective optical system 20 is built therein. The objective optical system 20 includes an objective lens group 21 including a plurality of lenses and a color correction filter 2.
2, a low-pass filter 23 made of a quartz plate and a right-angle prism 24 are sequentially arranged from the front side.

The axial direction of the objective lens group 21 is the tip main body 1.
The object in front of the object coincides with the first axis direction. The state-of-the-art lens of the objective optical system 20 is fitted and joined to the observation window 14.

Reference numerals 15 and 16 denote lens frames into which an objective lens group 21 including a cemented lens is fitted and adhered. 17 is the aperture stop. Reference numeral 18 denotes an O-ring for sealing. Reference numeral 27 shown in FIG. 2 denotes an illumination window, from which illumination light transmitted through the illumination light guide fiber bundle is radiated outward to illuminate a subject in front of the distal end main body 11. 2
8 and 29 are air / water nozzles. Reference numeral 30 denotes an outlet of the forceps channel.

As shown in FIG. 3, a solid-state image pickup device 31 is disposed in the body 11b of the distal end main body 11. As the solid-state imaging device 31, for example, a CCD (charge coupled device) is used.

The image receiving surface 31a of the solid-state image pickup device 31 is formed in a square or rectangular shape, and is arranged in parallel with the optical axis of the objective lens group 21. The right-angle prism 24 disposed between the objective lens group 21 and the solid-state imaging device 31 forms a right-angle prism so that the optical axis of the objective optical system 20 intersects perpendicularly with the center of the image receiving surface 31 a of the solid-state imaging device 31. Is reflected in the direction.

Between the right-angle prism 24 and the objective lens group 21, a light-shielding mask 25, a color correction filter 22, and a low-pass filter 23 are joined to each other in a connection tube 19 connected to the rear half of the lens frame 16. The right-angle prism 24 and the low-pass filter 23 are also joined to each other.

Incidentally, as shown in FIG.
Is formed in the shape of a quadrangular cylinder with rounded four corners, and the components contained therein are also formed in the same shape. Then, as shown in FIG. 3, the rear end outer edge of the low-pass filter 23 is chamfered over its entire circumference, and is filled with a black adhesive 26 to block excess light and generate ghosts or the like. Is preventing.

With such an arrangement, the image of the subject on the left in FIG. 3 is formed on the image receiving surface 31 a of the solid-state image sensor 31 by the objective optical system 20. Reference numeral 42 denotes a flexible circuit board on which electronic components (not shown) for performing signal processing of the solid-state imaging device 31 are attached.
Is fixedly connected by soldering to the tip of the.

The solid-state imaging device 3 is provided on the tip side of the circuit board 42.
1 is fixed, and an insulating material 31b is applied to the back side. The solid-state imaging device 31 is formed in a rectangular parallelepiped shape in which a header portion is disposed in the front and rear directions and is longer in the front and rear direction than the width.

The image receiving surface 31a of the solid-state image sensor 31
The frame (element-side frame) 33 joined to the right side is joined to the frame (prism-side frame) 34 joined to the right-angle prism 24, whereby the image receiving surface 3 of the solid-state imaging device 31 is formed.
1a and the exit surface 24a of the right-angle prism 24 are fixed to face each other.

As shown in FIG. 5, the circuit board 42 is bent in a U-shape, and the periphery of the
4 and an insulating tape 45, and the interior space is filled with an epoxy-based adhesive 60 so as to be hardened so as not to be deformed.

In this manner, the objective optical system 20, the solid-state imaging device 31, the circuit board 42, and the signal cable 43 are integrally formed as a single unit as a whole. Through the fixing screw 5
2 fixed.

6 and 7 show a portion where the objective optical system 20 and the solid-state image sensor 31 are joined, and FIG. 1 shows a state before the joining. The element-side frame 33 is formed by bending a thin metal plate into a U-shape and performing black processing, and covers the surface of the solid-state imaging element 31 with a cover glass 31.
c, and is bent along the front and rear side surfaces of the solid-state imaging device 31 from there, and is joined to the solid-state imaging device 31 at the side surface portions (hatched portions in FIG. 1). Therefore, the bonding can be reliably performed with a large bonding area without the adhesive oozing out to the image receiving surface 31a side.

However, the image receiving surface 31a of the solid-state image sensor 31
A window 33a is formed in the element-side frame 33 so as not to block a light image incident on the image receiving surface 31a. The window 33a is provided at the exit surface 24a of the right-angle prism 24.
The exit surface 24a of the rectangular prism 24 is in contact with the peripheral portion 33b of the window 33a. An element-side frame 33 is placed flat on the surface of the header portion of the solid-state imaging device 31 at the front and rear thereof.

The prism side frame body 34 is also formed by bending a thin metal plate into a U-shape and performing black processing.
The right-angle prism 24 is bent from the exit surface 24a side to both side portions thereof, and is joined to the right-angle prism 24 at a side surface portion (hatched portion in FIG. 1). Therefore, the bonding can be reliably performed with a wide bonding area without the adhesive oozing out to the exit surface 24a side of the right-angle prism 24.

A window 34a, which is larger than the exit surface 24a of the right-angle prism 24, is formed in the center of the prism side frame 34, and the side end of the window 34a is
4 to the side portion beyond the bent portion.

The right-angle prism 24 has a window 34a.
And the exit surface 24a of the right-angle prism 24 is positioned so as to protrude on the same plane as the surface of the prism side frame 34 or slightly more.

Therefore, in a state where the element-side frame 33 and the prism-side frame 34 are joined, the bottom surface of the right-angle prism 24 reliably contacts the surface of the element-side frame 33, The thickness and flatness do not affect the optical performance.

The prism-side frame 34 is provided with the element-side frame 3
In accordance with the shape of the flat surface portion 3, the light exit surface 24a of the right-angle prism 24 is formed longer in the front-rear direction. As a result, the two frame bodies 33 and 34 are connected to the exit surface 2 of the right-angle prism 24.
Aside from the image receiving surface 31a of the solid-state imaging device 31, the front and rear sides 4a face each other with a relatively large area.

Therefore, when the frame members 33 and 34 are joined on the opposing surfaces, the joints indicated by oblique lines in FIG. 8 have a large area at a position away from the windows 33a and 34a of the frame members 33 and 34. Can be taken. Therefore, the two frame bodies 33, 33,
34 can be securely joined.

When the frame members 33 and 34 are joined, the right-angle prism 24 side unit and the solid-state image sensor 31-side unit are centered, and the right-angle prism 24 is positioned around the exit surface 24a. Apply a small amount of high-viscosity adhesive to prevent dust from entering.

In this way, as shown in FIG.
When the unit of the right-angle prism 24 and the unit of the solid-state imaging device 31 are joined, the lens barrel 16 of the unit of the objective lens group 21 and the connection tube 19 are joined in a state where focus adjustment has been performed.

Then, the unit formed as a whole as shown in FIG.

[0036]

According to the tip of the electronic endoscope of the present invention,
Since the prisms and the frames joined to the side surfaces of the solid-state image sensor were joined together on the opposing surfaces, a wide adhesive was attached to each adhesive part at a distance from the optical path so that the adhesive did not seep into the observation field of view. The area can be securely bonded, and the frame body is thin and does not take up space, so that the insertion portion can be formed to have a small diameter without making the tip end thick.

[Brief description of the drawings]

FIG. 1 is a partially exploded perspective view of an embodiment.

FIG. 2 is a front view of the embodiment.

FIG. 3 is a sectional view taken along line III-III of the embodiment.

FIG. 4 is a sectional view taken along line IV-IV of the embodiment.

FIG. 5 is a sectional view taken along line VV of the embodiment.

FIG. 6 is a partially enlarged side view in which a part of the embodiment is cut away.

FIG. 7 is a partially enlarged front view in which a part of the embodiment is cut away.

FIG. 8 is an assembly process diagram of the embodiment.

FIG. 9 is an assembly process diagram of the embodiment.

FIG. 10 is an assembly process diagram of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Tip main body 20 Objective optical system 24 Prism 24a Emission surface 31 Solid-state image sensor 31a Image receiving surface 33 Element side frame 34 Prism side frame

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) A61B 1/00-1/32 G02B 23/24 H04N 7/18 H04N 5/30-5/335

Claims (1)

(57) [Claims] 1. A distal end portion of an electronic endoscope in which a light exit surface of a prism disposed at a rear end of an objective optical system and an image receiving surface of a solid-state imaging device are fixed to face each other in a distal end of an insertion portion. In the above, two sides are arranged along the both sides of the prism from the opposite surface.
As both folded but the first frame was found bent over the entire length
Ri together joined in bending surface with adhesive and the prism, along both sides of the solid-state imaging device from said opposing surface
A second frame urchin two sides was found bent over the entire length
Both that in both bent surface and <br/> adhesively joined with the solid-state imaging device, further the both frame bodies to each other, facing each other
A distal end portion of the electronic endoscope, wherein the distal end portion is bonded to a surface around a window formed on the surface with an adhesive .