JPH04114623A - Camera for endoscope - Google Patents

Abstract

PURPOSE:To achieve a finer diameter of an inserting part and a shorter axial length of a hard tip part by joining a protective glass out a photo detecting surface of a solid image sensor while a lens is fastened on the surface thereof as positioned the closest to an imaging side composing a group of objective lenses. CONSTITUTION:A protective glass 13 comprising a balanced plane plate is fastened on a solid image sensor 12 by a means for adhesion on the like. A lens 4a is bonded on the surface of the protective glass 13 as positioned the closest to an imaging side composing a group of objective lenses 4. As the protective glass 13 is so arranged to be fastened direct on the solid image sensor 12 provided on a substrate 11 to leave no excess of space between members, the overall length can be reduced remarkably from the tip of a tube 5 to the substrate 11. This allows the shortening of the length of a hard tip part 1 comprising a tip part body 1a and a ring part 1b. Even in a three-layer junction structure, neither the lens 4a nor the protective glass 13 interferes with a wire 16. The solid image sensor 12 is smaller in outer diameter size than the lens 4a and the protective glass 13 has a size enough to cover a photo detecting surface 12a of the solid image sensor 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to an imaging device that is attached to the distal end of an insertion section of an endoscope.

[Prior art 1] An electronic endoscope has an imaging device built into the distal end of its insertion section.
A solid-state imaging device such as a CD is provided, and the solid-state imaging device is arranged at the imaging position of an objective lens attached to an observation window provided in the rigid distal end portion of the insertion section. This solid-state image sensor is mounted on a substrate, and wiring for electrical connection is spanned between the solid-state image sensor and the substrate by wire bonding means. In addition, a frame body is attached to the board so as to surround the solid-state image sensor, and a protective glass made of a parallel plane plate is attached to the top surface of the frame body at a position that does not interfere with the wiring. The solid-state imaging device is located in a sealed chamber surrounded by glass, and nitrogen gas or the like is filled in the sealed chamber.

[Problem to be Solved by the Invention 1] By the way, an endoscope is inserted into the body, and the insertion portion thereof is formed as small in diameter as possible, and a hard distal end portion constituting the distal end portion is formed. It is also necessary to shorten the length in the axial direction. In particular, for devices that are inserted into extremely narrow channels, such as bronchoscopes, even if the diameter is extremely small, such as 1 mm or less, the outer diameter of the insertion section and the axis of the rigid tip may be affected. If the length in this direction can be shortened, it is advantageous for ease of insertion of the endoscope and for alleviating patient pain.

In light of the above, various efforts have been made to reduce the diameter of the insertion section and the axial length of the rigid tip, and at present miniaturization has reached almost the limit. It has become to.

Here, the built-in parts of the insertion section of the electronic endoscope include:
In addition to the above-mentioned imaging device, there is a light guide made of an optical fiber bundle that transmits illumination light, a treatment instrument insertion channel, and an air and water supply pipe. The light guide, the treatment instrument insertion channel, and the air/water supply pipe are usually made of flexible members, and therefore, these members do not limit the axial length of the rigid distal end portion in the insertion portion. Further, although these members are related to the thickness of the insertion portion, it is not possible to arbitrarily reduce the diameter of these members due to their functions. On the other hand, the imaging device is directly related to the axial length and external dimensions of the rigid tip, and in recent years, the various elements and functional parts that make up this imaging device have become increasingly important. As imaging devices are becoming smaller, it is possible to further reduce the size of the layers depending on how the imaging device is assembled.

However, as mentioned above, if a frame body surrounding the solid-state image sensor is provided on the board and a protective glass is attached to this frame, even if the solid-state image sensor is miniaturized, the entire image sensor This is not as effective in making the structure compact, especially since the frame and protective glass must be held so that they do not interfere with the wire bonding wiring, even if a small solid-state image sensor is used. However, it is not possible to downsize the entire imaging device.

The present invention has been made in view of the above-mentioned problem, and its purpose is to reduce the diameter of the insertion section as a whole and the axial direction of the rigid distal end by miniaturizing the imaging device as much as possible. An object of the present invention is to provide an imaging device for an endoscope that can shorten the length of the endoscope.

Means for Solving the Problems 1 In order to achieve the above-mentioned object, the present invention provides a protective glass made of a parallel plane plate that is thicker than the amount of protrusion of the wiring from the surface of the light receiving surface of the solid-state image sensor. In addition to joining the
A lens that constitutes the objective lens group and is located closest to the image forming side is fixed to the surface of the protective glass, and the lens covers at least the electrode portion of the solid-state image sensor, and a sealing material that protects the wiring is provided. The feature is that the area from between the lens and the solid-state image sensor to the electrode section on the substrate side is filled with the liquid.

[Function] A frame body, etc. is provided on the substrate by directly bonding a protective glass onto the solid-state image sensor mounted on the substrate, and directly fixing the lenses constituting the objective lens group to this protective glass. By forming a three-layer bonded structure on this substrate, the length in the axial direction from the objective lens group to the imaging device can be shortened.

Here, wiring formed by wire bonding is usually bridged between the solid-state imaging device and the substrate, but this wiring forms a mountain or an arch shape from the surface of the solid-state imaging device and connects to the electrodes on the substrate side. It is designed to be connected to the section. That is, a portion of the wiring protrudes from the surface of the solid-state imaging device, and when assembling the imaging device, it is necessary to prevent such protruding wiring from interfering with other members. To this end, first, the protective glass that is directly bonded to the solid-state image sensor is designed to avoid the arrangement position of the electrode portion of the solid-state image sensor and to completely cover the light-receiving surface. Moreover, the thickness of the protective glass is made larger than the amount of protrusion of the wiring.

This allows the protective glass and lens to be incorporated without interfering with the wiring. The lens is fixed on a protective glass bonded to the solid-state image sensor, and the wiring is located below the surface of this protective glass.
There is no longer any restriction between the outer diameter of the lens and the size of the solid-state image sensor. Therefore, it is possible to use a solid-state image sensor having an outer diameter smaller than the outer diameter of the lens.

In recent years, solid-state imaging devices have become highly integrated,
It has become possible to use smaller elements. In addition, since endoscopes do not require very high resolution compared to normal television photography, elements with a small number of pixels can be used, and from this point of view, solid-state imaging It is expected that the device will become smaller. and,
If the solid-state image sensor can be made smaller, the substrate can also be made smaller accordingly.

Based on the above, the axial length of the imaging device can be shortened by assembling the solid-state imaging device, the protective glass, and the lens closest to the subject that constitutes the objective lens group into a three-layer structure. Moreover, by using a solid-state image pickup device having a smaller size and shape than the outer diameter of the lens, and by using a substrate commensurate with this, the outer diameter of the entire solid-state image pickup device can also be reduced. As a result,
The diameter of the insertion portion can be reduced and the axial length of the rigid tip portion can be shortened.

Furthermore, in order to protect the wiring between the solid-state image sensor and the substrate, a sealing material is used, and the picture electrodes and wiring are embedded in this sealing material. Here, since the lens covers at least the electrode part on the solid-state image sensor side, the connection part of the wiring to the solid-state image sensor can be more completely protected without using something like a frame. . Further, if the lens is dimensioned and shaped to cover the electrode portion on the substrate side, the wiring protection function is further improved. Plus, the lens.

By forming the protective glass and the solid-state image sensor into a laminated structure, it becomes possible to easily and accurately align the optical axis between the objective lens and the solid-state image sensor.

[Embodiment 1] Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

First, FIG. 1 shows a cross section of the distal end portion of the insertion section of the endoscope. In the same figure, 1 indicates a rigid tip portion, and 2 indicates an angle portion. The rigid tip portion 1 has a tip body 1a and a ring portion 1b connected thereto, and an observation window 3 is provided in this tip body 1a. It has been established.

A lens barrel 5 equipped with an objective lens group 4 is inserted through the observation window 3, and the lens barrel 5 is extended into the ring portion lb.

IO indicates an imaging device, and the imaging device IO is a rigid tip portion 1.
It is installed in the ring part lb in the. This imaging device IO is constructed by providing a solid-state imaging device 12 fixedly attached to a substrate 11. Further, a protective glass 13 made of a parallel plane plate is fixed onto the solid-state image sensor 12 by means of adhesive or the like. Furthermore, this protective glass 13
A lens 4a, which constitutes the objective lens group 4 and is located closest to the image forming side, is bonded to the surface of the lens 4a. This lens 4a is attached to a fixed barrel 5a in a lens barrel 5.
A movable tube 5b to which other lenses are attached is inserted into the lens a, and focusing can be performed by adjusting the position of the movable tube 5b in the axial direction.

As shown in FIGS. 2 and 3, the protective glass 13 is
It has a size and shape that covers the area of the light receiving part 12a in the solid-state image sensor 12, and a protective glass 1 is provided in the area where the plurality of electrodes 14 provided on the surface side of the solid-state image sensor 12 are arranged.
2 is not covered. Then, this electrode 14 and the substrate 1
A wiring 16 is installed between each of the electrodes 15 provided in the same number in 1 by wire bonding means. Here, the wiring 16 has an arch shape and has a portion that protrudes from the surface of the solid-state image sensor 12. The thickness of the protective glass 12 is slightly larger than the length of the protruding portion of the wiring 16.

Furthermore, the solid-state image sensor 12 is now being used with extremely small dimensions and shape, and for this reason, the lens 4a is
has a larger diameter than the solid-state imaging device 12, and extends not only to the part where the electrode 14 is formed but also to the part where the wiring rod protrudes the most, and further to the vicinity of the part where the electrode 15 is disposed on the substrate 11 side. In order to protect the wiring 16 from disconnection, a sealing material 17 is used, and the wiring 16 is embedded in the sealing material. Moreover, this sealing material 17 is designed to penetrate into the region between the solid-state image sensor 12 and the lens 4a.

The present embodiment is constructed as described above, and the protective glass 13 is fixedly provided to the lens 4a, and the solid-state image sensor 12 provided on the substrate 11 is directly fixed to the protective glass 13. Since there is no extra space between these parts,
The entire length from the tip of the lens barrel 5 to the substrate 11 can be significantly shortened, and the length of the rigid tip portion 1 consisting of the tip body 1a and the ring portion 1b can be shortened. Further, even with this three-layer bonded structure, both the lens 4a and the protective glass 13 do not interfere with the arrangement 49116.

The solid-state image sensor 12 has a smaller outer diameter than the lens 4a, and the protective glass 13 is sized to cover the light-receiving surface 12a of the solid-state image sensor 12. The size can be reduced regardless of the size. Therefore, as the solid-state image sensor 12, the one with the smallest size and shape is used on the condition that the required resolution can be obtained. By using the small-sized solid-state image sensor 12 in this way, the size of the substrate 11 can also be reduced. Here, the imaging device 10 is arranged such that its substrate 11 is disposed in a direction perpendicular to the axis of the insertion section, and if the outer diameter of the substrate 11 can be reduced, the insertion portion can be inserted by that amount. It is possible to reduce the diameter of the part. From the above, by configuring the imaging device IO in this manner, it is possible to shorten the length of the rigid distal end portion 1 in the axial direction and to reduce the diameter of the entire insertion portion.

Moreover, it is arranged by lens 4a! ! Since the wiring 16 is covered and the sealing material 17 is filled in the wiring 16, the lens 4a functions to protect the wiring 16, preventing disconnection of the wiring 16,
Especially the relatively weak part, Kai! The connection portion of the 1I16 with the electrode 14 on the solid-state imaging device 12 side can be reliably protected.

Furthermore, since the lens 4a constituting the objective lens group 4 is bonded to the solid-state image sensor 12 via the protective glass 13, it is extremely easy to align the optical axis between the objective lens group 4 and the solid-state image sensor 12. You will be able to do this more reliably.

Next, FIG. 4 shows a second embodiment of the present invention. In this embodiment, a substrate 11' on which a solid-state image sensor 12 is mounted
A recess 11a' is formed in the recess 11a'.
A solid-state image sensor 12 is mounted inside.

Further, the electrode 15 is provided on a thick portion of the substrate 11'.

With this configuration, the difference in height between the electrode 14 of the solid-state image sensor 12 and the electrode 15 on the substrate 11' side is reduced by the height of the recess 11a'. As a result, the electrode 14
．． The amount of protrusion of the wiring Ia 16' formed by the wire bonding means between 15 and 15 can be reduced, the thickness of the protective glass 13' can be shortened, and the length of the rigid tip portion 1 in the axial direction can also be shortened. It becomes possible.

[Effects of the Invention] As explained above, the present invention provides a solid-state image sensor with a protective glass bonded to it, and a lens on the closest image forming side constituting an objective lens group is attached to this protective glass. None, and a protective glass is formed on the light-receiving surface of the solid-state image sensor to be thicker than the protrusion of the wiring from the surface, and the lens covers at least the electrode portion of the solid-state image sensor. Since the area between the solid-state image sensor and the electrode section on the substrate side is filled with a sealant for embedding the wiring, the outer diameter and thickness of the entire image sensor can be reduced. The length in the axial direction of the rigid distal end portion of the insertion portion of the endoscope can be shortened and the diameter of the insertion portion can be reduced by the amount of space saved for mounting the imaging device.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the present invention, in which FIG. 1 is a sectional view of the distal end portion of the insertion section of an endoscope equipped with an imaging device, and FIG. top view of the device;
Fig. 3 is a sectional view taken along the line ■-■ of Fig. 2, and Fig. 4 is a cross-sectional view of the second embodiment of the present invention.
FIG. 2 is a cross-sectional view of an imaging device showing an example. 1: tip rigid part, la: tip main body, 1b = ring part,
4: Objective lens group, 4a: Lens, 5: Lens barrel, 10: Imaging device, 11.11': Substrate, lla': Concave part, 12:
Solid-state image sensor, 12a: Light receiving section, 13.13': Protective glass, 14.15: Electrode, 16.16': Wiring, 17:
sealing material. Figure 1

Claims (2)

[Claims] (1) It is built into the tip of the insertion section of the endoscope, and consists of a substrate and a solid-state image sensor mounted on the substrate, and between the electrode section on the surface of the solid-state image sensor and the electrode section on the substrate side. In an imaging device formed by spanning wiring, a protective glass made of a parallel plane plate is bonded to the light-receiving surface of the solid-state image sensor, and the thickness is thicker than the amount of protrusion of the wiring from the surface, and the surface of the protective glass is bonded to the light receiving surface of the solid-state imaging device. A lens that constitutes an objective lens group and is located closest to the image formation side is fixed, and the lens covers at least the electrode portion of the solid-state image sensor, and a sealing material that protects the wiring is attached to the lens and the solid-state image sensor. An endoscope imaging device in which the area between the board and the electrode part on the substrate side is filled. (2) The substrate is provided with a concave portion for accommodating the solid-state image sensor, and the electrode portion is provided in a thick portion, thereby reducing the difference in level between the two electrode portions. The endoscope imaging device according to item (1).