JPS61254917A - Tip part structure of endoscope - Google Patents

Abstract

PURPOSE:To eliminate the need for cover glass for prevention against the oxidation of a solid-state image pickup element and to reduce the size of the tip part structure of an endoscope by adhering a prism which deflects light from an objective to the solid-state image pickup element directly to the surface of the solid-state image pickup element. CONSTITUTION:The right-angled prism 16 which deflects light passed through a right-angled prism 14 and the objective 15 from the cover glass 12 of an objective optical system to the solid-state image pickup element 20 is adhered directly to the surface 20a of the element 20 at the hard part 11 atop the in- cavity insertion part of the endoscope by using an optical adhesive. Further, the slanting surface 16b of the prism 16 is adhered to a prism holding base 17, which is fixed to the hard part 11 with a fixing screw 18. The prism 16 prevents an integrated circuit pattern on the surface of the element 16 from oxidizing and dust from sticking, and the need for the cover glass for inert gas sealing for the prevention is eliminated to obtain a small-sized, high- performance endoscope at low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an endoscope, and particularly to a tip structure of an endoscope that uses a solid-state image sensor instead of an image fiber.

"Prior art and its problems" Conventional endoscopes form an image of the subject using an objective lens installed at the tip of the part inserted into the body, and guide this image to the eyepiece via an image fiber for observation. Met. However, with the recent development of solid-state image sensors, the image observed by the objective lens is now formed on this solid-state image sensor.
Attempts have been made to display an observed image on a television screen using signals from this solid-state image sensor. An endoscope that uses this solid-state image sensor only needs to use a signal line instead of an expensive image fiber, and there is no need for observation through an eyepiece, so the operator can view it naturally while looking at a TV screen. It can be operated in a comfortable posture and has excellent operability. In addition, the so-called external device attached to the eyepiece of an endoscope has improved resolution compared to a television camera and can electrically process image signals, so it has excellent observation and diagnostic performance. be.

By the way, solid-state imaging devices such as CMOS, COD, and CPD are produced by forming a silicon oxide film on the surface of a silicon single crystal thin plate (wafer), and then using techniques such as photolithography, thermal diffusion, and vapor deposition on top of this. Then, the required integrated circuit pattern was formed. A silicon oxide film, an aluminum film, etc. are exposed on the surface of this integrated circuit pattern, and these are highly susceptible to oxidation and corrosion. For this reason,
The surface is covered with a cover glass, and the space between it and the element surface is sealed with an inert gas such as nitrogen gas. This cover glass also has the role of preventing dust from adhering to the element surface, which is the imaging surface, and preventing dust from forming an image.
In other words, even if dust adheres to the surface of the cover glass,
Since this dust is out of focus, it is not observed as dust.

However, since this cover glass has a certain thickness, there is a problem in that it takes up space as an objective optical system of an endoscope. In other words, in order to reduce patient pain, the endoscope's insertion section into the body is required to be as thin as possible and the rigid tip of the end must be short. If the device is wider than this, it cannot be used as a gastric endoscope.Under these demands, the solid-state imaging device with a cover glass filled with inert gas has become thicker by itself. Because it is stored away, space efficiency deteriorates.
In other words, for example, increasing the diameter and length of the hard part at the tip of the body insertion part, and sacrificing the storage space for other internal objects, may lead to a decline in the light intensity, biopsy ability, etc. of the endoscope. If other built-in components such as a forceps channel for inserting a biopsy tool, a light guide for illumination, etc. are mainly configured, a good arrangement of the objective optical system cannot be obtained.

``Object of the Invention'' The present invention focuses on the problems of endoscopes using conventional solid-state image sensors, proposes an arrangement structure for solid-state image sensors that does not require a cover glass, and solves the above problems. The purpose is to eliminate shortcomings.

"Summary of the Invention" The present invention eliminates the use of a cover glass for sealing in inert gas, which is essential for preventing oxidation of the integrated circuit pattern on the surface of a solid-state image sensor, and instead configures a part of the objective optical system. It is characterized by a prism that is directly bonded to the element surface of the solid-state image sensor. That is, the endoscope of the present invention:
The present invention is characterized in that a prism is provided to bend light from the objective lens toward the solid-state image sensor, and this prism is directly bonded onto the element surface of the solid-state image sensor.

"Embodiments of the Invention" The present invention will be described below with reference to illustrated embodiments. FIGS. 1 and 2 show a first embodiment of the present invention, in which the present invention is applied to a side-viewing endoscope, and a rigid portion 11 at the tip of the body-inserted portion includes: A cover glass 12 for the objective optical system and a cover glass 13 for the illumination optical system are arranged on the side surface thereof. A first right-angle prism 14 is adhered to the inner surface of the cover glass 12, and an objective lens 15 whose optical axis is in the axial direction of the part to be inserted into the body is placed on the optical path of the right-angle prism 14.
is located.

A second right-angle prism 16 is further located on the optical path of this objective lens 15, and one surface of this right-angle prism 16, that is, a surface 16a parallel to the axial direction of the body insertion part 11.
The element surface 20a of the solid-state image sensor 20 is directly bonded to the solid-state image sensor 20 via an optical adhesive. The right-angle prism 16 has its slope 16b adhered to a prism holder 17, and the prism holder 17 is fixed to the rigid part 11 via a fixing screw 18.

FIG. 3 schematically shows how the element surface 20a of the solid-state image sensor 20 and the right-angle prism 16 are bonded together.
6 is directly glued.

Of course, an appropriate protective film other than the optical adhesive 19 may be attached to the element surface 20a.Also, in the figure, the adhesive 19 is filled between the prism 16 and the element surface 20a, but the prism 16 and the element surface 20a may be in close contact with each other.

In this way, when the element surface 20a of the solid-state image sensor 20 is directly bonded to the right-angle prism 16 without using a cover glass, there is ample space within the rigid portion 11.

The element surface 20a is protected by the right angle prism 16 and optical adhesive and is not exposed to the outside air.
There is no risk of this oxidizing or corroding. In particular, corrosive gases such as formalin gas and ethylene oxide gas are used to disinfect endoscopes, and oxidation can be prevented even with these disinfecting gases.

Further, the solid-state image sensor 20 has input/output terminals 20b, 2 for giving a drive signal thereto and for taking out its output.
0c are arranged on both sides of the light guide 21 in the radial direction, as shown in FIGS. 1 and 2. With this arrangement, the signal lines 22.2 connected to the input/output terminals 20b and 20c
2 embraces the light guide 21 from both sides, so the space on both sides of the light guide 21 can be used effectively. Note that this effect is obtained when the prism 16 is not directly bonded to the element surface 20a of the solid-state image sensor 20, except that the solid-state image sensor 20 becomes thicker and the outer diameter increases accordingly. The same result can be obtained even when using a conventional solid-state image sensor of the type that is covered with a solid-state image sensor.

As is well known, the light guide 21 guides illumination light from a light source device outside the endoscope to the cover glass 13 to illuminate the subject. In addition, to explain the other illustrated components, the forceps channel 24 guides various treatment instruments and forceps inserted from the operation part to the tip of the rigid part 11 so as to protrude, an air supply port 25, and a water supply port. 26 is
This removes dirt from the surfaces of the cover glasses 12 and 13.

4 and 5 show an embodiment in which the present invention is applied to a direct-viewing endoscope. In this embodiment, a cover glass 12 is provided at the tip of the rigid part 11, and the right-angle prism 14 is omitted. The relationship between the right-angle prism 16 and the solid-state image sensor 20 is the same as in the first embodiment. That is, the element surface 20a is directly bonded to the right angle prism 16 without using a cover glass for sealing in an inert gas.

In this example, in order to prevent left and right reversal of the observed image,
It is desirable to use a roof prism as the right-angle prism 16, or to electrically invert the left and right sides of the output signal of the solid-state image sensor 20.

Further, in this embodiment, the input/output terminal 2 of the solid-state image sensor 20
A forceps channel 24 is arranged between 0b and 20c, and a signal line 22 connected to the input/output terminals 20b and 20c.
．． 22 are arranged so as to hold the forceps channel 24 from both sides. Light guide 21, air outlet 2
5, and the water inlet 26 are provided in the rigid portion 11, for example, a fifth
Placed as shown.

"Effects of the Invention" As described above, the present invention provides an endoscope using a solid-state image sensor, in which the element surface of the solid-state image sensor is directly bonded to the prism in the objective optical system to prevent oxidation of the element surface. Furthermore, since the objective optical system is protected from dust, the objective optical system can be made smaller by eliminating the need for a cover glass for gas sealing, which was conventionally required. In addition, since the solid-state imaging device can be made thinner, the tip of the endoscope can be placed more effectively, which reduces the burden on the patient by making the tip of the body insertion part smaller in diameter and shortening the rigid part. or increase the possibility of accommodating other internal objects to improve the performance of the endoscope. Even if dust adheres to the prism, since the dust is outside the image formation surface, it will not form an image in the same way as when using a sealing cover glass. By locating the light guide on both sides of a long body such as a forceps channel, the space at the tip can be used more effectively.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of the main parts showing an embodiment of the endoscope of the present invention, 2ryJ is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 shows the element surface of the solid-state image sensor and the prism. FIG. 4 is an optical system diagram showing another embodiment of the present invention,
FIG. 5 is a sectional view corresponding to FIG. 2, showing another example of the arrangement of built-in components in the embodiment of FIG. 4. 11... Rigid part (tip of the part inserted into the body), 12.13...
- Cover glass, 15... Objective lens, 16... Right angle prism, 19... Optical adhesive, 20... Solid-state image sensor, 20a... Element surface, 20b, 20c...
Input/output terminal, 21...light guide, 22...signal line, 24...forceps channel. Patent applicant: Asahi Optical Industry Co., Ltd. Agent: Kunio Miura Shigeru Matsui Figure 2 Figure 3

Claims (2)

[Claims] (1) In an endoscope that is provided with an objective lens and a solid-state image sensor located on the imaging plane of the objective lens at the tip of the endoscope's body insertion part, light from the objective lens is transmitted to the solid-state image sensor. 1. A tip end structure of an endoscope, characterized in that a prism is provided that bends toward the direction, and the prism is bonded directly onto the element surface of the solid-state image sensor. (2) In claim 1, the input/output terminal of the solid-state image sensor includes a light guide disposed inside the body insertion part;
The tip structure of an endoscope that is placed on both sides of a long body such as a forceps channel.