JPH0481770B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvement of an endoscope using a solid-state image sensor.

[Prior Art and Problems to be Solved by the Invention] In recent years, various endoscopes have been proposed that use solid-state imaging devices such as charge imaging devices (CCDs) as imaging means.

Since the above solid-state image sensor is generally rectangular or square in shape, when it is housed in the distal end of the insertion tube, attaching it to the center of the distal end allows for sufficient space for other illumination means, channels for treatment instruments, etc. I had a problem that I didn't have.

For this reason, as disclosed in Japanese Patent Application Laid-Open No. 58-46922, a conventional method is to reflect the light with a mirror or the like and guide it to the imaging surface of a solid-state image sensor arranged parallel to the axis of the insertion section or the tip. be.

However, even in this conventional example, since the light guide member such as a mirror forming the imaging means is arranged at the center of the distal end, as described above, the illumination means (illumination optical system) or the treatment instrument channel etc. There are problems such as the space becomes narrower, the illumination intensity becomes insufficient, and the treatment tools that can be used are limited, making it difficult to adequately perform treatment using the treatment tools. Furthermore, in the conventional example, the thickness of the solid-state image sensor becomes a wasted space, and the diameter of the tip cannot be reduced accordingly.

The present invention has been made in view of these circumstances, and makes it possible to effectively utilize the space on the tip side of the solid-state image sensor due to the thickness of the solid-state image sensor, thereby making it possible to reduce the diameter on the tip side. The aim is to provide an endoscope with improved performance.

[Means for Solving the Problems] According to the present invention, an endoscope includes: an objective optical system that is parallel to the axis of the distal end of the insertion section and has an entrance opening on the distal end surface of the distal end; an optical element provided at the rear of the objective optical system to bend the emitted light from the objective optical system in a right angle direction; and an optical element provided parallel to the axis of the tip to convert an image formed by the objective optical system into an electrical signal. In an endoscope having a solid-state image sensor, the solid-state image sensor is placed near the central axis of the distal end of the insertion section so as to divide the distal end of the insertion section into two in the radial direction, and its imaging surface is aligned with the optical element. The illumination optical system is disposed facing the light exit surface of the insertion section, the objective optical system and the optical element are built into one of the two halves, and the illumination optical system has an exit opening on the distal end surface of the insertion section. It is characterized by being built into the other part.

[Example] Hereinafter, the present invention will be specifically explained with reference to illustrated examples.

1 and 2 show a first embodiment of the present invention, in which an endoscope 1 is inserted into a body cavity, etc., at the distal end side of a flexible insertion section 2. A tip component 3 is formed with a slightly larger diameter and accommodates an imaging means and an illumination optical system.

The tip (configuration) section 3 has a tip main body 4 formed using a hard member such as metal, and is eccentric to the upper side from the central axis O (indicated by the two-dot chain line) of the tip section 3 for imaging purposes. optical system is installed.

That is, the tip of the insertion section is divided into two in the radial direction, the front end of the through hole formed eccentrically above the center is covered with a cover glass 5, and the objective optical system 6 is installed in the lens holding frame behind the cover glass 5. It is accommodated by 7. The optical axis at the rear of the objective optical system 6
An optical element for bending the light emitted from the objective optical system 6 in the right angle direction is disposed on O'.
In this embodiment, this optical element is formed by a reflecting mirror 10 held by a support frame 8, and this mirror 10 is fixed at an angle of 45 degrees with respect to the optical axis O'.
On the reflected optical axis that is reflected at right angles (downward in the figure) by the reflecting mirror 10, a charge imaging device (CCD), etc. A solid-state image sensor 9 is provided.

In the example shown in FIGS. 1 and 2 above,
The imaging plane is located close to the central axis O, and the central axis O
is arranged parallel to the This solid-state image sensor 9 has an imaging surface formed by arranging a large number of light-receiving elements in a regulated and correct manner on a transparent plate 11 such as a protective glass.
In addition, each electrode can be used to apply a clock signal for reading signals from the hand side via lead wires connected to each terminal fixed by soldering or brazing. It is now possible to read signals (take in signals) by applying .

In the tip part 3, which is decentered and constitutes an imaging means, on the upper side divided into two in the radial direction, an illumination optical system is arranged on the lower side where a wide space is secured due to the eccentricity. be done.

That is, the front end of the through hole formed on the lower side of the tip main body 4 is closed by the light distribution lens 14, and the light guide 15 is inserted through the light distribution lens 14 so that the front end serving as the output end faces the back of the light distribution lens 14. . The light guide 15 is formed by bundling flexible optical fibers, and is inserted into the insertion section 2.
The rear end can be detachably attached to a light source device (not shown). Then, the light from the illumination lamp in the light source device is condensed and irradiated onto the rear end of the attached light guide 15, and the irradiated illumination light is distributed from the front end of the light guide 15. Via the light lens 14, the objective optical system 6 can substantially uniformly illuminate the range that can be imaged on the imaging surface.

In addition, on both sides of the objective optical system 6, there are a treatment instrument channel 16 and an air supply channel 16, as shown in FIG.
A water channel 17 is formed.

A cover member 18 whose front end is enlarged in diameter is fitted on the rear end side of the tip main body 4, and a light guide 15,
A curved portion is formed into which a treatment instrument channel 16, an air/water supply channel 17, etc. can be inserted. The rear side of this curved portion is connected to a flexible portion whose diameter is further reduced (not shown).

Further, the lead wires connected to each electrode of the solid-state image sensor 9 are connected to the operation section on the hand side or a video processing section (not shown) on the outer periphery of the operation section, and the read signals are sent to an amplifier in the video processing section. It's starting to get amplified. If the solid-state image sensor 9 has a mosaic-like three primary color filter arranged in front of the imaging surface, the sample and hold circuit in the amplifier separates each color signal, and the separated color signals are sent to each color amplifier. After further amplification,
The image is displayed on a display device such as a color cathode ray tube while being swept by horizontal and vertical deflection signals.

On the other hand, when using a color sequential illumination method illumination means that sequentially illuminates the rear end surface of the light guide 15 with light of each wavelength of the three primary colors, an analog switch or the like is used, and the analog switch Light of each wavelength is sequentially switched in synchronization with the illumination, and each color amplifier, which is turned on by an analog switch, is amplified every frame period and displayed in each amplified color, so that it can be visually recognized as a color image. There is. It is also possible to display the three primary colors simultaneously using other memory or the like.

According to the first embodiment of the present invention configured in this way, at least the optical axis O' on the incident side (where the incident light is incident) of the objective optical system is eccentrically formed with respect to the central axis O, and the solid-state image sensor 9 is aligned with the central axis O.
Since the solid-state image sensor 9 with a wide imaging surface is disposed near the center (in other words, the part close to the largest diameter of the tip 3) so that the imaging surface faces the direction of the central axis O', Even when used, it has the advantage that the diameter of the tip portion 3 can be made sufficiently small, and that the space for forming the illumination optical system and the like other than the imaging means can be made sufficiently large. Therefore, it is possible to provide sufficient illumination without insufficient illumination intensity, and the image captured and displayed by the imaging optical system is also clear.
Diagnosis can be made accurately. In addition, various treatment instruments can be used for therapeutic treatment using treatment instruments, and appropriate treatment can be performed.

Furthermore, since the distal end portion 3 can be used efficiently, the distal end portion 3 can be made small in diameter, which has the advantage of reducing the pain caused to the patient during insertion.

FIG. 3 shows the tip of a second embodiment of the present invention.

In this embodiment, a prism 20 is used in place of the reflecting mirror 10 in the first embodiment. In addition, a lens 6A forming the objective optical system 6 is attached to the end face of the prism 20 on the incident side, such as by pasting it.

Note that the prism 20 is fixed at a side surface (a surface perpendicular to the paper surface).

The rest is the same as in the first embodiment, and the same members are given the same reference numerals. This embodiment also has almost the same advantages as the first embodiment, in addition to the fact that a part of the lens 6A of the objective optical system 6 is formed by attaching it to the prism 20, and that the refractive index is higher than 1. By using the large prism 20, the optical path to the imaging surface can be made shorter than in the case of the first embodiment, and the length of the tip portion 3A can be shortened accordingly.

In addition to the embodiments described above, for example, without using the light guide 15 as the illumination means,
It is also possible to arrange a lamp or a light emitting diode within the tips 3, 3A. Also, light guide 1
5. The treatment instrument channel 16 and the like do not have to be formed in the above-mentioned positions, and since the space in which they can be formed is widened, there is an advantage that the design etc. become easier.

[Effects of the Invention] As described above, according to the present invention, the distal end of the insertion section is divided into approximately two parts in the radial direction, and the objective optical system and the light emitted from the same optical system are arranged at right angles to one side. In addition to disposing an optical element that bends in the direction,
A solid-state image sensor is disposed on the other side in the vicinity of the central axis of the distal end of the insertion section, with the imaging surface facing the light exit surface of the optical element and parallel to the axial direction.
The outer diameter of the distal end of the endoscope can be made thinner, and a sufficient space for storing other built-in items can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional view of the distal end of an endoscope showing a first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line B-B in FIG. 1, and FIG. The first aspect of the present invention
FIG. 2 is an enlarged sectional view of the distal end portion of an endoscope showing an example. DESCRIPTION OF SYMBOLS 1... Endoscope, 2... Insertion part, 3, 3A... Tip part, 4... Tip body, 6... Objective optical system, 9
...Solid-state image sensor, 10...Reflection mirror, 11...
... Transparent plate, 14 ... Light distribution lens, 15 ... Light guide, 16 ... Channel for treatment instrument, 17 ...
Air supply. Water channel, 20...prism.

Claims (1)

[Scope of Claims] 1. An objective optical system that is parallel to the axis of the distal end of the insertion section and has an entrance aperture on the distal end surface of the distal end, and an objective optical system that is provided behind the objective optical system and that provides light from the objective optical system. An endoscope having an optical element that bends emitted light in a right angle direction, and a solid-state image sensor that is provided parallel to the axis of the tip and converts an image formed by the objective optical system into an electrical signal. , the solid-state imaging device is disposed near the central axis of the distal end of the insertion portion so as to divide the distal end of the insertion portion into two in the radial direction, with its imaging surface facing the light exit surface of the optical element; Further, the objective optical system and the optical element are housed in one of the two halves, and the illumination optical system having an exit aperture on the distal end surface of the distal end of the insertion portion is housed in the other part. endoscope.