JPS607041Y2 - Endoscope - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to the arrangement of light receiving elements built into an endoscope.

Conventionally, when photographing an object such as the stomach wall using an endoscope, photometry of the photographed light has been carried out. Although photometry is sometimes carried out near the lens, as shown in Utility Model Publication No. 45-8464 and Utility Model Publication No. 47-4376, the photometry element is often placed near the photographic lens, which can reduce noise. There are advantages.

However, there is a limit to how close the photometric axis of the photometric element and the optical axis of the photographing lens can be, which causes parallax, and in endoscopes where the distance between the object and the photographic lens is often short, This kind of parallax is a disadvantage.

However, especially in living body endoscopes, which are extremely compact, it is difficult to provide parallax correction means.

The purpose of this invention is to eliminate the influence of vararax without increasing the size of the device, and for this purpose, the object photographing light beam A photometric device is placed outside.

Next, an embodiment of the distal end camera type endoscope will be described with reference to FIGS. 1, 2, and 3.

FIG. 1 depicts a cross section of the head of a side-viewing endoscope to be inserted into a living body, and 1 is a housing.

2a is an object side lens group consisting of one plano-concave lens; 2b
is an image-side convergent lens group.

(Here, 2a is referred to as a group because it may be composed of a plurality of lenses.

) On the other hand, 3 is an imaging lens group, 4 is an optical fiber bundle for image transmission,
4a is the light receiving end of the fiber bundle.

The other end of this optical fiber bundle faces the eyepiece, but the observation section is not related to the invention and will therefore be omitted.

5 is a mirror prism with roof-shaped reflective surfaces 5c and 5d (second
(Fig.) and a supporting glass block 5b.
I warn you from

The reflective surfaces 5c and 5d have the function of changing the traveling direction of the light flux from the object that enters the object side lens group 2a and inverting the image by the effect of the roof surface.

The light beams reflected by 5c and 5d are converged by the imaging lens group 3 onto the light receiving end 4a of the optical fiber bundle.

6 is a cartridge, and 6a is a film.

In this embodiment, the mirror prism 5 described above also serves as a shutter, and as shown in FIG. 3, film exposure is performed when the mirror prism is retracted from the optical path of the photographing lenses 2a and 2b.

P is a photometric element having an aperture P' in a photovoltaic element such as a selenium solar cell, and is installed at the aperture position of the photographic lens, and the aperture P
The diameter of the aperture is made to match the diameter of the diaphragm aperture S, so that it also serves as a diaphragm.

The reason why it is located close to the aperture position is that the diameter of the light beam used for photographing becomes narrower at this position, so the light receiving section can be brought closer to the optical axis of the photographing lens.

On the other hand, 7 is a lever that supports the mirror prism 5, and this lever 7 is rotatable around a rotating shaft 8.

Therefore, the mirror prism 5 can be moved from the position it occupies in the observation state of FIG. 2 to the position it occupies in the photographing state of FIG.

Reference numeral 9 denotes a member that is coupled to the wire 10 and rotatably attached to the lever 7 with a pin 11.

The wire 10 is connected to a release mechanism (not shown), and when the release operation is performed, the wire 10 is pulled in the direction of the arrow in FIG. It hits 12 and stops.

However, since the lever 7 is biased in the direction of the white arrow in FIG. 2 by a spring or the like (not shown), the mirror prism 5 is in the photographic lens in the normal state.

Reference numeral 13 is a light bulb for object illumination, and a filament 13a for illumination.
and a photographic filament 13b are built in.

Reference numeral 14 denotes an illumination light emission window, which is fitted into the housing 1.

In the above device, a combination of a plane mirror or a fixed semi-transparent mirror and a shutter can be used instead of the mirror prism 5, and the photometric element does not need to have a hole in the photometric surface, but it is preferable to position it axially symmetrically. A plurality of photometric elements are provided so that the photometric section is located at

Next, the action will be explained.

FIG. 1 and FIG. 2 show the observation state, and after inserting the endoscope head into the body, power is supplied to the collation filament 13a.

The light emitted from the lamps exits through the window 14 and illuminates the object.

The light reflected by the object enters the object-side lens group 2a of the photographic lens, is reflected by the reflecting surfaces 5c and 5d of the mirror prism, is converged by the imaging lens 3, and is directed to the light-receiving end 4a of the optical fiber bundle 4.
to form an image.

Therefore, the object is visible to the person observing through the image transmission optical fiber bundle 4.

When the observer captures the area he or she wishes to photograph and performs a release operation, the wire 10 is pulled, the lever 7 is rotated, and the mirror prism 5 is retracted out of the optical path (FIG. 3).

Next, power is supplied to the photographing filament 13b and the photographing state is entered.

The light reflected by the object passes through the lens group 2a, enters the imaging group 2b, and forms an image on the film 6a, but the light beams other than the photographing light beam enter the photometric element P, and the amount of light is measured.

Next, when a certain amount of light is reached, the photographic filament 13
The power supply to b is cut off, the mirror prism 5 returns to its original position, and this completes the - time photographing.

FIG. 4 is a diagram for explaining the effect when the photometric element is arranged behind the object-side lens group of the photographing lens.

Q is the center of a conventionally arranged photometric element fitted into the endoscope housing and provided on the side of the photographic lens.

Wl indicates the light receiving angle of this photometric element, and l□ indicates the central axis.

2a is the front group of the photographic lens, L is the optical axis, P is the center of the photometric element similar to Q, and 12 is its axis.

O is the object plane, and within the usual photographing distance of an endoscope, the deviation A due to the arrangement of the present invention is much smaller than the deviation B when the photometric element is provided on the photographing lens side.

Furthermore, by making the lens group located closer to the object side than the photometric element divergent, the light receiving angle W2 can be made larger than W□ and can be brought closer to the angle of view of the photographic lens.

Furthermore, by providing another photometry section P' at a position symmetrical to the optical axis, it is possible to superimpose measurements on the object plane centered on the optical axis and obtain information measured over the entire object plane at the angle of view. It will be done.

It is guaranteed that photometry is always performed on areas near the optical axis, and by measuring the entire area at the same time, the effect of a specific strongly reflective area is alleviated, so the exposure condition can be adjusted only by the amount of photometry. This type of simple photographing device that determines the value of the image has an excellent effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an embodiment of the present invention. FIG. 2 is a perspective view showing a part of FIG. 1, and FIG. 3 is a perspective view showing another aspect of the same part. FIG. 4 is a diagram for explaining the effect of the present invention. In the figure, 2a is the object side lens group of the photographic lens, 2b is the convergent lens group of the photographic lens, P is the photometric element, and P' is the aperture.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A light beam located behind the object-side lens group of the photographing lens provided on the head of the endoscope, but not behind the final lens, and passing through the object-side lens group outside of the object photographing light beam. What is claimed is: 1. An endoscope comprising a photometer for receiving a light beam having a wide angle of view corresponding to an angle of view for photographing an object. 2. The endoscope according to claim 1, wherein the object side lens group is divergent. 3. The endoscope according to claim 1, wherein the photometric means is provided close to the aperture surface of the photographing lens. 4. The endoscope according to claim 1, wherein the photometric means includes a photometric section at an axially symmetrical position. 5. The endoscope according to claim 1, wherein the photometering means has an aperture in the center thereof through which the photographing light beam passes, and the aperture substantially coincides with the diaphragm aperture.