GB2065313A - Endoscope/camera combination - Google Patents

Abstract

An endoscope 1 is coupled to an SLR camera 7 via a casing 8 containing a beam splitter 9, photocell 11, shutter control circuit 12 and shutter 13. In use, light from a source 2 is directed by light guides 4 and 3 to the object and light reflected from the object is directed by a light guide 5 and the beam splitter 9 to the camera viewfinder. On operating a release 14, both the camera shutter and the shutter 13 open. After a time determined by the photocell 11, the shutter 13 is closed to terminate the exposure. Subsequent to this the camera shutter is closed. <IMAGE>

Description

SPECIFICATION Improvements in or relating to endoscope apparatus The present invention relates to devices for automatically controlling the film-exposure period of a photographic reflex camera arranged for connection to an endoscope having a synchronising contact and/or wire release connector, a beam splitter, the transmitted light of which is fed to the camera and the reflected light of which is fed to a photocell of a control system for determining the exposure period, being situated in the beam path between the proximal end of the endoscope and the camera. Hereinafter, such devices will be referred to as "of the kind described".

Devices of the kind described are referred to in German Patent Specification No. OS 1,951,226 which discloses such a device, for example, in which the image of the subject illuminated via an optical fibre duct of the endoscope is fed via a reflex mirror to the eye of the observer or, after withdrawal of the mirror, to the film of a camera.

This circuit simultaneously activates a photocell which receives a proportion of the image light from a beam splitter situated in the image beam path and thereby generates a signal which is exploited to actuate a diaphragm or shutter between an illuminating device and the light conductor and thereby to terminate the period of exposure of the camera film as a function of the film speed and of the brightness of the image. Due to this arrangement, it is necessary to provide the endoscope proximally with a beam splitter and a photocell together with a signal evaluator circuit and an electrical circuit for pivotal displacement of the diaphragm.

It is an object of the invention to provide a device enabling any desired endoscope to be provided, without adaptation, with an automatic exposure control system for the film of any desired reflex camera connectable thereto.

Accordingly, the invention consists in a device of the kind described for automatically controlling the film-exposure period of a photographic reflex camera arranged for connection to an endoscope having a synchronising contact and/or wire release connector, wherein a casing incorporating a beam splitter situated in the image beam emergent at the proximal end of the endoscope the mensuration beam of which causes actuation via a photocell of an electronic control system presettable to the prevailing film speed which determines the exposure period of the camera film as a function of the intensity of illumination of the subject for a shutter situated in the casing and in the beam path, is interposable between the proximal end of the endoscope and a mirror reflex camera by means of rapid-action coupling means.

This arrangement establishes the possibility of interposing a casing comprising a beam splitter and shutter situated in the beam path of the endoscope between any desired endoscope and any desired reflex camera connected to its proximal end without any alteration of the endoscope or of the camera, a photocell activated by the mensuration beam of the beam splitter lying within an electronic control circuit also housed within the casing, which is switched on together with the camera shutter upon taking exposures.

The casing need thus merely be coupled at one side to the proximal end of the endoscope and at the other to the camera, and a twin wire release for connection to the camera and the electronic system, or a connection to the synchronising contact of the camera, is also required for connection to the control circuit.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawing which diagrammatically shows one embodiment thereof by way of example.

Referring now to the drawing, any desired endoscope utilised for the purpose is shown as 1 and is traversed in conventional manner by an optical fibre conductor which has the light from a projector 2 fed to it via a light conductor cable 4 connectable to the optical fibre conductor 3. The light emerges at the distal end to illuminate a subject an image of which is fed to the proximal end of the endoscope 1 for observation via an optical system or an optical fibre conductor 5.

This image of the subject should be observable by the doctor or other user on the one hand, and should on the other hand be retained by the film of a reflex camera. The reflex camera is constructed in conventional manner, in such manner that the image of the subject may be fed to the observer's eye via a mirror, or to the film 6 of the reflex camera 7 by means of a shutter release or the like.

In doing so, the exposure period of the camera film depends on its speed and on the different brightness of reflection of the subject in question obtained upon checking bodily cavities and areas.

The exposure period resulting from the different brightness of reflection should be adjusted automatically in case of a fixed film speed which is to be taken into account.

To this end, a casing 8 traversed by the image beam 5 of the subject and comprising rapid-action couplings for connection to the endoscope 1 and the reflex camera 7 is interposed between the proximal end of the endoscope 1 and the reflex camera 7. Within the casing 8, the image beam 5 passes through a beam splitter 9 and reaches the camera, so that the image may be observed in normal manner via a mirror and a multi-faceted prism.

A comparatively small proportion of the light, described as a mensuration beam 10, is fed by the beam splitter 9 to a photocell 11 which is situated in an adjunctively switchable electronic control circuit 12 whereby it is possible to close a normally opened shutter 13 situated in the beam path.

During the observation of the subject by the eye of the examining doctor or other operator, the electronic control circuit 12 affected by the mensuration beam 10 via the photocell 1 1, determines the required period of exposure of the camera film as a function of the brightness of the subject, the control circuit being manually preset to the speed of the film utilised in each case.

If the image of the subject is to be recorded by exposure of the film in the reflex camera, the shutter of the camera is opened by actuation of a camera release and the synchronising contact or via an external twin cable release 14, the aperture time of the camera shutter being preset in such manner that it is longer than required for exposure of the camera film, in any event. At the same time, if a twin cable release is used, the secondary release will actuate the electronic control circuit in such manner that the exposure period for the film which is determined and stored during the period of observation is called upon and begins to run and that after its termination, the shutter is closed by means of the control circuit when the exposure period is terminated.

The camera shutter also remains open a little longer in accordance with the said preset longer aperture time, and is not closed until after or upon expiry of this complementary period, whereas the shutter 13 is opened simultaneously so that visual observation of a subject is then possible again.

The shutter 13 may also be installed before or behind the beam splitter 9 in the casing 8, advantageously at the narrowest point of the image beam diameter.

In accordance with the invention, it is also possible and advantageous in particular circumstances to incorporate the endophoto objective 15 or the camera objective in the casing 8, as indicated in the drawing.

The rapid-action couplings hereinabove referred to may take any desired form known in the art and have therefore not been particularly described. For example the casing 8 may be provided in its rear face (to the right of the Figure) with a threaded flange to enable it to be screwed into a lens-coupling flange normally provided on the camera (the so-called M42 mounting) or alternatively and preferably this coupling could be any one of the well-known bayonet couplings such as the Pentax "K" coupling, the Nikon bayonet coupling and so on. At the front face of the casing there could be provided a coupling mount of a similar kind for association with a counterpart mounting on the endoscope lens. The mountings at the front and rear of this casing 8 need not be of the same kind and if necessary, suitable adaptors may be provided to make hybrid couplings.

The casing 8 may be provided with means of the tripod-bush kind for example, to enable it to be supported on a suitable stand as in conventional photographic practice.

Claims (7)

1. A device of the kind described for automatically controlling the film-exposure period of a photographic reflex camera arranged for connection to an endoscope having a synchronising contact and/or wire release connector, wherein a casing incorporating a beam splitter situated in the image beam emergent at the proximal end of the endoscope the mensuration beam of which causes actuation via a photocell of an electronic control system presettable to the prevailing film speed which determines the exposure period of the camera film as a function of the intensity of illumination of the subject for a shutter situated in the casing and in the beam path, is interposable between the proximal end of the endoscope and a mirror reflex camera by means of rapid-action coupling means.

2. A device as claimed in claim 1, wherein the shutter of the camera is opened for a period which is selected to be greater than the aperture time required for the correct film exposure of the shutter controlled by the photo-cell and its electronic circuitry.

3. A device as claimed in claim 2, wherein, after the exposure period determined by the electronic system has elapsed, the shutter unit controlled by the electronic system is interrupted for the duration of the remanent aperture time of the camera shutter plus another complementary period, and is released again subsequent thereto for continued visual observation.

4. A device as claimed in claim 1,2 or 3, wherein the exposure period determined by the photocell sets in simultaneously with the opening of the camera shutter, the electronic system being arranged for actuation by a twin wire release or by connection connected to a synchronising contact of the camera.

5. A device as claimed in any of the preceding claims, wherein the objective or endo-photoobjective is situated in a casing.

6. A device as claimed in claim 5, wherein the shutter is installed in the casing at the point of the most constricted cross-section of the image beam.

7. A device of the kind described, substantially as hereinbefore described with reference to the accompanying drawing.