GB2034916A

GB2034916A - Endoscope

Info

Publication number: GB2034916A
Application number: GB7930877A
Authority: GB
Original assignee: American Optical Corp
Current assignee: American Optical Corp
Priority date: 1978-11-06
Filing date: 1979-09-06
Publication date: 1980-06-11
Also published as: CA1120904A; DE2944306A1; NL7906056A; FR2440183B3; DE2944306C2; JPS5564208A; GB2034916B; HK18485A; FR2440183A1

Abstract

A fibre optic endoscope is operable under low level object illumination by incorporation of proximal image intensifier 30. The smaller cross-sectional area required for object illuminating fibres 20 permits an increase in image carrying bundle size and/or enlargement or the addition of medical channelling 26. <IMAGE>

Description

SPECIFICATION Endoscope The present invention relates to a fibre optic endoscope with particular reference to medical endoscopes.

In medical endoscopes, as well as in their industrial counterparts, space within the flexible probe is at a premium due to the various functions which must be accommodated, e.g.

image transfer, illumination of the object, articulation, or biopsy channelling. Each of these features is essential to the operation of the instrument and the space given over to each one involves a trade-off in the desired performance.

The present invention provides an endoscope having a proximal main body and flexible probe extending from said main body with flexible image-conducting and object illuminating means both in said probe, said image-conducting means comprising optical fibres affording an image-receiving face of a first cross-sectional area and an image-emitting opposite face; said illuminating means comprising light conducting optical fibres affording an illuminating area considerably less than the area of the image-receiving face for minimizing the space occupied by said illuminating means in said probe; and said main body being provided with proximal image intensification means for receiving images from said imageemitting face of said conducting means and displaying said images for viewing with an intensity increase.

The space requirement for illumination of the object is reduced in favour of a larger diameter image carrying bundle to provide better image quality or improvements in articulation mechanisms and/or incorporation of larger or added medical channelling for greater object accessibility.

By using an image intensifier in an endoscope, an unusually small illuminating fibre bundle, e.g. a single fibre or two, can be used. Image magnification with a fibre optic taper as well as intensification is contemplated.

In previously proposed fibre optic probes, the area given over to illuminating a bundle of fibres is often nearly equal to the area of the image carrying bundle of fibres e.g. as in U.S.

Patents Nos. 3,091,235; 3,902,880 and 3,913,568. The preferred embodiment of the present invention permits the area (cross-sectional size) of the image carrying bundle to be approximately doubled with a corresponding increase in image quality. The single fibre or small number of fibres used for illumination of the object may be made of fused silica to permit transmission of ultraviolet light for fluorescence studies in either medical or industrial application. Intense arc lamps, lasers or U.V. sources may be safely used since very little total energy can be transmitted to the object (e.g. tissues) under examination.

In order that the present invention be more readily understood, an embodiment thereof will now be described by way of example with reference to the accompanying drawing, in which: Figure 1 is a schematic, partially crosssectioned illustration of a preferred embodiment of the invention; and Figure 2 is an enlarged view of the endoscope of Fig. 1 taken along line 2-2.

Referring to the drawings, an endoscope 10 includes a proximal main body section 12 and flexible probe 14 each encased within respectively preferably rigid and flexible supports, i.e. sheathings 16 and 18 shown schematically with dot-dash outline.

Sheathings 16 and 18 are contemplated as being of any conventional form, such as those disclosed in U.S. Patents Nos. 3,091,235; 3,698,099 or 3,913,568. Sheathing 18 in particular, may also include means for articulating the distal end of probe 14 which means may comprise the arrangement illustrated in U.S. Patent No. 3,913,568 or that of either of U.S. Patent Nos. 3,091,235 and 3,162,214. In view of the invention being applicable to any of the known forms of medical endoscopes and their industrial counterparts, details of these instruments will be omitted .

The drawing shows an endoscope providing illuminating fibre means of very small crosssectional area to permit an image carrying bundle to be greatly enlarged in cross-sectional area and/or medical channelling increased in number or size. Usually, the individual fibres making up the image-conducting means and the illuminating means are of.equal cross-sectional area. This is true also of the present invention so that reduction in the number of fibres will give a corresponding reduction in cross-sectional area.

By reduction of the usual great number of illuminating fibres to one or two fibres 20 as illustrated, there is provided a correspondingly larger free space 22 within sheath 18 of probe 14. This then becomes available for enhancement of the performance of other functions of the endoscope, e.g. enlarging its image-conducting fibre bundle 24, enlarging a biopsy channel 26 or the addition of other channelling, e.g. medical catheters and the like. For example, assuming that the illuminating fibres 20 (Fig. 2) would normally occupy approximately the cross-sectional area of image-conducting bundle 24, the saving of space within sheath 18 by incorporation of only the two fibres 20 for the above-mentioned purposes is readily apparent.While the schematic illustrations of Figs. 1 and 2 show much unused space 22, it is to be understood that it is this space afforded by the reduction in number and/or size of illuminating fibres that is made available for aforesaid improvement of other functions of the endoscope Fibres 20 may be formed of glass of fused silica, the latter permitting transmission of ultraviolet light for fluorescence studies in either medical or industrial applications. Illumination from source 28 may be in any desired form including that produced by intense arc lamps, lasers or high energy U.V.

sources safely used according to the present invention since very little total energy would be transmitted distally to tissues in medical applications, for example.

In view of there being a loss of object illumination by reduction from the usual large number of illuminating fibres to the aforesaid one or two fibres 20, it is contemplated that this loss be compensated for with incorporation of an image intensifier 30 at the proximal end of endoscope 10. The illustrated image intensifier 30 is of the fibre optic proximity focussed type, details of which can be had by reference to U.S. Patents Nos. 3,141,105; 3,321,658 and 3,436,142 With an object 32 illuminated by fibres 20 and imaged by objective lenses 34 upon end 36 of fibre bundle 24, the image may be transferred from bundle 24 into fibre optic taper 38 for enlargement prior to intensification by image intensifier 30 and viewing upon face 40 of intensifier 30 with eyepiece lens means 42. Those interested in details of fibre optic tapers may refer to U.S. Patents Nos.

2,992,516; 2,992,587 and 3,187,627.

An exemplary specific configuration of the system shown in Figs. 1 and 2 may include a fibre optic taper (bundle) 38 adaptable to enlarging an image carried by bundle 24 by a factor of four. The flexible bundle 24 may have an active diameter of approximately 3 mm so that the enlarged diameter is approximately 12 mm with image intensifier 30 having an active aperture of this latter diameter. With a single fibre size for flexible bundle 24 being 15 microns (corresponding to a resolving power of about 40 line pairs per millimetre), an enlargement of 4 X will reduce the resolution requirement at intensifier 30 to 10 line pairs per millimetre which can be readily conventionally transmitted.

With the aforesaid output image diameter of approximately 12 mm, an eyepiece magnification of approximately 5 X will meet normal viewing requirements. It should be understood, however, that the intensified image output at face 40 may be directly coupled to a television camera or other such means for display on a monitor (screen).

The image intensifier may compensate fully for the reduction in illumination of the object and in some case may overly compensate for the reduction thus producing a brighter image than would have been available normally.

Those skilled in the art will readily appreciate that various other modifications and adaptations of the precise forms of the invention here shown may be made to suit particular requirements.

Claims

1. An endoscope having a proximal main body and flexible probe extending from said main body with flexible image-conducting and object-illuminating means both in said probe, said image-conducting means comprising optical fibres affording an image-receiving face of a first cross-sectional area and an image-emitting opposite face; said illuminating means comprising light conducting optical fibres affording an illuminating area considerably less than the area of the image receiving face for minimizing the space occupied by said illuminating means in said probe; and said main body being provided with proximal image intensification means for receiving images from said imageemitting face of said conducting means and displaying said images for viewing with an intensity increase.

2. An endoscope according to claim 1, wherein said image-conducting means comprises a great multiplicity of juxtaposed optical fibres, and said illuminating means comprises considerably fewer optical fibres than said image-conducting means.

3. An endoscope according to claim 2 wherein said illuminating means comprises two light-conducting fibres.

4. An endoscope according to claim 1 wherein said illuminating means comprises a single fibre.

5. An endoscope according to claim 1, 2, 3 or 4 including image magnifying means between said image-emitting face of said image-conducting means and said image intensification means.

6. An endoscope according to any one of the preceding claims including medical channelling in said probe.

7. An endoscope substantially as hereinbefore described with reference to the accompanying drawing.