US3608998A

US3608998A - Variable power endoscope

Info

Publication number: US3608998A
Application number: US772522A
Authority: US
Inventors: Walter Rinker
Original assignee: Richard Wolf GmbH
Current assignee: Richard Wolf GmbH
Priority date: 1967-11-25
Filing date: 1968-11-01
Publication date: 1971-09-28
Anticipated expiration: 1988-09-28
Also published as: GB1217939A; FR1591690A

Abstract

An instrument for examining a relatively large area of the interior of a tube or other cavity in the human body in order to locate a lesion therein, and for then examining said lesion in greater detail without removing said instrument from said tube or other cavity. A variable magnification optical system is incorporated in said instrument sufficiently near its outward or proxal end so that the overall magnification of the instrument can be changed without removing it from said tube or other cavity.

Description

United States Patent 3 Claims, 10 Drawing Figs.

11.8. CI 350/42, 128/7, 350/40, 350/49, 350/54 Int. Cl G02b 7/04, G02b 7/ 10 Field of Search 350/40-44,

References Cited UNITED STATES PATENTS Lang Humbrecht Wappler Wolf Strang Hett Littmann Primary ExaminerDavid Schoenberg Assistant Examiner-Toby H. Kusmer Attorney-Otto John Munz 350/42 X 350/42 350/54 350/540 X 350/460 UX 350/54 X ABSTRACT: An instrument for examining a relatively large area ofthe interior of a tube or other cavity in the human body in order to locate a lesion therein, and for then examining said lesion in greater detail without removing said instrument from said tube or other cavity. A variable magnification optical system is incorporated in said instrument suffieiently near its outward or proxal end so that the overall magnification of the instrument can be changed without removing it from said tube or other cavity.

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VARIABLE rowan ENDOSCOPE BACKGROUND OF THE INVENTION The present invention relates to endoscopes, i.e., to the various kinds of well-known optical-medical instruments suitable for examining the interiors of body cavities.

A wide variety of optical-medical instruments for the examination of the internal organs of the human body are found in the prior art. All of these instruments must provide a solution to the common, basic design problem, viz., that they must be adapted to transmit an image of the lesion or other object to be examined through a channel which is long as compared to its diameter. This is accomplished in almost all of such instruments by means of a plurality of intermediate image-forming systems which are disposed between the objective optical system located at the distal end of the instrument and the ocular optical system located at the proxal end of the instrument. A prior art endoscope in which each image-forming system is a pair of lenses is shown in US. Pat. No. 1,680,490, issued to R. H. Wappler on Aug. 14, 1928. Another endoscope of the prior art is shown in U.S. Pat. No. 1,995,196, issued to George Wolfon Mar. 19, 1935.

One disadvantage of the prior art endoscopes is that once the lesion or other object within the body had been located by means of an instrument of relatively low magnification the finer details of the lesion or other object cannot be observed unless the low magnification instrument is withdrawn from the body and a different instrument of higher magnifying power is inserted in its place. Obviously, this is extremely unpleasant for the patient, especially when these instruments are inserted through very small body passages such as the urethra.

SUMMARY OF THE INVENTION In accordance with the present invention, this disadvantage of the known endoscopes is obviated by providing endoscopes with optical systems of variable magnifying power which are located at or near the ocular end of these instruments and thus may be adjusted to vary the magnification while these instruments are in operating position within the body of the patient. For this purpose, an endoscope according to the present invention may be provided with an ocular or eyepiece of variable magnifying power. According to another embodiment of the present invention, one of the intermediate image-forming systems, preferably the one located nearest the eyepiece, is replaced with a suitable optical system of variable magnifying power. When a variable power ocular is used in carrying out the present invention, the field lens may be mounted for selective positioning in one of two different positions located on opposite sides of the ocular image plane, a different magnification corresponding to each of these positions. Mounting means for maintaining a lens in either of two selected positions are well known in the art. An ocular comprising a two-lens combination of continuously variable magnifying power may also be used in carrying out the present invention. As is well known in the art, the magnifying power of such a combination may be continuously varied by correspondingly continuously varying the spacing of the two lenses.

When the present invention is carried out by replacing one of said intermediate image-forming systems with a lens system of variable magnifying power, both of the lenses of the variable power lens system will be made displaceable.

When an endoscope according to the present invention is to be used in conjunction with photographic apparatus for recording or documentary purposes, it is advisable to employ in such an endoscope, as the magnification varying element, either an ocular having two displaceable lenses, or a variable power lens system in place of one of said intermediate imageforming systems, since in these arrangements the magnifying power can be changed without changing the position of the exit pupil. Some variable power optical systems which may be used to replace one of said intermediate image-forming systems have more than two displaceable lenses.

It is therefore an object of the invention to provide an en- BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: FIG. la represents the optical system'of an endoscope embodying the present invention having a displaceable ocular field lens wherein the ocular field lens is positioned to produce one of the magnifying powers obtainable in this system;

FIG. lb represents the optical system of the ocular of the embodiment of the present invention shown in FIG. la when the ocular field lens is so located as to produce the other magnifying power available in this system;

FIG. It represents the lenses of the ocular of FIGS. la and lb;

FIG. 2a represents the optical system 'of an endoscope embodying the present invention having an ocular of continuously variable magnifying power when the displaceable lenses of,the ocular are so positioned as to provide one of the magnifying powers available with this system;

FIG. 2b represents the ocular portion of the optical system of FIG. 2a when the displaceable lenses'of the ocular are so positioned as to provide a value of magnifying power different from that provided when the displaceable lenses are positioned as shown in FIG. 2a;

FIG. 20 represents the lenses of the ocular of FIGS. Ia and FIG. 3a represents the optical system of an endoscope embodying the present invention in which the intermediate image-forming system nearest the ocular is of continuously variable magnifying power;

FIG. 317 represents the ocular of FIG. 30 when the displaceable lenses thereof are so adjusted as to provide a value of magnification different from that provided when the displaceable lenses are positioned as shown in FIG. 3a;

FIG. 3c represents the ocular of FIG. 3a when the displaceable lenses thereof are so adjusted as to provide a value of magnification different from that provide when the displaceable lenses are positioned as shown in FIGS. 3a and 312;

FIG. 3d represents the lenses of the variable-power intermediate image-forming system of FIGS. 3a through 3:.

Several embodiments of the endoscope-of the present invention are illustrated in the accompanying drawings and the lenses of the variable power elements'thereof are specified in the following tables. The mechanical details of endoscopes, and the nonvariable parts of the optical systems thereof, are generally well-known in the prior art, as exemplified in U.S. Pat. Nos. 1,680,490, and 1,995,196, referred to hereinabove, and such mechanical details and nonvariable optical elements will not be described or shown in detail herein. Only that part of the optical system of each embodiment which provides variable magnifying power will be particularly described and specified in detail in the following tables.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1a and lb illustrate an endoscope optical system according to the present invention wherein the ocular field lens is positionable in two different positions to provide twovalues of magnification. The optical data for variable power lens system of this embodiment are given in table I, the headings of which refer to the correspondingly designated elements of FIG. lc.As shown in FIGS. la and 1b, the reference character a designates the distance between the surface of the field lens nearest the objective and the vertex on the image side of the last member of the intermediate image-forming systems. This system provides two different, predetermined magnifications which are related by the magnification factor 1.82.

FIGS. 2a and 2b illustrate an endoscope optical system according to the present invention wherein two optical elements of the ocular are continuously displaceable to correspondingly continuously vary the magnification of the svstem. The maenification factor relating to the magnifications available at the extremes of adjustment is 1.68. The optical data for the variable power lens system of this embodiment are given in table 2, the headings of which are referred to the correspondingly designated elements of FIG. 2c.

FIGS.3a through 30 illustrate an endoscope optical system according to the present invention wherein the change in magnification is effected by displacement of two optical elements of the intermediate image-forming system located nearest the ocular. In this system the magnification factor relating the available magnifications at the extremes of adjustment is 1.73. The optical data for the variable power lens system of this embodiment of the invention are given in table 3,the headings of which are referred to the correspondingly designated elements of of FIG. 3d. As illustrated in FIGS. 3a through 30, a designates the distance between the vertex on the image side of the second member of the intermediate image-forming system nearest the ocular and the intermediate image plane.

' The mean values of the variable distances apply to a 1:1

Magnification factor 1.82.

m, is the distance of the surface of the field lens on the side of the objective to the vertex on the image side of the last member of the intermediate imageproducing system.

sau-33324432 Magnification factor 1.73. I m; designates the:distance between the vertex on the image side of the second member of the intermediate image-producing system and the intermediate image plane.

The mean values of the variable distances apply to a 1:1 image.

It should be understood, of course, that the foregoing disclosure relates to only preferred embodiments of the invention and that it is intended to cover all changes and modifications of the examples of the invention herein chosen for the purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention set forth in the appended claims lclaim:

1. An endoscope including an intermediate image-forming optical system and an ocular optical system, said ocular optical system having variable magnifying power and being constructed according to the following table wherein all linear dimensions are given in millimeters, r through r represent the successive radii of curvature of the surfaces of the lens elements, commencing with the lens surface nearest the intermediate image-forming optical system, a, through a, representing the successive distances between the vertices of the lens surfaces measured along the axis of the ocular optical system, a, being the distance between the adjacent vertices of the most closely adjacent lenses of said systems, n denotes the index of refraction of the glasses of the lens elements, and vreprescnts the Abbe number of the glasses of the lens elements, the magnifications of said ocular optical system being related by a factor of 1.82, and the focal length j varying between 14.9 and 27.1 millimeters.

2. An endoscope including an intermediate image-forming optical system and an ocular optical system, said ocular optical system having variable magnifying power and being constructed according to the following table wherein all linear dimensions are given in millimeters, r through r represent the successive radii of curvature of the surfaces of the lense elements commencing with the lens surface nearest the interrnediate image-forming optical system, a, through a represent the successive distances between the vertices of the lens surfaces measured along the axis of the ocular optical system, a being the distance between the adjacent vertices of the most closely adjacent lenses of said systems, n denotes the index of retraction of the glasses of the lens elements, and v represents the Abbe number of the glasses of the lens elements the extreme magnifications of said ocular optical system being related by a factor of 1.68, and the focal lengthy varying between 9.86 and 16.53 millimeters.

3. An endoscope including an intermediate image-forming optical system and an ocular optical system, said intermediate image-forming optical system comprising a variable power system constructed according to the following table wherein all linear dimensions are given in millimeters, r, through r represent the successive radii of curvature of the surfaces of the lens elements commencing with the lens surface most remote from the eyepiece of the endoscope, a,, through a represent the successive distances between the vertices of the lens surfaces measured along the axis of the endoscope, a being the distance between the adjacent vertices of the lens of said variable magnifying power system which is most remote from the eyepiece of the endoscope and the lens most closely adjacent it, in the direction toward the objective, n denotes the index of refraction of the glasses of the lens elements, and v represents the Abbe number of the glasses of the lens elements, the extreme magnification factors of said variable power optical system being related by a factor of l.73.

Claims

1. An endoscope including an intermediate image-forming optical system and an ocular optical system, said ocular optical system having variable magnifying power and being constructed according to the following table n v ao 38.4-21.5 r1 infinity a1 3 1.519 64.0 r2 -14.45 a2 10.75-27.65 r3 +11.2 a33.8 1.610 59.2 r4 -13.13 a4 0.8 1.678 32.0 r5 infinity wherein all linear dimensions are given in millimeters, r1 through r5 represent the successive radii of curvature of the surfaces of the lens elements, commencing with the lens surface nearest the intermediate image-forming optical system, ao through a4 representing the successive distances between the vertices of the lens surfaces measured along the axis of the ocular optical system, ao being the distance between the adjacent vertices of the most closely adjacent lenses of said systems, n denotes the index of refraction of the glasses of the lens elements, and v represents the Abbe number of the glasses of the lens elements, the magnifications of said ocular optical system being related by a factor of 1.82, and the focal length f'' varying between 14.9 and 27.1 millimeters.

2. An endoscope including an intermediate image-forming optical system and an ocular optical system, said ocular optical system having variable magnifying power and being constructed according to the following table n v ao 30.95-20.53 r1 -25.93 a1 1.5 1.519 64.0 r2 Infinity a2 3.2-23.62 r3 Infinity a3 3 1.519 64.0 r4 -14.45 a416-6 r5 +11.2 a5 3.8 1.610 59.2r6 -13.13 a6 0.81.67832.0 r7 Infinity wherein all linear dimensions are given in millimeters, r1 through r7 represent the successive radii of curvature of the surfaces of the lens elements commencing with the lens surface nearest the inTermediate image-forming optical system, ao through a6 represent the successive distances between the vertices of the lens surfaces measured along the axis of the ocular optical system, ao being the distance between the adjacent vertices of the most closely adjacent lenses of said systems, n denotes the index of retraction of the glasses of the lens elements, and v represents the Abbe number of the glasses of the lens elements, the extreme magnifications of said ocular optical system being related by a factor of 1.68, and the focal length f'' varying between 9.86 and 16.53 millimeters.

3. An endoscope including an intermediate image-forming optical system and an ocular optical system, said intermediate image-forming optical system comprising a variable power system constructed according to the following table n v ao 12.66-31.66-56-66 r1 +74.42a1 2 1.618 50.8 r2 -9.7 a2 1.21.734 28.1 r3 -22.65 a3 54-60-54 r4 22.65 a4 1.2 1.734 28.1 r5 +9.7 a5 2 1.618 50.8 r6 -74.42 ab 58.32-33.32- 14.32 wherein all linear dimensions are given in millimeters, r1 through r6 represent the successive radii of curvature of the surfaces of the lens elements commencing with the lens surface most remote from the eyepiece of the endoscope, ao through ab represent the successive distances between the vertices of the lens surfaces measured along the axis of the endoscope, ao being the distance between the adjacent vertices of the lens of said variable magnifying power system which is most remote from the eyepiece of the endoscope and the lens most closely adjacent it, in the direction toward the objective, n denotes the index of refraction of the glasses of the lens elements, and v represents the Abbe number of the glasses of the lens elements, the extreme magnification factors of said variable power optical system being related by a factor of 1.73.