CA1240304A - Endoscope - Google Patents

Abstract

ENDOSCOPE

Abstract:
An endoscope for image-observing or measuring an area filled with an opaque liquid is disclosed. The endoscope comprises an image fiber, a lens positioned at the leading end of the image fiber, a light guide arranged in parallel to the image fiber, a transparent fluid trans-port passage arranged in parallel to the image fiber and the light guide and having an outlet at the leading end thereof, a sheath enclosing the image fiber, lens, light guide and transparent fluid transport passage and a means for providing a field of vision at the leading end of the endoscope by a transparent fluid from the outlet of the transparent fluid transport passage. A means for stabiliz-ing the field of vision formed by the field of vision providing means is provided on the leading end portion of the sheath.

Description

Z~0304 1 This application is a divisional of application Serial No. 443,199 filed December 13, 1983.
this invention relates to an endoscope for image-observing or measuring an area-filled with an opaque liquid.
It has been known that an area filled with an opaque liquid such as a blood vessel or the internal wall of the heart of a living body may be observed by the use of an endoscope having a means for providing a field of vision by a trays--parent fluid.
Fig. 1 is a schematic view for explaining the principle of an endoscope, Fig. 2 it a view showing one example of the leading end portion owe conventional.endoscope with a transparent fluid flush means,.
Figs. 3 Andy are longitudinally sectional and end elevation Al views respectively, of a conventional ennui-scope Wyeth transparent balloon;
Fig. 5 is a view showing the observation operation of the internal wall of the heart of living body by the conventional endoscope with a transparent balloon;
Figs. 6 and 7 are views showing an unstable field of vision caused by the swaying of the transparent balloon at thy joint thereof in the conventional endoscope;
Figs. 8 and 9 are longitudinally sectional and end elevational.views, respectively, of the leading end port lion of the endoscope according to the first embodiment of the present invention;
Figs. lo and 11 are-views showing the operational modes of the endoscope of the first embodiment for observe in a flat object such as the internal wall of the heat of a living body and a narrow field such as that in a brood vessel, respectively;
Fig. 12 is a sectional view showing the expansion Rand contraction of the resilient hood in the endoscope according to first embodiment of the present invention.;
Figs. 13, 14 and 15 are side elevation Al, end Elena-tonal and longitudinally sectional views, respectively, of the leading end portion of the.endoscope according to the second embodiment ox the present invention;

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- 2 -1 Fig. 16 is a view showing the inflated condition of the transparent balloon on the endoscope shown in Fig. 13;
Fig. 17 is a longitudinally sectional view of the leading end portion of the endoscope according to the third embodiment of the present invention;
Fig. 18 is a view showing the inflated condition of the transparent balloon on the endoscope of Fig. 17:
Fig . 19 is a view of a modification of the Solon-Dracula portion in the embodiment shown in Fig, 17;
Fig. 20 is an explanative view of the endoscope with a transparent balloon according to the fourth embodiment of the present invention in which Fig. aye shows the Cowan-lion of the endoscope prior to inflation of the balloons thereof and Fig. 20(b~ shows the condition of the endoscope after inflation of the-balloons thereof; and Fig. 21 it a view showing one specific example of the fourth embodiment of the invention in which Fig. aye is a view showing how to fabricate the endoscope and Fig. 21(b~ is a view showing the endoscope after inflation of the two balloons thereof.' Fugue is a schematic view-showing the principle of such an endoscope. on Fig. 1, 1 denotes a tube or catheter to be inserted into a living body, 2 denotes a blood vessel within the living body and 3 denotes an image fiber.
Basically, the image fiber 3 is inserted into the catheter 1 and a transparent fluid is passed through the catheter 1 and it flushed into an observation area within the living - body whereby the internal conditions of the body can be observed through the image fiber.
Fig. 2 shows one example of the leading end portion of the conventional endoscope provided with a transparent fluid flush means as a means for providing a field of vision.
In Fig. 2, 3 denotes an image fiber for transmitting an image from the observation area to an optical system or measuring system not shown, 4 denotes light guide for transmitting illumination light from a light source not 12~03C)4

- 3 -1 shown to the observation area, 5 denotes a cylindrical lens set, 6 denotes a prism and 7, 8 denote advancing directions of transparent fluid and illumination light. The transparent material which may be a saline, is directly s flushed from an outlet 9 into a blood vessel of a living body, for example, to dispel the blood from the observation area, whereby a transparent field of vision is formed in the blood vessel and the internal conditions of the blood vessel can be observed.
In this conventional endoscope shown in Fig-. 2, however, since the field of vision must be maintained in a condition which is free of blood and is transparent by - continuously excluding the flow of blood, a constant flow of a great amount of transparent fluid, usually an amount substantially corresponding to the amount of fluid flow within the blood vessel, must continuously be supplied to the area during the observation operation. the endoscope adapted to be inserted into a living body for observation of the living body preferably has as small an outer diameter as possible. However, in the endoscope shown in Fig. 3, in order to supply the transparent fluid in a great amount as mentioned hereinabove, the outer diameter of the endoscope becomes of necessity rather large. In addition, the supply of the transparent fluid in a great amount also requires the use of a specific electrically driven power cylinder to increase the supplying pressure of the transparent fluid.
In order to supplement such defects of the convent tonal endoscope above stated, another type of endoscope having transparent balloon as a means for providing a field of vision at the leading end thereof has been pro-posed and has become conventionally known.
Figs. 3 and 4 show longitudinally sectional and end elevation Al views, respectively, of a conventional endow ; scope lo with a transparent balloon.
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1 In these Figures, pa denotes an image fiber, pa denotes a lens, pa denotes light guides, pa denotes a transparent fluid transport passage, pa denotes a fluid outlet, if denotes a transparent balloon and 12 denotes a sheath. The transparent balloon 11 is secured to the sheath 12 by adhesive and binding means (not shown). When the internal wall of the heart of a living body is observed, for example, by inserting the endoscope into the living body, a transparent fluid such as COY gas or a saline is passed through the transparent fluid transport passage pa and discharged through the fluid outlet pa to inflate the transparent balloon 11 at the leading end of the endoscope whereby a transparent field of vision IS
forehand within the inflated transparent balloon 11.
Fig. 5 shows a conventional endoscope with a trays-parent balloon being used for the observation of the inter-net wall of the heart of a living body. The transparent balloon 11 inflated with the transparent fluid provides a transparent area 14 in contact with the heart's internal wall 13 between the endoscope and the heart's internal wall 13 whereby opaque blood 15 is excluded from the obser-ration area to provide a field of vision for observation.
However, the above mentioned conventional endoscope with the transparent balloon has a small or insufficient support area for the large size of the transparent balloon 11 when inflated and, thus, has a low or insufficient support capacity for the balloon. For this reason, when the endoscope is inserted into a living body for the observation of the internal conditions of the living body, the inflated balloon 11 attached to the leading end of the endoscope sways at the joint between the endoscope body and balloon-when subjected to a variation in the feed pressure of the transparent fluid and/or the reaction force from the living body tissue to be observed. Thus, the conventional endoscope with the transparent balloon has the ' , aye 1 disadvantage that the yield of vision tends to ye unstable during the observation operation. This sway of the balloon becomes greater when the-thickness of balloon wall is made thinner in order to increase the transparency of the balloon.
Figs, 6 and 7 show examples of the unstable conditions of the field of vision caused by the swaying of the in-fluted balloon at the joint between the endoscope body and balloon during the observation operation when subjected to outer force as shown by the arrows.
. 10 Therefore, the principal object of the present in-mention into eliminate the disadvantages inherent in the conventional endoscopes for optically observing or measuring an observation area filled with an opaque.liquid.and to provide an improved.endoscope which can provide a stable field of vision with a minimum amount of transparent flute during the observation operation.
According to the present invention, an endogcope . for image-observing.or measuring an area filled with an opaque liquid comprises; an image fiber; a lens positioned at the leading end of said image fiber; a light guide arranged in parallel to said image fiber; a transparent fluid transport . passage arranged in parallel to said image fiber and light guide and having an outlet at the leading end thereof; a-sheath enclosing said image fiber, lens, light guide and transparent fluid transport passage;
and a means for providing a field of vision at said leading . end of said endoscope by the transparent fluid; and it is further characterized by a means for stabilizing said fiend of vision formed by the field of vision providing means which stabilizing means is provided on the leading end portion of said sheath.
In one preferred example of the invention, said field of vision providing means comprises a flush of said transparent fluid directly spouted out from said outlet of said transparent fluid transport passage into said ~2~0304 1 opaque liquid and said stabilizing means comprises an expandable hood surrounding said lens the outlet of said transparent fluid transport passage, the leading end of the light guide and the flush of the transparent fluid. By this arrangement the field of vision is obtained stably at the observation area by a relatively small amount of transparent fluid and as a result, a transport passage of a relatively small diameter may be used for the trays-parent fluid, and thus the outer diameter of the endoscope can also be reduced and, at the same time, any specific electrically driven power cylinder for supplying the transparent fluid can be eliminated.
In another preferred example of the invention, said field of vision providing means comprises a transparent balloon provided at the leading end of said-endosc~pe and is inflatable by said transparent fluid supplied from said passage and said stabilizing means comprises a balloon support formed by substantially cylindrical and resilient material and.providea at the leading end portion Go the endoscope encircling the portion which forms the joint . Tony the balloon and the endoscope body so as to support the balloon joint portion when the balloon is inflated or, alternatively a support balloon mounted on said sheath at the leading end portion of the endoscope behind said transparent balloon for supporting the backside of the same when said two balloons. are inflated. By such arrange-mints also, the field of vision is obtained stably with a minimum amount of the transparent fluid being required.
.. Many.other.advantages, features and additional objects of the present invention will become apparent to persons skilled in the art upon making reference to the following description and the accompanying drawings which show preferred embodiments of the present invention by way of illustrative example.

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: . - pa -1 Figs. 8 and 9 are cross-sectional and front elev~tional views of the leading end portion of the endoscope lob of the first embodiment of the invention, respectively. In these Figures, 3b denotes an image fiber, S 4b denotes a light guides doughnuts lens and 7b denotes transparent fluid transport passage These components are enclosed as a unit in a sheath 12b.
The leading end of the transparent fluid transport passage 7b is formed with an outlet 9b.. A resilient hood 16 is formed at the.~leading.end of the sheath 12b Asian integral extension of the sheath and encircles the leading ends of the passage 7b, lens Sub and light guide 4b.
: Figs.- 10 and 11 show the operation modes of the endoscope of the first embodiment for observing the inter-net conditions of a living body. Fig. 10 shows the operation mode of the endoscope for observing a flat object .

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at an area for observation such as the internal wall 13 of the heart or the like, for example. Fig. 11 shows the operation mode of the endoscope for observing the internal conditions of a living body in the direction opposite to the flow direction of the blood 15 in relatively large blood vessel 2 such as thefem~ralartery, for example.
The hood 16 holds the transparent fluid 17 such as a saline in a stable condition at a limited area to be observed excluding the blood therefrom to thereby provide the field of vision free of blood 15 with a small amount ox transparent flow as a whole. That is, the observation is made possible through the transparent area defined by the hood adjacent to the light guide 4b and lens Sub.
As shown in Fig. 12, the resilient hood 16 is expanded, as shown by reference character A, only when necessity arises, by inflating a balloon device 18 provided in the wall of the hood 18 and this hood may normally be kept in a deflated state as shown by reference character B.
Thus, when the endoscope is inserted into the blood vessel, 20 the hood 16 is contracted so that the endoscope can be easily inserted into the blood vessel and after the endow scope has been inserted into the blood vessel, the hood 16 is expanded whereby the observation area is easily formed.
With the above-mentioned construction and arrange-mint of the components of the endoscope of this first embodiment, a field of vision can be effectively formed in the observation area by the transparent fluid in a rota-lively small amount. As a result, the diameter of the transparent fluid transport passage can be reduced and i 30 thus, the outer diameter of the endoscope can also be reduced. Furthermore, as the reduced amount of the transparent fluid required a lower pressure for supplying the fluid, the endoscope can be operated by merely manipulating a manual cylinder for pushing the fluid (not shown) without the need of a specific electrically driven power cylinder.
Figs. 13, 14 and lo are side elevation Al, end elevation Al and longitudinally sectional views, respective-lye of the second embodiment of the invention. The , Jo aye endoscope lo of this second embodiment includes a sub-staunchly cylindrical, flexible and resilient balloon support. More specifically as shown in Fig . 13, the Russell-en leading end portion of the outer peripheral portion of the endoscope contiguous to a sheath 12c is substantially cylindrical and is divided into a plurality of resilient pieces 19 by a plurality of slits which extend axially and inwardly from the outer edge. The leading end portion of the outer periphery of the endoscope is formed of deform-able synthetic resin such as polyethylene or vinyl chloride or metal such as phosphor bronze. In Figs. 14 and 15, the same reference numerals, with the addition of sub-reference characters, denote the same components as those in the endoscope shown in Figs. 3 and 4. The transparent balloon tic is fitted in the sheath 12c and adhered to the sheath at the area 20. As more clearly shown in Fig. 16, when the balloon tic is inflated, the resilient pieces 19 are subjected to the force resulting from the inflation of the balloon and deform radially outwardly from the bases to the outer ends of the resilient pieces in the form of a petal whereby the inflated balloon can be supported adjacent to the joint 20 over a wide range defined by the inner area of all the resilient pieces.
Fig. 17 is a longitudinally sectional view of the third embodiment of the invention. The endoscope lo of this embodiment includes a substantially cylindrical, flexible and resilient balloon support 20 at the leading end portion of the endoscope. In Fig. 17, the same refer-once numerals, with addition of sub-reference characters, denote the same components as those in the embodiment shown in Fig. 15. Although, the end elevation Al view of the third embodiment is omitted, the light guide is arranged in the same manner as in the embodiment of Fig. 14. The leading end portion of the outer periphery - 35 of the endoscope which is contiguous to the sheath 12d is formed of extensible material such as natural rubber or urethane and provides the cylindrical support 20 which gradually decreases in wall thickness towards the leading edge. The balloon lid is fitted in and adhered to the interior of the sheath 12d in the same manner as described in connection with the balloon shown in Fig. 13, but is not confined at the leading portion of the sheath Dwight S a clearance formed by the gradual decrease in the wall thickness of the sheath. As more clearly shown in Fig. 18, wren the balloon lid is inflated, the inner purrer Of : the cylindrical support 20 is subjected to the force resulting from the inflation of the balloon and deforms to expand towards the leading end of the support whereby the transparent balloon can be supported adjacent to the joint thereof over a wide range defined by the inner area of the' cylindrical Support 20. The cylindrical support 20 may be in the form of a resilient cap 21, formed lo separately from the sheath 12d, as shown in Fig. 19.
With the above mentioned construction and arrange-mint of the components of the endosco~e with a transparent balloon of the second and third embodiments, since the flailed of vision is formed by inflating the transparent balloon with the minimum amount of transparent fluid, the outer diameter of the endoscope can be made relatively stall. Also, since the transparent balloon can be support-en in stabilized condition adjacent to the joint thereof - . over Audi range by the flexible and resilient support, '' 25 when the internal structure of a living body is observed by the use of the endoscope, the position of the inflated balloon will not readily change even when the balloon is subjected to variation in the extraction and feed pressure.
in the endoscope and/or the reaction force from the living body internal structure. Thus, a stable field of vision can be maintained during the observation operation.
Furthermore, when the transparent balloon deflates, since the support formed of the flexible and resilient member returns from the expanded condition to the initial con-'` 35 treated condition, the endoscope can be inserted into the interior of a living body to be observed without dip-faculty.
Figs. 20 and 21 show the fourth embodiment of the , )304 present invention. the endoscope lye of this embodiment includes a transparent balloon tie at the leading end of the endoscope as a field of vision providing means and a support balloon 21 on the sheath ye at the leading end:
S portion of the endoscope behind the balloon tie. Fig. 20(~) shows the balloons tie, 21 in their position prior to inflation. In the illustrated embodiment, the balloon tie is inflated by the transparent fluid from the leading end of the transparent fluid transport passage lo and the lo support balloon 21 is inflated by a bypass fluid from a bypass hole 22 opened to the passage ye.
Fig. 20(b) shows the balloons in their inflated position. the interiors of these balloons are maintained at the same pressure. In the inflated position of thy balloons as shown in Fig. 20(b), the balloons tie, 21 contact each other to prevent the transparent balloon from displacing That is, the support balloon 21 supports the back side of the balloonlle and prevents~heballoon tie from deforming when the balloons are inflated whereby the field of vision of the endoscope is maintained in a stable state.
Incidentally, it is preferable that separate fluid passages are provided for the two balloons and toe internal pressure of the support balloon is maintained hooks than that of the transparent balloon to give a higher rigidity to the support balloon. The two balloons, and particularly the support balloon, are preferably formed of natural rubber or the like so that the balloons can be made as thin as possible and inflated to a substantial degree.
one specific example of this fourth embodiment will be now described below referring to Fix. 21. A natural rubber cap having the thickness ox 0.03 mm is fitted on a stainless steel pipe 23 having an outer diameter of 2.7 mm and the cap is tied at the rear end and at an intermediate point of the cap by means of a string 24. The first bet-loon tie is formed by the cap portion positioned forwardly of the intermediate tied point of the cap and the support balloon 21 is formed by the cay portion between the inter-mediate tied point and the tied rear end of the cap lZ~0~4 hole 22 of 0.5 mm diameter is formed in the wall of the pipe 23 at the area where the support balloon 21 is positioned.
A syringe 24 is attached to the rear end of the pipe 23 and when air under pressure of about 0.3 kg/cm2 is introduced into the assembly, the first and support balloon tie, 21 are inflated as shown in Fig. 2l(b1. When the first balloon tie is pressed against a suitable wall, it is apparent that the deformation of the first-mentioned balloon controlled by the support balloon is smaller lo than that of the transparent balloon of the conventional endoscope which has no support balloon. In Fig. 21, the other dimensions are as follows. Lo = 12 mm, Lo = 6 mm, Lo = 3.5 mm, Lo = 4 mm, Lo = about lo mm, Lo = about 5 mm, Do 2.7 mm and Do = about 12 mm.
}S With the above mentioned construction and arrange-mint of the components of the endoscope of the fourth embodiment, the outer diameter of the endoscope can be made relatively small due to the same reasons stated in conjunction with the second and third embodiments. Also, yin this fourth embodiment, since the support balloon provides the same pushing effect as that which would be provide by a semi-rigid plate if such a plate were provided behind the first balloon to prevent the displace-mint of the deformation of the first balloon, the field of vision is made stable and the first balloon can be made a inn and transparent as possible.
Further, in this fourth embodiment, since a support member can be provided on the endoscope without sub Stan-tidally increasing the diameter of the latter, the endoscope can be quite easily inserted into the living body.
In the foregoing, although description has been made of the application of the endoscope of the invention to the observation of the internal structure of a living body, the endoscope can be also applied to a wide range of fields including various industrial and optical observation devices which provide a field of vision in an observation area filled with an opaque liquid.

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Claims (5)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An endoscope for image-observing or measuring an area filled with an opaque liquid comprising:
an image fiber;
a lens positioned at the leading end of said image fiber;
a light guide arranged in parallel to said image fiber;
a transparent fluid transport passage arranged in parallel to said image fiber and light guide and having an outlet at the leading end thereof;
and a sheath enclosing said image fiber, lens, light guide and transparent fluid transport passage wherein a field of vision is provided at the leading end of said endoscope by a flush of the transparent fluid directly spouted out from said outlet of said transparent fluid transport passage into said opaque liquid; characterized in that a means for stabilizing said field of vision formed by said flush of the transparent fluid is provided on the leading end portion of said sheath,said stabilizing means comprises an expandable hood surrounding said lens, the leading end of said light guide, the opening of said transparent fluid transport passage and said flush of the transparent fluid.

2. The endoscope as set forth in claim 1, in which said hood forms an extension of said sheath at the leading end of said endoscope.

3. The endoscope as set forth in claim 1, in which said hood is formed of a resilient material and includes a balloon device in the wall of said hood.

4. The endoscope as set forth in claim 3, in which said resilient material is rubber.

5. The endoscope as set forth in claim 1, 2 or 3 in which said opaque liquid is blood and said endoscope is one used for observing a blood vessel or the internal wall of the heart of a living body.