Surgery – Endoscope – Having imaging and illumination means
Reexamination Certificate
2000-04-01
2003-01-07
Dvorak, Linda C. M. (Department: 3739)
Surgery
Endoscope
Having imaging and illumination means
C600S130000, C600S177000, C600S129000
Reexamination Certificate
active
06503196
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an endoscope having a head at the proximal end; having an outer tube joined to the head; having an inner tube, received in the outer tube, in which optical components are received, a window made of transparent material being arranged at the distal end of the inner tube; and having light guides that are received in an interstice between inner tube and outer tube and are guided axially to the distal end of the interstice.
An endoscope of this kind is marketed by the Applicant.
FIG. 12
of the appended drawings shows a longitudinal section through a distal end segment of an endoscope of this kind according to the existing art.
An inner tube R is received in outer tube A, which is permanently joined to the head of the endoscope. Inner tube R contains optical components, for example a lens arrangement, in particular a rod lens arrangement (called a “Hopkins optical system”), with which an image entering the inner tube at the distal end is guided to the proximal end of the endoscope. An eyepiece cup, against which an eye can be placed, is usually mounted at the proximal end of the endoscope.
In other configurations the optical components contain, for example, so-called optoelectronic charge-coupled device (CCD) sensors in the form of microchips, which convert the incoming image data into electrical signals that are sent in the proximal direction via electrical lines; after image processing, the image is displayed on a monitor.
The configuration of the head depends on the manner in which the image is viewed, i.e. either visually or by way of electronic image recording and playback, and the head can be simply a proximal end of a tubular element to which a camera module can be connected.
Since the optical elements in inner tube R constitute sensitive components, the distal end of the inner tube is closed off in hermetically sealed fashion by way of a window F. This closure is accomplished by the fact that a disk made of transparent material, usually a glass disk, is inserted into the open distal end of inner tube R and is joined sealedly and permanently to the inner side of the end segment of inner tube R, for example by soldering or adhesive bonding. In an interstice between the outer side of inner tube R and the inner side of the lager-diameter outer tube A, light guides in the form of glass fibers are guided from a proximal, usually laterally protruding, light connector to the outermost distal end of the endoscope, i.e. to the outermost distal end of the outer tube or inner tube, which end at the same level. The outermost distal ends of the glass fibers thus lie in the plane of the distally outer surface of disk F.
The individual glass fibers are cemented at the distal end to one another, and to the outer side of inner tube R and to the inner side of outer tube A.
The interior space of the endoscope is thus divided, in principle, into the interior space of inner tube R hermetically closed off toward the outside by window F, and the interstice between inner tube R and outer tube A in which light guides L are received, this space being closed off by the cemented join of the individual glass fibers to one another and the cemented join to the outer side of the inner tube and to the inner side of outer tube A.
This basic principle is also realized in those endoscopes whose interior space has not only these spaces (interior space of inner tube R, interstice) but also further spaces or ducts, for example for the passage of instruments or to form flushing or venting ducts. One such endoscope is known, for example, from U.S. Pat. No. 4,361,139. In addition to the inner tube, hermetically closed off by the distal-end window, in which the optical components are received, and an interstice in which the glass fibers are received, further ducts or spaces are also present. Here again, the light guides are guided to the distal end at the level of the outer plane of the window that seals the inner tube.
For reasons of sealing and stability, the inner tube is also joined to the head of the endoscope; the result of this is that the inner tube and the outer tube are joined at the proximal end via the head of the endoscope, and at the distal end via the cemented join.
Because of the widespread use of endoscopes in minimally invasive surgery, endoscopes of this kind are in frequent use and must be frequently cleaned or autoclaved. Such sterilization or autoclaving operations are performed in a temperature range from 130 to 140° C. In order to make endoscopes available again as quickly as possible after a procedure, so-called “flash” autoclaving techniques have been developed, in which the entire endoscope is heated to 143° C. and then quenched with cold water.
In view of the occurrence of pathogens that can withstand extremely high temperatures (one example being the so-called BSE pathogen), endoscopes must be exposed to extremely high temperatures.
It has now been found that the cemented points at the distal glass fiber end cannot withstand these severe stresses over the long term, and it is possible for leaks to occur which allow the penetration of contaminants or autoclaving media. The optical illumination system is disadvantageously influenced thereby, i.e. its illumination capability is weakened. The cemented points, which comprise a cured plastic material, can contain micropores which gradually can be penetrated by the media to which the distal end of the endoscope is exposed, so that bacterial pockets also exist.
The temperature fluctuations taking place during the autoclaving operations, in particular in flash autoclaving operations, cause considerable longitudinal mechanical stresses between the inner and the outer tubes which can result in breakage of the joins, in particular the joins between the cement and the outer side of the inner tube or the inner side of the outer tube in the region of the distal end, so that contaminants may then be able to penetrate over a large area and the endoscope thus becomes unusable.
DE 195 25 995 C1 discloses an endoscope whose distal end is closed off by a window. This window covers the entire end segment, i.e. both the region from which the light coming from the light guides emerges from the endoscope, and the distal end region of the inner tube in which the optical components are received. To prevent any coupling of light from the light guides into the optical system carrying the image, provision is made for at least one groove, extending parallel to the parting line between the cross-sectional regions of the image guide and the light guide and installed in one of the parallel surfaces of the window panel, to be provided as a light stop. The side surfaces or side flanks of the groove are intended either to reflect back or otherwise to prevent the crossover of light rays reflected transversely through from the light guide to the image guide.
Cross-reflection can thereby be considerably decreased but not eliminated, since the groove depth, weighed against the remaining mechanical strength of the window panel, determines the degree to which reflection is suppressed.
It is disadvantageous in this context that light spillover from the illumination system into the image-carrying system in the transverse direction cannot be completely eliminated, and that the grooves cause weakening of the mechanical stability of the one-piece window panel. This window panel cannot withstand the severe mechanical stresses occurring, for example, during handling, in particular during cleaning and sterilization, or those resulting from a fall.
DE 42 11 542 C2 discloses a protective cover for the distal end of the endoscopes that has a first component which has a mount that can be placed onto the end of the inner tube which receives the optical components. The mount itself carries centeredly a window with an optical effect, through which light can enter the optical system from the outside.
At the distal end the window projects beyond the mount, and a second part which covers the remaining end surface of the distal end of t
Irion Klaus M.
Kehr Ulrich
Rudischhauser Jürgen
Dvorak Linda C. M.
Karl Storz GmbH & Co. KG
Ram Jocelyn
St. Onge Steward Johnston & Reens LLC
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