Patent Application
20220197008
The present invention is directed to treating ends of optical fibers and more particularly to treating ends and loading of optical fibers for use in endoscopes.
Optical fibers are used to transmit light, or other electromagnetic radiation, along its length. To cause efficient coupling of the radiation into and out of an optical fiber or a bundle of optical fibers, both end faces are typically finished with a glossy surface that is achieved by optical polishing. The end faces are then typically mounted flush, i.e., in planar alignment with an aperture of a device. The smooth surface is also beneficial as it eliminates sharp edges that are present on the tip of a roughly finished optical fiber. These sharp edges may negatively impact the usefulness of the fiber due to the mechanical sharpness of the tips. The sharp edges also make the tips more prone to being damaged during use. Illustratively, a progression of finer and finer grit optical abrasives are used with a lapping tool to reduce the surface roughness of the end face until it achieves a suitably smooth and shiny surface that is substantially flat and free of pits and/or scratches. This polishing is illustratively performed in a multistep process that requires a substantial amount of time. The result is a surface on the end face that, similar to a polished lens, allows a substantial amount of light to be emitted with only Fresnel losses. The polished end is then aligned so that it is mounted flush with an aperture. This method is quite costly and requires a substantial amount of time to perform the plurality of rounds of polishing and precision to flush mount the optical fiber end.
The conventional polishing and flush mounting technique has worked well for reusable endoscopes and/or other devices where the additional costs required for processing the optical fiber end can be supported by the selling price of the reusable endoscopes. However, for single-use endoscopes (or other single use devices), where cost is critically important, these solutions are not practical. More generally, the conventional, multistep polishing and flush mounting technique may prevent the manufacture and/or assembly of low-cost devices where it is desirous to use optical fibers. Thus, there is a need for a low-cost and efficient alternative for the polished ends of optical fibers for use with low cost and/or single use devices.
The noted disadvantages of the prior art are overcome by providing novel treated ends of optical fibers for use in an endoscope. The treated ends of optical fibers in accordance with embodiments of the invention enabled improved emission of light. Further, the various embodiments described herein may be accomplished using substantially fewer resources than conventional optical fiber polishing and flush mounting, thereby reducing the overall cost of components that utilize optical fibers prepared in accordance with the various illustrative embodiments herein.
Illustratively, a bundle of one or more optical fibers has a proximal end that is aligned with an illumination source. The illumination source provides light rays that are captured by the proximal end and transmitted through the optical fibers. The light rays are then emitted from the distal ends of the optical fibers through illumination apertures at the distal end. Illustratively, the distal ends of the optical fibers may be raw cut and then coated with an optical material to improve the emission of light rays therefrom. The ends may be polished and then coated with an optical material to improve the transmission of light rays and to achieve alignment with an endpoint. Further, by varying the amount of material on the distal ends of the optical fibers, the fibers, though different lengths, may be emitting their light from a common surface, planar or otherwise.
The above and further advantages of the present invention are described herein in connection with the accompanying figures in which like reference numerals indicate identical or functionally similar elements, of which:
Endoscopes are well known in the art. Exemplary endoscopes are described in U.S. Pat. No. 6,139,490, entitled Stereoscopic Endoscope with Virtual Reality Viewing, U.S. Pat. No. 5,980,453, entitled Endoscope with Low Distortion, U.S. Pat. No. 7,758,498, entitled Endoscope with Relief of Axial Loading, and U.S. Patent Publication No. 2012/0212813 entitled Maximizing Illumination Fiber in an Endoscope, the contents of each of which are hereby incorporated by reference.
As seen in
A plurality of illumination apertures 215 are provided on the distal end 125. The illumination apertures 215 are illustratively arranged in a predefined pattern. However, it should be noted that in accordance with alternative embodiments, the predefined pattern may vary from that shown and described herein in relation to
It should be noted that while the exemplary endoscope is being described in relation to an imaging aperture, a working channel and a plurality of illumination apertures, the principles of the present invention may be implemented in endoscopes having differing configurations. Therefore, the description of specific components and arrangement thereof should be taken as exemplary only.
Illustratively, the core 305 is made of glass or plastic and is clear so that light (or other electromagnetic radiation) will propagate through it. The core has an exemplary end surface 320 that may be used to capture or emit light, or other electromagnetic radiation, in accordance with illustrative embodiments of the present invention. As noted above, typically the end 320 is polished, often after it is loaded into the endoscope, using a multi-step polishing technique that takes a substantial amount of time and greatly increases the overall cost of finishing an optical fiber to achieve a polished surface aligned with the distal end of the endoscope. In accordance with illustrative embodiments of the present invention, a technique is described to treat the end 320 of the optical fiber core 305 to improve its optical collection or emission properties over those of a raw (i.e., not polished or treated) end and then to position it sub-flush to the end of the endoscope. More generally, the inventive concepts described herein may be utilized to improve performance of the optical fibers at the distal end of an exemplary endoscope while positioning them sub-flush to the distal end of such endoscope. It is expressly contemplated that the principles of the present invention may be utilized with either polished or non-polished fibers. Therefore, the description contained herein should be taken as exemplary only.
As will be appreciated by those skilled in the art, not all light rays 405 that impact with end 320 are captured by the optical core 305. Some percentage of light rays are reflected off the end 320 and are not captured. Conventional polishing techniques for end 320 works to enable a very low percentage of light rays being reflected. Similarly, a conventionally polished end ensures that the number of light rays that are reflected back into the optical core when light is emitted remains low.
Aligned with aperture 210 is a working channel 530 that may be used for access by instruments, fluids, or energy. Illumination apertures 215 are aligned with optical fibers 300 that are then aligned, at their proximal end 545, with a light source 535. The light source may have one or more cables 540 A,B that feed back to the base of the endoscope in accordance with illustrative embodiments of the present invention.
It should be noted that while optical fibers 300 are shown as a singular unit, in illustrative embodiments, the optical fibers will be spaced around the other components at the distal end of the endo scope. Therefore, the depiction of a single optical fiber, or a bundle of optical fibers being in full alignment should be taken as exemplary only. As the optical fibers of the optical fiber bundle may extend from a single point at the proximal end to a plurality of differing points at the distal end, the optical fibers may not be aligned in a co-planar manner. As described further below, by treating the distal ends 615 of the optical fibers with varying amounts of material 620, the light from the distal ends of the optical fibers may be made to emit from a substantially co-planar surface in nominal alignment with the other elements of the distal end, e.g., lens cover and/or working channel 530. It should be noted that while end 615 of optical fiber 300 is shown as jagged, implying a raw cut end, the principles of the present invention may be utilized with either raw cut ends or polished ends. Therefore, the illustration of a raw cut end 615 should be taken as exemplary only.
In one embodiment of the present invention, the amount of light captured or emitted is increased as compared to the use of raw end, while avoiding the time and expense of multiple rounds of polishing as required by conventional techniques. Further, even when using polished fibers, the time and expense of mounting them flush may be reduced by mounting them sub-flush and utilizing the techniques of the present invention.
The material used to coat the distal ends of the optical fibers may vary in thickness so that the material coating the distal ends is substantially planar and co-planar with the end of the outside tube 505 which defines the distal end of the endoscope 700. By varying the thickness of the material on the distal ends of the optical fibers, a substantially flat optical emission surface results.
Then, in optional step 815, one end of the optical fiber bundle is cut to generate a raw end surface. Illustratively, the raw end surface of the optical fiber bundle may be generated using any of a number of techniques, e.g., by cutting using a mechanical device, etc. The term cut should be construed broadly to include any method of terminating the end of the optical fiber bundle. Other than mechanical cutting, this may include, e.g., breaking, cleaving, laser cutting, chemical cutting, thermal cutting, etc. Subsequent to the initial cutting, further processing may also include grinding and polishing to any desired level of finish. Fibers may be processed individually or as a group in a bundle prior to arranging in a bundle where the ends are brought to a desired degree of alignment. This degree is variable and is allowed by the addition of the coating material.
In embodiments where the ends of the optical fiber bundle are polished, optional step 815 is not required. In such exemplary embodiments, the procedure may proceed from step 810 directly to step 820. In step 820, the optical fiber bundle is then arranged at the distal end of an exemplary endoscope. As noted above, the distal ends may be arranged in a predefined pattern at the distal end. Due to inexact method of cutting and the spatial arrangement of the optical fibers within the bundle, each individual optical fiber may have a slightly varying distance from the end of the endoscope.
In step 825, the end surface is coated with a material which extends from the distal end of the fiber to the distal end of the endoscope. Illustratively, the material is an epoxy, such as an optical adhesive used to bond or pot optical elements as is known to one skilled in the art. One example of such an optical adhesive is Norland Optical Adhesive 61. However, it should be noted that in accordance with illustrative embodiments of the present invention, the material may be a substance other than epoxy. Illustratively, any material that is transparent or translucent to the desired light wavelength range may be utilized. Therefore, the description of the use of an epoxy as the material to be utilized should be taken as exemplary only.
The procedure 800 then completes in step 830. Once procedure 800 has completed, the distal end of the optical fiber bundle has been coated. Additionally, other elements at the distal end may be coated with the same material to create a uniform surface on the distal end.
It should be noted that the various descriptions and embodiments described herein are exemplary only. While this description has been written in terms of certain materials, it should be noted that, in alternative embodiments, differing materials may be utilized. As such, the description of any specific materials should be taken as exemplary only. Further, while the description of the material being used to treat the ends of the optical fiber bundle is described as an epoxy, in alternative embodiments it is expressly contemplated that other materials may be utilized. Therefore, the description of the material being used as an epoxy should be taken as exemplary only.
The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/127,635, which was filed on Dec. 18, 2020, by Joseph N. Forkey et al. for SYSTEM AND METHOD FOR TREATING ENDS OF OPTICAL FIBERS FOR USE IN AN ENDOSCOPE, which is hereby incorporated by reference. This application is related to U.S. Provisional Patent Application No. 63/043,189, entitled SYSTEM AND METHOD FOR TREATING THE END OF AN OPTICAL FIBER BUNDLE TO REDUCE LIGHT REFLECTION, filed on Jun. 24, 2020, the contents of which are hereby incorporated by reference. This application is related to U.S. patent application Ser. No. 17/354,159, entitled SYSTEM AND METHOD FOR TREATING THE END OF AN OPTICAL FIBER BUNDLE TO REDUCE LIGHT REFLECTION, filed on Jun. 22, 2021, the contents of which are hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63127635 | Dec 2020 | US |
