Abstract:
A fiber optic illumination device suitable for use in medical procedures and other application requiring the delivery of light to limited access locations is disclosed. The illumination device defines a proximal terminal structure derived from the optical fiber having a greater surface area than the diameter of the optical fiber and a distal terminal structure derived from the optical fiber having a greater surface area than diameter of the optical fiber. An integral light communication path is defined between the proximal terminal structure and the distal terminal structure. A method of manufacturing the fiber optic illumination device is also disclosed.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to an improved fiber optic illumination device that attaches to a light source and is used to precisely deliver an increased level of light to limited accessibility surgical sites. The invention can also be used for other medical and non-medical applications requiring illumination of limited access areas. 
       BACKGROUND 
       [0002]    The use of optic fibers or groups of optical fibers attached to different types of light sources to illuminate areas having limited accessibility and lacking a clear line of sight with an external light source is well known in the art. Use in medical applications is sometimes limited by the buildup of excess temperature at the distal or light emitting end of the optical fiber. This is at least partly due to the inherent inefficiency of typical optical fibers to deliver light at specific target areas and the increased emission of light from the attached light source required to provide adequate illumination to a surgical site. 
         [0003]    At the proximal end of the optical fiber, current fiber optic illumination systems require an optical fiber with a relatively large diameter and/or a relatively large Numerical Aperture to collect an adequate amount of the typically highly divergent light from an attached light source. 
         [0004]    Further, at the distal end, current fiber optic illumination systems suffer from excess light scattered outside the target area due to an inability to emit the high order mode light collected at the proximal end and distribute it at the distal end as low order mode light. Existing fiber optic illumination systems require a relatively large diameter fiber to deliver similar light intensities on a relatively small target area. 
         [0005]    What is clearly needed, therefore, is a fiber optic illumination system allowing a relatively small diameter optical fiber to collect high order mode light at the proximal end, transmit the light along the length of the optical fiber, and distribute lower order mode light at the distal end. 
       SUMMARY 
       [0006]    In one embodiment, the invention is directed to an illumination device having an optical fiber defining a proximal end, a distal end, a length, a core fiber layer and a cladding layer surrounding at least part of the core fiber layer. A connector is attached to the proximal end of the optical fiber and defines a proximal end and a distal end, with the optical fiber extending into the connector. At the distal end of the optical fiber is a distal tube into which the optical fiber extends. The proximal end of the optical fiber is configured into a proximal terminal structure derived from the optical fiber, which causes high order mode light entering the illumination device to be converted to low order mode light and the distal end of the optical fiber is configured into a distal terminal structure derived from the optical fiber, which causes high order mode light to be converted into low order mode light emitted from the illumination device. The proximal distal structure, distal terminal structure and at least the fiber core are integral with each other. 
         [0007]    In another embodiment, the invention is directed to an illumination device having an optical fiber defining a proximal end, a distal end, a length, a diameter, a core fiber layer and a cladding layer surrounding at least part of the core fiber layer. A connector is attached to the proximal end of the optical fiber and defines a proximal end, a distal end, and a channel extending into the connector, with the channel defining a diameter. A crimp sleeve surrounds a portion of the optical fiber and is secured over the outer dimension of the optical fiber by crimping the crimp sleeve. Surrounding a portion of the crimp sleeve is a proximal strain relief member, with the proximal strain relief member being secured to the outer diameter of the channel extending through the connector. A distal tube is attached to the distal end of the optical fiber and defines a distal end and is configured to receive the optical fiber. The proximal end of the optical fiber is configured into a proximal terminal structure derived from the optical fiber having a greater surface area than the diameter of the optical fiber which causes high order mode light entering the illumination device to be converted to low order mode light and the distal end of the optical fiber is configured into a distal terminal structure having a greater surface area than the diameter of the optical fiber and causes high order mode light to be converted into low order mode light which is emitted from the illumination device. The proximal terminal structure, distal terminal structure and core fiber are integral with each other. 
         [0008]    In an alternative embodiment, the invention is directed to a method of manufacturing a fiber optic illumination device, including the steps of: 
         [0009]    a. preparing a proximal section of the illumination device by:
       i. providing an optical fiber defining a proximal end, a distal end, an outer diameter, a length, a cladding layer and a core layer;   ii. trimming the proximal end and the distal end of the optical fiber;   iii. sliding a length of crimp sleeve over the proximal end of the optical fiber, allowing a length of optical fiber to extend from the proximal end of the crimp sleeve;   iv. crimping the crimp sleeve with sufficient mechanical force to cause the crimp sleeve to take a permanent set to secure the crimp sleeve to the optical fiber without damaging the optical fiber;   v. providing a connector defining a proximal end, a distal end and a channel extending there through;   vi. inserting and attaching a proximal strain relief member into the distal end of the channel in a manner allowing a portion of the proximal strain relief member to extend distally from the connector;   vii. fitting the optical fiber with attached crimp sleeve into the connector through the proximal strain relief member to allow a length of optical fiber to extend from the proximal end of the connector;   viii. exposing the end of the optical fiber extending from the proximal end of the connector to a sufficient amount of air and heat to cause the proximal end of the optical fiber to reflow, creating a first structure extending from the proximal end of the connector having a diameter wider than the optical fiber prior to reflowing; and       
 
         [0018]    b. preparing a distal end of the illumination device by:
       i. providing a distal tube;   ii. sliding the distal tube over the optical fiber allowing a length of optical fiber to extend from the distal end of the distal tube;   iii. crimping the distal tube with sufficient mechanical force to cause the crimp sleeve to take a permanent set to secure the crimp sleeve to the optical fiber without damaging the optical fiber; and   iv. exposing the end of the optical fiber extending from the distal end of the distal tube with a sufficient amount of air and heat to cause the proximal end of the optical fiber to reflow, creating a second structure extending from the distal end of the connector having a diameter wider than the optical fiber prior to reflowing, resulting in a fiber optic illumination device with an integral light communication path between the proximal end of the illumination device and the distal end of the illumination device.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a plan view of the fiber optic illumination device of the invention. 
           [0024]      FIG. 2   a  is a lateral cross section taken through lines  2   a - 2   a  of  FIG. 1 . 
           [0025]      FIG. 2   b  is a lateral cross section taken through lines  2   b - 2   b  of  FIG. 1 . 
           [0026]      FIG. 3  is a longitudinal cross section taken through the connector. 
           [0027]      FIG. 4   a  is a longitudinal cross section taken through the proximal section of an alternative embodiment of the invention. 
           [0028]      FIG. 4   b  is a longitudinal cross section taken through the distal section of an alternative embodiment of the invention. 
           [0029]      FIG. 5   a  is a longitudinal cross section taken through the proximal section of another embodiment of the invention. 
           [0030]      FIG. 5   b  is a longitudinal cross section taken through the distal section of another embodiment of the invention. 
           [0031]      FIG. 6  is a flowchart illustrating the steps of the method of manufacturing. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    The particulars shown herein are by way of example and for purposes of illustrative discussion of the invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. The drawings are in simplified form and are not to precise scale. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for the fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. Wherever possible, same or similar reference numerals are used in the drawings to refer to the same or like parts or steps. 
       NOMENCLATURE  
       [0000]    
       
           10  Fiber Optic Illumination Device 
           10   a  Proximal Section of Fiber Optic Illumination Device 
           10   b  Distal Section of Fiber Optic Illumination Device 
           12  Connector 
           12   a  Proximal End of Connector 
           12   b  Distal End of Connector 
           12   c  Connector Channel 
           14  Proximal Strain Relief Member 
           16  Optical Fiber 
           16   a  Proximal End of Optical Fiber 
           16   b  Distal End of Optical Fiber 
           18  Distal Tube 
           18   a  Bend in Distal Tube 
           18   b  Crimp 
           18   c  Distal End of Distal Tube 
           20  Cladding 
           22  Crimp Sleeve 
           22   a  Proximal End of Crimp Sleeve 
           22   b  Distal End of Crimp Sleeve 
           24  Optical Fiber Core 
           24   a  Proximal End of Optical Fiber Core 
           24   b  Distal End of Optical Fiber Core 
           26   a  Proximal Terminal Structure 
           26   b  Distal Terminal Structure 
           50  Providing Optical Fiber 
           52  Trim Proximal End and Distal End of Optical Fiber 
           54  Slide Crimp Sleeve Over Distal End of Optical Fiber with Length of Optical Fiber Proximally Extending 
           56  Crimping Crimp Sleeve to Optical Fiber 
           58  Provide Connector 
           60  Insert and Attach Proximal Strain Relief Member to Connector 
           62  Fit Optical Fiber/Crimp Sleeve through Proximal Strain Relief Member and Connector so 
           64  Expose Proximally Extending Optical Fiber to Sufficient Heat to Reflow Length of Optical Fiber Proximally Extending from Connector 
           66  Provide Distal Tube 
           68  Slide Distal Tube over Optical Fiber Allowing Length of Optical Fiber to Distally Extend 
           70  Crimp Distal Tube to Secure to Optical Fiber 
           72  Expose Distally Extending Optical Fiber to Sufficient Heat to Reflow Length of Optical Fiber Distally Extending from Distal Tube 
           112  Connector 
           112   a  Proximal End of Connector 
           112   b  Distal End of Connector 
           112   c  Connector Channel 
           112   d  Concavity 
           118  Distal Tube 
           118   c  Distal End of Distal Tube 
           118   d  Concavity 
           124   b  Distal End of Optical Fiber Core 
           126   a  Proximal Terminal Structure 
           126   b  Distal Terminal Structure 
           212  Concavity 
           212   a  Proximal End of Channel 
           212   c  Channel 
           212   d  Concavity 
           218  Distal Tube 
           218   c  Distal End of Distal Tube 
           218   d  Concavity 
           224   b  Distal End of Optical Fiber Core 
           226   a  Proximal Terminal Structure 
           226   b  Distal Terminal Structure 
       
     
       Definitions 
       [0090]    “Distal” means further from the point controlled by the operator (e.g., physician or technician) of a device. 
         [0091]    “Glass Optical Fiber” means an optical fiber that is comprised of one or more hard, amorphous or crystalline materials. This generally not pure “glass” in the technical sense but rather one or more multiple varieties of fused silica, doped fused silica or other materials such as sapphire and similar materials. Glass Optical Fiber may also refer to optical fibers having a “glass” core (with respect to the description above) and polymer cladding layer(s). 
         [0092]    “High Order Mode Light” means light that enters an optical fiber at a relatively high transverse path to the longitudinal axis of the optical fiber. High order mode light can be so transverse as to be greater than the critical angle and therefore penetrate the interface between the core and cladding and be permanently lost through the cladding. 
         [0093]    “Lateral Cross Section” means a cross section taken through a substantially perpendicular angle to the length of an object. 
         [0094]    “Longitudinal Cross Section” means a cross section taken through a substantially parallel angle to the length of an object. 
         [0095]    “Low Order Mode Light” means light that enters an optical fiber at an angle either parallel to or relatively modestly transverse to the longitudinal axis of the optical fiber. 
         [0096]    “Numerical Aperture” (NA) means The light-gathering ability of an optical fiber, as determined by the square root of the difference of the squares of the refractive indexes of the core (n 1) and the cladding (n 2), and as expressed in the equation: NA=(n 1 2−n 2 2)½. Fiber optic transmission systems (FOTS) are based on the principle of total internal reflection, meaning that all light injected into the fiber is retained in the fiber. The objective is to retain all components of the optical signal in the core. However, a light source naturally injects some light rays into the core at angles greater than the critical angle, which is parallel with the longitudinal axis of the optical fiber core. At such severe angles, the incident light rays penetrate the core/clad interface and enter the cladding, where they will be lost. The numerical aperture essentially is an indication of how wide an angle of incident light will be captured and propagated by the optical fiber. For example, an optical fiber with a small NA requires more directional, focused, light, whereas a fiber with a large NA does not. The higher NA allows the fiber to accept more light at a greater angle relative to the fiber&#39;s longitudinal axis and thus propagate higher modes. 
         [0097]    “Plastic Optical Fiber” means an optical fiber made out of polymeric materials, with the core often being a polymer such as an acrylic material and the cladding being a polymer being a polymer with a lower refractive index such as fluorinated polymers. 
         [0098]    “Proximal” means closer to the point controlled by the operator (e.g., physician or technician) of a device. 
         [0099]    “Reflow” means applying sufficient pressure and/or temperature to a polymeric material to cause it to change configuration. 
         [0100]    “SCFM” means standard cubic feet per minute. SCFM is the volumetric flow of a gas corrected to “standardized” conditions of temperature and pressure. It is understood that there is no universally accepted set of standardized conditions. 
         [0101]    “Terminal Structure” as used herein means a structure integral with at least the fiber core configured to have a greater surface area than the diameter of the fiber core. 
         [0102]    “Tg” means glass transition in glass forming materials characterized by a change in phase from solid to liquid upon the application of heat. 
       Construction 
       [0103]      FIG. 1  shows a plan view of the fiber optic illumination device  10  of the present invention. It is seen that a connector  12  is attached proximate to the proximal end  24   a  of an optical fiber  16  and defines a proximal end  12   a  and a distal end  12   b  and a channel  12   c  extending the length of the connector  12 . The connector  12  is of conventional design and is used to attach the fiber optic illumination device  10  to an external light source (not shown). The optical fiber  16  extends through and from a proximal strain relief member  14 , which is attached to and extends distally from the distal end  12   b  of the connector  12  and provides support and protection for the optical fiber  16  during use. Both plastic optical fiber material and glass optical fiber material are suitable to be used when practicing the present invention. Proximal strain relief member  14  can be made of any suitable thermoplastic tubing such as Tygon®, nylon, PTFE, silicone, polyurethane, braided tubing or any other material possessing suitable physical and biocompatible properties and serves to generally support, protect and more specifically prevent the optical fiber  16  from kinking during use. The connector  12  and proximal strain relief member  14  are attached to each other by any of several chemical and/or mechanical means including but not limited to interference fitting, gluing, crimping and thermal attachment. In one embodiment, the outer diameter of the proximal strain relief member  14  is greater than the inner diameter of the channel  12   c  extending longitudinally through the channel  12   c  of connector  12  resulting in an interference fit attachment. 
         [0104]    In one embodiment, optical fiber  16  and connector  12  are fitted together using a crimp sleeve  22  which is crimped over the outer surface (cladding  20 ) of the optical fiber  16 . In one embodiment the crimp sleeve  22  is made of stainless steel hypotube and in another embodiment aluminum hypotube, however, the crimp sleeve  22  can also be made of additional materials possessing adequate strength and mechanical characteristics. The optical fiber  16  with attached crimp sleeve  22  is inserted into the channel  12   c  which extends longitudinally through the connector  12  which, as described above has had previously attached a proximal strain relief member  14 . The optical fiber  16  is attached to the connector  12  by means of treating the extending proximal end  16   a  of the optical fiber  16  with a sufficient amount of heat and air to cause the distal end  16   a  to reflow. In one embodiment, air having an approximate temperature between 400 degrees F. and 500 degrees F. at an airflow of approximately 5-20 standard cubic feet per minute for a period of approximately 2-5 seconds reaches the Tg of the base material causing the proximal end  16   a  of the optical fiber  16  to reach a reflow state, resulting in the simultaneous melting of the core  24   a  and cladding  20  and the formation of a proximal terminal structure  26   a  integral with the core  24 . The formation of the proximal terminal structure  26   a  serves to secure the optical fiber  16  to the connector  12  without the use of chemical or mechanical fasteners and also provides a structure similar to a lens, which is integral with at least the core  24  along the length of the fiber optic illumination device  10 . It is noted that due to the extra dimension inherent in the convex proximal terminal structure  26   a,  a greater surface area is exposed than the diameter of the optical fiber  16  would have if squarely trimmed. 
         [0105]    Toward the distal end  16   b  of the optical fiber  16  is a distal tube  18  through which the optical fiber  16  passes and which serves to provide shape, strength and stability to the fiber optic illumination device  10  during use when it is normally securely attached to a surgical retractor or other surgical hardware during a procedure. In one embodiment the distal tube  18  is made of stainless steel and in another embodiment, aluminum, however, the distal tube  18  can also be made of additional materials possessing adequate strength and formability. It is noted that in one embodiment, the distal tube  18  is crimped  18   b  to the cladding  20  defining the outer surface of the optical fiber  16 . In one embodiment, the optical fiber  16  is attached to the distal end  18   c  of the distal tube  18  by means of treating the optical fiber  16  with a sufficient amount of heat and air to cause the distal end  16   b  of the optical fiber  16  to reflow. Air having an approximate temperature between 400 degrees F. and 500 degrees F. at an airflow of approximately 5-20 standard cubic feet per minute for a period of approximately 2-5 seconds reaches the Tg of the base material causing the distal end  16   b  of the optical fiber  16  to approach the reflow state, resulting in the simultaneous expansion of the core  24  and cladding  20  and the formation of a distal terminal structure  26   b.  The formation of the distal terminal structure  26   b  serves to secure the optical fiber  16  within the distal tube  18  without the use of chemical or mechanical fasteners and also provides a structure similar to a lens, but which is integral with at least the core  24  along the length of the fiber optic illumination device  10  between the proximal terminal structure  26   a  and the distal terminal structure  26   b,  allowing uninterrupted light communication between the proximal terminal structure  26   a  and distal terminal structure  26   b.  It is noted that due to the extra dimension inherent in the convex proximal terminal structure  26   b,  a greater surface area is exposed than the diameter of the optical fiber  16  would have if squarely trimmed. It is understood that the distal tube  18  shown in  FIG. 1  can be pre-formed into any shape required by the particular retractor or surgical hardware used as well as the preferences of the surgeon performing the procedure and should therefore not be considered as being limited to the particular shape shown. It is also understood that the distal tube  18  could be made of a malleable material able to be quickly shaped into any shape desired. 
         [0106]      FIG. 2   a  is a lateral cross section taken through the lines  2   a - 2   a  of  FIG. 1 . It is seen that the optical fiber  16  is surrounded at least part of the length (unnumbered) of the connector  12  by the crimp sleeve  22  which in turn is surrounded by the proximal strain relief member  14  which is attached to and extends from the distal end  12   b  of the connector  12 . 
         [0107]      FIG. 2   b  is a lateral cross section taken through the lines  2   b - 2   b  of  FIG. 1 . It is seen that the core  24  is surrounded by the cladding  20 , which is surrounded by the distal tube  18 . A crimp  18   b  is impressed into the distal tube  18  which serves to stabilize and secure the optical fiber  16  within the illumination device  10 . While a certain number of crimps  18   b  are impressed into the distal tube  18  it is understood that this is for purposes of illustration only and that lesser or greater numbers of crimps  18   b  as well as different configurations (i.e., at different positions on the distal tube  18 ) are within the scope of the invention. 
         [0108]      FIG. 3  is a longitudinal cross section taken through the connector  12 . It is seen that at least the core  24  extends the length (unnumbered) of the connector  12 , allowing an integral light path along the length of the fiber optic illumination device  10  of the present invention. 
         [0109]      FIG. 4   a  shows an alternative embodiment of the proximal terminal structure  126   a  wherein the optical fiber  16  fits in a beveled concavity  112   d  at the proximal end  112   a  of the channel  112   c.  It is noted that the exposed end (unnumbered) of the proximal terminal structure is flush with the proximal end  112   a  of the connector  112  and thus presents a greater surface area than the diameter of the optical fiber  16  would have if squarely trimmed. 
         [0110]      FIG. 4   b  similarly shows an alternative embodiment of the distal terminal structure  126   b  wherein the optical fiber  16  ends at a beveled concavity  118   d  at the distal end  118   c  of the distal tube  118 . It is noted that the exposed end (unnumbered) of the distal terminal structure  126   b  is flush with the distal end  118   c  of the distal tube  118  and thus presents a greater surface area than the diameter of the optical fiber  16  would have if squarely trimmed. While the distal terminal structure  126   b  is shown as being flush with the distal end  118   c  of the distal tube  118 , this is for purposes of illustration only and it is understood that other configurations such as, but not limited to, angled, multifaceted or recessed configurations not extending to the distal end  118   c  are also within the scope of the invention. 
         [0111]      FIG. 5   a  shows an another embodiment of the proximal terminal structure  226   a  wherein the optical fiber  16  fits in a beveled concavity  212   d  at the proximal end  212   a  of the channel  212   c.  It is noted that the exposed end (unnumbered) of the proximal terminal structure is concave and extends longitudinally into the proximal end  212   a  of the connector  212  and thus presents a greater surface area than the diameter of the optical fiber  16  would have if squarely trimmed. 
         [0112]      FIG. 5   b  similarly shows an another embodiment of the distal terminal structure  226   b  wherein the optical fiber  16  ends at a beveled concavity  218   d  at the distal end  218   c  of the distal tube  218 . It is noted that the exposed end (unnumbered) of the distal terminal structure  226   b  is concave and extends longitudinally into the distal end  218   c  of the distal tube  218  and thus presents a greater surface area than diameter of the optical fiber  16  would have if squarely trimmed. While the distal terminal structure  226   b  is shown as being recessed within the distal end  218   c  of the distal tube  218 , this is for purposes of illustration only and it is understood that other configurations such as, but not limited to, configurations wherein the optical fiber  16  having a concave distal terminal structure  226   b  extending from the distal end  218   c  (not shown) are also within the scope of the invention. 
         [0113]    It is known that the present claimed invention is able to deliver light along its length with much greater efficiency than currently existing fiber optic illumination systems, allowing an increased amount of light to be delivered from the distal end  24   b,    124   b,    224   b  of the optical fiber  16  which is collected from a lower powered light source. It is believed that the reason for this improved performance is related to the way light is propagated through the length of an optical fiber. Normally, light enters an optical fiber through an approximately square boundary angle relative to the longitudinal axis of the optical fiber. Depending on the numerical aperture of the optical fiber, only light entering the optical fiber at an angle less than the critical angle will not be transmitted through the length of the optical fiber. Light at angles greater than the numerical aperture will leak out and be lost through the cladding, decreasing the relative efficiency of the optical fiber. In the present claimed invention, it is believed that the proximal terminal structure  26   a,    126   a,    226   a  functions to convert high order mode light (or at least a higher proportion of it) emitted from the light source, to low order mode light, allowing a greater amount of low order mode light energy to travel the length of the fiber optic illumination device  10 . Upon the transmitted light reaching the distal terminal structure  26   b,    126   b,    226   b  it is believed that the light (or at least a higher proportion of it) is converted from high order mode light to low order mode light, resulting in a greater illumination of the target area (less light on the outer areas of the numerical aperture area) to deliver light in the target viewing area. 
       Method of Manufacturing 
       [0114]      FIG. 6  is a flow chart illustrating the steps involved in manufacturing the fiber optic illumination device  10  of the present invention. Preparing the proximal section  10   a  of the fiber optic illumination device  10  involves initially procuring  50  a length of optical fiber  16  having a proximal end  16   a,  a distal end  16   b,  an appropriate length and diameter, a cladding  20  layer and a core  24  layer. The proximal  16   a  and distal  16   b  ends of the optical fiber  16  may be trimmed  52  at this point to ensure uniformity and precision of cut. Next, a length of hypotube is slid  54  over the proximal end  16   a  of the optical fiber  16  allowing a portion (not shown) of the optical fiber  16  to extend from the proximal end  22   a  of the crimp sleeve  22  sufficient to extend through the channel  12   c  and from the proximal end  12   a  of the connector  12 . The crimp sleeve  22  is exposed to a sufficient amount of external, mechanical force  56  to cause the crimp sleeve  22  to take a permanent set without damaging the optical fiber  16 , thus securing the crimp sleeve  22  to the optical fiber  16 . 
         [0115]    In a separate operation a proximal strain relief member  14  is attached to the provided  58  connector  12  by inserting  60  the proximal strain relief member  14  into the channel  12   c  through the distal end  12   b.  As discussed above, the outer diameter (unnumbered) of the proximal strain relief member  14  in one embodiment is slightly larger than the outer diameter (unnumbered) of the channel  12   c,  resulting in an interference fit. The optical fiber  16 , with attached crimp sleeve  22  is fitted  62  through the connector  12  and trimmed to extend a length of optical fiber  16  from the proximal end  12   a  of the connector  12 . The exposed proximal end  16   a  of the optical fiber  16  is then exposed  64  to a sufficient amount of heat and air to cause the exposed proximal end  16   a  of the optical fiber  16  to reflow, resulting in the simultaneous expansion of the core  24  and cladding  20  and the formation of a proximal terminal structure  26   a  integral with the core  24  extending proximally from the connector  12 . Due to the wide range and great variability of optical fibers available it is impossible to precisely state a sufficient amount of heat and air to cause the optical fiber to reflow. A temperature range of approximately 400-500 degrees F. at a time between approximately 2-5 seconds and airflow between approximately 5-20 standard cubic feet per minute is known to be effective in causing an optical fiber  16  to reflow, resulting in the formation of a proximal terminal structure  26   a,    126   a,    226   a  which is integral with the core  24 . The formation of the proximal terminal structure  26   a  serves to secure the optical fiber  16  to the connector  12  without the use of chemical or mechanical fasteners and also provides a structure similar to a lens, which is integral with at least the core  24  along the length of the fiber optic illumination device  10 . 
         [0116]    In preparing the distal end  10   b  of the fiber optic illumination device  10  a length of hypotube is provided  66 , which will function as the distal tube  18 , which may be shaped to provide a specific shape required by a particular surgical retractor, surgical hardware or physician preference. Following shaping, the distal end  16   b  of the optical fiber  16  is slid  68  through the distal tube  18  until a sufficient length of optical fiber  16  extends distally from the distal end  18   c  of the distal tube  18 . The distal tube  18  is exposed to a sufficient amount of external, mechanical force to cause the distal tube  18  to take a permanent set without damaging the optical fiber  16 , thus crimping  70  the optical fiber  16  to distal tube  18 . The distally extending end (unnumbered) of the optical fiber  16  is then attached to the distal end  18   c  of the distal tube  18  by means of exposing  72  the optical fiber  16  to a sufficient amount of heat and air to cause the optical fiber  16  to reflow, resulting in the simultaneous melting and expansion of the distal end  24   b  of the core  24  and cladding  20  and the formation of a distal terminal structure  26   b  integral with core  24  extending distally from the distal tube  18 . Due to the wide range and great variability of optical fibers available it is impossible to precisely state a sufficient amount of heat and air to cause the optical fiber to reflow. A temperature range of approximately 400-500 degrees F. at a time between approximately 2-5 seconds and airflow between approximately 5-20 standard cubic feet per minute is known to be effective in causing an optical fiber  16  to reflow, resulting in the formation of a distal terminal structure  26   b,    126   b,    226   b  which is integral with the core  24 . The formation of the distal terminal structure  26   b,    126   b,    226   b  serves to secure the optical fiber  16  from pulling through the distal tube  18  without the use of chemical or mechanical fasteners and also provides a structure similar to a lens, but which is integral with the optical fiber  16  along the length of the fiber optic illumination device  10  between the proximal terminal structure  26   a  to the distal terminal structure  26   b,  allowing uninterrupted light communication between the proximal terminal structure  26   a  and distal terminal structure  26   b.  This completes manufacture of the fiber optic illumination device  10 . Sterilization and packaging area done following manufacture of the illumination device  10 . 
       Use 
       [0117]    Using the fiber optic illumination device  10  of the present invention involves initially preparing the patient and exposing the surgical site, following by insertion of a surgical retractor to safely maximize the area available to the surgeon during the procedure. This is followed by removing the fiber optic illumination device  10  from sterile packaging and attaching the fiber optic illumination device  10  via the proximal end  12   a  of the connector  12  to a light source (not shown) which could be halogen, LED or other light sources. The distal end  24   b  of the fiber optic illumination device  10  can then be positioned as desired by the physician and may be attached via the distal tube  18  to the retractor itself or other operating room apparatus. The light source is energized causing light to flow through the fiber optic illumination device  10 , illuminating the surgical site. Following completion of the procedure, the fiber optic illumination device  10  may be disposed of.