Patent Document

REFERENCE TO RELATED CASES 
     This application is a divisional of and claims priority to U.S. patent application Ser. No. 12/644,654, filed on Dec. 22, 2009, which claims priority from U.S. Provisional Application 61/139,902, filed on Dec. 22, 2008 and titled “Slip-Clip Fiber Bender for Enhanced Coagulation.” 
    
    
     BACKGROUND 
     Optic fibers guide laser light from a first end of the optic fiber to a second end of the optic fiber. The light is maintained within the optic fiber due to total internal reflection that occurs at a boundary between a central core of the optic fiber and a surrounding cladding. This total internal reflection is caused by a difference in the index of refraction of the core relative to the cladding. 
     In some optic fibers, the laser light is emitted from the end of the optic fiber. In other optic fibers, the end of the optic fiber is altered so that light guided within the optic fiber is emitted from a side surface of the optic fiber. Typically, this alteration involves removing the cladding around the core at the end of the optic fiber and forming a total internal reflection surface on the end of the core. The total internal reflection surface is at an oblique angle to the axis of the optic fiber such that light from the optic fiber is reflected off the surface and out the side of the core. Such optic fibers are known as side-firing optic fibers. 
     The beam of laser light emitted by optic fibers of the prior art has a fixed diameter at a given distance from the optic fiber tip. This diameter is determined by the geometry and optics of the optic fiber. 
     The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. 
     SUMMARY 
     A method positions a first end of an optic fiber a distance from a target applies a laser light to a second end of the optic fiber such that the laser light is guided by the optic fiber from the second end to the first end of the optic fiber and is emitted from the first end of the optic fiber toward the target as a beam of light. The beam of light has a first area of incidence at the target. The optic fiber is then bent such that the beam of light continues to reach the target and such that the area of incidence of the beam of light at the target changes without changing the distance between the first end of the optic fiber and the target. 
     A device comprises a first plate having at least two raised portions and a second plate having at least two raised portions. A spring means is biased to pull the plates apart. A metal case encloses the first plate and the second plate and defines a first opening on a first end of the metal case and a second opening on a second end of the metal case wherein the first opening and the second opening are sized to accept an optic fiber. 
     A method comprises placing a portion of an optic fiber in an optic fiber bending device and closing a case of the optic fiber bending device such that the case completely shields from view the portion of the optic fiber that is within the optic fiber bending device. Pressure is applied to a first plate and a second plate in the fiber bending device to cause the first plate and the second plate to move toward each other and thereby bend the optic fiber. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of a laser system. 
         FIG. 2  is a flow diagram of a method of altering an area of incidence of laser light. 
         FIG. 3  is a top view of a target with an incident light beam without optic fiber bending. 
         FIG. 4  is a top view of the target of  FIG. 3  with an incident light beam with optic fiber bending. 
         FIG. 5  is a cross-sectional side view of an optic fiber bending device under one embodiment. 
         FIG. 6  is a cross-sectional side view of the optic fiber bending device of  FIG. 5  showing an optic fiber being bent. 
         FIG. 7  is a top view of the optic fiber bending device of  FIG. 5 . 
         FIG. 8  is a back view of the optic fiber bending device of  FIG. 5 . 
         FIG. 9  is a top view of the optic fiber bending device of  FIG. 5  with the case open. 
         FIG. 10  is a cross-sectional side view of an optic fiber bending device under a second embodiment. 
         FIG. 11  is a cross-sectional side view of the optic fiber bending device of  FIG. 10  showing an optic fiber being bent. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a schematic illustration of a laser system  100  in accordance with some embodiments. The laser system  100  includes a laser production systems  101 , an optic fiber  168 , and a side-firing delivery tip  170 . Laser production system  101  includes a gain medium  102 , a pump module  104  and a laser resonator  106 . In one embodiment, the gain medium  102  is a doped crystalline host that is configured to absorb pump energy  108  generated by the pump module  104  having a wavelength that is within an operating wavelength (i.e., absorption spectra) range of the gain medium  102 . In one embodiment, the gain medium  102  is end-pumped by the pump energy  108 , which is transmitted through a folding mirror  110  that is transmissive at the wavelength of the pump energy  108 . The gain medium  102  absorbs the pump energy  108  and responsively outputs laser light  112 . 
     In some embodiments, the gain medium  102  is water cooled (not shown) along the sides of the host (not shown). In one embodiment, the gain medium  102  includes an undoped end cap  114  bonded on a first end  116  of the gain medium  102 , and an undoped end cap  118  bonded on a second end  120  of the gain medium  102 . In one embodiment, the end  120  is coated so that it is reflective at the pump energy wavelength, while transmissive at a resonant mode of the system  100 . In this manner, the pump energy that is unabsorbed at the second end  120  is redirected back through the gain medium  102  to be absorbed. 
     The laser resonator  106  is configured to generate a harmonic of the laser light  112  output from the gain medium  102 . In one embodiment, the laser resonator  106  includes a non-linear crystal (NLC)  150 , such as a lithium borate (LBO) crystal or a potassium titanyl phosphate crystal (KTP), for generating a second harmonic of the laser beam  112  emitted by the gain medium  102 . 
     In one embodiment, the gain medium  102  comprises a yttrium-aluminum-garnet crystal (YAG) rod with neodymium atoms dispersed in the YAG rod to form a Nd:YAG gain medium  102 . The Nd:YAG gain medium  102  converts the pump light into the laser light  112  having a primary wavelength of 1064 nm. The laser resonator  106  generates the second harmonic of the 1064 nm laser light  164  having a wavelength of 532 nm. One advantage of the 532 nm wavelength is that it is strongly absorbed by hemoglobin in blood and, therefore, is useful in medical procedures to cut, vaporize and coagulate vascular tissue. 
     In one embodiment, the laser resonator  106  includes a Q-switch  152  that operates to change the laser beam  112  into a train of short pulses with high peak power to increase the conversion efficiency of the second harmonic laser beam. 
     The laser resonator  106  also includes reflecting mirrors  156 ,  158  and  162 , folding mirror  110 , and output coupler  160 . The mirrors  110 ,  156 ,  158  and  162 , and output coupler  160  are highly reflective at the primary wavelength (e.g., 1064 nm). The output coupler  160  is highly transmissive at the second harmonic output wavelength (e.g., 532 nm). The primary wavelength laser beam (e.g., 1064 nm) inside the resonator  106  bounces back and forth along the path between the mirrors  158  and  162 , passing through the gain medium  102  and the non-linear crystal  150  to be frequency doubled to the second harmonic output wavelength (e.g., 532 nm) beam, which is discharged through output coupler  160  as the output laser  164 . The Z-shaped resonant cavity can be configured as discussed in U.S. Pat. No. 5,025,446 by Kuizenga. 
     An optical coupler  166  receives output laser  164  and introduces laser  164  into optical fiber  168 . The optic fiber  168  generally comprises multiple concentric layers that include an outer nylon jacket, a buffer or hard cladding, a cladding and a core. The cladding is bonded to the core and the cladding and core operate as a waveguide that allows electromagnetic energy, such as laser beam  164 , to travel through the core. 
     Laser beam  164  is guided along optic fiber  168  through optic fiber bending device  169  to side-firing delivery tip  170 , which emits the laser beam at an angle to the axis of optic fiber  168 . Optic fiber bending device  169  is a hand-held device that can be changed from a state in which optic fiber  168  is not bent to a state in which optic fiber  168  is bent and back again using only a single hand. For embodiments used in medical procedures, this allows medical personnel to bend the optic fiber using one hand while positioning the optic fiber relative to a target using the other hand. When optic fiber  168  is bent by bending device  169 , laser beam  164  spreads out such that the area of incidence of the laser beam on a target is larger when optic fiber  168  is bent by bending device  169  than when optic fiber  168  is not bent by bending device  169 . 
       FIG. 2  is a flow diagram of a method for altering the area of incidence of a laser beam on a target. In step  200  of  FIG. 2 , an optic fiber is placed within a bending device. In step  202 , a first end of the optic fiber is positioned near a target. At step  204 , a laser light is applied to a second end of the optic fiber causing the laser light to be guided by the optic fiber to the first end of the optic fiber where it is emitted toward the target. The emitted laser light strikes the target across an area of incidence on the target. At step  206 , the bending device is manipulated with one hand to bring plates within the bending device closer together and thereby bend the optic fiber. This alters the emitted laser beam such that the area of incidence of the laser beam on the target increases without changing the distance between the tip of the optic fiber and the target. 
       FIG. 3  shows a target  300  with an area of incidence  302  of a laser beam that is formed while an optic fiber is not bent by a bending device of the present invention. In  FIG. 3 , the area of incidence is shown to be a circle with a radius  304 , however other shapes are possible given the optics of the optic fiber tip, the contours of the target, and scattering effects.  FIG. 4  shows a target  400  with an area of incidence  402  of a laser beam that is formed when an optic fiber is bent by a bending device of the present embodiment. In  FIG. 4 , the area of incidence is shown to be a circle with a radius  404 , however other shapes are possible given the optics of the optic fiber tip, the contours of the target, and scattering effects. Radius  404  is larger than radius  304  and as such, area of incidence  402  is larger than area of incidence  302 . Note that the differences in areas of incidence  402  and  302  are only due to the bending of the optic fiber. The same target, the same distance from target to optic fiber tip, and the same optic fiber and optic fiber tip are used in both  FIGS. 3 and 4 . The only difference between  FIGS. 3 and 4  is that in  FIG. 3 , the optic fiber is not bent and in  FIG. 4  the optic fiber is bent. 
       FIG. 5  provides a cross-sectional side view of an optic fiber bending device  500  under one embodiment. Optic fiber bending device  500  includes an outer case  504 , which under one embodiment as an outer plastic shell  506  and an inner metal layer  508 . An optic fiber  502  extends through openings  505  and  507  in case  504 , which are sized to fit optic fiber  502 , and rests upon three raised portions  510 ,  512 , and  514  of a fixed plate  516 . Raised portions  510 ,  512 , and  514  under one embodiment are hollow half-cylinders having a radius of curvature of 0.25 inches with the tops of each cylinder separated horizontally by a distance  518  of 1 inch. Under one embodiment, raised portions  512 ,  514 , and  516  are vertically aligned to ensure uniform contact with optic fiber  502 . Fixed plate  516  is mounted on metal layer  508  of a bottom portion  511  of case  504 . A moveable plate  520  having raised portions  522  and  524  extends from a top portion  513  of case  504  and is positioned opposite fixed plate  516  such that raised portions  522  and  524  are aligned with the spaces between raised portions  510 ,  512 , and  514  of fixed plate  516 . Under one embodiment, raised portions  522  and  524  are hollow half-cylinders with a radius of curvature of 0.25 inches and the tops of the half-cylinders are separated horizontally by a distance  526 , which under one embodiment is 1 inch. Under one embodiment, raised portions  522  and  524  are vertically aligned. The top of raised portion  522  is separated from the top of raised portion  510  by a horizontal distance  528 , which under one embodiment is 0.5 inches. 
     Moveable plate  520  can move in a vertical direction  530  toward and away from fixed plate  516 . Moveable plate  520  is driven away from fixed plate  516  by a spring  532  mounted on a post  534  that is connected to moveable plate  520  and that passes through case  504 . Spring  532  engages the top of case  504  and the bottom of the post cap  536  that is attached to the top of post  534 . A flexible cover  540  covers post cap  536 . By squeezing a contact point  542  on the top of cover  540  relative to a bottom  544  of case  504 , a user is able to move plate  520  toward fixed plate  516 . 
     The results of such movement are shown in  FIG. 6  where optic fiber bending device  500  is shown in a state in which optic fiber  502  has been bent by the movement of movable plate  520  toward fixed plate  516 . In particular, optic fiber  502  includes multiple bends created by movement of raised portion  522  between raised portions  510  and  512  and the movement of raised portion  524  between raised portions  512  and  514 . By comparing  FIGS. 5 and 6 , it can be seen that spring  532  is compressed in  FIG. 6  relative to  FIG. 5  and therefore provides a force that tends to lift movable plate  520  away from fixed plate  516 . 
     The vertical movement of moveable plate  520  is controlled in part by guides  600  and  602 . In addition, the vertical movement of post cap  536  is assisted by guides  604  and  606 . Under one embodiment, a locking mechanism is formed form portions of cap  536  and one of guides  604  and  606  that allows optic fiber bending device  500  to be locked into the bending state shown in  FIG. 6 . A release button, not shown, can be provided in the locking mechanism so that optic fiber bending device  500  may be released from the bending state shown in  FIG. 6 . 
     Movement of moveable plate  520  is restrained by restraining or stopping elements  610  and  612 , which prevent moveable plate  520  from moving closer to fixed plate  516  than a set distance. Under one embodiment, restraining elements  610  and  612  are screws that screw into fixed plate  516  and extend out of the top of fixed plate  516  so as to engage moveable plate  520  as it moves down toward fixed plate  516 . Using such screws, it is possible to adjust the minimum distance between moveable plate  520  and fixed plate  516 , and thereby adjust the maximum amount of bending that can be applied to optic fiber  502 . If the optic fiber is bent too much, the optic fiber will break, allowing laser light to escape the optic fiber. As such, the restraining elements assist in preventing the optic fiber from breaking during bending. 
     Optic fiber bending device  500  includes a printed circuit board  620  having a light sensor  622 , a speaker controller  624 , and light emitting diode controller  626 . In addition, printed circuit board  620  contains a speaker  628  that extends through case  504  and a light emitting diode assembly  630  that also extends through case  504 . The circuits on printed circuit board  620  are powered by a battery  632  that in one embodiment is mounted in lower portion  511  of optic fiber bending device  500 . 
     Light emitting diode controller  626  receives a signal from a contact sensor mounted on restraining element  612  that indicates contact between restraining element  612  and top plate  520 . Upon receiving the sensor signal, light emitting diode controller  626  changes the state of light emitting diode assembly  630  by changing the color of light emitted by light emitting diode assembly  630 , causing light emitting diode assembly  632  to produce light, or causing light emitting diode  630  to stop producing light. Although a light emitting diode assembly has been described, other types of lights may be used. 
     Light sensor  622  detects laser light in case  504 . During normal operation, the laser light guided by optic fiber  502  will remain within optic fiber  502  and therefore will not be emitted into case  504 . However, if optic fiber  502  breaks, laser light will be emitted into case  504  and will be detected by light sensor  622 . If such light is detected by light sensor  622 , light sensor  622  will provide a signal to speaker driver  624 , which will cause speaker  628  to emit a sound that alerts the user to the breakage of optic fiber  502  in case  504 . Such an alert is necessary since breakage of the optic fiber can damage the laser system and can harm the operator either by heating the case or by emitting laser light when the case is opened. As an alternative or an addition to the light sensor, a thermal sensor may be provided that can sense the temperature of the case and that can trigger the speaker driver to generate a sound to indicate fiber breakage if the temperature in the case exceeds a threshold indicating breakage of the optic fiber. 
     In other embodiment, back reflection from a broken fiber can be detected inside the resonator of the laser system by a pick-off from the beam splitter and an existing safety shutter can be used to cut off the laser light. In still further embodiments, a conductor connects light sensor  622  to the laser production system such that when the light sensor  622  detects laser light, the laser production system shuts off the laser output. In other embodiments, a metal-coated optic fiber may be used such that when the metal coating breaks, the laser production system shuts off the laser output. 
     Although visible in the cross-sections of  FIGS. 5 and 6 , the portions of optic fiber  502  that are within case  504  cannot be seen outside of case  504  when case  504  is closed. Thus, case  504  shields from view the portion of the optic fiber that is within the optic fiber bending device. This provides a measure of safety in case the optic fiber breaks while being bent because it contains the laser light within case  504 . 
     In most embodiments, fixed plate  516 , moveable plate  520  and raised portions  510 ,  512 ,  514 ,  522  and  524  are constructed of metal. To avoid breakage of the optic fiber, the raised portions on the metal plates should have a smooth finish and should not dig into the coating or sheath of the optic fiber. In addition, sharp edges should not be present within the optic fiber bending device. 
     Under preferred embodiments, optic fiber bending device  500  has a length  640  that is less than 6 inches. It should also have a height and width that allow it to be held comfortably in one hand. Under one embodiment, the height and width allow optic fiber bending device to be placed with an circle having a radius of 1.5 inches. In some embodiments, case  504  has depressed regions to enable proper support of the fingers and the palm of the user even when gloves are worn by the user. 
       FIG. 7  shows a top view of fiber optic bending device  500  showing light emitting diode assembly  630 , speaker  628 , and flexible covering  540 . 
       FIG. 8  provides a back view of fiber optic bending device  500  showing optic fiber bending device  500  in a partially open state.  FIG. 9  shows a top view of optic fiber bending device  500  in a fully open state. 
     In  FIGS. 8 and 9 , top case portion  513  is shown to be connected to bottom case portion  511  by three hinge assemblies  900 ,  902  and  904 . Top case portion  513  may be pivoted about hinges  900 ,  902 , and  904  relative to bottom case portion  511  to thereby open optic fiber bending device  500 . Further, top case portion  513  includes latch element  810  and bottom case portion  511  includes latch element  812  that cooperate to latch top case portion  513  and bottom case portion  511  together in a closed state and that can be manipulated to unlatch and open case  504 . 
     As shown in  FIG. 9 , lower case portion  511  contains fixed plate  516  with raised portions  510 ,  512 , and  514  as well as restraining or stopping elements  610 ,  612 ,  910 , and  912 . A contact sensor  914  is positioned on top of restraining element  612 . Lower case portion  511  also contains battery  632 . 
     Top case portion  513  contains moveable plate  520  with raised portions  522  and  524  as well as guides  600 ,  602 ,  920 , and  922 , which guide the movement of moveable plate  520 . Upper case portion  800  also contains printed circuit board  620 , which is mounted to upper case portion  513  and contains light emitting diode controller  626 , light sensor  622 , and speaker controller  624 . 
     Upper case portion  513  contains two channels  806  and  906  sized to accept a portion of optic fiber  502 . Lower case portion  511  contains channels  808  and  908  (obscured by optic fiber  502  in  FIG. 9 ) that also accept a portion of optic fiber  502 . 
     To insert optic fiber  502  into optic fiber bending device  500 , the latch mechanism consisting of elements  810  and  812  is manipulated to unlatch optic fiber bending device  500  and top case portion  513  is then rotated relative to bottom case portion  511 . Optic fiber  502  is then placed in channels  808  and  908  before top case portion  513  is closed on bottom case portion  511  such that optic fiber  502  falls within channel portions  806  and  906  of top case portion  513  and such that latch element  810  engages with latch element  812 . Once optic fiber bending device  500  is closed, the ends of optic fiber  502  extending out of optic fiber bending device  500  may be pulled apart to ensure that optic fiber  502  is straight within optic fiber bending device  500 . In alternative embodiments, the optic fiber may be threaded through openings  505  and  507  of case  504  while case  504  is closed. 
     Contact sensor  914  is connected to light emitting diode controller  626  by conductors  930  and  932 , which carry sensor signals from contact sensor  914  to light emitting diode controller  626 . Light sensor  622  is connected to speaker controller  624  by conductors  934  and  936 , which carry sensor signals from light sensor  622  to speaker controller  624 . Power is provided by battery  632  to printed circuit board  620  by conductors  938  and  940 . 
       FIG. 10  provides a cross-sectional side view of an optic fiber bending device  1000  under a second embodiment of the present invention. In  FIG. 10 , an optic fiber  1002  is positioned on raised portions  1010 ,  1012 , and  1014  of a fixed plate  1016 . Raised portions  1010 ,  1012 ,  1014 , and fixed plate  1016  have similar characteristics to raise portions  510 ,  512 ,  514 , and fixed plate  516  of  FIG. 5 . Fixed plate  1016  is attached to the interior of case  1004 , which under one embodiment has an interior metal layer  1008  and an exterior plastic shell  1006 . 
     Optic fiber bending device  1000  has a moveable plate  1020  having raised portions  1022  and  1024  that are similar to moveable plate  520  and raised portions  522  and  524  of optic fiber bending device  500  of  FIG. 5 . Moveable plate  1020  may be moved in a vertical direction  1030  either toward or away from fixed plate  1016 . The vertical movement of moveable plate  1020  is guided by guides  1100  and  1102 . 
     Optic fiber bending device  1000  includes a printed circuit board  1120  having a light sensor  1122 , a speaker controller  1124 , and a light emitting diode controller  1126 . Further, printed circuit board  1120  supports a light emitting diode assembly  1130  that extends out of case  1004  and a speaker  1128  that extends out of case  1004 . A battery  1132  provides power to the electronics on printed circuit board  1120  through conductors (not shown). 
     Moveable plate  1020  is coupled to case  1004  by two spring plates  1034  and  1036 . The spring plates pull moveable plate  1020  away from fixed plate  1016 . 
     A wheel  1040  is mounted to a support structure  1038  by an axle  1042 . Axle  1042  is positioned off-center on wheel  1040  such that when wheel  1040  is rotated it has an eccentric rotation about axle  1042 . Wheel  1040  includes a nub  1044  to provide more friction between the user&#39;s finger or thumb to aid in the rotation of wheel  1040 . 
     In  FIG. 10 , optic fiber bending device  1000  is in a non-bent state such that optic fiber  1002  is straight within optic fiber bending device  1000 . As shown in  FIG. 11 , optic fiber bending device  1000  can be placed in a bent state in which optic fiber  1002  is bent several times by raised portions  1010 ,  1012 ,  1014 ,  1022 , and  1024 . Optic fiber bending device  1000  is placed in the bent state from the non-bent state by rotating wheel  1040  in a direction  1102 . Because of the off-center mounting of wheel  1040 , this rotation forces moveable plate  1020  toward fixed plate  1016  thereby causing raised portions  1022  and  1024  to engage optic fiber  1002  creating bends in optic fiber  1002 . Note that if wheel  1040  is rotated in an opposite direction from direction  1102  after being in the bent state shown in  FIG. 11 , spring plates  1034  and  1036  will cause moveable plate  1020  to retract from fixed plate  1016  allowing optic fiber  1002  to be straight once again. 
     Optic fiber bending devices  500  and  1000  are designed to be manipulated by a user using just one hand. Thus, the user is able to change the state of optic fiber bending devices  500  and  1000  from a bent state to a non-bent state simply using one digit on their hand while holding the optic fiber bending device in that hand. Further, the width and height of optic fiber bending devices  500  and  1000  under one embodiment are sized such that the optic fiber bending device fits within a 1.5 inch diameter circle and such that an average human hand holding the optic fiber device is three-quarters closed while holding the optic fiber bending device. 
     Although two manually operated devices are described above, in other embodiments, the movable plate may be moved using an electromagnetic or piezoelectric motor. 
     Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Technology Category: 3