Abstract:
An endoscope that has an integrated light source and camera mounted at the distal end of the endoscope. The light source is a class of LED devices constructed of high-efficiency LEDs that emit narrow-band blue light coupled with phosphors, which cause a nearly natural “white” light to be emitted. The LEDs are coupled to a waveguide for transmission of the light to the distal end of the endoscope.

Description:
RELATED PATENT APPLICATIONS 
   The present application is a continuation of U.S. patent application, Ser. No. 10/393,580, filed on Mar. 21, 2003, now abandoned, which claims priority to U.S. Provisional Application Ser. No. 60/366,727 filed Mar. 22, 2002, the entire disclosure of which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates in general to a video scope, and more particularly, to a endoscope useful for medical procedures that has a self-contained camera and light source. 
   BACKGROUND OF THE INVENTION 
   Endoscopes are used with increasing frequency in operating rooms. They have facilitated the growth of new minimally invasive procedures that allow surgery to be done through small openings into internal body cavities created by trocars and into external body cavities through the mouth and anus. The vision necessary to do minimally invasive surgery is accomplished by inserting endoscopes equipped with video cameras (video endoscopes) that display full motion images on a video monitor. These monitors are placed near the operative field where the surgeon can see them. 
   Although video endoscopes and the associated equipment help facilitate these minimally invasive procedures there are several factors about these systems that are currently undesirable. The most important are; i) the bulk of the equipment that is necessary to create and display the images and their proximity to the operative site and ii) the location and number of interconnecting elements. Traditional endoscopes require the use of a collection of electronic components commonly referred to as a video tower. This rack of equipment includes several electronic components that provide functions such as: processing of video signals from the camera, supplying power to the tower-based equipment and the camera, supplying visible light energy to the endoscope and displaying the video images to the surgeon. The video endoscope itself is connected to this video tower through a camera wire and an optical fiber bundle that serves as a light transmission source. This optical fiber bundle is necessary to carry light from the tower-based source to the endoscope. Due to the light losses inherent to the optical fiber bundle, they are typically no longer than six feet. The lengths of these interconnecting cables require that the video tower be forced to be in the footprint of the operative site. Using current technology, the video tower takes up significant space near the patient and the operating room staff. In addition, the optical fiber bundles heavy enough to which make the endoscope hard to manage. 
   As minimally invasive instruments become more advanced there is a drive to create instruments that go through smaller ports, and thus leave smaller wounds in the patient. Video Endoscopes must keep pace with this decrease in cross section. 
   Because of these drawbacks in the traditional video endoscope systems, there have been new designs that have tried to remove as many of the external equipment in the system as are possible. This would take equipment out of the footprint of the operative area. One example includes scope designs that remove the external light source from the video endoscope systems. In, for example, U.S. Pat. No. 5,908,294 by Schick et al. and U.S. Pat. No. 6,190,309 by Ooshima et al white light sources, specifically white light emitting diodes (LEDs), are placed at the distal end of the video endoscope to provide illumination to the operative site. This arrangement eliminates the need to have an external light source or a fiber optic cable. Because the light sources in this embodiment are placed distal to the camera itself and must still be within the cross section of the instrument, Video endoscopes so configured do not have the ability to view axially, as would be needed in endoscopic procedures. In this embodiment, only video endoscopes that view in directions away from the axis of the shaft of the instrument are possible. See, for example, U.S. Pat. No. 5,908,294 by Schick et al. and U.S. Pat. No. 6,190,309 by Ooshima et al. 
   An improved video endoscope system would be one that removes the need for external equipment such as light sources and the associated connection cables, while still allowing the video endoscope to view axially relative to the shaft of the instrument. A further advantage of an improved video endoscope system would be one that had an entirely wireless design enabled by operation from battery power supplies and video data communications via modulated electromagnetic energy or modulated visible or invisible light. Such a system would have no need for support equipment within the footprint of the operative area except for the compatible video data receiver and a display monitor. 
   SUMMARY OF THE INVENTION 
   The present invention advantageously avoids the aforementioned drawbacks of the prior art by providing a novel light source arrangement in combination with a light guide and camera located, in one embodiment, at the distal end of the endoscope that results in a conveniently packaged video scope for use in medical surgical procedures. 
   In one aspect of the invention, the light source is a class of LED devices constructed of high-efficiency LEDs that emit narrow-band blue light coupled with phosphors, which cause a nearly natural “white” light to be emitted. The LEDs are coupled to a waveguide for transmission of the light to the distal end of the endoscope. 
   In an alternate embodiment of the invention, a camera/light unit attaches to the proximal end of the endoscope and provides for an LED light source to be communicated to the endoscope. 
   The present invention has, without limitation, application in conventional endoscopic and open surgical instrumentation as well as application in robotic-assisted surgery. 
   These and other features and advantages of the present invention will become apparent from the following more detailed description, when taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to organization and methods of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in conjunction with the accompanying drawings in which: 
       FIG. 1  is an isometric view of an video endoscopic system configured as a rigid laparoscope; 
       FIG. 2  shows a side view of the present invention endoscope; 
       FIG. 3  shows a cut-away view of the end-effector and the distal end of the tubular portion of the present invention; 
       FIG. 4  shows a cross section view of one embodiment of the light guide; 
       FIGS. 5A-B  show two alternate embodiments of the lighting system that is integrated inside the tubular portion of the video endoscope; 
       FIG. 5C  is an alternate embodiment of the light guide and light source integrated within the end-effector and tubular portion of the present invention; 
       FIG. 6  shows a cut-away view of the body and the proximal end of the tubular portion of the present invention endoscope; 
       FIG. 7  shows a second embodiment of the present invention video endoscope; 
       FIG. 8  shows a cross sectional view of the camera/light unit of the embodiment shown in  FIG. 7 ; 
       FIG. 9  shows an isometric view of an alternate embodiment of the present invention video endoscope; 
       FIG. 10  shows a cross sectional view of the camera unit of  FIG. 9 ; and 
       FIGS. 11 and 12  show cross sectional views of alternate embodiments of the light unit shown in  FIG. 9 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Before explaining the present invention in detail, it should be noted that the invention is not limited in its application or use to the details of construction and arrangement of parts illustrated in the accompanying drawings and description. The illustrative embodiments of the invention may be implemented or incorporated in other embodiments, variations and modifications, and may be practiced or carried out in various ways. Furthermore, unless otherwise indicated, the terms and expressions employed herein have been chosen for the purpose of describing the illustrative embodiments of the present invention for the convenience of the reader and are not for the purpose of limiting the invention. Further, it is understood that any one or more of the following-described embodiments, expressions of embodiments, examples, methods, etc. can be combined with any one or more of the other following-described embodiments, expressions of embodiments, examples, methods, etc. 
     FIG. 1  shows an isometric view of a video endoscopic system  10  configured as a rigid laparoscope. This system  10  includes an endoscope  20 , a monitor  22  and a connector cable  24  between the two. The endoscope  20  has both lighting and imaging capabilities incorporated into it. The system will illuminate the operative field and generate a video image stream that can be transferred from the video endoscope  20  by the connector cable  24  and viewed on the monitor  22  by the user. 
     FIG. 2  shows a side view of the endoscope  20 . The endoscope  20  comprises an end-effector  26 , a tubular portion  28  and a body  30 . The connector cable  24  is connected to the body  30  of the endoscope  20 . For a rigid laparoscope, the end-effector  26  and tubular portion  28  is designed so that it will fit through a standard entry port, such as a trocar, for laparoscopic surgery. 
   Referring now to  FIG. 3  the end-effector  26  comprises a light guide  40 , a camera  42  and a camera connector  44 . The camera  42  is positioned concentric to the light guide  40  and is connected to the body  30  by the camera connector  44 . Non-symmetric configurations are also possible. The camera connector  44  supplies power to the camera  42  and transfers the image generated by the camera  42  proximally to the body  30 . A light source  50  is integrated within the tubular portion  28 , but could be integrated anywhere within the video endoscope  20 . The light source  50  is a white light source that is compatible to the camera  42  for optimal picture quality. In the preferred embodiment the white light source is white light LEDs that are constructed from blue light LED elements packaged with a phosphorus coating. When these blue LEDs emit their blue light onto the phosphorus coating, the coating emits light in the full white light spectrum. An alternative light source is tungsten style gas filled bulbs. 
   The light source  50  is mounted on a light source mounting board  52  that is optimally positioned within the tubular portion and puts it at an optimal position to couple light into the light guide  40 . The light guide  40  is designed to concentrate the light generated by the light source  50  and allow it to pass around the camera and out of the distal end of the video endoscope  20 . The light source power cable  54  supplies power from the power source (not shown) to the light source  50  and is connected to it by the light source mounting board  52 . 
     FIG. 4  shows a cross section of the light guide  40 . In a preferred embodiment the light guide  40  is constructed in one piece of a molded plastic such as polycarbonate. In alternative embodiments however, the light guide could be constructed of a variety of translucent materials such as glass or it could be made in a plurality of radial segments that ran along the axis of the device such as optical fibers. The light guide  40  comprises a concentrating portion  60  and a transmission portion  62 . The concentrating portion  60  is further comprised of a reflecting angle ?. The reflecting angle ? is designed to be under the critical angle of the material that the light guide  40 . Snell&#39;s Law dictates that any light that strikes an interface between two materials shall be totally internally reflected if it strikes the interface at an angle greater than the critical angle. This critical angle is calculated based on the difference in indexes of refraction between the two materials. For a typical plastic/air interface the critical angle is approximately 46-49 degrees. For the preferred embodiment with a single molded polycarbonate light guide a preferred angle would be approximately 50-60 degrees for optimal performance. It is known in the art that applying a cladding to the surface of the light guide could greatly improve the efficiency of the transmission of light by creating a plastic/cladding interface that has a significantly smaller critical angle than with the plastic/air interface. Optical fibers use this theory by adding doping chemicals to the plastic to create the cladding layer. This total internal reflection will cause the light to be gradually concentrated and passed onto the transmission portion  62  with minimal losses. The transmission portion  62  is designed so as to be of limited cross sectional area to minimize its profile without generating losses in the light that is transmitted through it. An alternative light guide could be as described above (with or without cladding) with the addition of chemical elements in a controlled manner to the external surfaces that create a gradient in the index of refraction to reduce optical loss through the plastic/air interface at all points. 
     FIGS. 5A-B  show two alternate embodiments of the lighting system that is integrated inside the tubular portion  28 . In  FIG. 5A  the light source  64  is a single package that contains multiple light source elements. In  FIG. 5B  the light source  66  is a plurality of packages that each contain a single light source element. The light source in  FIG. 5B  could be standard LED packages, such as a T1 LED package, that are grouped together at maximum density.  FIG. 5A  shows an improved LED packaging scheme whereby multiple blue LED elements and connected in a circuit and packaged within one housing that has phosphorus coating on it. This embodiment allows for a higher density of LED elements in the same space than can be achieved through utilization of the off the shelf designs. This would greatly enhance the illumination power of the light source  50  and allows the video endoscope  20  to view images at a greater distance or with increased image quality. In  FIG. 5C , the phosphorus coating  51  is removed from the light source  50  and is placed at the distal portion of the transmission portion  62  with an additional plastic interface  63  at the most distal point to isolate the phosphorous coating from the external environment. 
     FIG. 6  shows a cross section view of the body  30  and the proximal end of the tubular portion  28 . The proximal end of the tubular portion  28  is connected to the distal portion of the body  30 . The body further comprises a power source  70  and a control switch  72  located on the outside of the body and is accessible by the user. The power source  70  can be any version of a wireless power supply that is known in the art, such as a battery. The camera connector  44  and light source connector cable  54  passes from the camera  42  and light source  50 , respectively, at the distal end, through the tubular portion  28  and into the body  30 . As the camera connector  44  passes into the body  30  it divides into two different leads, the camera source power cable  44   b  and the video signal and control cable  44   a . The camera and light source power cable  44   b  and  54  attach to the control switch  72  and the signal cable  44   a  passes through the body and exits on the proximal end. As it exits the proximal end of the body it becomes the connector cable. The user manipulates the control switch  72  so that the power delivered to the light source is varied, thereby controlling illumination level. When the light source  50  is off, power is removed from the camera  42  in the end effector. The signal cable  44   a  carries the image signal from the camera  42  to the monitor  22  via connector cable  24 . 
     FIG. 7  shows a second embodiment of a video endoscope system  120 . The endoscope system  120  comprises an endoscope  121  light cable  130  and a camera/light unit  140 . The camera/light unit  140  attaches to the proximal end of the endoscope  121 . The light cable  130  attaches to the camera/light unit  140  at its proximal end, while its distal end attaches to the light source port of the endoscope  121 . The camera/light unit  140  contains the imaging system, light system and signal transmission means for the endoscope  121 . In the preferred embodiment, the signal transmission means could be a RF transmitter such as the 1.4 GHz transmitters used with wireless security cameras. The transmission means could alternatively be one of several methods of transmission protocols that are known to those skilled in the art, such as the Bluetooth system. 
   Referring now to  FIG. 8 , the camera/light unit  140  comprises an endoscope adapter  142 , camera,  144  signal transmission means  146 , power source  148 , control switch  150 , white light source  152  and focusing lens  154 . These are all contained within the body of the camera/light unit  140 . The endoscope adapter  142  is designed in such a way as to be operatively connected to the endoscope  121  to couple its optics into the camera. The camera  144  receives the image from the optics of the endoscope  121  and convert it into a video signal. The signal transmission means  146  is operatively connected to the camera  144  in order to take its video signal and transmit it to a remote receiver. Though this is shown in  FIG. 8  as a wireless connection, it is obvious that it could be a hard-wired connection. The power source  148  supplies power to the white light source  152  and the camera unit  144  through its connection that passes through the control switch  150 . The focusing lens  154  gathers the light generated by the white light source  152  and concentrates it to a smaller cross sectional area so that it can be efficiently coupled into the light cable  130  that connects to the camera/light unit at this port. An alternative embodiment would be constructed form a plurality of blue LED die covered by a phosphorus coating and a plurality of focusing lens elements approximated to the light cable attachment. 
     FIG. 9  shows an isometric view of a third embodiment of a video endoscope system  220 , which comprises an endoscope  221 , a camera unit  222 , a light unit  224  and a power cord  226 . The power cord  226  connects the camera unit  222  to the light unit  224  and passes power to the light unit  224 . The camera unit  222  connects to the endoscope  221  at its proximal end and couples into the optics there, while the light unit  224  couples into the light port of the endoscope  221 . 
     FIG. 10  shows a cross sectional view of the camera unit  222 . The camera unit further comprises a power source  230 , an imaging chip  232 , a transmission circuit  234 , a signal transmission means  238  and a body  236 . The imaging chip  232  is placed so that the image carried through the optics of the endoscope  221  is focused onto the imaging chip  232 . The imaging chip  232  comprises three major components; the image array, the timing and control circuits and the video processing circuits. The image array is composed of individual pixels that convert the intensity of light shown on it into electrical signals and in some models converts this electrical signal into a digital signal. The video processing circuit reads these signals and formats it into a signal that is readable by the display, such as an NTSC or PAL signal. It is known to those skilled in the art that each of these three functions can be separated into different locations and chips. The image array can be constructed from either a CMOS or a CCD technology. If the image array is based on the CMOS technology then all three processes can be included into a single chip design. An example of a single chip design would be the Omnivision OV7910. This chip has two wires for power input and two for an NTSC signal output. The power supply  230  is connected to the imaging chip  232 , the transmission circuit  234  and the power cord. The imaging chip  232  is connected to the transmission circuit  234  so that the signal created by the imaging chip  232  is passed to it. The transmission circuit  234  is operatively connected to the signal transmission means  238  so that the signal is transmitted to a remote display system  22 . Although the signal transmission means in  FIG. 10  is shown as a wireless connection, it is obvious that this connection could also be a hard-wired one. 
     FIGS. 11 and 12  show cross sectional views of alternate embodiments of the light unit  224 . Each embodiment comprises a light unit body  240   a, b , a white light source  244   a, b , a collimator  246   a, b , and a circuit board  248   a, b . The top of the light unit body is designed in such a way as to be operatively connected to the light port of the endoscope  221 . Inside the light unit body, the white light source  244   a, b  is connected to the circuit board  248   a, b . The circuit boards are connected to the power cord  250  and delivers power from the power supply to the white light source  244   a, b . In  FIG. 11  the white light source  244   a  is arranged in a planar fashion and the collimator  246   a  is designed to concentrate and collimate the light generated by the white light source into the light port of the endoscope  221 . In  FIG. 12  the white light source  244   b  is arranged in an arc so that its light is focused on a collimator lens system  246   b . In this embodiment the collimator is a lens that will concentrate and collimate the light into the light port of the endoscope  221 . 
   The foregoing description of several expressions of embodiments and methods of the invention has been presented for purposes of illustration. It is not intended to be exhaustive or to limit the invention to the precise forms and procedures disclosed, and obviously many modifications and variations are possible in light of the above teaching. For example, as would be apparent to those skilled in the art, the disclosures herein of the ultrasonic systems and methods have equal application in robotic assisted surgery taking into account the obvious modifications of the invention to be compatible with such a robotic system. It is intended that the scope of the invention be defined by the claims appended hereto.