Abstract:
A video imaging system including an endoscopic device, a camera, a camera control unit and a light source, the camera coupled to the camera control unit and light source via a single cable connection. The cable is advantageously provided as a pair of wires and a light guide where image data and camera information is transmitted over the pair of wires from the camera to the camera control unit, the data and information being multiplexed on the pair of wires; and command signals are sent from the camera control unit to the camera, the command signals based on the received camera information for control of the camera.

Description:
PRIOR APPLICATION 
     This application is a divisional of U.S. patent application No. 10/034,271, filed on Dec. 28, 2001, now U.S. Pat. No. 6,960,161, issued Nov. 1, 2005, and is a divisional of copending U.S. patent application No. 10/249,278, filed Mar. 27, 2003. 
     FIELD OF THE INVENTION 
     This application relates to an endoscopic video imaging system for transmitting communication signals and illuminating light along a single cable between a camera control unit and a camera head. 
     BACKGROUND OF THE INVENTION 
     The field of video endoscopy, to which the present invention generally relates, includes medical diagnostic and therapeutic disciplines that utilize endoscopes to penetrate and view otherwise inaccessible body cavities utilizing minimally invasive surgical procedures. Coupling of video imaging cameras (incorporating solid-state imagers) to endoscopes, for image reproduction, has become standard within the field. Endoscopic video cameras (hereinafter referred to as “camera heads”), are most advantageously small and lightweight for ease of use by medical personnel, and typically incorporate either single or multiple solid-state imagers. Some special purpose endoscopes have integrated (built-in) solid-state imagers, which do not facilitate direct viewing of internal body cavities by medical personnel without an accompanying video imaging system and display. To achieve the desired size and weight, camera head and/or integrated endoscope-camera assembly electronics are typically separated physically from the majority of circuitry required to process and output high-quality, color video images. 
     In known video imaging systems, interconnection between camera control units (“CCUs”) and camera heads is achieved by means of a cable, with usually one cable end permanently fixed to the camera head, while the other cable end is detachably connected to the CCU using a connector. Similar to the camera head itself, it is advantageous that cables be small in diameter and lightweight, but rugged enough to withstand repeated sterilization, accidental gurney wheel “run-over,” and the like. 
     Most cables for endoscopic video cameras include a fiber optic light guide for illumination, the fiber optic light guide being separately distinct from the cable transmitting electronic video signals. Because the operating room has limited space, extra medical equipment typically creates a substantial inconvenience for medical personnel. 
     Existing interconnections between camera heads and CCUs typically comprise dedicated parallel wires to provide greater data carrying capacity. It is meant by “dedicated parallel wires” that each specific signal is transmitted by means of an individual wire, either single for power and control signals or shielded coax for image data, between a camera head and CCU. However, a disadvantage of providing dedicated parallel wires is that typically twenty to thirty separate lines are required to control, energize and receive image data from camera heads, with most signal lines requiring a dedicated connector pin. The more channels required, the greater the diameter, size and corresponding weight of the cable bundle. The larger this bundle becomes, the more likely it is to interfere with medical personnel&#39;s use of the video imaging system. Moreover, utilizing dedicated parallel wire type cabling is undesired when additional functionality is required and added to either the camera head or CCU. To accommodate this new functionality, additional wiring must be incorporated in the cable bundle, requiring equipment redesign and subsequent purchase by customers. Also, as video imaging systems develop, CCUs are becoming programmable for compatibility with various types of camera heads, are adding new control features and are processing different types of video signals. 
     Typically a combined optical electrical connector is provided with optical and electrical components that can move relative to one another within the body of the connector. Disadvantageously, correct and precise adjustments of the respective components are difficult and time consuming, where the poor connection often results in poor system performance. In addition, the separate cables for transmitting illuminating light and information may become tangled thereby becoming an inconvenience for the user. 
     It is therefore desired to provide a video imaging system that utilizes relatively few channels in order to reduce the size and corresponding weight of the cable, while still maintaining high video image quality. 
     It is also desired to provide a video imaging system that incorporates the light source guide for illumination into a single cable with the channel transmitting information between the camera head and camera control unit. 
     It is further desired to provide a video imaging system that has a rugged cable assembly that will not be damaged by day-to-day use in the operating room. 
     It is still further desired to provide a connector where electrical and optical components are in a fixed spatial relationship to one another and are integrated into a single connector so as not to tangle with one another. 
     SUMMARY OF THE INVENTION 
     These and other objects of the invention are achieved in one advantageous embodiment by providing a video imaging system, comprising a camera head for generating image data, a camera control unit, and a cable for connecting the camera head to the camera control unit. The cable includes in a single protective jacket enclosing, at least one channel for transmitting information between the camera head and the camera control unit, and a light source guide for transmitting light to the camera head for use in generating the image data. 
     In another advantageous embodiment a video imaging system is provided comprising a camera head for generating image data, and a cable for transmitting the image data, the cable including in a single protective jacket enclosing, at least one electrical channel for transmitting the image data from the camera head to a camera control unit, and a light source guide for transmitting light to the camera head for use in generating the image data. 
     In a further advantageous embodiment a video imaging system is provided comprising a camera head for generating image data, a camera control unit and a cable, for connecting the camera head to the camera control unit, the cable including, in a single protective jacket enclosing, at least one electrical channel for transmitting information between the camera head and the camera control unit, and a light source guide for transmitting light to the camera head for use in generating the image data. 
     In yet another advantageous embodiment a video imaging system is provided comprising a receptacle having optical and electrical components, for receiving a connector and a connector detachably connectable with the receptacle. The receptacle includes a body with a front surface, a light source guide and an electrical edge-connector terminating beyond the front surface, the light source guide and electrical edge-connector engaging the optical and electrical components, respectively, upon advancement of the connector into the receptacle. 
     A video imaging system is also provided comprising a camera for generating image data, a control unit for controlling the camera and a channel for transmitting a control signal in the nature of camera operating information and the image data from the camera to the control unit. The control signal and the image data are multiplexed on the channel and a light guide transmits light to an object, wherein the camera is receptive of light reflected off of the object thereby generating the image data. 
     The electrical and optical components are in a fixed spatial relationship within the receptacle, so that these components are aligned with electrical and optical connectors of the plug, respectively, when the plug is advanced into the receptacle. 
     The invention and its particular features and advantages will become more apparent from the following detailed description considered with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of the video imaging system illustrating the camera head, the channel connections, the camera control unit, and the illumination light source. 
         FIG. 2  is a depiction of a camera head with a sectional view of the attached cable assembly, the camera control unit and the light source. 
         FIG. 3  is a depiction of the camera control unit, the receptacle, the connector attached to the cable, and the light source. 
         FIG. 4  is a depiction of the connector assembly to be advanced into the receptacle. 
         FIG. 5  is a front section view of the receptacle. 
         FIG. 6  is an assembly drawing of the receptacle. 
         FIG. 7  is a top section view of the camera control unit of  FIG. 1  depicting the light source guide entering the camera control unit from the rear and connecting with the cable through the receptacle. 
         FIG. 8  is a side section view of the camera control unit of  FIG. 1  depicting the light source guide entering the camera control unit from the rear and connecting with the cable through the receptacle. 
         FIG. 9  is a depiction of a section of the camera head of  FIG. 2  showing four channels comprising eight electrical conductors. 
         FIG. 10  is a depiction of a light source mounted within a camera control unit. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an advantageous embodiment of the video imaging system  100 . A camera head  105  is provided having a multiplexer  110  for multiplexing image data and control signals. A camera control unit  115  is provided with a multiplexer  120  for receiving and processing the multiplexed signal from the camera head  105 . A command signal channel  125  is provided interconnecting camera head  105  and camera control unit  115 . The command signal channel  125  allows command signals to be sent from the camera control unit  115  to the camera head  105 . Command signals include any signal transmitted from the camera control unit to the camera head. A control signal channel  130  is provided interconnecting camera head  105  and camera control unit  115 . The control signal channel  130  allows control signals to be sent from the camera head  105  to the camera control unit  115 . Control signals include any signal transmitted from the camera head except image data, and may include signals such as: software programs, operating information, timing signal data, camera head identification information, camera use information and the like. An image data channel  135  is provided interconnecting camera head  105  and camera control unit  115 . The image data channel  135  allows image data to be sent from the camera head  105  to the camera control unit  115  for processing. 
     Through multiplexer  110  the control signal  130  and the image data  135  are transmitted down the same physical pair of wires, and the command signal  125  is transmitted on a second pair of wires. 
     Alternatively, for further cable size reduction, the command signal may also be multiplexed with the control signal and image data and therefore be transmitted down the same physical wire, thereby reducing the number of wires to one pair. It is well known in the art that multiplexers  110  and  120  may perform both multiplexing and de-multiplexing functions. The video imaging system utilizes a digital serial protocol such as Low-Voltage Differential Signaling. 
     Further, it will be apparent to those skilled in the art that additional pairs of wires may be supplied for image data, control signals, and command signals for future data carrying requirements as new systems become available. 
     A light source guide  140  is also furnished to provide illuminating light from light source  145 , through camera control unit  115 , to camera head  105 . 
     A single protective jacket  150  is also provided, for enclosing the command signal channel  125 , the control signal channel  130 , the image data channel  135 , the light source guide  140 , and any additional channels that may be utilized. 
       FIG. 2  illustrates an advantageous embodiment of the video imaging system  200 . A camera head  205  is provided having a cable  210 . In this embodiment, the cable  210  is permanently attached to the camera head  205 . However, it is contemplated that the cable  210  may also be detachably connected to the camera head  205 . The camera head  205  is equipped with an imager  215  for receiving photonic energy  220  reflected off an object (not shown). The camera head  205  is also equipped with a multiplexer  225  for multiplexing various signals generated by the camera head  205 . The various signals may include for instance: image data generated by the imager  215 , and control signals generated by the camera head  205 . In  FIG. 2 , the video imaging system  200  further comprises an endoscope  260  wherein the camera head  205  receives light  270  from the light source  255  and transmits the light  270  to the endoscope  260 . The light  270  is transmitted through the camera head  205 . The light  270  is transmitted from the camera head  205  to the endoscope  260  through an intermediate coupling  275  mounted to the camera head  205  and a cable  280  for connecting the intermediate coupling  275  and the endoscope  260 . 
     The cable  210  includes a light guide channel  230  for transmitting illuminating light to the camera head  205 . The cable  210  further includes data channels  235  for transmitting data to and from the camera head  205  and the CCU  240 . Four data channels  235  are depicted in  FIGS. 2 and 10 , however it will be obvious to one skilled in the art that fewer or more data channels  235  may be utilized. Image data and control signals are multiplexed in the camera head  205  by the multiplexer  225  for transmission along data channels  235 . One of the data channels  235  may be utilized for the multiplexed signal, or any number or combination of data channels  235  may be utilized. The cable  210  is also provided with a protective jacket  245 , encasing the light guide channel  230  and the data channels  235 .  FIG. 9  depicts a section of the camera head of  FIG. 2  showing four channels comprising eight electrical conductors  235   a - h.    
     In this advantageous embodiment it is contemplated that the CCU  240  may also be provided with a multiplexer  250  for multiplexing command signals, and for demultiplexing the image data and control signals sent from the camera head  205 . It is contemplated that multiplexers  225  and  250  may both provide both multiplexing the demultiplexing functions. A light source  255  is also provided for generating illuminating light for the transmission by the light guide channel  230  to the camera head  205 . The cable  210  is detachably connected to the CCU  240  as disclosed in  FIGS. 3-8 . 
     Referring to  FIGS. 3-8 , and particularly  FIG. 3 , a connector assembly for an endoscope assembly provides a connection between a camera head  305  and a source of light  310  through a CCU  315  having a front portion  330  and a rear portion  335 . A cable  320  extending from the camera head carries a light source guide and at least one wire pair transmitting electronic signals between the CCU and the camera head. A light source cable  325  extends from the light source  310  through the CCU and directly engages the cable  320  in the CCU. 
     Referring to  FIG. 4 , the connector assembly includes a plug  405  provided with a molded body  410 . A light connector  415  extends from a front surface  420  of the molded body  410 , whereas an electrical connection, which is mostly encased in the molded body  410 , has a keyed edge connector  425  projecting beyond the front surface  420 . As clearly seen in  FIG. 4 , the light connector  415  and the keyed edge connector  425  extending through the plug  405  are in a fixed spatial relationship. 
     The keyed edge connector  425  can be selected from a great variety of electrical connectors and, in the present case, is shown as a printed wiring board. The keyed edge connector  425  preferably terminates in the same plane as the light connector  415 . However, it is contemplated within the scope of the invention to provide an arrangement where the keyed edge connector  425  and the light connector  415  extend from the front surface  420  of the molded body  410  at different distances. Such structure provides for mating components of the receptacle to be similarly positioned with respect to one another. The light connector  415  is shown above the keyed edge connector  425 . However, it is possible to arrange the components in many different arrangements. It is however, advantageous to maintain a fixed spatial relationship as to the components in utilizing the various arrangements. 
     As further shown in  FIG. 4 , the molded body  410  has keying surfaces  430  for the plug as well as protection for the light connector  415  and the keyed edge connector  425  by extending from the front surface  420  beyond these connectors. The plug  405  is introduced through the front side  330  of the CCU ( FIG. 3 ) into a receptacle opening  435 . Each of the keying surfaces  430  has the geometry that allows the plug to enter the receptacle only in a predetermined spatial position. Exclusively, for illustrative purposes, each of the keying surfaces  430  of  FIG. 4  has two straight portions  440 ,  445  inclined with respect to one another. 
     The keying surfaces  430  are shaped and sized to place the plug  405  in a unique spatial position with respect to a receptacle  450  by extending complementary to an inner peripheral surface  455  of the opening  435  at the entry point for the plug  405 . The plug is advanced  460  into the receptacle  450  as indicated to provide engagement between light connector  415  and keyed edge connector  425  with optical component  505  and electrical component  510  respectively, as shown in  FIG. 5 . The position of the optical component  505  and electrical component  510  is a mirror image of the configuration of the light connector  415  keyed edge connector  425  respectively. Furthermore, a grounding plate  605 , seen in  FIG. 6 , is provided with a plurality of spaced-apart, resilient fingers  610  seen in  FIGS. 5 and 6 , which extend slightly above a bottom edge  515  of the opening  435  seen in  FIG. 4 . 
     The receptacle  450  has a housing  615 , as seen in  FIG. 6 , provided with a detachable front panel  620 . The front panel  620  has a front flange  625  lying flush with the front side  330  of the CCU when assembled. To provide a correct position of the front panel  620  with respect to the housing  615 , each of the sides  630  has an elongated recess  635  receiving a respective lug  640  formed on the housing  615 . 
     The housing  615  receives an optical connector component of the light source cable  325  extending through the rear portion  335  of the CCU and the light connector  415  and the keyed edge connector  425  of the plug  405 . A chamber  645  is sized so that the molded body  410  of the plug  405  extends at its full length into the receptacle  450  in an engaged position where the light connector  415  and the keyed edge connector  425  of the plug  405  engage respective components of the receptacle  450 . 
     The housing  615  is further provided with a collar  650  extending toward the rear portion  335  of the CCU  315  and receiving a guide element  705  as seen in  FIG. 7 , that linearly spans the distance between the rear portion  335  of the CCU  315  and the receptacle  450 . An inner end of the guide element  705  slides against the collar  650  and abuts a seat  805  as seen in  FIG. 8 , of the housing  615  of the receptacle  450 . An end of the light source cable  325  having an optical connection component extends beyond the guide element  705  and terminates in a rear wall  655  of the chamber  645 . Thus, the light source cable  325  is mounted within the receptacle  450  in a fixed spatial position and is aligned with the cable  320  after the molded body  410  of the plug  405  is registered with the opening  435  of the front panel  620 . 
     To provide an electrical connection between the camera head and the remaining CCU components, the receptacle  450  includes an electrical component  510  comprising a socket  660 . The socket  660  is in the same fixed spatial relationship with the optical component  505 . 
     To prevent the high intensity light from the source of light  310  from escaping the CCU  315 , the receptacle  450  is provided with a light deflector  665 , which is mounted to block the light from exiting the CCU  315  from the light source cable  325  when the plug  405  is withdrawn from the receptacle  450 . A bottom portion  675  bridges spaced apart walls  670  of the light deflector  665 . The deflector  665  is sized so that the keying surfaces  430  of the plug  405  contacts the bottom portion  675  as the plug  405  is advanced into the receptacle  450 . The light deflector  665 , which is pivotally mounted by means of a pin  680  extending between the spaced apart walls  670  and mounted on the housing  615  of the receptacle  450 , swings out of a light path. As the plug is withdrawn from the receptacle  450 , the light deflector  665  swings back into the light path to confine the light inside the CCU  315 . 
     To ensure that the pin  680  is not displaced from the housing  615 , a flange  685  provided on the front panel  620  covers a recessed portion  690 . Thus, the pin  680  may rotate between the bottom of the chamber  645  and the flange  685 . The chamber  645  is dimensioned to have the rear wall  655  juxtaposed with an edge  695  of the spaced apart walls  670  along the entire path of the light deflector  665 , as the plug  405  is being advanced or withdrawn from the receptacle  450 . Furthermore, the rear wall  655  has a curvature of the same radius as the edge  695 . As shown, the spaced apart walls  670  of the light deflector  665  have a triangular cross-section; however, any other cross-section allowing the light deflector  665  to swing into and out of the light path can be easily implemented. Only one advantageous embodiment is illustrated in the figures, however it will be apparent to those skilled in the art that many different embodiments may be possible for implementing the light deflector  665 . For instance, the light deflector may be rotatable, to rotate into the path of the light as shown, but it may also be slideable, or alternatively a sensor for sensing the presence of the plug  405  in the receptacle  450 , may act to disconnect, obstruct, attenuate or turn off the source of light  310  upon removal of the plug  405  from the receptacle  450 . Any of these or other methods may be utilized to prevent the light from escaping upon disconnection. 
     Although the invention has been described with reference to a particular arrangement of parts, features and the like, these are not intended to exhaust all possible arrangements or features, and indeed many other modifications and variations will be ascertainable to those of skill in the art.