Abstract:
A medical endoscope with sealed housing and receiving an electrically powered and/or controlled system, further comprising an installed light guide sealed against the ambience and fitted with electric/light (E/L) transducers at one end, is characterized in that a light/electricity (L/E) transducer is mounted at the other end of the light guide, one of the light guide ends being mounted inside the housing and the associated transducer being electrically connected to the electrical system.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an endoscope fitted with a sealed housing and an electrically powered and/or controlled system inside the housing, the endoscope including a light guide sealed against the outside and installed in the housing and fitted at one end with electricity/light transducers. 
     2. Description of Related Art 
     Endoscopes of this species are standard design today. The light guide typically is in the form of bundles of optic fibers. As a rule the light guide runs from a lateral, proximal input through the endoscope to a distal end of the endoscope. Light radiates from the light guide at the endoscope distal end surface to illuminate the field of view. A light-guide hook-up cable runs from the lateral input of the endoscope to a lamp, which illuminates the proximal end of the hook-up cable. The lamp in this instance constitutes the electricity/light (E/L) transducer. 
     Medical endoscopes have a sealed housing protecting the internal optical and electrical devices against exposure to liquids and vapors. Protection against vapors is required due to sterility-mandated steam-autoclaving. The sealing problems encountered in this design have been substantially solved as regards the installation of light guides. Illustratively, full sealing can be attained using soldered glass windows. 
     Electrical systems installed inside the endoscope, for instance video cameras, stepping motors for focusing etc., however must be powered electrically, that is, being fed with current. Accordingly, these internal electrical systems require external control lines to control their operation or to transmit signals to the outside, for instance control feedback or, in the case of a video camera, a video signal. 
     Aside from significantly unsatisfactory solutions such as integrated batteries constituting the power supply, or wireless signal transmission, the state of the art typically resorts to electric lines for power and for signal transmission. In addition to the already substantial sealing problems attending the light guides, additional sealing problems are introduced when using electric lines, connectors and the like. In practice, the sealing problems associated with the electric lines, connectors, etc are more difficult to overcome than those presented by the light guides. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to create an endoscope of the above species which eliminates or reduces the sealing problems present in the prior art. 
     In the invention, the power supply line is a light guide fitted at one end with an E/L transducer and, at the other end, with a light/electricity (L/E) transducer. Using an electric bulb as the E/L transducer and a power L/E transducer at the other end, namely inside the endoscope housing, the electric systems in said housing is then supplied with power. Using modulated E/L transducers such as modulated electric bulbs at one end of a light guide and an L/E transducer designed: for signaling purposes at the other end, a data transmission path is set up to act as a control line or as a signal transmission line for instance of the video signal. Appropriate electro-optic components are available economically and in appropriate dimensions. Electrical lines with their attendant feed through and sealing problems are avoided. The proven sealing techniques for light guides, for instance employing 100% tight windows, can be used. 
     Moreover, this technique offers the known advantage of reduced susceptibility to spurious electric radiation, which creates a significant problem in the vicinity of electro-surgical instruments. 
     The light guide used for transmission purposes may be installed in the endoscope housing separately and with its own feed through or access port. However, according to one features of the present invention, use is made of some of the cross-section of the illumination light guide. This space is already present for illumination and, using the proven sealing technique, may be retained to insert the guide into the endoscope and pass it through the endoscope. 
     The cross-sectional portion of the illumination light guide used as the light guide may terminate more shortly inside the endoscope for the purpose of being coupled to an L/E transducer. The illumination of the transducer may be carried out by the illuminating light source over the common, proximal cross-section. Advantageously, however, and according to another feature of the present invention, the light guide used for transmission purposes is installed over the full installation length together with the illuminating light guide. However, the light guide used for transmission purposes is apposed to the illuminating light guide and presented as a separate bundle of optic fibers that is accessible separately at both ends. 
     In further accordance with the present invention, the light guide can branch off the illuminating light guide at one or both ends and may advantageously run as far as the assembly site of the associated transducer. 
     In accordance with another feature of the present invention, the light source used for illumination in particular may serve as a high-power E/L transducer, that is, to feed current. However, the light source may also be modulated and therefore, optionally in superposition, it may be used for data transmission into the endoscope. 
     Alternatively, and in further accordance with the present invention, a separate light source may be used as the proximal E/L transducer. Such separate light source is of low power and in the form of an LED. This separate light source therefore serves to transmit signals very rapidly and at minimal power. 
     In further accordance with the present invention, a reverse signal flow is possible to communicate signals from the endoscope to the outside. Such signals may constitute, for instance, a feedback of control signals and/or transmission of video signals. 
     Using a plurality of transducer-equipped light guides, complex power supplies, control and data transmissions can be carried out using light guide technology. The light guides furthermore may be used for bi-directional signal transmission, optionally with additional power transmission. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     These and further features of the invention will be apparent with reference to the following description and drawing, which schematically shows a cross-section of an endoscope and a light source with control and receiving systems. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The FIGURE shows an endoscope  1 , an externally-mounted illuminating light source  2 , and a control and receiving system  3  configured in the area of the illuminating light source  2 . 
     The endoscope  1  is fitted with a closed housing  4  sealing against the surrounding environment. The housing receives an electric system including a video camera  5  and an electric stepping motor  6 . The stepping motor  6  is provided to move an adjusting bar  7  forward/rearward within the housing  4 . Movement of the adjustment bar  7  serves to adjust the video camera  5  relative to an objective lens  8 , which is mounted distally from the video camera and which observes the field of view in front of the distal end through a window  9  of the endoscope  1 . 
     A distal end zone of the endoscope  1  is occupied, except for the space taken up by the electric system  5 ,  6 , with an illuminating light guide  10 . The light guide  10  is in the form of a bundle of optic fibers. Due to sealing requirements, a distal end surface  11  of the light guide  10  terminates or ends behind the window  9 . Light radiates from the light guide distal end surface  11  through the window and into the viewing field. 
     The illuminating light guide  10  is guided proximally into a hook-up stub  12  which, in conventional manner, projects sideways or laterally from the housing  4  of the endoscope  1 . Inside the hook-up stub  12 , the illuminating light guide  10  terminates in front of a window  12   a  illustratively soldered in place and ensuring 100% sealing of the housing. Outside the stub  12 , the illuminating light guide  10  continues inside a hook-up cable with a sheath  13  which, by means of a socket  13   a , is plugged in the shown manner onto the hook-up stub  12 . The illuminating light guide  10  runs inside the hook-up cable as far as the illuminating light source  2  where its proximal end surface  14  is illuminated by an electric bulb  15  with reflector. The bulb  15  is powered through a conductor  17  by a power source  18 . 
     A light guide  19  is apposed to the illuminating light guide  10  and runs from it from the proximal end surface  14  into the housing  4  of the endoscope  1 . Within the endoscope housing, the light guide branches off or separates from the light guide  10 , and is connected to an L/E transducer  20 . The L/E transducer  20  is a power transducer, via electric conductors  21  and  22 , applies current to the video camera  5  and the stepping motor  6 . 
     A video signal from the video camera  5  is transmitted through an electric data line  23  and is coupled by an E/L transducer  24  to a light guide  25 . The light guide  25 , in turn, is apposed to the illuminating light guide  10  but laterally branches off or separates from the light guide  10  at the proximal end in front of the illumination source  2 . The proximal end of the light guide  25  is connected to an L/E transducer  26  that is linked, by a data line  27 , to a control system  28  used for control and image processing purposes. 
     Control signals controlling the video camera  5  are transmitted from the control system  28  through an electric line  29  to an E/L transducer  30 . Light signals from the E/L transducer  30  are transmitted through a light guide  31  which, in turn, travels together with the illumination light guide  10  as far as the inside of the housing  4  of the endoscope  1 . Within the housing  4 , the light guide  31  branches off from the illumination light guide  10  and is connected to an L/E transducer  32 . Electrical control signals from the L/E transducer are, via an electric line  33 , transmitted to the video camera  5 . 
     The electric motor  6  is controlled in a manner similar to that of the video camera. The control system  28  communicates electrical control signals through an electric line  33  to an E/L transducer  34 . Light control signals are transmitted from the E/L transducer  34 , via a light guide  35 , to an L/E transducer  36 . Electrical control signals are transmitted from the L/E transducer  36 , via an electric line  37 , to the electric motor  6 . 
     In a variation of the design shown above in relation to the connection stub  12 , the illumination light guide  10  also can run continuously from its distal end surface  11  to its proximal end surface  14 . If, in the shown and advantageous embodiment, the light guide  10  is designed with a detachable hook-up cable, then care must be taken at the interface of the window  12   a  that the illumination light guide  10  and the separate transmitting light guides  19 ,  25 ,  31  and  35 —which optionally also may consist of single fibers—each be supported in mutually opposite and flush manner at the interface in order to prevent cross-radiation from one light guide to another. The window  12   a  also may be designed in the form of a corresponding number of panes mutually separated by optical stops. 
     The illuminating light guide  10  also may be used for the transmission of the light to a device within the endoscope for purposes of communication or power. As shown in the Figure, it may terminate by means of a portion of the cross-section inside the housing  4  of the endoscope  1  into a distal end surface  11 ′. Light radiating from the distal end surface  11 ′ is coupled by deflecting mirrors  38  onto an L/E transducer  39  implementing power supply to an electric apparatus (not shown). 
     Moreover, a light guide  40  may be used to implement a transmission path into or out of the endoscope. The light guide  40  is installed separately from the illuminating light guide  10  and passes in a sealed manner through the housing  4 . A distal end of the light guide  40  is connected to a transducer  41  inside the housing  4 . 
     In addition to being illuminated by the electric bulb  15  at its proximal end surface  14 , a portion of the illuminating light guide  10  may be illuminated by a bulb  42  by means of deflecting mirrors  43  and  44 . The bulb  42  is powered by a power source  45 , for instance with modulated light. This modulated light for instance can be transmitted from the transducer  39  inside the endoscope housing  4  at the offset surface  11 ′ and be used to control an electric device (not shows). The path between the transducer  39  inside the housing  4  and the additional bulb  42  at the proximal end of the illuminating light guide also may be used in a reverse manner to transmit data from inside the endoscope to the outside.