Abstract:
Provided is an endoscope apparatus which is equipped with an endoscope including an object lens, a distal end portion and a handling section, a heat-producing device being incorporated into the distal end portion. The endoscope apparatus includes: a cleaning system which transiently discharges a cleaning liquid toward the object lens to clean the object lens; a cooling system which refluxes a coolant in the distal end portion to cool the heat-producing device; a liquid sending system, installed outside the endoscope, for supplying the cleaning liquid and the coolant; and a liquid-sending pressurizing system shared between the cleaning liquid and the coolant.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2010-120493 filed on May 26, 2010; the entire contents of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an endoscope apparatus. 
         [0004]    2. Description of the Related Art 
         [0005]    In association with sophistication in the capabilities of endoscope apparatuses, the quantity of heat produced at the distal end of an endoscope is on the increase. Accordingly, a technique of refluxing fluid in the distal end to provide cooling for the same has been desired. An endoscope apparatus equipped with such a distal-end cooling system is disclosed in, e.g., Japanese Published Patent Application Publication No. 2007-7322. 
         [0006]    The endoscope apparatus disclosed in Japanese Published Patent Application Publication No. 2007-7322 will be hereinafter discussed with reference to  FIG. 2 .  FIG. 2  shows a configuration of a conventional endoscope apparatus. In the endoscope apparatus shown in  FIG. 2 , tubes (supply and return channels) through which a coolant circulates at all times are installed in an endoscope insertion portion  901 . The coolant circulates through these tubes via a pump  922  that is installed in a handling section  921  to thereby provide cooling for an LED installed in an distal end body  903 . In addition, the handling section  921  is connected to a power supply  925  via a universal cord  923 . The power supply  925  is connected to a monitor  929  via a video processor  927  and also to a suction bottle  932  via a suction pump  931 . 
         [0007]    However, in the above-described conventional endoscope apparatus, the pump  922  is newly incorporated into the handling section  921  of the endoscope, which has been a cause of an increase in production cost, when compared with an endoscope apparatus having no cooling system at the distal end. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention has been made in view of the foregoing circumstances, and an object of the present invention is to provide an endoscope apparatus which is devised to be capable of minimizing the increase in production cost though having a distal-end cooling system. 
         [0009]    To solve the above-described problem and achieve the object mentioned above, according to the present invention, there is provided an endoscope apparatus which is equipped with an endoscope including an object lens, a distal end portion and a handling section, a heat-producing device being incorporated into the distal end portion. The endoscope apparatus includes a cleaning system which transiently discharges a cleaning liquid toward the object lens to clean the object lens, and a cooling system which refluxes a coolant in the distal end portion to cool the heat-producing device. The endoscope apparatus further includes a liquid sending system, installed outside the endoscope, for supplying the cleaning liquid and the coolant, and a liquid-sending pressurizing system shared between the cleaning liquid and the coolant. 
         [0010]    In the endoscope apparatus according to the present invention, it is desirable that the cleaning liquid and the coolant be supplied to the endoscope from the liquid sending system through a common liquid supply tube. 
         [0011]    In the endoscope apparatus according to the present invention, it is desirable that liquid supplied to the endoscope through the common liquid supply tube be bifurcated inside the endoscope to flow into a cleaning liquid sending tube and a coolant sending tube through which the cleaning liquid and the coolant are delivered to the distal end portion, respectively, wherein the cleaning liquid is transiently discharged as needed via a valve installed in the handling section, and wherein the coolant is sent to the distal end portion at all times while the endoscope apparatus is operated. 
         [0012]    In the endoscope apparatus according to the present invention, it is desirable that the endoscope apparatus performs one of the following two operations when the cleaning liquid is discharged: temporarily stopping delivery of the coolant; and decreasing a flow rate of the delivery of the coolant. 
         [0013]    In the endoscope apparatus according to the present invention, it is desirable that the endoscope apparatus temporarily suppress temperature rise of the heat-producing device when the cleaning liquid is discharged. 
         [0014]    In the endoscope apparatus according to the present invention, it is desirable that the endoscope apparatus temporarily suppress the temperature rise of the heat-producing device by a reduction in power supplied to the heat-producing device. 
         [0015]    In the endoscope apparatus according to the present invention, it is desirable that a liquid sending capability of the liquid sending system be temporarily increased when the cleaning liquid is discharged. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a schematic diagram showing the internal structure of a first embodiment of an endoscope apparatus according to the present invention; and 
           [0017]      FIG. 2  is a schematic diagram showing the configuration of a conventional endoscope apparatus. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    Embodiments of an endoscope apparatus according to the present invention will be discussed below in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited by the specific embodiments described herein. 
       First Embodiment 
       [0019]    A first embodiment of the endoscope apparatus will be hereinafter discussed with reference to  FIG. 1 .  FIG. 1  schematically shows the structure of the first embodiment of the endoscope apparatus. 
         [0020]    An endoscope  101  of the endoscope apparatus is provided, at a distal end side and a proximal end side, with a distal end portion  102  and a handling section  103 , respectively. The endoscope  101  is provided inside the distal end portion  102  with an object lens  104  and heat-producing electronic components (heat-producing devices) not shown in the drawings such as an image pickup unit and an illumination LED (light-emitting diode). The endoscope apparatus is provided outside the endoscope  101  with a controller  105 , a water tank  106 , a compressor  107  (liquid sending system, pressurizing system) and a drain tank  108 . The water tank  106  contains a cleaning liquid and a coolant, the compressor  107  operates to send the cleaning liquid and the coolant to the endoscope  101  by applying pressure to the water tank  106 , and the drain tank  108  holds drainage discharged from the endoscope  101 . 
         [0021]    Although water is used as a cleaning liquid and a coolant in the first embodiment of the endoscope apparatus, any other liquid can be used instead. 
         [0000]    The controller  105  and the endoscope  101  are electrically connected to each other via a bundle of power/signal transmission cables  109 . The bundle of power/signal transmission cables  109  is connected to the handling section  103  of the endoscope  101 . The controller  105  is connected to the heat-producing electronic components, which are installed inside the distal end portion  102 , via electrical wiring (not shown) installed inside the endoscope  101 . In addition, the controller  105  and the compressor  107  are electrically connected to each other via a bundle of power/signal transmission cables  110 . 
         [0022]    The endoscope apparatus is provided with a common liquid supply tube  111  through which both the cleaning liquid and the coolant flow. The common liquid supply tube  111  is drawn out from the water tank  106  to be connected to the endoscope  101  via a liquid supply tube connector  112  provided on the handling section  103 . In the interior of the handling section  103 , the common liquid supply tube  111  that is connected to the endoscope  101  via the liquid supply tube connector  112  is bifurcated at a branch portion  113  into two liquid sending tubes: a cleaning liquid sending tube  114  and a coolant sending tube  115 . 
         [0023]    The cleaning liquid sending tube  114  is connected to a cleaning nozzle  116  at the distal end portion  102 . A valve  117  is installed in a portion of the cleaning liquid sending tube  114  in the handling section  103 . The valve  117  is opened and closed by operating a valve switch (not shown) provided on the handling section  103 . 
         [0024]    The coolant sending tube  115  is connected to one end of a flow channel  118  provided in the distal end portion  102 , and the other end of the flow channel  118  is connected to the distal end of a coolant discharge tube  119 . The coolant discharge tube  119  is installed in the endoscope  101  to extend therethrough toward the handling section  103 , and the proximal end of the coolant discharge tube  119  is connected to one end of an external coolant discharge tube  121  via a connector  120  provided on the handling section  103 . The external coolant discharge tube  121  is connected at the other end thereof to the drain tank  108 . 
         [0025]    The endoscope apparatus is provided with an external air supply tube  122  which is connected to the water tank  106  in addition to the common liquid supply tube  111 . In the case where the liquid contained in the water tank  106  is pressurized downwards from above by the compressor  107  as shown in  FIG. 1 , the common liquid supply tube  111  is connected to the bottom of the water tank  106  or a portion of the water tank  106  in the vicinity of the bottom thereof, and an end of the external air supply tube  122  is connected to the top of the water tank  160  or a portion of the water tank  160  in the vicinity of the top thereof. 
         [0026]    The other end of the external air supply tube  122  is connected to a connector  123  provided on the handling section  103 , thereby being connected to an internal air supply tube  124 . The internal air supply tube  124  is installed in the endoscope  101  to extend therethrough toward the distal end portion  102 . In addition, the internal air supply tube  124  is coupled (joined) to the cleaning liquid sending tube  114  at a joint  125  formed in the vicinity of the distal end portion  102 . In addition, a valve  126  is installed in a portion of the internal air supply tube  124  in the handling section  103 . The valve  126  is opened and closed by operating a valve switch (not shown) provided on the handling section  103 . 
         [0027]    Operations of a cooling system of the endoscope apparatus for cooling the aforementioned heat-producing electronic components, which are installed inside the distal end portion  102 , will be discussed hereinafter. 
         [0028]    When the endoscope apparatus enters an operating state, the electronic components inside the distal end portion  102  enter operating states thereof and the compressor  107  starts operating. This causes water in the water tank to flow into the flow channel  118  through the common liquid supply tube  111  and the coolant sending tube  115  to thereby provide cooling for the distal end portion  102 . The cooling water as a coolant flown into the flow channel  118  in the distal end portion  102  is discharged into the drain tank  108  through the coolant discharge tube  119  and the external coolant discharge tube  121 . The flow of the coolant into the flow channel  118  in this way provides cooling for the entirety of the distal end portion  102 , which makes it possible to suppress temperature rise of the heat-producing electronic components installed in the distal end portion  102 . Here, if the endoscope is in a viewing state other than a state of cleaning the object lens  104 , the valve  117  is in the closed state and thus water in the water tank  106  flows solely into the coolant sending tube  115 , so that no water drains out of the cleaning nozzle  116  through the cleaning liquid sending tube  114 . 
         [0029]    Next, operations of a cleaning system for cleaning the object lens  104 , and operations of the cooling system during the operation of the cleaning system will be discussed hereinafter. 
         [0030]    When mucus on the observation site or the like causes a smear on the object lens  104  during observation, the endoscope operator operates a valve switch (not shown) to open the valve  117 . With this opening of the valve  117 , water in the water tank  106  is discharged therefrom not only toward the coolant sending tube  115  but also toward the object lens  104  from the tip of the cleaning nozzle  116  via the cleaning liquid sending tube  114 , so that the water thus discharged from the cleaning nozzle  116  cleans the object lens  104 . This lens cleaning time is in the order of a few seconds. 
         [0031]    The change of the state of the valve  117  to the open state is communicated to the controller  105  via the bundle of power/signal transmission cables  109  during the cleaning operation for cleaning the object lens  104 . Thereupon, the controller  105  reduces the power supplied to one or more than one of the heat-producing electronic components incorporated into the distal end portion  102 , e.g., to the aforementioned illumination LED. 
         [0032]    In addition, upon completion of the operation for cleaning the object lens  104 , the controller  105  closes the valve  117  and sets the level of the power supplied to the aforementioned heat-producing electronic component or components, which is incorporated into the distal end portion  102 , back to the original setting. 
         [0033]    During the operation for cleaning the object lens  104 , a cleaning liquid is discharged from the cleaning nozzle  116  with the valve  117  open; therefore, the pressure for delivering a cleaning liquid toward the coolant sending tube  115  drops at the branch portion  113 , so that the flow rate of the coolant flown into the flow channel  118  reduces. This reduction may cause a decrease in the capability of cooling the distal end portion  102 . However, as described above, the temperature rise of the distal end portion  102  can be suppressed by a reduction in power supplied to the heat-producing electronic component or components incorporated into the distal end portion  102 . 
         [0034]    At this time, in the first embodiment of the endoscope apparatus, the quantity of reduction in power supplied to, e.g., the illumination LED can be set to a level not presenting an obstacle to an observation operation during the object-lens cleaning operation in a normal endoscopic examination or treatment even if the illuminance of the observation field of view decreases. 
         [0035]    As described above, in the first embodiment of the endoscope apparatus, both the capability of cleaning the object lens  104  and the capability of cooling the distal end portion  102  can be achieved with a simple configuration by supplying a coolant and a cleaning liquid via the common liquid supply tube  111  and the compressor  107  that are shared between the cooling system and the cleaning system. In addition, control of the power supplied to the heat-producing electronic component or components can suppress temperature rise of the distal end portion  102  that accompanies a reduction in the flow rate of the coolant during the discharge of the cleaning liquid. Accordingly, it is no longer required to install two independent compressors or pumps for supplies of the cooling liquid and the coolant, respectively. Additionally, to ensure a sufficient flow rate for both a coolant and a cleaning liquid at a time, a high-pressure compressor is usually required and tubes, pipes and others to be installed are usually required to be resistant to high pressure and increased in size; however, in the first embodiment of the endoscope apparatus, no high-pressure compressor is required, which makes it possible to prevent the system from becoming complicated and increasing in size. 
         [0036]    Modified embodiments of the first embodiment of the endoscope apparatus will be discussed hereinafter. 
         [0037]    The valve  117  can be replaced by a valve for switching between a cleaning liquid and a coolant to increase the discharge pressure of the cleaning liquid by shutting off the flow of the coolant with the valve during discharge of the cleaning liquid. Alternatively, during discharge of the cleaning liquid, power supply can be reduced by a reduction in frame rate of the image pickup unit, not by a reduction in quantity of the power supplied to the illumination LED. 
         [0038]    In addition, an arrangement in which a coolant tank and a cleaning liquid tank that are independent of each other are pressurized by a single compressor is possible. This arrangement is suitable for the case where it is desirable to use different types of liquids as a cleaning liquid and a coolant. In this case, however, the cleaning liquid and the coolant are supplied to the endoscope through independent liquid sending tubes. 
         [0039]    Additionally, although the branch portion  113  and the valve  117  are installed in the handling section  103  in the first embodiment of the endoscope apparatus, the present invention is not limited to this particular installation; for instance, each of the branch portion  113  and the valve  117  can be installed in any part of the endoscope  101 . In addition, it is possible that the branch portion  113  and the valve  117  be installed in the controller  105  so that liquid sending tubes (branch tubes) extending from the branch portion  113  are connected to the endoscope  101 . 
         [0040]    Additionally, the valve switches of the valves  117  and  126  can be installed in any part other than the handling section  103 . Additionally, the valves  117  and  126  can be operated not only by manually operating the valve switches by an endoscope operator but also automatically in response to a detection of the adherence of a smear on the object lens  104 . 
         [0041]    Additionally, although a reduction in power supply to one or more heat-producing electronic components such as the illumination LED is implemented as a measure to reduce the quantity of heat produced at the distal end portion  102  during the operation for cleaning the object lens  104  in the first embodiment of the endoscope apparatus, another measure can be implemented. For instance, it is conceivable, e.g., to reduce or stop the operating frequency or applied voltage of the image pickup unit or peripheral circuits incorporated into the distal end portion  102 . 
       Second Embodiment 
       [0042]    A second embodiment of the endoscope apparatus is identical in structure to the first embodiment of the endoscope apparatus except that the flow rate of a cleaning liquid is ensured with no reduction in the flow rate of a coolant by temporarily increasing the pressure of the compressor  107  when the valve  117  moves to the open state. 
         [0000]    The controller of the second embodiment of the endoscope apparatus controls the operation of the compressor  107  in a manner to increase the pressure to the water tank  106  upon detecting that the valve  117  moves to the open state. This control makes it possible to supply the same quantity of coolant as in the closed state of the valve  117  to the flow channel  118  through the coolant sending tube  115  even when the valve  117  moves to the open state. 
         [0043]    In this endoscope apparatus, the compressor needs an extra capacity, devices of the endoscope apparatus that are installed outside the endoscope increase in size, and an improvement in resistance to pressure is required for the tubes and pipes installed in the endoscope; however, there is a merit of not complicating the electrical control system since it is not required to control the power supplied to the electronic components installed inside the distal end portion  102  in accordance with changes in the open/closed states of the valve  117 . 
         [0044]    The other configurations, operations and effects are identical to those in the first embodiment of the endoscope apparatus. 
         [0045]    As can be understood from the foregoing, the endoscope apparatus according to the present invention is suitably used as an endoscope apparatus the distal end of which easily produces heat due to sophistication in the capabilities of the endoscope. 
         [0046]    The endoscope apparatus according to the present invention offers an effect capable of minimizing the increase in production cost though having a cooling system at the endoscope distal end.