Abstract:
An endoscope is provided having an observation port, a fluid supply pipe, a cap, a fluid ejection channel, and a direction adjustment protrusion. The observation port is provided at the distal end of the endoscope, and collects light reflected from an object. The fluid supply pipe transmits gas and/or liquid to the distal end. The cap blocks the distal end of the fluid supply pipe and is configured so that a partially enclosed semispherical space is created between the distal end of the fluid supply pipe and the inner surface of the cap. The fluid ejection channel has an outlet in the direction of the observation port, and extends from the edge of the opening at the distal end of the fluid supply pipe to the outlet and occupies the semispherical space inside the cap. The direction adjustment protrusion extends over the outlet in the lengthwise direction of the fluid ejection channel. When the outlet is projected outward toward the observation port, the plane of projection is parallel to the outlet and its lengthwise direction is parallel to the circumferential direction of the outlet. The direction adjustment protrusion is configured at the center of the outlet in the circumferential direction.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an endoscope with a nozzle that is provided at the distal end of the endoscope and ejects gas and/or liquid. 
     2. Description of the Related Art 
     An endoscope system includes both the endoscope and a processor. The endoscope is inserted into the body of an examinee so that an internal image can be photographed. The processor is provided outside of the examinee and processes the photographed image. A distal end of the endoscope has an observation port that collects light reflected by an object under observation, and a nozzle that ejects gas or liquid toward the observed object. Gas or liquid ejected from the nozzle removes foreign matter that has adhered to the observation port. 
     Nozzles that release fluids used for removing foreign matter that adhere to an observation port are disclosed. Japanese Patent No. 3493998 discloses a nozzle with a half-truncated cone-shaped pipe inside that can emit gas or liquid toward the distal end of an endoscope. Japanese Patent No. 3447577 discloses a compacted nozzle that has a tube connected to a fluid ejection port, and the thickness of the wall of the tube on the side of the fluid ejection port is increased. Japanese Patent Application Publication No. H09-201332 discloses a nozzle that moves back and forth so that it approaches an observation port at the moment when fluid is ejected. Japanese Patent No. 3845311 discloses an observation port that is raised from the distal end of an endoscope so as to form a truncated cone, so that fluid flows throughout the whole area of the observation port. 
     The art disclosed in Japanese Patent No. 3493998, however, increases fluid flow at the center of the stream ejected from the nozzle. Concerning Japanese Patent No. 3447577, however, the diameter of the flow ejected from the nozzle is approximately the same as the diameter of the outlet of the nozzle. Therefore, the diameter of the outlet of the nozzle must be approximately the same as the diameter of the observation port so that the whole surface of the observation port can be cleaned. The nozzle is not compacted in such case, therefore downsizing of an endoscope is inhibited. 
     Concerning Japanese Patent Application Publication No. H09-201332, however, the construction that allows the nozzle to move back and forth must be added to an endoscope, which inhibits downsizing of an endoscope. 
     Concerning Japanese Patent No. 3845311, concavities and convexities are formed at the distal end of an endoscope when the observation port is raised from the distal end of the endoscope to form a truncated cone. The concavities and convexities may collect unwanted mucous and tissue residue. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an endoscope that properly cleans an observation port and has a compact fluid-supplying nozzle. 
     An endoscope is provided having an observation port, a fluid supply pipe, a cap, a fluid ejection channel, and a direction adjustment protrusion. The observation port is provided at the distal end of the endoscope, and collects light reflected from an object. The fluid supply pipe transmits gas and/or liquid to the distal end. The cap blocks the distal end of the fluid supply pipe and is configured so that a partially enclosed semi spherical space is created between the distal end of the fluid supply pipe and the inner surface of the cap. The fluid ejection channel has an outlet in the direction of the observation port, and extends from the edge of the opening at the distal end of the fluid supply pipe to the outlet and occupies the semispherical space inside the cap. The direction adjustment protrusion extends over the outlet in the lengthwise direction of the fluid ejection channel. When the outlet is projected outward toward the observation port, the plane of projection is parallel to the outlet and its lengthwise direction is parallel to the circumferential direction of the outlet. The direction adjustment protrusion is configured at the center of the outlet in the circumferential direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects and advantages of the present invention will be better understood from the following description, with references to the accompanying drawings in which: 
         FIG. 1  is a schematic view of an endoscope and a processor according to the first embodiment; 
         FIG. 2  is a cutaway view from the side of the distal end of the endoscope; 
         FIG. 3  is a top view of the distal end of the endoscope from its axial direction; 
         FIG. 4  is a part of a cutaway view of a fluid-supplying nozzle and the observation port; 
         FIG. 5  is a front view of the nozzle; 
         FIG. 6  is a perspective view of the nozzle as seen diagonally from the upper right; 
         FIG. 7  is a perspective view of the nozzle as seen diagonally from the lower left; 
         FIG. 8  is a cross-sectional view of the nozzle cut along the line VIII-VIII in  FIG. 4 ; 
         FIG. 9  is a cross-sectional view of the nozzle cut along the line IX-IX in  FIG. 4 ; 
         FIG. 10  is a part of a cutaway view of a nozzle and an observation port according to the second embodiment; 
         FIG. 11  is a perspective view of an insertion pipe; 
         FIG. 12  is a perspective view of a guide; 
         FIG. 13  is a part of a cutaway view of a nozzle and an observation port according to the third embodiment; and 
         FIG. 14  is a perspective view of the nozzle. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention is described below with references to the embodiments shown in the drawings. 
     The endoscope system  100  according to the first embodiment is described below with references to  FIGS. 1-3 . Note that the alignment of each part shown in  FIG. 2  is different from that shown in  FIG. 3 , and a cutaway view of each part shown in  FIG. 2  is cut along a plane passing through the center axis of each part. 
     An endoscope system  100  has the endoscope  200  and a processor  300 . The endoscope  200  is inserted into the body of an examinee so that internal images can be photographed. The processor  300  is provided outside of the examinee and processes photographed images. 
     The endoscope  200  mainly comprises a flexible tube  240  that is inserted into the body of an examinee, an operating part  220  that is held by a user, and a connector  210  that connects the endoscope  220  to the processor  300 . A universal cable  230  connects the connector  210  to the operating part  220 . 
     The connector  210  has an air supply opening  211 , a liquid supply opening  212 , and a negative-pressure supply opening  213 . A fluid supply connector running out from a fluid supply tank is connected to the air supply opening  211  and to the liquid supply opening  212  so that gas, e.g. air, can be supplied to the air supply opening  211  and liquid, e.g. water, can be supplied to the liquid supply opening  212 . The fluid supply connector and the fluid supply tank are not shown in the figures. The air and water are supplied under predetermined pressures. A negative-pressure connector running out from a negative-pressure pump is connected to the negative-pressure supply opening  213  so as to supply negative pressure. The negative-pressure connector and the negative-pressure pump are not shown in the figures. 
     A gas supply tube  231  runs from the air supply opening  211  through the connector  210  and the universal cable  230  to the operating part  220 . Similarly, a liquid supply tube  232  runs from the liquid supply opening  212  to the operating part  220 , and a negative-pressure tube  233  runs from the negative-pressure supply opening  213  to the operating part  220 . 
     The operating part  220  comprises a forceps inlet  222  into which either forceps can be inserted or drugs injected, a fluid switch  110 , and a negative-pressure switch  150 . 
     The gas supply tube  231  and the liquid supply tube  232  that run from the connector  210 , and the fluid supply pipe  242  and a gas outlet tube  221  that run from the flexible tube  240  are all connected to the fluid switch  110 . The gas outlet tube  221  is connected to the fluid supply pipe  242  at the distal end of the flexible pipe  240 . The fluid switch  110  comprises a through hole that runs in the push direction. The through hole is connected to the gas supply tube  231  and the fluid supply pipe  242 . If the through hole is left open, gas escapes through the through hole from the gas supply tube  231 . If the through hole is closed, gas flows into the fluid supply pipe  242  through the gas outlet tube  221  from the fluid supply tube  231 . When a user depresses the fluid switch  110 , liquid flows to the fluid supply pipe  242  from the liquid supply tube  232 . According to these constructions, liquid or gas is ejected from the fluid supply outlet  243  that is provided at the distal end  246  of the flexible tube  240 . 
     The negative-pressure switch  150  is connected to a negative-pressure tube  233  that runs from the connector  210 . The negative-pressure switch  150  is a one-step switch, and negative pressure is channeled to a suction tube  241  from the negative-pressure tube  233  when a user depresses the negative-pressure switch  150 . According to these constructions, foreign matter are sucked into a suction inlet  245  provided at the distal end  246  of the flexible tube  240 . 
     A forceps tube  223  branches out from the suction tube and is connected to the forceps inlet  222 . A plug not shown in the figures is inserted into the forceps inlet  222 , and has a slit across the forceps inlet  222  so that gas, liquid, and foreign matter flow into the forceps tube  223  and do not spill out from the forceps inlet  222 . 
     A CCD unit  250 , the suction inlet  245 , a fluid outlet  243 , and a light lens  244  are provided at the distal end  246  of the flexible tube  240 . The fluid supply pipe  242  runs from the operating part  220  through the interior of the flexible tube  240  and is connected to the fluid outlet  243 . A first fluid nozzle  260  is connected to the opening of the fluid outlet  243 . The CCD unit  250  has an observation port  251 . The observation port  251  is exposed to the outside of the endoscope at its distal end  246 . The suction tube  241  runs from the operation part  220  through the interior of the flexible tube  240  and is connected to the suction inlet  245 . The light from the processor  300  passes through the light lens  244 , and illuminates an object. The CCD unit  250  photographs an object and then sends an image signal to the processor  300  through a signal cable. Note that the shape of the first fluid nozzle  260  has been simplified in  FIG. 2 . 
     The processor  300  sends light to the light lens  244  through a light fiber (not shown in figures), and receives the image signal so that an image can be shown on the display (not shown in figures). 
     The observation port  251 , two light lenses  244 , the suction inlet  245  and the first fluid nozzle  260  are all exposed on the end surface of the distal end  246 . The two light lenses  244  are provided, one on either side of the observation port  251 . The diameter of the fluid outlet  243  is smaller than the diameter of the observation port  251 . The outlet of the first fluid nozzle  260  faces the observation port  251 . The first fluid nozzle  260  is detachably attached to the endoscope  200 . 
     The construction of the CCD unit  250  is described hereinafter. 
     The CCD unit  250  mainly comprises the observation port  251 , which is a concave lens provided at its front end, a CCD  256 , which is an imaging sensor for photographing an object, and a base plate  257  on which peripheral circuitry of the CCD  256  is configured. These components are stored in a casing  258 . 
     An aperture plate  252  is provided on the backside of the observation port  251  and controls both the amount of light entering from the observation port  251  and the depth of field. A field lens  253  is provided at the backside of the aperture plate  252  and brings an object image into focus on the CCD  256 . A shield mask  254  and cover glass  255  are provided between the field lens  253  and CCD  256 . The shield mask  254  suppresses diffused reflection in a lens barrel to mitigate its influence on a photographed image. 
     The construction of the first fluid nozzle  260  is described hereinafter with references to  FIGS. 4-9 . Note that, a cutaway view of each part shown in  FIG. 4  is cut along a plane passing through the center axis of each part. 
     The first fluid nozzle  260  comprises a section of first insertion pipe  261  that is cylindrical, a first cap  262  that blocks one end of the first insertion pipe  261 , a first fluid ejection channel  263  that is provided between the first cap  262  and the end of the first insertion pipe  261 , and a first direction adjustment protrusion  264  that projects from the inner surface of the first fluid ejection channel  263 . 
     The shape of the first insertion pipe  261  is cylindrical such that its external and internal diameters are constant, so that its internal diameter is the same as the internal diameter of the fluid outlet  243  and the fluid supply pipe  242 , and its external diameter is larger than the internal diameter of the fluid outlet  243  and the fluid supply pipe  242 . A part of the opening of the distal end of the first insertion pipe  261  is U-shaped to form a U-shaped channel. 
     The first cap  262  is integrally attached to the end surface of the distal end of the first insertion pipe  261  so as to block the opening of the distal end of the first insertion pipe  261  and create a partially enclosed space at the end of the section of first insertion pipe  261 . 
     The first cap  262  is dome-shaped, and the thickness of its wall is the same as the thickness of the wall of the first insertion pipe  261 . The center of the top of the dome is flat along the axis of the dome, so as to form a plane. In the first cap  262 , the surface facing the fluid outlet  243  is the cap ceiling surface of the first cap  262 , and the surface connecting the ceiling surface to the inner surface of the first insertion pipe  261  is the cap side surface of the first cap  262 . The first fluid ejection channel  263  is formed so as to run through the cap side surface and open along the radial direction of the first cap  262 . 
     The first fluid ejection channel  263  is formed between a canopy extending from the first cap  262  and the U-shaped channel of the first insertion pipe  261 , and is surrounded by a ceiling surface extending from the cap ceiling surface, a side surface extending from the side surface of the dome shape, and a bottom surface extending from the U-shaped portion of the first insertion pipe  261 . The canopy has a U-shaped cross section and extends radially outward from the first cap  262 . 
     The width of the first fluid ejection channel  263 , i.e. in the direction parallel to the end surface of the section of first insertion pipe  261 , is longer than the height of the first fluid ejection channel  263 , i.e. in the direction orthogonal to the end surface of the first insertion pipe  261 . The width of the first fluid ejection channel  263  is shorter than the diameter of the observation port  251 . On the projected plane that is parallel to the outlet of the first fluid ejection channel  263 , when the first fluid ejection channel  263  faces toward the observation port  251 , the width of the first fluid ejection channel  263  is parallel to the width of the projected plane encompasses the diameter of the observation port  251 . 
     The distance between two side walls that are the side surfaces of the first fluid ejection channel  263  increases with increasing distance from the first cap  262 . In other words, the first fluid ejection channel  263  gradually become wider the further it is from the first cap  262 . The width of the first fluid ejection channel  263  is less than the diameter of the observation port  251 . 
     The first direction adjustment protrusion  264  projects outward from the top of the first cap  262  and forms an overhang over the first fluid ejection channel  263  that extends radially outward from the axis of the first insertion pipe  261 . The first direction adjustment protrusion  264  is provided along the center of the first fluid ejection channel  263 . The first direction adjustment protrusion  264  does not make contact with the bottom of the first fluid ejection channel  263 , so that a space is created between the bottom of the first fluid ejection channel  263  and the first direction adjustment protrusion  264 . The projecting length of the first direction adjustment protrusion  264  extends the farthest downward at the outlet, i.e. at the opening of the first fluid ejection channel  263 , and it is shorter the closer it is to the first cap  262 . The ceiling and the first direction adjustment protrusion  264  are continuously connected by a rounded surface. 
     When gas or liquid, e.g. water or air, passes through the fluid supply pipe  242 , water or air traveling through the first insertion pipe  261  collide with the ceiling of the first cap  262  before entering the first fluid ejection channel  263 . Water or air is deflected toward both nearby side walls of the first fluid ejection channel  263  and flow along the side surfaces of the first fluid ejection channel  263 . Therefore, the flow of water or air flowing out from the first fluid ejection channel  263  expands in the width direction of the first fluid ejection channel  263 . 
     The flow of water or air deflected by the ceiling of the first fluid ejection channel  263  collides with the first direction adjustment protrusion  264  so that it is split by the first direction adjustment protrusion  264  and expands in the direction of width of the first fluid ejection channel  263 . As described hereinbefore, a space between the bottom of the first fluid ejection channel  263  and the first direction adjustment protrusion  264 . Water or air flowing in the space travels in the extending direction of the first fluid ejection channel  263 . Therefore, the flow that is created from a fluid that passes underneath the first direction adjustment protrusion  264  when it exits through the outlet of the first fluid ejection channel  263  travels flat along the plane of the surface of the distal end of the first insertion pipe  261  as it moves toward the observation port  251 . The first fluid nozzle  260  creates a flow that expands in the lengthwise direction after it is ejected from the first fluid ejection channel  263  to create a wide-ranging uniform water current or air flow that travels flat along the plane of the surface of the distal end of the first insertion pipe  261 . 
     The first fluid nozzle  260  creates a straight flow that ejects from the first fluid ejection channel  263  before expanding in the width direction of the first fluid ejection channel  263 , so as to create a uniform water current or air flow over a wide range. 
     According to such constructions, a uniform water current or air flow is created over a wide range when the first fluid nozzle  260  is miniaturized, so that the first fluid nozzle  260  does not come into the angle of view of the CCD  256 , and illumination light does not influence a photographed image by reflection off of the first fluid nozzle  260 . Water or air is directed toward the observation port  251  when the ejecting direction of the first fluid nozzle  260  is slightly out of alignment with the regular alignment of the assembly. 
     Uneven surfaces are not created on the outer surface of the first fluid nozzle  260 , so that foreign matter does not adhere to the endoscope  200 . 
     The construction of the endoscope system  100  according to the second embodiment is described hereinafter with reference to  FIGS. 10-12 . The constructions of the second embodiment that are similar to the first embodiment have the same numeral applied and their descriptions have been omitted. Note that, a cutaway view of each part shown in  FIG. 10  is on a plane passing through a center axis of each part. 
     The constructions of the endoscope  200  and the processor  300  are similar to the first embodiment; however, the shape of the fluid nozzle differs to the first embodiment. Therefore, the second fluid nozzle  360  according to the second embodiment is described hereinafter. 
     The second fluid nozzle  360  comprises a second of insertion pipe  361 , which is substantially cylindrical, and a guide  362 . 
     The second insertion pipe  361  is formed by resin molding and has cylinder-shaped outer lateral surface. The diameter of the outer lateral surface is greater than the internal diameter of the fluid outlet  243 . 
     The inner lateral surface of the second insertion pipe  361  comprises an upper inner surface  363  and a lower inner surface  364 . When the second fluid nozzle  360  is attached to the endoscope  200 , the upper inner surface  363  is located near the distal end and the lower inner surface  364  is located near the proximal end. 
     The upper inner surface  363  has a shape that is formed by cutting a cylinder with a plane that is parallel to the axis of the cylinder, so that the upper inner surface  363  is a semicircle formed by a curved surface that is a part of the cylinder and a rectangle plane. The cross sections of the upper inner surface  363  cut by planes orthogonal to the axis are the same. The upper inner surface  363  take on a tunnel shape at the distal end of the second insertion pipe. The tunnel shape is formed by an arc that is a part of the curved surface of the cylinder and a chord that is a part of a rectangular plane. 
     The lower inner surface  364  has a shape that is formed by cutting a cylinder with a plane that is not parallel to the axis of the cylinder, so that the lower inner surface  364  is formed by a curved surface that is a part of the cylinder and a trapezoidal plane. The long side of the trapezoid overlaps one side of the rectangle that forms the upper inner surface  363 . The short side of the trapezoid is located on the proximal end of the second insertion pipe  361 . The curved surface of the upper inner surface  363  and the lower inner surface  364  has the same diameter and forms a continuous curve. In other words, at the section where the upper inner surface  363  and the lower inner surface  364  are joined together, the cross sections of the upper inner surface  363  and the lower inner surface  364  cut by a plane perpendicular to the axis of the cylinder are the same. The cross sections of the upper inner surface  363  cut by planes orthogonal to the axis are the same. The lower inner surface  364  takes on a tunnel shape at the proximal end of the second insertion pipe. The tunnel shape is formed by an arc that is a part of the curved surface of the cylinder and a chord that is a part of a rectangular plane. The cross sections of the lower inner surface  364  cut by planes orthogonal to the axis are homothetic. 
     The second direction adjustment protrusion  365  is provided on the distal end surface of the second insertion pipe  361 . The shape of the second direction adjustment protrusion  365  is a combination of a truncated cone and a cylinder that are connected so that their axes coincide with one another, and then the truncated cone and the cylinder are bisected by a plane that includes both axes. The diameter of the shared surface of the truncated cone and the diameter of the shared surface of the cylinder are the same. The shared surface of the truncated cone is connected to the shared surface of the cylinder. 
     The plane of the second direction adjustment protrusion  365  that bisects both the truncated cone and the cylinder is the plane of the distal end surface of the second insertion pipe  361 . Therefore, the axis of the second direction adjustment protrusion  365  is located on the distal end surface of the second insertion pipe  361 . The second direction adjustment protrusion  365  is located on the distal end surface of the second insertion pipe  361  so that the axis of the second direction adjustment protrusion  365  orthogonally intersects with the center of the chord of the upper inner surface  363 . The chord intersecting the axis appears on the distal end surface of the insertion pipe  361 . The top of the truncated cone is flush with the rectangle plane of the upper inner surface  363 . 
     The guide  362  is formed by sheet metal processing, and comprises the support  366  and the second cap  367 . 
     The support  366  has a shape that is formed by cutting a cylinder that has constant thickness with a plane that is parallel to the axis of the cylinder. Therefore, the support  366  is C-shaped on its cross-sectional plane that is orthogonal to the axis of the cylinder. The cross sections of the support  366  cut by planes orthogonal to the axis are the same. The diameter of the outer surface of the support  366  is substantially the same as the diameter of the upper inner surface  366 . 
     Concerning the support  366 , the distance between the axis of the cylinder and the plane cutting through the cylinder is shorter than the distance between the axis and the plane cutting through the upper inner surface  363 . In other words, the interior angle of the circular arc cut away from the support  366  is larger than the interior angle of the circular arc cut away from the upper inner surface  363 . Therefore, the cut surface of the support  366  does not make contact with the upper inner surface  363 . 
     The second cap  367  is dome-shaped and the thickness of its wall is the same as the thickness of the wall of the support  366 . The top of the dome shape is slightly flat along the axis of the dome, so as to form a plane. The second cap  367  is attached to the support  366  so as to block the opening of the distal end of the support  366  and create a partially enclosed space outside of the opening. In the side wall of the second cap  367 , a second fluid ejection channel  368  is created that opens outward in the radial direction. 
     The second fluid nozzle  360  is created by inserting the support  366  into the upper inner surface  363 . The construction of the guide  362  inserted into the second insertion pipe  361  is described hereinafter. 
     The second fluid ejection channel  368  is formed between a canopy extending from the second cap  367  and the distal end surface of the second insertion pipe  361 . The canopy has a U-shaped cross section and extends radially outward from the second cap  367 . The width of the second fluid ejection channel  368 , i.e. the length in the direction parallel to the end surface of the second insertion pipe  361 , is longer than the height of the second fluid ejection channel  368 , i.e. the length in the direction orthogonal to the end surface of second inserting pipe  361 . On the projected plane that is parallel to the outlet of the second fluid ejection channel  368 , when the second fluid ejection channel  368  faces toward the observation port  251 , the width of the projected plane encompasses the diameter of the observation port  251 . 
     The canopy is angled downward toward the distal end surface of the second insertion pipe  361 . In other words, the width of the second fluid ejection channel  368  decreases with increasing distance away from the second cap  367 . The distance between the two side walls of the canopy that are the side surfaces of the second fluid ejection channel  368  increases with increasing distance from the second cap  367 . In other words, the width of the second fluid ejection channel  368  increases with increasing distance from the second cap  367 . The width of the second fluid ejection channel  368  is less than the diameter of the observation port  251 . 
     The second direction adjustment protrusion  365  projects between the canopy and the distal end surface of the second insertion pipe  361 . The second direction adjustment protrusion  365  is provided at the center of the first fluid ejection channel  263  within the width of the second fluid ejection channel  368 . The second direction adjustment protrusion  365  does not make contact with the ceiling of the canopy, so that a space is created between the second direction adjustment protrusion  365  and the ceiling of the canopy. 
     When gas or liquid, e.g. water or air, is sent through the fluid supply pipe  242 , water or air flows through the second insertion pipe  361  to the guide  362 . And then, water or air collides with the cap ceiling of the second cap  367  and is deflected into the second fluid ejection channel  368 . Water or air flowing near the center of the second fluid ejection channel  263  is channeled along the side walls of the canopy. Therefore, water or air flowing out from the second fluid ejection channel  368  expands in the direction of the width of the second fluid ejection channel  368 . 
     Water or air flowing near the center of the second fluid ejection channel  368  separates when it collides with the second direction adjustment protrusion  365  before expanding in the direction of the width of the second fluid ejection channel  368 . As described hereinbefore, a space is created between the ceiling of the canopy and the second fluid ejection channel  365 . Water or air flowing in the space straightly travels in the extending direction of the second fluid ejection channel  368 . Therefore, the straight flow is created and ejected from the second fluid ejection channel  368 . 
     The second fluid nozzle  360  creates a straight flow that ejects from the second fluid ejection channel  368  before expanding in the width direction of the second fluid ejection channel  368 , so as to create a uniform water current or air flow over a wide range. 
     According to such constructions, a uniform water current or air flow is created over a wide range when the second fluid nozzle  360  is miniaturized, so that the first fluid nozzle  360  does not come into the angle of view of the CCD  256 , and a photographed image is not influenced by reflection off of the second fluid nozzle  360 . Water or air is directed toward the observation port  251  when the ejecting direction of the second fluid nozzle  360  is slightly out of alignment with the regular alignment of the assembly. 
     The second direction adjustment protrusion  365  can be replaced by replacing the second insertion pipe  361  because the second insertion pipe  361  is integrally molded using resin with the second direction adjustment protrusion  365 , which allows for easy maintenance of the endoscope  200 . 
     The production of the guide  362  is less complicated and less expensive than processing by cutting because the guide is made by sheet metal processing. The second direction adjustment protrusion  365  is formed on the second insertion pipe  361 , so that uneven surfaces are not created on the outer surface of the canopy and foreign matter does not adhere to the endoscope  200 . 
     Note that, the second insertion pipe may be made by other processing methods. 
     The second direction adjustment protrusion  365  may be formed directly on the distal end surface of the endoscope  200  without the second insertion pipe  361 . 
     The guide may be made by another processing method other than sheet metal processing. 
     The height of the second fluid ejection channel  368  may not increase with increasing distance from the second cap  367 . In other words, the height of the second fluid ejection channel  368  may be constant from the height of the second cap  367 . 
     The construction of the endoscope system  100  according to the third embodiment is described hereinafter with reference to  FIGS. 13 and 14 . The constructions of the third embodiment that are similar to the first embodiment have the same numeral applied and their descriptions have been omitted. Note that, a cutaway view from the side of each part shown in  FIG. 13  is on a plane passing through a center axis of each part. 
     The constructions of the endoscope  200  and the processor  300  are similar to the first embodiment; however, the shape of the fluid nozzle is different from the first embodiment. Therefore, the third fluid nozzle  460  according to the third embodiment is described hereinafter. 
     The third fluid nozzle  460  is made by forming a tube that comprises a third insertion pipe  461 , a third cap  462 , and a third fluid ejection channel  463 . 
     The third insertion pipe  461  has a cylinder-shaped outer lateral surface. The diameter of the outer lateral surface is greater than the internal diameter of the fluid outlet  243 . The inner lateral surface of the third insertion pipe  461  comprises an upper inner surface  466  and a lower inner surface  467 . When the third fluid nozzle  460  is attached to the endoscope  200 , the upper inner surface  466  is positioned near the distal end, and the lower inner surface  467  is located near the proximal end. 
     The upper inner surface  466  is tapered so that its cross-sectional area decreases the closer it is to the distal end. The lower inner surface  467  is the interior surface of a cylinder. 
     The third cap  462  is made by bending a tube so as to make a continuous arc from the third insertion pipe  461  that blocks the opening at the distal end of the third insertion pipe  461  and creates a partially enclosed space at the end of the opening. The end of the bended tube configured similar to a  FIG. 8  lying on its side that has two ellipses instead of two circles as its end shapes. 
     The shape of the third fluid ejection channel  463  is similar to an elliptical tunnel that includes a ceiling that extends down from the third cap  462  and is integrated with rounded sidewalls that extend further down and are integrated with a floor at the bottom of the tunnel. 
     The width, i.e. the length of the third fluid ejection channel  463  in the direction parallel to the end surface of the third insertion pipe  461  is longer than the height, i.e. the length of the third fluid ejection channel  463  in the direction orthogonal to the end surface of the third insertion pipe  461 . The width of the third fluid ejection channel  463  is shorter than the diameter of the observation port  251 . On the projected plane that is parallel to the outlet of the third fluid ejection channel  463 , when the third fluid ejection channel  463  faces toward the observation port  251 , the width of the projected plane encompasses the diameter of the observation port  251 . 
     In the center of the ceiling, the third direction adjustment protrusion  464  projects downward into the third fluid ejection channel  463 . In the center of the floor, the fourth direction adjustment protrusion  465  projects upward into the third fluid ejection channel  465 . The third direction adjustment protrusion  464  does not make contact with the fourth direction adjustment protrusion  465 , so that a space is created between the third direction adjustment protrusion  464  and the fourth direction adjustment protrusion  465 . The downward and upward projecting lengths of the third and fourth direction adjustment protrusions  464  and  465 , respectively, are longest at the outlet, i.e. the opening of the third fluid ejection channel  463 , and are shortest closest to the third cap  462 . 
     When gas or liquid, e.g. water or air, is sent through the fluid supply pipe  242 , water or air collide with the cap ceiling of the third cap  462  of the third insertion pipe  461 , and is directed into the third fluid ejection channel  463 . Water or air flowing near the center of the third fluid ejection channel  463  collide with the third direction adjustment protrusion  464  and the fourth direction adjustment protrusion  465  so that it becomes split by the third and fourth direction adjustment protrusions  464  and  465 , and expands in the direction of width of the third fluid ejection channel  463 . As described hereinbefore, a space is created between the third direction adjustment protrusion  464  and the fourth direction adjustment protrusion  465 . Water or air flowing in the space goes straight along the extending direction of the third fluid ejection channel  468 . Therefore, the straight flow is created that ejects directly from the third fluid ejection channel  463 . 
     The third fluid nozzle  460  creates flow by ejecting fluid directly from the third fluid ejection channel  463 , and the flow extending in the direction of width of the third fluid ejection channel  463  creates uniform water current or air flow over a wide range. 
     According to such constructions, uniform water current or air flow is created over a wide range when the third fluid nozzle  460  is miniaturized, so that the third fluid nozzle  460  does not come into the angle of view of the CCD  256  and illumination light does not influence a photographed image by reflection off of the third fluid nozzle  460 . Water or air is directed toward the observation port  251  when the direction of ejection of the third fluid nozzle  460  is slightly out of alignment with the regular alignment of the assembly. 
     Note that, the imaging sensor is not limited to the CCD  256 . 
     Although the embodiment of the present invention has been described herein with references to the accompanying drawings, obviously many modifications and changes may be made by those skilled in the art without departing from the scope of the invention. 
     The present disclosure relates to subject matter contained in Japanese Patent Application No. 2009-190978 (filed on Aug. 20, 2009), which is expressly incorporated herein, by reference, in its entirety.