Endoscope provided with a section for bending the endoscope

An endoscope is provided with a centering control section and a centering button. The centering control section is configured to control a bending mechanism in such a manner as to return a bendable portion to a neutral position where the bendable portion is substantially linear. The centering button is used for entering an instruction for controlling the centering control section. The endoscope is also provided with a personal computer configured to change the bend the bendable portion should have when the bendable portion is returned to the neutral position. The bend is changed in accordance with a bending characteristic variance the bendable portion may undergo in each bending direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2002-261748, filed Sep. 6, 2002, the entire contents of which are incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an endoscope inserted into a space to be inspected and used for observing the space.

2. Description of the Related Art

In general, an endoscope widely used for industrial purposes comprises a flexible insertion section, which is to be inserted into a space to be inspected. The insertion section includes a bendable portion, and this bendable portion can be bent in the vertical direction, in the horizontal direction or in any desired direction, i.e., a combination of the vertical and horizontal directions. A plurality of bending-operation wires (e.g., four wires) are attached to the bendable portion. The proximal end of each bending-operation wire extends toward the proximal portion of the insertion section. An operation section is coupled to the proximal end of the insertion section. The operation section includes a bending-operation mechanism, and the proximal ends of the bending-operation wires are coupled to this bending-operation mechanism.

The operation section includes an input device, such as a joystick. The bending-operation mechanism is driven and the bendable portion is bent, using the joystick. The joystick is provided with a stick whose proximal portion is pivotally supported by a pivot support. The stick is movable between a neutral position where it stands upright and a slanted position where it is slanted. When the stick is slanted in a direction at a desired angle, signals corresponding to the direction and angle of the stick are generated. The joystick outputs signals when operated, and the driving motor or other structural elements of the bending-operation mechanism are driven in accordance with the output signals. The bending-operation wires are pulled, accordingly. In this manner, the bendable portion is bent in association with the pulling movement of each bending-operation wire when the joystick is operated. (An example of this type of endoscope is disclosed, for example, in Jpn. Pat. Appln. KOKAI Publication No. 5-15486.)

In an endoscope of the above structure, the bending-operation wires are inserted in angle coils for protection, and in this state they are arranged in the interior of the tube of the insertion section. When the bending-operation wires are pulled, they slide along the inner surface of the angle coils. When the bendable portion is bent, there is inevitably a certain degree of resistance (e.g., frictional resistance) between the bending-operation wires and the angle coils. For this reason, even if the joystick is returned to the neutral position after the bendable portion is bent in a certain direction, it may happen that the operation force will not be transmitted fully to the bendable portion. In such a case, the bendable portion may not be restored into its substantially linear state, which corresponds to the neutral position of the stick.

In the conventional art, when the bendable portion is bent and then restored into the substantially linear state corresponding to the neutral position, the operator intentionally operates the stick in the direction opposite to that in which it has been slanted. By so doing, the bendable portion can be restored into the linear state corresponding to the neutral position.

Jpn. Pat. Appln. KOKAI Publication No. 5-15486 discloses a control means for detecting the degree to which a bendable portion is bent and controlling the time for which a driving mechanism is operated until the bendable portion is restored into the linear state.

The degree to which the bendable portion is operated in the direction opposite to that in which it has been slanted and the time for which the driving mechanism should be operated, are determined by parameters. The parameters are preset for a control circuit and represent a predetermined extent.

BRIEF SUMMARY OF THE INVENTION

An endoscope according to one aspect of the present invention comprises:

a flexible insertion section which is insertable into a space to be inspected, the insertion section including a bendable portion at a distal end thereof;

a bending mechanism located on a proximal side of the insertion section, the bending mechanism being configured to drive the bendable portion;

a centering control section configured to control the bending mechanism such that the bendable portion is returned to a neutral position where the bendable portion is substantially linear;

a centering instruction input section from which an instruction for controlling the centering control section is input; and

a return position adjustment section configured to vary the bend of the bendable portion when the bendable portion is returned to the neutral position, the return position adjustment section operating when the centering control section is operated and determining the bend in accordance with a bending characteristic difference the bendable portion has between bending directions.

When the bendable portion is restored from a bent state, the centering instruction input section is operated to input an instruction supplied to the centering control section. As a result, the centering control section controls the bending mechanism until the bendable portion returns to a neutral position where the bendable portion is substantially linear. By operating the centering control section, the return position adjustment section varies the bend of the bendable portion when the bendable portion is returned to the neutral position. The return position adjustment section determines the bend in accordance with a bending characteristic difference the bendable portion has between bending directions. Accordingly, centering with high precision is enabled for each bending direction.

The return position adjustment section includes: a recognition section configured to recognize a bending characteristic variance the bendable portion may undergo in each bending direction; and a bend-varying section configured to vary the bend the bendable portion should have when the bendable portion is returned to the neutral position, on the basis of a recognition result of the recognition section.

When the bendable portion is restored from a bent state, the recognition section of the return position adjustment section recognizes a bending characteristic variance the bendable portion may undergo in each bending direction. On the basis of a recognition result of the recognition section, the bend-varying section varies the bend the bendable portion should have when it is returned to the neutral position.

The centering instruction input section of the centering control section is connected to a parameter storage section. The parameter storage section stores parameters based on which a centering instruction signal is generated. When the centering instruction input section is operated, it outputs an instruction to generate a centering instruction signal and supplies it to the centering control section on the basis of a centering parameter stored in the parameter storage section.

The operation section includes a remote control. The remote control includes a joystick. The centering instruction input section includes a centering button located near the joystick of the remote controller. The centering button of the centering control section is connected to a parameter storage section. The parameter storage section stores parameters based on which a centering instruction signal is generated. When the centering button is operated, it outputs an instruction to generate a centering instruction signal and supplies it to the centering control section on the basis of a centering parameter stored in the parameter storage section.

The return position adjustment section includes a personal computer detachably attached to the endoscope. The personal computer is connected to the centering control section, and the parameters in the parameter storage section are directly changed by use of the personal computer in such a manner that the bend the bendable portion should have when it is returned to the neutral position is varied in accordance with a bending characteristic variance the bendable portion may undergo in each bending direction. Of the parameters, those parameters corresponding to the directions in which the bendable portion can hardly restore its original shape are increased.

The insertion section includes an internal channel inside, and the recognition section includes a photo-coupler configured to detect whether or not a treatment device is inserted in the internal channel.

The bend-varying section includes two parameter storage sections that store different centering parameters. The centering parameters are data representing how the bendable portion should operate when it is subject to a centering operation after being bent in a given direction. The two parameter storage sections are specifically a first parameter storage section and a second parameter storage section. The bend-varying section further includes a switch section interposed between the centering control section and the two parameter storage sections. The first parameter storage section stores data representing how the bendable portion should operate in each bending direction where the treatment device is not inserted in the internal channel. The second parameter storage section stores data representing how the bendable portion should operate in each bending direction where the treatment device is inserted in the internal channel. The switch section operates on the basis of a recognition result of the photo-coupler and switches the first and second parameter storage sections from one to the other so as to perform a centering operation.

An endoscope according to another aspect of the present invention comprises:

a flexible insertion section which is insertable into a space to be inspected, the insertion section including a bendable portion at a distal end thereof;

a bending mechanism located on a proximal side of the insertion section, the bending mechanism being configured to drive the bendable portion;

a recognition section configured to recognize a bending characteristic variance the bendable portion may undergo in each bending direction; and

a bend-varying section configured to vary a bend the bendable portion should have, on the basis of a recognition result of the recognition section.

When the bendable portion is restored from a bent state, the recognition section recognizes a bending characteristic variance the bendable portion may undergo in each bending direction. On the basis of a recognition result of the recognition section, the bend-varying section varies the bend of the bendable portion in such a manner that centering with high precision is enabled for each bending direction.

The recognition section includes a determination section configured to determine whether or not the bending characteristic has varied by detecting whether there is a treatment device channel through which a treatment device is inserted into the insertion section.

Based on the detection of the treatment device channel through which the treatment device is inserted into the insertion section, the determination section determines whether or not the bending characteristic has varied. Centering with high precision is therefore enabled for each bending direction.

The insertion section includes a treatment device channel into which the treatment device is inserted, and the recognition section includes a treatment device detecting section configured to determine whether or not the bending characteristic has varied by detecting a treatment device inserted into the treatment device channel.

With this configuration, the recognition section recognizes a state where a treatment device is inserted in the treatment device channel, a state where an external channel tube is attached to the outer portion of the insertion section, or a state where forceps are inserted through the external channel tube. Based on this recognition, appropriate parameters are determined, a bending characteristic variance is determined, and centering with high precision is enabled for each bending direction.

The bending mechanism includes operating wires used for bending the bendable portion, and a driving motor configured to pull the operating wires. The recognition section includes a determination section configured to make a determination based on the current value of the driving motor.

Whether or not the bending characteristic has been varied is determined by detecting the current value of the driving motor of the bending mechanism. Based on this determination, centering with high precision is enabled for each bending direction.

The bending mechanism includes operating wires used for bending the bendable portion, and a driving motor configured to pull the operating wires. The recognition section includes a determination section configured to make a determination based on the voltage applied to the driving motor.

Whether or not the bending characteristic has been varied is determined by detecting the voltage applied to the driving motor of the bending mechanism. Based on this determination, centering with high precision is enabled for each bending direction.

The bend-varying section includes an addition section configured to add digital signals to control signals used for bending the bendable portion. The digital signals are added on the basis of a recognition result of the recognition section when the bending characteristic the bendable portion has for each bending direction varies.

The insertion section includes an attachment portion to which an external channel for insertion of the treatment device is detachably attached, and the determination section includes an external channel detector used for determining whether or not the external channel is attached to the attachment portion.

The external channel detector includes a contact used for detecting the external channel.

The determination section includes a photo-coupler used for determining whether the treatment device is inserted into the treatment device channel.

DETAILED DESCRIPTION OF THE INVENTION

The first embodiment of the present invention will now be described with reference toFIGS. 1 through 10.FIG. 1shows an industrial endoscope apparatus1of the embodiment. The endoscope apparatus1is provided with an assembling unit2which integrally assembles the structural elements of an endoscope, and an endoscope storage case3in which the assembling unit2is removably stored.

As shown inFIG. 2A, the endoscope storage case3includes a box-shaped case main body3aand a cover3b. The case main body3ahas an open upper section. The open upper section can be closed with the cover3b. The cover3bis rotatably coupled to one edge of the open upper section of the case main body3aby means of a hinge (not shown).FIG. 1shows the state where the assembling unit2is stored in the endoscope storage case3, with the cover3bopen.

FIG. 2Bis an exploded perspective view of the assembling unit2of the endoscope apparatus1. The assembling unit2includes a scope section4, a fixing unit5and a storage section6. The scope section4, the fixing unit5and the storage section6are assembled together in a detachable manner.

The scope section4includes at least the following: an elongated flexible insertion section4awhich is to be inserted into a space to be inspected; an intermediate coupler4b; a universal cable4c; and a base unit4d(i.e., a section for driving the insertion section). The insertion section4ais located at the distal end and is provided with the following: a head4a1in which an observation optical system, an illuminating optical system, etc. are incorporated; a bendable portion4a2which can be operated remotely; and an elongated flexible tube4a3. The bendable portion4a2is located between the head4a1and the flexible tube4a3.

As shown inFIG. 3, an illumination window31of the illuminating optical system, an observation window32of the observation optical system, a distal-end opening34of an internal channel (a treatment device passage)33(shown inFIG. 8) of the insertion section4a, etc. are open in the distal end face of the head4a1.

As shown inFIG. 8, a light guide36, a signal line37, and a plurality of angle wires (operating wires)101a1to101a4(which are four in number in the present embodiment) are arranged inside the insertion section4a. The light guide36is an optical passage through which light is transmitted to the observation window31. The signal line37is connected, for example, to a CCD of the observation optical system. The four angle wires101a1to101a4are used for bending the bendable portion4a2.

In the present embodiment, angle wires101a1and101a2are used for vertical bending. The remaining angle wires101a3and101a4are used for horizontal bending. The bendable portion4a2of the insertion section4ais vertically bent by use of the two vertically-bending angle wires101a1and101a2, and is horizontally bent by use of the two horizontally-bending angle wires101a3and101a4. Using these four wires, the bendable portion4a2is bent upward, downward, rightward, leftward, or in any direction desired.

The angle wires101a1to101a4, which are arranged in the internal region of the tube of the insertion section4a, are inserted in angle coils101b1to101b4, for protection. The outer circumferential surface of the insertion section4ais covered with an outer blade4a4.

As shown inFIG. 3, the distal end of the intermediate coupler4bis coupled to the proximal end of the flexible tube4a3of the insertion section4a. The intermediate coupler4bcomprises a grip portion4b1. The grip portion4b1is taken hold of by the operator. At the rear end of the grip portion4b1, a channel port4b2and a coupler to the distal end of the universal cable4care juxtaposed. The channel port4b2has a forceps opening35(an opening at the proximal end) that communicates with an internal channel33. The internal channel33extends through the insertion section4ain the axial direction thereof. The coupler to the universal cable4cis slanted relative to the axial direction of the insertion section4a.

The light guide36, signal line37and four angle wires101a1to101a4extending from the insertion section4aare inserted into the interior of the universal cable4c.

The intermediate coupler4bhas an insertion section-protecting rubber portion38. The insertion section-protecting rubber portion38serves to prevent the insertion section4afrom being bent acutely. The intermediate coupler4bhas a universal cable-protecting rubber portion39. The universal cable-protecting rubber portion39serves to prevent the universal cable4cfrom being bent acutely.

As shown inFIG. 4A, the proximal end of the universal cable4cis coupled to a base unit4d. The base unit4dcomprises a unit case4d1, an electric bending device (a bending mechanism)51, an electric bending controller52for controlling the electric bending device51, a camera control unit (CCU)53(shown inFIG. 7), etc. These structural components are contained in the unit case4d1.

The electric bending device51comprises a pulling force transmission mechanism unit54, and two motor units55aand55bfor vertical and horizontal bending operations. The two motor units55aand55bare located under the pulling force transmission mechanism unit54.

Motor unit55acomprises an output shaft55a1, a motor section55a2serving as a driving source for generating a driving force, a decelerating gear section55a3, and a potentiometer104a. Likewise, motor unit55bcomprises an output shaft55b1, a motor section55b2serving as a driving source for generating a driving force, a decelerating gear section55b3, and a potentiometer104b. The decelerating gear sections55a3and55b3are made of gear trains (e.g., spur gear trains) for transmitting the driving forces of the motor sections55a2and55b2to the output shafts55al and55b1. The potentiometers104aand104bdetect rotations of the output shafts55al and55b1. The potentiometers104aand104bare arranged in parallel to the motor sections55a2and55b2, respectively, with the corresponding decelerating gear sections55a3and55b3being located therebetween.

The pulling force transmission mechanism unit54has an upper end attached to the upper end portion of the unit case4d1. The proximal end of the universal cable4cis coupled to the upper end portion of the pulling force transmission mechanism unit54. The two motor units55aand55bare installed in the lower region of the unit case4d.

As shown inFIGS. 6A and 6B, the pulling force transmission mechanism unit54comprises a unit case56. Two pulling force transmission mechanisms57aand57b, which correspond to the two bending directions of the bendable portion4a2, are provided inside the unit case56. One (57a) of the two pulling force transmission mechanisms57aand57bis shown inFIG. 5B. As shown inFIG. 6A, pulling force transmission mechanism57aincludes: a sprocket58afixed to the output shaft55a1of the vertically-bending motor unit55a; and a chain59aengaged with the sprocket58a. The output shaft55a1of the motor unit55ais of a double shaft type. In other words, the motor unit55ahas two output shafts extending in the opposite directions. The sprocket58ais attached to one of the output shafts55a1, and the potentiometer104ais provided at the other output shaft.

The proximal ends of two angle wires101a1and.101a2are coupled to the two ends of the chain59aby means of coupling members60a1and60a2, respectively. With this structure, the pulling force transmission mechanism57ashown inFIG. 5Binterlocks with the motor unit55a, thereby providing a vertically-bending driving mechanism51a.

When the vertically-bending motor unit55arotates the sprocket58a, the chain59aand the coupling members60a1and60a2are driven, and the vertically-bending angle wires101a1and101a2are pulled or loosened.

The other pulling force transmission mechanism57bis shown inFIG. 5A. As shown inFIG. 6A, pulling force transmission mechanism57bincludes: a sprocket58bfixed to the output shaft55b1of the horizontally-bending motor unit55b; and a chain59bengaged with the sprocket58b. The output shaft55b1of the motor unit55bis of a double shaft type. In other words, the motor unit55bhas two output shafts extending in the opposite directions. The sprocket58bis attached to one of the output shafts55b1, and the potentiometer104bis provided at the other output shaft.

The proximal ends of two angle wires101a3and101a4are coupled to the two ends of the chain59bby means of coupling members60a3and60a4, respectively. With this structure, the pulling force transmission mechanism57bshown inFIG. 5Ainterlocks with the motor unit55b, thereby providing a horizontally-bending driving mechanism51b.

When the horizontally-bending motor unit55brotates the sprocket58b, the chain59band the coupling members60a3and60a4are driven, and the horizontally-bending angle wires101a3and101a4are pulled or loosened.

With the structure described above, the vertically-bending motor unit55aof the electric bending mechanism51pulls the two vertically-bending angle wires101a1and101a2. Likewise, the horizontally-bending motor unit55bpulls the two horizontally-bending angle wires101a3and101a4. Hence, the bendable portion4a2can be bent in a vertical direction, in a horizontal direction or in any direction combined. When the bendable portion4a2is bent, the potentiometers104aand104bsense the rotated positions of the sprockets58aand58b. On the basis of sensing signals supplied from the potentiometers104aand104b, the electric bending controller52controls the positions of the angle wires101a1to101a4, thereby controlling the operation of bending the bendable portion4a2.

As shown inFIG. 7, the proximal end of the signal line37is connected to the camera control unit53. The distal end of the signal line37is connected to the CCD located inside the insertion section4a. Image data representing endoscopic observation images obtained by the CCD are converted into electric signals, and these electric signals are supplied to the camera control unit53through the signal line37.

As shown inFIG. 2B, a light guide connector4d2is projected from an end surface of the unit case4d1of the base unit4d. The proximal end of a light guide (not shown) extending from the universal cable4cis coupled to the light guide connector4d2.

A pair of attachment/detachment guides4d3, namely, upper and lower attachment/detachment guides, are provided on another side surface of the unit case4d1of the base unit4d. The guides4d3extend substantially in the horizontal direction. When the base unit4dand the fixing unit5are coupled, the guides4d3guide the movement of the base unit4d. A plurality of fixing members4d4are projected from the above-mentioned end surface of the unit case4d1. When the base unit4dand the fixing unit5are coupled, the fixing members4d4come into detachable engagement with receiving portions (not shown) of the fixing unit5. In this manner, the base unit4dis fixed to the fixing unit5.

The fixing unit5includes a power supply unit7, a light source device8and a recording unit9. The power supply unit7is provided with a power supply connector7a(FIG. 7) and a power supply cover7b. A power supply cable7cis connected to the power supply connector7a. The power supply unit7is connected to a main power supply section7ethrough a switch7d.

The recording unit9has a front panel9ain which a plurality of insertion slits9bare formed. Recording mediums, such as memory cards, are inserted through the slits9b. The recording unit9has a side plate9cin which a pair of U-shaped guide grooves9dare formed. The guide grooves extend in a substantially horizontal direction. The attachment/ detachment guides4d3of the base unit4dare brought into detachable engagement with the guide grooves9d. The guide grooves9dserve to guide the movement of the base unit4d.

As shown inFIG. 2B, the light source device8comprises an outer cover8a. Although not shown, a lamp box provided with a light source lamp; a relay board; a lamp line board; an EL connector board; an IL switch; a ballast; a fan; etc. are contained in the outer cover8a.

The outer cover8aof the light source device8is provided with a receiving portion (not shown) formed in the surface with which the base unit4dof the scope section4is brought into contact. The light guide connector4d2of the base unit4dis brought into detachable engagement with that receiving portion.

To couple the light source device8of the fixing unit5to the base unit4dof the scope section4, the attachment/detachment guides4d3of the base unit4dof the scope section4are inserted in the guide grooves9dof the recording unit9. In this state, the attachment/detachment guides4d3are slid along the guide grooves9duntil the base unit4dof the scope section4is detachably coupled to the light source device8of the fixing unit5. At the time, the light guide connector4d2of the base unit4dcomes into detachable engagement with the receiving portion (not shown) of the light source device8. In addition, the fixing members4d4of a first connection mechanism10come into engagement with the receiving portion (not shown) of the fixing unit5. In this manner, the light source device8of the fixing unit5and the base unit4dof the scope section4are coupled together.

When the fixing unit5and the base unit4dof the scope section4are coupled together, the main power supply section7eis electrically connected to the electric bending controller52and the camera control unit53through electric contacts. Then, an LCD monitor13cis connected to the camera control unit53through the electric contacts between the base unit4dand the fixing unit5. Therefore, the endoscopic observation images obtained by the CCD of the scope section4are displayed on the LCD monitor13c.

Although not shown, a remote control connector, a BNC connector and a display device13are provided on the upper surface of the outer cover8aof the light source device8. The display device13comprises an LCD monitor13c, for example. This LCD monitor13cis coupled to the top portion of a cylindrical monopod13aby means of a hinge mechanism13b. The hinge mechanism13benables the LCD monitor13cto be opened or closed.

As shown inFIG. 2B, a lamp replacement window14is formed in a side wall of the outer cover8aof the light source device8. A plurality of attachment pins15are projected from that side wall, for attaching the storage section6.

The interior region of the storage section6is divided into a plurality of regions. In the case of the present embodiment, it is divided into the following two: a wide scope storage box6a(i.e., an insertion section storage box); and a narrow remote control storage region6b(i.e., a region in which a cable or the like is stored). In the scope storage box6a, the insertion section4aof the scope section4, the intermediate coupler4band the universal cable4care stored in the bundled state. The storage section6is provided with a storage box cover6c, with which the open section of the scope storage box6ais closed or opened.

A remote control16(an input section) and a flexible cable17are stored in the remote control storage section6b. The base unit4dof the scope section4is operated by use of the remote control16. One end of the cable17is connected to the remote control16. A connector (not shown) is coupled to the other end of the cable17. This connector is detachably connected to the remote control connector of the fixing unit5.

The storage section6has an attachment surface, which is to be attached to the fixing unit5. The attachment surface has pin insertion holes (not shown) at positions corresponding to the attachment pins15of the light source device8. When the attachment pins15of the light source device8are inserted into the pin insertion holes of the storage section6, the storage section6is detachably coupled to the side surface of the outer cover8aof the light source device8.

The storage section6is provided with a scope storage box push member21, which is shaped substantially like “L”. When the storage section6is coupled to the side surface of the outer cover8aof the storage section6, the push member21is fixed to the fixing unit5by means of screws.

The endoscope apparatus1of the present embodiment is provided with two handles23aand23band one shoulder belt24, for placing the assembling case2into the endoscope storage case3or for taking it out of the case3. One (23a) of the handles is provided on the upper surface of the recording unit9of the fixing unit5, while the other handle23bis provided on the upper surface of the outer cover8aof the light source device8. One end of the shoulder belt24is connected to the upper surface of the recording unit of the fixing unit5, while the other end is connected to the upper surface of the outer cover8aof the light source device8. The assembling unit2has a plurality of rubber legs25attached to the bottom.

As shown inFIG. 3, a fixing member40is fixed to one side of the remote control16. The fixing member40enables detachable coupling of the intermediate coupler4b. The fixing member40includes a base plate40a, and two engagement portions40band40cwhich are shaped substantially like “U”. The base plate40ais fixed to one side of the remote control16. The engagement portions40band40care located at the respective ends of the base plate40aand are substantially perpendicular to the lengthwise direction of the base plate40a. When the grip portion4b1of the intermediate coupler4bis inserted between the engagement portions40band40clocated at the respective ends of the fixing member40, the intermediate coupler4bcomes into detachable engagement with one side of the remote control16.

The remote control16includes at least the following: a joystick19; a power button20; and a centering button112(e.g., a centering instruction input means). The joystick19is an instruction input means for remotely bending the bendable portion4a2of the scope section4in the vertical and horizontal directions. The power button20is connected to the switch7dof the power supply unit7.

As shown inFIG. 9A, the joystick19has a proximal end serving as a pivotal support point19, and is pivotally supported. The remote control16includes a variable resistor19cand an A/D conversion section106. The resistance value of the variable resistor19cchanges in accordance with the slanted direction and angle of the joystick19. The A/D conversion section106converts an analog voltage, which is obtained in accordance with the resistance value of the variable resistance19c, into a digital signal.

The A/D conversion section106of the remote control16is electrically connected to the electric bending controller52of the fixing unit5. A bending instruction signal, which is a digital signal obtained at the A/D conversion section106, is supplied to the electric bending controller52.

The electric bending controller52includes a microcomputer107, a D/A converter108, an amplifier109, and an A/D conversion section110used for a potentiometer110. The microcomputer107is electrically connected to the A/D conversion section106of the remote control16and generates a digital driving signal in response to a bending instruction signal supplied from the remote control16. The digital driving signal output from the microcomputer107is supplied to the D/A converter108, by which it is converted into an analog driving signal. The output terminal of the D/A converter108is connected to the motor sections55a2and55b2through the amplifier109. The amplifier109amplifies the analog driving signal obtained by the D/A converter108, and the amplified signal is supplied to the motor sections55a2and55b2.

The microcomputer107includes a CPU, a ROM (which stores a program), a RAM (which can store a program), a differential operation section111, and an A/D conversion section110for potentiometers. The input terminal of the A/D conversion section110is connected to the potentiometers104aand104b, while the output terminal of the A/D conversion section110is connected to the differential operation section110. The A/D conversion section110converts analog resistance values, which represent the rotated positions of the potentiometers104aand104b, into digital signals. An output signal from the A/D conversion section110is supplied to the differential operation section111. The differential operation section111subtracts the bending instruction signal of the A/D conversion section106of the remote control16from the rotation signals the potentiometers104aand104bsense with respect to the sprockets58aand58b. The resultant subtracted signals are used for feedback control.

The microcomputer107includes a centering control section113and a parameter storage section114. The centering button112of the remote control16and the parameter storage section114are connected to the centering control section113. A parameter stored in the parameter storage section114represents how much the bendable portion should operate temporarily in response to an instruction supplied from the centering button112. To be more specific, the parameter represents how much the electric bending controller52should rotate the electric sprockets58aand58b. The rotations of the sprockets are determined based on the rotations of the output shafts55a1and55b1of the potentiometers104aand104b. The signals the microcomputer107actually uses are digital signals obtained by dividing the overall resistance of the potentiometers104aand104bby a predetermined unit value. In response to an instruction supplied from the centering button112, the centering control section113generates a centering instruction by use of a centering parameter stored in the parameter storage section114.

As shown inFIG. 10, the endoscope apparatus1of the present embodiment is provided with a personal computer115in place of the remote control16described above. The personal computer115is detachably attached to the fixing unit5and serves as a return position adjusting means. The personal computer115is connected to the centering control section113of the microcomputer107. The personal computer115changes parameters of the parameter storage section114directly. With the parameters being changed, the degree to which the bendable portion is operated in the direction opposite to that in which it has been bent, can be controlled in accordance with the bending characteristic corresponding to each direction. To be more specific, when the bendable portion is bent in a desired direction by a desired angle and is then returned to the neutral position, the parameter corresponding to a direction in which the bendable portion cannot be easily returned is increased in accordance with the bending characteristic the bendable portion has in that direction.

A description will now be given of the operation of the above configuration. When the endoscope apparatus1of the present invention is carried, the scope section4, the fixing unit5and the storage section6shown inFIG. 2Bare assembled together to form the assembling unit2. This assembling unit2is stored in the endoscope storage case3shown inFIG. 2A. As shown inFIG. 1, the assembling unit2-is stored in the endoscope storage case3and is then covered with the cover3b. In this state, the endoscope apparatus1is carried to a place which is in the vicinity of an object to be inspected.

At the inspection place, the cover3bof the endoscope storage3is opened, as shown inFIG. 1. With the storage box cover6ckept open, the insertion section4aof the scope section4, the intermediate coupler4band the universal cable4care taken out of the scope storage box6a. In addition, the remote control16and the cable17are taken out of the remote control storage region6b. In this state, the insertion section4aof the scope section4is inserted into a space to be inspected, and the space is subject to endoscopic inspection.

In the endoscopic inspection, the bendable portion4a2of the scope section4is operated as described below by use of the joystick19of the remote control16. In the initial state, the bendable portion4a2of the scope section4of the present embodiment is not bent; the bendable portion4a2is held at the neutral position where its entirety is substantially linear (i.e., it is in the non-bent state where the bending angle of the bendable portion4a2is zero). At the time, the joystick19of the remote control16stands upright, and the chains59aand59bof the two pulling force transmission mechanisms57aand57bare neither pulled nor loosened.

To bend the bendable portion4a2upward, the operator moves the joystick19of the remote control16upward. In response to this, an instruction for upward movement is supplied to the A/D conversion section106of the remote control16, for conversion into a digital signal. This digital signal passes through the fixing unit5and is then transmitted to the electric bending controller52.

In the electric bending controller52, the microcomputer107checks the values of the potentiometers104aand104band supplies data on them to the A/D conversion section110. After being converted into digital signals, the values of the potentiometers104aand104bare supplied to the differential operation section111. The differential operation section111calculates the difference components between the rotations of the sprockets58aand58bsensed by the potentiometers104aand104band the bending instruction signals supplied from the A/D conversion section106of the remote control16. Based on this calculation, an instruction is output for bending the bendable portion4a2upward from the linear state is output.

To be more specific, the A/D conversion section106converts the resistance of the variable resistor19cof the joystick19binto a digital signal having a 1024-gradation value in the range from “0” to “1023.” Likewise, the A/D conversion section110converts the resistance values of the potentiometers104aand104binto digital signals having 1024-gradation values in the range from “0” to “1023.”

When the rotational position of the sprocket58afor vertical bending is neutral, the A/D conversion section110outputs median value “512.” Likewise, when the joystick19is at the neutral position, the A/D conversion section106outputs median value “512.” Value “0” corresponds to the maximally upward direction, and value “1023” corresponds to the maximally downward direction. Similarly, the rotational position of the sprocket58bfor horizontal bending and the inclination angle of the joystick19are determined in such a manner that value “0” denotes the maximally leftward direction and value “1023” denotes the maximally rightward direction.

When an instruction for upward bending is input from the joystick19, the A/D conversion section106of the remote control16supplies value “0” to the electric bending controller52. At the time, the value of the A/D conversion section110is “512.” Therefore, the differential operation section111supplies the D/A converter108with an instruction corresponding to a differential amount of (0–512). The instruction is supplied through the amplifier109to the motor section55a2of the motor unit55a. The differential operation section111, the D/A converter108, the amplifier109, the motor section55a2for vertical bending, the potentiometer104aand the A/D conversion section110continue to operate until the value of the A/D conversion section110becomes “0.”

When the operator moves his or her hand off the joystick19, the joystick19returns to the neutral position of itself. At the time, the A/D conversion section106of the remote control16outputs signal “512.” In this case, therefore, the differential operation section111subtracts signal “0” (which is an output of the A/D conversion section110) from signal “512” (which is an output of the A/D conversion section106of the remote control16). Since the subtraction performed then is (512−0), an instruction for moving back to the neutral position is output. When the A/D conversion section110outputs “512”, the motor section55a2is stopped, and the bending operation is thereby stopped.

Even after the sprocket58areturns to the neutral position, the bendable portion4a2may not completely move back to the neutral position. This is because the force corresponding to the position of the sprocket58ais not fully transmitted to the distal end of the bendable portion4a2, due to the frictional resistance between the angle wire101aand the angle coil101b. That is, the bendable portion4a2may be bent slightly upward then. Although the operator has moved the joystick to the neutral position by then, he or she naturally expects that the bendable portion4a2should be at the neutral position, which is not actually the case.

The centering function is utilized for coping with this case. The centering function is enabled by depressing the centering button112of the remote control16. In response to the depression of the centering button112, a centering instruction is supplied to the centering control section113, and a centering operation is executed using a parameter stored in the parameter storage section114. A detailed description will be given as to how this centering operation is executed.

Where the bendable portion4a2is bent upward before the joystick19is returned to the neutral position, the bendable portion4a2may be bent slightly upward even after the joystick19is moved back to the neutral position. In this case, therefore, the centering button112of the remote control16is depressed to provide a centering instruction, based on which the bendable portion4a2is bent downward to a certain degree. If the operation of bending the bendable portion4a2is excessive, the bendable portion4a2will be in the downwardly bent state. In other words, the degree to which the bendable portion4a2is bent downward based on the centering instruction should be appropriate. This bending degree is determined by a parameter.

The operation of bending the bendable portion4a2downward based on the centering operation is started in the state where the bendable portion4a2is bent slightly upward. In this state, the sprocket58ais slightly rotated in the direction corresponding to downward bending, and is then moved to the neutral position. Assuming that the parameter is “30”, the potentiometer104ais moved from the position corresponding to “512” to the position corresponding “512+30”, and is then immediately moved back to the position corresponding to “512.”

The angle wires101a1and101a2are momentarily operated in such a way as to bend the bendable portion4a2downward. In other words, the angle wire101a2for downward bending is pulled, and immediately thereafter the angle wire101a1for upward bending is pulled to move the sprocket58ato the neutral position. By operating the angle wires101a1and101a2in this manner, the bendable portion4a2is momentarily bent downward and is then bent upward. Although the bendable portion4a2is bent downward, it is soon bent upward.

The upward bending operation described above is intended to move the bendable portion4a2from “542” to “512”, and the bendable portion4a2is not operated sufficiently. In addition, the angle at which the bendable portion4a2remains is of a very small value. Moreover, the downward bending operation of the bendable portion4a2is a slight operation in practice by reason of the friction between the angle wire101aand the angle coil101b. Therefore, there may be a case where the bendable portion4a2is only restored to the neutral state from the slightly bent state.

The structural components inside the insertion section4aare not arranged uniformly in the radial direction. As shown inFIG. 8, they are arranged in an eccentric fashion. In the example shown inFIG. 8, the channel tube of the internal channel33, which is soft and has a low restoring force, is located in the lower right region of the cross section of the insertion section4a. It should be noted here that “having a low restoring force” means that the tube cannot be easily restored into its original state after it is bent. Hence, the tube prevents the bendable portion4a2from being restored into the original state even after the joystick19of the remote control16is moved back to the neutral position. In other words, in the example shown inFIG. 8, the bendable portion4a2does not easily return to the neutral position after it is bent rightward or downward, and it returns to the neutral position with comparative ease after it is bent leftward or upward. This is attributable to the difference in the radius of curvature between the case where the bendable portion4a2is bent rightward or downward and the case where it is bent leftward or upward. Where the bendable portion4a2is bent rightward or downward, the radius of curvature of the channel tube of the internal channel33is of a small value, compared to the case where the bendable portion4a2is bent leftward or upward. The bendable portion4a2is hard to return to the neutral position, accordingly.

As can be understood from the above, the parameters corresponding to the four directions must be different. If they are of the same value, the rightward or downward centering does not work satisfactorily.

In the present embodiment, therefore, the personal computer115is connected in the manner shown inFIG. 10, and changes the values of the parameters of the parameter storage section114on the basis of the directions in which the bendable portion4a2can be bent. For example, the parameters corresponding to the directions in which the bendable portion4a2does not easily return are increased, such as “upward 30”, “downward 40”, “rightward 40” and “leftward 30.”

When the bendable portion4a2is bent rightward or leftward, an instruction input at the time of centering is determined in such a manner that the operation of the bendable portion4a2is slightly greater in the leftward or upward direction. Although the instruction signal transmitted to the distal end of the bendable portion4a2may be attenuated to some extent, sufficient centering of the bendable portion4a2is ensured. Hence, the centering operation can be executed with high accuracy without reference to the characteristics of the channel tube of the internal channel33.

The structure described above is advantageous in the following points: The endoscope apparatus1of the present embodiment is provided with the parameter storage section114configured to store variable parameters and the personal computer115configured to change the values of the parameters of the parameter storage section114. The personal computer115is connected in the manner shown inFIG. 10in place of using the remote control16, and the values of the parameters stored in the parameter storage section114are changed directly in accordance with the four directions in which the bendable portion4a2can be bent. With this structure, the bendable portion4a2can return accurately to the neutral position and becomes substantially linear after it is bent in any direction. In this manner, optimal centering is ensured without reference to the bending direction of the bendable portion4a2.

FIG. 11shows the second embodiment of the present invention. The second embodiment differs from the first embodiment (shown inFIGS. 1 through 10) in that the endoscope apparatus1is modified as describe below.

As shown inFIG. 11, the remote control16of the second embodiment is provided with a centering parameter-changing volume121. This volume121serves as a return position adjusting means and controls the degree to which the bendable portion4a2is returned to the neutral position in the direction opposite to that in which it has been bent, in accordance with the bending characteristic corresponding to each direction. The volume121includes a volume121afor upward centering, a volume121bfor downward centering, a volume121cfor rightward centering and a volume121dfor leftward centering.

Like other analog signals, the analog signals output from these volumes121a–121dare converted into digital signals by a centering A/D conversion section122. After this conversion, the signals from the volumes121a–121dare sent to the centering control section113of the microcomputer107by way of the fixing unit5, so that the parameters of the parameter storage section114can be directly changed for control.

In the second embodiment, the volumes121a–121dof the centering parameter-changing volume121of the remote control16are operated to directly change the parameters of the parameter storage section114. As in the first embodiment, when the centering control section113operates, the degree to which the bendable portion4a2is returned to the neutral position can be optimally determined in accordance with the bending characteristic corresponding to each direction. Hence, the bendable portion4a2can return accurately to the neutral position and becomes substantially linear after it is bent in any direction, and optimal centering is ensured at all times.

The second embodiment may be provided with a means for detecting the slanted direction and angle of the joystick19. Where such a detection means is provided, the volumes121a–121dof the centering parameter-changing volume121of the remote control16are automatically changed in accordance with results of detection of the detection means.

The second embodiment may employ a touch panel monitor13cin place of the structure that changes the volumes121ato121dof the centering parameter-changing volume121of the remote control16. Where such a touch panel monitor13cis employed, the values of the parameters of the parameter storage section114can be changed on the software basis by operating the menu displayed on the monitor13c.

FIG. 12throughFIGS. 15A–15Dshow the third embodiment of the present invention. The third embodiment is obtained by modifying the endoscope apparatus1of the first embodiment (shown inFIGS. 1 through 10) as follows:

As shown inFIG. 12, the third embodiment employs a recognition means132for recognizing whether forceps131(FIG. 14) are present in the channel port4b2of the intermediate coupler of the scope section4. The recognition means132includes photo-couplers133aand133b.

In addition, as shown inFIG. 13, the micro-computer107of the electric bending controller52is provided with a bend control means for controlling the bend which the bendable portion4a2should have when it is returned to the neutral position on the basis of the recognition results of the recognition means132. The bend control means includes two parameter storage sections134aand134band a switch135. Each of the two parameter storage sections134aand134bstores centering parameters corresponding to upward, downward, rightward and leftward directions and used for performing a centering operation after the bendable portion4a2is bent in the upward, downward, rightward and leftward directions. However, the centering parameters stored in parameter storage section134adiffer from those stored in parameter storage section134b. For example, parameter storage section134a(referred to as “A” parameter storage section) stores “30”, “40”, “40” and “30” as data corresponding to upward, downward, rightward and leftward directions, respectively, and used for performing a centering operation when the forceps131are not inserted in the internal channel33.

On the other hand, parameter storage section134b(referred to as “B” parameter storage section) stores “10”, “20”, “20” and “10” as data corresponding to upward, downward, rightward and leftward directions, respectively, and used for performing a centering operation when the forceps131are inserted in the internal channel33.

The switch135is located between the centering control section113and the two parameter storage sections134a,134b. The photo-couplers133aand133bare connected to the switch135. On the basis of the recognition results from the photo-couplers133aand133b, the switch135performs switching between the “A” parameter storage section133aand the “B” parameter storage section133b. In this manner, these parameter storage sections are selectively used on the basis of the recognition results of the photo-couplers133aand133b, when a centering operation is performed.

A description will now be given of the operation of the third embodiment described above. When a centering operation is performed after the bendable portion4a2is bent in the upward, downward, rightward or leftward direction, it is necessary to take into account not only the eccentric state of the structural components shown inFIG. 8but also the presence or absence of the forceps131inserted into the internal channel33shown inFIG. 14.

In the case where the forceps131are inserted into the internal channel33in the state shown inFIG. 8, this has to taken into account when the bendable portion4a2is bent in every direction. In other words, the bending operation has to be controlled not only in the rightward and downward directions but also in every direction. Let us consider that the forceps131have a high degree of rigidity. In this case, the rigidity of the forceps enables the joystick19to be easily restored into the neutral state after the bending operation of the forceps131. If the parameters stored in the parameter storage section114and coping with the case where the forceps131are inserted into the internal channel33are applied, the centering operation will be excessively performed.

FIG. 15Ashows how the bendable portion4a2will be when it is bent without inserting the forceps131into the internal channel33and then the joystick19is returned to the neutral position.FIG. 15Billustrates how a centering operation is performed from the state shown inFIG. 15A.

In the case where the joystick19is operated until the bendable portion4a2is bent upward to the position indicated by the imaginary lines inFIG. 15A, and then the joystick19is moved back to the neutral position, the bendable portion4a2will stop in the state where it is slightly bent in the upward direction. The angle the bendable portion4a2forms then is θ1.

If the centering button112of the remote control16is thereafter depressed for a centering operation, the operation for moving the bendable portion4a2back to the neutral position is a combination of the following two bending operations: the downward bending operation of angle φ indicated by arrow X inFIG. 15B; and the upward bending operation indicated by arrow Y1and moving back the bendable portion4a2. That is, the bendable portion4a2is returned to the neutral position in the manner indicated by the solid lines inFIG. 15B.

FIG. 15Cshows how the bendable portion4a2will be when it is bent, with the forceps131inserted into the internal channel33, and then the joystick19is returned to the neutral position.FIG. 15Dillustrates how a centering operation is performed from the state shown inFIG. 15C.

Where the joystick19is operated until the bendable portion4a2is bent upward, and then the joystick19is moved back to the neutral position, the bendable portion4a2is hardly bent by reason of the resiliency of the forceps131, as shown inFIG. 15C. The angle the bendable portion4a2forms then is, for example, θ2 (θ2<θ1). When, in this state, the centering button112of the remote control16is depressed for a centering operation, the downward bending operation of angle φ indicated by arrow X inFIG. 15Dis first performed. It should be noted that the position corresponding to angle X is close to the neutral position in this case. Therefore, although angle φ is the same as that of the case shown inFIG. 15B, angle θ3 is greater than that of the case shown inFIG. 15B. In other words, after the bendable portion4a2is bent downward, it must be moved greatly in the upward direction, as indicated by arrow Y2inFIG. 15D. That means that the bendable portion4a2has to be greatly moved upward from the end position of angle X.

Although the operator merely wants to move the bendable portion4a2shown inFIG. 15Cfrom the position corresponding to θ2 to the neutral position, the centering operation shown inFIG. 15Dmay result in an excessive movement of the bendable portion4a2. That is, the bendable portion4a2moves by angle θ3, as indicated by arrow Y2, and this results in a movement unnecessary for inspection.

The third embodiment therefore employs the photo-couplers133aand133bto detect whether or not the forceps131are inserted in the internal channel33, and switches between the “A” parameter storage section133aand the “B” parameter storage section133bby means of the switch135. Where the forceps131are not present in the internal channel33, the switch135connects the “A” parameter storage section133ato the centering control section113. On the other hand, where the forceps131are present in the internal channel33, the switch135connects the “B” parameter storage section133bto the centering control section113to use parameters of small values.

As described above, in the third embodiment, the photo-couplers133aand133bdetects whether or not the forceps131are present in the internal channel33, and the switch135makes switching between the “A” parameter storage section133aand the “B” parameter storage section133bon the basis of the results of detection. With this feature, the bendable portion4a2can be returned to the neutral position with an appropriate force. After being bent in a desired direction, the bendable portion4a2can be returned to the neutral position where it is substantially linear. Hence, highly precise centering effects are attained.

In the third embodiment, the switch135makes switching between the “A” parameter storage section133aand the “B” parameter storage section133b. In place of this structure, the centering parameter-changing volume121of the second embodiment (FIG. 11) may be used to directly change the values of the parameters of the parameter storage section114.

In addition, the recognition section may be an electrode that is set in an electrically conductive state when the forceps131are inserted. In this case as well, the switch135makes switching between the “A” parameter storage section133aand the “B” parameter storage section133b.

The electrode need not be exposed to the outside; it may be replaced with a non-contact switch that is turned on or off in response to the insertion-of the forceps131.

In connection with the third embodiment, reference was made to the case where the “A” parameter storage section133aand the “B” parameter storage section133bare switched from one to the other. However, the present invention is not limited to this structure. For example, the recognition means may identify a plurality of types of forceps, and parameter storage sections114may be provided in such a manner that they are equal in number to the types the recognition means identifies. In this case, switch135selects one of the parameter storage sections114, and a centering operation is based on the parameters of the selected parameter storage section114.

FIG. 16shows the fourth embodiment of the present invention. The fourth embodiment differs from the first embodiment (FIGS. 1 through 10) in that the endoscope apparatus1is modified as follows:

In the first embodiment, the insertion section4acontains the internal channel33. In the fourth embodiment, the internal channel33is replaced with an external channel141, as shown inFIG. 16. This external channel141is attached to the insertion section4aand bundled together with it by means of a bundling member, such as a tape, an O ring, a binder, or the like. That is, the external channel is used as a side channel of the endoscope.

A pair of clamping members143are provided on one side of the remote control16. The clamping members143can be opened or closed and are capable of clamping the insertion section4aof the scope section4. Each clamping member143has two concave portions on the inner surface thereof. One is a large concave portion143aconfigured to hold the insertion section4aof the scope section4, and the other is a small concave portion143bconfigured to hold the external channel141.

The clamping members143have contacts144aand144b, for the detection of the external channel141. The contacts144aand144bare located near the small concave portions143b. When the contacts144aand144bare electrically connected to each other, it is determined that the clamping members143clamp and hold the external channel141. In response to this determination, the switch135shown inFIG. 13performs switching.

In the fourth embodiment, the contacts144aand144bof the clamping members143are used for determining whether or not the external channel141is used, and the “A” parameter storage section133aand the “B” parameter storage section133bare switched from one to the other on the basis of the determination. Hence, it is possible to appropriately determine how the bendable portion4a2should be bent when it is returned to the neutral position. When the bendable portion4a2is bent in a certain direction and is then returned to the neutral position, the presence of the external channel141does not become a problem. That is, the bendable portion4a2can be reliably returned to the neutral position with high accuracy and becomes substantially linear without reference to the external channel141. Hence, highly precise centering effects are attained.

In place of the contacts144aand144b, the photo-couplers133aand133bshown inFIG. 12may be used for determining whether the external channel141has been attached.

FIG. 17shows the fifth embodiment of the present invention. The fifth embodiment differs from the third embodiment (shown inFIG. 12toFIGS. 15A–15D) in that the endoscope apparatus1is modified as follows:

The fifth embodiment is provided with a current sensing section151for sensing the currents supplied to the motor sections55a2and55b2of the electric bending device51. The current sensing section151is connected to a switch135similar to that employed in the third embodiment. When the current value sensed by the current sensing section151exceeds a predetermined setting value, the switch135switches between the two parameter storage sections134aand134b.

In general, the bending characteristic of the bendable portion4a2is determined by a variety of factors. These factors include not only the eccentric state of the structural components and the presence or absence of forceps but also a winding or looping movement of the insertion section4a. To be more specific, if the insertion section4awinds or loops, the friction between the angle wires101aand the angle coils101bincreases. In accordance with this increase in friction, the force required for angling the angle wire101aalso increases.

If an increase in the force required for angling the angle wire101acan be detected in relation to a change in the bending characteristic, such a force increase can be used for varying the centering parameters. When the bendable portion4a2is bent, power is applied to the motor sections55a2and55b2, and the sprockets58aand58bare rotated for a bending operation. As can be seen from this, the current values supplied to the motor sections55a2and55b2increase when the force required for angling the angle wire101aincreases.

In the fifth embodiment, the current sensing section151senses the current value of the motor sections55a2and55b2of the electric bending device51. When the current value sensed by the current sensing section151exceeds a predetermined setting value, the switch135switches between the two parameter storage sections134aand134b. As a result, it is possible to appropriately determine how the bendable portion4a2should be bent when it is returned to the neutral position, and an optimal centering operation is attained.

The centering parameter-changing volume121shown inFIG. 11may be used in this embodiment. In this case, the centering parameter-changing volume121directly changes the values of the parameters of the parameter storage section114connected to the centering control section113of the microcomputer107, when the current value detected by the current sensing section151has exceeded the predetermined setting value.

The force required for angling angle wires may be detected based on a voltage, not a current. In this case, a voltage sensing section is provided to detect a voltage value applied to the motor sections55a2and55b2. The motor sections55a2and55b2are driven powerfully by increasing the voltage value, so that a high voltage value indicates an increase in the force required for angling angle wires. When the voltage value sensed by the voltage sensing section exceeds a predetermined setting value, the switch135switches between the two parameter storage sections134aand134b.

FIG. 18shows the sixth embodiment of the present invention. The sixth embodiment differs from the first embodiment (FIGS. 1 through 10) in that the endoscope apparatus1is modified as follows:

Like the third embodiment (FIG. 12throughFIGS. 15A–15D), the sixth embodiment employs photo-couplers133aand133bas a recognition means132for recognizing forceps131. The photo-couplers133aand133bare located at the channel port4b2of the intermediate coupler4bof the scope section4.

As shown inFIG. 18, the microcomputer107of the electric bending controller52is provided with an addition section161that adds digital signals on the basis of results of recognition of the recognition means132. When the photo-couplers133aand133bsense forceps131, the addition section161adds digital signals to the signals output from the A/D conversion section106of the remote control16. As a result, an instruction for bending the bendable portion4a2more than the instruction entered from the joystick19is generated, and the generated instruction is supplied to the differential operation section111.

Let us assume that the joystick19is moved upward when the bendable portion4a2is linear. In this case, the A/D conversion section106of the remote control16outputs digital signal “300.” Since the A/D conversion section110outputs “512” then, a normal bending operation corresponds to (300–512). If the photo-couplers133aand133brecognize the forceps131, the addition section161adds a predetermined value α (e.g., “20” in this case).

That is, the bendable portion4a2is bent by (280–512). When the bendable portion4a2is used in combination with the forceps131, it cannot be easily bent. This is compensated for by adding the predetermined value α mentioned above.

The value of α varies depending upon the types of forceps131. Therefore, if the photo-couplers133aand133bare configured to identify a number of types of forceps131, the addition section161can prepare different values as α and add them based on the types identified.

The recognition means132for recognizing the forceps131is not limited to the photo-couplers and may be configured in the manner described in relation to the third embodiment.

In the sixth embodiment as well, not only the internal channel but also the external channel described above is applicable. Where the external channel is provided, the recognition means may be configured to recognize it, or forceps that are inserted into it.

The sixth embodiment may be modified to detect not only the presence/absence of the channel or forceps but also a state of the insertion section4aof the scope section4, as in the fifth embodiment shown inFIG. 17. Where the state of the insertion section is recognized, the addition section161adds digital values in such a manner as to increase the bending angle.

Moreover, the digital signal addition means is not limited to the addition section161described above. It may be an addition section configured to multiply an output of the D/A converter108by a predetermined coefficient, or an addition section configured to enhance the amplification function of the amplifier109.