JP2018198854A - Endoscope system - Google Patents

Abstract

To prevent defect by reliably detecting occurrence of abnormality by setting abnormality determination threshold differing between an on state and an off state of an actuator.SOLUTION: An endoscope system includes: an endoscope observing the inside of a subject; an actuator for driving an optical member in the endoscope; an actuator drive circuit supplying current for the actuator and driving the same; a current detection circuit detecting current flowing in a supply line of the current for the actuator; and a control circuit changing threshold of current detection in the current detection circuit between when driving the actuator by the actuator drive circuit and when not driving the same.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an endoscope system suitable for driving a lens provided in an endoscope insertion portion.

  In recent years, endoscopes are used in various fields such as the medical field and the industrial field. For example, endoscopes in the medical field are used for observation of organs in a body cavity, therapeutic treatment using a treatment tool, surgery under endoscopic observation, and the like.

  Some endoscopes include an imaging unit that images a subject. An optical image from the subject is formed on the imaging surface of the imaging element that constitutes the imaging unit via an optical system provided in the insertion unit. The imaging element is configured to obtain an imaging signal by photoelectrically converting an incident optical image. As the optical system, an optical system that can switch optical performance by moving the lens back and forth in the optical axis direction of the optical system may be employed.

  By the way, various actuators are employed in the endoscope. For example, in order to move the lens position between the far end and the near end, an actuator that drives an optical guide to which the lens is attached may be employed.

  In Patent Document 1, a piezoelectric actuator is driven by selecting and driving a piezoelectric actuator in a first driving state and a second driving state that generates a driving force stronger than the driving force in the first driving state. An actuator device with a circuit is disclosed.

  When such an actuator is mounted on an endoscope, an overcurrent (voltage) detection circuit may be provided on the drive line in order to detect a failure of the actuator drive circuit. An upper limit threshold value (abnormality determination threshold value) of the normal drive current is set, and the overcurrent detection circuit determines an abnormality by detecting that a current exceeding the threshold value has flowed. When it is determined in the overcurrent detection circuit that an abnormal current has flowed, for example, by stopping the current supply to the actuator, it is possible to prevent the actuator from failing.

    JP 2005-12999 A

  However, the actuator is not only continuously driven but also intermittently driven, and there is a period in which the actuator is not driven. Even in such an operation stop state of the actuator, a current may flow through the actuator due to a failure of the drive circuit or the like. In this case, when the current is within the abnormality determination threshold value, the overcurrent detection circuit does not determine that there is a failure, and the current continues to flow from the drive circuit to the actuator. This unnecessary current may cause adverse effects such as actuator failure.

  The present invention provides an endoscope system capable of reliably detecting the occurrence of an abnormality and preventing the occurrence of a malfunction by setting different abnormality determination threshold values depending on whether the actuator is on or off. Objective.

  An endoscope system according to the present invention includes an endoscope for observing the inside of a subject, an actuator for driving an optical member in the endoscope, and an actuator driving circuit for supplying current to the actuator for driving. And a current detection circuit for detecting a current flowing in a current supply line to the actuator, and a threshold for current detection in the current detection circuit is changed between when the actuator is driven by the actuator drive circuit and when the actuator is not driven. And a control circuit.

  According to the present invention, by setting different abnormality determination threshold values for the on state and the off state of the actuator, it is possible to reliably detect the occurrence of an abnormality and prevent the occurrence of a malfunction.

1 is a block diagram showing an endoscope system according to a first embodiment of the present invention. 6 is a flowchart for explaining the operation of the embodiment. Explanatory drawing for demonstrating a determination threshold value. 4 is a timing chart for explaining the operation of the embodiment. Explanatory drawing for demonstrating the 2nd Embodiment of this invention. The block diagram for demonstrating a modification. The block diagram for demonstrating a modification.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing an endoscope system according to a first embodiment of the present invention.

  As shown in FIG. 1, an endoscope system 1 includes an endoscope 2 having an image sensor 25, a video processor 3 to which the endoscope 2 is detachably connected and performs predetermined signal processing, and the endoscope 2. Are detachably connected to each other and include a light source device 4 that supplies illumination light to the endoscope 2 and a monitor 5 as a display device that displays an image signal generated by the video processor 3 as an endoscopic image. .

  The endoscope 2 has an elongated insertion portion 6 that is inserted into a body cavity. An operation unit 7 is provided at the rear end of the insertion unit 6, and a universal cord 8 extends from the operation unit 7. The image pickup signal picked up by the image pickup device 25 is transmitted by the universal code 8. A light source connector 11 is provided at the extended end of the universal cord 8, and the light source connector 11 is detachably connected to the light source device 4. In addition, an electric cable 9 is extended to the side of the light source connector 11, and the electric cable 9 is detachably connected to the video processor 3 by an electric connector 12 disposed at the extended end.

  A light guide 13 that transmits illumination light is inserted through the insertion unit 6, the operation unit 7, and the universal cord 8. Then, by connecting the light source connector 11 to the light source device 4, the illumination light from the light source device 4 is transmitted by the light guide 13, and the light guide attached to the illumination window provided at the distal end portion 14 of the insertion portion 6. The transmitted illumination light is emitted from the tip surface 13a.

  The distal end portion 14 is provided with an observation window adjacent to the illumination window, and the observation window is provided with a lens portion 21 for receiving an optical image of a subject such as an illuminated affected area. The lens unit 21 which is an optical member is configured by attaching a lens (not shown) to the lens holding frame 21a. An imaging element 25 is disposed at the rear end of the lens unit 21, and the lens unit 21 forms an object optical image on the imaging surface of the imaging element 25. The lens unit 21 is configured to be movable by an actuator 22 that moves the lens holding frame 21a forward and backward in the optical axis direction.

  For example, the actuator 22 has a cylindrical outer frame (not shown) fixed to the insertion portion 6 of the endoscope 2, and a magnetic force is generated between the endoscope distal end side and the image sensor side of the outer frame. A coil generated by changing the direction may be wound. A lens holding frame 21a is slidably disposed in the outer frame, and a magnet that applies a magnetic force to the lens holding frame 21a is fixed to the distal end side of the endoscope and the imaging element side. According to the actuator 22 having such a configuration, the magnetic force of the magnet and the coil are generated by selectively changing the direction of the magnetic force between the distal end side of the endoscope and the imaging element side according to the direction of the current flowing through the coil. It is possible to selectively move the lens holding frame 21a toward the distal end side of the endoscope or the imaging element side according to the magnetic force to be applied. A current is supplied to the coil through a signal line 26.

  The imaging element 25 is constituted by, for example, a CCD image sensor, and is connected to the video processor 3 via the electrical connector 12 after passing through the insertion portion 6, the universal cord 8, and the cable inserted into the electrical cable 9.

  The video processor 3 includes a control circuit 31 that controls various circuits. The control circuit 31 may be configured by an FPGA (Field Programmable Gate Array), and is configured by a processor using a CPU or the like (not shown) so that each unit can be controlled according to a program stored in the memory. It may be. The video processor 3 includes a power supply circuit 36 that generates a plurality of power supply voltages necessary for the operation of the image sensor 25 and the like. The power supply circuit 36 generates a power supply voltage for each part in the video processor 3. The control circuit 31 can also control the supply of the power supply voltage of the power supply circuit 36 individually for each circuit.

  The video processor 3 includes a signal processing circuit (an image processing unit 32, a preprocessing unit 33, and the like) that performs predetermined signal processing on an imaging signal output from the imaging element 25. The pre-processing unit 33 is controlled by the control circuit 31 and performs predetermined pre-signal processing on the image signal from the image sensor 25. The pre-processing unit 33 is a known signal amplification unit, process circuit, A / D converter, white Consists of a balance circuit and the like. The image processing unit 32 is controlled by the control circuit 31, performs predetermined image processing on the output signal from the preprocessing unit 33, and outputs an image signal for display on the monitor 5. The monitor 5 displays the endoscopic image supplied from the video processor 3 on the display screen.

  The video processor 3 is provided with a CCD drive circuit 34 that drives the imaging device 25 of the endoscope 2. The CCD drive circuit 34 drives the image sensor by supplying drive signals and various synchronization signals to the image sensor 25.

  Further, the video processor 3 is provided with an actuator drive circuit 35 for driving and controlling the actuator 22. The actuator drive circuit 35 can supply power to the actuator 22 via the signal line 26 to drive the lens unit 21 forward and backward.

  In other words, the actuator drive circuit 35 can switch the direction of the drive current to flow through the coil constituting the actuator 22. A focus switch 30 for controlling the focus is disposed on the operation unit 7 of the endoscope 2. The focus switch 30 as the actuator operation unit generates an operation signal for setting the lens unit 21 to the far end position or the near end position based on a user operation. This operation signal is given from the operation unit 7 to the control circuit 31 of the video processor 3 through the electric cable 9. The control circuit 31 generates drive data for driving the actuator 22 based on the operation signal and outputs the drive data to the actuator drive circuit 35.

  The actuator drive circuit 35 drives the lens unit 21 based on the drive data from the control circuit 31. For example, when the far end position is set based on the operation of the focus switch 30 or the like, the actuator drive circuit 35 sends a drive current in the direction in which the magnet on the distal end side of the endoscope is attracted to the coil, and the near end position Is set, the drive current is made to flow in the direction in which the magnet and the coil on the image sensor side are attracted to each other.

  After the lens unit 21 is moved to the far end or the near end by the actuator 22, the lens unit 21 is maintained at the far end or the near end position by the magnetic force of a magnet (not shown). Therefore, the actuator drive circuit 35 does not need to drive the actuator 22 continuously, and only needs to drive the actuator 22 when the lens unit 21 needs to be moved. However, the magnetic force of the magnet is relatively weak, and not only can the lens unit 21 be moved by the magnetic force of the coil, but the lens unit 21 may also be moved by an external impact or the like. Therefore, the actuator driving circuit 35 performs intermittent driving for driving the actuator 22 at a predetermined interval even after the lens unit 21 is moved to the far end or the near end, and the position of the lens unit 21 is set to the far end or the near end. It may be made to maintain.

  In the present embodiment, a current detection circuit 37 is provided on the signal line 26, and the current detection circuit 37 detects a current flowing through the signal line 26 and supplies a detection result to the control circuit 31. Can be done. The control circuit 31 determines whether or not an abnormal current is flowing based on the detection result of the current detection circuit 37. If the control circuit 31 determines that an abnormal current is flowing, the control circuit 31 determines that the actuator drive circuit 35 may be broken, controls the power supply circuit 36, and controls the actuator drive circuit 35. The power supply to is stopped, and the operation of the actuator drive circuit 35 is stopped.

  In the present embodiment, the control circuit 31 changes the determination threshold value used for determining whether or not an abnormal current is flowing between when the actuator 22 is driven and when it is not driven. The term “driving” refers to the case where the actuator driving circuit 35 supplies a current to the actuator 22 to bring the actuator 22 into operation (ON state). This is a case where the current supply to 22 is stopped and the actuator 22 is not operated (off state).

  Further, the control circuit 31 may change the determination threshold according to the drive mode of the actuator 22.

  The control circuit 31 is provided with a memory 38, and the control circuit 31 may store information related to the determination threshold in the memory 38. Note that the control circuit 31 can update the determination threshold value stored in the memory 38 based on a user operation. The control circuit 31 may determine the abnormality by reading out from the memory 38 different determination threshold values when the actuator 22 is driven (on state) and not driven (off state).

  Next, the operation of the embodiment configured as described above will be described with reference to FIGS. FIG. 2 is a flowchart for explaining the operation of the embodiment. FIG. 3 is an explanatory diagram for explaining the determination threshold. FIG. 4 is a timing chart for explaining the operation of the embodiment.

  FIG. 3 is a diagram for explaining the determination threshold value stored in the memory 38. The thick line in FIG. 3 indicates the amplitude of the drive current supplied to the actuator 22, and the drive current is ideally one of a positive predetermined current value, 0, and a negative predetermined current value. . For example, the lens unit 21 can be positioned at the far end by supplying a positive drive current to the actuator 22, and the lens unit 21 can be positioned at the near end by supplying a negative drive current to the actuator 22. . When the drive current is 0, the actuator 22 cannot move the lens unit 21.

  In the drive current, upper and lower threshold values are set for positive and negative currents, respectively. Further, in the present embodiment, even when the actuator 22 is not driven (OFF state), that is, when the driving current should be zero, an upper threshold value different from that when driving (ON state) is set. Yes. In the example of FIG. 3, the upper limit threshold value when not driven is set to a value near zero.

  The video processor 3 is turned on at the rise timing of the power ON from L to H in FIG. The control circuit 31 generates drive data and outputs it to the actuator drive circuit 35. In step S1, the actuator drive circuit 35 generates and outputs a drive current based on the drive data. This drive current is supplied to the actuator 22 via the signal line 26. Thereby, the actuator 22 is driven to position the lens unit 21 at the far end or the near end.

  The control circuit 31 reads an upper limit threshold and a lower limit threshold (hereinafter referred to as a first determination threshold) when the actuator 22 is driven from the memory 38 (step S2). The drive current supplied to the actuator 22 is detected by the current detection circuit 37, and the detection result is supplied to the control circuit 31 (step S3). Based on the first determination threshold and the detection result of the drive current, the control circuit 31 determines whether the drive current is a value between the lower limit threshold and the upper limit threshold (step S4). When the actuator drive circuit 35, the actuator 22, the signal line 26, etc. are normal, the drive current is considered to be a value between the lower limit threshold and the upper limit threshold. When the drive current is a value between the lower limit threshold value and the upper limit threshold value, the control circuit 31 determines that the drive circuit is operating normally, and proceeds to step S5.

  In step S5, the control circuit 31 stops the driving of the actuator 22 for intermittent driving. That is, the control circuit 31 generates drive data for setting the drive current to 0 and outputs it to the actuator drive circuit 35. As a result, the actuator drive circuit 35 sets the drive current to 0 and stops the drive of the actuator 22.

  In the present embodiment, when driving of the actuator 22 is stopped, the control circuit 31 reads from the memory 38 an upper limit threshold value (hereinafter referred to as a second determination threshold value) when the actuator 22 is not driven (step S6). The drive current to the actuator 22 is detected by the current detection circuit 37 (step S7), and the control circuit 31 determines that the drive current is lower than the upper limit threshold based on the second determination threshold and the detection result of the drive current. It is determined whether or not (step S7).

  Even when the actuator 22 is not driven, if the actuator drive circuit 35, the actuator 22, the signal line 26, etc. are normal, the drive current is considered to be a value lower than the upper limit threshold. If the drive current is smaller than the upper limit threshold, the control circuit 31 determines that the drive circuit is operating normally, and the process proceeds to step S9.

  In step S9, the control circuit 31 determines whether or not the focus switch 30 has been operated. If not operated (L of the focus switch in FIG. 4), the control circuit 31 enters a standby state in step S11 to determine whether or not the intermittent drive stop period has elapsed. Is returned to step S1, and the generation of the drive current is resumed.

  As shown in the drive current of FIG. 4, the actuator 22 is intermittently driven by, for example, a positive drive current to maintain the far end position, for example, and is intermittently driven by, for example, a negative drive current, for example, the near end position. To maintain.

  If the control circuit 31 determines in step S9 that the focus switch 30 has been operated (the focus switch H in FIG. 4), the drive data for reversing the direction of the drive current in step S10. And output to the actuator drive circuit 35. As a result, in step S1, the actuator drive circuit 35 generates a drive current in the direction opposite to the previous time and supplies the drive current to the actuator 22 (from positive to negative drive current in FIG. 4). Thereby, the actuator 22 urges the lens unit 21 in the direction opposite to the previous time. Thus, the lens unit 21 located at the far end moves to the near end. Note that when the drive current is reversed, the lens unit 21 located at the near end moves to the far end.

  Here, when the actuator 22 is driven, some abnormality occurs and the drive current exceeds the upper limit threshold. In this case, if the control circuit 31 determines in step S4 that the drive current has exceeded the upper limit threshold value, the control circuit 31 shifts the process to step S12 to stop the power supply from the power supply circuit 36 to the actuator drive circuit 35. Thus, the supply of drive current by the actuator drive circuit 35 is stopped. Thereby, it is possible to prevent the actuator 22 and the like from being damaged due to overcurrent.

  Further, it is assumed that some abnormality occurs and the drive current flows when the actuator 22 is not driven. No current flows when the actuator is not driven. Therefore, it is considered that an abnormality has occurred even when a current of the same level as that during driving flows. However, an abnormality cannot be detected with the same determination threshold level as that during driving. In the present embodiment, the upper limit threshold value when the actuator 22 is not driven is set to a value close to 0. Even when a relatively small current flows, the control circuit 31 determines that the current is the upper limit threshold value in step S8. Can be determined. When the control circuit 31 determines that the current has exceeded the upper limit threshold, the process proceeds to step S12, the power supply from the power supply circuit 36 to the actuator drive circuit 35 is stopped, and the drive current generated by the actuator drive circuit 35 is stopped. Stop supplying. As a result, no current flows through the actuator 22 or the like for a long time, and it is possible to prevent an adverse effect such as a failure from occurring.

  As described above, in the present embodiment, in an endoscope equipped with an actuator, different judgment thresholds are set when the actuator is driven and when it is not driven. Judgment is possible. Thereby, it is possible to reliably detect the occurrence of an abnormality and prevent the occurrence of a malfunction.

(Second Embodiment)
FIG. 5 is an explanatory diagram for explaining a second embodiment of the present invention. The hardware configuration of this embodiment is the same as that of the first embodiment. The present embodiment shows an example in which the determination threshold is not only switched between when the actuator is driven and when it is not driven, but is also changed according to the operation mode during driving.

  In the description of FIG. 2 of the first embodiment, the actuator drive circuit 35 drives the actuator 22 every time the predetermined period of step S11 elapses even after the lens unit 21 is moved to the far end or the near end. An example in which intermittent driving is performed to maintain the position of the lens unit 21 at the far end or the near end has been described. In the present embodiment, the operation mode of the actuator 22 for moving the lens unit 21 to the far end or the near end is set as the first drive mode, and thereafter the lens unit 21 is maintained at the far end or the near end. The operation mode of the actuator 22 is a second drive mode.

  In the first drive mode and the second drive mode, only the value of the drive current is different. In the second drive mode, it is not necessary to move the lens unit 21, and therefore the second drive mode is the second drive mode compared to the first drive mode. In this driving mode, the current value is lowered. In this case, in the present embodiment, the determination threshold value is changed according to the drive current, and the determination threshold value in the second drive mode (upper limit and lower limit threshold values) than the determination threshold value in the first drive mode (upper limit and lower limit threshold values). The value is smaller than the upper and lower thresholds). Note that the determination threshold value when the actuator 22 is not driven is set to a value different from the determination threshold value when driving, for example, a value near 0, as in the first embodiment.

  FIG. 5 shows an example in the case of having the first to third drive modes. The ideal drive current in the first drive mode is IM1, and the ideal drive current in the second drive mode is IM2. The ideal drive current in the third drive mode is IM3. In the first drive mode, an upper limit threshold Th1 and a lower limit threshold Tl1 are set corresponding to the drive current IM1. Similarly, in the second drive mode, an upper limit threshold Th2 and a lower limit threshold Tl2 are set corresponding to the drive current IM2, and in the third drive mode, an upper limit threshold Th3 and a lower limit threshold Tl3 are set corresponding to the drive current IM3. Is set.

  Although only the positive drive current is shown in FIG. 5, the determination threshold is set for each mode for the negative drive current as in FIGS.

  The embodiment configured as described above is different from the first embodiment only in that a current abnormality is detected in each drive mode using a determination threshold corresponding to each drive mode. Also in the present embodiment, when the actuator 22 is not driven, a determination threshold different from that at the time of driving, that is, an upper threshold near 0 is set, and a relatively small current flows when a current that should not flow originally flows. Even so, it can be determined as abnormal.

  As described above, also in this embodiment, the same effect as that of the first embodiment can be obtained. Furthermore, in the present embodiment, a determination threshold value can be set according to the operation mode, so that more reliable abnormality detection is possible in each operation mode.

(Modification)
6 and 7 are block diagrams for explaining a modification. This modification shows an example in which the arrangement positions of the control circuit, the actuator drive circuit, the power supply circuit, and the current detection circuit are different. FIG. 6 corresponds to the first or second embodiment, and shows that the control circuit 31 a, the actuator drive circuit 35 a, the power supply circuit 36 a, and the current detection circuit 37 a are in the video processor 3.

  In FIG. 6, a control circuit 31a, an actuator drive circuit 35a, a power supply circuit 36a, and a current detection circuit 37a correspond to the control circuit 31, the actuator drive circuit 35, the power supply circuit 36, and the current detection circuit 37 of FIG. The actuator is operated in the same manner with the same function as each circuit in FIG.

  7 shows that the control circuit 31b, actuator drive circuit 35b, power supply circuit 36b, and current detection circuit 37b having the same configuration as the control circuit 31a, actuator drive circuit 35a, power supply circuit 36a, and current detection circuit 37a are provided in the operation unit 7. An example is shown in FIG.

  Other configurations and operations are the same as those in the first or second embodiment.

  6 and 7 show an example in which the control circuit, the actuator drive circuit, the power supply circuit, and the current detection circuit are arranged in the video processor 3 or the operation unit 7, but are arranged in the electrical connector 12. Alternatively, the video processor 3, the electrical connector 12, and the operation unit 7 may be arranged in a distributed manner.

  The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, you may delete some components of all the components shown by embodiment.

  Of the techniques described here, the control mainly described in the flowchart is often settable by a program and may be stored in a semiconductor or other recording medium or recording unit. The recording method for the recording medium and the recording unit may be recorded at the time of product shipment, may be a distributed recording medium, or may be downloaded via the Internet.

    DESCRIPTION OF SYMBOLS 1 ... Endoscopy system, 2 ... Endoscope, 3 ... Video processor, 4 ... Light source device, 6 ... Insertion part, 21 ... Lens part, 22 ... Actuator, 25 ... Image sensor, 26 ... Signal line, 31 ... Control Circuit 34... CCD drive circuit 35. Actuator drive circuit 36. Power supply circuit 37 37 Current detection circuit 38 Memory

Claims (6)

An endoscope for observing the inside of the subject;
An actuator for driving an optical member in the endoscope;
An actuator driving circuit for supplying current to the actuator and driving the actuator;
A current detection circuit for detecting a current flowing in a current supply line to the actuator;
An endoscope system comprising: a control circuit that changes a current detection threshold value in the current detection circuit depending on whether the actuator is driven or not by the actuator drive circuit.   The endoscope system according to claim 1, wherein the control circuit changes a current detection threshold in the current detection circuit for each operation mode during the driving.   The control circuit has a lower threshold value in the second operation mode for maintaining the position of the optical member moved in the first operation mode than the threshold value in the first operation mode for moving the optical member. The endoscope system according to claim 2, wherein:   The endoscope according to claim 1, wherein the control circuit sets an upper limit value and a lower limit value as the threshold values during the driving, and sets an upper limit value as the threshold values during the non-driving. Mirror system.   The endoscope system according to claim 1, wherein the actuator driving circuit, the current detection circuit, and the control circuit are provided in a video processor that processes an endoscope image from the endoscope.   The endoscope system according to claim 1, wherein the actuator drive circuit, the current detection circuit, and the control circuit are provided in the endoscope.

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