JP2018102808A - Medical knife - Google Patents

Abstract

It is possible to determine whether a drive signal is good or bad by using a drive signal within one drive cycle. Provide medical scalpel. A liquid ejecting apparatus includes a drive waveform forming unit that outputs a drive signal for driving a piezoelectric element at a predetermined drive cycle, and a waveform inspection unit that inspects the waveform of the drive signal. The waveform inspection unit 31 compares the first determination value 56 and the second determination value 57 smaller than the first determination value 56 with the drive signal indicated by the first signal transition line 54, and the drive signal rises within the drive period 55. The first number that is the number of times that the first determination value 56 is passed and the second number that is the number of times that the drive signal falls and passes the second determination value 57 are counted, and the first number and the second number of times are counted. The drive signal is determined to be normal when both of them are once, and the drive signal is determined to be abnormal when at least one is not one. [Selection] Figure 5

Description

  The present invention relates to a medical knife.

  Medical scalpels using electricity are used for surgery. Examples of the medical knife include an electric knife, an ultrasonic knife, and a water jet knife. The electric scalpel is cut by flowing high-frequency current generated inside from the tip of the scalpel to the human body, causing the contacted tissue to generate heat and explode and evaporate. An ultrasonic scalpel vibrates a metal blade part finely using an ultrasonic vibrator. Thereby, the ultrasonic knife can cut the cell tissue with a light force. A water jet scalpel is cut by applying a high-pressure jet water stream to a cell tissue. At this time, damage to hard cells can be reduced and only soft cells can be cut.

  Patent Literature 1 discloses a medical knife having a pulsating flow generation unit that generates a pulsating flow using a piezoelectric element. In this medical scalpel, the pump forms a water flow, and the pulsating flow generation unit adds a pulsation to the water flow to generate a pulsating flow. And a pulsating flow is injected to a cell tissue. Then, the operator adjusts the frequency, amplitude, pulse width, etc. of the drive signal for driving the piezoelectric element to match the cell tissue to be cut. As a result, the operator can cut only the intended place without damaging the place other than the place to be cut.

JP 2011-038527 A

  An apparatus that operates and electrically controls a drive signal as in Patent Document 1 requires an electric circuit that forms the drive signal. This electric circuit is configured by combining a plurality of electric elements. Each electric element is arranged on the circuit board and connected to the wiring. This electrical element and the joint portion of the contact connecting the electrical element to the wiring deteriorate over time. In addition, the operation of the circuit changes due to dust adhering to the circuit board and moisture contained in the dust. Accordingly, the drive signal may be suddenly deformed as a long time elapses. When the drive signal is deformed, the cutting depth of the cell tissue becomes deeper than expected or the cutting depth becomes shallow. In particular, when cells are cut for medical purposes, it is necessary to prevent such cutting to an unplanned depth. Therefore, there has been a demand for a medical knife that can determine whether a drive signal is good or bad with a drive signal within one drive cycle.

  The present invention has been made to solve the above-described problems, and can be realized as the following forms or application examples.

[Application Example 1]
A medical knife according to this application example, comprising: a drive waveform forming unit that outputs a drive signal that drives a driven element at a predetermined drive cycle; and a waveform inspection unit that inspects the waveform of the drive signal, The waveform inspection unit compares the drive signal with a first determination value and a second determination value smaller than the first determination value, and the drive signal rises and passes the first determination value within the drive cycle. The first number that is the number of times and the second number that is the number of times that the drive signal falls and passes the second determination value are counted, and both the first number and the second number are one. The drive signal is determined to be normal at a certain time, and the drive signal is determined to be abnormal when at least one is not one time.

  According to this application example, the medical knife has the drive waveform forming unit and the waveform inspection unit. The drive waveform forming unit outputs a drive signal for driving the driven element at a predetermined drive cycle. The waveform inspection unit inspects the waveform of the drive signal. When inspecting, the waveform inspection unit compares the first determination value and the second determination value with the drive signal.

  The second determination value is set to a value smaller than the first determination value. The number of times that the drive signal rises and passes the first determination value within the drive cycle is defined as the first number of times. The number of times that the drive signal falls and passes the second determination value is defined as the second number of times. The waveform inspection unit counts the first number and the second number. Then, the waveform inspection unit determines that the drive signal is normal when the first number and the second number in the drive cycle are both one. The waveform inspection unit determines that the drive signal is abnormal when at least one of the first number and the second number in the drive cycle is other than one. Therefore, the waveform inspection unit can determine whether or not the drive signal is good by using the drive signal within one drive cycle.

[Application Example 2]
In the medical knife according to the application example, an inter-passing time that is a time period from when the drive signal rises and passes the first determination value to when the drive signal falls and passes the second determination value. Is shorter than the determination time, the number of times is not added to the first number of times and the second number of times.

  According to this application example, the time from when the drive signal rises and passes the first determination value to when the drive signal falls and passes the second determination value is defined as an inter-passing time. When the time between passages is shorter than the determination time, the driven element does not follow the rise and fall of the drive signal. Noise in which the drive signal changes rapidly is called spike noise. Since the waveform inspection unit does not determine that the drive signal rises and falls as abnormal, it does not add the number to the first number and the second number. As a result, the waveform inspection unit can make a pass / fail determination except for spike noise in which the drive signal changes rapidly.

[Application Example 3]
In the medical knife according to the application example, when the waveform inspection unit determines that the drive signal is abnormal, the drive waveform forming unit stops outputting the drive signal.

  According to this application example, when the waveform inspection unit determines that the drive signal is abnormal, the drive waveform forming unit stops outputting the drive signal. Accordingly, the driving of the driven element is stopped when the waveform inspection unit detects an abnormality in the driving signal in one driving cycle. Therefore, it is possible to suppress the medical scalpel from damaging the affected area.

[Application Example 4]
In the medical scalpel according to the application example, the driving cycle includes a first period and a second period following the first period. The drive signal is determined to be normal when it is one time, and the drive signal is determined to be abnormal when at least one is not one time. When the number of times is both 0, the drive signal is determined to be normal, and when at least one is other than 0, the drive signal is determined to be abnormal, and the waveform inspecting unit detects the first period and the second period. When determining that the drive signal is normal, the drive signal in the drive cycle is determined to be normal.

  According to this application example, the driving cycle is composed of a first period and a second period. The latter period is a period following the first period. The waveform inspection unit determines that the drive signal is normal when the first number and the second number in the previous period are both one. The waveform inspection unit determines that the drive signal is abnormal when at least one of the first number and the second number in the previous period is other than one.

  The waveform inspection unit determines that the drive signal is normal when the first number and the second number in the latter period are both zero. The waveform inspection unit determines that the drive signal is abnormal when at least one of the first number and the second number in the latter period is other than zero. Furthermore, the waveform inspection unit determines that the drive signal in the drive cycle is normal when it determines that the drive signal in the first and second periods is normal. It is determined that the timing at which the drive signal rises and falls to the latter section on the time axis is a sign that the drive waveform forming unit will fail. Therefore, when the drive signal rises and falls in the latter period, it is possible to detect a sign of failure by determining an abnormality.

[Application Example 5]
In the medical knife according to the application example, the driven element is a piezoelectric element that makes a water flow a pulsating flow, and jets the pulsating flow.

  According to this application example, the medical scalpel ejects a pulsating flow. Therefore, the medical knife can cut a soft cell tissue like a brain cell without cutting a hard cell tissue.

FIG. 3 is a schematic perspective view for explaining the configuration of the liquid ejecting apparatus according to the first embodiment. The block diagram which shows the structure of a liquid ejecting apparatus. The schematic cross section which shows the internal structure of a pulsating flow generation part. The graph which shows transition of the volume of a liquid chamber. The graph which shows the waveform of a drive signal. The graph which shows the waveform of a drive signal. The graph which shows the waveform of a drive signal. The graph which shows the waveform of a drive signal. The graph which shows the waveform of a drive signal. The flowchart of the injection method of the pulsating flow using a liquid injection apparatus. The graph which shows the waveform of the drive signal concerning 2nd Embodiment. The graph which shows the waveform of a drive signal.

  Hereinafter, embodiments will be described with reference to the drawings. In addition, each member in each drawing is illustrated with a different scale for each member in order to make the size recognizable on each drawing.

(First embodiment)
In the present embodiment, characteristic examples of a liquid ejecting apparatus and a liquid ejecting method that ejects liquid using the liquid ejecting apparatus will be described with reference to the drawings. The liquid ejecting apparatus according to the first embodiment will be described with reference to FIGS. FIG. 1 is a schematic perspective view for explaining the configuration of the liquid ejecting apparatus. As shown in FIG. 1, a liquid ejecting apparatus 1 as a medical knife is an apparatus that ejects a pulsating liquid onto a soft tissue of a patient to cut the tissue. Hard tissue can be left without cutting. The liquid ejecting apparatus 1 includes a control device 2. The left side of the control device 2 in the figure is the front side, and an operation panel 3 is installed on the front side of the control device 2. Hereinafter, the pulsating liquid is referred to as pulsating flow.

  The right side of the control device 2 in the figure is the back surface of the control device 2, and a pack installation bar 4 is installed on the back surface of the control device 2. A pack 5 in which physiological saline is stored is installed on the pack installation bar 4. A tube 6 is connected to the pack 5, and the tube 6 is connected to a pump 7. Further, the tube 6 extends from the pump 7 and is connected to the handpiece part 8. A nozzle 9 is installed in the handpiece unit 8. The physiological saline contained in the pack 5 is sent to the handpiece part 8 through the tube 6 by the pump 7 and is sprayed from the nozzle 9. Hereinafter, physiological saline is referred to as a liquid. The liquid is a solution of sodium chloride in water. Physiological saline is widely used for surgery because it has no harm to the living body. In this embodiment, the liquid ejected from the nozzle 9 is a pulsating pulsating flow.

  The operation panel 3 is provided with a switch group and a display device for an operator to operate the liquid ejecting apparatus 1. On the lower side of the operation panel 3 in the figure, a main switch 10 for starting the liquid ejecting apparatus 1 is installed. The main switch 10 is a switch that activates the liquid ejecting apparatus 1. The liquid ejecting apparatus 1 is activated by operating the main switch 10.

  In addition, the operation panel 3 is provided with a pulsation amount input switch 11 on the right side in the figure. The pulsation amount input switch 11 is a switch for the operator to input and adjust the flow velocity of the liquid ejected from the nozzle 9 and the fluctuation amount of the pulsation. Hereinafter, the fluctuation amount of the pulsation is referred to as a pulsation amount. The operator operates the pulsation amount input switch 11 to set the pulsation amount. The pulsation amount input switch 11 includes, for example, a push button switch that increases the pulsation amount and a push button switch that decreases the pulsation amount. The number of steps of the pulsation amount set by the operator is not particularly limited, but is set to, for example, 16 steps in this embodiment.

  On the left side of the pulsation amount input switch 11 in the figure, a digital display unit 12 is installed. A numerical value indicating the control state of the liquid ejecting apparatus 1 is displayed on the digital display unit 12. The digital display unit 12 displays various information such as the flow velocity of the liquid to be ejected, the pulsation amount, the operation mode, and the alarm code. The operator operates the liquid ejecting apparatus 1 while confirming the digital display unit 12.

  An operation mode switch 13 is installed on the lower side of the digital display unit 12 in the figure. The operation mode switch 13 is a switch for selecting an operation mode for operating the liquid ejecting apparatus 1. There are multiple modes available, such as a mode that ejects liquid with pulsating flow, a mode that ejects liquid without pulsating flow, and a maintenance mode that eliminates bubbles in the flow path. And the liquid ejecting apparatus 1 can perform a predetermined operation. Further, the operation mode switch 13 can input the period of the drive waveform.

  An optical indicator 14 is installed on the left side of the digital display unit 12 in the drawing. The indicator 14 notifies the state of the liquid ejecting apparatus 1 by blinking or lighting of light. A warning light 15 and a speaker 16 are installed on the left side of the indicator 14 in the drawing. The warning light 15 emits flashing light to attract the operator's attention. The speaker 16 emits a warning sound to attract the operator's attention. The warning lamp 15 and the speaker 16 are parts that warn the operator.

  An injection switch connector 17 is installed below the operation mode switch 13 in the figure. The injection switch connector 17 is connected to the injection switch 21 via the wiring cord 18. The injection switch 21 is a switch that controls the injection and stop of the pulsating flow from the nozzle 9. The injection switch 21 is a stepping switch. The operator operates the injection switch 21 to control the injection of the pulsating flow from the nozzle 9 and the injection stop.

  A handpiece connector 22 is installed on the right side of the injection switch connector 17 in the figure. The handpiece connector 22 is connected to the handpiece portion 8 via the wiring cord 23.

  FIG. 2 is a block diagram illustrating a configuration of the liquid ejecting apparatus. As shown in FIG. 2, the liquid ejecting apparatus 1 includes a hand piece portion 8. The handpiece unit 8 is an instrument that is held and operated by an operator during surgery. The handpiece unit 8 is provided with an ejection pipe 24 that is a liquid flow path. A nozzle 9 that ejects liquid is installed at one end of the ejection pipe 24. A pulsating flow generation unit 25 including a piezoelectric element is installed at the other end of the ejection tube 24. A pump 7 is connected to the pulsating flow generation unit 25 via a tube 6. Further, the pump 7 is connected to the pack 5 via the tube 6. The control device 2 is connected to the pump 7 by the wiring 26 and is connected to the pulsating flow generation unit 25 by the wiring cord 23. The control device 2 controls the operation of the liquid ejecting apparatus 1 via the wiring cord 23 and the wiring 26.

  A liquid 27 is stored inside the pack 5, and the liquid 27 is supplied to the pump 7. The pump 7 is a type of pump that moves the liquid 27 in the tube 6 by handling the tube 6 from the outside by rotating a plurality of rollers by a motor. The pump 7 is also called a tube pump and can continuously flow the liquid 27.

  A main switch 10 is installed in the control device 2. The main switch 10 is a switch that activates the liquid ejecting apparatus 1. When the main switch 10 is turned on, power is supplied to the control device 2. Further, an injection switch 21 is connected to the control device 2 via a wiring cord 18. The injection switch 21 is a foot switch operated with a foot. The ejection switch 21 is a switch for switching between ejection and stop (non-ejection) of the liquid 27 from the nozzle 9.

  When the operator turns on the main switch 10, the control device 2 is activated. After the control device 2 is activated, initial setting processes such as an inspection process before starting use and a liquid filling process are executed. After the initial setting process is completed, when the operator turns on the injection switch 21, the pump 7 is activated and the liquid 27 advances inside the tube 6.

  The liquid 27 traveling through the tube 6 reaches the pulsating flow generation unit 25. The liquid 27 that has reached the pulsating flow generation unit 25 is pulsated by the pulsating flow generation unit 25. The liquid 27 that has passed through the pulsating flow generation unit 25 passes through the ejection pipe 24 and is ejected from the nozzle 9. Since the pulsation is applied to the liquid 27 that has passed through the pulsating flow generation unit 25, the liquid 27 ejected from the nozzle 9 becomes a pulsating flow in which the liquid 27 flows in a pulse shape.

  The operator operates the handpiece unit 8 to bring the nozzle 9 close to the living body. When the operator turns on the ejection switch 21, the liquid 27 ejected from the nozzle 9 collides with the living body. Then, some cell groups of the living body are separated from the living body. When the operator moves the handpiece unit 8, the place where it collides with the living body moves. Then, the operator separates the cell group from the living body and cuts the living body.

  The control device 2 includes an injection control unit 28, a drive waveform forming unit 29, a pump control unit 30, a waveform inspection unit 31, and a warning unit 32. The drive waveform forming unit 29 forms a voltage waveform that drives the pulsating flow generating unit 25. A voltage waveform for driving the pulsating flow generation unit 25 is used as a drive signal. The pulsating flow generation unit 25 is provided with a piezoelectric element, and the piezoelectric element is deformed in response to the drive signal. Therefore, the piezoelectric element is a driven element that is driven by the drive waveform forming unit 29. And the drive waveform formation part 29 outputs the drive signal which drives a piezoelectric element with a predetermined drive period. Due to the deformation of the piezoelectric element, a pressure fluctuation is applied to the liquid 27 passing through the pulsating flow generation unit 25 to form a pulsating flow.

  The pump control unit 30 controls the flow rate of the liquid 27 that the pump 7 flows out. The pump control unit 30 performs control so that the speed at which the pump 7 flows out of the liquid 27 is maintained at a set flow rate. A drive signal output from the drive waveform forming unit 29 to the pulsating flow generation unit 25 is input to the waveform inspection unit 31. And the waveform test | inspection part 31 test | inspects the waveform of a drive signal.

  The waveform inspection unit 31 includes a voltage measurement unit 33, a counting unit 34, and a determination unit 35. The drive signal output from the drive waveform forming unit 29 is input to the voltage measuring unit 33. The voltage measuring unit 33 includes an A / D (Analog / Digital) converter. The voltage measuring unit 33 converts the drive signal from an analog voltage signal to digital data. This digital data is data indicating the waveform of the drive signal. The voltage measuring unit 33 outputs the drive signal that has become the digital data to the counting unit 34.

  The counter 34 compares the drive signal with the first determination value and the second determination value. The second determination value is smaller than the first determination value. The number of times that the drive signal rises and passes the first determination value within the drive cycle is defined as the first number of times. The number of times that the drive signal falls and passes the second determination value within the drive cycle is defined as the second number of times. The counting unit 34 counts the first number and the second number. In this specification, an increase in the voltage value (drive voltage) of the drive signal is expressed as “the drive signal increases” and a decrease in the voltage value of the drive signal is expressed as “the drive signal decreases”. The first determination value and the second determination value are voltage values for comparison with the drive voltage.

  The determination unit 35 compares the first number and the second number with the number determination value to determine whether or not the drive signal is a normal signal. Specifically, this number determination value is set to one time. The drive signal is determined to be normal when both the first number and the second number are one, and the drive signal is determined to be abnormal when at least one of the first number and the second number is other than one. To do.

  The injection control unit 28, the drive waveform forming unit 29, the pump control unit 30, and the waveform inspection unit 31 can perform calculations by a CPU (Central Processing Unit) and a program. In addition, a circuit may be provided for each functional element.

  FIG. 3 is a schematic cross-sectional view showing the internal configuration of the pulsating flow generation unit. The pulsating flow generation unit 25 is provided with an inlet channel 36, a liquid chamber 37, and an outlet channel 38 through which the liquid 27 supplied from the tube 6 passes. The inlet channel 36, the liquid chamber 37, and the outlet channel 38 are formed in the first case 41. The diaphragm 42 is installed so that the liquid chamber 37 is sandwiched between the first case 41 and the diaphragm 42. The tube 6 is connected to the inlet flow path 36, and the injection pipe 24 is connected to the outlet flow path 38.

  On the right side of the first case 41 in the figure, a cylindrical second case 43 is installed in contact with the first case 41. The diaphragm 42 is a disk-shaped thin metal plate, and the outer peripheral portion of the diaphragm 42 is sandwiched and fixed between the first case 41 and the second case 43. On the right side of the second case 43 in the figure, a third case 44 is installed in contact with the second case 43. Between the diaphragm 42 and the third case 44, a piezoelectric element 45 as a driven element, which is a laminated piezoelectric element, is disposed. One end of the piezoelectric element 45 is fixed to the diaphragm 42, and the other end is fixed to the third case 44. The piezoelectric element 45 is connected to the control device 2 by a wiring cord 23, and a drive signal is applied to the piezoelectric element 45 through the wiring cord 23.

  When a drive signal is applied from the drive waveform forming unit 29 of the control device 2, the piezoelectric element 45 changes the volume of the liquid chamber 37 formed between the diaphragm 42 and the first case 41. When the voltage of the drive signal applied to the piezoelectric element 45 increases, the piezoelectric element 45 expands and the diaphragm 42 is pushed by the piezoelectric element 45 and bends toward the liquid chamber 37 side in the first direction 46 in the drawing. When the diaphragm 42 bends in the first direction 46, the volume of the liquid chamber 37 decreases, and the pressure in the liquid chamber 37 increases. Then, the liquid 27 in the liquid chamber 37 is pushed out of the liquid chamber 37. The inner diameter of the outlet channel 38 is larger than the inner diameter of the inlet channel 36. That is, the fluid resistance of the outlet channel 38 is smaller than the fluid resistance of the inlet channel 36. Since the inlet channel 36 is closer to the pump 7 than the outlet channel 38, the water pressure in the inlet channel 36 is higher than the water pressure in the outlet channel 38. Further, the inertance of the outlet channel 38 is smaller than the inertance of the inlet channel 36. Therefore, most of the liquid 27 in the liquid chamber 37 is pushed out of the liquid chamber 37 through the outlet channel 38, passes through the ejection pipe 24, and is ejected from the nozzle 9.

  On the other hand, when the voltage of the drive signal applied to the piezoelectric element 45 decreases, the piezoelectric element 45 contracts, and the diaphragm 42 is pulled by the piezoelectric element 45 and bends toward the third case 44 in the second direction 47 in the figure. . The piezoelectric element 45 is contracted to increase the volume of the liquid chamber 37, the pressure in the liquid chamber 37 is decreased, and the liquid 27 is supplied from the inlet channel 36 into the liquid chamber 37.

  The voltage of the drive signal applied to the piezoelectric element 45 is repeatedly turned on (maximum voltage) and turned off (0 V) at a high frequency of 300 Hz, for example, so that the expansion and reduction of the volume of the liquid chamber 37 are repeated. The pulsation is given to the liquid 27 to be moved. The liquid 27 pushed out from the liquid chamber 37 is ejected from the nozzle 9 at the tip of the ejection tube 24.

  That is, by driving the piezoelectric element 45 at a predetermined frequency, the liquid 27 supplied from the pump 7 can be ejected from the nozzle 9 at the tip of the ejection pipe 24 in the form of a pulsed high-pressure jet flow. The liquid 27 that has become a pulsed high-pressure jet flow ejected from the nozzle 9 excises or crushes a living tissue. In addition, applying a driving signal to the piezoelectric element 45 to expand and contract is expressed as “drive the piezoelectric element 45”.

  Thus, the piezoelectric element 45 as the driven element turns the water flow into a pulsating flow. The liquid ejecting apparatus 1 ejects a pulsating flow. Therefore, the liquid ejecting apparatus 1 can cut a soft cell tissue like a brain cell.

  FIG. 4 is a graph showing the transition of the volume of the liquid chamber. In FIG. 4, the vertical axis indicates the volume of the liquid chamber 37, and the upper side in the figure is smaller than the lower side. The horizontal axis shows the transition of time, and the time transitions from the left side to the right side in the figure. A transition line 48 indicates the transition of the volume when the volume of the liquid chamber 37 is changed.

  The transition line 48 is repeated with a period 49. One cycle 49 is divided into a rising section 50, a descending section 51, and a rest section 52. In the rising section 50, the transition line 48 rises along a substantially straight line. At this time, the voltage applied to the piezoelectric element 45 increases and the piezoelectric element 45 expands. Thereby, the diaphragm 42 is bent in the first direction 46 and the volume of the liquid chamber 37 is reduced. Then, the liquid 27 in the liquid chamber 37 moves to the outlet channel 38.

  In the descending section 51, the volume of the transition line 48 increases gradually along the substantially straight line as compared with the rising section 50. At this time, the voltage applied to the piezoelectric element 45 decreases and the piezoelectric element 45 contracts. Thereby, the diaphragm 42 is bent in the second direction 47 and the volume of the liquid chamber 37 is increased. Then, the liquid 27 flows from the inlet channel 36 into the liquid chamber 37. The descending section 51 is longer than the rising section 50. As a result, the liquid 27 vigorously flows out into the outlet channel 38 and flows into the liquid chamber 37 from the inlet channel 36 at a low speed. The rest section 52 is a section in which the piezoelectric element 45 maintains a contracted state. The period 49 can be adjusted by changing the length of the pause section 52.

  The change amount of the volume in the transition line 48, that is, the difference between the maximum value and the minimum value of the volume in the period 49 is set as the change amount 53. The change amount 53 can be adjusted by the drive waveform forming unit 29 of the control device 2 controlling the output of the drive signal for driving the piezoelectric element 45.

  5 to 9 are graphs showing the waveforms of the drive signals. 5 to 9, the vertical axis indicates the voltage of the drive signal, and the upper side in the figure is higher than the lower side. The horizontal axis shows the transition of time, and the time transitions from the left side to the right side in the figure. A first signal transition line 54 shown in FIG. 5 indicates the waveform of the drive signal output from the drive waveform forming unit 29 to the piezoelectric element 45 of the pulsating flow generating unit 25. The drive waveform forming unit 29 outputs a waveform during the drive cycle 55. When the first signal transition line 54 indicates a signal that repeats in the drive period 55, the drive signal is normal.

  The counting unit 34 compares the drive signal with the first determination value 56 and the second determination value 57. In the first signal transition line 54, the first number of times that the drive signal rises and passes the first determination value 56 within the drive period 55 is one. The second number of times that the drive signal falls and passes the second determination value 57 is one. Since the determination unit 35 determines that the drive signal is normal when both the first number and the second number are one, it determines that the drive signal indicated by the first signal transition line 54 is normal.

  In the second signal transition line 58 shown in FIG. 6, the first number of times that the drive signal rises and passes the first determination value 56 within the drive period 55 is two. The second number of times that the drive signal falls and passes the second determination value 57 is one. Since the determination unit 35 determines that the drive signal is abnormal when at least one of the first number and the second number is other than one, it determines that the drive signal indicated by the second signal transition line 58 is abnormal.

  In the third signal transition line 61 shown in FIG. 7, the first number of times that the drive signal rises and passes the first determination value 56 within the drive period 55 is two. The second number of times that the drive signal falls and passes the second determination value 57 is two. The determination unit 35 determines that the drive signal is abnormal when at least one of the first number and the second number is other than one, and therefore determines that the drive signal indicated by the third signal transition line 61 is abnormal.

  In the fourth signal transition line 62 shown in FIG. 8, the first number of times that the drive signal rises and passes the first determination value 56 within the drive period 55 is two. The second number of times that the drive signal falls and passes the second determination value 57 is one. Since the determination unit 35 determines that the drive signal is abnormal when at least one of the first number and the second number is other than one, it determines that the drive signal indicated by the fourth signal transition line 62 is abnormal.

  The liquid ejecting apparatus 1 includes a drive waveform forming unit 29 and a waveform inspection unit 31. The drive waveform forming unit 29 outputs a drive signal for driving the piezoelectric element 45 at a predetermined drive cycle 55. The waveform inspection unit 31 inspects the waveform of the drive signal. When inspecting, the waveform inspection unit 31 compares the first determination value 56 and the second determination value 57 with the drive signal.

  In this way, the waveform inspection unit 31 counts the first number and the second number. The waveform inspection unit 31 determines that the drive signal is normal when the first number and the second number in the drive cycle 55 are both one. The waveform inspection unit 31 determines that the drive signal is abnormal when at least one of the first number and the second number in the drive cycle 55 is other than one. Therefore, the waveform inspecting unit 31 can determine whether or not the drive signal is good by the drive signal within one drive cycle 55. As a result, when even one of the sequentially output drive signal waveforms becomes abnormal, it can be determined that the waveform of the drive signal is abnormal.

  In the fifth signal transition line 63 shown in FIG. 9, the first number of times that the drive signal rises and passes the first determination value 56 within the drive period 55 is two. The second number of times that the drive signal falls and passes the second determination value 57 is two. However, when the inter-passage time 64, which is the time from when the drive signal increases and passes the first determination value 56 to when the drive signal decreases and passes the second determination value 57, is shorter than the determination time 65, The number of times of the waveform of the drive signal is not added to the first number and the second number. This determination time 65 is a preset value. In FIG. 9, the first inter-pass time 64 a is longer than the determination time 65, but the second inter-pass time 64 b is shorter than the determination time 65. Accordingly, the number of waveforms of the interpassing time 64a is added, but the number of waveforms of the interpassing time 64b is not added, and the first number and the second number are both one, so the determination unit 35 is driven. The signal is determined to be normal. As a result, it is determined that the drive signal indicated by the fifth signal transition line 63 is normal.

  When the passage time 64 is shorter than the determination time 65, the piezoelectric element 45 does not follow the rise and fall of the drive signal. Noise in which the drive signal changes rapidly is called spike noise. Since the waveform inspection unit 31 does not determine that the drive signal rises and falls as abnormal, it does not add the number of times to the first and second times. As a result, the waveform inspection unit 31 can make a pass / fail determination except for spike noise in which the drive signal changes rapidly.

  Next, a pulsating flow ejection method using the above-described liquid ejecting apparatus 1 will be described with reference to FIG. FIG. 10 is a flowchart of the pulsating flow ejection method using the liquid ejecting apparatus. In the flowchart of FIG. 10, step S1 is a drive waveform output start process. In this step, the operator operates the injection switch 21. Next, the injection control unit 28 outputs an instruction signal to start driving the pump 7 to the pump control unit 30. The drive waveform forming unit 29 outputs a drive signal to the pulsating flow generation unit 25. Next, the process proceeds to step S2.

  Step S2 is an initialization process. This step is a step in which the counting unit 34 sets the first number and the second number to zero. Next, the process proceeds to step S3. Step S3 is a rising edge detection step. This step is a step in which the counting unit 34 counts the first number of times. Next, the process proceeds to step S4. Step S4 is a falling detection process. This step is a step in which the counting unit 34 counts the second number of times. Next, the process proceeds to step S5.

  Step S5 is an elapsed time determination step. This process is a process in which the counting unit 34 determines whether or not the time elapsed since the start of step S3 has exceeded the drive cycle 55. When it is within the driving cycle, the process proceeds to step S3. When the elapsed time exceeds the driving cycle 55, the process proceeds to step S6.

  Step S6 is a noise removal step. In this step, it is determined whether or not the passage time 64 is shorter than the determination time 65, and the counting unit 34 calculates the first number and the second number based on the result. Then, when the inter-passage time 64 is shorter than the determination time 65, this is a step of performing a correction to delete (subtract) the number of waveforms of the drive signal from the first number and the second number. There may be a plurality of inter-passing times 64 in the drive cycle 55, and the process of this step is performed for each inter-passing time 64. Next, the process proceeds to step S7.

  Step S7 is a passage number determination step. In this step, the determination unit 35 determines that the drive signal is normal when both the first number and the second number are one. In this step, the determination unit 35 determines that the drive signal is abnormal when the first number or the second number is other than one. When the determination unit 35 determines that the drive signal is normal, the process proceeds to step S8. When the determination unit 35 determines that the drive signal is abnormal, the process proceeds to step S9.

  Step S8 is an end determination step. This step is a step of determining whether or not to finish the ejection of the liquid 27. The operator operates the ejection switch 21 to input an instruction signal for terminating the ejection of the liquid 27 to the control device 2. At this time, it is determined that the ejection control unit 28 ends the ejection of the liquid 27, and then the process proceeds to step S10. When the instruction signal for ending the ejection of the liquid 27 is not input to the control device 2, it is determined that the ejection control unit 28 continues, and then the process proceeds to step S2.

  Step S9 is an abnormality notification step. In this step, the warning unit 32 blinks the warning lamp 15 to notify the operator that the waveform of the drive signal is abnormal. Further, the warning unit 32 makes the speaker 16 emit a warning sound to notify the operator that the waveform of the drive signal is abnormal. Next, the process proceeds to step S10.

  Step S10 is a drive waveform output end process. In this step, the injection control unit 28 outputs an instruction signal for stopping the output of the drive signal to the drive waveform forming unit 29. The drive waveform forming unit 29 receives this instruction signal and stops outputting the drive signal to the pulsating flow generation unit 25. Further, the injection control unit 28 outputs an instruction signal for stopping the driving of the pump 7 to the pump control unit 30. The pump control unit 30 inputs this instruction signal and stops driving the pump 7.

  Thus, when the waveform inspection unit 31 determines that the drive signal is abnormal in step S5, the drive waveform forming unit 29 stops outputting the drive signal. Accordingly, the driving of the pulsating flow generation unit 25 is stopped when the waveform inspection unit 31 detects an abnormality in the drive signal in one drive cycle 55. Therefore, it is possible to suppress the ejection of the pulsating liquid 27 driven by the piezoelectric element 45 with an abnormal drive signal. Accordingly, the liquid ejecting apparatus 1 can be prevented from damaging the affected part. With the above steps, the step of ejecting the pulsating flow using the liquid ejecting apparatus 1 is completed.

As described above, this embodiment has the following effects.
(1) According to the present embodiment, the liquid ejecting apparatus 1 includes the drive waveform forming unit 29 and the waveform inspection unit 31. The drive waveform forming unit 29 outputs a drive signal for driving the pulsating flow generating unit 25 at a predetermined drive cycle 55. The waveform inspection unit 31 inspects the waveform of the drive signal. When inspecting, the waveform inspection unit 31 compares the first determination value 56 and the second determination value 57 with the drive signal.

  The second determination value 57 is set to a value smaller than the first determination value 56. The number of times that the drive signal rises and passes the first determination value 56 within the drive period 55 is defined as the first number of times. The number of times that the drive signal falls and passes the second determination value 57 is defined as the second number of times. The waveform inspection unit 31 counts the first number and the second number. Then, the waveform inspection unit 31 determines that the drive signal is normal when the first number and the second number in the drive cycle 55 are both one. The waveform inspection unit 31 determines that the drive signal is abnormal when at least one of the first number and the second number in the drive cycle 55 is other than one. Therefore, the waveform inspecting unit 31 can determine whether or not the drive signal is good by the drive signal within one drive cycle 55.

  (2) According to this embodiment, the time from when the drive signal rises and passes through the first determination value 56 to when the drive signal falls and passes through the second determination value 57 is defined as the inter-passing time 64. . When the passage time 64 is shorter than the determination time 65, the pulsating flow generation unit 25 does not follow the increase and decrease of the drive signal. Noise in which the drive signal changes abruptly is spike noise. Since the waveform inspecting unit 31 does not determine that the sudden increase and decrease of the drive signal are abnormal, the number of times is not added to the first number and the second number. As a result, the waveform inspection unit 31 can make a pass / fail determination except for spike noise in which the drive signal changes rapidly.

  (3) According to this embodiment, when the waveform inspection unit 31 determines that the drive signal is abnormal, the drive waveform forming unit 29 stops outputting the drive signal. Accordingly, the driving of the pulsating flow generation unit 25 is stopped when the waveform inspection unit 31 detects an abnormality in the drive signal in one drive cycle 55. Accordingly, it is possible to suppress the liquid ejecting apparatus 1 from ejecting liquid due to an abnormal drive signal.

  (4) According to this embodiment, the liquid ejecting apparatus 1 ejects the liquid 27 that has become a pulsating flow. Therefore, the liquid ejecting apparatus 1 can cut a soft cell tissue like a brain cell.

(Second Embodiment)
Next, an embodiment of the liquid ejecting apparatus will be described with reference to the graphs showing the waveforms of the drive signals in FIGS. The difference between the present embodiment and the first embodiment is that the drive cycle 55 is divided into the first period and the latter period to make a pass / fail judgment. Note that description of the same points as in the first embodiment is omitted.

  11 and 12, the vertical axis indicates the voltage of the drive signal, and the upper side in the figure is higher than the lower side. The horizontal axis shows the transition of time, and the time transitions from the left side to the right side in the figure. A sixth signal transition line 68 shown in FIG. 11 indicates the waveform of the drive signal output from the drive waveform forming unit 29 to the pulsating flow generating unit 25. In other words, in the present embodiment, the driving cycle 55 is composed of the first period 69 and the latter period 70 following the first period 69. The counting unit 34 counts the first number and the second number in the previous period 69. Further, the counting unit 34 counts the first number and the second number in the late period 70.

  The determination unit 35 determines that the drive signal is normal when both the first number and the second number in the first period 69 are one, and determines that the drive signal is abnormal when the number is not one. Further, the determination unit 35 determines that the drive signal is normal when both the first number and the second number in the latter period 70 are zero, and determines that the drive signal is abnormal when at least one is not zero. . The waveform inspection unit 31 determines that the drive signal of the drive period 55 is normal when determining that the drive signal of the first period 69 and the second period 70 is normal.

  In the sixth signal transition line 68, the first number and the second number in the previous period 69 are both one. In the sixth signal transition line 68, the first number and the second number in the latter period 70 are both zero. At this time, the determination unit 35 determines that the drive signal indicated by the sixth signal transition line 68 is normal.

  A seventh signal transition line 71 shown in FIG. 12 indicates the waveform of the drive signal output from the drive waveform forming unit 29 to the pulsating flow generating unit 25. In the seventh signal transition line 71, the first number in the first period 69 is one and the second number is zero. In the seventh signal transition line 71, the first number in the latter period 70 is zero and the second number is one. At this time, the determination unit 35 determines that the drive signal indicated by the seventh signal transition line 71 is abnormal.

As described above, this embodiment has the following effects.
(1) According to the present embodiment, the drive cycle 55 is composed of the first period 69 and the latter period 70. The latter period 70 is a period following the first period 69. The waveform inspection unit 31 determines that the drive signal is normal when both the first number and the second number in the first period 69 are one. The waveform inspection unit 31 determines that the drive signal is abnormal when at least one of the first number and the second number in the previous period 69 is other than one.

  The waveform inspection unit 31 determines that the drive signal is normal when both the first number and the second number in the latter period 70 are zero. The waveform inspection unit 31 determines that the drive signal is abnormal when at least one of the first number and the second number in the latter period 70 is other than zero. It is determined that the timing at which the drive signal rises and falls to the later period on the time axis is an indication that the drive waveform forming unit 29 will fail. Therefore, when the drive signal rises and falls in the latter period 70, it is possible to detect a sign of failure by determining that there is an abnormality.

Note that the present embodiment is not limited to the above-described embodiment, and various changes and improvements can be added by those having ordinary knowledge in the art within the technical idea of the present invention. A modification will be described below.
(Modification 1)
In the first embodiment, the rising detection process in step S3 and the falling detection process in step S4 are performed in order. The rising detection process in step S3 and the falling detection process in step S4 may be performed in parallel. Since the number of steps is reduced, inspection can be performed efficiently.

(Modification 2)
In the first embodiment, the noise removal process of step S6 is performed after the elapsed time determination process of step S5. The noise removal process in step S6 may be performed between the falling detection process in step S4 and the elapsed time determination process in step S5. If it is after the falling detection process of step S4, the noise removal process of step S6 can be performed.

(Modification 3)
In the first embodiment, the medical knife is a water jet knife that ejects the pulsating liquid 27 from the handpiece unit 8. In addition, the form of the control device 2 may be applied to a water jet knife that continuously injects liquid or an electric knife that generates heat by cutting a cell tissue by flowing a high-frequency current. In addition, the form of the control device 2 may be applied to an ultrasonic knife that finely vibrates a metal blade using an ultrasonic transducer. Also in these cases, it is possible to determine whether the drive signal is good or bad by using the drive signal within one drive cycle 55 as in the first embodiment.

(Modification 4)
In the first embodiment, the injection control unit 28 stops driving the pulsating flow generation unit 25 and the pump 7 when the waveform inspection unit 31 detects an abnormality in the drive signal. The injection control unit 28 may stop only the pulsating flow generation unit 25 or may stop only the pump 7. In addition, the operator may determine whether or not to stop the ejection of the liquid 27 in response to the notification from the warning lamp 15 and the speaker 16. Since the configuration is simplified, the liquid ejecting apparatus 1 can be easily manufactured.

  DESCRIPTION OF SYMBOLS 1 ... Liquid ejecting apparatus as a medical knife, 25 ... Pulse flow generation part, 29 ... Drive waveform formation part, 31 ... Waveform test | inspection part, 45 ... Piezoelectric element as a driven element, 55 ... Drive period, 56 ... 1st Determination value, 57 ... second determination value, 64 ... time between passages, 65 ... determination time.

Claims (5)

A drive waveform forming section for outputting a drive signal for driving the driven element at a predetermined drive cycle;
A waveform inspection unit for inspecting the waveform of the drive signal,
The waveform inspection unit compares the drive signal with a first determination value and a second determination value smaller than the first determination value,
A first number that is the number of times that the drive signal rises and passes the first determination value within the drive period; and a second number that is the number of times that the drive signal falls and passes the second determination value; Counting,
A medical knife, wherein the drive signal is determined to be normal when the first number and the second number are both one, and the drive signal is determined to be abnormal when the number is not one. The medical scalpel according to claim 1,
After the drive signal rises and passes through the first determination value, the first inter-pass time, which is the time from when the drive signal falls and passes through the second determination value, is shorter than the determination time. A medical knife, wherein the number of times is not added to the number of times and the second number of times. The medical knife according to claim 1 or 2,
The medical scalpel, wherein the drive waveform forming unit stops outputting the drive signal when the waveform inspection unit determines that the drive signal is abnormal. The medical scalpel according to any one of claims 1 to 3,
The driving cycle is composed of a first period and a second period following the first period.
The waveform inspection unit determines that the drive signal is normal when both the first number and the second number in the previous period are one, and abnormally determines the drive signal when at least one is not one And
The waveform inspection unit determines that the drive signal is normal when both the first number and the second number in the latter period are zero, and abnormally determines the drive signal when at least one is not zero. And
The medical scalpel characterized by determining that the drive signal of the drive cycle is normal when the waveform inspection unit determines that the drive signal of the first period and the latter period is normal. The medical scalpel according to any one of claims 1 to 4,
The medical scalpel characterized in that the driven element is a piezoelectric element that pulsates a water flow and jets the pulsating flow.

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