Patent Publication Number: US-2021178065-A1

Title: Medical apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a bypass continuation of PCT Application No. PCT/JP2019/021540, filed on May 30, 2019, which claims priority to Japanese Application No. 2018-158757, filed on Aug. 27, 2018. The contents of these applications are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a medical apparatus and, in particular, to a medical apparatus that receives input operation by an operator. 
     BACKGROUND 
     There is known a medical apparatus that includes an input device that receives input operation by an operator, sets a setting value on the basis of the received input operation, and operates on the basis of the set setting value. Examples of such a medical apparatus include a syringe pump in which a syringe containing liquid, such as liquid medicine, is placed, the syringe pump being configured to deliver the liquid into a living body of a patient, or the like, while controlling a flow rate by controlling pushing speed of a pusher of the placed syringe, according to a setting value set by an operator. In a medical apparatus such as a syringe pump, for example, a rotary member such as a dial may be used as an input device used to set a predetermined setting value for an administration rate, or the like, and the setting value can be increased or decreased according to a rotation amount of the rotary member (e.g., refer to JP 2004-24884 A). 
     SUMMARY 
     In a medical apparatus using a rotary member as an input device, a gap is likely to be formed between the rotary member and a member, such as a housing, provided with the rotary member. There has been a possibility that the rotary member is difficult to rotate, and that operability is reduced, by liquid such as highly viscous liquid medicine or another foreign substance entering into such a gap. 
     An object of the present disclosure is to provide a medical apparatus capable of limiting reduction in operability even if a foreign substance such as liquid adheres. 
     A medical apparatus as a first aspect of the present invention includes an operation reception unit, a position acquisition unit that can acquire position information of a detection target based on a position of the detection target on the operation reception unit at an acquisition time that occurs in a predetermined cycle, the detection target being in contact with or proximate to the operation reception unit, and a control unit that determines an operation position of the detection target on the operation reception unit at a last acquisition time before a latest acquisition time, on the basis of the position information acquired at the latest acquisition time. 
     In the medical apparatus as an embodiment of the present invention, the control unit determines, on the basis of position information acquired at the latest acquisition time and at a last acquisition time before the latest acquisition time, the operation position at the last acquisition time before. 
     In the medical apparatus as an embodiment of the present invention, in a case in which the position information is not acquired at at least one of the latest acquisition time or at the last acquisition time before, the control unit determines that the detection target is not in the operation position on the operation reception unit at the last acquisition time before. 
     In the medical apparatus as an embodiment of the present invention, in a case in which an operation mode is in a predetermined operation mode, and position information acquired at the latest acquisition time and position information acquired at the last acquisition time before match, the control unit determines a position indicated by the matched position information as the operation position. 
     In the medical apparatus as an embodiment of the present invention, in a case in which an operation mode is in a predetermined operation mode, and position information acquired at the latest acquisition time and position information acquired at the last acquisition time before do not match, the control unit determines an operation position at a second to last acquisition time before the latest acquisition time as the operation position. 
     In the medical apparatus as an embodiment of the present invention, the predetermined operation mode is a mode that detects low-speed input by the detection target. 
     In the medical apparatus as an embodiment of the present invention, in a case in which the detection target is moving in a state of being in contact with or proximate to the operation reception unit at a speed of a predetermined threshold or lower, the control unit operates in a mode that detects the low-speed input. 
     In the medical apparatus as an embodiment of the present invention, in a case in which an operation mode is not in the predetermined operation mode, the control unit determines a position indicated by position information acquired at a last acquisition time before the latest acquisition time as the operation position. 
     In the medical apparatus as an embodiment of the present invention, the control unit increases or decreases a predetermined setting value on the basis of a change in the determined operation position in a circumferential direction around a predetermined center point on the operation reception unit. 
     In the medical apparatus as an embodiment of the present invention, the position acquisition unit has a plurality of detection regions arranged along the circumferential direction, and acquires any one of the plurality of detection regions as the position information. 
     According to the medical apparatus of the present disclosure, it is possible to limit reduction in operability even if a foreign substance such as liquid adheres. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a perspective view of a syringe pump as a medical apparatus according to an embodiment of the present invention. 
         FIG. 2  illustrates a block diagram of a configuration of the syringe pump illustrated in  FIG. 1 . 
         FIG. 3  illustrates a diagram of detection regions of a position acquisition unit included in the syringe pump illustrated in  FIG. 1 . 
         FIG. 4  is a flowchart that illustrates operation position determination processing performed by the syringe pump illustrated in  FIG. 1 . 
         FIG. 5  illustrates a diagram for describing an example of a method for determining an operation position by the syringe pump illustrated in  FIG. 1 . 
         FIG. 6  illustrates a diagram for describing an example of a method for determining an operation position by the syringe pump illustrated in  FIG. 1 . 
         FIG. 7  illustrates a diagram for describing an example of a method for determining an operation position by the syringe pump illustrated in  FIG. 1 . 
         FIG. 8  illustrates a diagram for describing an example of a method for determining an operation position by the syringe pump illustrated in  FIG. 1 . 
         FIG. 9  illustrates a schematic diagram of an example of a state in which a finger as a detection target is released from an operation reception unit. 
         FIG. 10  is a flowchart that illustrates setting value increase/decrease processing performed by the syringe pump illustrated in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     An embodiment of the present invention will be described below with reference to the drawings. In each figure, common components are denoted by the same reference signs. 
     [Configuration of Syringe Pump] 
       FIG. 1  illustrates a perspective view of a syringe pump  1  as a medical apparatus according to an embodiment of the present invention.  FIG. 1  illustrates the syringe pump  1  on which a syringe  50  is placed. As illustrated in  FIG. 1 , the syringe pump  1  is configured as a pump that delivers liquid contained in a hollow part  52  of the syringe  50 .  FIG. 2  illustrates a block diagram of a configuration of the syringe pump  1 . 
     As illustrated in  FIGS. 1 and 2 , the syringe pump  1  includes a placement unit  11 , a slider  12 , a clamp  14 , a cylinder flange retainer  15 , a circuit unit  20 , an input button group  31 , a display unit  32 , a slider drive unit  36 , an operation reception unit  40 , a housing  46 , and a position acquisition unit  60 . 
     As illustrated in  FIG. 1 , the syringe  50  can be placed on the placement unit  11 . The syringe  50  placed on the placement unit  11  has a cylinder  51  that has a cylindrical shape and defines the hollow part  52  inside, and a pusher  55  that is inserted from a base end side of the cylinder  51  into the hollow part  52  and is movable, in the hollow part  52 , along an extending direction A of the cylinder  51  (hereinafter simply described as “extending direction A”), while adhering without a gap to an inner circumferential surface of the cylinder  51  in a circumferential direction. The cylinder  51  has a cylinder flange  53  at a base end part, and defines, at a tip end part, an outlet hole  54  that communicates the hollow part  52  with an outside. A flexible tube can be connected to the tip end part of the cylinder  51 . When the tube is connected to the tip end part of the cylinder  51 , the outlet hole  54  communicates with a fluid path defined by the tube. Liquid such as liquid medicine is contained in the hollow part  52  of the syringe  50 . Hereinafter, of the extending direction A, a tip end side of the cylinder  51  is described as a “tip end side of the extending direction A”, and the base end side of the cylinder  51  is described as a “base end side of the extending direction A”. 
     As illustrated in  FIG. 1 , the cylinder  51  of the syringe  50  can be placed on the placement unit  11 . Furthermore, as illustrated in  FIG. 1 , when the cylinder  51  of the syringe  50  is placed on the placement unit  11 , the cylinder flange retainer  15  stores a portion of the cylinder flange  53 . With this arrangement, the position of the cylinder  51  with respect to the syringe pump  1  is fixed. 
     As illustrated in  FIG. 1 , the slider  12  has a pusher fixing unit  13 . The slider  12  is movable so as to engage with the pusher  55  of the syringe  50  placed on the placement unit  11 . Specifically, at a position to the base end side of the extending direction A from the pusher  55  of the syringe  50  placed on the placement unit  11 , the slider  12  is movable along the extending direction A. With the pusher fixing unit  13 , the slider  12  fixes the pusher  55  of the syringe  50  placed on the placement unit  11 . In a state where the pusher  55  is fixed to the slider  12  by the pusher fixing unit  13 , the pusher  55  moves integrally with the slider  12  as the slider  12  moves along the extending direction A. At this time, the cylinder  51  placed on the placement unit  11  is fixed to the syringe pump  1  by the cylinder flange retainer  15  in the extending direction A. Therefore, when the slider  12  moves to the tip end side of the syringe  50 , the pusher  55  moves to the tip end side with respect to the cylinder  51 , and the liquid contained in the hollow part  52  is discharged from the outlet hole  54 . For this reason, the liquid contained in the hollow part  52  can be delivered toward a living body through the fluid path defined by the tube connectable to the tip end part of the cylinder  51 . 
     As illustrated in  FIG. 1 , the clamp  14  is movable along a direction B orthogonal to the extending direction A and can fix the cylinder  51  of the placed syringe  50  so that the cylinder  51  is sandwiched between the clamp  14  and the placement unit  11 . Furthermore, the cylinder  51  is fixed to the syringe pump  1  firmly, because fixing the cylinder  51  with the clamp  14  makes a portion of the cylinder flange  53  difficult to come off the cylinder flange retainer  15 . 
     As illustrated in  FIG. 2 , the circuit unit  20  includes a communication unit  21 , a clocking unit  22 , a storage unit  23 , and a control unit  24 . 
     The communication unit  21  includes an interface that transmits or receives information to or from an external information processing device, such as a computer, by wireless communication or wire communication. 
     The clocking unit  22  measures time and keeps time. The clocking unit  22  may be implemented by, for example, a real time clock (RTC). The clocking unit  22  may be implemented as one function of the control unit  24 . 
     The storage unit  23  is configured to include, for example, a storage device and stores various pieces of information and programs. Specifically, the storage unit  23  stores a program for performing setting value increase/decrease processing, various pieces of input support processing, or the like, which is performed by the control unit  24 . Furthermore, the storage unit  23  stores information about a predetermined setting value for a flow rate, a dosage, or the like of liquid delivered by the syringe pump  1 , a control program for delivering the liquid by driving the slider drive unit  36  on the basis of the predetermined setting value, or the like. Furthermore, the storage unit  23  stores the position information acquired by the position acquisition unit  60 . Details of position information that the storage unit  23  stores will be described below. 
     The control unit  24  includes a processor that implements a predetermined function by reading a predetermined piece of information and program, for example, from among the various pieces of information and programs stored in the storage unit  23 , and the control unit  24  controls overall operation of the syringe pump  1 . As will be described below, the control unit  24  identifies operation input from the operation reception unit  40  by a detection target, such as a fingertip of an operator. Specifically, the control unit  24  reads the predetermined piece of information and program stored in the storage unit  23 , and performs operation position determination processing, setting value increase/decrease processing, various pieces of input support processing, or the like. Details of the operation position determination processing and the setting value increase/decrease processing will be described below. The control unit  24  transmits or receives information to or from an external information processing device via the communication unit  21 . The control unit  24  performs various pieces of processing on the basis of information input from the input button group  31  and the position acquisition unit  60 , and outputs, from the display unit  32 , information associated with the performing of the various pieces of processing. 
     As illustrated in  FIG. 1 , the input button group  31  is arranged on a surface of the housing  46  and includes various operation buttons configured to receive an input operation by the operator. The input button group  31  includes, for example, a power button for switching on and off operation power supply of the syringe pump  1 , a start button for starting liquid delivery, and a stop button for stopping liquid delivery. The input button group  31  outputs input information to the control unit  24 . 
     As illustrated in  FIG. 1 , the display unit  32  includes, for example, a display device such as a liquid crystal display, an organic EL display, or the like. On the basis of a signal from the control unit  24 , the display unit  32  displays a setting value or measured value of a flow rate of liquid to be delivered, a setting value or measured value of a dosage of liquid to be delivered, various pieces of alarm information, or the like. 
     The slider drive unit  36  includes, for example, a motor, and moves the slider  12  along the extending direction A (refer to  FIG. 1 ) on the basis of a signal from the control unit  24 . 
     As illustrated in  FIG. 1 , the operation reception unit  40  is arranged so that at least a portion of the operation reception unit  40  is exposed to an outside of the syringe pump  1 . Details of the operation reception unit  40  will be described below. 
     The position acquisition unit  60  can acquire position information based on a position, with respect to the operation reception unit  40 , of the detection target, such as the fingertip of the operator, in contact with or proximate to the operation reception unit  40 . The position acquisition unit  60  acquires position information at a predetermined acquisition time. The predetermined acquisition time occurs, for example, in a predetermined cycle. The predetermined acquisition time occurs, for example, every 10 milliseconds. In this case, the position acquisition unit  60  acquires position information every 10 milliseconds. However, the predetermined cycle is not limited to 10 milliseconds. The predetermined cycle may be determined as appropriate according to an application, a specification, or the like of the operation reception unit  40 . The position acquisition unit  60  outputs the acquired position information to the control unit  24 . 
     The position acquisition unit  60  is an electric field type position detection sensor that can acquire position information of the detection target by, for example, generating an electric field around the operation reception unit  40  and detecting disturbance of the electric field generated by the detection target coming proximate to the operation reception unit  40 . Alternatively, the position acquisition unit  60  can be a capacitance type position detection sensor that can acquire position information of the detection target by, for example, detecting a change in capacitance generated by the detection target coming into contact with a surface of the operation reception unit  40 . In a case in which the position acquisition unit  60  is the above-described electric field type position detection sensor, the position information of the detection target can be acquired even in a case in which, for example, the operator wears rubber gloves or the like, and a finger of the operator does not directly touch the operation reception unit  40 . 
       FIG. 3  is a diagram illustrating an arrangement of the detection regions as position information that can be acquired by the position acquisition unit  60 . As illustrated in  FIG. 3 , the position acquisition unit  60  of the present embodiment has a plurality of detection regions arranged without a gap around a predetermined center point  41  on the operation reception unit  40 , along circumferential directions C, which are, for example, eight fan-shaped detection regions  61   a  to  61   h . Hereinafter, the eight detection regions  61   a  to  61   h  are also referred to as an area a to an area h, respectively. 
     The position acquisition unit  60  acquires, as position information of the detection target, a detection region closest to the detection target from among the plurality of detection regions  61   a  to  61   h . Specifically, in a case in which the position acquisition unit  60  includes, for example, an electric field type position detection sensor, the position acquisition unit  60  acquires information indicating a position of the detection target in a three-dimensional space, and acquires, as position information of the detection target, a detection region closest to the position. In a case in which, for example, the position acquisition unit  60  includes a capacitance type position detection sensor, each of the plurality of detection regions can detect a contact of the detection target, and acquires, as position information of the detection target, a detection region where a contact is detected. The position acquisition unit  60  outputs information of the detection region as the acquired position information to the control unit  24 . Hereinafter, position information of the detection target acquired by the position acquisition unit  60  will be described as “position information”, and a detection region acquired, as position information of the detection target, by the position acquisition unit  60  will be described as an “acquired detection region”. 
     As described above, the syringe pump  1  as the medical apparatus of the present embodiment includes the operation reception unit  40 , the position acquisition unit  60  that can acquire position information of a detection target based on a position of the detection target on the operation reception unit  40 , the detection target being in contact with or proximate to the operation reception unit  40 , and the control unit  24  that identifies, on the basis of a change in the position information acquired by this position acquisition unit  60 , operation input by the detection target. With this arrangement, the syringe pump  1  does not need to be provided with a rotary member that physically rotates as an input device, and therefore can limit reduction in operability even if a foreign substance such as liquid adheres. Moreover, because the syringe pump  1  does not need to be provided with a rotary member, the syringe pump  1  can be configured with a smaller gap. Therefore, cleanability can be improved. 
     [Processing by Syringe Pump] 
       FIG. 4  is a flowchart that illustrates an example of operation position determination processing performed by the syringe pump  1 . The syringe pump  1  determines, with the control unit  24 , the operation position of the detection target on the operation reception unit  40  on the basis of the position information acquired by the position acquisition unit  60 . Here, the above-described position information is information about a detection region on the operation reception unit  40  of the detection target, the information being input from the operation reception unit  40  by the detection target actually being detected on the operation reception unit  40 . Meanwhile, an operation position is a region on the operation reception unit  40 , the operation position being determined on the basis of the above-described position information, and recognized as being input from the operation reception unit  40 , instead of the above-described position information. The control unit  24  performs various kinds of control by regarding not the above-described position information, but the above-described operation position as the information input from the operation reception unit  40 . Details of processing performed by the control unit  24  will be described below. 
     Here, the syringe pump  1  does not recognize, as the above-described operation position, the detection region on the operation reception unit  40  where the detection target has been actually detected, that is, the position information of the above-described detection target. With this arrangement, false operation may be avoided. For example, it is assumed that the operator is operating the operation reception unit  40  with a finger. At this time, for example, the operator performs operation while bringing a fingertip into contact with the operation reception unit  40 . When the operator finishes the operation with respect to the operation reception unit  40  and tries to release the finger from the operation reception unit  40 , in a case in which, for example, another portion other than the fingertip of the finger is in contact with the operation reception unit  40 , the position acquisition unit  60  detects a position in which the another portion is in contact with the operation reception unit  40 . In a case in which the syringe pump  1  performs some processing on the basis of such contact of another portion with the operation reception unit  40 , the processing is unintended by the operator, and therefore the operation is false operation to the operator. Other than a case of releasing the finger, there may be a case in which the syringe pump  1  performs operation unintended by the operator due to contact of the finger with the operation reception unit  40 , which is unintended by the operator. In such a case, the syringe pump  1  may avoid false operation by not recognizing the detection region where the detection target is actually detected as an operation position. 
     Therefore, in order to easily avoid false operation, the syringe pump  1  according to the present embodiment determines an operation position first, and then performs various pieces of processing, such as setting value increase/decrease processing for example, on the basis of the determined operation position.  FIG. 4  illustrates an example of the operation position determination processing performed by the syringe pump  1 . 
     In the operation position determination processing, the syringe pump  1  acquires position information of the detection target by using the position acquisition unit  60  (Step S 101 ). The syringe pump  1  acquires position information at each acquisition time that occurs in a predetermined cycle, for example. Here, it is assumed that the position acquisition unit  60  acquires position information at a cycle of 10 milliseconds. In Step S 101 , the position information of the detection target at a latest acquisition time is acquired. The latest acquisition time is a last acquisition time by the position acquisition unit  60  at a certain time point (for example, present). 
     The position information acquired in Step S 101  is sequentially stored in the storage unit  23  (refer to  FIG. 2 ) of the circuit unit  20  (refer to  FIG. 2 ) along with the acquired time, for example. In this way, the position information is accumulated in time series, for example. 
     The syringe pump  1  determines an operation position on the basis of the position information acquired in Step S 101 . In the present embodiment, the syringe pump  1  determines the operation position at a last acquisition time before the latest acquisition time on the basis of the acquired position information. Here, with reference to Step S 102  to Step S 106  illustrated in  FIG. 4 , an example of a case will be described where the syringe pump  1  determines, on the basis of position information acquired at a latest acquisition time, an operation position at a last acquisition time before the latest acquisition time, that is, at an acquisition time 10 milliseconds ago. In other words, this means that an operation position at the last acquisition time before the latest acquisition time is in an undetermined state, in which the operation position is not determined until position information is acquired at the latest acquisition time, which is one time after the last acquisition time before the latest acquisition time. 
     After acquiring the position of the detection information in Step S 101 , the syringe pump  1  judges whether or not the position information at the latest acquisition time and the position information at the last acquisition time before the latest acquisition time are acquired (Step S 102 ). In a case in which the detection target is detected in, for example, any one area of the area a to area h in the operation reception unit  40  illustrated in  FIG. 3  at the latest acquisition time and the last acquisition time before the latest acquisition time, the syringe pump  1  judges that position information has been acquired (Yes in Step S 102 ). Meanwhile, in a case in which the detection target is not detected in, for example, any one area of the area a to area h in the operation reception unit  40  illustrated in  FIG. 3  at at least one of the latest acquisition time or the last acquisition time before the latest acquisition time, the syringe pump  1  judges that position information is not acquired (No in Step S 102 ). That is, in a case in which the syringe pump  1  judges that position information is not acquired, the operation reception unit  40  is not operated by the operator. 
     In a case in which the syringe pump  1  judges that the position information at the latest acquisition time and the position information at the last acquisition time before the latest acquisition time are acquired (Yes in Step S 102 ), the syringe pump  1  judges whether or not the operation mode of the syringe pump  1  is in a predetermined operation mode (Step S 103 ). 
     Here, an operation mode of the syringe pump  1  will be described. For example, the syringe pump  1  has a plurality of operation modes and operates in any one operation mode among the plurality of operation modes. In the present embodiment, as an example, the syringe pump  1  will be described as having two operation modes, which are a first operation mode and a second operation mode. The syringe pump  1  performs reception processing of input operation in either one operation mode of the first operation mode or the second operation mode according to input operation to the operation reception unit  40  by the finger of the operator, which is as the detection target. 
     The first operation mode is a mode that detects high-speed input by the finger of the operator, which is as the detection target. For example, in a case in which the operator is moving the finger in a state of being in contact with the operation reception unit  40  at a speed exceeding a predetermined threshold, that is, at a high speed, the syringe pump  1  operates in the first operation mode. The first operation mode is performed in a case in which, for example, the operator significantly changes a setting of a parameter, or the like, that is set in the syringe pump  1 . 
     The second operation mode is a mode that detects low-speed input by the finger of the operator, which is as the detection target. For example, in a case in which the operator is moving the finger in a state of being in contact with the operation reception unit  40  at a speed of a predetermined threshold or lower, that is, at a low speed, the syringe pump  1  operates in the second operation mode. The second operation mode is performed in a case in which, for example, the operator tries to adjust a setting of a parameter, or the like, that is set in the syringe pump  1 . 
     The syringe pump  1  stores, in the storage unit  23  for example, a criterion for judging whether input by a finger of the operator, which is as the detection target, is performed at a high speed or low speed. For example, in the example of the operation reception unit  40  described with reference to  FIG. 3 , the syringe pump  1  may judge that the input by the operator is performed at a high speed in a case in which the operator moves the finger by the predetermined number of areas or more within a predetermined time. On the contrary, in the example of the operation reception unit  40  described with reference to  FIG. 3 , the syringe pump  1  may judge that the input by the operator is performed at a low speed in a case in which the operator moves the finger by less than the predetermined number of areas within the predetermined time. 
     For example, the syringe pump  1  may perform processing in the first operation mode in a case in which movement across five or more areas within 50 milliseconds is detected. Furthermore, the syringe pump  1  may perform mode change processing from the second operation mode to the first operation mode in a case in which movement across five or more areas within 50 milliseconds is detected most recently. On the contrary, the syringe pump  1  may perform processing in the second operation mode in a case in which, for example, movement across less than five areas within 50 milliseconds is detected. Furthermore, the syringe pump  1  may perform mode change processing from the second operation mode to the first operation mode in a case in which, for example, movement across less than five areas within 50 milliseconds is detected most recently. It should be noted that a threshold that the syringe pump  1  uses for judging an operation mode may be determined as appropriate according to, for example, a size or shape of the operation reception unit  40 , content of processing performed by the syringe pump  1 , or the like. 
     In Step S 103 , the syringe pump  1  judges whether or not the operation mode is in the second operation mode, for example. As described above, the second operation mode is a mode performed in a case in which the operator tries to adjust a setting. At this time, for example, in a case in which the operator touches an unintended area while operating with an intention to release the finger from the operation reception unit  40 , false operation occurs in which a setting for the syringe pump  1  changes. However, such false operation may be avoided by the operation position determination processing that will be specifically described below. For this reason, it is possible to reduce time and effort required to perform setting again due to the operation unintended by the operator and reduce stress on the operator. 
     In a case in which the syringe pump  1  judges that the operation mode is in the second operation mode (Yes in Step S 103 ), the syringe pump  1  judges whether or not the position information acquired at the latest acquisition time and the position information acquired at the last acquisition time before the latest acquisition time match (Step S 104 ). 
       FIG. 5  illustrates a diagram for describing an example of a method for determining an operation position by the syringe pump  1  in a case in which the operation mode is in the second operation mode at the latest acquisition time.  FIG. 5  illustrates position information acquired by the position acquisition unit  60  and operation positions determined by the control unit  24 . Names of each of the areas illustrated in  FIG. 5  correspond to names of the areas (that is, the detection regions  61   a  to  61   h ) illustrated in  FIG. 3 , for example. Furthermore, the position information and operation positions illustrated in  FIG. 5  are position information and operation positions at the latest acquisition time, the last acquisition time before the latest acquisition time, and the second to last acquisition time before the latest acquisition time. 
     The example illustrated in  FIG. 5  indicates that the area h has been acquired as the position information at the second to last acquisition time before the latest acquisition time, the area a has been acquired as the position information at the last acquisition time before the latest acquisition time, which is 10 milliseconds after the second to last acquisition time before the latest acquisition time, and the area a has been acquired as the position information at a current acquisition time, which is further 10 milliseconds after the last acquisition time before the latest acquisition time. That is, in the example illustrated in  FIG. 5 , the position information at the latest acquisition time and the position information at the last acquisition time before the latest acquisition time match as “area a”. 
     As illustrated in the example in  FIG. 5 , in a case in which the syringe pump  1  judges that the position information acquired at the latest acquisition time and the position information acquired at the last acquisition time before the latest acquisition time match (Yes in Step S 104 ), the syringe pump  1  determines the matched position as the operation position at the last acquisition time before the latest acquisition time (Step S 105 ). That is, in the example illustrated in  FIG. 5 , the syringe pump  1  determines the operation position at the last acquisition time before the latest acquisition time to be “area a”. In this way, in a case in which the same position is acquired at two consecutive acquisition times, it is presumed that the operator is trying to operate so that the finger comes into contact with the position. Therefore, in a case in which the same position is acquired at two consecutive acquisition times, processing reflecting an intention of the operator can be performed by determining the position at a first acquisition time of the two consecutive acquisition times as the operation position, and then performing subsequent processing on the basis of the determined operation position. 
       FIG. 6  illustrates a diagram for describing an example of a method for determining an operation position by the syringe pump  1  in a case in which the operation mode is in the second operation mode at the latest acquisition time. As similar to  FIG. 5 ,  FIG. 6  also illustrates position information acquired by the position acquisition unit  60  and operation positions determined by the control unit  24 . 
     The example illustrated in  FIG. 6  indicates that the area h has been acquired as the position information at the second to last acquisition time before the latest acquisition time, the area a has been acquired as the position information at the last acquisition time before the latest acquisition time, which is 10 milliseconds after the second to last acquisition time before the latest acquisition time, and the area b has been acquired as the position information at a current acquisition time, which is further 10 milliseconds after the last acquisition time before. That is, in the example illustrated in  FIG. 6 , the position information at the latest acquisition time and the last acquisition time before the latest acquisition time are different in “area b” and “area a”. 
     As illustrated in the example in  FIG. 6 , in a case in which the syringe pump  1  judges that the position information acquired at the latest acquisition time and the position information acquired at the last acquisition time before the latest acquisition time do not match (No in Step S 104 ), the syringe pump  1  determines the operation position at the second to last acquisition time before the latest acquisition time as the operation position at the last acquisition time before the latest acquisition time (Step S 106 ). That is, in the example illustrated in  FIG. 6 , the syringe pump  1  determines the operation position at the last acquisition time before the latest acquisition time to be “area g”, which is the operation position of the second to last acquisition time before the latest acquisition time. For example, in a case in which the operator is trying to adjust a parameter, or the like, for the syringe pump  1  in input operation with respect to the operation reception unit  40 , the operator may slowly move the finger as the detection target. At this time, for example, a contact state of the finger with respect to the operation reception unit  40  may become unstable, by which a contact position of the finger on the operation reception unit  40  may be deviated, and the finger may come into contact with an area unintended by the operator. However, as in Step S 106 , in a case in which different positions are acquired at the latest acquisition time and the last acquisition time before the latest acquisition time, processing reflecting an intention of the operator is easier to be performed by not treating positions acquired at the latest acquisition time and at the last acquisition time before the latest acquisition time as the operation position, but treating the operation position at the second to last acquisition time before the latest acquisition time as the operation position at the last acquisition time before the latest acquisition time, even if the finger is in contact with the area unintended by the operator, due to the unstable contact state of the finger. 
     With reference to Step S 103  in  FIG. 4  again, in a case in which the syringe pump  1  judges that the operation mode is not in the second operation mode (No in Step S 103 ), that is, in a case in which the syringe pump  1  judges that the operation mode is in the first operation mode, the syringe pump  1  determines a position indicated by the position information acquired by the position acquisition unit  60  at the last acquisition time before the latest acquisition time as the operation position at the last acquisition time before the latest acquisition time (Step S 107 ). 
       FIG. 7  illustrates a diagram for describing an example of a method for determining an operation position by the syringe pump  1  in a case in which the operation mode is in the first operation mode at the latest acquisition time. As similar to  FIG. 5 ,  FIG. 7  also illustrates position information acquired by the position acquisition unit  60  and operation positions determined by the control unit  24 . 
     The example illustrated in  FIG. 7  indicates that the area h has been acquired as the position information at the second to last acquisition time before the latest acquisition time, the area a has been acquired as the position information at the last acquisition time before the latest acquisition time, which is 10 milliseconds after the second to last acquisition time before the latest acquisition time, and the area b has been acquired as the position information at a current acquisition time, which is further 10 milliseconds after the last acquisition time before the latest acquisition time. 
     As illustrated in the example in  FIG. 7 , in a case in which the syringe pump  1  judges that the operation mode is in the first operation mode that detects high-speed input by the operator (No in Step S 103 ), the syringe pump  1  determines a position indicated by the position information acquired by the position acquisition unit  60  at the last acquisition time before the latest acquisition time as the operation position at the last acquisition time before the latest acquisition time (Step S 107 ). That is, in the example illustrated in  FIG. 7 , the syringe pump  1  determines the operation position at the last acquisition time before the latest acquisition time to be “area a”, which is the position acquired at the last acquisition time before the latest acquisition time. For example, in a case in which the operator is performing high-speed input in input operation with respect to the operation reception unit  40 , an operation position corresponding to input operation to move at a high speed, which is intended by the operator, can be determined by performing the processing like this, and therefore, processing corresponding to the input operation can be performed. 
     With reference to Step S 102  in  FIG. 4  again, in a case in which the syringe pump  1  judges that at least one of the position information at the latest acquisition time or the position information at the last acquisition time before the latest acquisition time is not acquired (No in Step S 102 ), the syringe pump  1  determines the operation position at the last acquisition time before the latest acquisition time to be “no touch” (Step S 108 ). Here, “no touch” indicates that no input has been made from the operation reception unit  40 . That is, in a case of “no touch”, the position information has not been acquired (detected). 
       FIG. 8  illustrates a diagram for describing an example of a method for determining an operation position by the syringe pump  1 . As similar to  FIG. 5 ,  FIG. 8  also illustrates position information acquired by the position acquisition unit  60  and operation positions determined by the control unit  24 . In  FIG. 8 , the operation mode at the latest acquisition time may be either the first operation mode or the second operation mode. 
     The example illustrated in  FIG. 8  indicates that the area h has been acquired as the position information at the second to last acquisition time before the latest acquisition time, the area a has been acquired as the position information at the last acquisition time before the latest acquisition time, which is 10 milliseconds after the second to last acquisition time before the latest acquisition time, and “no touch” has been acquired as the position information at a current acquisition time, which is further 10 milliseconds after the last acquisition time before the latest acquisition time. As illustrated in  FIG. 8 , in a case in which the position acquisition unit  60  does not detect the detection target at the latest acquisition time, the syringe pump  1  determines the operation position at the last acquisition time before the latest acquisition time to be “no touch”, that is, the detection target is not in an operation position on the operation reception unit  40 . That is, although the position acquisition unit  60  actually detects the detection target in the area a as the position information at the last acquisition time before the latest acquisition time, the syringe pump  1  performs processing assuming that the detection target has not been detected at the last acquisition time before the latest acquisition time. With this arrangement, even if the position information acquired by the position acquisition unit  60  at the last acquisition time before the latest acquisition time reflects input operation unintended by a user, the syringe pump  1  does not treat the position information acquired at the last acquisition time before the latest acquisition time as an operation position, and therefore, occurrence of false operation can be avoided. 
       FIG. 9  illustrates a schematic diagram of an example of a state in which a finger as the detection target is released from the operation reception unit  40 . For example, it is assumed that the operator is trying to release the finger in a state of being in contact with the area h from the operation reception unit  40 , as illustrated in  FIG. 9 . At this time, for example, a portion other than the fingertip, such as a first joint of the finger, may come into contact with the area a. In a case in which a portion other than the fingertip is in contact with the area a after the operator releases the fingertip from the area h, the syringe pump  1  may determine that operation from the area h to the area a has been input. In such a case, false operation may occur. However, as described with reference to  FIG. 7 , in a case in which the position acquisition unit  60  does not detect the detection target at the latest acquisition time, the syringe pump  1  determines the operation position at the last acquisition time before the latest acquisition time to be “no touch”, by which occurrence of false operation can be avoided. 
     It should be noted that, for example, in a case in which the operator is trying to release the finger as the detection target from the operation reception unit  40  after bringing the finger into contact with the area a, it is quite unlikely that the finger of the operator has moved from the area h to the area a after further 10 milliseconds, and is off the operation reception unit  40  after 10 milliseconds. In a case in which the operator is trying to release the finger from the operation reception unit  40  after bringing the finger into contact with the area a, the operation is considered usually that the finger is in contact with the area a for at least a few dozen milliseconds, and then released from the operation reception unit  40 . In this case, the position acquisition unit  60  continually detects the detection target in the area a at several acquisition times. That is, the position acquisition unit  60  acquires position information indicating the area a at a plurality of times. Therefore, in this case, the area a is determined as the operation position except for the last one acquisition time among the several acquisition times, and then the operation position is determined to be “no touch” at the last acquisition time before the acquisition time at which “no touch” has been detected. Therefore, with the syringe pump  1  according to the present embodiment, determination of an operation position that meets an intention of the operator is possible even in a case in which the operator is trying to release the finger as the detection target from the operation reception unit  40  after bringing the finger into contact with the area a. 
     It should be noted that, as understood from  FIGS. 5 to 8 , the operation position at the last acquisition time before the latest acquisition time is determined after the position information at the latest acquisition time is acquired. Therefore, the operation position at the latest acquisition time is not determined and remains undetermined at a time when the position information at the latest acquisition time is acquired. The operation position at the latest acquisition time is determined after the position information at a next acquisition time is acquired. 
     The syringe pump  1  can perform various pieces of processing on the basis of the operation position determined in the operation position determination processing illustrated in  FIG. 4 , for example. Here, the setting value increase/decrease processing will be described as an example of the processing performed by the syringe pump  1 . 
       FIG. 10  is a flowchart that illustrates setting value increase/decrease processing performed by the syringe pump  1 . As illustrated in  FIG. 10 , the syringe pump  1  determines the operation position of the detection target on the operation reception unit  40  on the basis of the position information acquired by the position acquisition unit  60  (Step S 201 ). Details of Step S 201  are, for example, as in the operation position determination processing described with reference to  FIG. 4 . Here, it is assumed that an operation position other than “no touch” has been determined. That is, it is assumed that any one of the area a to the area h is determined as the operation position. 
     After that, the control unit  24  identifies the operation input by the detection target on the basis of a change in operation position with time. The control unit  24  increases or decreases a predetermined setting value on the basis of, for example, a change with time in an acquired detection region in the circumferential directions C (refer to  FIG. 3 ). Specifically, the control unit  24  performs the processing in Steps S 202  to S 207  below. 
     The control unit  24  judges whether or not the operation position has changed with time along a first circumferential direction D (refer to  FIG. 3 ), which is one of the circumferential directions C (Step S 202 ). Specifically, the control unit  24  judges whether or not an acquired detection region has changed with time between two detection regions adjacent to each other, along the first circumferential direction D, that is, for example, whether or not the acquired detection region has changed with time from the area a to the area b. 
     In a case in which the control unit  24  judges that the operation position has changed with time along the first circumferential direction D (Yes in Step S 202 ), the control unit  24  increases the predetermined setting value (Step S 203 ). Meanwhile, in a case in which the control unit  24  judges that the operation position has not changed with time along the first circumferential direction D (No in Step S 202 ), the processing proceeds to Step S 204 . 
     The control unit  24  judges whether or not the operation position has changed with time along another direction of the circumferential directions C, that is, a second circumferential direction E (refer to  FIG. 3 ), which is a direction opposite to the first circumferential direction D (Step S 204 ). Specifically, the control unit  24  judges whether or not an acquired detection region has changed with time between two detection regions adjacent to each other, along the second circumferential direction E, that is, for example, whether or not the acquired detection region has changed with time from the area a to the area h. 
     In a case in which the control unit  24  judges that the operation position has changed with time along the second circumferential direction E (Yes in Step S 204 ), the control unit  24  decreases the predetermined setting value (Step S 205 ). Meanwhile, in a case in which the control unit  24  judges that the operation position has not changed with time along the second circumferential direction E (No in Step S 204 ), the processing proceeds to Step S 206 . 
     The control unit  24  judges whether or not the operation position is constant for a predetermined time or longer (Step S 206 ). The predetermined time used in the processing in Step S 206  is previously stored in the storage unit  23  and is, for example, 1 second. 
     In a case in which the control unit  24  judges that the operation position has been constant for the predetermined time or longer (Yes in Step S 206 ), the control unit  24  judges whether or not the operation position has changed immediately before (Step S 207 ). In other words, in the processing in Step S 207 , the control unit  24  judges whether or not the operation position up to immediately before the first operation position used as a basis of the judgement in the processing in Step S 206  has changed. At this time, for example, in a case in which there has been a period in which the position information of the detection target cannot be acquired by the position acquisition unit  60  due to the detection target once leaving the operation reception unit  40 , continuity from the change in the previous operation position is reset. That is, in a case in which the operation position is once determined to be “no touch”, only the position information of the detection target continually acquired by the position acquisition unit  60  again becomes a target of the judgement in the processing in Step S 207 . 
     In a case in which the control unit  24  judges that the operation position has changed immediately before (Yes in Step S 207 ), the control unit  24  increases or decreases the predetermined setting value along either the first circumferential direction D or the second circumferential direction E, whichever the direction in which the operation position has changed with time immediately before (Step S 208 ). Specifically, the control unit  24  increases the predetermined setting value in a case in which the direction in which the operation position has changed with time immediately before is the first circumferential direction D. Meanwhile, the control unit  24  decreases the predetermined setting value in a case in which the direction in which the operation position has changed with time immediately before is the second circumferential direction E. After that, the control unit  24  continues to increase or decrease the predetermined setting value during a period in which the operation position is constant. 
     In a case in which the control unit  24  judges that the operation position has not been constant for the predetermined time or longer (No in Step S 206 ), or judges that the operation position has not changed immediately before (No in Step S 207 ), the control unit  24  does not change the predetermined setting value (Step S 209 ). 
     As described above, the syringe pump  1  increases or decreases the predetermined setting value along a direction in which an operation position has changed with time immediately before in a case in which the operation position has been constant for the predetermined time or longer, and the operation position has changed immediately before, and therefore, the operator can continue to increase or decrease the predetermined setting value along the direction in which the detection target has been moved immediately before without continuing to move the detection target. 
     In the processing in Step S 208 , the control unit  24  may increase or decrease the predetermined setting value by a constant amount of change per unit time. With this arrangement, the operator can estimate remaining time until the predetermined setting value reaches a targeted value by checking, on the display unit  32 , the predetermined setting value that changes at a constant speed, and therefore, can easily set the predetermined setting value to a targeted value. 
     In the processing in Step S 208 , the control unit  24  may increase or decrease the predetermined setting value by an amount of change per unit time corresponding to the amount of change per unit time in the position information that has changed immediately before. In other words, the control unit  24  may determine the amount of change in the predetermined setting value per unit time according to the amount of change per unit time in the position information that has changed immediately before. Specifically, the control unit  24  may increase the amount of change per unit time in the predetermined setting value as the amount of change per unit time in the position information that has changed immediately before is larger. In this way, the syringe pump  1  determines change speed of the predetermined setting value according to change speed of the position information that has changed immediately before, and therefore, can change the predetermined setting value at a speed corresponding to last operation by the operator. 
     Although in the above-described embodiment, the cycle in which the acquisition time occurs is 10 milliseconds, the cycle in which the acquisition time occurs is not limited to 10 milliseconds. The cycle in which the acquisition time occurs may be determined as appropriate according to, for example, a size or shape of the operation reception unit  40 , content of processing performed by the syringe pump  1 , or the like. The cycle in which the acquisition time occurs is preferably, for example, 5 milliseconds to 100 milliseconds, and more preferably 5 milliseconds to 50 milliseconds. By setting the cycle in which the acquisition time occurs to be equal to or less than an upper limit of the above range, in a case in which, for example, a position of the detection target is quickly changed, it is possible to reduce possibility of the control unit  24  erroneously recognizing that a direction in which the detection target actually has rotated is an opposite direction. 
     The present invention is not limited to the configurations specified in the above-described embodiment, and various modifications can be made without departing from the scope of the invention described in the claims. For example, the functions, or the like, included in each component, each step, or the like can be rearranged so as not to logically contradict, and a plurality of components, steps, or the like can be combined into one or divided. 
     Although the processing of increasing or decreasing a predetermined setting value on the basis of change in the operation position with time has been described as processing by the syringe pump  1  in the present embodiment, the processing is not limited to such processing. The processing by the syringe pump  1  may be any processing that identifies, on the basis of the change with time in the operation position, operation input by the detection target, such as switching a selection item, for example. 
     Although the medical apparatus is described as a syringe pump in the present embodiment, the medical apparatus is not limited to this. Examples of other medical apparatuses include a liquid delivery device, such as an infusion pump, a nutrition pump, and a blood pump, an ultrasonic image diagnostic device, an optical diagnostic imaging device, and the like. 
     The present disclosure relates to a medical apparatus and, in particular, to a medical apparatus that receives input operation by an operator. 
     REFERENCE NUMERAL LIST 
     
         
           1  Syringe pump (medical apparatus) 
           11  Placement unit 
           12  Slider 
           13  Pusher fixing unit 
           14  Clamp 
           15  Cylinder flange retainer 
           20  Circuit unit 
           21  Communication unit 
           22  Clocking unit 
           23  Storage unit 
           24  Control unit 
           31  Input button group 
           32  Display unit 
           36  Slider drive unit 
           40  Operation reception unit 
           41  Center point 
           46  Housing 
           50  Syringe 
           51  Cylinder 
           52  Hollow part 
           53  Cylinder flange 
           54  Outlet hole 
           55  Pusher 
           60  Position acquisition unit 
           61   a  to  61   h  Detection region 
         A Extending direction of cylinder of placed syringe 
         B Movable direction of clamp 
         C Circumferential direction 
         D First circumferential direction 
         E Second circumferential direction