Patent Description:
In the related art, as disclosed in Patent Literature <NUM>, there is known a syringe pump type liquid medicine administration device that administers a liquid medicine filled in a liquid medicine container to a living body. The syringe pump type liquid medicine administration device includes a power supply, a drive mechanism, and a control unit, and continuously administers the liquid medicine with high accuracy for a long time by moving a plunger little by little by the drive mechanism.

This type of liquid medicine administration device is refrigerated and stored until they are used by a user. Therefore, the liquid medicine administration device is devised to be extremely downsized so that a refrigerated storage space is small. For example, a power supply capacity is set to a minimum capacity capable of securing a capacity sufficient for normal administration of the liquid medicine after the refrigeration and storage in consideration of a decrease in the power supply capacity due to natural discharge during the refrigerated storage, and the power supply is configured by a button battery having a capacity sufficient to cover the set capacity.

At the time of using the liquid medicine administration device, when a power switch is turned on, the control unit drives the drive mechanism simultaneously, and moves the plunger little by little to administer the liquid medicine to the living body. However, since a small button battery is adopted as the power supply, when a drive device is driven simultaneously, a load on the power supply increases, and a power supply voltage temporarily drops greatly. In the liquid medicine administration device, when the power supply voltage is smaller than a specified value, a safety device operates and all operations are stopped. Therefore, the administration of the liquid medicine is stopped.

An object of the present invention is to provide a liquid medicine administration device capable of reducing a load on a power supply at the start of use.

In order to achieve the object described above, the invention provides a liquid medicine administration device according to independent claim <NUM>. The dependent claim <NUM> provides an advantageous embodiment of the invention.

According to an aspect of the present invention, in the liquid medicine administration device, since the rotation detection unit is started after the motor is started, the load on the power supply at the start of use can be reduced.

Note that, the following description does not limit the technical scope or meaning of terms described in the claims. Furthermore, dimensional ratios in the drawings are exaggerated for convenience of description, and may be different from actual ratios.

<FIG> are views for explaining a liquid medicine administration system <NUM>, a liquid medicine administration device <NUM>, and an administration tool <NUM> according to the present embodiment. <FIG> is a side view of a liquid medicine administration system. <FIG> is a view schematically illustrating a usage example of the liquid medicine administration system. <FIG> is a schematic perspective view of a liquid medicine administration device. <FIG> is a schematic perspective view of a chassis included in a housing and each component member assembled to the chassis. <FIG> is a plan view of the liquid medicine administration device illustrating a state before a plunger is moved forward. <FIG> is a plan view of the liquid medicine administration device illustrating a state after the plunger is moved forward. Note that, an arrow X in each drawing indicates a "longitudinal direction (longitudinal direction of a liquid medicine container <NUM>)" of the liquid medicine administration device <NUM>, an arrow Y indicates a "width direction (depth direction)" of the liquid medicine administration device <NUM>, and an arrow Z indicates a "height direction" of the liquid medicine administration device <NUM>.

The liquid medicine administration system <NUM> is used to administer a liquid medicine into a living body. As illustrated in <FIG>, the liquid medicine administration system <NUM> includes the liquid medicine administration device <NUM> and the administration tool <NUM>.

As illustrated in <FIG>, the liquid medicine administration device <NUM> and the administration tool <NUM> are configured as a patch type used by being stuck on a body surface (skin) H of a user. A body part of the user to which the liquid medicine administration device <NUM> and the administration tool <NUM> are attached is not particularly limited, but is, for example, an abdomen or a femoral part.

For example, the liquid medicine administration system <NUM> can continuously administer a liquid medicine (not illustrated) filled in the liquid medicine container <NUM> included in the liquid medicine administration device <NUM> into the living body for a relatively long time (for example, approximately several minutes to several hours) by a pressing action of a plunger <NUM> (see <FIG>) to be described later. Note that, the liquid medicine administration system <NUM> may intermittently administer the liquid medicine into the living body.

As illustrated in <FIG>, the liquid medicine administration device <NUM> includes the liquid medicine container <NUM> including a cylindrical (barrel-shaped) main body <NUM> filled with the liquid medicine, a housing <NUM> that holds the liquid medicine container <NUM>, the plunger <NUM> that pushes the liquid medicine in the liquid medicine container <NUM>, a drive mechanism <NUM> that advances the plunger <NUM> toward a distal end opening of the liquid medicine container <NUM>, a detection unit <NUM> that detects a portion <NUM> to be detected of the plunger <NUM> and detects completion of feeding of the liquid medicine based on a detection result, and a control unit <NUM> that controls operation of the drive mechanism.

As illustrated in <FIG>, the housing <NUM> includes a box-shaped housing main body 120a in which an accommodation space <NUM> is formed, and a chassis (corresponding to a "support portion") <NUM> which is accommodated in the accommodation space <NUM> of the housing main body 120a and can be fixed to the housing main body 120a.

As illustrated in <FIG>, a window portion 123a that allows the inside of the accommodation space <NUM> to be visually recognized from the outside of the housing <NUM> is formed on an upper surface <NUM> of the housing main body 120a. The window portion 123a is formed by providing a transparent or translucent portion in a part of the housing main body 120a.

A proximal end opening <NUM> for inserting a chassis <NUM> into the accommodation space <NUM> of the housing main body 120a is formed on a proximal end side in a longitudinal direction of the housing main body 120a. The proximal end opening <NUM> of the housing main body 120a is closed by a lid member (not illustrated) in a state in which the chassis <NUM> is accommodated in the accommodation space <NUM>.

A bottom surface <NUM> of the housing main body 120a is provided with a sheet-like sticking portion (not illustrated) that can be stuck to the body surface H of the user. In an initial state before the liquid medicine administration device <NUM> is attached to the user, a peelable protective sheet is attached to a sticking surface of the sticking portion.

As illustrated in <FIG>, the chassis <NUM> holds the liquid medicine container <NUM>, the plunger <NUM>, the drive mechanism <NUM>, the detection unit <NUM>, the control unit <NUM>, and a power supply unit <NUM>.

The liquid medicine container <NUM> is a so-called prefilled liquid medicine container. Therefore, the liquid medicine is filled in a lumen 111a of the main body <NUM> of the liquid medicine container <NUM> in advance. Examples of the liquid medicine include protein preparations, narcotic analgesics, diuretics, and the like.

A sealing member (not illustrated) for preventing leakage of the liquid medicine is disposed in the distal end opening (discharge port) formed at a distal end <NUM> of the liquid medicine container <NUM>. As illustrated in <FIG>, the distal end opening of the liquid medicine container <NUM> is disposed so as to protrude outward from the housing main body 120a. Furthermore, an attachment portion <NUM> that is connected to a tube <NUM> (see <FIG>) to be described later is attached to a distal end portion of the liquid medicine container <NUM>, the distal end portion protruding from the housing main body 120a.

A main body <NUM> of the plunger <NUM> is inserted into the lumen 111a of the main body <NUM> of the liquid medicine container <NUM> (see <FIG> and <FIG>). A gasket <NUM> slidable on an inner wall of the liquid medicine container <NUM> is disposed at a distal end of the main body <NUM> of the plunger <NUM>. The gasket <NUM> liquid-tightly seals a proximal end side of the gasket <NUM> by liquid-tightly bringing an outer circumferential portion of the gasket <NUM> into close contact with an inner circumferential surface of the main body <NUM> of the liquid medicine container <NUM>.

In the present embodiment, the gasket <NUM> is configured to be shrinkable in a direction (longitudinal direction) in which the plunger <NUM> advances when the plunger <NUM> advances in a state in which the gasket <NUM> abuts against a distal end inner wall 112a (see <FIG>) of the liquid medicine container <NUM>. The gasket <NUM> can be made of, for example, a flexible resin material such as a rubber material or an elastomer so as to be shrinkable as described above.

As illustrated in <FIG>, the gasket <NUM> has a tapered shape in which an outer diameter decreases toward a distal end side. Furthermore, the shape of the gasket <NUM> is substantially the same as the shape of the distal end inner wall 112a of the liquid medicine container <NUM>.

As illustrated in <FIG>, the portion <NUM> to be detected is provided at a proximal end of the plunger <NUM>. The portion <NUM> to be detected is used to detect completion of feeding of the liquid medicine by the liquid medicine administration device <NUM>.

The control unit <NUM> controls a liquid medicine feeding operation of the liquid medicine administration device <NUM>. The control unit <NUM> can be configured by, for example, a known microcomputer (electronic circuit element) on which a CPU, a RAM, a ROM, and the like are mounted. The control unit <NUM> integrally controls operations of the drive mechanism <NUM>, the detection unit <NUM>, and the power supply unit <NUM>.

As illustrated in <FIG>, the detection unit <NUM> is disposed in the chassis <NUM>. As illustrated in <FIG>, the detection unit <NUM> detects completion of feeding of the liquid medicine of the liquid medicine administration device <NUM> when the portion <NUM> to be detected included in the plunger <NUM> comes into contact with the detection unit <NUM>. The detection unit <NUM> can be configured by, for example, a known contact-type sensor that transmits a predetermined electric signal when the portion <NUM> to be detected comes into contact with the detection unit <NUM>. The control unit <NUM> acquires information regarding completion of feeding of the liquid medicine by receiving the electric signal from the detection unit <NUM>. Note that, when the plunger <NUM> advances by a predetermined amount, the specific configuration and the like of the detection unit <NUM> are not particularly limited as long as a position of the portion <NUM> to be detected of the plunger <NUM> can be detected.

The power supply unit <NUM> can be configured by, for example, a known button battery or the like. The liquid medicine administration device <NUM> is required to be downsized. Therefore, a small button battery is used as the power supply unit <NUM>.

As illustrated in <FIG>, the drive mechanism <NUM> includes a motor <NUM> that receives a drive current from the power supply unit <NUM> and applies a drive force, a speed reduction mechanism <NUM> that includes a gear or the like transmitting the drive force of the motor <NUM>, an encoder <NUM> that is provided adjacent to the speed reduction mechanism <NUM> and includes a photointerrupter as a rotation detection unit that detects rotation of the motor <NUM> and a slit plate that rotates in accordance with the rotation of the motor <NUM>, and a feed screw <NUM> that is connected to the speed reduction mechanism <NUM>.

The feed screw <NUM> is connected to a proximal end connection portion <NUM> disposed in the vicinity of the proximal end of the plunger <NUM>. The feed screw <NUM> converts a rotational motion transmitted from the speed reduction mechanism <NUM> into a linear motion to advance the plunger <NUM> in the longitudinal direction (X direction). The plunger <NUM> advances toward a distal end side of the liquid medicine container <NUM> to push the liquid medicine from the lumen 111a of the main body <NUM> of the liquid medicine container <NUM> to the tube <NUM> (see <FIG>).

As illustrated in <FIG>, the administration tool <NUM> is configured to be connectable to the liquid medicine administration device <NUM>.

The administration tool <NUM> includes a connector <NUM>, a needle tube <NUM> that punctures the living body, a puncture unit (cannula housing) <NUM>, the tube <NUM>, and a puncture assisting tool <NUM> that assists in puncturing the living body with the needle tube <NUM>.

The connector <NUM> is configured to be connectable to the liquid medicine administration device <NUM> via an attachment portion <NUM> fixed to the connector <NUM>. The attachment portion <NUM> can be connected to the liquid medicine administration device <NUM> by being externally fitted to the attachment portion <NUM> (see <FIG>) provided in the vicinity of the distal end <NUM> of the liquid medicine container <NUM> protruding to the outside of the housing <NUM>.

Inside the attachment portion <NUM>, a connection needle portion (not illustrated) through which the sealing member (not illustrated) disposed at a distal end portion of the liquid medicine container <NUM> can be inserted is disposed. The tube <NUM> communicates with the lumen 111a of the main body <NUM> of the liquid medicine container <NUM> via the connection needle portion.

Inside the puncture unit <NUM>, a flow path (not illustrated) through which the tube <NUM> communicates with a lumen of the needle tube <NUM> is formed. The liquid medicine fed to the puncture unit <NUM> through the tube <NUM> is administered into the living body through the flow path formed inside the puncture unit <NUM> and the needle tube <NUM>.

When the liquid medicine is fed to the user, the puncture assisting tool <NUM> is attached to the puncture unit <NUM>. The puncture assisting tool <NUM> holds an introduction needle (inner needle) <NUM>. The introduction needle <NUM> protrudes from a distal end of the needle tube <NUM> in a state in which the puncture assisting tool <NUM> is attached to the puncture unit <NUM>. By puncturing the living body with the needle tube <NUM> in a state in which the introduction needle <NUM> is inserted into the needle tube <NUM>, the user can insert the needle tube <NUM> into the living body while preventing the needle tube <NUM> from being broken or the like.

The puncture assisting tool <NUM> is removed from the puncture unit <NUM> after puncturing the living body with the needle tube <NUM>. When the puncture assisting tool <NUM> is removed from the puncture unit <NUM>, the introduction needle <NUM> is removed from the lumen of the needle tube <NUM>.

After puncturing the living body with the needle tube <NUM>, the puncture assisting tool <NUM> is removed, and the puncture unit <NUM> is left on the body surface H of the user in a state in which the needle tube <NUM> is indwelled in the living body. When the plunger <NUM> of the liquid medicine administration device <NUM> advances in the liquid medicine container <NUM> in this state, the liquid medicine filled in the liquid medicine container <NUM> is fed to the lumen of the needle tube <NUM> via the tube <NUM> and the flow path of the puncture unit <NUM>.

The introduction needle <NUM> can be formed of, for example, a metal needle. Furthermore, the needle tube <NUM> can be formed of, for example, a resin tubular member (cannula).

Similarly to the liquid medicine administration device <NUM>, the administration tool <NUM> is configured as a patch type used by being stuck on the body surface H of the user. A sheet-like sticking portion (not illustrated) that can be stuck to the body surface H is provided on a contact surface (bottom surface) <NUM> of the puncture unit <NUM> of the administration tool <NUM>. In an initial state before the administration tool <NUM> is attached to the user, a peelable protective sheet is attached to a sticking surface of the sticking portion.

As described above, a schematic configuration of the liquid medicine administration system <NUM>, the liquid medicine administration device <NUM>, and the administration tool <NUM> has been described. The liquid medicine administration device <NUM> is required to be reduced in size and cost in order to facilitate handling at the time of use and to save a storage space at the time of storage. Therefore, a small button battery is adopted as the power supply unit <NUM>. Since there is a limit to supplying large electric power instantaneously, the button battery cannot apply a large load at a time. Therefore, the control unit <NUM> controls the drive mechanism <NUM> as follows.

Next, a specific operation of the control unit <NUM> will be described with reference to <FIG>. <FIG> is a block diagram of a control system of the liquid medicine administration device <NUM>. <FIG> is a diagram schematically illustrating a configuration of the encoder of <FIG>. <FIG> is a graph illustrating temporal changes in an output current and a power supply voltage of the control unit <NUM> at the start of use. <FIG> is an operation flowchart of the control unit <NUM>. <FIG> is a diagram illustrating a temporal change in a power supply voltage of the related art at the start of using the liquid medicine administration device <NUM>. <FIG> is a diagram illustrating a temporal change in a power supply voltage of the present application at the start of using the liquid medicine administration device <NUM>.

As illustrated in <FIG>, the control unit <NUM> is electrically connected to the motor <NUM>. A rotation shaft of the motor <NUM> is mechanically connected to the encoder <NUM> as the rotation detection unit and the speed reduction mechanism <NUM>. As also illustrated in <FIG>, the encoder <NUM> includes a photointerrupter <NUM> including an optical sensor and a slit plate <NUM> in which a large number of slits are radially formed, and detects the rotation of the motor <NUM> by detecting whether or not light passes through the slits of the slit plate <NUM> with the optical sensor of the photointerrupter <NUM>. As illustrated in <FIG>, the photointerrupter <NUM> is electrically connected to the control unit <NUM>. Note that, in the present embodiment, the encoder <NUM> using the photointerrupter <NUM> as the rotation detection unit has been exemplified, but an encoder using a magnetic sensor may be used.

When the control unit <NUM> rotates the motor <NUM>, the speed reduction mechanism <NUM> is driven, and the plunger <NUM> advances in the liquid medicine container <NUM> (see <FIG>). The encoder <NUM> provided adjacent to the speed reduction mechanism <NUM> detects the rotation of the motor <NUM>, and the control unit <NUM> calculates a rotation speed of the motor <NUM> based on the rotation of the motor <NUM> detected by the encoder <NUM>. The rotation of the motor <NUM> detected by the encoder <NUM> is fed back to the control unit <NUM>, and the control unit <NUM> calculates the rotation speed of the motor <NUM> in accordance with the feedback and determines whether or not the motor <NUM> is rotating. Note that, the rotation detection unit can also be incorporated as a part of the speed reduction mechanism <NUM>. Specifically, the slit plate <NUM> is omitted, and instead of this, a large number of slits are radially provided in the gear of the speed reduction mechanism <NUM>, and the rotation of the motor <NUM> is detected by detecting whether or not light passes through the slits provided in the gear by using the optical sensor of the photointerrupter. In this case, the encoder includes the gear of the speed reduction mechanism <NUM> and the photointerrupter. at the start of using the liquid medicine administration device <NUM>, as illustrated in an upper graph of <FIG>, a momentarily excessively large current (starting current that forms a peak current) flows, after that, the current decreases to a steady state current in response to the magnitude of the load, and is stabilized. As illustrated in a lower graph of <FIG>, a voltage of the button battery which is the power supply unit <NUM> decreases momentarily excessively in response to the magnitude of the flowing current, and then the decrease in the voltage is stabilized. When the voltage of the button battery is too low, all the operations of the liquid medicine administration device <NUM> are stopped, and the administration of the medicine is interrupted.

Therefore, as illustrated in an operation flowchart of <FIG>, the control unit <NUM> first drives the motor <NUM> (S100), and when the current of the motor <NUM> decreases to a steady state current in response to the load (S101), starts the photointerrupter <NUM> (S102).

That is, at the start of using the liquid medicine administration device <NUM>, the control unit <NUM> first drives the motor <NUM>, and starts the photointerrupter <NUM> after the current of the motor <NUM> is stabilized, so that the starting currents of the motor <NUM> and the photointerrupter <NUM> are not supplied from the power supply unit <NUM> at a time.

In the related art, since the motor <NUM> and the photointerrupter <NUM> are started at the same timing at the start of using the liquid medicine administration device <NUM>, as illustrated in <FIG>, the power supply voltage drops greatly and the safety device of the liquid medicine administration device <NUM> is easy to be operated. However, as in the present application, when the photointerrupter <NUM> is started after the motor <NUM> is started, as illustrated in <FIG>, the voltage temporarily drops twice, but the power supply voltage does not drop greatly as in the related art, and the safety device is difficult to be operated. That is, the administration of the liquid medicine is not interrupted.

Therefore, the load on the power supply unit <NUM> at the start of using the liquid medicine administration device <NUM> can be reduced. According to this, a battery constituting the power supply unit <NUM> can last longer than the related art. Furthermore, even in a case where the voltage of the battery decreases or internal resistance of the battery increases, the operation range of the battery can be expanded. Furthermore, since electric capacity of the power supply unit <NUM> can be reduced, miniaturization and cost reduction of the liquid medicine administration device <NUM> can be achieved.

Claim 1:
A liquid medicine administration device (<NUM>) comprising: a drive mechanism (<NUM>) that advances a plunger (<NUM>) that pushes a liquid medicine from a liquid medicine container (<NUM>) filled with the liquid medicine toward a distal end opening of the liquid medicine container (<NUM>); and a control unit (<NUM>) that controls operation of the drive mechanism (<NUM>), wherein
the drive mechanism (<NUM>) includes a motor (<NUM>) that applies, to the plunger (<NUM>), a drive force for advancing the plunger (<NUM>), and a rotation detection unit (<NUM>) that detects a rotation of the motor (<NUM>), and
when driving the drive mechanism (<NUM>), the control unit (<NUM>) starts the rotation detection unit (<NUM>) after starting the motor (<NUM>),
characterized in that
the control unit (<NUM>) starts the motor (<NUM>) and, then, after a current supplied to the motor (<NUM>) is stabilized, starts the rotation detection unit (<NUM>).