Needleless syringe

Abstract

The needleless syringe includes: a syringe assembly including a container for housing a substance to be injected, and a driver provided with a mechanism for pressurizing the substance to be injected and injecting the substance to be injected from a nozzle formed at a tip of the container; a housing to which the syringe assembly is attached; a sensor for detecting the pressing force when the nozzle is pressed against an injection target region; and a control circuit for acquiring the pressing force detected by the sensor and performing a first determination that the driver can be operated when the pressing force reaches a first predetermined value or more.

Description

needleless syringe

[0001] The present invention relates to a needleless syringe.

[0002] The needle-free syringe described in Patent Document 1 has a protruding member provided at a first position so as to protrude from an end face of the housing. When a user brings the ejection port into contact with the injection target area to perform an injection, and when the ejection port is pressed and moved to a second position, a voltage is applied to the drive unit to eject the injection target substance. In this way, the needle-free syringe described in Patent Document 1 is configured so that the user's pressing action triggers ignition of the explosive, thereby preventing unintended ejection by the user.

[0003] JP 2015-150401 A

[0004] When a needleless syringe administers an injection solution (injection target substance) to an injection target area in the skin, the administration depth can vary depending on the pressure with which the nozzle is pressed against the skin. For example, when the needleless syringe is pressed with an appropriate pressure equal to or greater than a predetermined value, the injection target substance is administered intradermally (shallowly beneath the skin), whereas if the pressure is too low, the injection target substance may extend beyond the skin and reach the muscle. Here, when a substance exhibiting activity against the injection solution is present in large amounts within the skin, the goal is to inject it intradermally (injection target area). However, if the pressure with which the needleless syringe is pressed against the skin is too low, and the injection solution is administered deep enough to reach the muscle, the effect of the injection target substance may not be fully achieved.

[0005] The technology of the present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a needleless syringe that makes it possible to administer an injection target substance to a desired depth.

[0006] In order to solve the above problems, the needleless syringe of the present disclosure includes: a syringe assembly including a container for storing an injection target substance and a driver equipped with a mechanism for pressurizing the injection target substance and ejecting the injection target substance from a nozzle formed at the tip of the container; a housing to which the syringe assembly is attached; a sensor for detecting a pressing force when the nozzle is pressed against an injection target area; and a control circuit for acquiring the pressing force detected by the sensor, and making a first determination that the driver is operable when the pressing force reaches or exceeds a first predetermined value.

[0007] The needle-free injector may further include a notification unit that notifies a user of the result of the first determination made by the control circuit.

[0008] The control circuit may make a second determination that operation of the driver is not permitted when the pressing force detected by the sensor is equal to or greater than a second predetermined value that is greater than the first predetermined value.

[0009] The needle-free syringe may further include a notification unit that notifies a user of the result of the first determination or the result of the second determination.

[0010] The notification unit issues a first notification to the user when the pressure is equal to or greater than the first predetermined value and less than the second predetermined value, and issues a second notification to the user when the pressure is equal to or greater than the second predetermined value, and the contents of the first notification and the second notification may be different from each other.

[0011] The syringe assembly may be removably attached to the housing, and the sensor may be disposed between the syringe assembly and the housing.

[0012] The needle-free syringe may have a plurality of sensors arranged symmetrically about a central axis of the syringe assembly.

[0013] The needleless syringe may be configured such that a plurality of nozzle tips including an injection port for the injection target substance are arranged around a predetermined axis along the pressing direction against the injection target area, and the plurality of sensors are arranged at positions symmetrical with respect to the predetermined axis.

[0014] The control circuit may store log data indicating the pressing force when the injection target substance is injected in a memory, display the log data on a display unit, or transmit the log data to an external device.

[0015] The control circuit may be capable of setting the first predetermined value based on at least one of a user input, the type of the injection target substance, the type of the container, and an injection target.

[0016] The notification unit may be a display unit that displays the pressure force numerically or graphically.

[0017] When the control circuit determines that the driver is operable, it may drive the driver to eject the injection objective substance from the nozzle.

[0018] The control circuit may notify a user of the upcoming activation during the period from when the control circuit makes the first determination until when the control circuit transmits an activation signal to the driver.

[0019] According to the present disclosure, it is possible to provide a needleless syringe that enables an injection target substance to be administered to a desired depth.

[0020] FIG. 1 is a diagram schematically showing the appearance of a syringe. FIG. 2 is a first cross-sectional view of the syringe. FIG. 3 is a second cross-sectional view of the syringe. FIG. 4 is a diagram showing the configuration of a housing 2 constituting the syringe. FIG. 5 is a diagram showing the schematic configuration of a syringe assembly. FIG. 6 is a cross-sectional view showing the schematic configuration of a container. FIG. 7 is an external view showing the schematic configuration of a container. FIG. 8 is a diagram showing the arrangement of sensors provided on the upper wall of the storage space. FIG. 9 is a diagram showing the configuration of a control circuit. FIG. 10 is a diagram showing a control method executed by the control circuit of the syringe. FIG. 11 is a diagram showing the configuration of a nozzle according to a modified example. FIG. 12 is a diagram showing the arrangement of sensors in the modified example. FIG. 13 is a diagram showing a control method according to a second embodiment.

[0021] First Embodiment A needle-free syringe (hereinafter simply referred to as "syringe") 1 according to an embodiment of the present disclosure will be described below with reference to the drawings. The syringe 1 is a needle-free syringe that uses the combustion energy of gunpowder to inject a projectile corresponding to the injection target substance of the present application into an injection target area (hereinafter simply referred to as the target area), i.e., a device that performs an injection by injecting the projectile into the target area without using a syringe needle.

[0022] Note that the configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of configurations are possible as appropriate within the scope of the present disclosure. In each embodiment, the injection target substance is described as an injection liquid, but this is not intended to limit its form. For example, the injection target substance may be in powder form. The present disclosure is not limited by the embodiments, but is limited only by the claims. In this embodiment, the terms "distal side" and "base side" are used to describe the relative positional relationship in the longitudinal direction of the syringe 1. The "distal side" refers to a position closer to the tip of the syringe 1, i.e., closer to the injection port 77, as described below. The "base side" refers to the direction opposite the "distal side" in the longitudinal direction of the syringe 1, i.e., the direction toward the igniter 22 in the syringe assembly 10 (see FIG. 5, described below).

[0023] <Configuration of syringe> Here, FIG. 1 is a diagram schematically illustrating the appearance of a syringe 1. FIG. 2 is a first cross-sectional view of the syringe 1, which cross section is the AA cross section in FIG. 4 described below. FIG. 3 is a second cross-sectional view of the syringe 1, which cross section is the BB cross section in FIG. 4 described below, which is orthogonal to the AA cross section. FIG. 4 is a diagram illustrating the configuration of a housing 2 constituting the syringe 1, and FIG. 5 is a diagram illustrating the schematic configuration of a syringe assembly 10. The syringe 1 is formed by attaching a syringe assembly 10 to a housing 2. The housing 2 incorporates a control circuit 3 and a sensor 4. A cable 9 ( FIG. 1 ) for supplying a drive current to a driver 20 in the syringe assembly 10 is connected to the housing 2.

[0024] The injection liquid injected into the target area by the syringe 1 is formed by containing a predetermined substance that exerts the efficacy or function expected in the target area in a liquid medium. In the injection liquid, the predetermined substance may be dissolved in the liquid medium, or may simply be mixed without being dissolved.

[0025] Examples of the predetermined substance contained in the injection fluid include, for example, a biologically-derived substance that can be injected into a target area of ​​a living body, or a substance that exhibits a desired physiological activity. Examples of biologically-derived substances include DNA, RNA, nucleic acids, antibodies, and cells. Examples of physiologically-active substances include low-molecular-weight, protein- and peptide-based medicines, vaccines, inorganic substances such as metal particles for thermotherapy and radiotherapy, and various substances with pharmacological or therapeutic effects, including carriers. Furthermore, the liquid medium for the injection fluid may be any substance suitable for administering these predetermined substances into the target area, regardless of whether it is aqueous or oil-based. Furthermore, the viscosity of the liquid medium is not particularly limited, as long as the predetermined substance can be injected using the syringe 1.

[0026] In the syringe 1, the syringe assembly 10 is configured to be detachable from the housing 2. An accommodation space 75 (see FIG. 5 ) formed between a container (accommodating portion) 70 and a plunger 80 included in the syringe assembly 10 is filled with an injection liquid in a preparation stage before the syringe 1 is actuated, and the syringe assembly 10 is a unit that is replaced each time the injection liquid is to be injected. Details of the syringe assembly 10 will be described later.

[0027] Meanwhile, the housing 2 is formed with a grip portion 2a that the user of the syringe 1 grasps for use, and is provided with multiple switches for operating the syringe 1 to inject the injection liquid. The syringe 1 is configured so that the user can grasp and operate it with one hand. The housing 2 will now be described with reference to FIG. 4 . In FIG. 4 , (a) shows the appearance of the housing 2 as viewed from the front, (b) shows the appearance of the housing 2 as viewed from the side, (c) shows the appearance of the housing 2 as viewed from the rear, and (d) shows the appearance of the housing 2 as viewed from above. Here, the “front” refers to the portion located distal to the user when the user grasps the housing 2, which is located on the left side in FIG. 4(b), and the “rear” refers to the portion located proximal to the user, which is located on the right side in FIG. 4(b). Therefore, when a user grasps the housing 2 with one hand, the user's fingertips are placed on the front of the housing 2, which is the distal side, and the user's wrist is positioned close to the rear of the housing 2, which is the proximal side. Moreover, "upper" refers to the area on the base end side of the syringe 1.

[0028] Taking into consideration such user gripping, a grip portion 2a is provided near the front of the housing 2 to make it easier for the user's fingertips to grip. Multiple dimples are formed on the grip portion 2a to improve the grip for the user's fingertips. Furthermore, to further stabilize the user's grip of the housing, the outer periphery on the front side of the grip portion 2a is gently uneven (see FIG. 4(b)), making it easier for the user's index finger and middle finger to grip.

[0029] Furthermore, the housing 2 is provided with two operation switches, a first switch 5 and a second switch 6, for operating the syringe 1. The first switch 5 and the second switch 6 are connected to a control unit such as a microcontroller, as described below. The control unit controls the supply of ignition current to the igniter 22 based on signals from each switch, thereby controlling the operation of the syringe 1. Herein, the first switch 5 is a sliding switch provided at the rear of the housing 2, and its sliding direction is the vertical direction of the housing 2 (the direction connecting the tip and base ends). The first switch 5 is constantly biased upward, and the user can place the syringe 1 in a standby state by continuing to slide the first switch 5 downward (toward the tip) against this biasing force for a certain period of time. Hereinafter, this operation of placing the syringe 1 in a standby state will also be referred to as a start operation. The standby state is a state in which the syringe 1 is ready to eject the injection liquid, and injection is performed if the user performs an additional operation. In addition, in the standby state, the user can release the standby state of the syringe 1 by continuing to slide the first switch 5 downward against its biasing force for a certain period of time.

[0030] Next, the second switch 6 is a push-button switch provided on the upper inclined surface 2b of the housing 2, and the user can push the second switch 6 toward the inside of the housing 2. When the syringe 1 is placed in a standby state by the above-mentioned start operation, the control unit is configured to supply an ignition current to the igniter 22 by pushing the second switch 6. Furthermore, a display unit 8 is provided on the upper inclined surface 2b of the housing 2. The display unit 8 is one form of a notification unit that displays the determination result, etc., of the control circuit 3 to notify the user. The notification unit is not limited to the display unit 8, and may be an indicator, a speaker, a communication module, etc. Furthermore, a connector 2L to which a cable 9 is connected is provided on the upper front inclined surface 2c of the housing 2. In this embodiment, the connector 2L is a USB connector, and the cable 9 is detachable from the housing 2.

[0031] As described above, in this embodiment, power for operating igniter 22 is supplied from an external source via cable 9. Alternatively, a battery for supplying power may be provided inside housing 2. In this case, as long as power remains in the battery, housing 2 can be used repeatedly by replacing syringe assembly 10. When the battery runs out of power, the battery can be replaced or charged.

[0032] An opening 2d for inserting the syringe assembly 10 is provided on the lower surface (tip surface) 2u of the housing 2, and an accommodation space 2e (FIG. 2) for the syringe assembly 10 extends upward from this opening 2d. The accommodation space 2e has a shape corresponding to the syringe assembly 10 and is generally cylindrical in this embodiment. A socket 7 and a sensor 4 are arranged at the upper end of the accommodation space 2e.

[0033] <Syringe Assembly> As shown in Figures 2 and 3, the syringe assembly 10 is attached to the housing 2 to form the syringe 1. As shown in Figure 5, the syringe assembly 10 of this embodiment is an assembly including a driver (driving unit) 20, an attachment 30, a container 70, and a plunger 80. Assembly of the syringe assembly 10 will be described later.

[0034] The driver 20 has a cylindrical body 21. The body 21 has a central portion 21a at its center, a distal end portion 21b at its distal end, and a proximal end portion 21c at its proximal end. The distal end portion 21b, the central portion 21a, and the proximal end portion 21c of the body 21 are connected to each other through their respective internal spaces, and an opening is provided at the distal end of the distal end portion 21b. An igniter 22, which is an electric igniter that burns an ignition charge to generate ejection energy, is attached to the proximal end 21c of the body 21. The igniter 22 has an ignition pin 22b to which an ignition current is supplied from an external source. The ignition pin 22b is coupled to the socket 7 on the housing 2 when the syringe assembly 10 is attached to the housing 2. The attachment state of the igniter 22 to the body 21 is determined so that combustion products generated by activation of the igniter 22 are released toward the central portion 21a of the body 21. That is, the igniter 22 is attached to the base end 21c of the body 21 so that the discharge surface 22c of the combustion products faces the central portion 21a.

[0035] Here, the combustion energy of the ignition charge used in the igniter 22 serves as the energy required for the syringe 1 to inject the propellant into the target area. The ignition charge may preferably be zirconium and potassium perchlorate (ZPP), titanium hydride and potassium perchlorate (THPP), titanium and potassium perchlorate (TiPP), aluminum and potassium perchlorate (APP), aluminum and bismuth oxide (ABO), aluminum and molybdenum oxide (AMO), aluminum and copper oxide (ACO), aluminum and iron oxide (AFO), or a combination of these explosives. These explosives generate high-temperature, high-pressure plasma during combustion immediately after ignition, but exhibit a characteristic whereby the generated pressure drops rapidly when the temperature returns to room temperature and the combustion products condense because they contain no gaseous components. Other explosives may also be used as long as they are capable of injecting the appropriate propellant.

[0036] The body 21 is a cylindrical member, and the internal space of the central portion 21a serves as the combustion chamber 20a. Furthermore, a male thread portion 26 is formed on a portion of the outer surface of the central portion 21a. The male thread portion 26 is configured to threadably mate with a female thread portion 32 of the attachment 30, which will be described later, and the effective lengths of the male thread portion 26 and the female thread portion 32 are determined so as to ensure the necessary connecting force between them. The internal space of the tip portion 21b adjacent to the central portion 21a is formed cylindrical, and a piston 40 is slidably disposed therein.

[0037] When the igniter 22 is activated and combustion products are released into the combustion chamber 20a, the pressure there rises, causing the piston 40 to slide toward the tip end in response to the pressure. In other words, the driver 20 has a mechanism in which the igniter 22 is the actuation source and the piston 40 is the output part.

[0038] As shown in FIG. 5 , the attachment 30 is a component for mounting the driver 20, plunger 80, and container 70. The body 31 of the attachment 30 can be made of a known resin, such as nylon 6-12, polyarylate, polybutylene terephthalate, polyphenylene sulfide, or liquid crystal polymer. These resins may also contain fillers such as glass fiber or glass filler. For example, polybutylene terephthalate may contain 20 to 80% by mass of glass fiber, polyphenylene sulfide may contain 20 to 80% by mass of glass fiber, and liquid crystal polymer may contain 20 to 80% by mass of mineral. The material of the attachment 30 is not limited to resin, but may also be metal or ceramic.

[0039] 5, the driver 20 is disposed in the interior space of the body 31 from the base end to the center. The base end 21c of the driver 20 is located roughly in the base end region of the interior space where the driver 20 is disposed, and the center portion 21a and the tip portion 21b of the driver 20 are located roughly in the tip end region, which has a smaller diameter than the base end. A female screw portion 32 is disposed on the inner wall surface of the body 31, and the female screw portion 32 is formed to threadably engage with the male screw portion 26 provided in the center portion 21a of the driver 20.

[0040] 5, a plunger 80 is disposed in the interior space of the body 31 in a region closer to the tip end than the region where the driver 20 is disposed. The diameter of the region where the plunger 80 is disposed is smaller than the diameter of the region where the tip portion 21b of the driver 20 is disposed, allowing the plunger 80 to slide.

[0041] Furthermore, a portion of the container 70 is generally disposed in a region on the tip side of the internal space of the body 31. The region in which the container 70 is disposed communicates with a region in which the plunger 80 is disposed on its base end side, and its tip side opens to the tip surface of the attachment 30. A female thread portion 36 for attaching the container 70 is formed on the inner wall of the region in which the container 70 is disposed. The female thread portion 36 is threadedly engaged with a male thread portion 74 of the container 70 shown in Figures 6 and 7 described below, thereby realizing the connection between the attachment 30 and the container 70.

[0042] Next, the plunger 80 will be described. The plunger 80 is a member that pressurizes the injection liquid using energy received from the piston 40, and has a plunger rod 81 and a stopper portion 82. The plunger rod 81 is formed, for example, from a resin material that is suitable for pressurization, but is not limited to this and may be formed, for example, from the same type of material as the attachment 30.

[0043] A stopper portion 82 made of an elastic material such as rubber is attached to the tip side of the plunger rod 81. Specific materials that can be used for the stopper portion 82 include, for example, butyl rubber and silicone rubber. Other examples include styrene-based elastomers, hydrogenated styrene-based elastomers, and mixtures thereof with polyolefins such as polyethylene, polypropylene, polybutene, and α-olefin copolymers; oils such as liquid parabens and process oil; and powdered inorganic materials such as talc, cast, and mica. Furthermore, the stopper portion 82 can be made of various rubber materials (especially vulcanized rubbers) such as polyvinyl chloride-based elastomers, olefin-based elastomers, polyester-based elastomers, polyamide-based elastomers, polyurethane-based elastomers, natural rubber, isoprene rubber, chloroprene rubber, nitrile-butadiene rubber, and styrene-butadiene rubber, as well as mixtures thereof. Furthermore, since the stopper portion 82 pressurizes the injection liquid while sliding within the container 70 described below, the surface of the stopper portion 82 and the inner wall surface 75a of the container 70 may be coated or surface-treated with various substances in order to ensure or adjust the slidability between the stopper portion 82 and the inner wall surface 75a of the storage space 75 of the container 70. Examples of such coating agents that can be used include PTFE (polytetrafluoroethylene), silicone oil, diamond-like carbon, and nanodiamond.

[0044] FIG. 6 is a cross-sectional view showing a schematic configuration of the container 70, and FIG. 7 is an external view showing a schematic configuration of the container 70. The container 70 is a member that stores the injection liquid and defines a flow path for injecting the injection liquid pressurized by the plunger 80 into a target area. The container 70 is formed from a material that takes into consideration the pressurization by the plunger and the determination of the flow path. The container 70 of this embodiment is formed from a resin material. Note that the container 70 is not limited to a resin material and can be formed from, for example, the same type of material as the attachment 30.

[0045] The container 70 has a storage space 75 capable of containing the injection liquid and formed so that the stopper portion 82 of the plunger 80 can be advanced, and has a flow path 76 connecting the storage space 75 to an injection port (injection portion) 77 facing the outside of the container 70. Specifically, the container 70 has a cylindrical body portion 70a that defines the storage space 75, and a nozzle 70c that is connected to the tip side of the body portion 70a and defines the flow path 76. Furthermore, the nozzle 70c has a nozzle tip portion 70c2 that includes a part of the flow path 76 on the injection port 77 side, and is configured to have a tapered portion 70c1 that connects the nozzle tip portion 70c2 to the body portion 70a and includes a tip-side outer surface 70c3 that is inclined with respect to the longitudinal central axis of the attachment 30. A displacement prevention device 50, described below, is fitted onto the outer periphery of the nozzle tip portion 70c2.

[0046] In the syringe assembly 10, as shown in FIG. 5 , the tip side of the plunger 80 is fitted into the accommodation space 75 of the container 70 so that the stopper portion 82 of the plunger 80 is slidable within the accommodation space 75 toward the nozzle 70c (toward the tip side). With the plunger 80 fitted into the container 70 in this manner, the space formed between the stopper portion 82 of the plunger 80 and the container 70 serves as a storage space for the injection liquid, i.e., a space in which the injection liquid is sealed. In other words, when the plunger 80 is fitted into the accommodation space 75 in the container 70 at its initial position, the tip surface of the stopper portion 82 and the inner wall surface of the container 70 located distal to the tip surface of the stopper portion 82 define the storage space. The flow path of the container 70 opens to the tip surface 73 of the nozzle 70c, and an injection port 77 is formed therein. Therefore, when the plunger 80 slides within the accommodation space 75 and the injection liquid contained in the accommodation space 75 is pressurized, the injection liquid passes through the flow path 76 and is injected from the injection port 77 .

[0047] The inner diameter of a flow path 76 provided in the container 70 is smaller than the inner diameter of the storage space 75. With this configuration, the highly pressurized injection liquid is injected to the outside from the injection port 77. A male thread portion 74 for attaching the container 70 to the attachment 30 is formed on the outer periphery of the base end side of the container 70. The male thread portion 74 is threadedly engaged with the female thread portion 36 of the attachment 30.

[0048] The tip shape of the stopper portion 82 of the plunger 80 is formed to generally match the tip shape of the storage space 75 defined by the inner wall surface 75a near the portion where the storage space 75 and the flow path 76 connect (the innermost portion of the storage space 75). In the present embodiment, the tip shapes of the stopper portion 82 and the storage space 75 are both tapered, with the diameter decreasing toward the tip. This makes it possible to minimize the gap formed between the stopper portion 82 and the inner wall surface 75a of the container 70 when the plunger 80 slides during injection of the injection liquid and reaches the innermost portion of the storage space 75, thereby preventing the injection liquid from remaining in the storage space 75 and being wasted. However, the shape of the stopper portion 82 is not limited to a specific shape as long as the desired effect is obtained in the syringe 1 of this embodiment. Furthermore, the stopper portion 82 is formed with an outer diameter slightly larger than the storage space 75 of the container 70, so that when it is fitted into the storage space 75 in a radially compressed state, it makes suitable contact with the inner wall surface 75a so as to maintain airtightness between it and the container 70. Note that the outer diameter of the stopper portion 82 does not have to be larger than the storage space 75, and may be approximately the same as the diameter of the storage space 75 as long as appropriate injection of the injection liquid is possible.

[0049] <Assembly of Syringe> In assembling the syringe 1, first, assembly of the syringe assembly 10 will be described. With the stopper portion 82 of the plunger 80 inserted all the way into the storage space 75 of the container 70, the plunger 80 is pulled back, connecting the injection port 77 of the container 70 to the injection liquid. Because the stopper portion 82 and the inner wall surface 75a of the storage space 75 are in close contact with each other, this pulling back operation generates negative pressure within the storage space, allowing the injection liquid to be filled into the storage space 75 through the injection port 77. The amount of pulling back of the plunger 80 at this time is set to a degree that, when the container 70 is attached to the attachment 30 in this state, the plunger 80 (plunger rod 81) protruding from the container 70 reaches the region of the internal space of the attachment 30 where the piston 40 is located.

[0050] When the container 70, with the housing space 75 filled with injection liquid, is attached to the attachment 30, the driver 20 is inserted into the attachment 30 from the proximal end side. The driver 20 is inserted until the distal end surface of the piston 40, located at the distal end portion 21b, reaches the proximal end surface of the plunger 80 within the attachment 30. At this time, the male thread portion 26 provided on the central portion 21a of the driver 20 threadably engages with the female thread portion 32 of the attachment 30, thereby suitably coupling the driver 20 and the attachment 30. At this time, the piston 40 incorporated in the driver 20 is connected to the plunger 80. Note that the connection between the piston 40 and the plunger 80 is not limited to a simple butt connection, and a fitting portion may be provided at the distal end of the piston 40 and the proximal end of the plunger 80 to fit them together.

[0051] When the driver 20 is attached to the attachment 30 to which the container 70 and plunger 80 are attached as described above, the plunger 80 is pushed from the piston 40 toward the tip, and the plunger 80 is positioned at a predetermined position (pre-actuation position) within the container 70. At this time, as the plunger 80 is pushed, excess ejected liquid within the container 70 is discharged from the ejection port 77, leaving a predetermined amount of ejected liquid within the container 70. Note that the volume of the space for accommodating the ejected liquid formed between the plunger 80 positioned at the pre-actuation position and the container 70 is determined to be a volume that ensures an appropriate amount of ejected liquid when the syringe 1 is actuated. Therefore, when the syringe assembly 10 is assembled as described above, the amount of ejected liquid accommodated in the accommodation space 75 of the container 70, i.e., the amount of ejected ejected liquid, is set to a predetermined amount.

[0052] The syringe assembly 10 configured in this manner is attached to the housing 2 by inserting the base end portion into the accommodation space 2e of the housing 2 and fitting the ignition pin 22b of the igniter 22 into the socket 7 on the housing 2 side. At this time, the base end surface 101 of the syringe assembly 10 abuts against the sensor 4. The syringe assembly 10 may be configured to be held so that the syringe assembly 10 does not fall out of the housing 2 when the ignition pin 22b fits into the socket 7 on the housing 2 side. The syringe assembly 10 may also be configured so that the outer wall of the syringe assembly 10 abuts against the inner wall 2h that defines the accommodation space 2e and is tightly fitted therebetween, thereby holding the syringe assembly 10 so that the syringe assembly 10 does not fall out of the housing 2.

[0053] In this manner, the syringe assembly 10 is loaded into the housing 2, and the syringe 1 is prepared for use (see FIGS. 1 to 3). The user holds the housing 2 of the syringe 1 with one hand and slides the first switch 5 located at the rear of the housing 2 for a predetermined period of time to place the syringe 1 in a standby state. The user then presses the nozzle 70c against the target area and, as described below, presses the second switch 6 when notified that the pressing force is appropriate. This activates the igniter 22, pressurizing the ejected fluid via the piston 40 and plunger 80, causing the ejected fluid to be ejected from the ejection port 77 and injected into the target area.

[0054] <Sensor> The sensor 4 detects the pressure when the nozzle 70c of the syringe 1 is pressed against the injection target area and inputs the detected pressure to the control circuit 3. The sensor 4 has, for example, a piezoelectric element, and converts the magnitude of distortion caused by the applied pressure into an electrical signal using the piezoelectric element. The sensor 4 may also be configured to detect a change in capacitance caused by distortion when pressure is applied to a cell having multiple electrodes. The method of detecting pressure by the sensor 4 is not particularly limited, and any method may be used as long as it can input the pressure value to the control circuit 3 as an electrical signal. When the start operation is performed on the first switch 5 and the syringe 1 is in a standby state, the sensor 4 repeatedly detects the pressure at intervals of, for example, several milliseconds to 1 second, and inputs the detected pressure to the control circuit 3.

[0055] The sensor 4 is provided on the upper wall 2f of the accommodation space 2e of the housing 2, located above the accommodation space 2e, and is sandwiched between the base end of the syringe assembly 10 and the upper wall 2f of the accommodation space when the syringe assembly 10 is accommodated in the accommodation space 2e. That is, the sensor 4 is disposed between the container 70 attached to the syringe assembly 10 and the upper wall 2f of the accommodation space of the housing 2. When a user presses the nozzle 70c at the tip of the syringe 10 against an area to be injected, this reaction force is transmitted from the base end of the syringe assembly 10 to the sensor 4, and the sensor 4 detects this reaction force (pressing force).

[0056] FIG. 8 is a diagram showing an example of the arrangement of sensors 4 provided on the upper wall 2f of the storage space. As shown in FIG. 8, multiple sensors 4 (four in this example) are provided and are arranged at positions that are rotationally symmetrical about a predetermined axis 2g. In this embodiment, the predetermined axis 2g coincides with the central axis of the storage space 2e. Furthermore, because the storage space 2e has a shape similar to that of the proximal end portion of the syringe assembly 10, the predetermined axis 2g also coincides with the central axis of the syringe assembly 10 and the central axis of the container 70. That is, the sensors 4 are arranged at positions that are symmetrical about the central axis of the container 70. As a result, when the syringe 1 is pressed perpendicular to the surface of the target area, the detection values ​​of the multiple sensors 4 approximately coincide. However, when the syringe 1 is pressed at an angle relative to the surface of the target area, there is a difference between the detection values ​​of the multiple sensors 4. Therefore, based on the detection values ​​of each sensor 4, the control circuit can determine whether the syringe 1 is correctly pressed perpendicular to the surface of the target area.

[0057] <Control Circuit> FIG. 9 is a diagram showing the configuration of the control circuit 3. The control circuit 3 is a computer having a control unit 132, a memory (storage device) 133, an input / output IF (interface) 134, and a communication IF 135, all of which are interconnected by a connection bus 131. The control unit 132 processes input information and outputs the processing results, thereby controlling the entire device. The control unit 132 is also called a CPU (Central Processing Unit) or an MPU (Micro-processing unit). The control unit 132 is not limited to a single processor, and may have a multiprocessor configuration. It may also have a multi-core configuration having multiple cores in a single chip connected by a single socket.

[0058] The memory 133 may be a main storage device or an auxiliary storage device. The main storage device is used, for example, as a work area for the control unit 132, a storage area for temporarily storing information processed by the control unit 132, and a buffer area for communication data. That is, the main storage device is a storage medium used by the control unit 132 to cache programs and data or as a work area. The main storage device includes, for example, a random access memory (RAM), a read-only memory (ROM), and a flash memory. The auxiliary storage device is a storage medium for storing programs executed by the control unit 132, data used for information processing, operation setting information, and the like. The auxiliary storage device is, for example, a solid state drive (SSD), an erasable programmable read-only memory (EPROM), a flash memory, a USB memory, a memory card, and the like. The auxiliary storage device may store setting information for the syringe 1, determination conditions, a history (log) of detected pressure, and the like.

[0059] The input / output IF 134 is an interface for inputting and outputting data between the control circuit 3 and peripheral devices connected thereto. The input / output IF 134 inputs and outputs data between devices such as a reader / writer that reads and writes data from and to storage media such as flash memory and SSD, an operation unit, a display unit, a speaker, and a sensor. The operation unit is an input unit that inputs information to the control circuit 3 through user operation, such as operation buttons, selection keys, or a touch panel. The display unit 8 is an output unit that displays and outputs information such as the determination results of the control unit 132 to the user. The touch panel may be arranged superimposed on the display area of ​​the display device and configured to detect touch operations on icons displayed on the display device and input the information to the control circuit 3. The operation unit of this embodiment includes a first switch 5 and a second switch 6. The operation unit may also input and set first and second predetermined values ​​to the control circuit 3 through user operation. In addition, the control circuit 3 may store statistical data and data tables in memory in advance, and when the user operates the operation unit to input information about the substance to be injected (type of medicinal liquid to be used, amount, type of container, etc.) and information about the person to be administered (gender, age, body fat percentage, administration location, etc.), the control circuit 3 may set the first predetermined value and the second predetermined value based on this information.

[0060] The communication IF 135 is an interface (communication module) that communicates with other devices via a communication line (network), and is also referred to as a CCU (Communication Control Unit). The communication IF 135 of this embodiment includes a wired IF 51 that performs wired communication and a wireless IF 52 that performs wireless communication. The wired IF 51 communicates with other devices via, for example, a cable 9. The wireless IF 52 communicates with other devices via, for example, a WLAN. The wireless IF 52 of this embodiment employs a communication line defined by IEEE 802.11, but is not limited thereto, and may employ, for example, a communication line based on Bluetooth (registered trademark).

[0061] In the control circuit 3, the control unit 132 realizes the functions described below based on an application program. That is, the control unit 132 realizes the required functions using software. However, some or all of the functions may be realized by hardware such as a dedicated large-scale integration (LSI) such as a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a logic circuit, or other digital circuit. Furthermore, at least part of the hardware may include an analog circuit. The control unit 132 may be configured such that one processor functions as multiple processing units, or may be configured such that multiple processors function as one processing unit.

[0062] The control circuit 3 acquires the pressure detected by the sensor 4, and when the pressure reaches or exceeds a first predetermined value, makes a first determination that the driver 20 is operable. Furthermore, when the pressure detected by the sensor 4 exceeds a second predetermined value that is greater than the first predetermined value, the control circuit 3 makes a second determination that the driver 20 is not operable. The control circuit 3 notifies the user by displaying the results of the first and second determinations on the display unit 8. Note that the notification to the user is not limited to a display on the display unit 8, but may also be a notification by sound output from a speaker, information transmission from the CCU to a user terminal, vibration by a vibrator, or the like.

[0063] The control circuit 3 issues a first notification to the user when the pressure is equal to or greater than a first predetermined value but not exceeding a second predetermined value. The control circuit 3 issues a second notification to the user when the pressure is equal to or greater than a second predetermined value or when the pressure is equal to or less than the first predetermined value. The control circuit 3, for example, displays text such as "Operable" as the first notification and "Inoperable" as the second notification on the display unit 8. The control circuit 3 may also output these "Operable" and "Inoperable" messages as audio messages from a speaker. The control circuit 3 may also use an indicator to indicate a color corresponding to the notification, such as "green" for the first notification and "red" for the second notification. In this way, by differentiating the content of the first notification and the second notification, the control circuit 3 can accurately notify the user that the injection pressure has been reached (first notification) and that injection is not possible due to excessive or insufficient pressure (second notification).

[0064] <Control Method> Fig. 10 is a diagram showing a control method executed by the control circuit 3 of the syringe 1. When the user performs a start operation and the syringe 1 enters a standby state, the control circuit 3 starts the processing of Fig. 10.

[0065] In step S10, the control circuit 3 acquires information on the injection objective substance and information on the injection target. For example, the control circuit 3 acquires information on the injection objective substance and information on the injection target input by the user via the operation unit. The control circuit 3 may also acquire information on the injection objective substance and information on the injection target from another device via the cable 9 or a wireless communication line.

[0066] In step S20, the control circuit 3 sets a first predetermined value and a second predetermined value based on the information on the injection objective substance and the information on the injection target acquired in step S10. The second predetermined value is a value greater than the first predetermined value, for example, 60 N. However, the first predetermined value may be 3 N to 10 N, and the second predetermined value may be 30 N to 80 N.

[0067] In step S30, the control circuit 3 acquires the pressure detected by the sensor 4 and determines whether the pressure reaches or exceeds a first predetermined value to determine whether the driver 20 is operable. If the pressure reaches or exceeds the first predetermined value and the determination is affirmative, the control circuit 3 proceeds to step S40, and if the determination is negative, the control circuit 3 proceeds to step S100.

[0068] In step S40, the control circuit 3 acquires the pressure detected by the sensor 4 and determines whether the pressure is equal to or greater than a second predetermined value, or, after it has been determined that the pressure is equal to or greater than the first predetermined value, whether the pressure falls below the first predetermined value, thereby determining whether operation of the driver 20 is impossible. If the control circuit 3 determines that the pressure is less than the second predetermined value, it proceeds to step S50. If the control circuit 3 determines that the pressure is equal to or greater than the second predetermined value, it proceeds to step S110.

[0069] In step S50, the control circuit 3 determines whether the syringe 1 is being pressed at an angle based on the detection values ​​of the multiple sensors 4. If the difference between the detection values ​​of the sensors 4 is less than a predetermined value, the control circuit 3 determines that the syringe 1 is not being pressed at an angle and is being pressed appropriately, and proceeds to step S60. On the other hand, if the difference between the detection values ​​of the sensors 4 is equal to or greater than the predetermined value, the control circuit 3 determines that the syringe 1 is being pressed at an angle, and proceeds to S120.

[0070] In step S60, the control circuit 3 displays, as a first notification, information indicating that ejection is possible (ejection possible information) on the display unit 8. Examples of the ejection possible information include text such as "ejection possible," a numerical value of the pressing force, or a graph showing the pressing force. The first notification may also be, for example, changing the displayed text or background color to a specific color (e.g., green), outputting a specific sound, or a combination of these.

[0071] In step S70, the control circuit 3 determines whether or not the second switch 6 has been pressed, and if the determination is affirmative, the process proceeds to step S80, and if the determination is negative, the process proceeds to step S30.

[0072] In step S80, the control circuit 3 supplies a drive current (ignition current) to the driver 20 to operate the driver 20.

[0073] In step S90, the control circuit 3 acquires the pressure detected by the sensor 4 during injection and stores the detected value of the pressure as a log in the memory 133. Alternatively, the control circuit 3 may display the log data on the display unit 8 or transmit the log data to an external device. This allows the control circuit 3 to later check whether the injection was performed with an appropriate pressure, etc.

[0074] If a negative determination is made in step S30 and the process proceeds to step S100, the control circuit 3 displays insufficient pressure information on the display unit 8 as a notification that injection is not possible due to insufficient pressure. Examples of insufficient pressure information include text such as "insufficient pressure," a value of the pressure, or a graph showing the pressure. The notification of insufficient pressure is not limited to these displays, and may also be made by changing the displayed text or background color to a specific color (e.g., yellow), by outputting an error sound, or by a combination of these.

[0075] If the determination in step S40 is affirmative and the process proceeds to step S110, the control circuit 3 determines that the pressure is outside the specified range, and therefore causes the display unit 8 to display ejection-prohibited information as a second notification. Examples of the ejection-prohibited information include text such as "ejection not permitted," a pressure value, or a graph showing the pressure. The second notification may also be, for example, a specific color (e.g., red) for the displayed text or background, a sound error, or a combination of these.

[0076] If the determination in step S50 is affirmative and the process proceeds to step S120, the control circuit 3 determines that the syringe 1 has been pressed at an angle and causes the display unit 8 to display tilt information indicating that the syringe 1 is tilted. Examples of tilt information include text such as "too tilted" and an icon indicating that the syringe 1 is tilted. Notification of tilt may also be, for example, by changing the displayed text or background color to a specific color (e.g., blue), by outputting an error sound, or by a combination of these. Furthermore, guidance indicating how to reposition the syringe may be displayed on the display unit 8.

[0077] <Effects of the embodiment> (1) The syringe 1 of the present embodiment makes a first determination that the driver 20 is operable when the pressing force against the injection target area reaches or exceeds a first predetermined value. As a result, the syringe 1 of the present embodiment can inject the injection objective substance while being pressed against the injection target area with an appropriate pressing force, and can administer the injection objective substance to the desired depth.

[0078] (2) The syringe 1 further includes a notification unit that notifies the user of the result of the first determination made by the control circuit 3. This allows the syringe 1 to allow the user to understand the appropriate pressing force.

[0079] (3) When the pressing force detected by the sensor 4 is equal to or greater than a second predetermined value that is greater than the first predetermined value, the control circuit 3 of the syringe 1 makes a second determination that operation of the driver 20 is not permitted. This enables the syringe 1 to perform injection with an appropriate pressing force, preventing damage to the container, etc., reducing the load on the syringe 1, and avoiding malfunctions.

[0080] (4) The syringe 1 further includes a notification unit that notifies the user of the result of the first determination or the result of the second determination. This allows the user to know that the pressing force of the syringe 1 is excessive, making it possible to avoid damage or malfunction due to excessive pressing force.

[0081] (5) The notification unit of the syringe 1 issues a first notification when the pressing force is equal to or greater than a first predetermined value and less than a second predetermined value, and issues a second notification when the pressing force is equal to or greater than a second predetermined value. The contents of the first notification and the second notification are different from each other. This allows the syringe 1 to allow the user to understand the appropriate range of pressing force.

[0082] (6) The syringe assembly 10 is detachably attached to the housing 2, and the sensor 4 is disposed between the syringe assembly 10 and the housing 2. This prevents the sensor 4 from directly touching the area to be injected, allowing for hygienic injections.

[0083] (7) In the syringe 1, multiple sensors 4 are arranged at positions symmetrical about the central axis of the syringe assembly 10. This allows the sensors 4 to detect the inclination of the syringe 1 relative to the injection target area. By notifying the user of this inclination, the user can be made aware of the inclination and can perform the injection in the correct position, with the syringe 1 perpendicular to the surface of the injection target area.

[0084] (8) The control circuit 3 stores log data indicating the pressure applied when the injection target substance was injected in memory, displays the log data on the display unit 8, or transmits the log data to an external device. This allows the syringe 1 to keep a record of the pressure applied during injection, and enables the user to determine the validity of the injection in case of later verification.

[0085] (9) The control circuit 3 can set the first predetermined value based on at least one of a user input, the type of injection target substance, the type of container, and the injection target. This allows the user to finely set each predetermined value in the syringe 1 by operating the operation unit.

[0086] (10) The notification unit of the syringe 1 is a display unit that displays the pressing force numerically or graphically. This allows the user to accurately grasp the pressing force numerically or graphically.

[0087] <Modification> FIG. 11 is a diagram showing the configuration of a nozzle 70c according to a modification, and FIG. 12 is a diagram showing the positional relationship between the sensor 4 and the nozzle tip portion 70c2 in the modification. FIG. 12 shows the upper wall 2f of the storage space 2e, to which the sensor 4 is attached, overlapping with the nozzle tip portion 70c2, as seen from the tip side of the syringe assembly 10 loaded in the storage space 2e. Note that FIG. 12 omits other components such as the socket 7, the body 21, and the attachment 30. Also, in FIG. 12 , the nozzle tip portion 70c2 is indicated by a two-dot chain line. This modification differs from the first embodiment in that it is configured to include multiple nozzle tip portions 70c2. Note that the other configuration is the same as in the first embodiment, and therefore, the same elements are designated by the same reference numerals, and repeated description will be omitted.

[0088] As shown in Fig. 11, a plurality of nozzle tip portions 70c2 are provided at the tip of the nozzle 70c in this modification. While Fig. 11 shows an example in which three nozzle tip portions 70c2 are provided, the present invention is not limited to this, and the number of nozzle tip portions 70c2 may be two, four, or more. The plurality of nozzle tip portions 70c2 are arranged around a predetermined axis 70x along the pressing direction of the syringe 1.

[0089] As shown in FIG. 12 , the predetermined axis 70x coincides with the predetermined axis 2g located at the center of the multiple sensors 4. That is, the multiple sensors 4 are arranged at positions that are rotationally symmetrical about the predetermined axis 70x. This allows the syringe of this modified example to detect the inclination of the syringe 1 with respect to the injection target area. Then, by notifying the user of this inclination, the user can perform the injection in the correct position, with the syringe 1 perpendicular to the surface of the injection target area.

[0090] Second Embodiment This embodiment differs from the first embodiment in that injection is not triggered by pressing the second switch 6, but rather the control circuit 3 initiates injection when an injection is possible. Note that other configurations are the same as those of the first embodiment, and therefore the same elements are designated by the same reference numerals and will not be described again.

[0091] FIG. 13 is a diagram showing a control method according to the second embodiment. In FIG. 13, the processes from step S10 to step S50 are the same as those in FIG. 10. If it is determined in step S50 that the syringe is not tilted and the process proceeds to step S60A, the control circuit 3 outputs information (pre-emptive information) notifying the user of the upcoming injection. For example, this information is displayed on the display unit 8. Examples of the output of the pre-emptive information include displaying text such as "Injection timer starts in 5 seconds" or "Ready for injection," or a countdown to injection. Furthermore, the output of the pre-emptive information may include, for example, changing the displayed text or background color to a specific color (e.g., purple), outputting a specific sound or voice, or a combination of these.

[0092] In step S70A, the control circuit 3 determines whether a predetermined time has elapsed since the first notice was given, and if the determination is affirmative, the process proceeds to step S80, and if the determination is negative, the process proceeds to step S30. Note that the processes from step S80 to step S120 are the same as those in FIG. 10.

[0093] In this way, when the control circuit 3 of this embodiment determines that the driver 20 is operable, it drives the driver 20 to inject the injection target substance from the nozzle 70 c. This allows the syringe 1 of this embodiment to automatically operate when the conditions for injection are met, enabling injections with good reproducibility.

[0094] Furthermore, the control circuit 3 of this embodiment notifies the user of its upcoming activation during the period from when the first determination is made until when the activation signal is sent to the driver 20. This allows the syringe 1 of this embodiment to notify the user of the activation timing, allowing the user to prepare themselves and enabling a successful injection.

[0095] 1: Syringe 2: Housing 3: Control circuit 4: Sensor 5: First switch 6: Second switch 7: Socket 8: Display 9: Cable 10: Syringe assembly 20: Driver 20a: Combustion chamber 21: Body 21a: Center portion 21b: Tip portion 21c: Base end portion 22: Igniter 22b: Ignition pin 22c: Discharge surface 26: Male thread portion 30: Attachment 31: Body 32: Female thread portion 36: Female thread portion 40: Piston 50: Position prevention device 70: Container 70a: Body portion 70c: Nozzle 70c1: Tapered portion 70c2: Nozzle tip portion 70c3: Tip side outer surface 70x: Predetermined axis 73: Tip surface 74: Male thread portion 75: Storage space 75a: Inner wall surface 76: Flow path 77: Injection port 80: Plunger 81: Plunger rod 82: Stopper portion 101: Base end surface 131: Connection bus 132: Control unit 133: Memory 134: Input / output IF 135: Communication IF 51: Wired IF 52: Wireless IF

Claims

1. A needleless syringe comprising: a syringe assembly including a container for storing a substance for injection and a driver equipped with a mechanism for pressurizing the substance for injection and ejecting the substance for injection from a nozzle formed at the tip of the container; a housing to which the syringe assembly is attached; a sensor for detecting a pressure force when the nozzle is pressed against an area to be injected; and a control circuit for acquiring the pressure force detected by the sensor, and making a first determination that the driver is capable of operation when the pressure force reaches or exceeds a first predetermined value.

2. The needle-free syringe according to claim 1, further comprising a notification unit that notifies a user of the result of said first determination by said control circuit.

3. The needle-free syringe as described in claim 1, wherein the control circuit makes a second judgment that operation of the driver is not possible when the pressing force detected by the sensor is equal to or greater than a second predetermined value that is greater than the first predetermined value.

4. The needle-free syringe according to claim 3, further comprising a notification unit that notifies a user of the result of the first judgment or the result of the second judgment.

5. The needle-free syringe according to claim 4, wherein the notification unit issues a first notification to the user when the pressing force is equal to or greater than the first predetermined value and less than the second predetermined value, and issues a second notification to the user when the pressing force is equal to or greater than the second predetermined value, and the contents of the first notification and the second notification are different from each other.

6. The needle-free injector according to claim 1, wherein the syringe assembly is removably attached to the housing, and the sensor is disposed between the syringe assembly and the housing.

7. The needle-free syringe according to claim 6, wherein a plurality of said sensors are disposed at positions symmetrical about a central axis of said syringe assembly.

8. The needle-free syringe according to claim 6, wherein the nozzle tip including the injection target substance ejection port is arranged in a plurality of positions around a predetermined axis along the pressing direction against the injection target area, and the plurality of sensors are arranged in positions symmetrical with respect to the predetermined axis.

9. The needle-free syringe according to claim 1, wherein the control circuit stores log data in a memory indicating the pressing force when the injection target substance is ejected, displays the log data on a display unit, or transmits the log data to an external device.

10. The needleless syringe of claim 1, wherein the control circuit is capable of setting the first predetermined value based on at least one of a user input, a type of the injection target substance, a type of the container, and an injection target.

11. The needle-free syringe according to claim 2, 4 or 5, wherein the notification unit is a display unit that displays the pressing force numerically or graphically.

12. A needle-free syringe as described in any one of claims 1 to 10, wherein when the control circuit determines that the driver is operable, it drives the driver to eject the injection target substance from the nozzle.

13. The needle-free injector according to claim 12, wherein a notice of activation is given to a user after the control circuit makes the first determination and before transmitting an activation signal to the driver.