Drip probe and measurement device

Abstract

This drip probe attached to a drip chamber comprises: an illumination unit that emits a plurality of first light components; and an imaging unit provided at a position facing the illumination unit across the drip chamber. The imaging unit includes: a first light converter that converts the optical paths of a plurality of second light components among the plurality of first light components emitted from the illumination unit and emits parallel light, the plurality of second light components entering the drip chamber, propagating in parallel with each other inside the drip chamber, being emitted from the drip chamber, and being at least partially refracted when emitted from the drip chamber; a light-converging element that converges the parallel light emitted from the first light converter; and an image sensor that converts the light emitted from the light-converging element into an image.

Description

Drip probe and measuring device

[0001] The present disclosure relates to a drip probe and a measuring device.

[0002] Patent Document 1 discloses a device that irradiates a drip cylinder with parallel light using a light emitting element and a lens, condenses the light that has passed through the drip cylinder with the lens, and receives the light with a light receiving element.

[0003] Patent Document 2 discloses a device that collimates light from a light source and irradiates droplets falling from a dropping nozzle, and detects a generated shadow image with an image sensor arranged on the opposite side of the light source across the drip cylinder. A beam expander using two collimator lenses is arranged between the light source and the drip cylinder. A cylindrical convex lens that forms a linear condensing beam on the focal plane is arranged between the drip cylinder and the image sensor.

[0004] Japanese Patent Application Laid-Open No. 2002-191692, Japanese Patent Application Laid-Open No. 2017-072497

[0005] As a basic configuration of an imaging system using parallel light for drip monitoring, an example as shown in FIG. 9 can be considered. In this example, the drip probe 31A includes a light source 41, an optical element 42, a condensing element 43, and a camera 44. The light source 41 and the optical element 42 irradiate the drip cylinder 20 with parallel light, the light that has passed through the drip cylinder 20 is condensed by the condensing element 43, and imaged by the camera 44.

[0006] As shown in FIG. 10, in the above-described configuration, due to the respective light refractions of the first portion 21 where parallel light enters the drip cylinder wall and the second portion 22 where the light that has passed through the drip cylinder 20 exits, the parallelism of the incident light is lost as it goes to the periphery. As a result, it may not be possible to accurately image the peripheral portion of the droplet.

[0007] As shown in FIG. 11, in the above-described configuration, when imaging the parallel outgoing light from the second portion 22, the falling droplet 80B on the right side forms a larger shadow than the falling droplet 80A on the left side. That is, the subject appears smaller as it goes to the left. As a result, it may not be possible to image the shadow of the droplet with the same size regardless of the droplet's falling position.

[0008] Neither the apparatus disclosed in Patent Document 1 nor Patent Document 2 addresses the refraction that occurs in the drip chamber wall as described above.

[0009] The purpose of this disclosure is to provide an intravenous probe and measuring device that can image droplets inside a drip chamber with high precision.

[0010] Some aspects of this disclosure are shown below.

[0011] [1] An intravenous drip probe to be attached to a drip chamber, comprising: an illumination unit that emits a plurality of first light components; a first optical converter provided at a position opposite the illumination unit across the drip chamber, which converts the optical paths of a plurality of second light components that are incident on the drip chamber from the plurality of first light components emitted from the illumination unit, travel parallel to each other inside the drip chamber, are emitted from the drip chamber, and are at least partially refracted when emitted from the drip chamber, thereby emitting parallel light; a focusing element that focuses the parallel light emitted from the first optical converter; and an imaging unit including an image sensor that converts the light emitted from the focusing element into an image.

[0012] [2] The infusion probe according to [1], wherein the first optical transducer is an aspherical lens.

[0013] [3] The drip probe according to [1] or [2], wherein the illumination unit includes a light source and a second photoconverter that converts the optical paths of a plurality of light components contained in the light irradiated by the light source and emits the plurality of first light components.

[0014] [4] The drip probe according to [3], wherein the second photoconverter emits a plurality of light components as the plurality of first light components, which travel non-parallel to each other before being incident on the drip chamber, are refracted in part when incident on the drip chamber, and travel parallel to each other inside the drip chamber after being incident on the drip chamber.

[0015] [5] The drip probe according to [4], wherein the illumination unit further includes an optical element disposed between the light source and the second photoconverter, which emits the light irradiated by the light source as parallel light, and the second photoconverter converts the optical paths of a plurality of light components contained in the parallel light emitted from the optical element to emit the plurality of first light components.

[0016] [6] The infusion probe according to [3], wherein the second photoconverter diffuses the light irradiated by the light source and emits diffused light containing the plurality of first light components.

[0017] [7] The drip probe according to [1] or [2], wherein the illumination unit includes a light source that emits diffuse light containing the plurality of first light components.

[0018] [8] The intravenous drip probe according to any one of [1] to [7], wherein the imaging unit further includes a pinhole positioned between the light-collecting element and the image sensor at a position corresponding to the focal point of the light-collecting element.

[0019] [9] The intravenous drip probe according to any one of [1] to [7], wherein the imaging unit further includes a lens positioned between the light-gathering element and the image sensor at a position corresponding to the focal point of the light-gathering element.

[0020]

[10] A measuring device comprising an intravenous drip probe as described in any one of items [1] to [9], and a controller that acquires an image from the intravenous drip probe, estimates the volume of the falling droplets contained in the image, and calculates the flow rate of the drip chamber based on the obtained estimation result.

[0021] According to this disclosure, it is possible to image droplets inside a drip chamber with high accuracy.

[0022] This figure shows the configuration of the infusion system and measuring device according to the first embodiment. This is a horizontal cross-sectional view showing the configuration of the drip probe according to the first embodiment. This figure shows examples of the first and second optical converters of the drip probe according to the first embodiment. This is an example of an image taken with the drip probe according to the first embodiment. This is a horizontal cross-sectional view showing the configuration of the drip probe according to the second embodiment. This figure shows an example of the first optical converter of the drip probe according to the second embodiment. This figure shows an example of applying a pinhole to the drip probe according to the second embodiment. This figure shows an example of applying a small-diameter lens to the drip probe according to the second embodiment. This is a horizontal cross-sectional view showing the configuration of the drip probe according to a comparative example. This figure shows one practical problem with the drip probe according to the comparative example. This figure shows another practical problem with the drip probe according to the comparative example.

[0023] Several embodiments of this disclosure will be described below with reference to the figures.

[0024] In each figure, identical or corresponding parts are denoted by the same reference numerals. In the description of each embodiment, the description of identical or corresponding parts will be omitted or simplified as appropriate.

[0025] A first embodiment, which is one embodiment of this disclosure, will be described below.

[0026] Referring to Figure 1, the configuration of the infusion system 10 according to this embodiment will be described.

[0027] The infusion system 10 is a medical device used to administer liquids such as nutritional supplements or medicinal solutions to a living body, such as a patient. The infusion system 10 forms an infusion line for transporting the liquid to the living body.

[0028] The infusion system 10 includes a drip chamber 20, an infusion container 11, a connector 12, multiple infusion tubes 13, a clamp 14, and an infusion pump 15.

[0029] The infusion container 11 contains a liquid. The infusion container 11 is, for example, an infusion bag that contains a drug such as physiological saline. The connector 12 can be connected to an indwelling needle placed in the body. Multiple infusion tubes 13 connect the components of the infusion line, namely the infusion container 11, the drip chamber 20, and the connector 12. The clamp 14 and infusion pump 15 are attached to the infusion tubes 13 connecting the drip chamber 20 and the connector 12 in order to adjust the flow rate of the liquid flowing through the infusion line.

[0030] The drip chamber 20 dispenses the liquid transported from the upstream of the infusion line and stores it in its internal drip chamber. The drip chamber 20 then discharges the liquid stored in the drip chamber downstream of the infusion line. The flow rate of the liquid supplied from the infusion container 11 is visible through the drip chamber 20. The drip chamber 20 comes in, for example, an adult version with a flow rate of 20 drops / mL, i.e., 50 μL / drop, and a pediatric version with a flow rate of 60 drops / mL, i.e., 16.7 μL / drop. At least the portion of the peripheral wall of the drip chamber 20 located above the liquid level of the stored liquid in the drip chamber is made of a light-transmitting material.

[0031] Referring to Figure 1, the configuration of the measuring device 30 according to this embodiment will be described.

[0032] The measuring device 30 comprises an intravenous drip probe 31 and a controller 32.

[0033] The drip probe 31 can be attached to the drip chamber 20. The drip probe 31 is used to detect droplets falling inside the drip chamber 20 when it is attached around the drip chamber 20. Specifically, the drip probe 31 is used to detect droplets falling inside the drip chamber 20 when it is attached so as to clamp the peripheral wall of the drip chamber 20 and is positioned above the liquid level of the stored liquid. The detailed configuration of the drip probe 31 will be described later.

[0034] In this embodiment, the controller 32 is built into the infusion pump 15 as shown in Figure 1, but it may also be integrated with the drip probe 31. The controller 32 is, for example, a computer such as a microcomputer, and has a processor such as a CPU or GPU and memory such as RAM, ROM, or flash memory. "CPU" is an abbreviation for central processing unit. "GPU" is an abbreviation for graphics processing unit. "RAM" is an abbreviation for random access memory. "ROM" is an abbreviation for read-only memory. The functions of the controller 32 are realized by the processor executing a program loaded into memory. In other words, the functions of the controller 32 are realized by software. Alternatively, the controller 32 may have a programmable circuit such as an FPGA or a dedicated circuit such as an ASIC instead of or in addition to the processor. "FPGA" is an abbreviation for field-programmable gate array. "ASIC" is an abbreviation for application specific integrated circuit. Some or all of the functions of the controller 32 may be implemented by programmable circuits or dedicated circuits. That is, some or all of the functions of the controller 32 may be implemented by hardware circuits. The controller 32 may further have a communication module for communicating with the infusion probe 31 by wire or wireless. Alternatively, the controller 32 may share the communication module of the infusion pump 15 for communicating with the infusion probe 31.

[0035] Next, the configuration of the intravenous infusion probe 31 according to this embodiment will be described with reference to Figure 2. Figure 2 is a horizontal cross-sectional view showing the configuration of the intravenous infusion probe 31 according to this embodiment.

[0036] The infusion probe 31 is attached to the drip chamber 20. The infusion probe 31 includes an illumination unit 33 that emits light toward the drip chamber 20, and an imaging unit 34 that is positioned opposite the illumination unit 33 across the drip chamber 20.

[0037] The illumination unit 33 includes a light source 41 and a second photoconverter 51. The light source 41 is, for example, a near-infrared LED. "LED" is an abbreviation for light-emitting diode. The second photoconverter 51 is, for example, an aspherical lens with the shape shown in Figure 3. In this embodiment, the illumination unit 33 further includes an optical element 42 disposed between the light source 41 and the second photoconverter 51. The optical element 42 is, for example, an aspherical lens or a Fresnel lens.

[0038] The imaging unit 34 includes a first optical transducer 52, a light-gathering element 43, and a camera 44. The first optical transducer 52 is, for example, an aspherical lens with the shape shown in Figure 3. The light-gathering element 43 is, for example, an aspherical lens or a Fresnel lens. The camera 44 takes pictures of the inside of the drip chamber 20 using light from the illumination unit 33. The camera 44 is, for example, a near-infrared camera. The camera 44 includes an image sensor and a light-gathering element that collects light on the image sensor. As the image sensor of the camera 44, for example, a CMOS or CCD is used. "CMOS" is an abbreviation for complementary metal-oxide-semiconductor. "CCD" is an abbreviation for charge-coupled device. As the light-gathering element of the camera 44, for example, a lens or a pinhole is used. Figure 2 shows a configuration for detecting liquid droplets in which the imaging unit 34 includes only a camera 44; however, the imaging unit 34 may further include a sensor (not shown). The sensor (not shown) detects when light from the light source 41 is blocked, as this indicates that a liquid droplet has fallen into the drip chamber 20. The sensor is installed, for example, above or below the camera 44.

[0039] The illumination unit 33 emits multiple first light components. Specifically, the second optical converter 51 of the illumination unit 33 converts the optical paths of multiple light components contained in the light irradiated by the light source 41 and emits multiple first light components. More specifically, the second optical converter 51 emits multiple light components that travel non-parallel to each other before incident on the drip chamber 20, are refracted at least partially when incident on the drip chamber 20, and travel parallel to each other inside the drip chamber 20 after incident on the drip chamber 20. As a method for implementing a second optical converter 51 capable of emitting such light components, for example, one could design an optimal aspherical lens by performing optical simulations using parameters such as the refractive index of the material of the drip chamber wall and the curvature of the drip chamber wall.

[0040] In this embodiment, the optical element 42 emits light irradiated by the light source 41 as parallel light. As shown in Figure 3, the second optical converter 51 converts the optical paths 50A of multiple light components contained in the parallel light emitted from the optical element 42 to emit multiple first light components. The optical paths 50B of the multiple first light components emitted from the second optical converter 51 before incidence into the drip chamber 20 are non-parallel to each other. At least a portion of the multiple first light components are refracted by the first portion 21 of the drip chamber wall when incident into the drip chamber 20. As a result, the optical paths 50C of the multiple first light components after incidence into the drip chamber 20 become parallel to each other.

[0041] The first optical converter 52 of the imaging unit 34 converts the optical paths of multiple second optical components, which are among a plurality of first optical components emitted from the illumination unit 33, are incident on the drip chamber 20, travel parallel to each other inside the drip chamber 20, are emitted from the drip chamber 20, and are at least partially refracted when they are emitted from the drip chamber 20, thereby emitting parallel light. As a method for implementing such a first optical converter 52, for example, similar to the method for implementing the second optical converter 51, it is conceivable to design an optimal aspherical lens by performing optical simulations using parameters such as the refractive index of the material of the drip chamber wall and the curvature of the drip chamber wall.

[0042] In this embodiment, a plurality of first light components emitted from the second optical converter 51 enter the drip chamber 20, travel parallel to each other inside the drip chamber 20, and are then emitted from the drip chamber 20. At least a part of the plurality of first light components are refracted at the second part 22 of the drip chamber wall when being emitted from the drip chamber 20. As a result, as shown in FIG. 3, the optical paths 50D of the plurality of first light components after being emitted from the drip chamber 20 become non-parallel to each other. The plurality of first light components enter the first optical converter 52 as a plurality of second light components after being emitted from the drip chamber 20, are converted into parallel light components, and then are emitted. As a result, the optical paths 50E of the plurality of second light components after being emitted from the first optical converter 52 become parallel to each other.

[0043] The condensing element 43 condenses the parallel light emitted from the first optical converter 52. The image sensor of the camera 44 converts the light emitted from the condensing element 43 into an image 70 as shown in FIG. 4.

[0044] The controller 32 acquires the image 70 from the drip probe 31. The controller 32 estimates the volume of the falling droplets 80 included in the image 70. The controller 32 calculates the flow rate of the drip chamber 20 based on the obtained estimation result. As a method for estimating the volume of the falling droplets 80 and a method for calculating the flow rate of the drip chamber 20, known methods can be used.

[0045] As described above, in this embodiment, the drip probe 31 attached to the drip chamber 20 includes an illumination unit 33 that irradiates the drip chamber 20 with light containing at least first light that becomes parallel light inside the drip chamber 20, and an imaging unit 34 that faces the illumination unit 33 and captures an image 70 of the drip chamber 20. The imaging unit 34 includes a first optical converter 52 that optically converts the first light refracted at the wall surface facing the imaging unit 34 of the drip chamber 20 into parallel light, a condensing element 43 that condenses the first light converted into parallel light by the first optical converter 52, and a camera 44 that receives the first light condensed by the condensing element 43.

[0046] According to this embodiment, while adopting a parallel optical system in the drip probe 31, it is possible to cope with the refraction generated at the drip chamber wall, so that the accuracy of imaging the droplets in the drip chamber 20 is improved.

[0047] By adopting a collimated light optical system, if the liquid is opaque, the light rays will be blocked by the liquid, and if the liquid is transparent, the traveling direction of the light rays will change due to refraction within the liquid except at the center. In either case, a shadow image can be obtained.

[0048] Also, in the configuration adopting the collimated light optical system, even if the droplet dropping position changes front, back, left, or right, the size of the imaged droplet does not change. That is, even if the droplet dropping position becomes far, near, shifted to the left, or shifted to the right, the size of the shadow of the droplet does not change. As a result, even if there are droplets adhering to the wall surface on the camera 44 side of the drip cylinder 20, it is possible to prevent the adhered droplets from being photographed with a large size. Therefore, the camera 44 can reduce the influence of the droplets adhering to the wall surface and photograph the droplets dropping near the center of the drip cylinder 20.

[0049] As a result, the drip probe 31 can accurately image the peripheral portion of the wall surface of the drip cylinder 20, and can also image the shadow of the droplet with the same size regardless of the droplet dropping position.

[0050] In the present embodiment, the illumination unit 33 includes a second light converter 51 that converts the optical path so that the parallel illumination light becomes collimated light within the drip cylinder 20. The first light converter 52 converts the optical path so that the light passing through the drip cylinder 20 returns to collimated light again. As a result, the parallel illumination light reaches the camera 44 without leakage as collimated light.

[0051] Hereinafter, a second embodiment, which is another embodiment of the present disclosure, will be described.

[0052] The configuration of the infusion system 10 according to the present embodiment is the same as that of the first embodiment, so the description will be omitted. The configuration of the measuring device 30 according to the present embodiment is also the same as that of the first embodiment, so the description will be omitted.

[0053] Referring to FIG. 5, the configuration of the drip probe 31 according to the present embodiment will be described. The description of the same points as those in the first embodiment may be omitted.

[0054] The infusion probe 31, as in the first embodiment, includes an illumination unit 33 and an imaging unit 34 positioned opposite the illumination unit 33 with the infusion chamber 20 in between.

[0055] The illumination unit 33 includes a light source 41 and a second photoconverter 51A. The light source 41 is, for example, a near-infrared LED. The second photoconverter 51A is, for example, a diffuser plate. In this embodiment, unlike the first embodiment, the illumination unit 33 does not include an optical element 42 as shown in Figure 2.

[0056] The imaging unit 34 includes a first optical transducer 52, a light-gathering element 43, and a camera 44. The first optical transducer 52 is, for example, an aspherical lens with the shape shown in Figure 6. The light-gathering element 43 is, for example, an aspherical lens or a Fresnel lens. The camera 44 includes an image sensor and a light-gathering element that collects light on the image sensor. For example, a CMOS or CCD is used as the image sensor of the camera 44. For example, a lens or a pinhole is used as the light-gathering element of the camera 44.

[0057] The illumination unit 33 emits multiple first light components. Specifically, the second photoconverter 51A of the illumination unit 33 converts the optical paths of multiple light components contained in the light irradiated by the light source 41 and emits multiple first light components. More specifically, unlike the second photoconverter 51 in the first embodiment, the second photoconverter 51A diffuses the light irradiated by the light source 41 and emits diffused light containing multiple first light components.

[0058] In this embodiment, a plurality of second light components, which are part of a plurality of first light components emitted from the second optical converter 51A, are incident on the drip chamber 20. As shown in Figure 6, the optical paths 50B of the plurality of second light components before incidence on the drip chamber 20 are non-parallel to each other. At least a portion of the plurality of second light components are refracted by the first portion 21 of the drip chamber wall when incident on the drip chamber 20. As a result, the optical paths 50C of the plurality of second light components after incidence on the drip chamber 20 become parallel to each other.

[0059] The first optical converter 52 of the imaging unit 34 converts the optical paths of multiple second optical components, which are among a plurality of first optical components emitted from the illumination unit 33, are incident on the drip chamber 20, travel parallel to each other inside the drip chamber 20, are emitted from the drip chamber 20, and are at least partially refracted when they are emitted from the drip chamber 20, thereby emitting parallel light. As a method for implementing such a first optical converter 52, for example, one could design an optimal aspherical lens by performing an optical simulation using parameters such as the refractive index of the material of the drip chamber wall and the curvature of the drip chamber wall.

[0060] In this embodiment, of the multiple first light components emitted from the second optical converter 51A, multiple second light components are incident on the drip chamber 20, travel parallel to each other inside the drip chamber 20, and are emitted from the drip chamber 20. At least a portion of the multiple second light components are refracted by the second portion 22 of the drip chamber wall when they are emitted from the drip chamber 20. As a result, as shown in Figure 6, the optical paths 50D of the multiple second light components after they are emitted from the drip chamber 20 become non-parallel to each other. After being emitted from the drip chamber 20, the multiple second light components are incident on the first optical converter 52, converted into parallel light components, and emitted. As a result, the optical paths 50E of the multiple second light components after they are emitted from the first optical converter 52 become parallel to each other.

[0061] Similar to the first embodiment, the light-gathering element 43 focuses the parallel light emitted from the first optical converter 52. Similar to the first embodiment, the image sensor of the camera 44 converts the light emitted from the light-gathering element 43 into an image 70 as shown in Figure 4.

[0062] According to this embodiment, as with the first embodiment, it is possible to address refraction occurring in the drip chamber wall, thereby improving the accuracy of imaging droplets inside the drip chamber 20. Specifically, it becomes possible to accurately image the peripheral area of ​​the wall surface of the drip chamber 20. It also becomes possible to image the shadow of the droplet at the same size regardless of the droplet's landing position.

[0063] In this embodiment, the illumination unit 33 includes a second photoconverter 51A that diffuses the illumination light. The diffused light always contains light components that become parallel light within the drip chamber 20. The first photoconverter 52 converts the optical path so that such light components, having passed through the drip chamber 20, return to parallel light. The light-gathering element 43 focuses only the light components incident in parallel onto the camera 44. As a result, a portion of the diffused light reaches the camera 44 as parallel light.

[0064] Referring to Figure 7, an example in which a pinhole 53 is applied to the infusion probe 31 according to this embodiment will be described.

[0065] In this example, the camera 44 includes an image sensor 45 and a pinhole 53 positioned between the light-gathering element 43 and the image sensor 45, at a position corresponding to the focal point of the light-gathering element 43. The diameter of the pinhole 53 is preferably 0.5 mm or less.

[0066] In this example, only the parallel light component of the subject area, including the falling droplet 80 in the drip chamber 20, is focused at the focal point of the light-gathering element 43, passes through the pinhole 53, and is projected onto the image sensor 45 as a shadow image 71. As a result, the parallel light selectivity of the imaging unit 34 is improved, making it easier to image only the parallel light component in the drip chamber 20.

[0067] Referring to Figure 8, an example in which a small-diameter lens 54 is applied to the intravenous probe 31 according to this embodiment will be described.

[0068] In this example, the camera 44 includes a lens 54 positioned between the light-gathering element 43 and the image sensor 45, at a position corresponding to the focal point of the light-gathering element 43, instead of a pinhole 53. The diameter of the lens 54 is preferably 2.0 mm or less.

[0069] In this example as well, only the parallel light component of the subject area, including the falling droplet 80 in the drip chamber 20, is focused at the focal point of the light-gathering element 43, passes through the lens 54, and is projected onto the image sensor 45 as a shadow image 71. As a result, the parallel light selectivity of the imaging unit 34 is improved, making it easier to image only the parallel light component inside the drip chamber 20.

[0070] A pinhole 53 as shown in Figure 7, or a small-diameter lens 54 as shown in Figure 8, may be applied to the drip probe 31 according to the first embodiment.

[0071] As one modification of this embodiment, the lighting unit 33 may include a light source 41 that emits diffuse light containing multiple first light components, instead of including a second photoconverter 51A. The light source 41 may be, for example, multiple LEDs or an organic EL. "EL" is an abbreviation for electroluminescent.

[0072] This disclosure is not limited to the embodiments described above. Further modifications are possible without departing from the spirit of this disclosure.

[0073] 10 Infusion system 11 Infusion container 12 Connector 13 Infusion tube 14 Clamp 15 Infusion pump 20 Drip chamber 21 First part 22 Second part 30 Measuring device 31, 31A Drip probe 32 Controller 33 Illumination unit 34 Imaging unit 41 Light source 42 Optical element 43 Light-gathering element 44 Camera 45 Image sensor 50A, 50B, 50C, 50D, 50E Optical path 51, 51A Second optical transducer 52 First optical transducer 53 Pinhole 54 Lens 70 Image 71 Shadow image 80, 80A, 80B Falling droplet

Claims

1. An intravenous drip probe to be attached to a drip chamber, comprising: an illumination unit that emits a plurality of first light components; a first optical converter provided at a position opposite the illumination unit across the drip chamber, which converts the optical paths of a plurality of second light components that are incident on the drip chamber from the plurality of first light components emitted from the illumination unit, travel parallel to each other inside the drip chamber, are emitted from the drip chamber, and are at least partially refracted when emitted from the drip chamber, thereby emitting parallel light; a focusing element that focuses the parallel light emitted from the first optical converter; and an imaging unit including an image sensor that converts the light emitted from the focusing element into an image.

2. The intravenous drip probe according to claim 1, wherein the first optical converter is an aspherical lens.

3. The drip probe according to claim 1, wherein the illumination unit includes a light source and a second photoconverter that converts the optical paths of a plurality of light components contained in the light irradiated by the light source and emits the plurality of first light components.

4. The drip probe according to claim 3, wherein the second optical converter emits a plurality of light components as the plurality of first light components, which travel non-parallel to each other before incidence into the drip chamber, are refracted at least partially upon incidence into the drip chamber, and travel parallel to each other inside the drip chamber after incidence into the drip chamber.

5. The drip probe according to claim 4, wherein the illumination unit further includes an optical element disposed between the light source and the second photoconverter, which emits the light irradiated by the light source as parallel light, and the second photoconverter converts the optical paths of a plurality of light components contained in the parallel light emitted from the optical element to emit the plurality of first light components.

6. The infusion probe according to claim 3, wherein the second photoconverter diffuses the light irradiated by the light source and emits diffused light containing the plurality of first light components.

7. The drip probe according to claim 1, wherein the illumination unit includes a light source that emits diffuse light containing the plurality of first light components.

8. The intravenous drip probe according to claim 1, wherein the imaging unit further includes a pinhole positioned between the light-gathering element and the image sensor at a position corresponding to the focal point of the light-gathering element.

9. The intravenous drip probe according to claim 1, wherein the imaging unit further includes a lens positioned between the light-gathering element and the image sensor at a position corresponding to the focal point of the light-gathering element.

10. A measuring device comprising: an intravenous drip probe according to any one of claims 1 to 9; and a controller that acquires an image from the intravenous drip probe, estimates the volume of the falling droplets contained in the image, and calculates the flow rate of the drip chamber based on the obtained estimation result.

Images