Spectrometer and article inspection device including the same

Abstract

To provide a spectrometer that can prevent entry of stray light to an optical fiber, and can prevent a reduction in the accuracy of data of the spectrum of light incident on the optical fiber, and an article inspection device.SOLUTION: A spectrometer comprises: a light source unit 3 that irradiates a tablet W with light; and a light detection unit 4 including an optical fiber 41 on which transmitted light is incident that is light emitted from the light source unit 3 and having transmitted through the tablet W, and a spectroscope 42 that measures the spectral characteristics of the transmitted light having transmitted through the optical fiber 41. The light detection unit 4 further has a cylindrical member 45 between the tablet W and the optical fiber 41. An opening 45a at an end on the side of the tablet W of the cylindrical member 45 is located closer to the side of the tablet W than an incident end 41a of the optical fiber 41. The transmitted light is transmitted through the cylindrical member 45 from the opening 45a and is incident on the optical fiber 41.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a spectroscopic measurement device and an article inspection device. [Background technology]

[0002] Patent Document 1 discloses a technology in which light is irradiated onto an object from a light source, the light that passes through the object is received by a detection unit, and the spectral data of the light received by the detection unit is detected as measurement data. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 135233 Summary of the Invention [Problem to be solved by the invention]

[0004] However, although the technology described in Patent Document 1 is equipped with a lens that focuses light that has passed through the object, no measures are taken to prevent light other than that which has passed through the object from entering the detection unit.

[0005] Therefore, in the technology described in Patent Document 1, there is a risk that light other than the light irradiated from the light source and transmitted through the object may be received by the detection unit as stray light, which may reduce the accuracy of the spectral data of the light received by the detection unit.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a spectroscopic measurement device and an article inspection device that can prevent stray light from entering an optical fiber and prevent a decrease in the accuracy of the spectral data of light incident on the optical fiber. [Means for solving the problem]

[0007] The spectroscopic measurement device of the present invention comprises a light source unit that irradiates light onto an object, an optical fiber into which transmitted light irradiated from the light source unit and transmitted through the object is incident, and a light detection unit that includes a spectrometer that measures the spectral characteristics of the transmitted light that has passed through the optical fiber, wherein the light detection unit further has a tubular member between the object and the optical fiber, and an opening at the end of the tubular member facing the object is located closer to the object than the incident end of the optical fiber, and the transmitted light passes through the tubular member from the opening and is incident on the optical fiber.

[0008] With this configuration, the spectroscopic measurement device according to the present invention is configured such that the light detection unit has a tubular member between the object and the optical fiber, the opening at the end of the tubular member facing the object is located closer to the object than the incident end of the optical fiber, and the transmitted light passes through the tubular member from the opening and enters the optical fiber. Therefore, the tubular member can block light other than the transmitted light that is irradiated from the light source unit and transmitted through the object from entering the incident end of the optical fiber. Therefore, the spectroscopic measurement device according to the present invention can prevent stray light from entering the optical fiber and prevent a decrease in the accuracy of the spectral data of the light that enters the optical fiber.

[0009] In the spectroscopic measurement device according to the present invention, it is preferable that the inner wall surface of the cylindrical member is subjected to a light-absorbing surface treatment.

[0010] With this configuration, the spectroscopic measurement device according to the present invention has the inner wall surface of the cylindrical member subjected to a light-absorbing surface treatment, so that even if stray light enters the cylindrical member through the gap between the object and the cylindrical member and through the opening of the cylindrical member, the stray light can be absorbed or attenuated by the inner wall surface, thereby reducing the stray light incident on the input end of the optical fiber.

[0011] In the spectroscopic measurement device according to the present invention, it is preferable that the cylindrical member has an open end where the opening is formed, and the open end is formed sharply.

[0012] With this configuration, the spectroscopic measuring device of the present invention has a sharply formed opening end of the tubular member, which prevents stray light from being reflected toward the object at the opening end of the tubular member facing the object and then from the object toward the incident end of the optical fiber.

[0013] In the spectroscopic measurement device according to the present invention, it is preferable that the light source unit is configured to irradiate light onto the object while it is moving, and that the opening of the cylindrical member has an elliptical shape with a minor axis that is shorter than the diameter of the object in the direction of movement of the object.

[0014] With this configuration, in the spectroscopic measurement device according to the present invention, the shape of the opening of the cylindrical member is elliptical with a minor axis that is shorter than the diameter of the object in the direction of movement of the object, so that the time during which the moving object and the opening of the cylindrical member overlap in the axial direction can be extended, thereby enabling light to be irradiated onto the moving object for a longer period of time, thereby improving the accuracy of the data on the spectrum of light incident on the optical fiber.

[0015] In the spectroscopic measurement device according to the present invention, it is preferable that the cylindrical member is configured to be replaceable depending on the type of the article.

[0016] With this configuration, the spectroscopic measurement device according to the present invention is configured so that the cylindrical member is replaceable depending on the type of article, and so when the object to be measured is changed to a different type of article, the cylindrical member can be changed to one with an opening dimension and axial length that is optimal for the new object depending on, for example, the shape, dimensions, etc. of the new object. This makes it possible to prevent stray light from entering the optical fiber even when the object to be measured is changed.

[0017] An article inspection device according to the present invention includes the spectroscopic measurement device according to claim 1 or 2, and an inspection unit that inspects the quality of the article based on the spectroscopic characteristics measured by the spectroscope.

[0018] With this configuration, the item inspection device of the present invention is equipped with a spectroscopic measuring device that can prevent stray light from entering the optical fiber and prevent a decrease in the accuracy of the spectral data of light incident on the optical fiber, thereby preventing a decrease in the inspection accuracy of the item quality by the inspection unit. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a spectroscopic measurement device and an article inspection device that can prevent stray light from entering an optical fiber and prevent a decrease in the accuracy of the spectral data of light incident on the optical fiber. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic diagram of an article inspection device equipped with a spectroscopic measurement device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing a spectroscopic measurement device of a comparative example that does not include a cylindrical member of the spectroscopic measurement device according to one embodiment of the present invention. [Figure 3] FIG. 3 is a schematic diagram illustrating the operation of the spectroscopic measurement device according to one embodiment of the present invention. [Figure 4] FIG. 4 is a graph illustrating the operation of a spectroscopic measurement device according to one embodiment of the present invention, showing the relationship between the distance between the article and the incident end of the optical fiber and the coefficient of variation. [Figure 5] FIG. 5 is a diagram showing an example of a cylindrical member having a cross section perpendicular to the axial direction in a perfect circular shape in a spectroscopic measurement device according to one embodiment of the present invention. [Figure 6] FIG. 6 is a diagram showing an example of a tubular member having an elliptical cross section perpendicular to the axial direction in a spectroscopic measurement device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an article inspection device equipped with a spectroscopic measurement device according to one embodiment of the present invention will be described with reference to the drawings.

[0022] In this embodiment, when an item to be inspected is transported individually along a transport path by a transport unit and reaches a predetermined inspection position, the item inspection device irradiates light onto the item, which is in a fixed position at the predetermined inspection position, and inspects the quality of the item based on the spectral characteristics of the transmitted light that passes through the item upon irradiation with this light (also called irradiated light).

[0023] The items to be inspected are items that are relatively close in size to the area irradiated with light, and include items with an outer diameter φ of several mm to several tens of mm that can be transported individually without packaging, bite-sized items, as well as items and molded products of a predetermined shape manufactured using existing manufacturing equipment or manufacturing equipment without inspection functions, and especially items that do not change shape during transportation.

[0024] Examples of such articles include pharmaceutical preparations such as tablets, capsules, lozenges, and drops, as well as candy and chocolate. The following description will be given taking as an example an article to be inspected a tablet W that is circular in plan view, has a height (thickness) smaller than its diameter, and is roughly cylindrical in side view. Note that the article to be inspected is not limited to a circular shape in plan view, and articles of various shapes such as an oval shape or a polygonal shape can also be used.

[0025] The conveying unit may be, for example, a conveying unit configured to align and convey articles individually, such as a conveying belt, a conveying disk, or a conveying chute. In this embodiment, an example will be described in which a conveying disk 11 (see FIG. 1) is used as the conveying unit.

[0026] As shown in Fig. 1, the conveying disk 11 is a conveying unit configured to suck tablets W into suction holes on its outer peripheral surface and convey them in the circumferential direction while rotating horizontally. In the conveying disk 11, the tablets W are conveyed with their upper and lower surfaces kept horizontal as their sides are sucked into the suction holes. In Fig. 1, only a portion of the outer peripheral side of the conveying disk 11 is shown.

[0027] The article inspection device 10 according to this embodiment includes a spectroscopic measurement device 1 and an inspection unit 2.

[0028] [Spectrometry device] The spectroscopic measurement device 1 includes a light source unit 3 and a light detection unit 4. The spectroscopic measurement device 1 irradiates a tablet W to be measured with broadband light (visible light, near-infrared to terahertz light (terahertz waves)), and measures the spectral characteristics of the light that passes through the tablet W in response to the irradiation of this light.

[0029] (Light source part) The light source unit 3 is configured to irradiate broadband light onto the tablet W passing through a predetermined inspection position, i.e., onto the tablet W being conveyed (moving). In this embodiment, the light source unit 3 is arranged on the opposite side (lower side in this embodiment) from the light detection unit 4 across the conveyance path of the tablet W so as to irradiate light from one side (lower side in this embodiment) of a pair of circular end faces of the approximately cylindrical tablet W to the other side (upper side in this embodiment).

[0030] The conveying path of the tablet W is an area through which the tablet W passes during conveyance. The predetermined inspection position is a position on the conveying path of the tablet W where the light source unit 3 and the light detection unit 4 are arranged.

[0031] The light source unit 3 includes a light source 30 , a light guide 31 , and an optical lens 32 .

[0032] The light source 30 is composed of a broadband light source, such as a halogen lamp, in order to irradiate broadband light onto the tablet W to be measured, and is provided at a predetermined position as a light source unit integrally assembled with a lamp holding means (not shown) and a case having heat dissipation fins, and is connected to a power supply unit (neither of which is shown).

[0033] Broadband light refers to light that includes visible light, near-infrared light, and terahertz light (terahertz waves). The wavelength of the irradiated light does not need to cover all of these; for example, a wavelength band of 400-2500 nm can easily pass through a measured object such as a tablet and is less likely to cause damage from ultraviolet rays, so the light may be limited to this wavelength band or the near-infrared band within this wavelength band. Furthermore, if the absorption spectrum of the component to be measured is known, only the wavelength band corresponding to the absorption spectrum may be used.

[0034] The light guide 31 is made up of a number of glass optical fibers bundled together, and guides the light from the light source 30 to an optical lens 32 that condenses the light.

[0035] The optical lens 32 focuses the light from the light guide 31 onto the tablet W at a predetermined inspection position (the lower surface of the tablet W in the example of FIG. 1).

[0036] The light source unit 3 emits broadband light from the light source 30 to the optical lens 32 via the light guide 31, and adjusts the magnification of the optical lens 32 (the positions of the optical lens 32, light source 30 and tablet W) so that the optical lens 32 covers the entire underside of the tablet W at the specified inspection position, thereby efficiently irradiating the light from the light source 30 onto the tablet W passing through the specified inspection position.

[0037] (Photodetector) The light detecting section 4 has an optical fiber 41 and a spectroscope 42. The light detecting section 4 is formed as a unit by supporting the optical fiber 41 and the spectroscope 42 on a base member 40.

[0038] The light detection unit 4 is positioned on the opposite side (in this embodiment, the upper side) from the light source unit 3 across the conveying path of the tablet W, so as to face the other (in this embodiment, the upper side) of a pair of circular end faces of the approximately cylindrical tablet W.

[0039] The optical fiber 41 is configured so that transmitted light that has passed through the tablet W at a predetermined inspection position is incident on its core portion 41b. The transmitted light that has passed through the tablet W enters the optical fiber 41 from an end face (hereinafter referred to as the "incident end") 41a of the incident surface of the optical fiber 41. The transmitted light that has entered the optical fiber 41 passes through the optical fiber 41 and reaches the spectroscope 42.

[0040] The spectroscope 42 performs spectrometry using, for example, a grating that utilizes differences in the diffraction angle depending on the wavelength of light. Specifically, the light that enters the spectroscope 42 is irradiated onto a grating (diffraction grating) and separated into individual wavelength components. The light separated into individual wavelength components is then detected for each wavelength component by a row of photodetector elements. The light intensity for each wavelength component is then measured. The grating is an optical element with multiple grooves engraved on its surface.

[0041] A tapered optical fiber with a large input diameter and a small output diameter can be used as the optical fiber 41. This allows the transmitted light to be incident on the spectroscope 42 more efficiently.

[0042] In this way, the light detection unit 4 receives light irradiated from the light source unit 3 and transmitted through the tablet W, and the transmitted light is incident on the optical fiber 41, and the spectrometer 42 measures the spectral characteristics of the transmitted light that has passed through the optical fiber 41.

[0043] In this embodiment, the light detection unit 4 is provided with a reflective cover 43. The reflective cover 43 is provided so as to surround the incident end 41a of the optical fiber 41, and has a hemispherical shape that widens from the incident end 41a of the optical fiber 41 toward the upper surface of the tablet W. The shape of the inner surface of the reflective cover 43 is not limited to a hemispherical shape, and may be, for example, a truncated cone shape.

[0044] The reflective cover 43 has a reflective surface 43a on the inner surface of the hemisphere that reflects the transmitted light that has passed through the tablet W onto the upper surface of the tablet W. In addition, the incident end 41a of the optical fiber 41 is disposed near the apex of the hemisphere.

[0045] The transmitted light irradiated from the light source unit 3 and transmitted through the tablet W is repeatedly reflected between the reflecting surface 43a of the reflecting cover 43 and the upper surface of the tablet W, so that part of the light that would not have been able to reach the incident end 41a of the optical fiber 41 without the reflecting cover 43 reaches the incident end 41a. In this way, the reflecting cover 43 can increase the amount of transmitted light incident on the incident end 41a of the optical fiber 41.

[0046] In this embodiment, the light detection unit 4 has a cylindrical member 45 between the tablet W and the optical fiber 41 at a predetermined inspection position. The cylindrical member 45 is detachably attached to the base member 40, protrudes from the base member 40 toward the tablet W, and is open on the tablet W side. The cylindrical member 45 may be made of metal such as aluminum, or may be made of resin, for example.

[0047] Specifically, the cylindrical member 45 is formed in a cylindrical shape having a predetermined length in the protruding direction (vertical direction in this embodiment), and has an opening end 45b where an opening 45a is formed at the end on the tablet W side (lower side in this embodiment) in the protruding direction. In this embodiment, the shape of the opening 45a is formed in a perfect circle.

[0048] The end of the cylindrical member 45 opposite to the tablet W side in the protruding direction (the upper side in this embodiment) is also open, but the diameter of the opening does not have to be the same as the diameter of the opening 45a. It is sufficient that an opening large enough to pass at least the optical fiber 41 is formed in the end of the cylindrical member 45 opposite to the tablet W side in the protruding direction.

[0049] The cylindrical member 45 is arranged so that the incident end 41a of the optical fiber 41 and the opening 45a overlap in the axial direction of the cylindrical member 45 (vertical direction in FIG. 1). In other words, when the light detection unit 4 is viewed from the tablet W side in the axial direction of the cylindrical member 45, the incident end 41a of the optical fiber 41 is contained within the opening area of ​​the opening 45a. This arrangement is preferably such that the center of the incident end 41a of the optical fiber 41 is positioned on the axial line of the cylindrical member 45 that passes through the center of the opening 45a. The transmitted light that has passed through the tablet W passes through the cylindrical member 45 from the opening 45a and enters the optical fiber 41.

[0050] Furthermore, the opening 45a of the cylindrical member 45 is located closer to the tablet W than the incident end 41a of the optical fiber 41. In other words, the incident end 41a of the optical fiber 41 is farther away from the tablet W in the axial direction of the cylindrical member 45 than the opening 45a of the cylindrical member 45. In this embodiment, the incident end 41a of the optical fiber 41 is arranged so as to be located inside the cylindrical member 45.

[0051] The incident end 41a of the optical fiber 41 may be disposed, for example, so as to be located inside the base member 40. Furthermore, the optical fiber 41 may be configured so that the position of the incident end 41a in the axial direction of the cylindrical member 45 is adjustable.

[0052] The cylindrical member 45 has an inner wall surface 45c that is subjected to a low-reflectivity surface treatment for absorbing light, such as painting the inner wall surface 45c black to suppress light reflection.

[0053] In this embodiment, the opening end 45b of the cylindrical member 45 is formed to be sharp. That is, the opening end 45b of the cylindrical member 45 has a tapered shape, and the area of ​​the surface facing the tablet W at the opening end 45b is reduced.

[0054] Furthermore, the cylindrical member 45 has an outer wall surface 45d formed in a tapered shape that increases in diameter from the opening end 45b toward the base member 40. This increases the rigidity of the cylindrical member 45 when the cylindrical member 45 is attached to the base member 40. Note that the outer wall surface 45d of the cylindrical member 45 does not have to be tapered. The outer wall surface 45d may be subjected to a low-reflectivity surface treatment that absorbs light.

[0055] The tapered shape of the open end 45b may be, for example, a shape that gradually tapers in accordance with the tapered shape of the outer wall surface 45d, or only the end of the tubular member 45 on the open end 45b side may be tapered.

[0056] [Inspection Department] The inspection unit 2 has a signal processing unit 2a that processes the spectroscopic characteristics obtained by the light detection unit 4 within a predetermined exposure time, and inspects the quality of the tablet W, i.e., determines whether the quality of the tablet W is good or bad, based on the results of the signal processing.

[0057] The signal processing unit 2a calculates the spectral characteristics of the absorbance absorbed by the tablet W from the spectral characteristics obtained by the light detection unit 4. Specifically, the absorbance A at wavelength λ is obtained by the formula A=-log10(I / Ii), which is the common logarithm of the ratio (transmittance) of the light intensity Ii of the incident light to the light intensity I of the transmitted light, and the transmitted amount detected when there is no tablet W at the predetermined inspection position can be calculated as the light intensity Ii of the incident light.

[0058] The inspection unit 2 compares the spectroscopic characteristics of absorbance of a non-defective tablet W obtained in advance (intensity of each wavelength of the spectrum (including when differentiated multiple times), waveform shape, information obtained by extracting the entire or partial region and creating a calibration curve, statistical information) with the spectroscopic characteristics of absorbance of the tablet W to be inspected that has been transported to a predetermined inspection position, and judges whether the quality of the tablet W is good or bad based on the magnitude of the difference. The inspection unit 2 outputs a sorting signal based on the pass / fail result of the judgment to a sorting unit (not shown) that sorts the tablets W into normal and defective products.

[0059] Specifically, for example, the quality of the tablet W is judged based on whether the difference amount for each wavelength determined by calculation using a calibration curve obtained by statistical calculation results (such as standard deviation) or statistical methods such as regression is within a predetermined range (a range determined based on the results of statistical calculations or the results of the calibration curve).The quality of the tablet W can also be judged based on whether the sum of the intensities of each wavelength is within a predetermined range.Furthermore, if the components of the tablet W are uniform, the quality of the tablet W may be judged based on whether there is an intensity exceeding a predetermined threshold value set in advance in a region other than the specific wavelength.

[0060] [About the function of the cylindrical member] Next, the operation of the cylindrical member 45 of this embodiment will be described with reference to FIGS.

[0061] 2 and 3 schematically show how a plurality of tablets W are sequentially conveyed at predetermined intervals in the conveying direction and irradiated at a predetermined inspection position with light from the light source unit 3. The solid arrows and dashed arrows in Fig. 2 and 3 schematically show the optical paths of part of the light irradiated from the light source unit 3 or the reflected light.

[0062] Fig. 2 shows a spectroscopic measurement device 101 of a comparative example that does not include a cylindrical member 45. The spectroscopic measurement device 101 of the comparative example differs from the spectroscopic measurement device 1 of the present embodiment in that it does not include a cylindrical member 45, but other configurations are the same as those of the spectroscopic measurement device 1 of the present embodiment. Fig. 3 shows the spectroscopic measurement device 1 of the present embodiment.

[0063] 2, in the spectroscopic measurement device 101 of the comparative example, most of the light irradiated from the light source unit 3 is incident on the tablet W, while some of the light is reflected by the side surfaces of the tablets W (previously transported tablet, next transported tablet) arranged at a predetermined interval relative to the tablet W being measured, and then enters the reflective cover 43. The light that has entered this reflective cover 43 is further reflected within the reflective cover 43 and reflected by the upper surface of the tablet W, and then enters the incident end 41 a of the optical fiber 41.

[0064] In this way, the light reflected by the tablets W transported before and after the tablet W under measurement and incident on the incident end 41a of the optical fiber 41 is incident as stray light on the optical fiber 41. In this case, there is a risk that the accuracy of the data on the spectrum of the light received by the light detection unit 4 will decrease.

[0065] In contrast, as shown in FIG. 3, in the spectroscopic measurement device 1 of this embodiment, most of the light irradiated from the light source unit 3 is incident on the tablet W, but is also reflected from the sides of the tablets W (previously transported tablets, next transported tablets) that are lined up at a predetermined interval relative to the tablet W being measured. However, the reflected light is blocked by the outer wall surface 45d of the cylindrical member 45, and the amount of light incident on the reflective cover 43 is reduced.

[0066] Furthermore, part of the light reflected by the side surfaces of the tablets W arranged at predetermined intervals relative to the tablet W being measured is also reflected by the lower surface of the base member 40. Here, if the lower surface of the base member 40 is close to the opening end 45b of the cylindrical member 45, there is a possibility that the light reflected by the lower surface of the base member 40 will be reflected again by the upper surface of at least one of the tablets W being transported previously and the tablets W being transported next, and enter the cylindrical member 45.

[0067] In this embodiment, the lower surface of the base member 40 is farther from the tablets W than the open end 45b of the cylindrical member 45, so the optical path of the light reflected at the lower surface of the base member 40 becomes longer, and the light is attenuated before being reflected again at the upper surface of at least one of the previously transported and next transported tablets W and entering the cylindrical member 45. Therefore, the possibility that the light reflected at the lower surface of the base member 40 will enter the cylindrical member 45 can be reduced.

[0068] Note that light that may be incident as stray light on the incident end 41a of the optical fiber 41 may include light that is irradiated from the light source unit 3 and reflected by tablets W adjacent in the transport direction, as well as light other than light irradiated from the light source unit 3, for example, light that is external light at the installation location of the spectroscopic measurement device 1 and reflected by tablets W adjacent in the transport direction. In this embodiment, the cylindrical member 45 can also prevent such light from entering the incident end 41a of the optical fiber 41.

[0069] In this embodiment, even if a portion of the light reflected by the tablet W adjacent to the tablet W being measured in the transport direction enters the tubular member 45, the incident light is absorbed by the inner wall surface 45c of the tubular member 45, which has been subjected to a low-reflectivity surface treatment, and therefore the light reflected thereafter can be attenuated, as shown by the dashed arrow in Figure 3.

[0070] [Replacing the cylindrical parts] In the spectroscopic measurement device 1 of this embodiment, the cylindrical member 45 is configured to be replaceable depending on the type of article to be inspected (measured).

[0071] For example, if the object to be inspected (measured) is a tablet, the optimal size of the cylindrical member 45 can be selected and used depending on the diameter, thickness, and shape of the tablet. It is preferable that cylindrical members 45 be prepared in a variety of sizes so that the optimal combination of diameter (cylinder inner diameter) of opening 45a and axial length (cylinder length) can be selected from, for example, small, medium, and large depending on the type of tablet. The aforementioned cylindrical length refers to the length from the opening end (lower end in this embodiment) of reflective cover 43 to opening end 45b. The size types are not limited to the three levels mentioned above.

[0072] Here, some examples of the types of the cylindrical member 45 will be described.

[0073] For example, when a rectangular tablet having a small diameter, a thin thickness, and a rectangular shape is to be measured, it is preferable to use a cylindrical member 45 having a small inner diameter and a long length. In this way, when the thickness of the tablet to be measured is thin, the gap between the surface of the tablet on the light detection unit 4 side (the upper surface in this embodiment) and the open end 45b of the cylindrical member 45 becomes large, so it is preferable to use a cylindrical member 45 having a long length in order to reduce this gap.

[0074] For example, when a rectangular tablet having a small diameter and a large thickness is to be measured, it is preferable to use a cylindrical member 45 having a small inner diameter and a short length. In this way, when the thickness of the tablet to be measured is large, the amount of light transmitted through the tablet is small compared to when the tablet is thin. Therefore, it is preferable to use a short cylindrical member 45 so that the small amount of light is not significantly attenuated by the inner wall surface 45c of the cylindrical member 45.

[0075] For example, when measuring R tablets with a medium diameter, thin thickness, and curved end faces, it is preferable to use a cylindrical member 45 with a medium cylinder inner diameter and a long cylinder length. In this way, when the tablets to be measured have curved end faces, variations in transmitted light between tablets are likely to occur.

[0076] Fig. 4 is an example showing the relationship between the coefficient of variation and the distance between the object to be measured and the incident end 41a of the optical fiber 41. As shown in Fig. 4, the coefficient of variation tends to decrease as the distance between the object to be measured and the incident end 41a of the optical fiber 41 increases.

[0077] Therefore, for example, when the tablet to be measured as described above has a curved end face, it is preferable to use a cylindrical member 45 with a long cylindrical length that can reduce the coefficient of variation.

[0078] [Action and effect] As described above, in the spectroscopic measurement device according to this embodiment, the light detection unit 4 has the cylindrical member 45 between the tablet W and the optical fiber 41, the opening 45a at the end of the cylindrical member 45 on the tablet W side is positioned closer to the tablet W than the incident end 41a of the optical fiber 41, and the transmitted light passes through the opening 45a and enters the optical fiber 41. Therefore, the cylindrical member 45 can block light other than the transmitted light that is irradiated from the light source unit 3 and transmitted through the tablet W from entering the incident end 41a of the optical fiber 41. Therefore, the spectroscopic measurement device according to this embodiment can prevent stray light from entering the optical fiber 41, and can prevent a decrease in the accuracy of the spectral data of the light that enters the optical fiber 41.

[0079] Furthermore, in the spectroscopic measurement device according to this embodiment, the inner wall surface 45c of the cylindrical member 45 is subjected to a light-absorbing surface treatment, so that even if stray light enters the cylindrical member 45 from the gap between the tablet W and the cylindrical member 45 through the opening 45a of the cylindrical member 45, the stray light can be absorbed or attenuated by the inner wall surface 45c. This makes it possible to reduce stray light incident on the incident end 41a of the optical fiber 41.

[0080] Furthermore, in the spectroscopic measurement device according to this embodiment, the opening end 45b of the cylindrical member 45 is formed sharply, so that stray light can be prevented from being reflected toward the tablet W at the opening end 45b of the cylindrical member 45 facing the tablet W and then further reflected from the tablet W toward the incident end 41a of the optical fiber 41.

[0081] Furthermore, in the spectroscopic measurement device according to this embodiment, the cylindrical member 45 is configured to be replaceable depending on the type of object to be measured, so when the object to be measured is changed to a different type of object, the dimensions of the opening 45a and the axial length can be changed to an optimal cylindrical member 45 for the object depending on, for example, the shape and dimensions of the changed object. This makes it possible to prevent stray light from entering the optical fiber 41 even when the object to be measured is changed.

[0082] Furthermore, the product inspection device of this embodiment is equipped with a spectroscopic measurement device 1 that can prevent stray light from entering the optical fiber 41 and can prevent a decrease in the accuracy of the spectral data of light incident on the optical fiber 41, thereby preventing a decrease in the inspection accuracy of the quality of the tablets W by the inspection unit 2.

[0083] [Variations] In this embodiment, the shape of the opening 45a of the tubular member 45 is described as being formed into a perfect circle, but this is not limited to this. The shape of the opening 45a may be elongated in a direction perpendicular to the conveying direction of the tablet W and the dimension in the conveying direction of the tablet W is smaller than the diameter of the tablet W, for example, an oval or rectangular shape.

[0084] 5 and 6, the effect of making the shape of the opening 45a of the cylindrical member 45 elliptical or rectangular will be described using an elliptical shape having a minor axis shorter than the diameter of the tablet W in the conveying direction (moving direction) of the tablet W as an example. In Fig. 5 and Fig. 6, the tablet W moving in the conveying direction is indicated by a solid line and a two-dot chain line.

[0085] 5, when the shape of the opening 45a of the cylindrical member 45 is a perfect circle, the time during which the tablet W moving in the conveying direction overlaps the entire area of ​​the opening 45a of the cylindrical member 45 is short. Therefore, when the shape of the opening 45a of the cylindrical member 45 is a perfect circle, the light receiving area is smaller than when the shape of the opening 45a of the cylindrical member 45, which will be described later, is an ellipse.

[0086] 6, when the shape of the opening 45a of the cylindrical member 45 is elliptical, the tablets W moving in the conveying direction overlap the entire area of ​​the opening 45a of the cylindrical member 45 for a long time. Therefore, when the shape of the opening 45a of the cylindrical member 45 is elliptical, the light receiving area becomes larger compared to when the shape of the opening 45a of the cylindrical member 45 is a perfect circle. As a result, the amount of transmitted light obtained by the light detection unit 4 increases.

[0087] In this way, when the shape of the opening 45a of the cylindrical member 45 is elliptical, light can be irradiated onto the tablet W while it is moving for a longer period of time, thereby improving the accuracy of the spectral data of the light incident on the optical fiber 41.

[0088] When the tablet W has a horizontally elongated shape, the dimension of the opening 45a of the cylindrical member 45 differs between when the tablet W is transported with its major axis parallel to the transport direction and when the tablet W is transported with its minor axis parallel to the transport direction. For example, when the tablet W is transported with its major axis parallel to the transport direction, the dimension of the opening 45a in the transport direction may be shorter than the major axis of the tablet W. On the other hand, when the tablet W is transported with its minor axis parallel to the transport direction, the dimension of the opening 45a in the transport direction is made shorter than the minor axis of the tablet W.

[0089] Furthermore, in this embodiment, an example has been described in which the tubular member 45 is replaceable to accommodate changes in the object to be measured, but it is also possible to accommodate changes in the object to be measured by making the position of the incident end 41a of the optical fiber 41 adjustable in the axial direction of the tubular member 45.

[0090] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0091] 1 Spectrometer 2. Inspection Department 2a Signal processing section 3 Light source section 4. Light detection unit 10. Item inspection equipment 11 Transfer disk 30 light source 31 Light Guide 32 Optical Lenses 40 Base member 41 Optical Fiber 41a Incidence end 42 Spectrometer 43 Reflective cover 43a Reflective surface 45 Cylindrical member 45a opening 45b Open end 45c inner wall 45d Exterior wall surface W Tablet (item)

Claims

1. a light source unit (3) that irradiates light onto an article (W); a light detection unit (4) including an optical fiber (41) into which transmitted light irradiated from the light source unit and transmitted through the article is incident, and a spectroscope (42) for measuring the spectral characteristics of the transmitted light that has passed through the optical fiber, The light detection unit further includes a cylindrical member (45) between the object and the optical fiber, an opening (45a) at the end of the cylindrical member facing the object is located closer to the object than the incident end (41a) of the optical fiber, and the transmitted light passes through the cylindrical member from the opening and enters the optical fiber.

2. 2. The spectrometer according to claim 1, wherein an inner wall surface (45c) of the cylindrical member is subjected to a surface treatment for absorbing light.

3. The cylindrical member has an open end (45b) in which the opening is formed, 3. The spectrometer according to claim 1, wherein the open end is sharply formed.

4. The light source unit is configured to irradiate light onto the moving object, 3. The spectrometer according to claim 1, wherein the opening of the cylindrical member has an elliptical shape having a minor axis shorter than a diameter of the object in the moving direction of the object.

5. The light source unit is configured to irradiate light onto the moving object, The spectrometer according to claim 3 , wherein the opening of the cylindrical member has an elliptical shape having a minor axis that is shorter than a diameter of the object in the moving direction of the object.

6. 3. The spectrometer according to claim 1, wherein the cylindrical member is configured to be replaceable depending on the type of the object.

7. The spectrometer according to claim 3 , wherein the cylindrical member is configured to be replaceable depending on the type of the object.

8. The spectrometer according to claim 4 , wherein the cylindrical member is configured to be replaceable depending on the type of the object.

9. The spectrometer according to claim 5 , wherein the cylindrical member is configured to be replaceable depending on the type of the object.

10. A spectroscopic measurement device (1) according to claim 1 or claim 2; and an inspection unit (2) that inspects the quality of the article based on the spectroscopic characteristics measured by the spectrometer.

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