Spectroscopic measurement device and article inspection apparatus including the same

Abstract

To provide a spectroscopic measurement device capable of suppressing a measurement error, and an article inspection apparatus including the spectroscopic measurement device.SOLUTION: A spectroscopic measurement device 1 measures a spectral characteristic of absorbance of a tablet W by operating a light detection section 4 in two modes, a first mode of detecting the spectral characteristic of light emitted from a light source section 3 and a second mode of detecting the spectral characteristic of transmitted light emitted from the light source section 3 and transmitted through the tablet W. A spectral characteristic adjustment section 61 stores a first spectral characteristic detected at first time when the light detection section 4 operates in the first mode, and adjusts an optical system from a light source 30 to a spectroscope 42 so that a second spectral characteristic detected at second time when the light detection section 4 operates in the first mode after the first time falls within an allowable range with respect to the first spectral characteristic.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent document 1 discloses an absorbance calculation that uses the spectral characteristics of the light used to measure a tablet as a reference and the spectral characteristics when the tablet is measured as the work result, and calculates the amount of attenuation of the work result from the reference. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-018796 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology described in Patent Document 1 still has room for improvement in that measurement errors occur when the reproducibility of the light source spectrum decreases due to attenuation of light intensity caused by deterioration of the light source lamp, individual differences between light source lamps, distortion of the light source spectrum, etc.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide a spectroscopic measurement device capable of suppressing measurement errors and an article inspection device equipped with the same. [Means for solving the problem]

[0006] The spectroscopic measurement device of the present invention comprises a light source unit (3) that irradiates light emitted from a light source (30), a light detection unit (4) that detects the spectral characteristics of the incident light using a spectrometer (42), and a spectral characteristic adjustment unit (61) that adjusts the spectral characteristics detected by the light detection unit. The spectroscopic measurement device measures the spectral characteristics of the absorbance of an item by operating the light detection unit in two modes: a first mode that detects the spectral characteristics of the light irradiated from the light source unit, and a second mode that detects the spectral characteristics of the transmitted light that is irradiated from the light source unit and transmitted through the item (W). The spectral characteristic adjustment unit is configured to store a first spectral characteristic detected at a first time when the light detection unit is operating in the first mode, and to adjust the optical system from the light source to the spectrometer so that a second spectral characteristic detected at a second time after the first time when the light detection unit is operating in the first mode is within an acceptable range for the first spectral characteristic.

[0007] With this configuration, the spectroscopic measurement device according to the present invention adjusts the optical system so that the spectral characteristics of the light source reproduce the first spectral characteristics, thereby making it possible to suppress measurement errors.

[0008] In addition, in the spectroscopic measurement device according to the present invention, the light source may emit light when power is supplied thereto, and the spectral characteristic adjustment unit may adjust the distortion of the second spectral characteristic by adjusting the power supplied to the light source.

[0009] With this configuration, the spectroscopic measurement device according to the present invention adjusts the temperature of the light source by adjusting the power supplied to the light source, and therefore can change the distortion of the second spectral characteristic that accompanies changes in the temperature of the light source.

[0010] In addition, in the spectroscopic measurement device according to the present invention, the light source unit may have a light guide (31) that guides light from the light source to an optical lens (32), and the spectral characteristic adjustment unit may adjust the level of the second spectral characteristic by adjusting the distance between a tip surface (31 a) of the light guide and the optical lens.

[0011] With this configuration, the spectroscopic measurement device according to the present invention can adjust the level of the second spectral characteristic by adjusting the distance between the tip surface of the light guide and the optical lens.

[0012] Furthermore, in the spectroscopic measurement device according to the present invention, the light detection unit may have a light variable unit (53) that varies the level of light incident on the spectrometer, and the spectral characteristic adjustment unit may adjust the level of the second spectral characteristic using the light variable unit.

[0013] With this configuration, the spectroscopic measurement device according to the present invention can adjust the level of the second spectral characteristic by adjusting the level of the light incident on the spectroscope using the light variable section.

[0014] In addition, the article inspection device according to the present invention comprises the above-mentioned spectroscopic measurement device (1) and an inspection unit (2) that inspects the quality of the article based on the spectroscopic characteristics of the absorbance of the article measured by the spectroscopic measurement device.

[0015] With this configuration, the article inspection device according to the present invention can accurately inspect the quality of articles because the spectroscopic measurement device can suppress measurement errors. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a spectroscopic measurement device capable of suppressing measurement errors and an article inspection device equipped with the same. [Brief explanation of the drawings]

[0017] [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 graph for explaining the adjustment effect by the spectral characteristic adjustment unit constituting the spectroscopic measurement device according to one embodiment of the present invention, in which (a) shows the first spectral characteristic and the second spectral characteristic before adjustment, and (b) shows the first spectral characteristic and the second spectral characteristic after adjustment. DETAILED DESCRIPTION OF THE INVENTION

[0018] 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.

[0019] 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).

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] The article inspection device 10 according to this embodiment includes a spectroscopic measurement device 1 and an inspection unit 2.

[0025] [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.

[0026] (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).

[0027] 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.

[0028] The light source unit 3 includes a light source 30 , a light guide 31 , and an optical lens 32 .

[0029] The light source 30 is configured with a broadband light source such as a halogen lamp to emit 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). The light source 30 emits light when power is supplied from the power supply unit.

[0030] 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.

[0031] The light guide 31 is made up of a large number of flexible glass optical fibers bundled together, and guides light from the light source 30 to an optical lens 32 that focuses the light. The optical lens 32 focuses the light from the light guide 31 onto the tablet W at a predetermined inspection position (the underside of the tablet W in the example of FIG. 1). The light emitted from the light source 30 is irradiated onto the tablet W via the light guide 31 and the optical lens 32.

[0032] The light guide 31 has a tip surface 31a facing the optical lens 32 at the end opposite to the light source 30 (upper side in this embodiment). Light emitted from the light source 30 is emitted from the tip surface 31a of the light guide 31 towards the optical lens 32. In this embodiment, the tip surface 31a means the tip surface of the light guide in which glass optical fibers are bundled together, and does not include the outer periphery that covers the tip surface.

[0033] A support member 51 that supports the tip surface 31a side of the light guide 31 is provided on the side surface of the tip surface 31a side of the light guide 31. The position of the tip surface 31a of the support member 51 is adjusted by an adjustment unit 52.

[0034] The adjustment unit 52 is provided so as to be able to adjust the position of the tip surface 31a of the support member 51 in the optical axis direction (in the vertical direction in this embodiment). In this manner, the adjustment unit 52 adjusts the distance between the tip surface 31a of the light guide 31 and the optical lens 32.

[0035] The adjustment unit 52 may be any mechanism that can adjust the position of the support member 51. In this embodiment, the adjustment unit 52 has an adjustment mechanism such as a rack-and-pinion mechanism or a ball screw mechanism, and an actuator that drives the adjustment mechanism.

[0036] (Photodetector) The light detecting section 4 has an optical fiber 41 and a spectroscope 42. In the light detecting section 4, the optical fiber 41 and the spectroscope 42 are unitized.

[0037] 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.

[0038] The optical fiber 41 is configured to receive transmitted light that has passed through the tablet W at a predetermined inspection position. The transmitted light that has passed through the tablet W enters the optical fiber 41 from the end face on the incident side 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.

[0039] The optical fiber 41 is provided with a light variable section 53 that varies the level of light passing through the optical fiber 41. In this embodiment, the light variable section 53 is configured by an attenuator. Note that the light variable section 53 may be configured by an optical amplifier, or may be configured by a combination of an attenuator and an optical amplifier.

[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 the transmitted light irradiated from the light source unit 3 and transmitted through the tablet W via the optical fiber 41, and measures the spectral characteristics of the transmitted light received via the optical fiber 41 using the spectroscope .

[0043] [Control device] The article inspection device 10 has a control device 60. The control device 60 is configured by a computer device having, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a storage device such as a hard disk device, an input / output port, and a communication port.

[0044] The ROM and storage device of this computer device store a program for causing the computer device to function as the control device 60. That is, the CPU executes the program stored in the ROM using the RAM as a work area, causing the computer device to function as the control device 60. In this embodiment, the control device 60 functions as a spectral characteristics adjustment unit 61 and an inspection unit 2.

[0045] (Spectral characteristics adjustment section) The spectral characteristics adjustment unit 61 adjusts the spectral characteristics detected by the light detection unit 4. For example, the spectral characteristics adjustment unit 61 standardizes the spectral characteristics detected by the light detection unit 4. The standardization performed by the spectral characteristics adjustment unit 61 includes at least one of the four arithmetic operations, differentiation, integration, and normalization.

[0046] The spectral characteristic adjustment unit 61 standardizes the spectral characteristics detected by the light detection unit 4 in the first mode in which the spectral characteristics of the light irradiated from the light source unit 3 are detected, and stores the standardized spectral characteristics (hereinafter simply referred to as the "first spectral characteristics") in the storage device as a reference.

[0047] The spectral characteristic adjustment unit 61 standardizes the spectral characteristics detected by the light detection unit 4 in the second mode in which the spectral characteristics of the transmitted light irradiated from the light source unit 3 and transmitted through the tablet W are detected, and calculates the spectral characteristics of the absorbance of the tablet W using the standardized spectral characteristics (hereinafter also simply referred to as "transmitted spectral characteristics") and the first spectral characteristics.

[0048] For example, the spectral characteristic adjusting unit 61 calculates the absorbance A of the tablet W at each wavelength λ from the light intensity Ii at the wavelength λ of the first spectral characteristic and the light intensity I at the wavelength λ of the transmission spectral characteristic as A=-log 10 The spectroscopic characteristics of the absorbance of tablet W are calculated according to (I / Ii).

[0049] When measuring the spectroscopic characteristics of absorbance of a new variety of tablet W, the position and components of the measurement system including the light source unit 3 and the light detection unit 4 are adjusted according to the variety of tablet W. Therefore, after the measurement system is adjusted to measure the spectroscopic characteristics of absorbance of a new variety of tablet W, a new reference needs to be stored in the storage device.

[0050] Therefore, at a first time after the measurement system is adjusted to measure the spectroscopic characteristics of the absorbance of a new variety of tablet W, the spectroscopic characteristic adjustment unit 61 stores in the storage device a first spectroscopic characteristic that has been standardized for the spectroscopic characteristic detected by the light detection unit 4 in the first manner as a reference, in association with the new variety.

[0051] When measuring the spectroscopic characteristics of the absorbance of a tablet W of a variety that has already been measured, a measurement system including the light source unit 3 and the light detection unit 4 is adjusted according to the variety that has already been measured. After this adjustment, the spectroscopic characteristics (hereinafter also simply referred to as "second spectroscopic characteristics") obtained by standardizing the spectroscopic characteristics detected by the light detection unit 4 in the first mode may differ from the first spectroscopic characteristics stored in the storage device. The difference between the first spectroscopic characteristics and the second spectroscopic characteristics may arise due to errors in the measurement system, deterioration of the light source 30, replacement of the light source 30, etc.

[0052] The spectral characteristics adjustment unit 61 standardizes the spectral characteristics detected by the light detection unit 4 in the first mode at a second time that is later than the first time, to obtain a second spectral characteristic. The second time may be any time that is later than the first time and is when the light detection unit 4 is operating in the first mode.

[0053] For example, the second time may be the time when the light detection unit 4 is operating in the first mode after the measurement system has been adjusted according to the measured variety, or the time when the light detection unit 4 is operating in the first mode during maintenance of the item inspection device 10.

[0054] The spectral characteristic adjustment unit 61 adjusts the optical system from the light source 30 to the spectroscope 42 so that the second spectral characteristic falls within an acceptable range with respect to the first spectral characteristic. For example, the spectral characteristic adjustment unit 61 calculates the root mean square error of the second spectral characteristic with respect to the first spectral characteristic, and determines that the second spectral characteristic falls within an acceptable range with respect to the first spectral characteristic if the calculated value is less than a predetermined threshold, and determines that the second spectral characteristic does not fall within an acceptable range with respect to the first spectral characteristic if the calculated value is equal to or greater than the predetermined threshold.

[0055] For example, the spectral characteristic adjustment unit 61 controls the power supply unit to adjust the power supplied to the light source 30, thereby adjusting the distortion of the second spectral characteristic. Furthermore, the spectral characteristic adjustment unit 61 controls the adjustment unit 52 to adjust the distance between the tip surface 31a of the light guide 31 and the optical lens 32, thereby adjusting the level of the second spectral characteristic. Furthermore, the spectral characteristic adjustment unit 61 controls the light variable unit 53 to adjust the level of the second spectral characteristic.

[0056] In this embodiment, the spectral characteristic adjustment unit 61 adjusts the level of the second spectral characteristic by controlling the adjustment unit 52 and the light variable unit 53, but the level of the second spectral characteristic may also be adjusted by controlling the adjustment unit 52, or the level of the second spectral characteristic may also be adjusted by controlling the light variable unit 53.

[0057] Here, there are physical limits to the power supplied to the light source 30, the distance between the tip surface 31a of the light guide 31 and the optical lens 32, and the level that can be adjusted by the light variable unit 53. If the second spectral characteristic cannot be brought into an allowable range with respect to the first spectral characteristic due to such physical limits, the spectral characteristic adjustment unit 61 may issue an alarm via a display device or speaker device connected to the control device 60.

[0058] For example, when a first spectral characteristic 70 and a second spectral characteristic 71 are obtained as shown in FIG. 2(a), a distortion 72 of the second spectral characteristic 71 relative to the first spectral characteristic 70 and a level difference 73 of the second spectral characteristic 71 relative to the first spectral characteristic 70 are adjusted by the spectral characteristic adjustment unit 61, so that the second spectral characteristic 71 falls within an allowable range relative to the first spectral characteristic 70 as shown in FIG. 2(b).

[0059] (Inspection Department) 1, the inspection unit 2 compares the spectroscopic characteristics of absorbance of a non-defective tablet W acquired in advance with the spectroscopic characteristics of absorbance of the tablet W to be inspected that has been transported to a predetermined inspection position, and determines the quality of the tablet W based on the magnitude of the difference. The inspection unit 2 outputs a sorting signal based on the pass / fail result of the determination to a sorting unit (not shown) that sorts the tablets W into normal and defective products.

[0060] 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.

[0061] As described above, the spectroscopic measurement device 1 according to this embodiment adjusts the optical system so that the spectral characteristics of the light source 30 reproduce the first spectral characteristics, and therefore can suppress measurement errors.

[0062] Furthermore, the spectroscopic measurement device 1 according to this embodiment adjusts the temperature of the light source 30 by adjusting the power supplied to the light source 30, and therefore can change the distortion of the second spectral characteristic that accompanies changes in the temperature of the light source 30.

[0063] Furthermore, the spectroscopic measurement device 1 according to this embodiment can adjust the level of the second spectral characteristic by adjusting the distance between the tip surface 31a of the light guide 31 and the optical lens 32.

[0064] Furthermore, the spectroscopic measurement device 1 according to this embodiment can adjust the level of the second spectral characteristic by using the light variable unit 53 to adjust the level of the light incident on the spectroscope .

[0065] Furthermore, in the article inspection device 10 according to this embodiment, the spectroscopic measurement device 1 can suppress measurement errors, so that the quality of an article can be inspected with high precision.

[0066] In the present embodiment, an example has been described in which the spectral characteristic adjustment unit 61 determines whether the second spectral characteristic falls within the allowable range with respect to the first spectral characteristic by calculating the root mean square error of the second spectral characteristic with respect to the first spectral characteristic.

[0067] In contrast to this, the spectral characteristic adjustment unit 61 may determine whether the second spectral characteristic is within the allowable range for the first spectral characteristic by calculating the mean square error, the mean absolute error, the average error, the predicted standard error, the coefficient of determination, or the coefficient of determination corrected for the degrees of freedom, instead of the root mean square error.

[0068] Furthermore, the spectral characteristic adjustment unit 61 may determine whether the difference in level of the second spectral characteristic with respect to the first spectral characteristic at each wavelength in a predetermined range is within a predetermined range, thereby determining whether the second spectral characteristic is within an acceptable range with respect to the first spectral characteristic.

[0069] In the present embodiment, the example has been described in which the spectral characteristics adjustment unit 61 adjusts the optical system so that the standardized second spectral characteristics are within the allowable range for the standardized first spectral characteristics. However, the spectral characteristics adjustment unit 61 may adjust the optical system so that the pre-standardized second spectral characteristics are within the allowable range for the pre-standardized first spectral characteristics.

[0070] While embodiments of the present invention have been disclosed above, it will be apparent to those skilled in the art that modifications may be made without departing from the scope of the present invention. All such modifications and equivalents are intended to be encompassed by the following claims. [Explanation of symbols]

[0071] 1 Spectrometer 2. Inspection Department 3 Light source section 4. Light detection unit 10. Item inspection equipment 30 light source 31 Light Guide 31a Light guide tip surface 32 Optical Lenses 42 Spectrometer 53 Variable light section 61 Spectral characteristics adjustment section W Tablet (item)

Claims

1. a light source unit (3) that irradiates light emitted from a light source (30); a light detection unit (4) that detects the spectral characteristics of incident light using a spectroscope (42); a spectral characteristic adjusting unit (61) that adjusts the spectral characteristics detected by the light detecting unit, a first mode for detecting a spectral characteristic of light irradiated from the light source unit; a first mode for detecting the spectral characteristics of transmitted light irradiated from the light source unit and transmitted through the object (W), and a second mode for detecting the spectral characteristics of transmitted light irradiated from the light source unit and transmitted through the object (W), The spectral characteristics adjustment unit storing a first spectral characteristic detected at a first time when the light detection unit is operating in a first mode; and adjusting an optical system from the light source to the spectrometer so that a second spectral characteristic detected at a second time, when the light detection unit is operating in a first manner after the first time, is within an acceptable range for the first spectral characteristic.

2. the light source emits light when power is supplied thereto; The spectral characteristics adjustment unit The spectroscopic measurement device according to claim 1 , wherein the distortion of the second spectral characteristic is adjusted by adjusting the power supplied to the light source.

3. The light source unit has a light guide (31) that guides light from the light source to an optical lens (32), The spectral characteristics adjustment unit 3. The spectroscopic measurement device according to claim 1, wherein the level of the second spectral characteristic is adjusted by adjusting a distance between a tip surface (31a) of the light guide and the optical lens.

4. The light detection unit has a light variable unit (53) that varies the level of light incident on the spectroscope, The spectral characteristics adjustment unit The spectroscopic measurement device according to claim 1 or 2, wherein the level of the second spectral characteristic is adjusted by the light variable unit.

5. A spectroscopic measuring device (1) according to claim 1, and an inspection unit (2) that inspects the quality of the item based on the spectroscopic characteristics of the absorbance of the item measured by the spectroscopic measurement device.

Images