Calibration apparatus for spectrometer, article inspection apparatus with the same, and calibration method for spectrometer

Abstract

To provide a calibration apparatus for spectrometers that enables measurement reproducibility among different spectrometers, an article inspection apparatus with the calibration apparatus, and a calibration method for spectrometers.SOLUTION: A calibration apparatus for spectrometers that measures the intensity of incident light for each wavelength, includes: a light source part that irradiates a spectrometer B, which is the calibration target, with light having a known spectrum; a storage part that stores a reference wavelength conversion formula FA defining a relation between each sensor and wavelength when a spectrometer A, serving as the reference, is irradiated with light having a known spectrum from the light source part; a calculation part that calculates a wavelength conversion formula FB for the calibration target by irradiating the spectrometer B with light having a known spectrum from the light source part and defining a relation between each sensor and wavelength; and a calibration part that determines a difference between the stored wavelength conversion formula FA and the wavelength conversion formula FB, and calibrates the spectrometer B by adding the difference as a correction coefficient Cλ to the wavelength conversion formula FB.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a spectrometer calibration device, an article inspection device including the same, and a spectrometer calibration method. [Background technology]

[0002] Patent Document 1 discloses a spectroscopic measurement device that includes a light irradiation unit that irradiates a mounting surface on which an object to be measured is placed with broadband light from a light source via a light guide, and a light detection unit that detects the light that has passed through the object to be measured and is incident on a spectroscope via an optical fiber, and measures the spectroscopic characteristics using the spectroscope. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7270582 Summary of the Invention [Problem to be solved by the invention]

[0004] A spectroscope such as that used in the spectroscopic measurement device described in Patent Document 1 separates incident light into wavelengths using a spectroscopic element such as a grating, and receives the separated light into wavelengths using sensors located at positions corresponding to each wavelength. These sensors are configured in an array arranged in one direction so as to receive light of the corresponding wavelength depending on their position relative to the spectroscopic element, and convert the light intensity of the corresponding wavelength into a voltage signal for output.

[0005] Here, the relationship between each sensor arranged in an array and wavelength is defined by a wavelength conversion formula, and spectral information can be obtained by converting between the sensor and wavelength using this wavelength conversion formula.

[0006] However, spectrometers have individual differences in their components. For example, if a spectrometer is replaced, the wavelength conversion formula will be different between the spectrometer before and after the replacement, and there is a risk that the spectral information obtained from each sensor will differ between the spectrometer before and after the replacement.

[0007] In this case, even if light with the same light intensity and the same spectral distribution is incident on a spectrometer, if the spectrometers are different, differences will occur in the spectral characteristics output between the different spectrometers, and there is a risk that measurements will not be reproducible between the spectrometers.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a spectrometer calibration device that can obtain measurement reproducibility between different spectrometers, an article inspection device equipped with the same, and a spectrometer calibration method. [Means for solving the problem]

[0009] The spectrometer calibration device according to the present invention measures the light intensity of the incident light for each wavelength by decomposing incident light into wavelengths using a spectroscopic element (41) and receiving the decomposed light with sensors arranged at positions corresponding to each wavelength, and includes: a light source unit (3) that irradiates a spectrometer (40, B) to be calibrated with light having a known spectrum; a memory unit (23) that stores a reference wavelength conversion formula that defines the relationship between each sensor and wavelength when a reference spectrometer (40, A) is irradiated with light having the known spectrum from the light source unit; a calculation unit (22) that irradiates the spectrometer to be calibrated with light having the known spectrum from the light source unit and calculates the wavelength conversion formula for the spectrometer to be calibrated that defines the relationship between each sensor and wavelength; and a calibration unit (24) that calibrates the spectrometer to be calibrated by determining the difference between the reference wavelength conversion formula stored in the memory unit and the wavelength conversion formula for the spectrometer to be calibrated and adding the difference as a correction coefficient (C) to the wavelength conversion formula for the spectrometer to be calibrated.

[0010] With this configuration, the spectrometer calibration device of the present invention calibrates the spectrometer to be calibrated by irradiating the spectrometer to be calibrated with light having a known spectrum from the light source unit, calculating a wavelength conversion formula for the spectrometer to be calibrated that defines the relationship between each sensor and wavelength, determining the difference between the calculated wavelength conversion formula for the spectrometer to be calibrated and the reference wavelength conversion formula stored in the memory unit, and adding this difference as a correction coefficient to the wavelength conversion formula for the spectrometer to be calibrated.Therefore, it is possible to cancel differences in the spectral characteristics output between different spectrometers, and to obtain measurement reproducibility between different spectrometers.

[0011] In the spectrometer calibration device according to the present invention, the calibration unit calculates a difference in wavelength for each sensor based on the reference wavelength conversion formula stored in the storage unit and the wavelength conversion formula of the calibration target, and calculates the difference as a correction coefficient (C λ ) into the wavelength conversion formula of the calibration target, thereby calibrating the spectroscope to be calibrated.

[0012] With this configuration, the spectrometer calibration device of the present invention calibrates the spectrometer to be calibrated by calculating the wavelength difference for each sensor based on the reference wavelength conversion formula stored in the memory unit and the wavelength conversion formula to be calibrated, and adding this difference as a correction coefficient to the wavelength conversion formula to be calibrated, thereby making it possible to cancel out wavelength differences that occur for each sensor between different spectrometers, and to cancel out differences that occur in the spectral characteristics output between different spectrometers.

[0013] In the spectrometer calibration device according to the present invention, the calibration unit calculates a difference between a unique sensor number (P) for identifying each sensor for each wavelength based on the reference wavelength conversion formula stored in the storage unit and the wavelength conversion formula to be calibrated, and calculates the difference as a correction coefficient (C PN ) into the wavelength conversion formula of the calibration target, thereby calibrating the spectroscope to be calibrated.

[0014] With this configuration, the spectrometer calibration device of the present invention calibrates the spectrometer to be calibrated by calculating the difference in the unique sensor number that identifies each sensor for each wavelength based on the reference wavelength conversion formula stored in the memory unit and the wavelength conversion formula to be calibrated, and adding this difference as a correction coefficient to the wavelength conversion formula to be calibrated, thereby making it possible to cancel out the difference in sensor number that occurs for each wavelength between different spectrometers and to cancel out the difference that occurs in the spectral characteristics output between different spectrometers.

[0015] The object inspection device according to the present invention comprises a spectrometer calibration device according to any one of claims 1 to 3, and an inspection unit (21) that inspects the quality of an object (W) based on the spectroscopic characteristics measured by the spectrometer.

[0016] With this configuration, the item inspection device of the present invention is equipped with a spectrometer calibration device that can obtain measurement reproducibility between different spectrometers, so that the accuracy of inspection in the inspection unit does not vary between different spectrometers and the accuracy of inspection in the inspection unit can be improved.

[0017] A method for calibrating a spectrometer according to the present invention is a method for measuring the light intensity of incident light for each wavelength by decomposing incident light into wavelengths using a spectroscopic element (41) and receiving the decomposed light with sensors arranged at positions corresponding to each wavelength. The spectrometer calibration device includes: a light source unit (3) that irradiates a spectrometer (40, B) to be calibrated with light having a known spectrum; a memory unit (23) that stores a reference wavelength conversion formula that defines the relationship between each sensor and wavelength when a reference spectrometer (40, A) is irradiated with light having the known spectrum from the light source unit; a calculation unit (22) that irradiates the spectrometer to be calibrated with light having the known spectrum from the light source unit and calculates the wavelength conversion formula to be calibrated that defines the relationship between each sensor and wavelength; and a calibration unit (24) that calibrates the spectrometer to be calibrated. The calibration unit is configured to calibrate the spectrometer to be calibrated by calculating the difference between the reference wavelength conversion formula stored in the memory unit and the wavelength conversion formula to be calibrated, and adding the difference as a correction coefficient (C) to the wavelength conversion formula to be calibrated.

[0018] With this configuration, the spectrometer calibration method of the present invention irradiates the spectrometer to be calibrated with light having a known spectrum from the light source unit, calculates a wavelength conversion formula for the spectrometer to be calibrated that defines the relationship between each sensor and wavelength, determines the difference between the calculated wavelength conversion formula for the spectrometer to be calibrated and the reference wavelength conversion formula stored in the memory unit, and adds this difference as a correction coefficient to the wavelength conversion formula for the spectrometer to be calibrated, thereby calibrating the spectrometer to be calibrated.Therefore, it is possible to cancel differences in the spectral characteristics output between different spectrometers, and to obtain measurement reproducibility between different spectrometers. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a spectrometer calibration device that can obtain measurement reproducibility between different spectrometers, an article inspection device equipped with the same, and a spectrometer calibration method. [Brief explanation of the drawings]

[0020] [Figure 1]FIG. 1 is a schematic diagram of an article inspection device equipped with a spectrometer calibration device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing the relationship between a spectroscopic element and a sensor in an article inspection device equipped with a spectrometer calibration device according to one embodiment of the present invention. [Figure 3] FIG. 3 is a graph showing the relationship between pixel number and light intensity in an example of the spectral characteristics of light measured by a spectroscope of an article inspection device equipped with a spectroscope calibration device according to one embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram showing an example of calibration of a spectroscope in an article inspection device equipped with a spectroscope calibration device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

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

[0022] In this embodiment, as an example of an item inspection device that irradiates light onto an item W to be inspected, detects the transmitted light that has passed through the item W, and inspects the item W based on the detected transmitted light, we will describe an item inspection device 10 that, when an item W to be inspected is transported individually along a transport path by a transport unit and reaches a predetermined inspection position, irradiates light onto the item W, which is in a fixed posture at the predetermined inspection position, and inspects the quality of the item W based on the spectral characteristics of the transmitted light that has passed through the item W as a result of the irradiation of this light.

[0023] The object inspection device of this embodiment may be, for example, an object inspection device that irradiates the object W to be inspected with visible light, infrared light, etc., detects the transmitted light that passes through the object W, and inspects the object W based on a transmitted image obtained from the detected transmitted light.

[0024] The object W to be inspected is an object of a size relatively close to the area irradiated with light, and includes objects with an outer diameter φ of several mm to several tens of mm that can be transported individually without packaging, bite-sized objects, objects of a predetermined shape or molded products manufactured using existing manufacturing equipment or manufacturing equipment without inspection functions, and particularly objects whose shape does not change during transportation.

[0025] Examples of the relevant article W include pharmaceutical preparations such as tablets, capsules, lozenges, drops, candy, chocolate, and the like.

[0026] Examples of the conveying unit include a conveying belt, a conveying disk, a conveying chute, and the like, which are configured to align the articles W and convey them individually.

[0027] As shown in FIG. 1, an article inspection device 10 according to this embodiment includes a spectroscopic measurement device 1 and a control device 2.

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

[0029] (Light source part) The light source unit 3 is configured to irradiate a wideband light onto an article W passing through a predetermined inspection position, i.e., an article W being conveyed (moving). In this embodiment, the light source unit 3 is disposed on the opposite side of the conveyance path of the article W from the light detection unit 4.

[0030] The conveyance path of the article W is an area through which the article W passes during conveyance. The predetermined inspection position is a position on the conveyance path of the article 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 and an optical system (not shown) that includes a light guide and an optical lens.

[0032] The light source 30 is, for example, a broadband light source that irradiates the object W to be measured with broadband light, and is configured to be able to irradiate light having a known spectrum. Here, light having a known spectrum refers to light that has peaks at multiple specific wavelengths, and the wavelengths of these peaks are known.

[0033] Broadband light refers to visible light and light from near-infrared to terahertz (light including terahertz waves). Note that the wavelength of the irradiated light does not need to cover all of these; for example, the wavelength band of 400-2500 nm can easily transmit through the object to be measured, such as a tablet, and is less likely to cause damage from ultraviolet rays, so it may be limited to this wavelength band or the near-infrared band within this wavelength band.

[0034] (Photodetector) The light detection unit 4 has a spectroscope 40 and an optical system (not shown) including an optical fiber. The light detection unit 4 is disposed on the opposite side of the light source unit 3 across the conveyance path of the article W. The transmitted light that has passed through the article W enters the optical fiber, passes through the optical fiber, and reaches (enters) the spectroscope 40.

[0035] As shown in FIG. 2, the spectrometer 40 includes a spectroscopic element 41 and a plurality of sensors P0 to P n and a sensor array 42 in which the sensors are arranged in one direction.

[0036] The spectroscopic element 41 divides the light incident on the spectrometer 40 (hereinafter referred to as "incident light") into wavelengths λ0 to λ1. n The spectroscopic element 41 can be, for example, a grating that utilizes the difference in diffraction angle depending on the wavelength of light, or a prism that disperses light by utilizing the difference in refractive index for each wavelength. In this embodiment, an example will be described in which a grating is used as the spectroscopic element 41. A grating is an optical element with multiple grooves engraved on its surface.

[0037] The sensor array 42 detects the wavelengths λ0 to λ1 of the light resolved by the spectroscopic element 41. n Sensors P0 to P nare arranged. Sensors P0 to P n is a photodetector element.

[0038] The light that enters the spectrometer 40 is irradiated onto a grating (diffraction grating) and split into individual wavelength components. The split light is then directed to sensors P0 to P1 arranged in a row. n Then, the light intensity of each wavelength component is measured.

[0039] In this way, the light detection unit 4 receives light emitted from the light source unit 3 and transmitted through the object W, and then enters an optical fiber, and measures the spectral characteristics of the transmitted light that has passed through the optical fiber using the spectrometer 40.

[0040] [Control device] The control device 2 is configured by a computer unit that includes at least a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an input port, and an output port.

[0041] In addition to the light source unit 3 and light detection unit 4 mentioned above, the control device 2 is connected to various sensors such as a tablet detection sensor that detects the item W being transported, a drive motor (not shown) that drives the transport unit, and an operation display unit (not shown).

[0042] The operation display unit is configured, for example, by a touch panel display. The operation display unit functions as a display unit that displays various information in addition to a viewer display screen related to the management of each item W, and also functions as an operation unit that accepts various operations such as adjustment operations from the user. User operations include, for example, various setting operations, operating operations, and selection operations.

[0043] (Inspection Department) The control device 2 has a function as an inspection unit 21 that inspects the article W based on the spectral characteristics of the light transmitted through the article W measured by the spectroscope 40.

[0044] The inspection unit 21 has a signal processing unit (not shown) that processes the spectroscopic characteristics measured by the spectrometer 40 within a predetermined exposure time, and inspects the quality of the item W, i.e., determines whether the quality of the item W is good or bad, based on the results of the signal processing.

[0045] The signal processing unit calculates the spectral characteristics of the absorbance absorbed by the article W from the spectral characteristics measured by the spectrometer 40. 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 the article W is not present at the predetermined inspection position can be calculated as the light intensity Ii of the incident light.

[0046] The inspection unit 21 compares the spectroscopic characteristics of absorbance of a non-defective item W (intensity of each wavelength in the spectrum (including multiple differentiations), waveform shape, information extracted from the entire or partial region and converted into a calibration curve, statistical information) acquired in advance with the spectroscopic characteristics of absorbance of the item W to be inspected and transported to a predetermined inspection position, and determines whether the quality of the item W is good or bad based on the magnitude of the difference. The inspection unit 21 outputs a sorting signal based on the pass / fail result of this determination to a sorting unit (not shown) that sorts the item W into normal or defective items.

[0047] Specifically, the quality of the article 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 a calibration curve).The quality of the article 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 article W are uniform, the quality of the article 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.

[0048] The control device 2 has a calculation unit 22, a storage unit 23, and a calibration unit 24 as one function of a spectrometer calibration device.

[0049] (Calculation section) The calculation unit 22 irradiates the spectrometer 40 with light having a known spectrum from the light source unit 3 and calculates the values ​​of the respective sensors P0 to P n and wavelengths λ0 to λ n Calculate the wavelength conversion formula that defines the relationship between each sensor P0 and P n are distinguished by a unique sensor number (hereinafter referred to as a "pixel number") that identifies each sensor.

[0050] In this embodiment, the wavelength conversion formula can be determined from a spectrum having a known peak wavelength, for example, as shown in FIG. 3, and is formed of, for example, a fifth-order polynomial.

[0051] (Storage part) The storage unit 23 stores the wavelength conversion formula calculated by the calculation unit 22, and stores at least the wavelengths of the sensors P0 to P1 when the light source unit 3 irradiates the reference spectrometer 40 with light having a known spectrum. n and wavelengths λ0 to λ n The reference wavelength conversion formula that defines the relationship between the wavelength and the wavelength of the light is stored.

[0052] For example, when the spectrometer 40 is replaced, the reference spectrometer 40 is the spectrometer 40 before replacement, i.e., the spectrometer 40 that was installed at the time of shipment of the article inspection device 10. In this embodiment, the spectrometer 40 that was installed at the time of shipment serves as the reference spectrometer for all spectrometers that are subsequently replaced. Therefore, for example, when the spectrometer 40 is replaced, all of the replaced spectrometers 40 are calibrated so that their output characteristics (spectral characteristics that are output) are the same as those of the reference spectrometer 40.

[0053] The storage unit 23 stores the values ​​of the sensors P0 to P1 when the light source unit 3 irradiates the spectrometer 40 to be calibrated with light having a known spectrum. n and wavelengths λ0 to λ n The wavelength conversion formula for the calibration object that defines the relationship between

[0054] (Proofreading Department) The calibration unit 24 calculates the difference between the reference wavelength conversion formula stored in the memory unit 23 and the wavelength conversion formula to be calibrated, and adds the difference as a correction coefficient C to the wavelength conversion formula to be calibrated, thereby calibrating the spectrometer 40 to be calibrated.

[0055] Specifically, the calibration unit 24 calculates the wavelengths of the sensors P0 to P1 based on the reference wavelength conversion formula stored in the storage unit 23 and the wavelength conversion formula to be calibrated. n The wavelength difference is calculated for each wavelength, and the difference in wavelength is used as the correction coefficient C λ The spectrometer 40 to be calibrated is calibrated by adding the above equation to the wavelength conversion formula to be calibrated.

[0056] [Spectrometer calibration device] The article inspection device 10 according to this embodiment also functions as a spectrometer calibration device. That is, in the article inspection device 10 according to this embodiment, the light source unit 3, light detection unit 4, calculation unit 22, storage unit 23, and calibration unit 24 described above constitute the spectrometer calibration device.

[0057] [Spectrometer calibration procedure] Next, referring to Figure 4, the calibration procedure for the spectrometer 40 performed by the spectrometer calibration device provided in the item inspection device 10 of this embodiment will be explained using an example in which the spectrometer 40 is replaced from the reference spectrometer A to the spectrometer B to be calibrated.

[0058] Light source 30 is the same before and after the change from spectrometer A to spectrometer B, and the spectral characteristics of the light irradiated to spectrometer A are the same as those of the light irradiated to spectrometer B. Furthermore, the spectrum of the light irradiated from light source 30 has multiple peak wavelengths in the wavelength range of the spectrometer, in other words, it is a spectrum with known spectral characteristics in which multiple emission lines are produced.

[0059] The storage unit 23 of the control device 2 stores the wavelength conversion formula F of the reference spectrometer A. A (See the following formula (1)) is stored in advance as a standard wavelength conversion formula. Ais a fifth-order polynomial, and is calculated, for example, at the time of shipping the article inspection device 10 and stored in the storage unit 23. In the spectrometer A, the wavelength conversion formula F A By using the above formula, the wavelength λ of the sensor of any pixel number can be obtained.

[0060] [Number 1] λ=C A0 +C A1 *P+C A2 *P 2 +C A3 *P 3 +C A4 *P 4 +C A5 *P 5 ···(1) λ: wavelength of the sensor with any pixel number C An : A coefficient specific to spectrometer A (n is 0 or a positive integer) P: Pixel number

[0061] Here, when spectrometer 40 is replaced with a different spectrometer B, if there is an individual difference between spectrometer A and spectrometer B, the individual difference will result in a difference in the spectral characteristics output from each spectrometer. The "individual difference" here refers to, for example, individual differences in the components of the spectrometer, such as the slit, grating, sensor, and housing, and individual differences caused by assembly errors of these components.

[0062] Therefore, in this embodiment, in order to cancel the difference in spectroscopic characteristics occurring between the spectrometer A and the spectrometer B, the spectrometer B after replacement is calibrated.

[0063] To calibrate the spectroscope B, first, the control device 2 irradiates the spectroscope B with light having a known spectrum from the light source unit 3, and measures the intensity of each of the sensors P0 to P1. n and wavelengths λ0 to λ n The wavelength conversion formula F defines the relationship between B (See the following formula (2)) is calculated as the wavelength conversion formula for the calibration target. Wavelength conversion formula F B is stored in the storage unit 23 of the control device 2.

[0064] [Number 2] λ=C B0 +C B1 *P+C B2 *P 2 +C B3 *P 3 +C B4 *P 4 +C B5 *P 5 ···(2) λ: wavelength of the sensor with any pixel number C Bn : A coefficient specific to spectrometer B (n is 0 or a positive integer) P: Pixel number

[0065] Next, the control device 2 calculates the wavelength conversion formula F stored in the storage unit 23. A and wavelength conversion formula F B Based on this, each sensor P0 to P n The wavelength difference is calculated for each pixel, i.e., for each pixel number.

[0066] Then, the control device 2 calculates the difference in wavelength as a correction coefficient C as shown in the following equation (3). λ The wavelength conversion formula for the calibration target is F B The spectrometer 40 to be calibrated is calibrated by adding

[0067] [Number 3] λ+C λ =C B0 +C B1 *P+C B2 *P 2 +C B3 *P 3 +C B4 *P 4 +C B5 *P 5 +C λ ···(3) λ: wavelength of the sensor with any pixel number C Bn : A coefficient specific to spectrometer B (n is 0 or a positive integer) P: Pixel number C λ : Correction coefficient based on wavelength difference

[0068] Equation (3) obtained by the above calibration is stored in the storage unit 23 of the control device 2. As a result, the spectral characteristics measured by the spectrometer B are corrected based on Equation (3) obtained by the above calibration, and the wavelength difference for each sensor with respect to the spectrometer A is canceled. As a result, the spectral characteristics after correction will match the spectral characteristics of the spectrometer A.

[0069] [Action and effect] As described above, the spectrometer calibration device according to this embodiment irradiates the spectrometer 40 to be calibrated with light having a known spectrum from the light source unit 3, and measures the light intensity of each of the sensors P0 to P1. n and wavelengths λ0 to λ n The spectrometer 40 to be calibrated is calibrated by calculating a wavelength conversion formula to be calibrated that defines the relationship between the above and the reference wavelength conversion formula, determining the difference between the calculated wavelength conversion formula to be calibrated and the reference wavelength conversion formula stored in the memory unit 23, and adding this difference as a correction coefficient to the wavelength conversion formula to be calibrated. Therefore, it is possible to cancel differences that occur in the spectral characteristics output between different spectrometers, and to obtain reproducibility of measurements between different spectrometers.

[0070] Furthermore, the spectrometer calibration device according to this embodiment calibrates the spectrometer 40 to be calibrated by calculating the wavelength difference for each sensor based on the reference wavelength conversion formula stored in the memory unit 23 and the wavelength conversion formula to be calibrated, and adding this difference as a correction coefficient to the wavelength conversion formula to be calibrated. This makes it possible to cancel out wavelength differences that occur for each sensor between different spectrometers, and to cancel out differences in the spectral characteristics output between different spectrometers.

[0071] The product inspection device of this embodiment is equipped with a spectrometer calibration device that can obtain measurement reproducibility between different spectrometers, so that the inspection accuracy in the inspection unit 21 does not vary between different spectrometers, and the inspection accuracy in the inspection unit 21 can be improved.

[0072] [Variations] In this embodiment, a fifth-order polynomial is used as the wavelength conversion formula, but it is not limited to fifth-order, and a polynomial of another order such as third-order may also be used.

[0073] In this embodiment, the calibration unit 24 calculates the wavelengths of the sensors P0 to P1 based on the reference wavelength conversion formula and the wavelength conversion formula to be calibrated. n The wavelength difference is calculated for each wavelength, and the difference in wavelength is used as the correction coefficient C λ In the above description, an example has been described in which the spectrometer 40 to be calibrated is calibrated by adding the following to the wavelength conversion formula to be calibrated. However, the present invention is not limited to this example, and the following calibration may also be performed.

[0074] That is, the calibration unit 24 calculates the difference in pixel number for each wavelength based on the reference wavelength conversion formula stored in the storage unit 23 and the wavelength conversion formula to be calibrated, and calculates the difference in pixel number as a correction coefficient C PN The spectrometer 40 to be calibrated may be calibrated by adding the above formula to the wavelength conversion formula to be calibrated.

[0075] Taking the calibration between the spectrometer A and the spectrometer B shown in FIG. 4 as an example, the control device 2 calculates the difference in pixel number as a correction coefficient C as shown in the following equation (4): PN The wavelength conversion formula for the calibration target is F B The spectrometer 40 to be calibrated is calibrated by adding

[0076] [Number 4] λ=C B0 +C B1 *(P+C PN )+C B2 *(P+C PN ) 2 +C B3 *(P+C PN ) 3 +C B4 *(P+C PN ) 4 +C B5 *(P+C PN ) 5 ···(4) λ: wavelength of the sensor with any pixel number C Bn: A coefficient specific to spectrometer B (n is 0 or a positive integer) P: Pixel number C PN : Correction coefficient based on the difference in pixel numbers

[0077] Equation (4) obtained by the above calibration is stored in the storage unit 23 of the control device 2. As a result, the spectral characteristics measured by the spectrometer B are corrected based on equation (4) obtained by the above calibration, and the difference in pixel number for each wavelength with respect to the spectrometer A is canceled. As a result, the spectral characteristics after correction will match the spectral characteristics of the spectrometer A.

[0078] In addition, if the wavelength conversion formula between the reference spectrometer A and the spectrometer B to be calibrated is unknown, you can set any wavelength for any pixel number to obtain the wavelength conversion formula F. C Create the wavelength conversion formula F C Based on this, the correction coefficient C n Calibration can be performed by determining

[0079] 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]

[0080] 1 Spectrometer 2. Control device 3 Light source section 4. Light detection unit 10. Item inspection equipment 21 Inspection Department 22 Calculation section 23 Memory section 24 Proofreading Department 30 light source 40 spectrometer 41 Spectroscopic element 42 Sensor Array W Goods C correction coefficient C λ Correction Factor C PN Correction Factor C n Correction Factor P Pixel number (sensor number)

Claims

1. A spectrometer calibration device that measures the light intensity of incident light for each wavelength by separating incident light into wavelengths using a spectroscopic element (41) and receiving the separated light with sensors arranged at positions corresponding to each wavelength, comprising: a light source unit (3) that irradiates a spectroscope (40, B) to be calibrated with light having a known spectrum; a storage unit (23) that stores a reference wavelength conversion formula that defines the relationship between each sensor and wavelength when light having the known spectrum is irradiated from the light source unit onto a reference spectrometer (40, A); a calculation unit (22) that calculates a wavelength conversion formula for the calibration target that defines the relationship between each sensor and wavelength by irradiating the spectrometer to be calibrated with light having the known spectrum from the light source unit; a calibration unit (24) that calibrates the spectrometer to be calibrated by calculating a difference between the reference wavelength conversion formula stored in the memory unit and the wavelength conversion formula to be calibrated, and adding the difference as a correction coefficient (C) to the wavelength conversion formula to be calibrated.

2. The calibration unit calculates a difference in wavelength for each sensor based on the reference wavelength conversion formula stored in the storage unit and the wavelength conversion formula to be calibrated, and calculates the difference as a correction coefficient (C λ 2. The apparatus for calibrating a spectrometer according to claim 1, wherein the spectrometer is calibrated by adding the wavelength conversion formula to the spectrometer to be calibrated as the wavelength conversion formula.

3. The calibration unit calculates the difference between the unique sensor number (P) for identifying each sensor for each wavelength based on the reference wavelength conversion formula stored in the storage unit and the wavelength conversion formula to be calibrated, and calculates the difference as a correction coefficient (C PN 2. The apparatus for calibrating a spectrometer according to claim 1, wherein the spectrometer is calibrated by adding the wavelength conversion formula to the spectrometer to be calibrated as the wavelength conversion formula.

4. The spectrometer calibration device according to any one of claims 1 to 3, and an inspection unit (21) that inspects the quality of the article (W) based on the spectroscopic characteristics measured by the spectrometer.

5. A method for calibrating a spectroscope in which incident light is resolved into wavelengths by a spectroscopic element (41), and the resolved light is received by sensors arranged at positions corresponding to the wavelengths, thereby measuring the light intensity of the incident light for each wavelength, comprising: a light source unit (3) that irradiates a spectroscope (40, B) to be calibrated with light having a known spectrum; a storage unit (23) that stores a reference wavelength conversion formula that defines the relationship between each sensor and wavelength when light having the known spectrum is irradiated from the light source unit onto a reference spectrometer (40, A); a calculation unit (22) that calculates a wavelength conversion formula for the calibration target that defines the relationship between each sensor and wavelength by irradiating the spectrometer to be calibrated with light having the known spectrum from the light source unit; a calibration unit (24) for calibrating the spectrometer to be calibrated, a calibration unit that calculates a difference between the reference wavelength conversion formula stored in the memory unit and the wavelength conversion formula of the calibration target, and adds the difference as a correction coefficient (C) to the wavelength conversion formula of the calibration target, thereby calibrating the spectrometer of the calibration target.

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