CN108318137B

CN108318137B - Spectrum measuring system, spectrum measuring device, optical measuring method and optical correction method

Info

Publication number: CN108318137B
Application number: CN201710032473.3A
Authority: CN
Inventors: 洪健翔; 林昇旺; 郑旭峯
Original assignee: OTO Photonics Inc
Current assignee: OTO Photonics Inc
Priority date: 2017-01-16
Filing date: 2017-01-16
Publication date: 2021-09-17
Anticipated expiration: 2037-01-16
Also published as: CN108318137A

Abstract

An optical calibration method is used for being executed by a spectrum measuring device with an optical input part. First, a plurality of narrow-band light beams are measured by the light input unit to obtain a plurality of narrow-band spectral impulse responses. And then, establishing a stray light database according to the narrow-frequency spectrum impulse responses. Generating a correction program based on the stray light database. Then, the spectral measurement device receives the spectral radiance standard light from the light input portion and enables the correction program to be enabled to measure the spectrum of the spectral radiance standard light to obtain the measured spectrum data. According to the measured spectrum data and the spectral radiation standard spectrum data, a correction coefficient program is generated, which can match the measured spectrum data with the spectral radiation standard spectrum data.

Description

Spectrum measuring system, spectrum measuring device, optical measuring method and optical correction method

Technical Field

The present invention relates to an optical measurement system (optical measurement system), an optical measurement apparatus and an optical calibration method, and more particularly, to a spectral measurement system, a spectral measurement method and an optical calibration method applied to the same.

Background

A spectrometer (spectrometer) is a common optical measurement device capable of analyzing Light to obtain a spectrum (spectrum), and many industries such as biotechnology, display panel manufacturers and Light Emitting Diode (LED) manufacturers currently have a plurality of spectrometers in production line. These spectrometers are calibrated for spectroradiometric flux (spectroradiometric calibration) using a spectroradiometric flux standard lamp, such as a halogen lamp, before the product or sample is first measured.

However, when each spectrometer receives the light from the standard lamp for calibration, stray light (stray light) is generated inside the spectrometer, and the stray light may adversely affect the measurement result to reduce the accuracy of the spectral radiant flux, thereby weakening the calibration effect. In addition, the stray light of the spectrometers is different from each other, so that the measurement results of the spectrometers measured on the same product or sample may have a significant and non-negligible difference from each other, resulting in inconsistent measurement results obtained by the spectrometers.

Disclosure of Invention

The invention provides an optical correction method, which improves the accuracy by reducing the influence of stray light on a measurement result.

The invention provides a spectrum measuring device, which adopts the optical correction method.

The invention provides a spectrum measuring system, which comprises a plurality of spectrum measuring devices and adopts the optical correction method to help the measuring results of the spectrum measuring devices to be consistent.

The invention provides a spectrum measuring method, which is suitable for the spectrum measuring device and the spectrum measuring system.

The optical calibration method provided by one embodiment of the invention is suitable for a spectrum measuring device, wherein the spectrum measuring device comprises an optical input part. In the optical calibration method, first, the spectrum measuring apparatus measures a plurality of narrow-band lights (narrow-band rays) through the optical input unit to obtain a plurality of narrow-band spectral impulse responses (impulse responses), respectively. Then, a stray light database is established according to the narrow-band spectral impulse responses, wherein the stray light database is provided with a spectrum measuring device and stray light information of a light input part of the spectrum measuring device. According to the stray light database, a correction program belonging to the spectrum measuring device is generated, wherein the correction program is used for correcting the stray light generated by the spectrum measuring device and the light input part thereof. In a state where the correction program is enabled, the spectrum measuring apparatus measures the spectral radiation standard light through the optical input portion to acquire the measured spectrum data processed by the correction program. Then, a calibration coefficient program (calibration coefficient program) belonging to the spectrum measuring device is generated according to the measured spectrum data and the spectral radiation standard spectrum data, wherein the calibration coefficient program enables the measured spectrum data to be matched with the spectral radiation standard spectrum data, and the spectral radiation standard spectrum data can be obtained by measuring the spectral radiation standard light by the standard spectrum measuring device.

The spectrum measuring system according to an embodiment of the present invention includes a first spectrum measuring device and an external processing device. The first spectrum measuring device generates a first correction program and a first correction coefficient program belonging to the first spectrum measuring device by the optical correction method. The first spectrum measuring device comprises a first optical module, a first circuit module and an external processing device. The first optical module includes a first optical input portion and a first spectrum generating device (first spectrum former). The first light input part is used for receiving a first to-be-detected light, and the first spectrum generating element is used for generating a plurality of first spectrum light beams from the first to-be-detected light. The first circuit module comprises a first light receiver and a first control unit. The first light receiver generates first spectrum data according to the first spectrum light beams. The first control unit is electrically connected with the first light receiver. The external processing device is coupled to the first control unit, wherein the first control unit or the external processing device can process the first spectrum data according to the first modification program and/or the first correction coefficient program.

The spectrum measuring device provided by one embodiment of the present invention generates a correction program and a correction coefficient program belonging to the spectrum measuring device by the optical correction method. The spectrum measuring device includes an optical module and a circuit module. The optical module is used for receiving a light to be detected and generating a plurality of spectral light beams from the light to be detected. The circuit module comprises an optical receiver and a control unit. The optical receiver is used for receiving the spectrum light beams to generate spectrum data. The control unit is electrically connected to the storage unit and the light receiver, wherein the control unit or the external processing device can process the spectrum data according to the correction program and/or the correction coefficient program.

The optical measurement method provided by one embodiment of the invention is suitable for the spectrum measurement device which is subjected to the optical correction method. In the optical measurement method, first, a spectrum measurement system is established, wherein the spectrum measurement system comprises a first spectrum measurement device. The first spectrum measuring device generates a first correction program and a first correction coefficient program belonging to the first spectrum measuring device by the optical correction method. A first to-be-detected light is measured by the first spectrum measuring device to obtain a first spectrum data. Processing the first spectrum data according to the first correction program and/or the first correction coefficient program in a state where the first correction program and/or the first correction coefficient program is enabled.

By using the correction program, the influence of stray light on the measurement result can be reduced or eliminated, so that the accuracy of the luminous flux of the spectrum measurement device is improved, and the measurement results of the spectrum measurement devices can be consistent.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following specific examples are described in detail with reference to the accompanying drawings.

Drawings

FIG. 1 is a block diagram of a spectrum measuring apparatus according to an embodiment of the present invention.

FIG. 2A is a flowchart illustrating an optical calibration method according to an embodiment of the invention.

Fig. 2B is a block diagram illustrating the spectrum measuring apparatus performing step S21 in fig. 2A.

Fig. 2C is a schematic diagram of a spectrum of one of the narrow-band lights in fig. 2B.

Fig. 2D is a stray light spectrum diagram of the narrow-band light in fig. 2C.

Fig. 2E is a schematic diagram of a spectral stray light distribution matrix created from the multiple channels of narrow-band light in fig. 2B.

Fig. 2F is a block diagram of the spectrum measuring apparatus performing step S24 in fig. 2A.

FIG. 3 is a block diagram of a spectrum measuring system according to an embodiment of the present invention.

Detailed Description

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.

Referring to fig. 1, a block diagram of a spectrum measuring apparatus 100 is shown. In the embodiment shown in fig. 1, the spectrum measuring apparatus 100 is capable of measuring a spectrum (optical spectrum) and includes an optical module 110 and a circuit module 120, and the spectrum measuring apparatus 100 may be a spectrometer, a spectrophotometer, an integrating sphere measuring system or a colorimeter. The optical module 110 can receive a light to be measured (measured light) L1 and generate a plurality of spectral light beams L2 from the light to be measured L1. The circuit module 120 can receive the spectrum light beams L2 and convert the spectrum light beams L2 into an electrical signal containing spectrum information (spectrum information).

The optical module 110 includes a light input portion 111 and a spectrum generating element 112, wherein the light input portion 111 and the spectrum generating element 112 are both disposed on a path (path) of the light L1 to be measured. The light input part 111 is used for receiving the light to be measured L1. furthermore, the light input part 111 may include a detachable optical component (including an integrating sphere, a cosine corrector, an optical coupler, an optical fiber, an optical filter and/or a lens group) and/or a non-detachable optical component (including a lens group, an optical fiber, an optical filter and/or a slit). In fig. 1, the optical input unit 111 is described as including an optical fiber 111 f.

The light to be measured L1 may be parallel light, a converged (focused) light beam (light beam), or a divergent light beam, whereas in the embodiment shown in fig. 1, the light to be measured L1 is a converged light beam. For example, the light L1 to be measured may be converged by at least one lens. Therefore, the light to be measured L1 may have a convergence angle (converging angle) L1 a. The light input section 111 has a light-receiving angle (light-receiving angle)111a smaller than the convergence angle L1a, as shown in fig. 1. However, in other embodiments, the light acceptance angle 111a may be equal to the convergence angle L1 a. Since the light-receiving angle 111a is smaller than or equal to the convergence angle L1a, a Numerical Aperture (NA) of the light-to-be-measured L1 is larger than or equal to a numerical aperture of the light-input section 111, so that a light-receiving area (not shown) and the light-receiving angle of the light-input section 111 can be completely irradiated by the light-to-be-measured L1. In addition, in the embodiment shown in fig. 1, the light to be measured L1 is a converged light beam, but in other embodiments, the light to be measured L1 may also be a parallel light or a plurality of rays (rays) directly emitted by a point light source (point light source), and is not limited to the light beam shown in fig. 1.

The light L1 to be measured passing through the light input unit 111 is incident on the spectrum generating device 112, and the spectrum generating device 112 can generate a plurality of spectrum light beams L2 from the light L1 to be measured, wherein the spectrum generating device 112 can include a collimating mirror, a focusing mirror, a beam splitter, a filter, a grating and/or a disperser to generate the spectrum light beams L2. The circuit module 120 includes an optical receiver 121, a storage unit 122 and a control unit 123. From the hardware aspect, the Circuit module 120 may be a Printed Circuit Board Assembly (PCBA), and the optical receiver 121, the storage unit 122 and the control unit 123 are mounted (mounted) on at least one Circuit Board. The control unit 123 is electrically connected to the optical receiver 121 and the storage unit 122 to control the optical receiver 121 and the storage unit 122, wherein the control unit 123 is, for example, a Programmable Logic Controller (PLC), a Microcontroller (MCU), a Microprocessor (μ P), or a Programmable Logic Device (PLD).

The optical receiver 121 can receive the spectrum light beams L2 generated by the spectrum generator 112 and convert the spectrum light beams L2 into electrical signals containing spectrum information, and the optical receiver 121 can be a one-dimensional or two-dimensional optical sensor array (optical sensor array), such as a photodiode array detector (photodiode array), a Charge-Coupled Device (CCD), or a Complementary Metal-Oxide-Semiconductor (CMOS). The optical receiver 121 can transmit the electrical signal to the control unit 123, so that the control unit 123 processes (processing) the spectrum information in the electrical signal to generate spectrum data (spectrum data), which is the measurement result of the light to be measured L1.

The storage unit 122 may be a non-volatile memory (non-volatile memory), such as a flash memory. Therefore, the storage unit 122 can be a Memory Card, such as a Secure Digital Memory Card (SD Card) or a Memory Stick (MS). The storage unit 122 can store a plurality of programs, and the control unit 123 can execute the programs in the storage unit 122 to control the operation of the optical receiver 121, wherein the control unit 123 can selectively enable (enabling) at least two of the programs. After the control unit 123 processes the spectrum information in the electrical signal, the control unit 123 can store the spectrum data in the storage unit 122. Therefore, the storage unit 122 can store not only the program but also the measurement result (i.e., spectral data) of the light to be measured L1.

The circuit module 120 may further include a transmission unit (transmission unit)124 electrically connected to the control unit 123. The transmission unit 124 may be a connection port (port), which may be a Serial port or a parallel port, such as a Universal Serial Bus (USB), RS-232-C Serial port or RS-485 Serial port. The transmission unit 124 may electrically connect to the external processing device 10, such as a notebook computer, a desktop computer, a tablet computer or an industrial computer (industrial computer), by using a transmission line (not shown). That is, the control unit 123 can be coupled to the external processing device 10 through the transmission unit 124 and the transmission line, so as to transmit the spectral data, i.e. the measurement result of the light to be measured L1, to the external processing device 10 through the transmission unit 124 and the transmission line, so that the external processing device 10 can perform subsequent processing on the spectral data.

In addition, the transmission unit 124 may also be a wireless transmission unit (wireless transmission unit), so that the control unit 123 can couple to the external processing device 10 through a wireless network (Wi-Fi) or a Bluetooth link (Bluetooth link) to transmit the spectral data to the external processing device 10 through the wireless network or the Bluetooth link, wherein the external processing device 10 may also be a cloud server. Therefore, the control unit 123 and the transmission unit 124 may establish a wired or wireless coupling, and the transmission unit 124 is not limited to be a wired transmission unit (wire transmission unit).

The programs stored in the storage unit 122 include a correction program and/or a correction coefficient program, and the correction program and the correction coefficient program can help to improve the spectral radiant flux accuracy of the spectrum measuring apparatus 100. The control unit 123 or the external processing device 10 can execute the correction program and the correction coefficient program, and can selectively enable and disable (disabling) at least one of the correction program and the correction coefficient program. In addition, the correction program and the correction coefficient program can be generated by executing the optical correction method described in fig. 2A, and the correction program and/or the correction coefficient program can also be stored in the external processing device 10 (such as a desktop computer or a cloud server) or an external storage medium (not shown), such as an optical disk or a flash drive, but not limited to be stored in the storage unit 122.

Referring to fig. 2A and 2B, in the optical calibration method shown in fig. 2A, first, step S21 is performed to enable the spectrum measuring apparatus 100 to measure a plurality of narrow-band lights L31 through the optical input portion 111 to obtain a plurality of narrow-band spectral impulse responses, respectively. The narrow-band light L31 is, for example, monochromatic light (monochromatic ray) emitted from the narrow-band light source 21, and the narrow-band light source 21 is, for example, a monochromator (monochromator) or tunable laser (tunable laser). In addition, the wavelength of each narrow-band light L31 is different, so that the wavelength of the narrow-band light L31 covers a certain range, such as 300 nanometers (nm) to 800 nm. Those skilled in the art can also determine how many nanometers of narrow-band light are emitted according to their needs, and the interval is smaller, and then the generated stray light database is more accurate; the larger the interval, the shorter the time taken by step S21.

The narrow-band light source 21 outputs only one narrow-band light L31 having a specific wavelength at a time, and the optical input section 111 receives the narrow-band lights L31 individually. That is, the narrow-band light L31 passes through the light input unit 111 one by one and enters the spectrum generating element 112, and all the narrow-band light L31 does not enter the spectrum generating element 112 at once. When the narrow-band lights L31 are respectively incident on the spectrum generating device 112, the spectrum generating device 112 can generate a plurality of spectrum light beams L32 incident on the light receiver 121 from the narrow-band lights L31 one by one.

The optical receiver 121 can receive the spectrum light beams L32 individually and convert the spectrum light beams L32 into a plurality of spectrum data in the form of electrical signals, wherein the spectrum data can be referred to as narrow-band spectrum impulse response. The control unit 123 may be used to process these narrow-band spectral impulse responses. In other words, each time the light input unit 111 receives one of the narrowband lights L31, the control unit 123 receives a corresponding narrowband spectral impulse response, which represents the spectrum of one of the narrowband lights L31. Thus, the spectrum measuring apparatus 100 can obtain these narrow-band spectral impulse responses.

In the embodiment shown in fig. 2B, the optical component 22B may be disposed between the narrow-band light source 21 and the light input portion 111, so that the narrow-band light L31 is incident on the light input portion 111 after passing through the optical component 22B, wherein the optical component 22B is optically coupled (optical coupling) with the light input portion 111. The optical element 22b may be a lens group, which may be composed of a plurality of lenses, and the optical element 22b can converge the narrow-band lights L31, such that each narrow-band light L31 has a convergence angle L3a, wherein the convergence angle L3a of each narrow-band light L31 is greater than or equal to the convergence angle 111 a. That is, the numerical aperture of each narrow-band light L31 is greater than or equal to the numerical aperture of the light input section 111. Since the convergence angle L3a is determined by the optical element 22b, the optical element 22b can also determine the numerical aperture of each narrow-band light L31. In the present embodiment, the optical element 22b can be used to change the light output mode of the narrow-band light source 21, so as to simulate the light output mode of the predetermined light source. In other embodiments, the optical assembly 22b may not be provided.

Referring to fig. 2A and 2B, after step S21, step S22 is performed to establish a stray light database having a spectrum measuring apparatus and stray light information of the light input portion thereof, wherein the stray light information includes stray light generated by the narrow-band light L31 in the light input portion 111 (including the optical fiber 111f) and stray light generated by the narrow-band light L31 after passing through the light input portion 111 until being received by the light receiver 121. In addition, the wavelength of the narrow-band light L31 covers a certain range (e.g., 300 nm to 800 nm), so the stray light information obviously only includes the stray light with the wavelength within the range, and does not include the stray light with the wavelength outside the range. In other embodiments, the wavelength range covered by the narrow-band light L31 can be adjusted by those skilled in the art according to their needs.

Step S22 can be executed by the spectrum measuring apparatus 100 or the external processing apparatus 10, i.e. a flare database can be created and stored in the spectrum measuring apparatus 100 or the external processing apparatus 10, so the control unit 123 or the external processing apparatus 10 can create a flare database according to the narrow-band spectral impulse responses, wherein the flare database can be created by using a spectral stray light distribution matrix (stray light distribution matrix) which can be APPLIED to the papers published by volume 45, No.6, application OPTICS, 2/20/2006: the contents of "Simple spectral gradient light correction method for array specrometer". Those skilled in the art can also adopt other methods for establishing the stray light database according to their needs.

In detail, please refer to fig. 2A and fig. 2C, wherein the spectrum 32j shown in fig. 2C is a spectrum of one of the narrow-band lights L31. In fig. 2C, the horizontal axis represents a pixel number (not shown) for each pixel (not shown) in the light receiver 121, and in the embodiment shown in fig. 2C, the number of pixels is 1024. The vertical axis is the relative intensity, which has a maximum value of 1.

In the light receiver 121 of the present embodiment, the 1024 pixels can be arranged in a line or an array, and each pixel substantially receives a spectral light beam with a specific wavelength (e.g., the spectral light beam L32 or the spectral light beam L2), so the wavelengths of the light received by the pixels are substantially different from each other. Therefore, the pixel number in fig. 2C can represent the wavelength of the spectral light beam. In addition, the spectrum 32j shown in fig. 2C (which is equivalent to one of the narrow-band spectral impulse responses) can be described by a Line-Spread Function (LSF). Since the spectrum 32j is generated by measuring a narrow-band light L31, a peak 32p representing the narrow-band light L31 appears in fig. 2C, which is located in a band IB 1. The peak 32p in the band IB1 can be regarded as a true signal of the narrow-band light L31, and the spectrum 32j outside the band IB1 can be regarded as a stray light signal.

Referring to fig. 2C and 2D, next, a stray light spectrum 32js is extracted from the spectrum 32 j. Since the peak 32p in the band IB1 can be regarded as a true signal of the narrow-band light L31, and the spectrum 32j outside the band IB1 can be regarded as a stray light signal, the peak 32p in the band IB1 is removed so that the relative intensity in the band IB1 becomes zero, and the remaining spectrum (as shown in fig. 2D) should theoretically contribute to the stray light. Next, the relative intensity of the spectrum 32j outside the band IB1 and the total relative intensity within the band IB1 are divided and normalized (normalization) to obtain the stray light spectrum 32 js. Then, according to the method disclosed in fig. 2C and fig. 2D, a plurality of stray light spectra are extracted from all the narrow-band spectral impulse responses, and a spectral stray light distribution matrix D shown in fig. 2E is established according to all the stray light spectra (including the stray light spectrum 32 js).

Referring to fig. 2E, the stray light spectrum distribution matrix D substantially includes a plurality of stray light spectra, and the stray light spectra are derived from different narrow-frequency light L31. Taking fig. 2E as an example, the spectral stray light distribution matrix D includes stray light spectra 32jc, 32js, and 32jx, and these stray light spectra 32jc, 32js, and 32jx are all derived from narrow-band light L31 having different wavelengths from each other.

In the stray light spectrum distribution matrix D, the relative intensity value of each pixel in the same stray light spectrum (e.g., stray light spectrum 32jc, 32js or 32jx) is sequentially filled in one row (column) of the matrix along the row direction X2, and the relative intensities of different narrow-band lights L31 received by the same pixel are sequentially filled in one row (row) of the matrix along the column direction X1. In this way, the spectral stray light distribution matrix D shown in fig. 2E is completed. In addition, since the peak 32p in the band IB1 is removed (see fig. 2D), a plurality of elements (elements) on the diagonal of the spectral stray light distribution matrix D are all zero, for example, the elements of the first row and the first column, the second row and the second column, and the third row and the third column are all zero.

The stray-light spectral distribution matrix D represents the influence of stray light on the spectral measurement apparatus 100, and satisfies the following mathematical expression (1).

Ym＝Yr+DYr.......................................(1)

In the formula (1), Ym and Yr are both column matrices (column matrices). Ym represents a spectrum actually measured by the spectrum measuring apparatus 100, for example, a spectrum obtained by measuring the light to be measured L1 or the narrow-band light L31, and Yr represents an ideal spectrum from which the influence of stray light is removed or reduced.

The formula (1) can be rewritten as the following formula (2).

Ym＝(I+D)Yr.................................(2)

In the mathematical formula (2), I is an identity matrix (identity matrix). Since Ym, D, and I are known and Yr is unknown, solving for Yr by solving equation (2) can yield an ideal spectrum in which the influence of stray light is removed or reduced.

There are various solutions to the mathematical formula (2) according to linear algebra (linear algebra). For example, the equation (2) can be used to obtain Yr by Gaussian elimination (Gaussian elimination algorithm), and the above APPLIED OPTICS (APPLIED OPTICS) paper mentioned on page 1114 can be used to obtain Yr by iterative algorithm (iterative algorithm). In this embodiment, an inverse matrix (inverse matrix) is used to obtain Yr.

Specifically, the mathematical formula (2) can be rewritten as the mathematical formula (3).

Ym＝(I+D)Yr＝AYr...........................(3)

In the formula (3), a is a coefficient matrix (coefficient matrix) and represents a stray light database, wherein the stray light database a satisfies the formula: a ═ I + D. That is, the stray light database a is obtained by adding the spectral stray light distribution matrix D and the unit matrix I, thereby completing step S22. In addition, since the diagonal elements of the spectral stray light distribution matrix D are all zero, the diagonal elements of the stray light database a are all 1.

Next, step S23 is performed to generate a correction program pertaining to the spectrum measuring apparatus 100 based on the stray light database. The correction program is used to correct the stray light generated by the spectrum measuring apparatus 100 and the light input portion 111 thereof, wherein the correction program generated according to the stray light database can be generated by the spectrum measuring apparatus 100 or the external processing apparatus 10, and in the embodiment, the correction program generated by the spectrum measuring apparatus 100 is taken as an example, wherein the correction program can be stored in the storage unit 122 of the spectrum measuring apparatus 100. However, in other embodiments, the correction program may be generated by the external processing device 10, and the correction program may also be stored in an external storage medium, such as an optical disc, a memory card, a hard disk, or a cloud hard disk. The correction routine may include a linear algebraic algorithm, such as an inverse matrix. In detail, the equation (3) can be derived as the following equation (4)

A-1Ym＝A-1AYr＝Yr...................(4)

In the formula (4), A-1 is an inverse matrix of A and is a correction program, so the correction program can be an inverse matrix of the coefficient matrix A (i.e. the stray light database). As is clear from the equation (4), the ideal spectrum Yr is obtained by multiplying the actually measured spectrum Ym by the inverse matrix a-1.

Based on the above, after the narrow-band light L31 is measured to obtain the narrow-band spectral impulse responses (e.g., spectrum 32j shown in fig. 2C), a stray light database can be built and a correction program can be generated according to the narrow-band spectral impulse responses. The correction program can be generated by linear algebra, such as an inverse matrix. When the control unit 123 enables the correction program, the influence of the stray light can be reduced or eliminated, thereby improving the accuracy of the spectrum measuring apparatus 100.

It should be noted that the above correction program is established based on stray light generated by an intrinsic optical path in the spectrum measuring apparatus 100, wherein the intrinsic optical path is an actual path along which light is transmitted from the light input portion 111 to the light receiver 121, and the intrinsic optical path is determined by an actual optical layout (physical optical layout) formed by the light input portion 111, the spectrum generator 112 and the light receiver 121. If the actual optical arrangement has slight variation, such as moving the spectrum generating element 112, the intrinsic optical path will also vary, so that the stray light generated by the intrinsic optical path will also change accordingly.

In other words, after the spectrum measuring apparatus 100 has been provided with the correction program, if any optical element (e.g., the optical fiber 111f) or the optical receiver 121 of the optical module 110 is moved, the inherent optical path in the spectrum measuring apparatus 100 will be changed, and the original stray light will be changed, so as to change the effect of the correction program, even the correction program cannot reduce the stray light. In addition, in practical situations, the intrinsic optical paths of any two spectrum measuring devices 100 are not the same, so the stray light of any two spectrum measuring devices 100 is also different, and the correction program of each spectrum measuring device 100 is different.

According to the above, the correction program is generated based on a plurality of narrow-band spectral impulse responses obtained by measuring a plurality of narrow-band lights L31, and the wavelength of these narrow-band lights L31 covers a certain range (e.g., 300 nanometers (nm) to 800 nm). Therefore, the correction program is basically suitable for the light to be measured L1 within the wavelength range covered by the narrow-band light L31. For the light L1 to be measured outside the wavelength range covered by the narrow-band light L31, the effect of effectively reducing the influence of stray light may be difficult to be exerted by the correction program. In other words, the correction program can mainly only eliminate or reduce the effect of the stray light in the specific wavelength range.

Referring to fig. 2A and 2F, next, step S24 and step S25 are sequentially performed to generate and store the correction coefficient program. In detail, in step S24, in a state that the correction program is enabled, the spectrum measuring apparatus 100 measures the spectral radiation standard light S1 through the light input portion 111 to obtain the measured spectrum data processed by the correction program, wherein the spectral radiation standard light S1 has a continuous spectrum (continuous spectrum) and can be emitted by a spectral radiation standard light source, and the spectral radiation standard light source is a light source having absolute spectral radiation flux information provided by a standard measuring mechanism, such as a halogen lamp or an incandescent lamp (incandescent lamp). After the spectral radiation standard light S1 is measured by the spectral measurement apparatus 100 under the condition that the control unit 123 enables the correction program stored in the storage unit 122, the spectral measurement apparatus 100 corrects the obtained measured spectral data according to the correction program. Therefore, the theoretically corrected measured spectrum data contains stray light signals caused by the inherent optical path in the spectrum measuring apparatus 100, which is very low, so that the spectrum measuring apparatus 100 can measure the spectrum of the standard light S1 of the split radiation with a low degree of influence of the stray light.

In steps S21 and S24, the spectrum measuring apparatus 100 can measure the spectrum of the narrow-band light L31 and the spectrum of the spectral radiance standard light S1 under the same light input condition. For example, the spectrum measuring apparatus 100 may measure the spectrum of the narrow-band light L31 and the spectrum of the spectral radiance standard light S1 by using the same optical input portion 111, that is, the spectrum of the spectral radiance standard light S1 and the spectrum of all or part of the narrow-band light L31 may be obtained by measuring the narrow-band light L31 and the spectral radiance standard light S1 passing through the optical fiber 111 f. Next, for example, the spectra of both the narrow-band light L31 and the spectral radiance standard light S1 may be measured at the same numerical aperture of the light input section 111, that is, the spectra of the narrow-band light L31 and the spectral radiance standard light S1 may be measured at the same light-receiving angle 111 a.

In the embodiment shown in fig. 2F, an optical assembly 22F may be disposed between the light input portion 111 and the standard light source 31 for split radiation, which is optically coupled to the light input portion 111, and the standard light for split radiation S1 is incident on the light input portion 111 after passing through the optical assembly 22F. The convergence angle L1a of the spectral radiant standard light S1 is greater than or equal to the light-receiving angle 111a, i.e., the numerical aperture of the spectral radiant standard light S1 is greater than or equal to the numerical aperture of the light-input section 111, so that the light-receiving region of the light-input section 111 can be fully irradiated with the spectral radiant standard light S1.

After the measurement spectrum data is obtained, step S25 is performed to generate a calibration coefficient program belonging to the spectrum measuring apparatus 100 according to the measurement spectrum data and the spectral radiance standard spectrum data, wherein the calibration coefficient program matches the measurement spectrum data with the spectral radiance standard spectrum data, and the spectral radiance standard spectrum data can be obtained by measuring the spectral radiance standard spectrum data by the standard spectrum measuring apparatus S1. Thereafter, the correction program and/or the correction coefficient program may be stored in the storage unit 122 of the spectrum measuring apparatus 100 or the external processing apparatus 10. It should be noted that the correction program and the calibration coefficient program are stored in the storage unit 122 of the spectrum measuring apparatus 100 to make the calculation more real-time.

More specifically, the standard spectrum measuring device has low stray light characteristics, and can effectively reduce the stray light by using hardware or software. In hardware, for example, the standard spectrum measuring device can use a temperature drift resistant optical system, an optical element with low thermal expansion coefficient, a high precision optical element with low tolerance, a stray light eliminating element and/or a filter to achieve low stray light characteristics. In software, for example, the standard spectrum measuring device can be another spectrum measuring device that is subjected to the calibration method of the present invention. That is, the standard spectrum measuring device may have generated the correction program thereof through the above steps S21 to S23, and the spectral radiation standard spectrum data is obtained by measuring the spectrum of the spectral radiation standard light S1 under the condition that the correction program of the standard spectrum measuring device is enabled. This also achieves low stray light characteristics.

It should be noted that the measured spectrum data and the spectral radiation standard spectrum data can seriously affect the effect of the correction coefficient program generated in step S25 if there is stray light. In this embodiment, the stray light of the measured spectrum data and the spectral radiation standard spectrum data is reduced by hardware and/or software. Then, in step S25, the external processing device 10 generates a calibration coefficient program pertaining to the spectrum measuring device 100 according to the measured spectrum data and the spectral radiance standard spectrum data. That is, the calibration coefficient program generated under the condition of low stray light can make the spectrum measuring apparatus 100 and the standard spectrum measuring apparatus obtain a similar measurement result when measuring the same light to be measured L1. In other embodiments, the calibration coefficient program may be generated by other electronic devices with computing capability, such as the control unit 123 of the spectrum measuring apparatus 100. The external processing device 10 may then store a calibration coefficient program pertaining to the spectrum measuring apparatus 100 in its storage unit 122.

Based on the above, in future applications, when the correction program and the correction coefficient program of the spectrum measuring apparatus 100 are both enabled, the spectrum data obtained by the spectrum measuring apparatus 100 measuring the light to be measured L1 through the light input section 111 (including the optical fiber 111f) is relatively similar to the spectrum data of the same light to be measured L1 measured by the standard spectrum measuring apparatus, even the spectrum data is substantially the same, wherein the wavelength of the light to be measured L1 can overlap with the wavelength range covered by the narrow-band light L31, so that the correction program can effectively exert the effect of reducing the influence of stray light. Thus, the correction program and the calibration coefficient program can reduce the difference in accuracy between the spectrum measuring apparatus 100 and the standard spectrum measuring apparatus, and make the measurement results of the two consistent.

In addition, in the optical calibration method described in FIG. 2A, since the narrow-band spectral impulse responses are measured through the optical input portion 111 including the optical fiber 111f, the stray light database includes the stray light signal generated by the optical input portion 111, so that if the correction program generated according to the calibration method of FIG. 2A is enabled, the correction program will automatically eliminate the stray light effect generated by the optical input portion 111. Therefore, when the spectrum measuring apparatus 100 with the enabled correction program and the enabled correction coefficient program measures the light to be measured L1, the spectrum measuring apparatus 100 needs to be equipped with the light input portion 111 (including the optical fiber 111f) and measure the light to be measured L1 through the light input portion 111, so that the correction program can correctly eliminate or reduce the influence of the stray light, thereby effectively reducing the difference in measurement result between the spectrum measuring apparatus 100 and the standard spectrum measuring apparatus.

The calibration coefficient can be a ratio function (ratio function) containing the ratio corresponding to each light wavelength. That is, the magnitude of the scaling function changes as the wavelength of light changes. The method for generating the calibration coefficient program can be to divide the spectral radiation standard spectrum data and the measured spectrum data to obtain the scaling function. When the spectrum measuring apparatus 100 with the calibration coefficient program and the correction program enabled performs measurement, the control unit 123 (or the external processing apparatus 10) may multiply the measured spectrum data with the scaling function. For example, the ratio corresponding to the wavelength of 500nm is 2, and the control unit 123 multiplies the value (e.g., the light intensity sensitivity) of the wavelength of 500nm in the spectrum data by 2.

In addition, the correction program and the calibration coefficient program can also make the measurement results of at least two spectrum measuring devices 100 consistent with the standard spectrum measuring device, and make these spectrum measuring devices 100 have the light flux accuracy close to or equal to that of the standard spectrum measuring device. That is, the plurality of spectrum measuring devices 100 can respectively perform the above optical calibration method to obtain the correction programs and the calibration coefficient programs, so that the measurement results of the spectrum measuring devices 100 can be consistent with each other, thereby reducing the machine difference between the spectrum measuring devices 100. In addition, since the stray light of any two spectrum measuring apparatuses 100 is actually different from each other, the respective correction programs and correction coefficient programs cannot be used with each other.

FIG. 3 is a block diagram of a spectrum measuring system according to an embodiment of the present invention. Referring to fig. 3, the spectrum measuring system 300 includes a plurality of (at least two) spectrum measuring devices and at least one external processing device 10, and each spectrum measuring device includes an optical module and a circuit module, wherein the optical modules respectively include a plurality of light input portions. In fig. 3, the spectrum measuring system 300 includes at least two spectrum measuring devices, a first spectrum measuring device 301 and a second spectrum measuring device 302.

The first spectrum measuring device 301 includes a first optical module 310 and a first circuit module 320. The first optical module 310 includes a first light input portion 311 and a first spectrum generating element 312. The first circuit module 320 includes a first optical receiver 321, a first storage unit 322, a first control unit 323, and a first transmission unit 324. The second spectrum measuring device 302 includes a second optical module 410 and a second circuit module 420. The second optical module 410 includes a second light input portion 411 and a second spectrum generating element 412. The second circuit module 420 includes a second optical receiver 421, a second storage unit 422, a second control unit 423, and a second transmission unit 424.

The first spectrum measuring device 301 and the second spectrum measuring device 302 can refer to the embodiments of the spectrum measuring device 100 of the previous embodiments, and are not described herein again. Therefore, the first spectrum measuring device 301 and the second spectrum measuring device 302 can perform the optical calibration method described in FIG. 2A to generate the first correction program and the first calibration coefficient program belonging to the first spectrum measuring device 301, and the second correction program and the second calibration coefficient program belonging to the second spectrum measuring device 302.

An embodiment of the present invention further provides an optical measurement method, which is suitable for the spectrum measurement system having undergone the calibration method described in fig. 2A, such as the spectrum measurement system 300 of fig. 3, wherein the calibration programs (e.g., the first and second calibration programs) and/or the calibration coefficient programs (e.g., the first and second calibration coefficient programs) can be stored in the first spectrum measurement device 301 and the second spectrum measurement device 302, the external processing device 10 (e.g., the cloud server) and/or an external storage medium, such as an optical disc or a flash drive. The correction program or/and the correction coefficient program has machine identification information related to the spectrum measuring device, and the machine identification information enables the spectrum measuring device to use the corresponding correction program or/and correction coefficient program, and the correction program or/and the correction coefficient program can only be used for correcting the spectrum data generated by the measurement of the spectrum measuring device.

Taking the spectrum measurement system of fig. 3 as an example, in the optical measurement method of the present embodiment, first, the first spectrum measurement device 301 and the second spectrum measurement device 302 are subjected to the optical calibration method described in the above embodiment to establish the spectrum measurement system 300. Then, the first spectrum measuring device 301 measures the first light to be measured L301 to obtain first spectrum data, and the second spectrum measuring device 302 measures the second light to be measured L302 to obtain second spectrum data, wherein the first spectrum measuring device 301 measures the first light to be measured L301 through the first light input portion 311, and the second spectrum measuring device 302 measures the second light to be measured L302 through the second light input portion 411.

Then, under the state that the first correction program and/or the first correction coefficient program are enabled, the first spectrum data is processed according to the first correction program and/or the first correction coefficient program, and the processed first spectrum data is less influenced by stray light and can be matched with the data measured by the standard spectrum measuring device. On the other hand, in the state that the second correction program and/or the second correction coefficient program is enabled, the second spectrum data is processed according to the second correction program and/or the second correction coefficient program, and the processed second spectrum data is less affected by stray light and can be matched with the data measured by the standard spectrum measuring device. That is, the modified first spectral data and the modified second spectral data are indirectly matched. However, in other embodiments, the first correction program and/or the first correction coefficient program, and the second correction program and/or the second correction coefficient program may be disabled according to different situations, and the first and second spectrum data may be processed under the circumstances. Therefore, the first and second correction programs and the first and second correction coefficient programs can be enabled or disabled according to the user's requirement.

Based on the above, under the condition that the first correction program, the second correction program, the first correction coefficient program and the second correction coefficient program are enabled, both the first spectrum measuring device 301 and the second spectrum measuring device 302 have the accuracy close to or equal to that of the standard spectrum measuring device. Thus, the first spectrum measuring device 301 and the second spectrum measuring device 302 can accurately measure the first light to be measured L301 and the second light to be measured L302 respectively under the condition of eliminating or reducing the influence of stray light. The effect is that the standard spectrum measuring device is used to measure the first light to be measured L301 and the second light to be measured L302 respectively. Those skilled in the art can also build a spectrum measuring system with more spectrum measuring devices according to their needs.

In summary, with the above correction program, the influence of the stray light on the measurement result can be reduced, so as to enable the spectrum measuring apparatus (such as the first spectrum measuring apparatus 301 or the second spectrum measuring apparatus 302) to generate the correction coefficient program with a lower degree of influence by the stray light. The difference of the measurement results among the plurality of spectrum measurement devices can be reduced, and the measurement results of the spectrum measurement devices can be consistent. In addition, the optical calibration method can ensure that the plurality of spectrum measuring devices have the accuracy close to or equal to that of a standard spectrum measuring device so as to establish a spectrum measuring system comprising a plurality of high-accuracy spectrum measuring devices. Thus, the spectrum measuring system can accurately measure the spectrum of a large number of products or samples at a time, thereby increasing the throughput (throughput) in spectrum measurement.

Although the present invention has been described with reference to the above embodiments, it should be understood that the invention is not limited to the above embodiments, and that various changes and modifications can be made by those skilled in the art without departing from the scope of the invention.

Claims

1. An optical calibration method is applied to a spectrum measuring device, and is characterized in that the spectrum measuring device comprises an optical input part, and the optical calibration method comprises the following steps:

the spectrum measuring device measures a plurality of narrow-band light beams through the light input part to respectively obtain a plurality of narrow-band spectral impulse responses;

establishing a stray light database according to the narrow-band spectral impulse responses, wherein the stray light database is provided with stray light information of the spectral measuring device and the light input part thereof;

generating a correction program belonging to the spectrum measuring device according to the stray light database, wherein the correction program is used for correcting the stray light generated by the spectrum measuring device and the light input part thereof;

in a state where the correction program is enabled, the spectrum measuring device measures a spectral radiation standard light through the light input portion to obtain a measured spectrum data processed by the correction program; and

generating a calibration coefficient program belonging to the spectrum measuring device according to the measured spectrum data and a spectral radiation standard spectrum data, wherein the calibration coefficient program enables the measured spectrum data to be matched with the spectral radiation standard spectrum data, and the spectral radiation standard spectrum data is obtained by measuring the spectral radiation standard light by a standard spectrum measuring device.

2. The optical calibration method of claim 1, wherein the step of creating the stray light database is generated by the spectral measurement device or an external processing device according to the narrow-band spectral impulse responses.

3. The optical calibration method according to claim 1, wherein the correction program generated according to the stray light database is generated by the spectrum measurement device or an external processing device.

4. The optical calibration method according to claim 1, wherein the spectrum measuring device measures the spectrum of the standard light of the split-beam radiation through the light input portion in a state where the calibration program is enabled to obtain the measured spectrum data processed by the calibration program, the calibration program being executed by the spectrum measuring device or an external processing device.

5. The optical calibration method of claim 1, wherein the spectral data obtained by measuring the spectrum of the spectral standard light by the standard spectrum measuring device comprises:

the standard spectrum measuring device measures a plurality of first narrow-band light beams through the light input part of the standard spectrum measuring device so as to respectively obtain a plurality of first narrow-band spectral impulse responses;

establishing a first stray light database according to the first narrow-band spectral impulse responses, wherein the first stray light database is provided with stray light information of the standard spectrum measuring device and the light input part of the standard spectrum measuring device;

generating a first correction program according to the first stray light database, wherein the first correction program is used for correcting the stray light generated by the standard spectrum measuring device and the light input part thereof; and

in a state where the first correction program is enabled, the standard spectrum measuring device measures the spectrum of the spectral radiation standard light through the light input portion thereof to obtain the spectral radiation standard spectrum data processed by the first correction program.

6. The optical correction method of claim 1, further comprising:

a second spectrum measuring device measures a plurality of second narrow-band light beams through the light input part of the second spectrum measuring device so as to respectively obtain a plurality of second narrow-band spectral impulse responses;

establishing a second stray light database according to the second narrow-band spectral impulse responses, wherein the second stray light database is provided with stray light information of the second spectrum measuring device and the light input part of the second spectrum measuring device;

generating a second correction program according to the second stray light database, wherein the second correction program is used for correcting the stray light generated by the second spectrum measuring device and the light input part thereof;

in a state where the second correction program is enabled, the second spectrum measuring device measures the spectrum of the spectral radiance standard light through the light input portion thereof to obtain a second measured spectrum data processed by the second correction program; and

generating a second calibration coefficient program according to the second measurement spectrum data and the standard spectrum data of the spectral radiation, wherein the second calibration coefficient program matches the measurement spectrum data with the standard spectrum data of the spectral radiation obtained by measuring the standard spectrum data of the spectral radiation by the standard spectrum measuring device.

7. The optical correction method of claim 1, wherein the numerical aperture of each of the narrow-band lights is greater than or equal to the numerical aperture of the light input portion, and the numerical aperture of the standard light of the split radiant is greater than or equal to the numerical aperture of the light input portion.

8. The optical calibration method of claim 1, wherein the narrow-band lights are emitted from a narrow-band light source, and an optical element is disposed between the narrow-band light source and the light input portion, the narrow-band lights are incident on the light input portion from the narrow-band light source through the optical element, and the optical element is used for determining a numerical aperture of each of the narrow-band lights.

9. The optical correction method of claim 1, further comprising:

storing the correction program or/and the calibration coefficient program in a non-volatile memory in the spectrum measuring apparatus.

10. The optical correction method of claim 1, further comprising:

storing the correction program or/and the correction coefficient program in an external storage medium, wherein the correction program or/and the correction coefficient program has a machine identification information related to the spectrum measuring device, and the machine identification information is used to enable the correction program or/and the correction coefficient program to only correct the spectrum data generated by the measurement of the spectrum measuring device.

11. A spectral measurement system, comprising:

a first spectrum measuring apparatus, which generates a first correction program and a first correction coefficient program belonging to the first spectrum measuring apparatus by the optical correction method of claim 1, the first spectrum measuring apparatus comprising:

a first optical module including a first light input part for receiving a first to-be-detected light and a first spectrum generating element for generating a plurality of first spectrum light beams from the first to-be-detected light;

a first circuit module, comprising:

a first light receiver for generating a first spectrum data according to the first spectrum beams;

a first control unit electrically connected to the first light receiver; and

an external processing device coupled to the first control unit, wherein the first control unit or an external processing device can process the first spectrum data according to the first correction program and/or the first correction coefficient program.

12. The spectral measurement system of claim 11, further comprising:

a second spectrum measuring apparatus, which generates a second correction program and a second correction coefficient program belonging to the second spectrum measuring apparatus by the optical correction method as claimed in claim 1, the second spectrum measuring apparatus comprising:

a second optical module including a second light input portion for receiving a second light to be measured and a second spectrum generating element for generating a plurality of second spectrum light beams from the second light to be measured;

a second circuit module, comprising:

a second light receiver for generating a second spectrum data according to the second spectrum light beams; and

a second control unit electrically connected to the second optical receiver and coupled to the external processing device, wherein the second control unit or the external processing device can process the second spectrum data according to the second correction program and/or the second correction coefficient program.

13. The system of claim 11, wherein the first circuit module further comprises:

a storage unit electrically connected to the control unit and storing the first correction program and/or the first correction coefficient program.

14. The system of claim 13, wherein the storage unit further stores information on whether the first correction program and/or the first calibration coefficient program is enabled or not.

15. A spectrum measuring apparatus, which generates a correction program and a correction coefficient program belonging to the spectrum measuring apparatus by the optical correction method as claimed in claim 1, the spectrum measuring apparatus comprising:

the optical module is used for receiving a light to be detected and generating a plurality of spectral light beams from the light to be detected;

a circuit module, comprising:

a light receiver for receiving the spectrum light beams to generate a spectrum data; and

a control unit electrically connected to the light receiver, wherein the control unit or an external processing device can process the spectrum data according to the correction program and/or the correction coefficient program.

16. The apparatus of claim 15, wherein the circuit module further comprises:

a storage unit electrically connected to the control unit and storing the correction program and/or the correction coefficient program.

17. An optical measurement method applied to a spectral measurement apparatus subjected to the optical calibration method of claim 1, the optical measurement method comprising:

establishing a spectrum measuring system, wherein the spectrum measuring system comprises a first spectrum measuring device, and the first spectrum measuring device is subjected to the optical calibration method of claim 1 to generate a first correction program and a first calibration coefficient program belonging to the first spectrum measuring device;

measuring a first to-be-measured light by the first spectrum measuring device to obtain a first spectrum data; and

processing the first spectrum data according to the first correction program and/or the first correction coefficient program in a state that the first correction program and/or the first correction coefficient program are enabled.

18. An optical measurement method according to claim 17, further comprising:

the first correction program and/or the first correction coefficient program are disabled or enabled.

19. The optical measurement method of claim 17, wherein the step of establishing the optical spectrum measurement system further comprises a second optical spectrum measurement device, the second optical spectrum measurement device being subjected to the optical calibration method of claim 1 to generate a second correction program and a second correction coefficient program belonging to the second optical spectrum measurement device, the optical measurement method further comprising:

measuring a second light to be measured by the second spectrum measuring device to obtain a second spectrum data; and

processing the second spectrum data according to the second correction program and/or the second correction coefficient program in a state where the second correction program and/or the second correction coefficient program are enabled.

20. The optical measurement method of claim 17, wherein the step of establishing the optical spectrum measurement system comprises generating the first correction program and the first calibration coefficient program under a condition that the first optical spectrum measurement device has a first light input portion, and the step of measuring the first light to be measured by the first optical spectrum measurement device comprises measuring the first light to be measured through the first light input portion.