CN107490433A - A kind of spectrum calibration method and grating spectrograph based on grating spectrograph - Google Patents

Abstract

Spectrum calibration method and grating spectrograph of the invention based on grating spectrograph,Grating spectrometer architecture can include element spectral line lamp,Collimating mirror,Angular displacement platform,Raster on the angular displacement platform,Focus lamp and imaging device,The raster is irradiated to the first incidence angle after collimating mirror collimation by the optical signal that the element spectral line lamp is sent,By the diffracted light signals of the raster diffraction imaging device is imaged in via focus lamp,According to grating equation,Pass through angular displacement platform rotating shutter,Cause the rotation of grating planar normal,Change the first incidence angle i and diffraction angle,So as to change the wave-length coverage on detector pixel,It can realize that grating wavelength scans based on the principle,And then realize wide scope,High-resolution spectral measurement,Required professional auxiliary equipment is few,It is easy to operate,Spectral calibration precision is high,It is fast to calibrate speed,It is easy to maintain.

Description

A spectral calibration method based on grating spectrometer and grating spectrometer

technical field

The invention relates to the field of spectral analysis instruments, in particular to a wide-band range and high-precision spectral scanning calibration method suitable for grating spectrometers.

Background technique

The grating spectrum analyzer mainly disperses the incident light signal according to the wavelength through a dispersive device such as a grating, so as to obtain the spectral distribution of the signal to be measured on the image plane of the detector. In order to balance the contradiction between spectral detection range and spectral resolution, according to the actual application, high spectral resolution or wide spectral detection range is selected by switching the grating, but this method cannot obtain high resolution and wide spectral range at the same time. At present, a wide spectral range and high spectral resolution are obtained at the same time through raster scanning. The scanning mechanism drives the grating to rotate to change the angle between the incident light on the grating and the normal line to achieve spectral scanning, thereby changing the wavelength band on the detector almost continuously. Range, the contradiction between resolution and spectral range is transformed into the contradiction between resolution and scanning detection time, and the detection time is sacrificed to obtain a wide spectral range under the condition of certain spectral resolution.

In a traditional monochromator, only a single-point detector is used, and a single acquisition only detects a single wavelength during the scanning process, resulting in a too slow scanning speed. Therefore, a linear array or an area array detector is used instead of a single-point detector, so that a single acquisition can simultaneously measure multi-wavelength spectra, thereby realizing fast scanning detection. For a specific pixel on the detector, during the raster scanning process, the angle between the incident ray and the diffracted ray of the corresponding grating remains unchanged, but the angle between the incident ray and the diffracted ray corresponding to different pixels is different, so As a result, different pixels have different changing rules with the grating rotation angle, which increases the difficulty of achieving accurate spectral calibration.

Currently commonly used raster scanning mechanisms include sinusoidal scanning mechanisms and angular displacement platform scanning mechanisms. Since the rotation angle of the grating has a sinusoidal relationship with the wavelength conversion on the detector, using a sinusoidal mechanism driven by a stepping motor can make the wavelength variation on the detector pixel change linearly with the stepping motor to simplify the spectral calibration process . Since the wavelength variation relationship on different pixels varies with the stepping amount, this scanning mechanism is mostly used in monochromators, that is, it is used with a single-point detector, so the scanning speed is slow. When the high-precision angular displacement platform is used to drive the grating to rotate and cooperate with the linear array or area array detector to realize fast scanning, due to the non-linearity of the grating rotation angle and wavelength change, it is necessary to use a special scanning calibration algorithm for scanning calibration to obtain higher Therefore, it is urgent to provide a method to solve this technical problem.

Contents of the invention

In view of this, an embodiment of the present invention provides a grating spectrometer-based spectrum calibration method and a grating spectrometer.

In the first aspect, the spectral calibration method based on a grating spectrometer provided by the present invention, the method includes:

Select the characteristic spectral line light source, adjust the angle of the angular displacement platform so that at least the first characteristic spectral line and the second characteristic spectral line are on the image plane of the detector, record the first rotational angle and the first characteristic spectral line and the second characteristic spectral line of the current angular displacement platform The position of the two characteristic spectral lines;

Adjust the rotation of the angular displacement platform so that the second characteristic spectral line is transferred to the position of the first characteristic spectral line when the rotation angle is the first rotation angle, record the current second rotation angle of the angular displacement platform, according to the first the angle of rotation and said second angle of rotation determine a difference in angle of rotation;

Determine the first grating incidence angle corresponding to all pixels when the angle of rotation of the angular displacement platform is the first angle according to the angle difference, the wavelength of the first characteristic spectral line, and the grating equation;

Determine the current wavelength values corresponding to all the pixels according to the first characteristic spectral line and the second characteristic spectral line at the first rotation angle and the preset relationship;

Determine the first grating diffraction angle corresponding to the pixel point according to the wavelength of the characteristic spectral line corresponding to any pixel and the first grating incident angle and the grating equation;

The angle relationship between the incident ray and the diffracted ray on the grating is determined according to the first grating incident angle and the first grating diffraction angle, so as to complete the calibration of the initial image plane.

Optionally, when performing low-band direction calibration, the method further includes:

determining a corresponding third wavelength value on the Sth pixel according to the preset relationship;

Rotate the angular displacement platform so that the Eth pixel corresponds to the third wavelength value to complete wavelength scanning, the third wavelength value determined according to the angle relationship and the grating incident light and diffraction on the Eth pixel The included angle of light determines the incident angle of the second grating;

Determine the second rotation angle of the current angular displacement platform according to the variation of the grating rotation angle equal to the variation of the grating incident angle;

Combining the angle between the grating incident ray and the diffracted ray on the Eth pixel, the second grating incident angle and the second rotation angle to determine the current second grating diffraction angle;

determining the current fourth wavelength value on the Eth pixel according to the second grating diffraction angle and the grating equation;

Determine the wavelength values corresponding to all current pixels according to the linear distribution of wavelengths and the angle relationship, so as to complete the wavelength calibration at the second corner, wherein the effective working pixel range is from the S+1th pixel to the Eth image between yuan.

Optionally, when performing long-wave direction calibration, the method further includes:

determining the corresponding fifth wavelength value on the E+1th pixel according to the preset relationship;

Rotate the angular displacement platform so that the S pixel corresponds to the fifth wavelength value to complete wavelength scanning, the fifth wavelength value determined according to the angle relationship and the grating incident light and diffracted light on the S pixel The included angle determines the incident angle of the third grating;

Determine the third rotation angle of the current angular displacement platform according to the variation of the grating rotation angle equal to the variation of the grating incident angle;

Combining the angle between the grating incident ray and the diffracted ray on the Sth pixel, the third grating incident angle and the third rotation angle to determine the current third grating diffraction angle;

determining the current sixth wavelength value on the Sth pixel according to the third grating diffraction angle and the grating equation;

Determine the wavelength values corresponding to all current pixels according to the linear distribution of wavelengths and the angle relationship, so as to complete the wavelength calibration at the third corner, where the effective working pixel range is from the S+1th pixel to the Eth image between yuan.

Optionally, after determining the angle relationship between the incident ray and the diffracted ray on the grating according to the first grating incident angle and the first grating diffraction angle, the method further includes:

The wavelength accuracy of the calibration results is used for error calibration.

Optionally, performing error calibration on the wavelength accuracy of the calibration results includes:

Polynomial fitting is performed on the calibration results to approximate the wavelength calibration errors of all pixels in the scanning process, so as to correct the calibration results.

Optionally, the preset relationship is:

Wherein, said λ ₁ is the wavelength value of the first characteristic spectral line, λ ₂ is the wavelength value of the second characteristic spectral line, n ₁ is the pixel position where the peak value of the first characteristic spectral line is, and n ₂ is the second characteristic spectral line The pixel position where the peak is located, λ _n is the wavelength value corresponding to the nth pixel.

Optionally, the grating equation is:

d(sinα+sinβ)=mλ,

Among them, d is the slit spacing, that is, the grating constant, m is an integer, and the value is 0, ±1, ±2,..., α is the incident angle of the grating, β is the diffraction angle of the grating, and λ is the wavelength of the corresponding spectral signal value.

In the second aspect, the grating spectrometer provided by the present invention is applied with the above-mentioned method, comprising an elemental line lamp, a collimating mirror, an angular displacement platform, a scanning grating on the angular displacement platform, a focusing mirror and an imaging device, by the The optical signal emitted by the elemental line lamp is collimated by the collimating mirror and irradiates the scanning grating at a first incident angle, and the diffracted optical signal diffracted by the scanning grating is imaged on the imaging device through the focusing mirror.

Optionally, the elemental line lamp includes one of a mercury lamp, a deuterium lamp, a tungsten lamp or a cadmium lamp.

Optionally, the imaging device is a line array detector or an area array detector.

It can be seen from the above technical solutions that the embodiments of the present invention have the following advantages:

The present invention is based on the spectral calibration method of the grating spectrometer and the grating spectrometer. It only needs to use at least two characteristic spectral lines for one calibration, and no other hardware parameters of the spectral dispersion system are required except for the grating constant. Accurate spectral scanning calibration can accurately determine the relationship between the angle of the angular displacement platform and the range of the image plane of the detector, requires less professional auxiliary equipment, is easy to operate, has high spectral calibration accuracy, fast calibration speed, and is easy to maintain.

Description of drawings

Fig. 1 is the flowchart of a kind of spectral calibration method provided in the embodiment of the present invention;

Fig. 2 is a flowchart of another spectral calibration method provided in the embodiment of the present invention;

Fig. 3a is a schematic diagram of an initial calibration data acquisition method in an embodiment of the present invention;

Fig. 3b is a schematic diagram of an initial calibration data acquisition method in an embodiment of the present invention;

4 is a schematic diagram of a wavelength iterative calibration method in an embodiment of the present invention;

5 is a schematic diagram of the system calibration error polynomial fitting result after wavelength iterative calibration in an embodiment of the present invention;

Fig. 6 is a structural diagram of a raster scanning spectrometer provided in an embodiment of the present invention.

In the figure: 11 linear array or area array detector; 12 focusing mirror; 13 scanning grating; 14 collimating mirror; 15 element spectral line lamp; i grating incident angle; θ grating diffraction angle.

detailed description

In order to enable those skilled in the art to better understand the solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is an embodiment of a part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

The terms "first", "second", "third, fourth", etc. (if any) in the description and claims of the present invention and the above drawings are used to distinguish similar objects and not necessarily to describe A particular order or sequence. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

Glossary:

A grating spectrometer is a scientific instrument that decomposes light with complex components into spectral lines. Through the capture of light information by the spectrometer, the development of photographic negatives, or the display and analysis of computerized automatic display numerical instruments, it is possible to determine what elements are contained in the item. Grating spectrometers are widely used in color measurement, concentration measurement of chemical components or radiometric analysis, film thickness measurement, gas composition analysis and other fields.

Pixel, also known as pixel or pixel point. The image unit (picture element). It is the smallest unit that makes up a digital image. In remote sensing data acquisition, such as scanning imaging, it is the smallest unit for the sensor to scan and sample the ground scene; in digital image processing, it is the sampling point when scanning and digitizing analog images.

The characteristic spectral line is a one-to-one correspondence between the bright line of the spectrum emitted by a substance at high temperature and the dark line of its absorption spectrum at low temperature, so the bright line spectrum and absorption spectrum of an element are the characteristics of the element. The bright line of the spectrum emitted by a substance at high temperature corresponds to the position of the dark line of its absorption spectrum at low temperature, so the bright line spectrum and absorption spectrum of an element are the characteristics of the element, called characteristic spectral lines.

Element lamp: Each element has its fixed excitation wavelength. The element lamp is a lamp that can excite a fixed wavelength. It can provide the wavelength of one or more elements, which is used to detect the absorption of a certain wavelength by the sample, so as to determine the The content of the element in the sample.

Since the wavelength variation relationship on different pixels varies with the stepping amount, this scanning mechanism is mostly used in monochromators, that is, it is used with a single-point detector, so the scanning speed is slow. When the high-precision angular displacement platform is used to drive the grating to rotate and cooperate with the linear array or area array detector to realize fast scanning, due to the non-linearity of the grating rotation angle and wavelength change, it is necessary to use a special scanning calibration algorithm for scanning calibration to obtain higher calibration accuracy, the present invention can solve this technical problem.

As shown in FIG. 1, an embodiment of the present invention provides a spectral calibration method based on a grating spectrometer. In this embodiment, the grating spectrometer structure may include an elemental line lamp, a collimating mirror, an angular displacement platform, and a The scanning grating, focusing mirror and imaging device on the angular displacement platform, the optical signal emitted by the elemental line lamp is collimated by the collimating mirror and then irradiates the scanning grating at the first incident angle, and passes through the scanning The diffracted light signal diffracted by the grating is imaged on the imaging device through the focusing mirror. According to the grating equation, the grating is rotated through the angular displacement platform, resulting in the rotation of the grating plane normal, changing the first incident angle i and the diffraction angle θ, thereby changing the detector The wavelength range on the pixel, based on this principle, can realize grating wavelength scanning, and then realize wide-range and high-resolution spectral measurement. The method includes:

S101. Select the characteristic spectral line light source, adjust the angle of the angular displacement platform so that at least the first characteristic spectral line and the second characteristic spectral line are on the image plane of the detector, and record the first rotational angle and the first characteristic spectral line of the angular displacement platform currently and the position of the second characteristic spectral line;

S102. Adjust the rotation of the angular displacement platform so that the second characteristic spectral line is transferred to the position of the first characteristic spectral line when the rotation angle is the first rotation angle, and record the current second rotation angle of the angular displacement platform, according to the the first rotation angle and said second rotation angle determine a rotation angle difference;

S103. Determine the first grating incident angle corresponding to all pixels when the rotation angle of the angular displacement platform is the first rotation angle according to the rotation angle difference, the wavelength of the first characteristic spectral line, and the grating equation;

Specifically, the grating equation is:

d(sinα+sinβ)=mλ,

Among them, d is the slit spacing, that is, the grating constant, m is an integer, and the value is 0, ±1, ±2,..., α is the incident angle of the grating, β is the diffraction angle of the grating, and λ is the wavelength of the corresponding spectral signal value.

S104. Determine the current wavelength values corresponding to all the pixels according to the first characteristic spectral line and the second characteristic spectral line at the first rotation angle and the preset relationship;

Specifically, the preset relationship is:

Wherein, said λ ₁ is the wavelength value of the first characteristic spectral line, λ ₂ is the wavelength value of the second characteristic spectral line, n ₁ is the pixel position where the peak value of the first characteristic spectral line is, and n ₂ is the second characteristic spectral line The pixel position where the peak is located, λ _n is the wavelength value corresponding to the nth pixel.

S105. Determine the first grating diffraction angle corresponding to the pixel point according to the wavelength of the characteristic spectral line corresponding to any pixel, the first grating incident angle and the grating equation;

S106. Determine the angle relationship between the incident ray and the diffracted ray on the grating according to the first grating incident angle and the first grating diffraction angle, so as to complete the calibration of the initial image plane.

The spectral calibration method based on the grating spectrometer in the present invention only needs to use at least two characteristic spectral lines for one calibration, and does not need other hardware parameters of the spectral dispersion system except the grating constant, and can complete the high-precision spectral scanning of the spectrometer in a wide band range Calibration, to accurately determine the relationship between the angle of the angular displacement platform and the range of the image plane of the detector, requires less professional auxiliary equipment, easy operation, high spectral calibration accuracy, fast calibration speed, and easy maintenance.

Optionally, when performing low-band direction calibration, the method further includes:

determining a corresponding third wavelength value on the Sth pixel according to the preset relationship;

Rotate the angular displacement platform so that the Eth pixel corresponds to the third wavelength value to complete wavelength scanning, the third wavelength value determined according to the angle relationship and the grating incident light and diffraction on the Eth pixel The included angle of light determines the incident angle of the second grating;

Determine the second rotation angle of the current angular displacement platform according to the variation of the grating rotation angle equal to the variation of the grating incident angle;

Combining the angle between the grating incident ray and the diffracted ray on the Eth pixel, the second grating incident angle and the second rotation angle to determine the current second grating diffraction angle;

Determine the fourth wavelength value corresponding to the current Eth pixel according to the second grating diffraction angle and the grating equation;

Determine the wavelength values corresponding to all current pixels according to the linear distribution of wavelengths and the angle relationship, so as to complete the wavelength calibration at the second corner, wherein the effective working pixel range is from the S+1th pixel to the Eth image between yuan.

Optionally, when performing long-wave direction calibration, the method further includes:

determining the corresponding fifth wavelength value on the E+1th pixel according to the preset relationship;

Rotate the angular displacement platform so that the Sth pixel corresponds to the fifth wavelength value to complete wavelength scanning, the fifth wavelength value determined according to the angle relationship and the grating incident light and diffraction on the Sth pixel The included angle of light determines the incident angle of the third grating;

Determine the third rotation angle of the current angular displacement platform according to the variation of the grating rotation angle equal to the variation of the grating incident angle;

Combining the angle between the grating incident ray and the diffracted ray on the Sth pixel, the third grating incident angle and the third rotation angle to determine the current third grating diffraction angle;

Determine the sixth wavelength value corresponding to the current Sth pixel according to the third grating diffraction angle and the grating equation;

Determine the wavelength values corresponding to all current pixels according to the linear distribution of wavelengths and the angle relationship, so as to complete the wavelength calibration at the third corner, where the effective working pixel range is from the S+1th pixel to the Eth image between yuan.

After determining the angle relationship between the incident ray and the diffracted ray on the grating according to the first grating incident angle and the first grating diffraction angle, the method further includes:

S107 , performing error calibration on the wavelength accuracy of the calibration result.

Specifically, the error calibration of the wavelength accuracy of the calibration results includes:

Polynomial fitting is performed on the calibration results to approximate the wavelength calibration errors of all pixels in the scanning process, so as to correct the calibration results.

As shown in Figure 5, due to the system positioning error of the angular displacement platform during the scanning process, there is a wavelength accuracy error during the scanning process. A series of characteristic spectral lines can be used to calibrate the system wavelength accuracy error, and the calibration results Perform polynomial fitting to approximate the wavelength calibration error on each pixel during the scanning process, thereby correcting the scanning calibration results to improve the calibration wavelength accuracy.

In the wavelength scanning optical path, the angle between the grating incident light and diffracted light corresponding to the same pixel is always kept constant, the angle of the fixed-angle displacement platform is fixed, and the incident angle of the grating corresponding to each pixel of the detector is the same. In the small waveband range, the grating Dispersion linearity is better. Based on the above-mentioned characteristics of raster scanning, the present invention performs segmented linear calibration on raster scanning, and the spectral calibration method based on grating spectrometer provided by the present invention is specifically introduced below:

S201. Select the characteristic spectral line light source, adjust the angle of the angular displacement platform, so that at least two characteristic spectral lines (λ2, λ3) are on the image plane of the detector, and record the angular displacement platform rotation angle ψ and the positions of the two characteristic spectral lines at this time;

S202. Adjust the angle of rotation of the angular displacement platform so that the characteristic spectral line λ3 is transferred to the position of the characteristic spectral line λ2 when the rotation angle is ψ, and record the rotation angle ψ' of the angular displacement platform at this time;

S203, according to the angle difference Δ _ψ between the angles ψ and ψ', calculate the incident angle of the grating at the position of the characteristic spectral line λ2 when the angle of rotation of the angular displacement platform is ψ;

S204. When the angle of rotation of the angular displacement platform is ψ, complete the wavelength calibration of the effective range ( _ns -n _e ) of the frame pixel at the position of the detector according to the characteristic spectral lines λ2 and λ3;

S205. Calculate the angle between the grating incident light and diffracted light on the ns and ne pixels;

S206. Calculate the wavelength on the n _s -1 pixel, then calculate the angle of the angular displacement platform when the wavelength is transferred to the n _e pixel, and then calculate the wavelength on the n _s pixel at this time, then complete a set of wavelength calibration , successively recursively deduce the wavelength calibration in this direction;

S207. Calculate the wavelength on the n _e +1 pixel, then calculate the angle of the angular displacement platform when the wavelength is transferred to the n _s pixel, and then calculate the wavelength on the n _e pixel at this time, then complete a set of wavelength calibration , and in turn recursively deduce the wavelength scaling in this direction.

In this embodiment, the element spectral line lamp is used for initial calibration, as shown in Figure 3a, the angle of the angular displacement platform is adjusted so that there are at least two characteristic spectral lines on the image surface of the detector, and the position of the characteristic spectral line pixel and the current time are recorded. Angular displacement platform rotation angle ψ. Then continue to adjust the angle of rotation of the angular displacement platform until as shown in Figure 3b, so that the _λ3 spectral line moves to the position of the _λ2 spectral line when the rotation angle is ψ, record the angle of rotation of the angular displacement platform ψ' at this time, and calculate the two angles The difference between the rotation angles of the displacement platform Δ _ψ , so far all the calibration data collection is completed. Calculate the incident angle of the grating corresponding to the pixel at the position of the _λ2 spectral line when the angle of rotation of the angular displacement platform is ψ according to the above data and the grating equation, that is, the incident angle of the grating corresponding to all pixels of the detector when the rotation angle is ψ.

According to the positions of the characteristic spectral lines (at least two) on the detector image surface when the rotation angle is ψ, the wavelength values corresponding to all pixels on the detector image surface at this time can be calibrated, as shown in the following formula:

Select the effective working pixel range n _s -n _e on the detector, as shown in Figure 4. According to the calibration results, the wavelength values λ _s and λ _e on the pixels n _s and ne _e can be obtained respectively (obtained according to formula 1), so far the wavelength calibration on the image plane of the detector when the angle of rotation of the angular displacement platform is ψ is completed. Since the grating incident angle (calculated before) and spectral wavelength on _ns and _ne pixels are known at this time, the grating diffraction angle can be obtained according to the grating equation (the known incident angle and wavelength are calculated by the grating equation), Then find the included angles A _s and A _e of the incident light and diffracted light on the grating corresponding to n _s and n _e pixels in the system respectively, (incident angle + diffraction angle is the included angle), and the included angle is maintained during the grating scanning process constant.

After the calibration of the initial image plane is completed, it is necessary to rotate the grating to scan and calibrate in the direction of the low-band and high-band respectively. Take the calibration in the direction of the low-band as an example, as shown in Figure 4. According to the wavelength calibration result when the rotation angle is ψ, it can be obtained that the signal wavelength on the n _s-1 pixel at this time is λ _s-1 . In the next frame of scanning detection, by rotating the grating, λ _s-1 (n _s -1) is transferred to the n _e pixel, according to the angle A _e between the incident light and the diffracted light on the λ _s-1 and n _e pixel , then the incident angle of the grating (included angle-diffraction angle) can be calculated at this time. It can be seen from Figure 1 that the change of the grating rotation angle is equal to the change of the grating incident angle, so the change of the grating rotation angle can be obtained according to the change of the incident angle , and then calculate the angular displacement platform rotation angle ψ' at this time. At this time _, when the angle A _s and the incident angle between the incident light and the diffracted light on the n _s pixel are known, the diffraction angle at this time can be obtained, and then the n _s pixel on the n s pixel at this time can be obtained according to the grating equation Wavelength λ _s ', because the grating dispersion has good linearity in the small wavelength range, it is considered that the wavelength is linearly distributed on a frame of pixels, and the wavelength value of each pixel on the detector at this time can be obtained according to formula (1) , so far the wavelength calibration when the rotation angle is ψ' is completed.

The calibration method in the long-wave direction is almost the same as that in the short-wave direction, except that the wavelength on the n _e +1 pixel needs to be transferred to the n _s pixel during scanning. According to the above method, iterative calculations are carried out successively in the long-wave direction and short-wave direction, until the calibration of the spectral scanning of the whole band is completed. After the calibration is completed, the corresponding relationship between the grating rotation angle and the detector pixel band range can be obtained, and each band can be spliced to obtain a full-band scanning spectrum. During the raster scanning process, the grating only needs to be rotated sequentially according to the obtained rotation angles to complete the entire scanning detection process.

In conjunction with shown in Figure 6, the spectral calibration method based on the grating spectrometer has been described in the foregoing, and the present invention also provides a grating spectrometer using the above spectral calibration method, including an element spectral line lamp 15, a collimating mirror 14, an angle A displacement platform (not shown in the figure), a scanning grating 13 positioned on the angular displacement platform, a focusing mirror 12 and an imaging device 11, the optical signal sent by the elemental line lamp 15 is collimated by the collimating mirror 14 Immediately after that, the scanning grating 13 is irradiated at the first incident angle, and the diffracted optical signal diffracted by the scanning grating 13 is imaged on the imaging device 11 through the focusing mirror 12. According to the grating equation, the scanning grating 13 is rotated by an angular displacement platform, resulting in The rotation of the plane normal of the scanning grating 13 changes the first incident angle i and the diffraction angle θ, thereby changing the wavelength range on the pixel of the imaging device 11. Based on this principle, the wavelength scanning of the grating can be realized, thereby achieving wide range and high resolution. Spectral measurement.

Optionally, the elemental line lamp includes one of a mercury lamp, a deuterium lamp, a tungsten lamp or a cadmium lamp, which can be flexibly selected by those skilled in the art, and is not limited thereto.

Optionally, the imaging device is a line array detector or an area array detector, which can be flexibly selected by those of ordinary skill in the art, and is not limited thereto.

The grating spectrometer provided by the present invention applies the above-mentioned spectral calibration method, only needs to use at least two characteristic spectral lines for one calibration, and does not need other hardware parameters of the spectral dispersion system except the grating constant, and the spectrometer can achieve high precision in a wide band range Spectral scanning calibration can accurately determine the relationship between the angle of the angular displacement platform and the range of the image plane of the detector. It requires less professional auxiliary equipment, is easy to operate, has high spectral calibration accuracy, fast calibration speed, and is easy to maintain.

Those skilled in the art can clearly understand that for the convenience and brevity of the description, the specific working process of the above-described system, device and unit can refer to the corresponding process in the foregoing method embodiment, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or May be integrated into another system, or some features may be ignored, or not implemented. In another point, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, each unit may exist separately physically, or two or more units may be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

Those of ordinary skill in the art can understand that all or part of the steps in the various methods of the above-mentioned embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, and the storage medium can include: Read Only Memory (ROM, Read Only Memory), Random Access Memory (RAM, Random Access Memory), magnetic disk or optical disk, etc.

Those of ordinary skill in the art can understand that all or part of the steps in the method of the above-mentioned embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, and the above-mentioned storage The medium can be read-only memory, magnetic or optical disk, etc.

A spectral calibration method based on a grating spectrometer and a grating spectrometer provided by the present invention have been introduced in detail above. For those of ordinary skill in the art, based on the ideas of the embodiments of the present invention, they will understand both the specific implementation and the scope of application. There are changes, and in summary, the contents of this specification should not be construed as limiting the present invention.

Claims (10)

1. a kind of spectrum calibration method based on grating spectrograph, it is characterised in that methods described includes：

Selected characteristic spectral line light source, adjusting angle displacement platform corner cause at least fisrt feature spectral line and second feature spectral line to be in In detector image planes, record residing for the first corner and fisrt feature spectral line and second feature spectral line of presently described angular displacement platform Position；

The angular displacement platform is adjusted to rotate so that second feature spectral line is transferred to the first spy described in when corner is the first corner Spectral line present position is levied, records the second corner of presently described angular displacement platform, according to first corner and described second turn Angle determines outer corner difference；

Determine that the corner of the angular displacement platform is according to the outer corner difference, the wavelength of the fisrt feature spectral line and grating equation First grating incident angle corresponding to all pixels during the first corner；

The fisrt feature spectral line and the second feature spectral line and preset relation determine presently described institute during according to the first corner There is wavelength value corresponding to pixel；

The picture is determined according to the wavelength of characteristic spectral line corresponding to any pixel and first grating incident angle and grating equation First optical grating diffraction angle corresponding to member point；

Incident ray and diffraction light on the grating are determined according to first grating incident angle and the first optical grating diffraction angle Angled relationships between line, to complete the calibration of initial image planes.

2. according to the method for claim 1, it is characterised in that when carrying out the calibration of low band direction, methods described is also wrapped Include：

The 3rd wavelength value according to corresponding to determining on S pixels the preset relation；

The angular displacement platform is rotated so that corresponding 3rd wavelength value of E pixels is to complete a length scanning, according to the folder The angle of grating incident ray and diffracted ray determines second in the 3rd wavelength value of angular dependence determination and the E pixels Grating incident angle；

The variable quantity for being equal to the grating incident angle according to the variable quantity of grating corner determines the of presently described angular displacement platform Two corners；

With reference to the angle of grating incident ray and diffracted ray, second grating incident angle and described on the E pixels Two corners determine the second current optical grating diffraction angle；

The 4th wavelength value on presently described E pixels is determined according to the second optical grating diffraction angle and grating equation；

The wavelength value according to corresponding to wavelength linear distribution and the angled relationships determine current all pixels, to complete at second turn Wavelength scaling during angle, wherein, the pixel scope that effectively works is S+1 pixels between E pixels.

3. according to the method for claim 1, it is characterised in that when carrying out the calibration of long wave direction, methods described also includes：

The 5th wavelength value according to corresponding to determining on E+1 pixels the preset relation；

Rotate the angular displacement platform and cause corresponding 5th wavelength value of the S pixels, the institute determined according to the angled relationships State the angle of grating incident ray and diffracted ray on the 5th wavelength value and the S pixels and determine the 3rd grating incident angle；

The variable quantity for being equal to the grating incident angle according to the variable quantity of grating corner determines the of presently described angular displacement platform The method of three turning angles；

With reference to the angle of grating incident ray and diffracted ray, the 3rd grating incident angle and described on the S pixels The method of three turning angles determines the 3rd current optical grating diffraction angle；

The 6th wavelength value on presently described S pixels is determined according to the 3rd optical grating diffraction angle and grating equation；

The wavelength value according to corresponding to wavelength linear distribution and the angled relationships determine current all pixels, to complete at the 3rd turn Wavelength scaling during angle, wherein, the pixel scope that effectively works is S+1 pixels between E pixels.

4. according to the method for claim 1, it is characterised in that according to first grating incident angle and first grating After the angle of diffraction determines the angled relationships on the grating between incident ray and diffracted ray, methods described also includes：

Wavelength accuracy is carried out to the calibration results and carries out error calibration.

5. according to the method for claim 4, it is characterised in that described that the calibration results are carried out with wavelength accuracy progress error Demarcation, including：

The calibration results are carried out with the wavelength scaling error of all pixels in fitting of a polynomial approximate evaluation scanning process, with to calibration As a result it is modified.

6. according to the method for claim 1, it is characterised in that the preset relation is：

<mrow> <msub> <mi>&amp;lambda;</mi> <mi>n</mi> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mi>&amp;lambda;</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>&amp;lambda;</mi> <mn>1</mn> </msub> </mrow> <mrow> <msub> <mi>n</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>n</mi> <mn>1</mn> </msub> </mrow> </mfrac> <mrow> <mo>(</mo> <mi>n</mi> <mo>-</mo> <msub> <mi>n</mi> <mn>1</mn> </msub> <mo>)</mo> </mrow> <mo>+</mo> <msub> <mi>&amp;lambda;</mi> <mn>1</mn> </msub> <mo>,</mo> </mrow>

Wherein, the λ₁For the wavelength value of fisrt feature spectral line, λ₂For the wavelength value of second feature spectral line, n₁Composed for fisrt feature Pixel position where line peak value, n₂The pixel position where second feature spectral line peak value, λ_nFor the wavelength value corresponding to the n-th pixel.

7. according to the method for claim 1, it is characterised in that the grating equation is：

D (sin α+sin β)=m λ,

Wherein, d is slit spacing, i.e. grating constant；M is an integer；α is grating incident angle；β is optical grating diffraction angle；λ is pair Answer the wavelength value of spectral signal.

8. a kind of grating spectrograph for applying the method as any one of claim 1 to 7, it is characterised in that including element Spectral line lamp, collimating mirror, angular displacement platform, raster, focus lamp and imaging device on the angular displacement platform, by The optical signal that the element spectral line lamp is sent is irradiated to the raster after collimating mirror collimation with the first incidence angle, By the diffracted light signals of the raster diffraction imaging device is imaged in via focus lamp.

9. grating spectrograph according to claim 8, it is characterised in that the element spectral line lamp includes mercury lamp, deuterium lamp, tungsten One kind in lamp or cadmium lamp.

10. grating spectrograph according to claim 8, it is characterised in that the imaging device be linear array detector or Planar array detector.