CN102564591B - Spectrum analyzer and spectrum analyzing method - Google Patents

Abstract

The invention relates to a spectrum analyzer, which comprises a light source, a light collecting unit, a light splitting unit, an imaging unit, a detecting unit and a processing unit. The light source emits measuring light. The light collecting unit couples the measuring light to the light splitting unit which comprises a first light splitting module and a second light splitting module. The measuring light is split by the first light splitting module in an X direction, split by the second light splitting module in the same direction, imaged by the imaging unit and then received by the detecting unit. Signals received by the detecting unit are processed by the processing unit so as to obtain a spectrogram corresponding to a narrow wave band. The invention further provides a spectrum analyzing method. The spectrum analyzer and the spectrum analyzing method have the advantage of high spectral resolution of the narrow wave band.

Description

A kind of spectroanalysis instrument and spectroscopic analysis methods

Technical field

The present invention relates to a kind of spectroanalysis instrument and spectroscopic analysis methods, relate in particular to a kind of spectroanalysis instrument and spectroscopic analysis methods that can effectively improve narrow-band spectrum resolution.

Background technology

In spectrographic detection field, the General Requirements spectra collection time is short as far as possible, and the spectral range once gathering is wide as far as possible; Whole detection system is wanted firm compactness, is easy to carry and outdoor use; These characteristics can not be sacrificed spectral resolution and precision, also will reduce as far as possible calibration and various drift-compensated workload.

At present, the structure of common spectrometer has Czerny-Turner structure, Paschen-Runge structure, flat filed concave grating beam splitting system, echelle grating bidimensional spectroscopy system etc.

Volume is little, resolution advantages of higher because it has for echelle grating bidimensional spectroscopy system, in the high-resolution occasion of needs, obtains more application.

Echelle grating bidimensional spectroscopy system, as shown in Figure 1, generally comprises light source 1, entrance slit 3, collimating mirror 4,grating 6 andprism 5,imaging lens 7 and detector 8.Measuring light introduces after entrance slit bycertain focus lamp 2, the collimated light beam obtaining after collimating mirror 4 incides on the mutuallyperpendicular grating 6 of dispersion direction andprism 5, realize the two-dimension chromatic dispersion of incident light, light after two-dimension chromatic dispersion incides onimaging lens 7, throughimaging lens 7, on the test surface ofdetector 8, be in image planes, to obtain a two dimension spectrogram corresponding to whole broadband, i.e. wide range spectrogram from long wave to shortwave.

Above-mentioned middle ladder bidimensional spectroscopy system has following feature: in wide range spectrogram, spectral line presents Two dimensional Distribution in image planes, and from shortwave to long wave, (160～850nm) spectral profile shows that shortwave spectral profile is dredged, the closeer feature of long wave spectral profile.

Based on These characteristics, echelle grating bidimensional spectroscopy system has following deficiency:

1, spectral profile is inhomogeneous

Wavelength is longer, and corresponding Refractive Index of Glass Prism is less, at a minute spectral line for light time shortwave part, just occupies most of spectrogram, and the spectral line of long wave part is very intensive and only occupy the small part of spectrogram, and spectral profile is inhomogeneous;

2, especially long wave direction spectral resolution is low for narrow wave band

The optical resolution of this type of beam splitting system, be limited to the characteristic of echelle grating, wavelength is longer, optical resolution is larger, resolving effect is poorer, as Long wavelength region optical resolution can become several times of short wavelength regions optical resolution, can become the more than 2 times of shortwave 200nm optical resolution corresponding to wave band as above in 300nm, had a strong impact on the spectrally resolved ability of system;

3, measuring error is large

The numerous spectral lines of rare earth element and subgroup element all concentrate on 300～500nm wave band, spectral line is intensive especially, more serious in these occasion overlap of spectral lines interference ratio, the spectral resolution of conventional echelle grating bidimensional spectroscopy system is not enough to tell interference spectral line, make beam splitting system cannot effectively eliminate spectral line interference problem, cause measuring error, be unfavorable for detecting.

Summary of the invention

In order to solve above-mentioned deficiency of the prior art, the invention provides that a kind of cost is lower, reliability is high, can improve spectroanalysis instrument and spectroscopic analysis methods that traditional echelle grating bidimensional spectroscopy system narrow-band spectrum is differentiated the problem of rate variance.

For achieving the above object, the present invention adopts following technical scheme:

A spectroanalysis instrument, comprising:

Light source, described light source sends measurement light;

Light collection unit, described light collection unit is optically coupled to spectrophotometric unit by measurement;

Spectrophotometric unit, described spectrophotometric unit comprises the first spectral module and the second spectral module, measures light and by described the second spectral module, carried out the light splitting of equidirectional after described the first spectral module directions X light splitting;

Image-generating unit and probe unit, described measurement light is detected unit reception be imaged cell imaging after described the second spectral module light splitting after again;

Processing unit, the signal that described processing unit processes probe unit receives, obtains the spectrogram that narrow wave band is corresponding.

Further, described the first spectral module also carries out the light splitting of Y-direction to measuring light, and directions X and Y-direction are not parallel.

As preferably, described directions X is mutually vertical with Y-direction.

Further, described the first spectral module comprises the first prism and the first grating, and described the first grating pair is measured light and carried out the light splitting of directions X.

As preferably, described the first grating is echelle grating.

As preferably, described the second spectral module is echelle grating or plane grating or the concave grating of reflection or transmission.

As preferably, described image-generating unit comprises the first image-forming module and the second image-forming module, and described probe unit comprises the first detector and the second detector;

Measure light after described the first spectral module light splitting, a part is received by the first detector after the first image-forming module imaging, and a part further by the second spectral module light splitting, received by the second detector after the second image-forming module imaging again; The signal that described processing unit processes the first detector and the second detector receive, obtains respectively broadband and spectrogram corresponding to narrow wave band.

As preferably, described the second spectral module is arranged on the second image-forming module.

As preferably, described the first detector and the second detector are same detector.

The present invention also provides a kind of spectroscopic analysis methods, comprises the following steps:

A, adopt above-mentioned arbitrary described spectroanalysis instrument;

The measurement light that B, light source send is after described the first spectral module light splitting, further by described the second spectral module light splitting, after image-generating unit imaging, be detected unit and receive, the signal that probe unit receives described in processing unit processes, obtains the spectrogram that narrow wave band is corresponding.

Compared with prior art, the present invention has following beneficial effect:

1, the light splitting ability providing by the second spectral module, has significantly promoted especially optical resolution corresponding to long wave direction of narrow wave band.

2, can obtain conventional wide range spectrogram and high-resolution narrow wave band spectrogram as corresponding in long-wave band corresponding from long-wave band to short-wave band, have advantages of that traditional echelle grating spectrogram covers the corresponding spectral resolution of the wide and narrow wave band of wavelength coverage high.

3, measure light and after twice light splitting, be imaged detection, the optical lens that it adopts and planar array detector cost are lower, can within the scope of limited cost, reach better effect.

Accompanying drawing explanation

Fig. 1 is the echelle grating bidimensional spectroscopy system schematic of background technology;

Fig. 2 is the structural representation of the spectroanalysis instrument of the second spectrophotometric unit in embodiment 1 while being reflective gratings.

Fig. 3 is the structural representation of the spectroanalysis instrument of the second spectrophotometric unit in embodiment 1 while being transmission-type grating.

Fig. 4 is the spectrogram that conventional echelle grating bidimensional spectroscopy optical system obtains.

Fig. 5 is the spectrogram that the second light path obtains, and has shown from 300 to 500nm spectral profile.

Fig. 6 is the structural representation of spectroanalysis instrument when the second spectral module is arranged between the first spectral module and the first image-forming module inembodiment 2;

Fig. 7 is the structural representation of spectroanalysis instrument when the second spectral module is arranged between the first image-forming module and the first detector inembodiment 2;

Fig. 8 is the structural representation of spectroanalysis instrument in embodiment 3.

Embodiment

Embodiment 1

Refer to Fig. 2, Fig. 3, a kind of spectroanalysis instrument, comprises light source, light collection unit, spectrophotometric unit, image-generating unit, probe unit and processing unit;

In the present invention, describedlight source 11 is a kind of in inductively coupled plasma (ICP), laser instrument, element lamp, xenon lamp, flame etc., and the present embodiment is ICP light source.Indutively coupled plasma light source is the most frequently used atomic emission spectrometry light source, and conventionally, it is comprised of four parts such as radio-frequency generator, inductive coil, plasma quarter bend and air supply systems;

Described light collection unit comprisesfocus lamp 12, entersseam 13 andfocus lamp 14, and the measurement that described light collection unit sendslight source 11 is optically coupled to the first spectral module.Described light source and light collection unit are the state of the art, do not repeat them here.

Described spectrophotometric unit comprises the first spectral module and the second spectral module, measures light and by described the second spectral module, carried out the diffraction light splitting of equidirectional after described the first spectral module directions X diffraction light splitting;

Described the first spectral module and the second spectral module can be diffraction light splitting to measuring the light splitting of light, can be also refraction light splitting;

At the present embodiment, the first spectral module comprises thefirst grating 16 and thefirst prism 15, and 16 pairs, described the first grating is measured light and carried out the diffraction light splitting of directions X, and 15 pairs, described the first prism is measured light and carried out the refraction light splitting of Y-direction; Described directions X and Y-direction are not parallel.

Preferably, described the first grating 16 is echelle grating.

Preferably, directions X is mutually vertical with Y-direction.

Measure light by the first grating 16 diffraction light splitting after, between at different levels, can overlap, by dispersion, divide light direction and orthogonal thefirst prism 15 of thefirst grating 16 again, form two-dimension spectrum image in image planes, can access whole measurement wave band is spectrogram corresponding to broadband; But because echelle grating is along with wavelength is elongated, the order of diffraction time can diminish, thereby causes resolution to decline, so long-wave band spectra resolution rate can be poorer than short-wave band, when analyzing the very abundant material of long wave spectral line spectral line disturb just more serious, as analyzed the rare earth element in ferrous metal iron.

In order to improve spectral resolution, the secondspectral module 172 is set; A minute light direction for described the secondspectral module 172 divides light direction identical with the dispersion of thefirst grating 16, identical with directions X; Measure light after the first spectral module light splitting further by described the secondspectral module 172 light splitting; Echelle grating, plane grating or concave grating that described the secondspectral module 172 is reflection or transmission.

Described measurement light is detected unit reception be imaged cell imaging after described the secondspectral module 172 light splitting after again; The signal that described processing unit processes probe unit receives, obtains the spectrogram that narrow wave band is as corresponding in long-wave band.

Described image-generating unit comprises the second image-formingmodule 19 and the first image-formingmodule 171, and described probe unit comprises thefirst detector 18 and thesecond detector 20; Described processing unit (not marking in figure) is connected with thesecond detector 20 with thefirst detector 18 respectively.

Measure light after described the first spectral module light splitting, a part is received by thefirst detector 18 after the first image-formingmodule 171 imagings, and a part further by the secondspectrophotometric unit 172 light splitting, received by thesecond detector 20 after the second image-formingmodule 19 imagings again;

Thesecond detector 20 is arranged on to narrow wave band after the second image-formingmodule 19 imagings, as the position at the corresponding spectrum of long-wave band place, can be surveyed and obtain the higher spectrogram of resolution that narrow wave band is as corresponding in long-wave band.The selected long-wave band of the present embodiment is 300～500nm.

The signal that described processing unit processes thefirst detector 18 and thesecond detector 20 receive, obtains respectively the higher spectrogram of resolution that spectrogram corresponding to broadband and narrow wave band are as corresponding in long-wave band, please respectively referring to Fig. 4, Fig. 5; Wherein, Fig. 5, for to the spectrogram obtaining after the further light splitting of Fig. 4 long-wave band, has shown the spectral profile from 300～500nm.

Image-generating unit and probe unit are set according to demand: if only need, obtain spectrogram corresponding to high-resolution narrow wave band,, image-generating unit can only comprise the second image-forming module, and probe unit only comprises the second detector; If desired obtain wide spectrum (wide spectrum is wave band corresponding from long wave to shortwave) and spectrogram corresponding to narrow wave band,, image-generating unit comprises the first image-forming module and the second image-forming module, and probe unit comprises the first detector and the second detector.

The present embodiment, need to obtain broadband and spectrogram corresponding to narrow wave band difference, and image-generating unit need to comprise the first image-forming module and the second image-forming module, and probe unit need to comprise the first detector and the second detector.

Preferably, in the present embodiment, described the secondspectral module 172 is arranged on the first image-formingmodule 171; In whole image planes due to the first image-formingmodule 171, all there is broadband to comprise the spectral profile of long-wave band and short-wave band, therefore for the secondspectral module 172 that further narrow wave band is carried out to light splitting, can be arranged on the first image-formingmodule 171 and can receive arbitrary position of measuring light.

Preferably, in the present embodiment, the first image-formingmodule 171 is imaging concave mirror, and the secondspectral module 172 is plane of reflection grating; Described the secondspectral module 172 is arranged on the first image-formingmodule 171 center.

Measurement light through the first spectral module light splitting is incident on the first image-formingmodule 171, and a part is received by thefirst detector 18 after the first image-formingmodule 171 imagings; A part of by diffraction after the secondspectral module 172 reflections or transmission, measurement direction of light changes, and after the second image-formingmodule 19 imagings, by thesecond detector 20, is received; The introducing of the secondspectral module 172, has increased the dispersive power of system to narrow wave band, has improved Spectral resolution.

Described the second image-formingmodule 19 is simple glass focus lamp, and described thesecond detector 20 is common planar array detector.Described the first image-formingmodule 171 and thefirst detector 18 are the state of the art, do not repeat them here.

The present embodiment also provides a kind of spectroscopic analysis methods, comprises the following steps:

The spectroanalysis instrument of the raising spectral resolution described in A, employing the present embodiment;

B, measure light after described the first spectral module light splitting, further by described thesecond spectrophotometric unit 172 light splitting, be detected unit and receive after image-generating unit imaging, the signal that probe unit receives described in processing unit processes, obtains spectrogram corresponding to long-wave band.

The light splitting ability providing by the second spectral module, has significantly promoted especially optical resolution corresponding to long-wave band of narrow wave band.

When obtaining conventional broadband spectrogram, obtained high-resolution narrow wave band as long-wave band spectrogram, had advantages of that traditional echelle grating spectrogram covers wavelength coverage extensively and narrow-band spectrum resolution is high.

Carry out optical lens and planar array detector cost that secondary light splitting adopts lower, can within the scope of limited cost, reach better effect.

Embodiment 2

A spectroanalysis instrument, different from the spectroanalysis instrument described in embodiment 1:

The first image-formingmodule 27 and the secondspectral module 272 are separate device, described the secondspectral module 272 is arranged between the first spectral module and the first image-formingmodule 27, as shown in Figure 6, or be arranged between the first image-formingmodule 27 and thefirst detector 18, as shown in Figure 7.The second spectral module is the concave grating of reflection or transmission, the present embodiment, and described the secondspectral module 272 is transmission concave grating.

Measure light by after the first spectral module light splitting through the secondspectral module 272 light splitting, the second spectral module separates 1 grade of light from 0 grade of light, 0 grade of light is not introduced extra light splitting ability, therefore it is constant that the spectrogram obtaining on thefirst detector 18 maintains broadband spectrogram, especially spectrogram corresponding to short-wave band, 1 grade of light can be introduced the secondary dispersion that the second spectral module is introduced, and therefore on thesecond detector 20, just can obtain and have the more spectrogram corresponding to narrow wave band of high resolution capacity.The present embodiment, narrow wave band is short-wave band 200～300nm.

The present embodiment also provides a kind of spectroscopic analysis methods, different from the spectroscopic analysis methods in embodiment 1:

1,, in steps A, adopt the spectroanalysis instrument of the present embodiment;

2, measure light by after the first spectral module light splitting after the secondspectral module 272 light splitting, the secondspectral module 272 separates 1 grade of light from 0 grade of light, 0 grade of light is not introduced extra light splitting ability, therefore it is constant that the spectrogram obtaining on thefirst detector 18 maintains broadband spectrogram, 1 grade of light direction has the secondary dispersion that the second spectral module is introduced, and therefore on thesecond detector 20, just can obtain and have the narrower wave band spectrogram as corresponding in short-wave band of high resolution capacity.

Embodiment 3

Refer to Fig. 8, a kind of spectroanalysis instrument, different from the spectroanalysis instrument described in embodiment 2:

Image-generating unit only comprises the second image-formingmodule 19, and probe unit only comprises thesecond detector 20;

The present embodiment, narrow wave band is long-wave band 500nm～650nm.

The present embodiment also provides a kind of spectroscopic analysis methods, different from the spectroscopic analysis methods in embodiment 2:

1,, in steps A, adopt the spectroanalysis instrument of the present embodiment;

2, measure light by after the first spectral module light splitting through the secondspectral module 272 light splitting, the secondspectral module 272 separates 1 grade of light, process 1 grade of light that thesecond detector 20 receives, can obtain and there is the narrower wave band spectrogram as corresponding in long-wave band of high resolution capacity.

Above-mentioned embodiment should not be construed as limiting the scope of the invention.Key of the present invention is: measure light and by described the second spectral module, carried out the light splitting of equidirectional after described the first spectral module directions X light splitting, improved the spectral resolution that narrow wave band is corresponding.In the situation that not departing from spirit of the present invention, within any type of change that the present invention is made all should fall into protection scope of the present invention.

Claims (8)

1. a spectroanalysis instrument, comprising:

Light source, described light source sends measurement light;

Light collection unit, described light collection unit is optically coupled to spectrophotometric unit by measurement;

Spectrophotometric unit, described spectrophotometric unit comprises the first spectral module and the second spectral module, measure light and by described the second spectral module, carried out the light splitting of equidirectional after described the first spectral module directions X diffraction light splitting, described the second spectral module separates 1 grade of light from 0 grade of light;

Image-generating unit and probe unit, described image-generating unit comprises the first image-forming module and the second image-forming module, described probe unit comprises the first detector and the second detector; Measure light after described the first spectral module light splitting, a part is received by the first detector after the first image-forming module imaging, a part is further separated 1 grade of light by the second spectral module from 0 grade of light, described 1 grade of light is received by the second detector after the second image-forming module imaging again;

Processing unit, the signal that described processing unit processes probe unit receives, obtains the spectrogram that narrow wave band is corresponding.

2. spectroanalysis instrument according to claim 1, is characterized in that: described the first spectral module also carries out the light splitting of Y-direction to measuring light, and directions X and Y-direction are not parallel.

3. spectroanalysis instrument according to claim 2, is characterized in that: described directions X is mutually vertical with Y-direction.

4. spectroanalysis instrument according to claim 2, is characterized in that: described the first spectral module comprises the first prism and the first grating, and described the first grating pair is measured light and carried out the light splitting of directions X.

5. spectroanalysis instrument according to claim 4, is characterized in that: described the first grating is echelle grating.

6. spectroanalysis instrument according to claim 1, is characterized in that: described the second spectral module is echelle grating or plane grating or the concave grating of reflection or transmission.

7. spectroanalysis instrument according to claim 1, is characterized in that: described the first detector and the second detector are same detector.

8. a spectroscopic analysis methods, comprises the following steps:

A, provide claim 1～7 arbitrary described spectroanalysis instrument;

The measurement light that B, light source send is after described the first spectral module light splitting, further by described the second spectral module light splitting, after image-generating unit imaging, be detected unit and receive, the signal that probe unit receives described in processing unit processes, obtains the spectrogram that narrow wave band is corresponding.

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