WO2014117546A1

WO2014117546A1 - Spectrometer

Info

Publication number: WO2014117546A1
Application number: PCT/CN2013/085779
Authority: WO
Inventors: 潘建根
Original assignee: 杭州远方光电信息有限公司
Priority date: 2013-02-04
Filing date: 2013-10-23
Publication date: 2014-08-07
Also published as: CN103134588A

Abstract

A spectrometer comprises a light beam separator (1) and multiple array spectrometers (2). The beam separator separates the detected light into multiple light beams. The measuring ranges of the multiple array spectrometers are linked end-to-end and cover the whole detected wave band. Each array spectrometer detects each wave band accurately. The power spectrum distribution of the whole detected wave band can be obtained accurately only by single measurement. The spectrometer has the advantages of quick measuring speed, high measuring accuracy, high wavelength subdivision, high energy utilization, convenient operation, and so on.

Description

Spectrometer

[Technical Field]

The invention belongs to the field of optical radiation measurement, and in particular relates to a spectrometer.

【Background technique】

Spectrometers are used to measure the spectral composition of spectral radiant power distribution and are widely used in light source radiation measurement, color measurement, element identification, chemical analysis and other fields. Commonly used spectrometers include monochromators and multicolor instruments (multi-channel spectrometers, array fast spectrometers, etc.). Array spectrometers with multi-channel detectors have millimeter-level measurement speeds, which have developed rapidly in recent years and are becoming more widely used.

The stray light indicator is an important indicator of the array spectrometer. For the array spectrometer, stray light refers to other spectral components that are irradiated on the corresponding pixel at a specific wavelength point, and its size determines the measurement accuracy of the array spectrometer. The existing array is generally measured by the whole method, that is, the spectral power distribution of the entire tested band can be obtained in one measurement. Although the measurement method is fast and the cost is low, the stray light is large and the accuracy is relatively high. low. In addition, the bandwidth, energy efficiency, sensitivity, and wavelength resolution of the spectrometer have a greater impact on the test results.

In order to reduce the stray light, the publication No. CN101324468B discloses a technical solution for performing segment-by-segment measurement using a band pass color wheel, which is different by cutting the color filter of different conduction bands into the optical path by rotating the band color wheel. The band is introduced into the optical path for measurement. This measurement method can accurately measure each segment of the spectrum, and the measurement accuracy is high. However, since each filter needs to switch the color filter, it takes a long time and the test speed is slow; and all the measured light is introduced into the spectrometer once. Although the conduction filter used before the grating splitting, there are still many undesired reflections that bring stray light, which affects the measurement accuracy. More importantly, for the same spectrometer, the measurement band on the array detector has been determined, ie the degree of subdivision of the wavelength has also been determined. The technical solution uses the same spectrometer to measure light in different wavelength bands. For each measurement, the array detector can only be utilized in a small part and cannot be fully utilized. For example, the wavelength range of the entire test band is 380 nm to 780 nm. The measurement wavelengths on each pixel of the array detector have been determined. When measuring the 380 nm to 480 nm band, only a small number of pixels participate in the light response, and other pixels do not participate in the response, and the pixels cannot be fully utilized.

The bulletin number "CN 201476880U" discloses a spectrometer consisting of a plurality of monochromators, each of which outputs monochromatic light of different wavelength bands, and the output monochromatic light bands overlap end to end. When each monochromator is actually working, it outputs not only monochromatic light of different wavelengths by rotating the grating, but also takes a long time; and as described above, All the measured light is introduced into the monochromator at one time, introducing a large amount of stray light, and the measurement accuracy is low. In addition, since the zero-order spectral energy of the grating is the largest but the dispersion cannot occur, the spectrometer actually measures the first-order spectrum of the grating dispersion, but because of its low energy, it is limited to the sensitivity of the detector, and often requires a larger energy of incident light. In order to ensure that the first-order spectrum is detected by the detector, the energy utilization rate is low; but the incident light energy is increased, the energy of the zero-order spectrum and other grades of the spectrum is also larger, and the stray light inside the spectrometer is also more, affecting The accuracy of the measurement.

[Summary of the Invention]

In view of the above deficiencies of the prior art, the present invention aims to provide a high-precision array spectrometer which can measure the spectrum of the entire band to be measured with high precision by means of one-step measurement, which is greatly reduced. Stray light interference level, featuring fast speed, high measurement accuracy, high wavelength accuracy, high energy utilization, and convenient operation.

A spectrometer according to the present invention is realized by the following technical solutions. A spectrometer comprising a beam splitter and two or more array spectrometers, the beam splitter comprising an optical input port, two or more optical output ports, a light output port and an array The number of spectrometers is equal and one-to-one correspondence. The measurement bands of each array spectrometer are connected end to end and cover the entire band to be tested. Each light output port introduces the light to be measured into the corresponding array spectrometer, and each array spectrometer receives and measures different bands. Light.

The invention discloses a plurality of one-to-one corresponding light output ports and an array spectrometer. The measuring beam is input from the fiber input port, and the beam splitter divides the beam into a plurality of beams, each of which is incident on a different array spectrometer for measurement. Since the measurement bands of each array spectrometer are connected end to end and cover the entire band to be tested, that is, the band to be tested is divided into multiple bands, and each band is measured step by step, and the results of each band are combined to obtain the entire test. The spectral power distribution of the band. The technical solution can accurately measure each band by measuring the array spectrometer with different wavelength bands, and the spectral power distribution of the whole test band can be obtained by one-step measurement only in one measurement, and the measurement speed is fast, the accuracy is high, and the operation is convenient; Compared with the array spectrometer of the same measurement range, the array spectrometer has different measurement ranges, and the internal array detector only measures the light of a part of the band, and the array detector has a smaller wavelength range distributed on the same pixel, that is, the wavelength subdivision. Higher, measurement accuracy is also higher.

The invention can be further defined and improved by the following technical solutions.

As a technical solution, the array spectrometer includes an incident slit, a grating, and an array detector. The grating-level blaze wavelengths in each array spectrometer are within the measurement band of the array spectrometer. The light beam emitted from the light output port is incident on the incident slit, and after being dispersed by the grating, is detected by the array detector. Further, the array spectrometer further includes a collimating mirror and a converging mirror, and the collimating mirror and the converging mirror are disposed behind the optical path of the incident slit to reflect and concentrate the beam.

The spectrum of the grating diffraction is divided into zero-order spectrum, first-order spectrum, and second-order spectrum. The higher the spectral order, the better the dispersion power and the smaller the light intensity. The lower the spectral level, the weaker the dispersion power, and the light intensity is higher. Large, so the zero-order spectral energy is the largest, but no dispersion occurs. In order to obtain dispersive light with relatively high light intensity, the spectrometer actually detects the first-order spectrum with relatively high light intensity and also dispersion, but since most of the light energy of the grating is concentrated on the zero-order spectrum of the grating, the spectrometer There are more stray light inside, which has a great influence on the measurement results.

In order to reduce stray light, a blazed grating is formed by scribing a series of equidistant zigzag groove faces on a polished metal plate or a metal film of a metal substrate. The grating maximizes the zero-order principal maxima of a single groove surface diffraction and the zero-order principal of each groove surface interference, thereby causing the light energy to be greatly shifted from the interference zero-order main and concentrated to a certain polar spectrum. According to the grating equation, the blazed wavelength of each stage can be obtained. If the single-slot diffraction zero-order main maximum of the grating falls exactly on the first-order line of a certain wavelength, the wavelength is called the first-order blazed wavelength, and the first-order spectrum is obtained. The maximum light intensity combines the advantages of dispersion and light intensity. The grating first-order blaze wavelengths in each array spectrometer are within the measurement band of the array spectrometer, and the single-slot diffraction zero-order main maximum of the light incident on each array detector falls exactly on the first-order line of the blazed wavelength. That is, the light intensity of the first-order line is the strongest, and the light intensity of other lines is weak, which ensures that the stray light inside each array spectrometer is small, the signal-to-noise ratio is greatly increased, and the wavelength energy utilization rate is greatly improved.

Preferably, the grating first order blaze wavelengths in each array spectrometer are located near the center wavelength of the array spectrometer. The grating-level blaze wavelengths in different array spectrometers are located near the center wavelength of the array spectrometer to maximize energy efficiency.

Preferably, two or more band pass filters are included, and the number of the band pass filters and the array spectrometer are equal and one-to-one correspondence, and the conduction bands of the respective band pass filters are slightly larger than or equal to their corresponding ones. The measurement band of the array spectrometer; the light emitted by each light output port is filtered by the corresponding band pass filter, and each array spectrometer receives and measures the light filtered by the band pass filter. In the measurement, a plurality of band pass filters and an array spectrometer are in one-to-one correspondence, and the measuring beam is input from the fiber input port, and the beam splitter divides the beam into a plurality of beams, each of which passes through a different band pass filter and is incident respectively. Test in different array spectrometers the amount. Since the measurement bands of the corresponding array spectrometers of the respective band pass filters are the same, each band pass filter only allows the light in the measurement range of the array spectrometer to pass through, and the light outside the measurement range is not transmitted, thus entering The light inside the array spectrometer is only the light of its measurement range, which avoids the high-level spectrum mixed into other bands in the band to be tested, which can greatly reduce the stray light level and improve the measurement accuracy; or each band-pass filter only makes the array spectrometer slightly Light that is larger than its measurement range is transmitted, and other light is not transmitted. Compared with other non-measurement ranges, the undesired light entering the array spectrometer is greatly reduced. It can also greatly reduce stray light and improve measurement accuracy.

In the present invention, the band pass filter may be disposed on the optical path before the array spectrometer; or the band pass filter may be disposed inside the array spectrometer as part of the array spectrometer. The position of the bandpass filter can be flexibly set as long as it divides the beam from the source under test into different measurement bands. In addition, the conduction bands of the two or more band pass filters cover the ultraviolet to infrared band. The measurement band of the array spectrometer covers the ultraviolet-visible-infrared band, so the conduction band of the band pass filter should cover the band to be tested of the array spectrometer accordingly.

As a technical solution, including a light mixer, the light mixer is disposed on a light path before the light output port, and the light mixer is an integrating sphere or a diffuse reflection plate or a diffuse transmission plate. The mixer mixes the optical signals from the target to be measured and outputs them to the fiber input port to measure the average spectral information of the source under test.

As a technical solution, the beam splitter is a quartz bifurcated fiber or a spectroscopic half mirror or a spectroscopic half mirror set which can obtain multiple beams. Quartz fiber can transmit light in various wavelengths such as ultraviolet, visible and infrared, and has a wide range of applications.

Preferably, a control center is provided for controlling the simultaneous measurement or integration of the respective array spectrometers, the control centers being electrically coupled to the respective array spectrometers. The control center controls each array spectrometer to perform electronic synchronous measurement. The measurement of the entire band to be tested can be realized in one measurement. At the same time, after the measurement of each array spectrometer is finished, the measured results can be transmitted to the control center and integrated into the whole. The relative spectral power distribution of the measured band.

As a technical solution, the integration time of each of the array spectrometers can be set independently or automatically according to the intensity of the incident light. The integration time of each array spectrometer can be set independently to suit different incident light. At the same time, according to the intensity of the incident light, each array spectrometer can also automatically adjust the integration time to obtain a reasonable A/D value. Preferably, the band pass filter and the array spectrometer are arranged side by side. In addition, the band pass filter and the array spectrometer are not limited to this arrangement, and other arrangements such as a band pass filter and an array spectrometer are disposed on one spherical surface.

Preferably, the housing includes a beam splitter, an array spectrometer, and a band pass filter disposed in the chassis. Each unit is housed in a single chassis with a high degree of integration, design integration, and ease of operation.

In addition, a convergence device, an imaging device, a dimming device, and the like may be disposed in the optical path. For example, comprising an imaging device disposed on an optical path before the beam splitter and the beam splitter being located at an image plane position of the imaging device; or the imaging device being disposed after the beam splitter, before the array spectrometer The light path. The imaging device here is a lens or other device. If the imaging device is disposed in front of the beam splitter, the light of the target to be measured is imaged by the imaging device to the input port of the beam splitter to measure the image spectrum and image spectrum of the target to be measured. Radiation; if the imaging device is placed behind the beam splitter and before the array spectrometer, the imaging device concentrates the light output through the optical output port to the light entrance of the different array spectrometer for measurement. Or including a dimmable aperture disposed on the optical path before the beam splitter; or the dimmable aperture is disposed after the beam splitter and on the optical path preceding the array spectrometer. The dimming aperture is disposed in front of the beam splitter to limit the light incident on the object to be measured in the input port of the beam splitter; the adjustable aperture is disposed after the beam splitter, and the array spectrometer is used to limit incidence into the array spectrometer The light.

In summary, the present invention uses a beam splitter to divide the measured light into a plurality of light beams, and accurately measures each wavelength band through each array spectrometer whose measurement range is connected end to end and covers the entire band to be tested, and only one measurement is needed. Through the piece by piece measurement, the spectral power distribution of the entire band to be tested can be obtained, which has the characteristics of fast measurement speed, high wavelength subdivision, high measurement accuracy and convenient operation; in addition, the conduction band is respectively set in front of each array spectrometer Measuring each bandpass filter with the same band can greatly reduce stray light interference and further improve measurement accuracy.

[Description of the Drawings]

Figure 1 is a schematic view of Embodiment 1;

Figure 2 is a schematic view of Embodiment 2;

Figure 3 is a schematic view of Embodiment 3.

1-beam splitter; 1-1-optical input port; 1-2-optical output port; 2-array spectrometer; 3-band pass filter Color film; 4-control center; 5-chassis; 6-mixer.

【detailed description】

Example 1

As shown in FIG. 1, this embodiment discloses a spectrometer comprising a beam splitter 1, five band pass filters 3, five array spectrometers 2, a control center 4 and a chassis 5; a beam splitter 1, a band pass The color filter 3 and the array spectrometer 2 are both disposed in the chassis 5.

The beam splitter 1 is a "one-to-five" bifurcated fiber, including one optical input port 1-1 and five optical output ports 1-2; the wavelength of the light to be measured is 380 nm-780 nm, and the measurement bands of the respective array spectrometers 2 are respectively For the 380 nm-460 nm, 460 nm-540 nm, 540 nm-620 nm, 620 nm-700 nm, and 700 nm-780 nm, the conduction bands of the respective array spectrometers 2 overlap first and cover the entire test band; the conduction of each band pass filter 3 is The band is slightly larger than the measurement band of its corresponding array spectrometer 2, and its conduction band is also 360 nm-480 nm 440 nm-560 nm, 520 nm-620 nm, 620 nm-700 nm, and 700 nm-780 nm. During the test, the array spectrometer 2 receives the light beams emitted by the light output ports 1-2 filtered by the respective band pass filters 3, and the five array spectrometers 2 measure 380 nm - 460 nm, 460 nm - 540 nm, 540 nm - 620 nm, 620 nm - Spectral power distribution in the 700 nm and 700 nm-780 nm bands.

This embodiment also includes a control center 4 that controls and integrates the measurements of the various array spectrometers 2, and the control center 4 is electrically coupled to each of the array spectrometers 2. After the end of each array spectrometer 2 measurement, the respective measured results are transmitted to the control center 4 and integrated into the relative spectral power distribution of the entire band to be tested.

In this embodiment, the measurement of the entire band to be tested can be obtained by one measurement, the stray light can be greatly reduced, the wavelength subdivision is high, and the measurement speed is fast, the accuracy is high, and the operation is convenient.

Example 2

As shown in FIG. 2, unlike the first embodiment, the beam splitter 1 of the present embodiment is a beam splitting half mirror group, the light beam is input from the light output port 1-1, and the beam splitting half mirror group includes three. Each of the prisms has a light output port 1-2; each of the light output ports 1-2 is respectively provided with an array spectrometer 2, and each array spectrometer 2 is provided with a band pass filter 3 in front.

In this embodiment, each band pass filter 3 corresponds to each array spectrometer, and the conduction band of each band pass filter 3 is equal to the measurement band of its corresponding array spectrometer 2. The band to be tested is

380nm-780nm, the measurement bands of the three array spectrometers 2 are 380nm-500nm, 500nm-620nm and 620nm-780nm, respectively, and the conduction band of each band pass filter 3 is also 380nm-500nm. 500 nm to 620 nm and 620 nm to 780 nm.

In addition, the array spectrometer 2 in this embodiment includes an incident slit, a blazed grating, and an array detector. The first-order blazed wavelength of the grating is in the measurement band of the corresponding array spectrometer 2, and the measured light source is filtered by the band pass filter. After that, the single-channel diffraction zero-order main maximum of the transmitted light falls on the first-order spectral line of the blazed wavelength, that is, the light intensity of the first-order line is the strongest, and the light intensity of the other-level lines is weak, thereby It ensures that the stray light inside the array spectrometer 2 is small, the signal-to-noise ratio is greatly increased, and the wavelength energy utilization rate is greatly improved.

Example 3

As shown in FIG. 3, unlike the first embodiment, the light mixer 6 is included, and the light mixer 6 is an integrating sphere, which is disposed on the optical path before the light output port 1-2, and the measured light passes through the light mixer. 6 is fully mixed, and then filtered by each band pass filter 3 to enter the corresponding array spectrometer 2 for analysis and measurement.

Claims

Claim

A spectrometer comprising: a beam splitter (1) and two or more array spectrometers (2), said beam splitter (1) comprising an optical input port (1-1), Two or more light output ports (1-2), the number of light output ports (1-2) and the array spectrometer (2) are equal and one-to-one correspondence, and the measurement bands of each array spectrometer (2) are connected end to end. And covering the entire band to be tested; each light output port (1-2) introduces the light to be measured into the corresponding array spectrometer (2), and each array spectrometer (2) receives and measures the light of different bands.

2. A spectrometer according to claim 1, wherein said array spectrometer (2) comprises an entrance slit, a grating and an array detector, and the grating first-order blaze wavelengths in each array spectrometer (2) Within the measurement band of the array spectrometer (2).

3. A spectrometer according to claim 2, characterized in that the grating first order blaze wavelengths in each array spectrometer (2) are located near the central wavelength of the array spectrometer (2).

4. A spectrometer according to claim 1, comprising two or more band pass filters (3), band pass filters (3) and array spectrometer (2) Equal and one-to-one correspondence, the conduction band of each band pass filter (3) is slightly larger than or equal to the measurement band of its corresponding array spectrometer (2); the light emitted by each light output port (1-2) is corresponding The band pass filter (3) filters, and each array spectrometer (2) receives and measures the light filtered by the band pass filter (3).

5. A spectrometer according to claim 4, characterized in that said band pass filter (3) is arranged on the optical path before the array spectrometer (2); or said band pass filter ( 3) Set inside the array spectrometer (2) and be part of the array spectrometer (2).

6. A spectrometer according to claim 1, comprising a control center (4) for controlling the simultaneous measurement or integration of the respective array spectrometers (3), said control center (4) and respective array spectrometers (2) ) All electrical connections.

7. A spectrometer according to claim 1, characterized in that the integration time of the respective array spectrometers (3) can be set independently or automatically according to the intensity of the incident light.

8. A spectrometer according to claim 1, wherein said beam splitter (1) is a bifurcated optical fiber or a spectroscopic transflective or a spectroscopic half mirror that can obtain multiple beams. group.

9. A spectrometer according to claim 1, comprising a light mixer (6), said light mixer (6) being arranged at a light output port of the beam splitter (1) (1-2) On the previous optical path, the light mixer (6) is an integrating sphere or a diffuse reflector or a diffuse transmission plate.

10. A spectrometer according to claim 4, comprising a chassis (5), said beam splitter (1), array spectrometer (2), band pass filter (3) are all disposed at Inside the chassis (5).