CN112945857A - Outer ball type diffuse reflection spectrum measuring device - Google Patents
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Abstract
The invention discloses an external sphere type diffuse reflection spectrum measuring device which comprises a light source capable of emitting near infrared light, a first optical system for transmitting a part of light emitted by the light source to a sample surface, a second optical system for transmitting a part of light emitted by the light source to a reference channel system, collecting diffuse reflection light from the sample surface and transmitting the diffuse reflection light to a signal channel system, an integrating sphere for receiving optical signals transmitted by the reference channel system and the signal channel system according to a time domain sequence, a spectrum analyzer connected with the output end of the integrating sphere through a third optical fiber, and a set of methods for optimally calculating the optimal working distance by matching with the optimal use effect of the device, the optimal signal-to-noise ratio and the fastest measuring efficiency. The invention is convenient to carry, greatly reduces the time required by full spectrum acquisition and data analysis, improves the quality of signal light, and improves the measurement accuracy and the reliability of measurement results.
Description
[ technical field ] A method for producing a semiconductor device
The invention belongs to the technical field of spectral information measurement, and particularly relates to an outer sphere type diffuse reflection spectrum measuring device.
[ background of the invention ]
Molecules have certain discrete energy levels and in the near infrared spectrum, the molecule absorbs photon energy, inducing a transition from the ground state to a second excited state, which is called overtone. Near infrared spectroscopy is based on molecular vibrational modes, and near infrared radiation can typically penetrate samples of considerable thickness, so near infrared spectroscopy techniques, such as diffuse reflectance near infrared spectroscopy, can be very useful detection tools. In addition, near infrared spectroscopy is generally sample preparation-free and can be used for material characterization and molecular analysis applications such as pharmaceutical, medical diagnostics, neurology, neuroimaging, neonatal research, urology, food and pesticide quality control, and the like.
Near infrared spectroscopy is the superimposed manifestation of the absorption characteristics of various chemical components in a material. Different chemical bonds absorb at different wavelengths, and interactions between chemical components, multiple scattering, and differences in particle size, shape, and orientation produce multiple absorption bands in the raw spectral data.
According to the American society for testing and materials (ASTM E1790-2016), the practical definition applies to the short-wave near infrared region, approximately 780nm to 1100 nm; the long-wave near-infrared region is about 1100nm to 2500 nm. These near infrared absorption bands are associated with functional groups such as carbon-hydrogen bonds (C-H), hydrogen-oxygen bonds (O-H), and nitrogen-hydrogen bonds (N-H), which have higher frequencies in the mid-infrared band, and thus the first, second, and even third overtones can be found in the near-infrared band. Weaker absorption means that a longer optical path is required for the useful signal, and therefore the third and above overtones that can typically be found in the short-wave near-infrared region are less practical. On the contrary, the long-wave near infrared region has large information amount and less spectrum overlapping, so the method is more useful for near infrared spectrum analysis.
The concentration of components such as water, protein, fat and carbohydrates can in principle be determined using classical absorption spectroscopy. However, the spectral changes caused by the physical properties obscure the chemical information. This makes near infrared spectroscopy a two-stage method that requires calibration according to more accurate reference methods, such as classical wet chemistry methods. Once calibrated in place, near infrared spectroscopy can be used as a very simple and fast way to predict compositional information.
With the development of specialized near infrared spectrometers and mathematical models for processing spectral data, multiple constituent information can be obtained simultaneously. However, the application of near infrared spectroscopy in qualitative analysis is relatively new, and related technologies are continuously developed. Specialized near-infrared instruments are being developed from a laboratory stationary state to an on-line production state and a mobile state. The method provides new challenges for the prior art in the face of complex environments such as dust, high temperature and humidity, vibration and the like.
Near infrared spectroscopy can be performed by comparing the near infrared absorption spectra of an unknown material to a known reference material. Therefore, obtaining high quality near infrared spectra is one of the important goals for instrument manufacturers. More specifically, high quality near infrared spectra have high signal-to-noise ratios, high resolution, and spectral reproducibility.
Near infrared spectroscopy instruments generally comprise two main functional modules: a light emitting and collecting module and a light measuring module. The signal light is the portion of the light that enters the interior of the sample and returns to carry the constituent information. A portion of the light that does not carry constituent information, such as specular reflections and stray light, can contribute noise and error to the system. Of course, the noise also includes system noise such as dark current noise and the like. A good signal-to-noise ratio depends mainly on well designed optical systems, i.e. light emitting and collecting modules. The spectral resolution depends on the light measuring module. For grating-based modules, the size of the slit and the number of detectors in the detector array together determine the spectral resolution. For Fourier Transform (FT) based modules, the distance of movement of the mirror determines the resolution. Spectral repeatability is reflected by the standard error of scanning the spectral peaks multiple times. It is a key index of system stability and plays an important role in model transfer.
Emitted from the light source to the sample surface and providing specularly and diffusely reflected light. Specular reflection refers to reflection from the surface of the sample at an angle of incidence equal to the angle of reflection. It is not transmitted into the sample for interaction; therefore, it is preferable to exclude it from the optical path of the signal beam. Diffuse reflectance is the result of light interacting with various chemical and physical factors within the sample reaction volume and is a major component of the measurement.
The light emitting and collecting module includes a first light path for transmitting light to the sample and a second light path for collecting light carrying information on the useful component. In patent CN1079050A, light is transmitted through a light-transmissive opening in the wheel and illuminates the sample through a window in the integrating sphere. Diffuse reflected light is collected by the sphere through the same window and detected by the light sensor. In such a device, most of the specular reflection from the window is collected by the integrating sphere and is difficult to separate from the signal.
WO2010/029390a1 discloses a system and method that addresses some of the problems described above. In this invention, a specific mirror curvature is designed for the daylighting device to reflect all light to the central region in the absence of the sample, without the daylighting fiber, thus this arrangement ensures that all light collected when testing the sample is diffusely reflected. While this arrangement solves the above problem, it uses about seven optical fibers to collect the signals, which increases the complexity of the system and may not be very efficient. With the addition of the optical fiber, sufficient signal light may not be collected, resulting in a sufficiently high signal-to-noise ratio. There is therefore a need in the art for a high performance optical structure based on spatial optical design and a new method for collecting near infrared signals.
Therefore, it is necessary to provide a new external sphere type diffuse reflection spectrum measuring device to solve the above problems.
[ summary of the invention ]
The invention mainly aims to provide an outer sphere type diffuse reflection spectrum measuring device which is convenient to carry, greatly reduces the time required by full spectrum collection and data analysis, improves the quality of signal light, and improves the measuring accuracy and the reliability of a measuring result.
The invention realizes the purpose through the following technical scheme: an external sphere type diffuse reflection spectrum measuring device comprises a light source capable of emitting near infrared light, a first optical system for transmitting a part of light emitted by the light source to a sample surface, a second optical system for transmitting a part of light emitted by the light source to a reference channel system, collecting diffuse reflection light from the sample surface and transmitting the diffuse reflection light to a signal channel system, an integrating sphere for receiving optical signals transmitted by the reference channel system and the signal channel system according to a time domain sequence, and a spectrum analyzer connected with the output end of the integrating sphere through a third optical fiber.
Furthermore, the first optical path system comprises a shell enclosing the light source, the shell comprises a light reflection arc surface and a cylinder, the light reflection arc surface is positioned at the top and enables the light emitted by the light source to be emitted in cylindrical collimation, the cylinder is provided with a first optical channel, and part of the light emitted by the light source forms cylindrical collimation light through the light reflection arc surface and is emitted through the first optical channel; and a polarizing component and an exit window are sequentially arranged at the exit window of the first optical channel along the light beam direction.
Further, the second optical system comprises a second optical channel which is arranged in the center of the first optical channel in parallel and penetrates through the polarization assembly, and a 45 ° reflector which is positioned above the second optical channel, wherein the second optical channel is positioned right below the light source, the 45 ° reflector is positioned between the light source and the second optical channel, and an optical bus of the 45 ° reflector is positioned on the same optical horizontal line with the signal channel system and the reference channel system;
the signal channel system comprises a second lens barrel and a second lens which is arranged in the second lens barrel and is directly coupled with a signal port of the integrating sphere.
Further, the second optical channel extends upwards from the upper surface of the exit window; the second optical channel is disposed coaxially with the first optical channel.
Further, a high-reflection material coating is arranged on one side surface, facing the light source, of the 45-degree reflector; and the surface of one side of the 45-degree reflector facing the second optical channel is coated with an infrared reflection coating.
Furthermore, the reference channel system comprises a first optical fiber for receiving the reference light transmitted by the 45 ° reflector and transmitting the reference light to the reference port of the integrating sphere, and a reference shutter arranged at one end of the first optical fiber and coupled to the reference port.
Furthermore, the reference channel system further comprises a first lens barrel and a first lens arranged in the first lens barrel, and the other end of the first optical fiber is connected to the first lens barrel and used for receiving the optical signal output by the first lens and transmitting the optical signal to the integrating sphere.
Furthermore, the signal channel system comprises a second optical fiber for receiving the signal light transmitted by the 45 ° reflector and transmitting the signal light to the signal port of the integrating sphere, and a signal shutter arranged at one end of the second optical fiber and coupled with the signal port.
Further, the signal channel system further comprises a second lens barrel and a second lens arranged in the second lens barrel; the second optical fiber receives the optical fiber output by the second lens and transmits the optical fiber to the integrating sphere.
Further, the working distance range of the outer ball type diffuse reflection spectrum measuring device is f-2 f, wherein f is the focal length of the polarization component;
the optimal working distance range of the outer ball type diffuse reflection spectrum measuring device is as follows:
wherein R is the cross-sectional radius of the second optical channel, R is the cross-sectional radius of the first optical channel, and f is the focal length of the polarization assembly.
Compared with the prior art, the external sphere type diffuse reflection spectrum measuring device has the beneficial effects that: the signal to noise ratio is improved, and the signal level is further maximized by designing the optimal working distance, so that the time required by full spectrum acquisition and data analysis is greatly reduced, the measurement efficiency is improved, and the method has strong online application adaptability in a wide field; the optimal working distance used in cooperation with the device is provided, the using effect is greatly improved, the optimal signal-to-noise ratio is achieved, and the measuring efficiency is improved.
[ description of the drawings ]
FIG. 1 is a schematic illustration of a light beam that produces a diffuse reflectance spectrum of an illuminated sample;
FIG. 2 is a schematic structural diagram of an embodiment of the present invention;
FIG. 3 is another schematic structural diagram of an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of an optimal working distance design according to an embodiment of the present invention;
FIG. 5 is a simplified schematic diagram of an optimal working distance design according to an embodiment of the present invention.
[ detailed description ] embodiments
Example (b):
diffuse reflectance near infrared spectroscopy is a technique for collecting and analyzing scattered near infrared energy, which, like diffuse reflectance, penetrates a sample on a nanometer scale and interacts with the sample. Fig. 1 shows a simplified schematic diagram assuming that the sample 14 is thick enough so that light does not pass through the sample 14. When incident light 10 illuminates a sample 14 having a rough surface, a portion of the light of each individual incident ray follows the law of reflection to produce specular reflection 11 in the expected angle of principal reflection; another portion of each individual incident ray is reflected at all possible angles and directions to produce a diffuse reflection 12. The degree or magnitude of the diffuse reflection 12 depends on the nature of the reflecting substance and the surface. Since near infrared light (NIR) is very transmissive to many materials, incident light 10 necessarily interacts with the material on the inside of the sample 14 to produce diffuse reflectance. The general mechanism for producing diffuse reflection does not involve the surface completely, most of the light is contributed by scattering centers below the surface, and the main interactions include scattering and absorption; the scattering effect is determined by the size and orientation of these scattering centers, while the absorption is significantly affected by the percentage of certain components in the sample 14.
Referring to fig. 1-5, the present embodiment is an external-sphere type diffuse reflection spectrum measuring apparatus, which includes a light source 20 capable of emitting near infrared light, a first optical system for transmitting light emitted from the light source 20 to a sample surface 13, a second optical system for transmitting light emitted from the light source 20 to a reference channel system, collecting diffuse reflection light from the sample surface 13, and transmitting the collected diffuse reflection light to a signal channel system, an integrating sphere 30 for receiving optical signals transmitted from the reference channel system and the signal channel system, and a spectrum analyzer 40 connected to an output end of the integrating sphere through a third optical fiber 34.
The first optical path system comprises a shell 16 enclosing a light source 20, the shell 16 comprises a light reflection arc surface 161 which is positioned at the top and emits light emitted by the light source 20 in a cylindrical alignment manner, and a cylinder 163 formed with a first optical channel 162, part of the light emitted by the light source 20 passes through the light reflection arc surface 161 to form cylindrical alignment light, and the cylindrical alignment light is emitted through the first optical channel 162, and a light polarization assembly 21 and an exit window 22 are sequentially arranged at the exit window of the first optical channel 162 along the light beam direction. The light deflecting unit 21 may be a hollow fresnel lens or a ring-shaped optical glass lens, and is mainly used to focus the cylindrical collimated light beam formed through the light reflection arc surface 161 on the sample surface 13. The exit window 22 may employ an optical lens having a focusing function. The light reflection arc 161 is formed as a reflector.
The light source 20 may be a single light source or a plurality of LED lamps having different outputs of near infrared wavelength. The light source 20 may comprise a broad spectrum NIR light source to allow NIR light energy output coupled to the first optical path. The wavelength of the light source 20 is an effective wavelength for analysis in a range of 780nm to 2500 nm.
The light reflection arc 161 is usually implemented by a parabolic reflector, and may be made of aluminum alloy or aluminum-plated.
The cylinder 163 is preferably a metal cylinder, and may be made of aluminum alloy or stainless steel, and is black-oxidized, mainly for limiting light and dissipating heat.
The second optical system comprises a second optical channel 17 which is arranged in the center of the first optical channel 162 in parallel and penetrates through the polarization assembly 21, and a 45-degree reflector 23 which is positioned above the second optical channel 17, wherein the second optical channel 17 is positioned right below the light source 20, the 45-degree reflector 23 is positioned between the light source 20 and the second optical channel 17, and the 45-degree reflector 23, the signal channel system and the reference channel system are positioned on the same optical horizontal line. The second optical channel 17 is arranged extending upwards from the upper surface of the exit window 22. The second optical channel 17 is arranged coaxially with the first optical channel 162.
The projection area of the 45 deg. mirror 23 matches the cross section of the second optical channel 17. The 45 deg. mirror 23 is not meant to have to be mounted at an angle of 45 deg. to the central axis of the second optical channel 17, it may be positioned at other angles around 45 deg.. For ease of use, 45 ° is a preferred arrangement. The side surface of the 45 deg. mirror 23 facing the light source 20 is provided with a coating of a highly reflective material, for example BaSO4Zenith Polymer and Spectralon, which are ideal diffuse reflective materials that directly reflect a portion of the light emitted from the light source 20Into the reference channel system. The surface of the side of the 45 deg. mirror 23 facing the second optical channel 17 (the back side abutting the light source 20) is coated with an infrared reflective coating to achieve specular reflection of the signal.
Referring to fig. 2, the light deflecting assembly 21 is disposed directly above the exit window 22 from the inside of the cylinder 163, and the light deflecting assembly 21 may be a fresnel lens or an annular optical glass lens, and is mainly used for converging the exiting light to irradiate the sample surface at an incident angle in a specific range, and maximally excluding the specular reflection light from entering the second optical channel 17, and this arrangement eliminates the advantage that the specular reflection light is mixed into the signal light from the second optical channel 17, so that the light entering the second optical channel 17 is a very pure signal light carrying material component information, thereby greatly improving the signal-to-noise ratio.
The reference channel system is mainly used for measuring a reference spectrum of a white standard material, and comprises a first lens barrel 14 fixed on a housing 16, a first lens 24 arranged in the first lens barrel 14, a first optical fiber 26 for receiving light output by the first lens 24 and transmitting the light into a reference port 32 of an integrating sphere 30, and a reference shutter 28 arranged at the other end of the first optical fiber 26 and coupled with the reference port 32. More light is transmitted into the first optical fiber 26 by mounting the first lens 24. When the reference light is strong enough, the first lens 24 may not be needed. The first optical fiber 26 has one end connected to the first barrel 14, and if the first barrel 14 is not in place, may be directly connected to the housing 16, and has the other end connected to the reference shutter 28. Reference shutter 28 controls a reference input into integrating sphere 30 through reference port 32 in the time domain, providing a switching function.
The signal channel system is mainly used for measuring signals and comprises a second lens barrel 15 fixed on a shell 16, a second lens 25 arranged in the second lens barrel 15, a second optical fiber 27 receiving an optical fiber output by the second lens 25 and transmitting the optical fiber to an integrating sphere 30 and a signal port 31, and a signal shutter 29 arranged at the other end of the second optical fiber 27 and coupled with the signal port 31. More signal light is transmitted into the second optical fiber 27 by installing the second lens 25. When the signal light is strong enough, the second lens 25 is not necessary. One end of the second optical fiber 27 is connected to the second barrel 15, and if the second barrel 15 is not in place, the second optical fiber 27 may be directly connected to the housing 16 and the other end connected to the signal shutter 29. The signal shutter 29 controls a signal input to the integrating sphere 30 through a signal port 31 in a time domain, providing a switching function. In case the signal light is not strong enough, the second lens 25 helps to transfer most of the signal light to obtain a higher signal-to-noise ratio.
Integrating sphere 30 is connected to a spectrum analyzer 40 through a third optical fiber 34 through an outlet 33. Integrating sphere 30 has two inlets, signal port 31 and reference port 32, and an outlet, outlet 33.
Referring to fig. 3, in another embodiment, the signal channel is upgraded by directly coupling the second lens 25 in the second barrel 15 into the signal port 31 of the integrating sphere 30, as shown in fig. 3. The advantage of this arrangement is that almost all of the signal light is coupled into integrating sphere 30 so that near infrared spectra have a higher signal-to-noise ratio and spectrum acquisition can be made faster in the case of online or offline measurements. The signal shutter 29 controls a signal input to the integrating sphere 30 through a signal port 31 in a time domain.
In the embodiment, the 45 ° reflector 23 is arranged right above the second optical channel 17, so that the columnar collimated light reflected by the light reflection arc surface 161 is effectively prevented from entering the second optical channel 17, the purity of the signal light in the second optical channel 17 is improved, and the signal-to-noise ratio is improved; and on the other hand, the 45 ° reflector 23 is used to receive the cylindrical collimated light reflected by the partial light reflection arc surface 161, and the full mirror surface is reflected into the reference channel system, so as to provide the measurement data of the reference light.
In general, for both configurations described in fig. 2 and 3, the exposed area on the sample surface 13 can be characterized by an annulus that becomes smaller and smaller until a point is reached where the working distance is equal to the focal length (f) of the exit window 22. The working distance of the external sphere type diffuse reflection spectrum measuring device of the embodiment is f-2 f, that is, the distance between the surface of the sample and the lower surface of the polarization assembly 21 is f-2 f. If the working distance is less than f, there may be specular reflection in the second optical channel 17; if the working distance is too far, greater than 2f, the light becomes too diffuse and there is not enough light to illuminate the sample surface directly below the second optical channel 17.
As shown in fig. 4-5, to demonstrate how the optimal working distance can be set to achieve a better signal-to-noise ratio. Assuming that the radius of the cross section of the second optical channel 17 is R, the radius of the cross section of the housing 16 is R, and the focal length of the polarization assembly 21 is f, the optimal working distance d can be calculated by the following formula0：
Then the process of the first step is carried out,
we assume that the ideal working distance interval is [ d ]0-Δ,d0+Δ]Wherein Δ is at d0And f is a position between
The optimal working distance range that can be calculated is:
as shown by the gray shading in fig. 4, the upper limit value and the lower limit value in the above-mentioned optimum working distance range are subtracted to obtain:
it follows that the size of the optimum working distance range is determined by the two mutually independent radii and focal lengths.
An external sphere type diffuse reflection spectrum measuring apparatus of the present embodiment provides a light source 20, which light source 20 emits an illumination beam through a first optical system and is condensed by an optical element to illuminate a sample surface 13. Light from the light source 20 is collimated by the parabolic reflector (i.e., the light ray reflection arc 161); collimated light is condensed by the polarizing assembly 21; the light source 20 is located inside the housing 16 and the second optical channel 17 is located at the central axis of the housing 16. At a set position close to the light source 20 or the light-gathering polarization assembly 21, a 45 ° reflector 23 with a high-reflection material coating is placed on the central axis at an angle of 45 degrees with respect to the central axis of the first optical channel 162 and above the second optical channel 17, and a part of the light source 20 is transmitted into the reference channel system by using the side of the 45 ° reflector 23 coated with the high-reflection material coating, transmitted to the reference port 32 through the first optical fiber 26, and input into the integrating sphere 30. The housing 16 itself has good heat dissipation properties and a heat sink can be mounted behind the light source 20 to dissipate excess heat when more heat needs to be dissipated.
After collimated light is focused by the polarization assembly 21 and then irradiates the surface of the sample, specular reflection and diffuse reflection light generated from the surface of the sample enters the second optical channel 17, is transmitted into the signal channel system through the 45 ° mirror 23 above the second optical channel 17, is transmitted to the signal port 31 through the second optical fiber 27, and is input into the integrating sphere 30.
The light source 20 emits collimated light, a first part of which is reflected by a 45 ° mirror 23 to the side facing the light source and collected by an integrating sphere, the 45 ° mirror 23 being coated on its back with a highly reflective material, the light collected and measured through the light path being used as white background data or a so-called reference; a second portion of the light illuminates the sample and carries signal information and enters second optical channel 17, after which second optical channel 17 the signal light is reflected by the other side of 45 ° mirror 23 and collected by integrating sphere 30. The entry of the signal and the reference of the integrating sphere are gated separately by shutters and can be measured at different times, as required, by a spectrometer optically connected to the integrating sphere. Any type of spectrometer can be used to separate the light into specific wavelengths and record the spectra, such as a grating-based system or an interferometer-based system.
In a preferred embodiment, the reference light is transmitted into the integrating sphere through an optical fiber or a fiber bundle, and if the brightness is too low, a lens may be disposed in front of the collecting end; the lens is placed at a suitable distance from the collection end of the fiber so that it focuses enough light into the fiber, but not too close to the focal point, as it could cause overheating of the fiber.
In practical applications, near infrared spectrometers need to be moved from laboratory applications to more environmentally complex production lines, and thus high quality signal light, i.e. higher signal-to-noise ratio, is required. A high signal-to-noise ratio generally means more signal light and less noise or other uncorrelated light. The invention provides an innovative device for optimizing a light path and a method for calculating an optimal working distance so as to improve the quality of signal light. The invention is particularly suitable for industrial on-line application requiring real-time monitoring.
The outer sphere type diffuse reflection spectrum measuring device improves the signal-to-noise ratio, further maximizes the signal level by designing the optimal working distance, greatly reduces the time required by full spectrum acquisition and data analysis, improves the measuring efficiency, and has strong online application adaptability in a wide field.
What has been described above are merely some embodiments of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept thereof, and these changes and modifications can be made without departing from the spirit and scope of the invention.
Claims (10)
1. An outer sphere type diffuse reflection spectrum measuring device is characterized in that: the optical spectrum analyzer comprises a light source capable of emitting near infrared light, a first optical system for transmitting a part of light emitted by the light source to a sample surface, a second optical system for transmitting a part of light emitted by the light source to a reference channel system, collecting diffuse reflection light from the sample surface and transmitting the diffuse reflection light to a signal channel system, an integrating sphere for receiving optical signals transmitted by the reference channel system and the signal channel system according to a time domain sequence, and a spectrum analyzer connected with the output end of the integrating sphere through a third optical fiber.
2. The exosphere-type diffuse reflectance spectrum measuring device according to claim 1, wherein: the first light path system comprises a shell enclosing the light source, the shell comprises a light reflection arc surface and a barrel, the light reflection arc surface is positioned at the top and enables light emitted by the light source to be emitted in a cylindrical alignment mode, the barrel is provided with a first optical channel, and part of light emitted by the light source passes through the light reflection arc surface to form cylindrical alignment light and is emitted through the first optical channel; and a polarizing component and an exit window are sequentially arranged at the exit window of the first optical channel along the light beam direction.
3. The exosphere-type diffuse reflectance spectrum measuring device according to claim 2, wherein: the second optical system comprises a second optical channel which is arranged in the center of the first optical channel in parallel and penetrates through the polarization assembly, and a 45-degree reflector positioned above the second optical channel, the second optical channel is positioned right below the light source, the 45-degree reflector is positioned between the light source and the second optical channel, and an optical bus of the 45-degree reflector is positioned on the same optical horizontal line with the signal channel system and the reference channel system;
the signal channel system comprises a second lens barrel and a second lens which is arranged in the second lens barrel and is directly coupled with a signal port of the integrating sphere.
4. The exosphere-type diffuse reflectance spectrum measuring device according to claim 3, wherein: the second optical channel extends upwards from the upper surface of the emergent window; the second optical channel is disposed coaxially with the first optical channel.
5. The exosphere-type diffuse reflectance spectrum measuring device according to claim 3, wherein: a high-reflection material coating is arranged on the surface of one side, facing the light source, of the 45-degree reflector; and the surface of one side of the 45-degree reflector facing the second optical channel is coated with an infrared reflection coating.
6. The exosphere-type diffuse reflectance spectrum measuring device according to claim 3, wherein: the reference channel system comprises a first optical fiber and a reference shutter, wherein the first optical fiber receives the reference light transmitted by the 45-degree reflector and transmits the reference light to a reference port of the integrating sphere, and the reference shutter is arranged at one end of the first optical fiber and coupled with the reference port.
7. The exosphere-type diffuse reflectance spectrum measuring device according to claim 6, wherein: the reference channel system further comprises a first lens barrel and a first lens arranged in the first lens barrel, wherein the other end of the first optical fiber is connected to the first lens barrel and used for receiving an optical signal output by the first lens and transmitting the optical signal to the integrating sphere.
8. The exosphere-type diffuse reflectance spectrum measuring device according to claim 3, wherein: the signal channel system comprises a second optical fiber and a signal shutter, wherein the second optical fiber receives the signal light transmitted by the 45-degree reflector and transmits the signal light to the signal port of the integrating sphere, and the signal shutter is arranged at one end of the second optical fiber and coupled with the signal port.
9. The exosphere-type diffuse reflectance spectrum measuring device according to claim 8, wherein: the signal channel system further comprises a second lens barrel and a second lens arranged in the second lens barrel; the second optical fiber receives the optical fiber output by the second lens and transmits the optical fiber to the integrating sphere.
10. The exosphere-type diffuse reflectance spectrum measuring device according to claim 1, wherein: the working distance range of the outer ball type diffuse reflection spectrum measuring device isf ~2 fWhereinfIs the focal length of the polarizing component;
the optimal working distance range of the outer ball type diffuse reflection spectrum measuring device is as follows:
wherein,ris the cross-sectional radius of the second optical channel,Ris the cross-sectional radius of the first optical channel,fis the focal length of the polarizing component.
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| CN202110358136.XA CN112945857A (en) | 2021-04-01 | 2021-04-01 | Outer ball type diffuse reflection spectrum measuring device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114777919A (en) * | 2022-04-14 | 2022-07-22 | 北京市农林科学院 | Light path structure for collecting diffuse transmission light signals |
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