Spectrophotometer

Abstract

The invention relates to the field of optical instruments and is intended for scientific research purposes in the analysis of industrial laboratories and in the analytical study of the spectral properties of various materials. The technical result is an improvement in the quality and accuracy of angular correlation measurements and complex prism measurements. A spectrophotometer comprises a housing (1), a measuring compartment (2) and a monochromatic radiation source (3), in which are installed: a radiation source (4); a monochromator (5); a polarizer assembly (6); a reflector element (7); a measurement channel having an assembly (8) of a photodetector (12) and a lens (13); a reference channel having an assembly (9) of a photodetector (14) and a lens (15); a rotating object stage (10) having a hollow rotation axis (16) and a sample (11); and means for moving the assembly (8) of the measurement channel of the photodetector (12) using a vertical rotation axis (17). When performing a measurement, the rotating object stage (10) of the spectrophotometer is capable of providing three exposures of the sample (11).

Description

Technical Field

[0001] The invention relates to the field of optical instruments and is intended for analysis in industrial laboratories and for scientific research purposes in analytical studies of the spectroscopic properties of various materials. Background Art

[0002] From the prior art, various types of spectrophotometers are known that are structurally composed of optical-mechanical and electronic components installed in a housing, and their general operating principle is based on measuring the ratio of the intensity of the radiation that has passed through the object under investigation to the intensity of the radiation that has not passed through the object. Usually, the device is also equipped with accessories [1,2,3].

[0003] The Cary 7000 spectrophotometer [1] is equipped with an additional two-stage detector that has the ability to move around the sample and is placed in the center of the accessory on a 360-degree rotating stage. The accessory can also provide reflectance measurements and can be used as a fiber optic probe or for other purposes.

[0004] The Agilent Cary 60 spectrophotometer [2] is equipped with a Czerny-Turner type monochromator and has an operating wavelength range of 190-1100 nm, with a fixed wavelength band of 1.5 nm. The Cary 60 design uses paired Si diode detectors and quartz coated optics, it provides spectral scan speeds up to 24,000 nm / min, data sampling rates up to 80 times per second, the device allows wavelength tuning when the measurement is paused and it is insensitive to ambient light. The Agilent Cary 60 is centrally controlled using a Windows PC.

[0005] The well-known single-beam spectrophotometer SF-56 [3] from the UVI range allows automatic single and multiple measurements of the spectral transmittance of liquid and solid transparent substances of one or more samples at a wavelength specified by the operator, with specified time intervals between measurement cycles, overview scanning and output of specified parts of the spectrum on a video monitor for qualitative analysis, kinetic measurements and mathematical processing of the measurement results, including calculation of optical density and concentration, as well as calculation of the color characteristics of the object under investigation. The spectrophotometer is controlled and the measurement results processed using a dedicated controller with functional keyboard, display and printer, or using an external IBM-compatible computer.

[0006] A disadvantage of known similar solutions is the limited ability to move the sample on the object stage during the measurement, which, therefore, reduces the functionality of the device and excludes the possibility of measuring the transmission or reflection of the sample radiation without the use of special accessories.

[0007] There is a known spectrophotometer having a movable optical element [4]. The spectrophotometer includes a filter for removing high-order light as such an element and in such a manner that it is driven by a drive mechanism for rotating a diffraction grating without requiring a special drive. A control circuit for the filter or other device, which serves as a mechanism for removable insertion in an optical path, is implemented by using dedicated software. The mechanism has a drive rod integrated with a spectrometer diffraction grating and rotated by the diffraction grating. A driven arm is used to support the optical element, and its position can separate the optical path. The drive rod is located at a position contacting the drive arm within a pivot angle range outside the wavelength pivot range, scanning the diffraction grating. The drive rod is configured to be driven by contacting the drive arm and to be displaced to move the optical element between a position on the optical path and a position outside the optical path.

[0008] A disadvantage of similar schemes is the limited freedom of sample movement provided by the control circuitry of the filters and other devices acting as a mechanism for removable inserts in the optical path.

[0009] The spectrophotometer with two-beam splitting adopted as a prototype [5] is closest to the current invention. The beam splitting device of the spectrophotometer comprises a housing with a measuring compartment, in which an optical system with a reflective component is installed, a motor, a rotating shaft, and the rotating shaft is made to be able to perform an additional rotation relative to the center of the rotating shaft. The optical system includes a radiation source, a monochromator, a reflector element for splitting the light beam emitted by the monochromator into a measuring channel with a photodetector assembly and a reference channel with a photodetector assembly, and a set of devices placed on a rotating object stage for moving the sample during measurement. In this case, the rotating object stage is equipped with three structures; the first structure is a transparent component intended for direct passage of the light beam, the second structure is a reflective component for reflecting the light beam, and the third structure is designed as a dark component for blocking the light beam and absorbing the light beam. The transparent part, the reflective part and the dark part are distributed around the circumference in a predetermined order. The rotating disk also contains a rotating element rotating around the center of the rotating shaft. The rotating element is equipped with a through hole or a recess for measuring the rotation period. The rotation period is determined by the number of through holes or recesses and the number of rotation periods. The through hole openings or recesses are evenly distributed along the edge of the rotating part, and further include a photoelectric switch, which is equipped with a groove made into the edge of the rotating part, and receives a photosensitive receiving and emitting source on both sides of the rotating part accordingly. The photosensitive receiving part and the emitting part of the light source are respectively located on both sides of the groove wall relatively, and are configured to determine the rotation period of the through hole or recess. The motor is connected to the rotating shaft, and the rotating element and the rotating wheel can rotate, and provide synchronous rotation at a given speed through the rotating shaft. The reflecting part includes a first reflector, a second reflector, and a third reflector, which are respectively located on the front and rear sides of the rotating object stage. The first reflector and the third reflector are located on the same side of the rotating object stage, and the first reflector is used to reflect the light beam to the rotating object stage, and the light beam reflected from the first reflector forms a reference beam with a predetermined order by transmitting a portion of the light beam to the second reflector. The light beam reflected by the first reflector forms a sampling beam with a predetermined order through the reflecting part and the third reflector. And the light beam reflected by the first reflector is absorbed by the dark part and forms an occlusal beam with a predetermined order. The first structure of the rotating object stage is a transparent part through which the light beam passes directly. The second structure is a part that reflects the light beam. And the third structure is designed to block the light beam and absorb its tempo part. The transparent parts, reflective parts and dark parts are distributed on a circle on the rotating object stage in a predetermined order, and the transparent parts, reflective parts and dark parts are arranged in pairs and symmetrically.

[0010] The disadvantage of the prototype is the limitation of the ability to measure the investigated sample due to the movement of the rotating object stage in one plane, which reduces the correctness of the measurement behavior. Summary of the invention

[0011] The purpose of the invention is to improve the performance and measurement accuracy of the samples under study.

[0012] A technical effect of the invention is to improve the quality and accuracy of angle dependency measurements and measurements of complex prisms, regardless of the thickness of the component or the geometric complexity of the prism.

[0013] The technical effect is achieved by the fact that in a spectrophotometer comprising a housing in which the measuring compartment and the monochromatic radiation source are located, the spectrophotometer comprises: a radiation source; a monochromator; a polarizer assembly; a reflector element which separates the light beam coming out of the monochromator into a measuring channel with a varying assembly for a photodetector, a reference channel with a varying assembly for a photodetector and a lens; a rotating object stage with a sample for measurement; according to the invention, the rotating object stage is made to provide the possibility of three exposures of the sample during the measurement, in which case the rotating object stage is designed to rotate around itself The rotating axis rotates clockwise or counterclockwise until the end face of the sample intersects with the light beam coming out of the monochromator, and the measurement channel assembly is configured to rotate clockwise or counterclockwise around the rotating axis of the rotating object stage until the moment of intersecting with the light beam coming out of the monochromator, and at the same time the measurement channel assembly of the photodetector independently rotates clockwise or counterclockwise around its rotating axis until the moment of intersecting with the light beam entering the lens of the photodetector in the measurement channel, ensuring that the light beam received into the lens of the photodetector and the light beam passing through the sample being measured or the light beam reflected from the sample being measured is accurately along the normal line, regardless of whether there is a beam displacement.

[0014] The assembly of photodetectors of a measuring channel is made of one or more photodetectors.

[0015] The assembly of the photodetector of the reference channel is made of one or more photodetectors.

[0016] The rotation axis of the rotating object stage is central and a power supply cable can be laid through the hollow to remotely control the rotation of the rotating object stage and the movement of the sample relative to the light beam coming out of the monochromator without opening the measurement compartment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The essence of the present invention is Figure 1-3 As shown in the accompanying drawings.

[0018] Figure 1 A basic optical diagram of a spectrophotometer is shown.

[0019] Figure 2 The components of the photodetector of the measurement channel are shown.

[0020] Figure 3 The components of the photodetector of the reference channel are shown. DETAILED DESCRIPTION

[0021] The spectrophotometer comprises a housing (1), a measuring compartment (2) and a monochromatic radiation source (3), wherein the radiation source (4), a monochromator (5), a polarizer assembly (6), a reflector element (7), a measuring channel having an assembly (8) of a photodetector (12) and a lens (13), a reference channel having an assembly (9) of a photodetector (14) and a lens (15); a rotating object stage (10) having a hollow rotating axis (16) and a sample (11); and a device for installing the assembly (8) of the measuring channel for moving the photodetector (12) by rotating a vertical axis (17).

[0022] The spectrophotometer is operated in the following manner. The device is turned on and made ready for use according to the instructions. For the measurement, a sample 11 is placed beforehand on a rotating object stage 10 in the measuring compartment 3 in the housing 1. The sample 11 is fixed and the measuring compartment 2 is closed. During the measurement, three exposures of the sample 11 are provided. For this purpose, the rotating object stage 10 with the sample 11 is rotated clockwise or counterclockwise around the axis 16 until the end face of the sample 11 intersects the light beam coming out of the light source 4 and then passes through the polarizer 6 and leaves the monochromator 5, while a part of the light flux is guided by the mirror element 7 into the lens 15 to the photodetector 14 of the component 9 of the reference channel, and another part of the light flux is guided to the sample 11 and after transmission or reflection of the light beam, it enters the measuring channel through the lens 13 into the photodetector 12 of the component 8. At the same time, the component 8 with the photodetector 12 rotates clockwise or counterclockwise around the vertical rotation axis 17 until it intersects the light beam entering the lens 13 on the photodetector 12, and the component 8 with the photodetector 12 rotates independently around the rotation axis 16 of the rotating object stage 10, receiving the light beam into the lens 13 of the photodetector 12, and the light beam passing through the sample under test 11 or reflected from the sample under test 11 is accurately along the normal line, regardless of whether there is a beam displacement.

[0023] The rotating object stage 10 is mounted on a rotating shaft 16 which is hollow (not shown in the figure) so that a cable (not shown in the figure) can be laid through the cavity of the shaft 16 and the rotating object stage 10 with the sample 11 can be remotely controlled with respect to the light beam coming out of the monochromator 5 without opening the measuring compartment 2. In addition, the spectrophotometer is equipped with a set of rotating object stages 10 which are variable and have an electric drive (not shown in the figure). The rotating object stage 10 has a matching electrical connector (not shown in the figure) which is mounted in a matching part of a component for mounting it (for example, in the form of a dovetail). When the electric rotating object stage 10 is mounted via the electrical connector, power can be supplied to the circuit of the control board with the controller and the computer remote control of the rotating object stage 10 without opening the measuring compartment 2.

[0024] In the housing (not shown in the figure) of the component 8 with the photodetector 12 of the measurement channel and the component 9 with the photodetector 14 of the reference channel, multiple groups of photodetectors 12 and 14 (in various combinations, such as РМТ, Si, InGaAs, PbS, PbSe, МСТ, etc., from 1 to 4 pieces) and a mechanism (not shown in the figure) for automatically positioning the photodetectors 12 and 14 on the beam axis are installed, which are used according to the required spectral range of measurement.

[0025] The implementation of three exposures of the sample 11 during the measurement, due to the combination of a corresponding rotation of the assembly 8 with the photodetector 12 and a rotation of the rotating object stage 10, ensures the achievement of the claimed technical effect and, therefore, improves the quality and accuracy of the angular dependence and polarization measurements of transmission and reflection, as well as the measurement of complex prisms, regardless of the thickness of the sample or the geometrical complexity of the prism.

[0026] References:

[0027] 1. New Universal Spectrophotometer Cary 7000. ALSI-CHROM LLC, http: / / www.alsichrom.com,

[0028] 2. Spectrophotometer Agilent Cary 60. North House Business Center, Millab, www.millab.ru, 2018.

[0029] 3. UVI Spectrophotometer SF-56. OKB SPEKTR LLC, http: / / ok.b-spectr.ru / products / sf / sf56 / , 2018.

[0030] 4.JP No.2010160025(А),22.07.2010.

[0031] 5. CN No.107796514(A), November 24, 2017 (prototype).

Claims

1. A spectrophotometer comprising: A housing (1), wherein the housing (1) comprises a measuring compartment (2) and a monochromatic radiation source (3), wherein the monochromatic radiation source (3) comprises a radiation source (4), a monochromator (5), a polarizer assembly (6), a measurement channel (8) having an assembly of a lens (13) and a photodetector (12), a reference channel (9) having an assembly of a lens (15) and a photodetector (14), a reflector element (7) configured to split the light beam from the monochromator (5) into a measurement channel (8) and a reference channel (9), and a rotating object stage (10) having a sample (11) for measurement, wherein the rotating object stage (10) is configured to provide exposure of the sample (11) during measurement, The rotating object stage (10) is configured to rotate clockwise or counterclockwise around its own rotation axis (16) until the end face of the sample (11) intersects the light beam coming out of the monochromator (5). wherein the measuring channel (8) is configured to rotate clockwise or counterclockwise around the rotation axis (16) of the rotating object stage (10) until the moment of intersecting the light beam coming out of the monochromator (5); and The measuring channel (8) has an additional rotation axis (17) oriented parallel to the rotation axis (16) of the rotating object stage (10), the additional rotation axis (17) being different from the rotation axis (16) of the rotating object stage (10), and the measuring channel (8) is configured to rotate clockwise or counterclockwise around the additional rotation axis (17) independently of the rotation around the rotation axis (16) of the rotating object stage (10) until the moment of intersection with the light beam entering the lens (13) and the photodetector (12) of the measuring channel (8), thereby ensuring that the light beam is received into the lens (13) and the photodetector (12) of the measuring channel (8) and the light beam passes through the measured sample (11) or is reflected from the measured sample (11) accurately along the normal line, regardless of whether there is a beam displacement.

2. The spectrophotometer according to claim 1, characterized in that: The assembly of photodetectors (12) of the measuring channel (8) is made of one or more photodetectors (12).

3. The spectrophotometer according to claim 1, characterized in that: The assembly of the photodetector (14) of the reference channel (9) is made of one or more photodetectors (14).

4. The spectrophotometer according to claim 1, characterized in that: The rotation axis (16) of the rotating object stage (10) is hollow, through which cables can be routed to provide remote control of the rotation of the rotating object stage (10) and the movement of the sample (11) relative to the light beam leaving the monochromator (5), without opening the measurement compartment (2).

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