Patent Description:
From the prior art, various types of spectrophotometers are known that structurally consist of optical-mechanical and electronic assemblies installed in one housing, and the general principle of their operation is based on measuring the ratio of the intensity of radiation that passed through the object under study to the intensity of radiation that did not pass through this object. Devices, as a rule, are additionally equipped with attachments [<NUM>, <NUM>, <NUM>].

The Cary <NUM> spectrophotometer [<NUM>] is equipped with an additional two-layer detector, which has the ability to move around the specimen, and which is placed in the center of the attachment on a <NUM>-degree rotary table. Attachments can also provide reflection measurements, and can be made as a fiber optic probe, or for other purposes.

The Agilent Cary <NUM> spectrophotometer [<NUM>] is equipped with a Czerny-Turner type monochromator and has an operating wavelength range of <NUM>-<NUM>, a fixed wavelength band of <NUM>. The design of the Cary <NUM> uses a paired Si diode detector and quartz-coated optics, it provides a spectrum sweep speed of up to <NUM>,<NUM>/min, a data sampling rate of up to <NUM> times per second, the device allows for wavelength tuning when measurements are paused and it is not sensitive to ambient light. The Agilent Cary <NUM> is centrally controlled using a Windows PC.

The well-known single-beam spectrophotometer of UVI range, SF-<NUM> [<NUM>], provides automatic single and multiple measurements of the spectral transmittance of liquid and solid transparent substances for one or more specimens at wavelengths specified by the operator, with a specified time interval between measurement cycles, overview scanning and output of specified sections of the spectrum on a video monitor for qualitative analysis, carrying out kinetic measurements and mathematical processing of the measurement results, including the calculation of optical density and concentration, as well as the calculation of the color characteristics of the objects under study. The spectrophotometer is controlled and the measurement results are processed using a specialized controller with a functional keyboard, monitor and printer, or using an external IBM-compatible computer.

The disadvantage of known analogs is the limited ability to move the specimens on the object table during measurements, which, as a result, reduces the functionality of the device and excludes the possibility of measuring transmission or reflection of radiation by a specimen without using special attachments.

There is a known spectrophotometer with a displaceable optical element [<NUM>]. The spectrophotometer contains an optical filter for removing light of a higher order as such an element and in such a way that it is driven by a drive mechanism for rotating the diffraction grating without the need for a special drive. The control circuit of the optical filter or of other devices, used as a mechanism for removable insert in the optical path, is implemented with the use of special software. The mechanism has a driving lever integrated with the spectrometer diffraction grating and rotated by the diffraction grating. A driven arm is used for supporting an optical element, located with a possibility to detach the optical path. The driving lever is located at a position contacting the drive arm in a pivot angle range outside the pivot range for wavelength, scanning the diffraction grating. The driving lever is configured to be driven by contact with the drive arm and is displaced to move the optical element between a position on the optical path and a position outside the optical path.

The disadvantage of the analog is the limited degrees of freedom of movement of the specimens provided by the control circuit of the optical filter and other devices used as a mechanism for a removable insert in the optical path.

A spectrophotometer with a two-beam splitting of an optical beam, which is adopted as a prototype [<NUM>], is closest to the current invention. The device for splitting the beam of the spectrophotometer contains a housing with a measuring compartment, where an optical system with a reflective part is installed, a motor, a rotary shaft made with the possibility of additional rotation relative to the center of the rotary shaft. The optical system includes a radiation source, a monochromator, a mirror element dividing the light beam coming out of the monochromator into a measuring channel with an assembly of photodetectors and a reference channel with an assembly of photodetectors, and a set of devices for moving specimens during measurements, placed on a rotary object table. In this case, the rotary object table is equipped with three structures; the first structure is intended for the light-transmitting part through which the light beam directly passes, the second structure is the reflective part of the reflected light beam, and the third structure is designed to block the light beam and absorb the dark part of the light beam. The light-transmitting portion, the reflective portion, and the dark part are distributed around the circumference in a predetermined order. The rotating disc additionally contains a rotating element that rotates about a center of the rotary shaft. The rotating element is provided with a measuring through hole or recess for a rotation period. The rotation period is determined by multiple through holes or recesses and a plurality of rotation periods. The throughway opening or recess is evenly distributed along the edge of the rotating part, additionally contains a photoelectric switch, which is provided with a groove built into the edge of the rotating part, and accordingly receives a photosensitive reception on both sides of the rotating element and a light-emitting source. The photosensitive receiving part and the emitting part of the light source, respectively, are located oppositely on both sides on the groove walls and are configured to determine the rotation period of the throughway opening or recess. The motor is connected to a rotary shaft with the possibility of rotation of the rotating element and the rotating wheel with the provision of synchronous rotation at a given speed through the rotary shaft. The reflective part contains a first mirror, a second mirror, and a third mirror, which are respectively located on the front and rear sides of the rotary object table. The first mirror and the third mirror are located on the same side of the rotary object table, with the first mirror being used to reflect the light beam towards the rotary object table, and the light beam reflected from the first mirror forming a reference light beam having a predetermined sequence by transmitting a portion of the light beam onto the second mirror. The beam reflected by the first mirror forms a sampling beam having a predetermined sequence through the reflective part and the third mirror. And the beam reflected by the first mirror is absorbed by the dark part and forms an occlusal beam having a predetermined sequence. The first structure of the rotary object table is a light-transmitting part through which the light beam directly passes. The second structure is a part of the reflected beam. And the third structure is designed to block the light beam and absorb its tempo part. Light-transmitting part, reflective part and dark part are distributed on a circle on the rotary object table in a predetermined order, while the light-transmitting part, the reflective part and the dark part are arranged in pairs and symmetrically.

The disadvantage of the prototype is the limited ability to measure the specimens under study due to the movement of the rotary object table in one plane, which reduces the correctness of the measurement behavior.

The research paper by <NPL> discloses a spectrophotometric device for analysing samples, such as multilayer dielectric gratings. The device comprises a bromine tungsten lamp B, a monochromator, an aperture A, a polariser assembly P, a collimator C, a beam splitter S configured to provide a measruring channel c and a reference chanel b. The reference channel comprises a focusing lens F<NUM> and a detector D<NUM>. The measuring channel comprises a rotary sample table R2 and a further rotary table R<NUM>, wherein the rotary tables have a common shaft. Rotary table R<NUM> is connected via an arm to a focusing lens F<NUM> and a detector D<NUM> of the measuring channel. Further, the paper discloses an application of measuring the reflected light from a tested sample, such as a diffraction grating.

The Japanese patent application <CIT> discloses a spectrophotometer to measure the light intensity transmitted through a sample or the light intensity reflected from the surface of the sample, and obtains the absorption spectrum or reflection spectrum of the sample, thereby analyzing optical characteristics of the sample. There are reference and sample measuring channels, a detector <NUM> with changeable position for measurement of the sample, and a detector of the main body A of the spectrophotometer is used as a reference detector. The sample stage <NUM> has a rotation center, and an arm <NUM> with the detector <NUM> rotates about the same rotation axis as the sample stage <NUM>. A photomultiplier tube is used as the detector. The light from the source is monochromatized and distributed to the sample and reference light beams by mirrors.

The Japanese utility model application<CIT>discloses a goniospectrophotometer for measuring the angle-dependent spectral reflection or transmission properties of an object by compensating for the polarization characteristics of an optical system. The object (sample) <NUM> reflects the illuminated light at an angle (<NUM>°) to the measuring channel (<NUM>, <NUM>, <NUM>), and the document discloses a solution for routine compensations (<NUM>) of polarization variances of the incident light to the sample <NUM>. The polarization of the incident light is made constant by the compensation means, thereby, enabling measurements of angle-dependent spectral reflectance/transmission properties of the object (<NUM>), being not influenced by variations of the polarization of the incident light.

The aims and technical solutions of the above discussed prior art documents, however, are different from those of the present invention.

The aim of the invention is to improve the performance and measurement accuracy of the specimens under study.

The technical result of the invention is to improve the quality and accuracy of angular dependence measurements and measurements of complex prisms, regardless of the thickness of the part or the geometric complexity of the prisms.

The technical result is achieved by the spectrophotometer according to independent claim <NUM>.

Further aspects of the invention are defined by the dependent claims.

The essence of the invention is illustrated in drawings in <FIG>.

The spectrophotometer contains a housing (<NUM>), a measuring compartment (<NUM>) and a source of monochromatic radiation (<NUM>), where a radiation source (<NUM>), a monochromator (<NUM>), an assembly of polarizers (<NUM>), a mirror element (<NUM>), a measuring channel with an assembly (<NUM>) of photodetectors (<NUM>) with a lens (<NUM>), a reference channel with an assembly (<NUM>) of photodetectors (<NUM>) with a lens (<NUM>); a rotary object table (<NUM>) with a hollow rotation shaft (<NUM>) and (<NUM>) specimens; devices for moving the assembly (<NUM>) of the measuring channel of the photodetectors (<NUM>) with a rotation vertical shaft (<NUM>) are installed.

The spectrophotometer operates in the following manner. In accordance with the instructions, turn on the device and bring it to readiness. To carry out measurements, in advance place a specimen <NUM> on the rotary object table <NUM> inside the measuring compartment <NUM> in the housing <NUM>. The specimen <NUM> is fixed and the measuring compartment is closed <NUM>. During measurements, a triple exposure of the specimen <NUM> is provided. For this, the rotary object table <NUM> with the specimen <NUM> is rotated around the shaft <NUM> clockwise or counterclockwise until the end face of the specimen <NUM> crosses the light beam coming out from the source <NUM> and then passes through the polarizer <NUM> and exits the monochromator <NUM>, while part of the light flux is directed by the mirror element <NUM> into the lens <NUM> to the photodetectors <NUM> of the assembly <NUM> of the reference channel, and the other part of the light flux is directed to the specimen <NUM> and after transmission or reflection of the light beam, it enters through the measuring channel through the lens <NUM> into the photodetectors <NUM> of the assembly <NUM>. Simultaneously, the assembly <NUM> with the photodetectors <NUM> is rotated around the vertical rotation shaft <NUM> clockwise or counterclockwise until it intersects with the beam entering the lens <NUM> on the photodetectors <NUM> and the independent rotation of the assembly <NUM> with the photodetectors <NUM> around the rotation shaft <NUM> of the rotary object table <NUM> with receiving a light beam into the lens <NUM> of the photodetectors <NUM> and passing through the measured specimen <NUM> or reflected from the measured specimen <NUM> light beam exactly along the normal with or without displacement of the light beam.

The rotary object table <NUM> is mounted on the rotation shaft <NUM>, which is hollow (not shown in the drawing) in such a way to make it possible to lay power cable (not shown in the drawing) through the cavity of the shaft <NUM> and control remotely the rotary object table <NUM> with the specimen <NUM> relative to the beam light coming out of the monochromator <NUM> without opening the measuring compartment <NUM>. Also, the spectrophotometer is equipped with a set of rotary object tables <NUM>, which are replaceable and with motorized drives (not shown in the drawing). The rotary object table <NUM> has a mating electrical connector (not shown in the drawing), which is installed in the mating part of the assembly for its installation (for example, in the form of a dovetail). When installing the motorized rotary object table <NUM> through the electrical connector, power is supplied to the electrical circuit of the control board with the controller and the computer remote control of the rotary object table <NUM> without opening the measuring compartment <NUM>.

Inside the housings (not shown in the drawing) of the assembly <NUM> with photodetectors <NUM> of the measuring channel and assembly <NUM> with photodetectors <NUM> of the reference channel, sets of photodetectors <NUM> and <NUM> are installed, respectively (from <NUM> to <NUM> pieces in various combinations, for example, PMT, Si, InGaAs, PbS, PbSe, MCT, etc., with and without cooling) and a mechanism (not shown in the drawing) for automatic positioning of the photodetectors <NUM> and <NUM> on the beam axis, which are used depending on the required spectral range of measurements.

Claim 1:
Spectrophotometer comprising
- a housing (<NUM>) wherein the housing (<NUM>) comprises a measuring compartment (<NUM>) and a source of monochromatic radiation (<NUM>), comprising a radiation source (<NUM>), a monochromator (<NUM>),
- an assembly of polarizers (<NUM>), a measuring channel (<NUM>) with an assembly of photodetectors (<NUM>) and a lens (<NUM>), a reference channel (<NUM>) with an assembly of photodetectors (<NUM>) and a lens (<NUM>),
- a mirror element (<NUM>) configured to divide the light beam coming out of the monochromator (<NUM>) into the measuring channel (<NUM>), the reference channel (<NUM>),
- a rotary object table (<NUM>) with a specimen (<NUM>) for measurements, wherein the rotary object table (<NUM>) is configured to provide an exposure of the specimen (<NUM>) during measurements, wherein
- the rotary object table (<NUM>) is configured to rotate around its own rotation shaft (<NUM>) clockwise or counterclockwise until the moment of intersection of the end face of specimen (<NUM>) with the light beam coming out from the monochromator (<NUM>), and
- the measuring channel (<NUM>) is configured to rotate around the rotation shaft (<NUM>) of the rotary object table (<NUM>) clockwise or counterclockwise until the moment of intersection with the light beam coming out from the monochromator (<NUM>),
characterized in that
the measuring channel (<NUM>) has a further rotation shaft (<NUM>) oriented in parallel to the shaft (<NUM>) of the rotary table (<NUM>), the further shaft (<NUM>) being different from the rotation shaft (<NUM>) of the rotary object table (<NUM>), and the measuring channel (<NUM>) assembly is configured to rotate around the further rotation shaft (<NUM>), independent from the rotation around the rotation shaft (<NUM>) of the rotary object table (<NUM>) clockwise or counterclockwise until the moment of intersection with the light beam entering the lens (<NUM>) of the photodetectors (<NUM>) of the measuring channel (<NUM>), thereby ensuring the reception of the light beam into the lens (<NUM>) of the photodetectors (<NUM>) and the light beam passing through the measured specimen (<NUM>) or reflected from the measured specimen (<NUM>) light beam exactly along the normal, with or without displacement of the light beam.