SU1430902A1 - Optical radiation spectrometer - Google Patents

Abstract

The invention relates to the field of optical information processing and is intended for use in optoelectronic measurement technology. The purpose of the invention is to improve the accuracy and speed of the spectral analysis of the optical image sections, their arbitrary sequence and combination. The spectrometer contains a raster diaphragm 1 input, made in the form of a bundle of equal lengths of single-mode optical fibers, collimation lenses 2 and 3, made in the form of axiJomatical lenses, a diffraction grating 4, a block n of array photodetectors 5, a control and display block 6, which can contain a multiplexer unit 7 and a computer 8, an analyzing luminous transparency 9. In the prototype, different patterns of distribution of holes in the raster diaphragm correspond to different laws for reading information from image areas gmah. A change in the law of concurrence is achieved by replacing the standard, the time of which is far superior to the time of the process of analyzing and fixing the results. Synchronous recording of the image spectrum of the analyzed areas, provided by the introduction of a block of n matrix photodetectors, makes it possible to automate the connection of one or the other. another area, increasing the speed of the device compared to the prototype, 1 C.p. f-ly, 1 ill.

Description

The invention relates to an optical information processing apparatus and is intended for use in an optical electronic measurement technology.

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The purpose of the invention is to improve the accuracy and speed of the spectral analysis of the optical image sections, their arbitrary sequence and combination.

The drawing shows a block diagram of the device, 1 The device contains a raster diaphragm 1 input, imprinted in the form of a bundle n equal lengths of single-mode optical fibers, collimation objectives 2 and 3, made in the form of achromatic lenses, diffraction grating 4, block n matrix photodetectors 55 block 6 control and indication, which may contain, in particular, block 7 multiplexers and computer 8 "The drawing also shows the luminous transport being analyzed: grant 9.

The input ends of the fiber bundle 1 are aligned with the image areas on the transparency 9. The output fibers of the fiber are distributed over the surface of the collimation lens 2. The diffraction grating 4 is located between the collimation lens lenses 2 and 3. The block n matrix photodetectors 5, whose optical windows Oriented to the ends of the corresponding fiber p so that the first cell of each photodetector is located on the axis of the end of the corresponding fiber on the first lens, 2, is located in the output plane of the second lens 3. Outputs all photodetectors are connected to the control and display unit 6, in particular from the input t of the multiplexer 7 unit .7, the control input and the output of which are connected to the computer 8,

The optical radiation spectrometer operates as follows.

The image of the areas of the analyzed light of the object 9, combined with the entrance end of a certain segment of optical fiber with a raster diaphragm 1 is projected by an achromatic lens collimation lens 2 onto the diffraction grating 4, which is a spectral device that decomposes white light into a spectrum, each component with a wavelength A deviates into his

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diffraction angle cf. The second achromatic collimation lens objective 3 converts the angular diffraction 1: (ion spectrum / (tf)) into a spatial distribution along the axis perpendicular to the lines of the diffraction grating 4 on the input window of the corresponding matrix photodetector of the photodiode unit 5 of the photodetector in units of the wavelength (frequency) of light puts the number of each cell of the photodetector in a one-to-one correspondence with a certain optical frequency. photodetector cells with a central axis of the corresponding segment of the optical fiber ensures that the photodetector operates only on positive or only on negative diffraction peaks. The photodetector converts visible radiation into electrical signals and reads them sequentially at its own input, the output signal of the photodetector contains information about the cell number and its content, i.e., about a certain component of the image spectrum of a portion of the analyzed object 9, combined with the input end of The raster diaphragm 1 optical fiber section corresponding to this photodetector, the combination of n optical fiber lengths of diaphragm 1 and n matrix photodetectors 5 provides the outputs of the photodetectors of an aggregate of electrical signals corresponding to the spectrum of the entire open-surface diaphragm 1 of the object being analyzed 9,

To eliminate the intersection of rays from different fibers when exiting the diffraction grating 4 and expanding the frequency band, analyzing the distance between adjacent ends of the fibers in a direction perpendicular to the grating lines of the diffraction grating, choose a single photodetector in block 5, to eliminate optical mode astigmatism rays in fibers 1 they should be made of single-mode fiber. The number of fiber sections in the beam is determined by the conditions of the analysis task, by the presence of lenses 2 and 3 of sufficient diameter and can vary from one to the ratio of the area of the aperture of objective 2 to the doubled area of a single photodetector unit 5

The implementation of a raster diaphragm 1 in the form of a bundle of optical fiber segments when combining their ends with the analyzed image areas and the use of a single-mode fiber interferes with the mutual influence of the analyzed areas characteristic of the prototype and provides spectral analysis of individual image areas with a diameter of no more than 10 microns and the optical sampling frequency spectrum limited only by the period of the diffraction grating. Thus, it is possible to increase the accuracy of the spectral analysis of individual sections of the image. Electrical signals from the outputs of the photodetectors of the unit 5 are fed to the inputs of the control and display unit 6. It is a standard device consisting of a switch with an output follower, processing units, aiming and control. The switch provides a consistent connection of the signal from the photodetector cells to the output repeater. The information signal is processed by the processing units and by the NIN signal by the method of double correlated sampling. The operation of the receiver, processing units and signal extraction is controlled by the control unit,

In order to ensure simultaneous parallel operation of all n photodetectors, they can be combined along a chain of lines of transmission and erasure. The bit outputs of the photodetectors are connected respectively to the inputs of multiplexers 7, having n inputs and one output connected to the input of the computer 8. At the command of the computer, unit 7 of the multiplexers switches one of its inputs to its output or an arbitrary sequence of them. The next command loads the computer operating memory and then the information about the spectrum of the corresponding parts of the image is output to the display device (display, digital printer) or its processing is performed according to a known algorithm.

In the prototype, different laws for the distribution of holes in raster diaphragms correspond to different laws for viewing information from image areas. Change . The read-out law is achieved by replacing the standard, the time of which significantly exceeds the time of the process of analyzing and recording the results. Synchronous recording of the spectrum of images of the analyzed areas, provided by the introduction of a block of n matrix photodetectors, allows one to automate the connection of one or another section, increasing the speed of the device compared to the prototype.

Claims (2)

Invention Formula t 1, An optical radiation spectrometer containing an optically aligned sequence of a raster diaphragm input, a lens collimation lens, a diffraction grating and. matrix photodetector, the output of which is electrically connected to the control and display unit, characterized in that, in order to increase the accuracy and speed of the spectral analysis of any individual sections of the optical image or an arbitrary sequence and combination, the input aperture diaphragm is made in the form of a beam of n equal segments single-mode optical fibers, one end of which is combined with the areas of the analyzed image, and opposite are placed in the plane of the lens collimation volume made in the form of an achromatic lens, with a resolution of adjacent ends in the direction perpendicular to the grating lines of the diffraction grating, not less than the maximum size of the optical window of the photodetector, and a set of (n-1) matrix photoreceivers and the second achromatic lens are added, the input plane which is optically aligned with the output of the diffraction grating and placed at a distance from / it, providing a sweep of the diffraction spectrum throughout the photodetector window, and the output plane is aligned with a set of matrix photodetectors, the optical windows of which are oriented to the respective fiber ends, so that the first cell of each photodetector is located on the axis of the end of the corresponding fiber on the first lens, and the electrical outputs (p-1) of the photoelectric sensors are also connected to the control and display unit. 5 309026 2. The spectrometer according to claim 1, which is connected to the photo output so that it is in the control unit of the receiver, and the control input and the etching and display are additionally output from the computer. entered a file unit, inputs