RU2621782C1 - Two-spectral optical system - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: two-spectral optical system comprises a main concave aspheric mirror with a central hole, a secondary convex aspheric mirror, a spectrum divider, a thermal channel with the first, the second and the third lenses, and the photodetecting device and the radiation flux switching device, two television channels with the lens and the photodetectors in each of the channels, and an information controlling and processing device. The outputs of the photodetecting devices of the thermal and two television channels are connected to the inputs of the information controlling and processing device, and the radiation flux switching device, conjugated with the first, the second and the third lenses of the thermal channel, is connected to the control output of the information controlling and processing device. The third lens of the thermal channel and the lens of the second television channel are configured to smoothly change the focal distance.

EFFECT: increasing the informativeness of the two-spectral optical system due to the additional information on the observed scene in the continually changing view angle.

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Description

The invention relates to the field of optoelectronic instrumentation and can be used in multichannel optoelectronic systems that provide search, detection and recognition of objects.

A compact optical-electronic device with one aperture and several radiation detectors is known (see US patent 6174061 B1, published January 16, 2001), containing a common channel consisting of a main concave aspherical mirror with a central hole, a secondary convex aspherical mirror, the first spectrometer with dichroic coating, transmitting radiation of the spectral range of 3 ... 5 microns and reflecting radiation of the spectral ranges of 0.7 ... 0.9 microns and 1.06 ... 1.54 microns, made in the form of an inclined plate and installed in a converging beam rays, as well as three channels for each of the spectral ranges. The channel of the spectral range of 3 ... 5 microns contains three lenses and a radiation receiver of the middle infrared range; the channel of the spectral range of 0.7 ... 0.9 μm contains nine lenses, a second spectrometer with a dichroic coating reflecting the radiation of the spectral range of 0.7 ... 0.9 μm and transmitting radiation of the spectral range of 1.06 ... 1.54 μm, and a radiation receiver near infrared range; the channel of the spectral range of 1.06 ... 1.54 microns contains an additional lens and a laser radiation receiver. The channel of the spectral range of 3 ... 5 μm, containing two focusing aspherical mirrors and a lens of three lenses, works with a narrow field of view. To ensure operation with a variable field of view, this channel contains a lens with a discretely variable focal length, in which, due to the input-output of a group of four lenses, the field of view (medium and wide) is changed. On an average field of view, the lens contains nine lenses, two of which are aspherical; in a wide field of view, the lens contains thirteen lenses, five of which are aspherical. To switch the operating mode from a narrow field of view to medium and wide near the first spectrodivider, a flat mirror is introduced and displayed.

The disadvantages of this device include the following: the first spectrometer in the form of an inclined plate is located in a converging beam of rays and introduces aberrations that are difficult to correct; the infrared channel (3 ... 5 microns) contains a large number of lenses - the total number of lenses is sixteen, five of them with aspherical surfaces.

Also known is an optical system for imaging in the visible and infrared regions of the spectrum (see patent CN 102175318 A, published 09.07. 2011), containing a common input channel consisting of a concave mirror with a central hole and a concave-convex lens with a dichroic coating, reflecting radiation of the spectral range of 0.45 ... 1 μm and transmitting radiation of the spectral range of 3 ... 5 μm (8 ... 12 μm), as well as the first channel, consisting of three lenses and operating in the spectral range of 0.4 ... 1 μm, and the second channel, five lens and working in the spectral range of 3 ... 5 microns (8 ... 12 microns). To ensure the compactness of the system, flat mirrors are used that change the direction of the optical axis.

The disadvantage of this system is the ability to work in each channel with only one field of view.

The closest in technical essence to the claimed optical system, selected as a prototype, is a two-spectral optical system (see patent CN 103293681 A, publ. 09.11. 2013), designed to work in infrared (3 ... 5 μm) and visible (0, 4 ... 0.7 microns) spectral ranges. The system consists of a common channel containing the main concave aspherical mirror located along the rays with a central hole and a secondary convex aspherical mirror, a spectrometer in the form of a prism-cube with a dichroic coating, reflecting the radiation of the visible range of the spectrum and transmitting the radiation of the infrared range of the spectrum, as well as thermal and television channels. The thermal imaging channel (spectral range 3 ... 5 μm) contains a six-lens lens, located in such a way that its front focal plane coincides with the rear focal plane of the input lens, and a radiation receiver with a cooled diaphragm; Four lenses are aspherical. The television channel (spectral range 0.4 ... 0.7 μm) contains a seven-lens lens, located similarly to the lens of the thermal imaging channel, and a radiation receiver. The spectrum splitter is located in a diverging beam of rays between the front focal plane and the first lens of the lens of each channel. Characteristics of the thermal imaging channel: focal length f '= 1500 mm; f-number 3; angular field of view 0.46 °; linear field of view 12 mm. Characteristics of the television channel: focal length f '= 1500 mm; f-number 3; angular field of view 0.23 °; linear field of view 6 mm.

The disadvantage of the described two-spectral system is the ability to work in each channel with only one (narrow) field of view.

The problem to which the invention is directed is to increase the information content of a two-spectral optical system by additionally obtaining information about the observed scene in a continuously changing angular field of view.

The problem is solved due to the fact that in a two-spectral optical system containing the main concave aspherical mirror with a central hole located along the rays, a secondary convex aspherical mirror, a spectro-splitter, a thermal imaging channel with a first lens and a photodetector, and a first television channel with a lens and a photodetector while the outputs of the photodetectors of the thermal imaging and the first television channels are connected to the inputs of the control and information processing device In addition, a second television channel with a lens made to smoothly change the focal length and located in a parallel beam of rays from an infinitely distant object, and a photodetector, the output of which is connected to the corresponding input of the control and information processing device, is introduced into the thermal imaging channel; a photodetector, a second lens and a third lens, configured to smoothly change the focal length and located in parallel beam of rays from an infinitely distant object, while the front focal plane of the second lens coincides with the rear focal planes of the first and third lenses, as well as a device for switching radiation fluxes coupled to the first, second and third lenses and connected to the control output of the information management and processing device .

And also because the main concave and secondary convex aspherical mirrors form an afocal nozzle.

And also the fact that the spectrometer is made in the form of a plane-parallel plate mounted at an angle to the optical axis and is located in a parallel beam of rays after the secondary mirror of the afocal nozzle.

And also the fact that the first lens of the thermal imaging channel is made in the form of sequentially installed positive convex-concave, biconcave and plane-convex lenses.

And also the fact that the second lens of the thermal imaging channel is made in the form of a positive convex-concave lens.

And also the fact that the third lens of the thermal imaging channel is made in the form of sequentially mounted fixed positive convex-concave lenses, movable negative convex-concave and biconcave lenses, mounted with the ability to move along the optical axis, two fixed convex-concave lenses, of which the first is made positive and the second is negative.

And also by the fact that the lens of the first television channel is made in the form of two biconvex, biconcave, negative concave-convex, flat-convex and biconcave lenses installed in series.

And also the fact that the lens of the second television channel is made in the form of sequentially installed first fixed group containing negative convex-concave and concave-convex lenses, gluing from a negative convex-concave and biconvex lens and a biconvex lens, of the second movable group containing a negative convex a concave lens, gluing from a positive concave-convex and biconcave lenses and a positive convex-concave lens, and a third movable group comprising gluing from a biconcave and biconcave convex lenses mounted with the ability to move along the optical axis, the fourth fixed group containing a biconvex lens, gluing a biconvex and negative concave-convex lenses, gluing a biconvex and biconcave lenses, a biconvex lens and two negative lenses, of which the first is convex and the second is concave-convex.

In FIG. 1 shows an optical scheme of a two-spectral optical system.

In FIG. 2 is an optical diagram of a second television channel.

The two-spectral optical system consists of along the rays of the main concave aspherical mirror 1 with a central hole, a secondary convex aspherical mirror 2, a spectro-splitter 3, a thermal imaging channel containing a first lens 4 forming an intermediate image, a second lens 5, and a third lens 6, configured to smooth focal length changes and located in a parallel beam of rays from an infinitely distant object, while the front focal plane of the second object and 5 coincides with the rear focal planes of the first 4 and third 6 lenses, a photodetector 7, a device for switching radiation fluxes, paired with the first 4, second 5 and third 6 lenses and made in the form of a movable flat mirror 8, the first television channel containing a focusing lens 9 and a photodetector 10, of a second television channel comprising a lens 11 configured to smoothly change the focal length and located in a parallel beam of rays from infinitely distant of the object, and a photodetector 12, a control and information processing device 13, the information inputs of which are connected to the photodetectors 7, 10 and 12 of the thermal, first and second television channels, respectively, and the control output is connected to a device for switching radiation fluxes 8. The main one is concave 1 and a secondary convex 2 aspherical mirrors form an afocal nozzle; the spectrometer 3 is made in the form of a plane-parallel plate mounted at an angle to the optical axis and is located in a parallel beam of rays after the secondary mirror 2. The first lens of the thermal imaging channel 4 contains successively mounted positive convex-concave lens 4.1, a biconcave lens 4.2, and a plano-convex lens 4.3. The second lens of the thermal imaging channel 5 is made in the form of a single positive convex-concave lens. The third lens of the thermal imaging channel 6 contains successively mounted fixed positive convex-concave lens 6.1, movable negative convex-concave 6.2 and biconcave 6.3 lenses mounted for movement along the optical axis, fixed positive convex-concave lens 6.4 and negative convex-concave lens 6.5. The lens 9 of the first television channel contains sequentially mounted biconvex lenses 9.1 and 9.2, a biconcave lens 9.3, a negative concave-convex lens 9.4, a plano-convex lens 9.5 and a biconcave lens 9.6. The lens 11 of the second television channel consists of a series-mounted first fixed group A containing negative convex-concave 11.1 and concave-convex 11.2 lenses, gluing from a negative convex-concave 11.3 and a biconvex 11.4 lens and a biconvex lens 11.5, a second movable group B containing a negative convex-concave lens 11.6, gluing from positive concave-convex 11.7 and biconcave 11.8 lenses, positive convex-concave lens 11.9, and a third movable group B containing gluing from biconcave 11.10 and biconvex 11.11 lenses mounted with the possibility of moving along the optical axis of the fourth fixed group Г containing a biconvex lens 11.12, gluing a biconvex 11.13 and a concave-convex 11.14 lenses, gluing a biconvex 11.15 and a biconcave 11.16, double-lens, double convex-concave 11.18 and concave-convex 11.19 lenses. In addition, an information display device 14, the input of which is connected to the output of the information management and processing device 13, and flat mirrors 15, 16, 17, 18, which provide a compact design, are additionally shown.

Technical characteristics of a two-spectral optical system are presented in table 1.

Table 2 shows the design parameters of a specific example of a thermal imaging channel of a two-spectral optical system.

Table 3 shows the design parameters of a specific example of the execution of the first and second television channels of a two-spectral optical system.

Tables 4 and 5 show some values of the variable air gaps Dl, D2, D3 of the lens 6 of the thermal imaging channel and D4, D5, D6 of the lens 11 of the second television channel.

Two-spectrum optical system operates as follows.

To detect the object of observation in the thermal imaging channel and in the second television channel, a continuously changing field of view is selected with the arrangement of optical elements providing a wide angular field of view, which corresponds to the minimum value of the focal length. In the thermal imaging channel, radiation from an infinitely distant object hits the first lens 6.1 of lens 6. After passing through lenses 6.1-6.5 of lens 6, the rays form an intermediate image in the focal plane F '(6), then they are reflected by a flat mirror 8 of the radiation flux switching device installed in the position 8 (6), pass the second lens 5 and form an image in the plane of the sensitive elements of the photodetector 7. In the second television channel, radiation from an infinitely distant object enters the first lens 11 .1 of the lens 11. After passing through the lenses 11.1-11.19 of the lens 11, the rays form an image in the plane of the sensitive elements of the photodetector 12. The signals from the photodetector 7 and 12 are fed to the control and information processing device 13 with the subsequent display of the information display device 14.

To increase the information content of the observation, depending on the distance to the object, its size and location, speed, simultaneous movement of the lenses 6.2 and 6.3 of the third lens 6 of the thermal imaging channel and lens groups B and C of the lens 11 of the second television channel, in accordance with the tables 4 and 5 values of variable air gaps, a smooth change in the focal length of the lenses 6 and 11 is carried out, while the object of observation is constantly in the field of view of the system. After the third possible lens focal length 6 and the lens 11 of the second television channel reaches the maximum possible focal length, the system is switched to a narrow field of view, which provides a more detailed examination of the observation object.

In the narrow field of view mode, radiation from an infinitely distant object is reflected sequentially from the main concave aspherical mirror 1 and the secondary convex aspherical mirror 2 and hits the spectrometer 3. The infrared radiation (thermal imaging channel) passes through the spectrometer 3, the visible radiation (the first television channel) reflected from him. In the thermal imaging channel, the rays refracted by the spectrometer 3 are reflected by the mirror 15, the lenses 4.1-4.3 of the lens 4 pass, reflected by the mirror 16 and form an intermediate image in the focal plane F '(4), then reflected by the flat mirror 8 of the radiation flux switching device installed in position 8 ( 4), pass the second lens 5 and fall into the photodetector 7, in the plane of the sensitive elements of which an image is formed. In the first television channel, the rays reflected by the spectrum splitter 3 and mirror 17 pass through the lenses 9.1-9.5 of the lens 9, are reflected by the mirror 18, pass through the lens 9.6 of the lens 9 and form an image in the plane of the sensitive elements of the photodetector 10. The signals from the photodetector devices 7 and 10 are fed to the control device and processing information 13 with subsequent display on the screen of the display device information 14.

In the thermal imaging channel, the switching of operating modes from a continuously changing field of view to a narrow field of view is carried out using the switching device 8 according to the signals of the control and information processing device 13.

In the television channel, the signals from the photodetector devices 10 and 12 enter the control and information processing device 13. The radiation in the first and second television channels in the modes of narrow and continuously changing fields of view is received in parallel (simultaneously), and switching from one operating mode to another is carried out in the control device and information processing 13 due to the output to the screen of the display device information 14 signals from only one of the photodetector devices.

Thus, the implementation of a two-spectral optical system in accordance with the formula of the claimed materials increases its information content by entering an operating mode in each spectral range that allows obtaining additional information about the object of observation in a continuously changing angular field of view, which ensures higher efficiency of search, detection and recognition objects.

Claims (8)

1. A two-spectral optical system comprising a main concave aspherical mirror with a central hole located along the rays, a secondary convex aspherical mirror, a spectro-splitter, a thermal imaging channel with a first lens and a photodetector, and a first television channel with a lens and a photodetector, while the outputs of the photodetector are thermal imaging and the first television channels are connected to the inputs of the control and information processing device, characterized in that the second television a channel with a lens made to smoothly change the focal length and located in a parallel beam of rays from an infinitely distant object, and a photodetector, the output of which is connected to the corresponding input of the control and information processing device, a second lens paired with a photodetector is additionally introduced and a third lens configured to smoothly change the focal length and located in a parallel beam of rays from at the same time, the front focal plane of the second lens coincides with the rear focal planes of the first and third lenses, as well as a radiation flux switching device coupled to the first, second and third lenses and connected to the control output of the information control and processing device. 2. The system according to claim 1, characterized in that the main concave and secondary convex aspherical mirrors form an afocal nozzle. 3. The system according to claim 1, characterized in that the spectrometer is made in the form of a plane-parallel plate mounted at an angle to the optical axis and is located in a parallel beam of rays after the secondary mirror of the afocal nozzle. 4. The system according to p. 1, characterized in that the first lens of the thermal imaging channel is made in the form of sequentially installed positive convex-concave, biconcave and plane-convex lenses. 5. The system according to claim 1, characterized in that the second lens of the thermal imaging channel is made in the form of a positive convex-concave lens. 6. The system according to p. 1, characterized in that the third lens of the thermal imaging channel is made in the form of successively mounted motionless positive convex-concave lenses, movable negative convex-concave and biconcave lenses mounted with the possibility of moving along the optical axis, two stationary convex-concave lenses, of which the first is positive and the second is negative. 7. The system according to p. 1, characterized in that the lens of the first television channel is made in the form of two biconvex, biconcave, negative concave-convex, flat-convex and biconcave lenses installed in series. 8. The system according to p. 1, characterized in that the lens of the second television channel is made in the form of sequentially installed first fixed group containing negative convex-concave and concave-convex lenses, gluing from a negative convex-concave and biconvex lens and a biconvex lens, the second a movable group containing a negative convex-concave lens, gluing a positive concave-convex and biconcave lens and a positive convex-concave lens, and a third movable group containing a gluing of two ovaconvex and biconvex lenses mounted with the ability to move along the optical axis, the fourth fixed group containing a biconvex lens, gluing a biconvex and negative concave-convex lenses, gluing a biconvex and biconcave lenses, the first biconvex lens, and two negative ones convex-concave, and the second concave-convex.

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