A compact shortwave dual-band optical lens

Abstract

The application discloses a compact short-wave dual-waveband optical lens, and belongs to the technical field of optical machinery; the compact short-wave dual-waveband optical lens comprises two sets of optical systems; a first optical system is sequentially provided with a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a double-cemented lens, a three-cemented lens and a first waveband filter along an optical path; a second optical system is sequentially provided with a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a double-cemented lens, a three-cemented lens and a second waveband filter along the optical path; the surfaces of the first waveband filter and the second waveband filter are respectively coated with different film systems, and are used for transmitting different waveband short-wave infrared rays. The problems of large volume, complex configuration and complicated assembly process of the multi-waveband optical warning lens design are solved.

Description

Technical Field

[0001] This invention belongs to the field of optical and mechanical technology, and specifically relates to a compact short-wavelength dual-band optical lens. Background Technology

[0002] For airborne optoelectronic alarm equipment, in order to improve product performance, it is necessary to detect infrared radiation of different bands in the surrounding airspace. Dual-band shortwave detection can significantly increase the detection range, improve alarm capability, and reduce false alarms. However, due to the weight and size limitations of airborne products, compact and simplified lens structure design is a trend. Through the integrated compact design of dual-band lenses, the product size and weight can be reduced, while the assembly error in the lens assembly process can be reduced, optical accuracy can be improved, and thus performance can be improved.

[0003] Currently, the lens designs for multi-band optical alarms are often large, complex in configuration, and involve cumbersome assembly and adjustment processes. Therefore, through reasonable structural design, it is possible to improve the optical performance of dual-band imaging, reduce the lens size, achieve lightweight design, and improve assembly efficiency, which is of great significance to the optomechanical design in the field of optoelectronic alarms. Summary of the Invention

[0004] The technical problem to be solved:

[0005] To overcome the shortcomings of existing technologies, this invention provides a compact short-wave dual-band optical lens that integrates two optical lenses into one unit. By setting different filters, it images different short-wave infrared bands, satisfying optical performance requirements while achieving a compact and simplified design. This invention is applied to airborne optoelectronic alarm products, solving the problems of large size, complex configuration, and cumbersome assembly and adjustment processes in multi-band optical alarm lens designs.

[0006] The technical solution of this invention is: a compact short-wave dual-band optical lens, comprising two optical systems. The first optical system is arranged along the optical path as follows: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a cemented doublet lens, a cemented triplet lens, and a first-band filter. The second optical system is arranged along the optical path as follows: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a cemented doublet lens, a cemented triplet lens, and a second-band filter. The surfaces of the first-band filter and the second-band filter are respectively coated with different film systems to transmit short-wave infrared light of different bands.

[0007] A further technical solution of the present invention is that the optical parameters of each lens group in the optical system are as follows:

[0008]

[0009] A further technical solution of the present invention is: each lens of the optical system is positioned inside the lens barrel by lens spacers, the lens spacers installed between the first lens and the second lens, and between the second lens and the third lens are made of steel 2Cr13, and the remaining lens spacers are made of aluminum alloy.

[0010] A further technical solution of the present invention is: the inner hole of the lens barrel is a stepped hole, the first lens, the second lens, the third lens, and the fourth lens are located at the large diameter end of the lens barrel, and the fifth lens, the sixth lens, the seventh lens, the cemented doublet lens, and the cemented triplet lens are located at the small diameter end of the lens barrel. The fourth lens is mounted on the stepped surface by a lens spacer, and a shim is provided on the stepped surface to finely adjust the lens gap.

[0011] A further technical solution of the present invention is: the double-cemented lens and the triple-cemented lens are both processed into one piece by adhesive bonding process, and the lens spacer used for positioning is pressed and contacted with the lens with the largest diameter, while the other lenses are not subjected to force.

[0012] A further technical solution of the present invention is: the two optical systems are installed in two mirror tubes arranged in parallel axes; the first optical system is used for infrared imaging in the band of 0.9μm to 1.1μm, and the second optical system is used for infrared imaging in the band of 1.5μm to 1.7μm.

[0013] A further technical solution of the present invention is: the two lens tubes are symmetrically arranged and fixed on the lens tube fixing frame.

[0014] A further technical solution of the present invention is: the lens barrel fixing frame is an L-shaped frame structure, with lens barrel mounting holes provided on the vertical frame and the horizontal frame serving as a fixing support surface.

[0015] An airborne optoelectronic alarm product includes a compact short-wave dual-band optical lens and an infrared detector. Infrared radiation passes through two optical systems of the compact short-wave dual-band optical lens, and under the action of two filters, the short-wave infrared radiation of different bands is separated and enters two different infrared detectors to complete the imaging of short-wave infrared radiation of different bands.

[0016] A further technical solution of the present invention is: detector brackets are respectively installed at the exit ends of the lens barrels of the two optical systems, and the bottom surfaces of the two detector brackets are installed on the fixed support surface of the lens barrel fixing frame, with a height tolerance of -0.1 to 0. The height after installation is adjusted by adding or removing shims.

[0017] Beneficial effects

[0018] The beneficial effects of this invention are as follows: This invention provides a compact short-wavelength dual-band optical lens structure, which has the advantages of simple and compact overall structure, convenient installation, and the ability to achieve short-wavelength dual-band infrared imaging. Compared with a single-band single-lens design, its main advantage lies in selecting the target radiation peak band as the main band and then selecting another band as the reference band. Target radiation accounts for a high proportion in the main band, while sunlight, background, and other clutter interference account for a low proportion. These characteristic values ​​can be used to distinguish the target from clutter interference, improving detection efficiency. Compared with a dual-color optical system using a dichroic filter wheel, this invention avoids the use of dichroic filter components, motors, and their control systems, reducing system size and improving assembly efficiency, thus offering significant benefits. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of a compact shortwave dual-band optical lens provided by the present invention;

[0020] Figure 2 This is a schematic diagram of the optical lenses inside the lens barrel;

[0021] Figure 3 This is a schematic diagram of the internal structural components of the lens barrel, such as lens spacers and gaskets.

[0022] Explanation of reference numerals in the attached drawings: 1. Shortwave mirror tube; 2. Band I detector bracket; 3. Band II detector bracket; 4. Screw; 5-11. Lens; 12. Cemented doublet lens; 13. Cemented triplet lens; 14. Band I filter; 15. Band II filter; 16-23. Lens spacer; 24. Gasket. Detailed Implementation

[0023] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0024] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0025] Addressing the issues of existing multi-band optical alarm lens designs being large, complex in configuration, and cumbersome in assembly and adjustment, this invention provides a compact short-wave dual-band optical lens, comprising two optical systems. The first optical system, along the optical path, sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a cemented doublet lens, a cemented triplet lens, and a first-band filter. The first and second band filters are coated with different film systems to transmit short-wave infrared light of different bands.

[0026] The optical parameters of each lens group in the optical system are as follows:

[0027]

[0028]

[0029] Specifically, the two optical systems are installed inside two axially parallel lens barrels; and the two lens barrels are symmetrically arranged and fixed to a lens barrel mounting bracket. The lens barrel mounting bracket is an L-shaped frame structure, with lens barrel mounting holes on the vertical frame and the horizontal frame serving as a fixed support surface.

[0030] The present invention discloses an airborne optoelectronic alarm product, comprising a compact short-wave dual-band optical lens and an infrared detector. Infrared radiation passes through two optical systems of the compact short-wave dual-band optical lens, and under the action of two filters, short-wave infrared radiation of different bands is separated and enters two different infrared detectors to complete short-wave infrared imaging of different bands.

[0031] The optical lens adopts a single-image optical configuration, which is relatively compact and has loose tolerances. It also uses an f-θ equidistant projection method, which introduces negative distortion to make the angular resolution of each pixel in the system consistent.

[0032] The above technical solution will be further explained below with reference to the accompanying drawings:

[0033] Reference Figure 1 The diagram shown is an overall schematic of a compact shortwave dual-band optical lens according to this embodiment, including a shortwave lens barrel 1, a band I detector bracket 2, and a band II detector bracket 3. The shortwave lens barrel 1 is composed of two completely symmetrical lens barrels in an integrated design. The two lens barrels can realize shortwave infrared imaging in different bands, namely band I: 0.9μm~1.1μm and band II: 1.5μm~1.7μm.

[0034] Reference Figure 2The diagram shows the internal optical lenses of the lens barrel in this embodiment. The first lens barrel contains a first-band optical system, which consists of, along the optical path, a first lens 5, a second lens 6, a third lens 7, a fourth lens 8, a fifth lens 9, a sixth lens 10, a seventh lens 11, a cemented doublet lens 12, a cemented triplet lens 13, and a first-band filter 14. The second lens barrel contains a second-band optical system, which consists of, along the optical path, a first lens 5, a second lens 6, a third lens 7, a fourth lens 8, a fifth lens 9, a sixth lens 10, a seventh lens 11, a cemented doublet lens 12, a cemented triplet lens 13, and a second-band filter 14.

[0035] Specifically, the surfaces of the first band filter 14 and the second band filter 14 are coated with different film systems to allow short-wave infrared light of different bands to pass through. Apart from the different surface coatings, the two have the same size, material and tolerance requirements.

[0036] Reference Figure 3 The diagram shows the internal structure of the lens barrel in this embodiment, including lens spacers, gaskets, etc. The first lens 5, second lens 6, third lens 7, fourth lens 8, fifth lens 9, sixth lens 10, seventh lens 11, cemented doublet lens 12, cemented triplet lens 13, and band filters 14 / 15 are positioned inside the lens barrel by lens spacers 16-23 and gaskets 24.

[0037] Specifically, the lens spacers 16 and 17 are made of 2Cr13 steel, machined to a negative tolerance thickness. During lens installation, they are ground to the appropriate thickness. The remaining lens spacers 18-23 are made of aluminum alloy, and their precision is ensured through machining. The shim 24 allows for fine-tuning of the lens gap to achieve optimal imaging.

[0038] Specifically, the lenses 5-11, cemented doublet lens 12, cemented triplet lens 13, and lens spacers 16-23 inside the two lens barrels of the lens barrel 1 are identical and can be interchanged in equivalence. The cemented doublet lens 12 and the cemented triplet lens 13 are bonded together by an adhesive process, and the lens spacers 22 and 23 only come into contact with the lens with the largest diameter, while the other lenses are not subjected to force.

[0039] The band I detector bracket 2 and band II detector bracket 3 are directly mounted on the lens barrel 1 by screws 4. The height is machined according to the negative tolerance and the height is adjusted by adjusting shims.

[0040] This embodiment describes the installation requirements for a compact short-wave dual-band optical lens:

[0041] During lens installation, lenses 5-11 and lens spacers 16-23 are sequentially inserted into the lens barrel, followed by optical adjustment. Lens spacers 16 and 17 are made of 2Cr13 steel with a thickness tolerance of +0.2 to +0.3. During lens installation, the imaging is adjusted to the optimal state by grinding lens spacers 16 and 17 and adjusting with shims. After sealing with glue, band I filter 14 and band II filter 15 are glued in place. Finally, band I detector bracket 2 and band II detector bracket 3 are installed on the lens structure. The height tolerance of the two brackets is -0.1 to 0. The height after installation can be adjusted by adding shims.

[0042] The lens tube 1 consists of two completely symmetrical lens tubes. The single lens parameters of band I and band II are consistent and are respectively encapsulated with the detector to ensure good focal plane coplanarity. The two lens tubes can realize short-wave infrared imaging of different bands. The surfaces of the band I filter 14 and the band II filter 15 are coated with different film systems to allow short-wave infrared light of different bands to pass through. The band I is 0.9μm to 1.1μm and the band II is 1.5μm to 1.7μm. When the infrared radiation passes through the two optical systems, the short-wave infrared radiation of different bands will be separated by the action of the two filters and enter different infrared detectors, thereby realizing short-wave infrared imaging of different bands.

[0043] In summary, the compact short-wave dual-band optical lens structure of the present invention can realize short-wave dual-band infrared imaging, meet optical performance requirements, reduce lens size, achieve lightweight design, and has the advantages of being simple, compact, and easy to install.

[0044] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A compact short-wavelength dual-band optical lens, characterized in that: It includes two optical systems. The first optical system is arranged along the optical path as follows: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a cemented doublet lens, a cemented triplet lens, and a first-band filter. The second optical system is arranged along the optical path as follows: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a cemented doublet lens, a cemented triplet lens, and a second-band filter. The surfaces of the first-band filter and the second-band filter are coated with different film systems to transmit short-wave infrared light of different wavelengths. The optical parameters of each lens group in the optical system are as follows: Each lens of the optical system is positioned inside the lens barrel by lens spacers. The lens spacers installed between the first and second lenses and between the second and third lenses are made of 2Cr13 steel, while the remaining lens spacers are made of aluminum alloy. The inner hole of the lens barrel is a stepped hole. The first lens, the second lens, the third lens, and the fourth lens are located at the large diameter end of the lens barrel, and the fifth lens, the sixth lens, the seventh lens, the cemented doublet lens, and the cemented triplet lens are located at the small diameter end of the lens barrel. The fourth lens is mounted on the stepped surface by a lens spacer, and a shim is set on the stepped surface to finely adjust the lens gap. Both the double-laminated and triple-laminated lenses are bonded together using an adhesive process. The lens spacer used for positioning is pressed against the lens with the largest diameter, while the other lenses are not subjected to force. The two optical systems are installed in two parallel lens barrels; the first optical system is used for infrared imaging in the band of 0.9μm to 1.1μm, and the second optical system is used for infrared imaging in the band of 1.5μm to 1.7μm. The two lens tubes are symmetrically arranged and fixed on the lens tube holder; The lens barrel mounting bracket is an L-shaped frame structure, with lens barrel mounting holes on the vertical frame and the horizontal frame serving as a fixed support surface.

2. An airborne photoelectric alarm product, characterized in that: The system includes the compact short-wave dual-band optical lens and infrared detector as described in claim 1. After the infrared radiation passes through the two optical systems of the compact short-wave dual-band optical lens, the short-wave infrared radiation of different bands is separated by two filters and enters two different infrared detectors to complete the imaging of short-wave infrared radiation of different bands.

3. The airborne photoelectric alarm product according to claim 2, characterized in that: The two optical systems are respectively equipped with detector brackets at the exit ends of the lens barrels. The bottom surfaces of the two detector brackets are mounted on the fixed support surface of the lens barrel fixing frame, with a height tolerance of -0.1 to 0. The height after installation is adjusted by adding or removing shims.

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