Compact short-wave dual-band optical lens

Abstract

The invention discloses a compact short-wave dual-band optical lens, and belongs to the technical field of optical machinery. Comprising two sets of optical systems, wherein the 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 doublet lens, a triplet lens and a first wave band optical filter along an optical path; the 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 doublet lens, a triplet lens and a second wave band optical filter along the optical path; and the surfaces of the first wave band optical filter and the second wave band optical filter are respectively plated with different film systems which are used for transmitting short wave infrared light of different wave bands. The problems that a multi-band optical alarm lens is multiple in design, large in size, complex in structure and tedious in installation and adjustment process are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of optical machinery, and in particular relates to a compact short-wave dual-band optical lens. Background Art

[0002] For airborne optoelectronic warning equipment, in order to improve product performance, it is necessary to detect infrared radiation in different bands in the surrounding airspace. Dual-band shortwave detection can greatly increase the detection range, improve warning capabilities and reduce false warnings. However, due to the weight and volume limitations of airborne products, compact and simplified lens structure design is a trend. The integrated and compact design of dual-band lenses can not only reduce product size and weight, but also reduce assembly errors during lens assembly, improve optical accuracy, and thus improve performance.

[0003] At present, the lens design of multi-band optical warning is mostly large in size, complex in configuration and cumbersome in assembly and adjustment process. Therefore, through reasonable structural design, it is possible to improve the optical performance of dual-band imaging, reduce the size of the lens, achieve lightweight design, and improve assembly efficiency, which is of great significance to the optomechanical design in the field of optoelectronic warning. Summary of the invention

[0004] Technical issues to be solved:

[0005] In order to avoid the shortcomings of the prior art, the present invention provides a compact short-wave dual-band optical lens, which integrates two optical lenses into one, and images short-wave infrared of different bands by setting different filters, which not only meets the optical performance requirements but also realizes compact and simplified design. The present invention is applied to airborne optoelectronic warning products, solving the problems of large size, complex configuration and cumbersome assembly and adjustment process of multi-band optical warning lens design.

[0006] The technical solution of the present invention is: a compact short-wave dual-band optical lens, comprising two sets of optical systems, wherein the first optical system is provided with a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a doublet, a triplet, and a first-band filter in sequence along the optical path; the second optical system is provided with a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a doublet, a triplet, and a second-band filter in sequence along the optical path; the surfaces of the first-band filter and the second-band filter are respectively coated with different film systems for transmitting 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 in the lens barrel through a lens spacer, the lens spacers installed between the first lens and the second lens and between the second lens and the third lens are made of 2Cr13 steel, and the remaining lens spacers are all 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, the fifth lens, the sixth lens, the seventh lens, the doublet lens, and the triplet lens are located at the small diameter end of the lens barrel, wherein the fourth lens is installed on the stepped surface through a lens spacer, and a gasket is arranged on the stepped surface to fine-tune the lens gap.

[0011] A further technical solution of the present invention is that the double-glued lens and the triple-glued lens are integrated by a gluing process, the lens spacer used for positioning is in extrusion contact with the lens with the largest diameter, and 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 axially 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.

[0013] A further technical solution of the present invention is that the two lens barrels are symmetrically structured and fixed on a lens barrel fixing frame.

[0014] A further technical solution of the present invention is that the lens barrel fixing frame is an L-shaped frame structure, the frame in the vertical direction is provided with a lens barrel mounting hole, and the frame in the horizontal direction serves as a fixed support surface.

[0015] An airborne optoelectronic warning product includes a compact short-wave dual-band optical lens and an infrared detector. 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 under the action of two filters and enters two different infrared detectors respectively to complete short-wave infrared imaging 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, and the height after installation is adjusted by adding or removing gaskets.

[0017] Beneficial Effects

[0018] The beneficial effects of the present invention are as follows: the present invention provides a compact short-wave dual-band optical lens structure, and the overall structure has the advantages of being simple and compact, easy to install, and capable of realizing short-wave dual-band infrared imaging. Compared with a single-band single lens, the main advantage is that: the target radiation peak band is selected as the main band, and then a band is selected as the reference band. The target radiation accounts for a relatively high proportion in the main band, while the clutter interference such as sunlight and background accounts for a relatively low proportion in the main band. The above-mentioned characteristic values ​​can be used to distinguish between the target and the clutter interference, thereby improving the detection efficiency. Compared with a two-color optical system using a color separation filter wheel, the present invention can avoid the use of a color separation filter component, avoid the use of a motor and its control system, reduce the system volume, and at the same time improve the assembly efficiency, which has great benefits. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0021] Figure 3 It is a schematic diagram of the lens spacers, gaskets and other structural parts inside the lens barrel.

[0022] Explanation of the reference numerals in the accompanying drawings: 1. short-wave lens barrel, 2. band I detector bracket, 3. band II detector bracket, 4. screws, 5-11. lenses, 12. double-cemented mirror, 13. triple-cemented mirror, 14. band I filter, 15. band II filter, 16-23, lens spacer, 24. gasket. DETAILED DESCRIPTION

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

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0025] In view of the problems that the existing multi-band optical alarm lens design is large in size, complex in configuration and cumbersome in assembly and adjustment process, the present invention provides a compact short-wave dual-band optical lens, comprising two sets of optical systems, wherein the first optical system sequentially arranges a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a doublet, a triplet and a first band filter along the optical path; the second optical system sequentially arranges a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a doublet, a triplet and a second band filter along the optical path; the surfaces of the first band filter and the second band filter are respectively coated with different film systems for transmitting 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 in two axially parallel lens barrels, and the two lens barrels are symmetrically structured and fixed on a lens barrel fixing frame. The lens barrel fixing frame is an L-shaped frame structure, with a lens barrel mounting hole on the vertical frame and a horizontal frame as a fixed support surface.

[0030] The invention discloses an airborne photoelectric warning product, comprising a compact short-wave dual-band optical lens and an infrared detector. After the infrared radiation passes through two optical systems of the compact short-wave dual-band optical lens respectively, the short-wave infrared radiation of different bands is separated under the action of two filters and enters two different infrared detectors respectively, thereby completing short-wave infrared imaging of different bands.

[0031] The optical lens adopts a one-shot imaging optical configuration, has a relatively compact structure, and has a loose tolerance. It adopts an f-θ equidistant projection method, and introduces negative distortion to make the angular resolution of each pixel of the system consistent.

[0032] The above technical solution is further described below in conjunction with the accompanying drawings:

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

[0034] Reference Figure 2The figure shows a schematic diagram of the optical lenses inside the lens barrel of this embodiment. The first lens barrel contains the first band optical system, and along the optical path, there are the first lens 5, the second lens 6, the third lens 7, the fourth lens 8, the fifth lens 9, the sixth lens 10, the seventh lens 11, the doublet 12, the triplet 13, and the first band filter 14; the second lens barrel contains the second band optical system, and along the optical path, there are the first lens 5, the second lens 6, the third lens 7, the fourth lens 8, the fifth lens 9, the sixth lens 10, the seventh lens 11, the doublet 12, the triplet 13, and the 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 respectively, allowing short-wave infrared light of different bands to pass through. Except for the different surface coatings, the dimensions, materials and tolerance requirements of the two are exactly the same.

[0036] Reference Figure 3 The figure shows a schematic diagram of the lens spacers, gaskets and other structural parts inside the lens barrel of this embodiment; the first lens 5, the second lens 6, the third lens 7, the fourth lens 8, the fifth lens 9, the sixth lens 10, the seventh lens 11, the doublet 12, the triplet 13, and the band filter 14 / 15 are positioned in the lens barrel through the lens spacers 16-23 and the gasket 24.

[0037] Specifically, the lens spacers 16 and 17 are made of 2Cr13 steel, and the thickness is processed according to the negative difference. When the lens is installed, it is ground to a suitable thickness. The remaining lens spacers 18 to 23 are made of aluminum alloy, and their accuracy is ensured by machining. The gasket 24 can fine-tune the lens gap to achieve the best imaging effect.

[0038] Specifically, the lenses 5 to 11, the double-cemented lens 12, the triple-cemented lens 13, and the lens spacers 16 to 23 inside the two lens barrels of the lens barrel 1 are completely identical and can be replaced with each other. The double-cemented lens 12 and the triple-cemented lens 13 are processed into one piece by a gluing process, and the lens spacers 22 and 23 are only pressed and contacted with the lens with the largest diameter, and other lenses are not subjected to force.

[0039] The band I detector bracket 2 and the band II detector bracket 3 are directly mounted on the lens barrel 1 by means of screws 4, and the height is processed according to the negative difference, and the height is adjusted by adjusting the gasket.

[0040] The installation requirements of a compact short-wave dual-band optical lens of this embodiment are as follows:

[0041] When installing the lens, the lenses 5 to 11 and the lens spacers 16 to 23 are inserted into the lens barrel in order, and then optical debugging is performed. The lens spacers 16 and 17 are made of 2Cr13 steel with a thickness tolerance of +0.2 to +0.3. When installing the lens, the imaging is adjusted to the best state by grinding the lens spacers 16 and 17 and adjusting the gaskets, and then the sealing is performed. Subsequently, the band I filter 14 and the band II filter 15 are glued and fixed. Finally, the band I detector bracket 2 and the band II detector bracket 3 are installed on the lens structure. The height tolerance of the two brackets is -0.1 to 0, and the height after installation can be adjusted by adding gaskets.

[0042] The lens barrel 1 is composed of a completely symmetrical double lens barrel. The parameters of the single lenses of band I and band II are consistent, and they are respectively packaged with the detector to ensure good focal plane coplanarity; the two lens barrels can realize short-wave infrared imaging of different bands, and the surfaces of the band I filter 14 and the band II filter 15 are respectively coated with different film systems to allow short-wave infrared light of different bands to pass through, which are band I: 0.9μm~1.1μm, band II: 1.5μm~1.7μm. When the infrared radiation passes through the two optical systems respectively, under the action of the two filters, the short-wave infrared radiation of different bands will be separated and enter different infrared detectors respectively, 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 the optical performance, reduce the size of the lens, realize lightweight design, and has the advantages of being simple, compact, and easy to install.

[0044] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A compact short-wave dual-band optical lens, characterized in that: The invention comprises two optical systems. The first optical system is provided with a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a doublet mirror, a triplet mirror and a first band filter in sequence along the optical path. The second optical system is provided with a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a doublet mirror, a triplet mirror and a second band filter in sequence along the optical path. The surfaces of the first band filter and the second band filter are respectively coated with different film systems so as to transmit short-wave infrared light of different bands.

2. A compact short-wave dual-band optical lens according to claim 1, characterized in that: The optical parameters of each lens group in the optical system are as follows:

3. A compact short-wave dual-band optical lens according to claim 2, characterized in that: Each lens of the optical system is positioned in the lens barrel through a lens spacer. The lens spacers installed between the first lens and the second lens and between the second lens and the third lens are made of 2Cr13 steel, and the remaining lens spacers are made of aluminum alloy.

4. A compact short-wave dual-band optical lens according to claim 3, characterized in that: 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, the fifth lens, the sixth lens, the seventh lens, the doublet lens, and the triplet lens are located at the small-diameter end of the lens barrel, wherein the fourth lens is mounted on the stepped surface through a lens spacer, and a gasket is arranged on the stepped surface to fine-tune the lens gap.

5. A compact short-wave dual-band optical lens according to claim 4, characterized in that: The double-glued lens and the triple-glued lens are integrated by a gluing process, and the lens spacer used for positioning is in extrusion contact with the lens with the largest diameter, and other lenses are not subjected to force.

6. A compact short-wave dual-band optical lens according to claim 5, characterized in that: The two optical systems are installed in two axially parallel lens barrels; the first optical system is used for infrared imaging in the wavelength range of 0.9 μm to 1.1 μm, and the second optical system is used for infrared imaging in the wavelength range of 1.5 μm to 1.7 μm.

7. A compact short-wave dual-band optical lens according to claim 6, characterized in that: The two lens barrels are symmetrical in structure and are fixed on a lens barrel fixing frame.

8. A compact short-wave dual-band optical lens according to claim 7, characterized in that: The lens barrel fixing frame is an L-shaped frame structure, the frame in the vertical direction is provided with a lens barrel mounting hole, and the frame in the horizontal direction serves as a fixed supporting surface.

9. An airborne optoelectronic warning product, characterized in that: The invention comprises the compact short-wave dual-band optical lens and infrared detector as described in any one of claims 1 to 8. After the infrared radiation passes through the two optical systems of the compact short-wave dual-band optical lens respectively, the short-wave infrared radiation of different bands is separated under the action of two filters and enters two different infrared detectors respectively, thereby completing the short-wave infrared imaging of different bands.

10. The airborne optoelectronic warning product according to claim 9, characterized in that: The two optical systems are provided with detector brackets at the exit ends of the lens barrels respectively. The bottom surfaces of the two detector brackets are installed on the fixed support surface of the lens barrel fixing frame. The height tolerance is -0.1 to 0. The height after installation is adjusted by adding or removing gaskets.

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