Compact long-focal-length common-aperture multi-sensor photoelectric load optical system

Abstract

The utility model discloses a compact long-focal-length common-aperture multi-sensor photoelectric load optical system, which belongs to the technical field of optical engineering and is provided with a medium-wave infrared channel, a short-wave infrared channel and a visible light channel. And the light path is reflected by the fast reflecting mirror, the three channels are subjected to light splitting through the light splitting sheet and the light splitting prism, and the spectrums after light splitting are imaged to the corresponding detectors through respective channel lenses. According to the utility model, through the common optical path design configuration of sharing the main reflector, the secondary reflector and the fast reflector, the optical path is greatly simplified, the transmittance of the optical system is effectively improved, the volume of the optical system is greatly compressed, and the light and small size of the long-focus multi-sensor photoelectric load system is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of optical engineering, in particular to a compact long-focal-length common-aperture multi-sensor photoelectric load optical system. Background Art

[0002] Airborne optoelectronic pods achieve all-weather surveillance and reconnaissance through multi-band hybrid detection, using the different characteristic information of the target imaging in different bands to improve the probability of target detection and reduce the false alarm rate. Long-focal-length and large-aperture optical systems are the key to achieving long-range search and detection. Multi-band optics can increase the effective distance and compress the system volume through common aperture. For this reason, long-focal-length and common-aperture multi-sensor optoelectronic payload optical systems have become important components for the lightweight and miniaturization of airborne optoelectronic pods.

[0003] The common-aperture multi-sensor optoelectronic payload disclosed in the prior art adopts multiple imaging methods in the common optical path design configuration, has a large number of lenses, and has low transmittance of the optical system. It cannot well solve the contradiction between the improvement of optoelectronic payload performance requirements and the tightening of size and weight, and realize the lightweight and miniaturization of the payload. Utility Model Content

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing a compact long-focal-length common-aperture multi-sensor optoelectronic payload optical system.

[0005] A compact long focal length common aperture multi-sensor optoelectronic payload optical system, comprising: a primary reflector, a secondary reflector, a fast reflector, a beam splitter, a beam splitter prism, a medium wave first lens, a medium wave second lens, a medium wave first folding mirror, a medium wave third lens, a medium wave fourth lens, a medium wave second folding mirror, a medium wave fifth lens, a medium wave detector, a short wave first folding mirror, a short wave first lens, a short wave second lens, a short wave third lens, a short wave fourth lens, a short wave detector, a visible light first lens, a visible light second lens, a visible light third lens, a visible light fourth lens and a visible light detector;

[0006] The secondary reflector is arranged on one side of the main reflector, and the remaining components are arranged on the side opposite to the reflector; on this side, the medium wave detector, the medium wave fifth lens and the medium wave second folding mirror are arranged in sequence from bottom to top, the medium wave fourth lens, the medium wave third lens and the medium wave first folding mirror are arranged in sequence on one side of the medium wave second folding mirror, the medium wave second lens, the medium wave first lens, the beam splitter and the fast reflection mirror are arranged in sequence below the medium wave first folding mirror, the beam splitter and the short wave first folding mirror are arranged in sequence on the side of the beam splitter away from the medium wave detector, the visible light first lens, the visible light second lens, the visible light third lens, the visible light fourth lens and the visible light detector are arranged in sequence below the beam splitter prism, and the short wave first lens, the short wave second lens, the short wave third lens, the short wave fourth lens and the short wave detector are arranged in sequence below the short wave first folding mirror.

[0007] Furthermore, the fast reflection mirror, the beam splitter, the first medium wave folding mirror and the second medium wave folding mirror are all arranged at an angle.

[0008] Furthermore, the included angle between the fast reflection mirror and the optical axis is 45°.

[0009] Furthermore, the included angle between the beam splitter and the optical axis is 45°.

[0010] Furthermore, the included angle between the medium wave first folding mirror and the optical axis is 45°.

[0011] Furthermore, the included angle between the medium wave second folding mirror and the optical axis is 45°.

[0012] Further, the surface type combinations of the primary reflector and the secondary reflector include the following:

[0013] The primary reflector is a parabola, and the secondary reflector is a hyperbolic or high-order aspheric surface;

[0014] The primary reflector is a hyperbolic surface, and the secondary reflector is a hyperbolic surface or a high-order aspherical surface;

[0015] The primary reflector is a high-order aspherical surface, and the secondary reflector is a mirror spherical surface.

[0016] Furthermore, two surfaces of the beam splitter are coated with a beam splitting film and an anti-reflection film respectively.

[0017] Furthermore, the medium-wave first folding mirror, the medium-wave second folding mirror and the short-wave first folding mirror are all coated with a high-reflection film.

[0018] Furthermore, the medium-wave first lens is a biconical lens.

[0019] The technical solution of the utility model has the following advantages:

[0020] 1. The utility model has three channels of medium-wave infrared, near-infrared and visible light. The volume of the optical system is greatly compressed by sharing the front group of folding mirrors and the fast mirror. The light passes through the front group of folding mirrors, the fast mirror, the beam splitter and the beam splitter prism to split the three channels. There is no shared lens in each channel, which effectively improves the optical transmittance.

[0021] 2. The front catadioptric mirror group in the utility model is designed as a long focal length system, the central field of view is perfect for imaging, the image point is far away from the beam splitter and the beam splitter prism, and is located behind them, so the front catadioptric mirror group can be installed and adjusted separately, reducing the difficulty of installation and adjustment;

[0022] 3. The three channels in the utility model share a fast-reflection mirror for image stabilization, which can compensate for the load roll and image shift in the flight direction, and keep the image clear and stable;

[0023] 4. The utility model reduces the space required for the light splitting part by using the combination of the light splitter and the light splitting prism, and the entire optical system space is compact;

[0024] 5. The medium-wave infrared channel of the utility model adopts a secondary imaging structure, and the short-wave infrared channel and the visible light channel both adopt a primary imaging structure, which greatly simplifies the optical path, reduces the number of lenses in each channel, and increases system energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of the optical path of the compact long focal length common aperture multi-sensor optoelectronic payload optical system;

[0027] Figure 2 Design the modulation transfer function (MTF) curve for the MWIR channel;

[0028] Figure 3 Design the modulation transfer function (MTF) curve for the short-wave infrared channel;

[0029] Figure 4 Design the modulation transfer function (MTF) graph for the visible light channel.

[0030] Description of reference numerals:

[0031] 1-primary reflector; 2-secondary reflector; 3-fast reflector;

[0032] 4-beam splitter; 5-beam splitter prism; 6-medium wave first lens;

[0033] 7-medium wave second lens; 8-medium wave first folding mirror; 9-medium wave third lens;

[0034] 10-medium wave fourth lens; 11-medium wave second folding mirror; 12-medium wave fifth lens;

[0035] 13-medium wave detector; 14-short wave first folding mirror; 15-short wave first lens;

[0036] 16-short-wave second lens; 17-short-wave third lens; 18-short-wave fourth lens;

[0037] 19-short wave detector; 20-visible light first lens; 21-visible light second lens;

[0038] 22 - visible light third lens; 23 - visible light fourth lens; 24 - visible light detector. DETAILED DESCRIPTION

[0039] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0040] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] See also Figure 1A compact long focal length common aperture multi-sensor optoelectronic payload optical system, the system includes three channels of medium wave infrared, short wave infrared and visible light, and the system components include: a main reflector 1, a secondary reflector 2, a fast reflector 3, a beam splitter 4, a beam splitter prism 5, a medium wave first lens 6, a medium wave second lens 7, a medium wave first folding mirror 8, a medium wave third lens 9, a medium wave fourth lens 10, a medium wave second folding mirror 11, a medium wave fifth lens 12, a medium wave detector 13, a short wave first folding mirror 14, a short wave first lens 15, a short wave second lens 16, a short wave third lens 17, a short wave fourth lens 18, a short wave detector 19, a visible light first lens 20, a visible light second lens 21, a visible light third lens 22, a visible light fourth lens 23 and a visible light detector 24;

[0044] The secondary reflector 2 is arranged on one side of the main reflector 1, and the remaining components are arranged on the side opposite to the reflector 2; in this side, the medium wave detector 13, the medium wave fifth lens 12 and the medium wave second folding mirror 11 are arranged in sequence from bottom to top, the medium wave fourth lens 10, the medium wave third lens 9 and the medium wave first folding mirror 8 are arranged in sequence on one side of the medium wave second folding mirror 11, the medium wave second lens 7, the medium wave first lens 6, the beam splitter 4 and the fast reflection mirror 3 are arranged in sequence below the medium wave first folding mirror 8, the beam splitter 4 and the short wave first folding mirror 14 are arranged in sequence on the side of the beam splitter 4 away from the medium wave detector 13, the visible light first lens 20, the visible light second lens 21, the visible light third lens 22, the visible light fourth lens 23 and the visible light detector 24 are arranged in sequence below the beam splitter prism 5, and the short wave first lens 15, the short wave second lens 16, the short wave third lens 17, the short wave fourth lens 18 and the short wave detector 19 are arranged in sequence below the short wave first folding mirror 14.

[0045] The light of the target scene is split into three channels through the primary reflector 1, the secondary reflector 2, the fast reflector 3, the beam splitter 4 and the beam splitter prism 5, so that each channel has no shared lens, which is convenient for correcting chromatic aberration and aberration in each band, and effectively improving the transmittance;

[0046] The main reflector 1, the secondary reflector 2, the fast reflector 3, the beam splitter 4, the first medium wave lens 6, the second medium wave lens 7, the first medium wave folding mirror 8, the third medium wave lens 9, the fourth medium wave lens 10, the second medium wave folding mirror 11, the fifth medium wave lens 12 and the medium wave detector 13 form a medium wave infrared channel;

[0047] The primary reflector 1, the secondary reflector 2, the quick reflector 3, the beam splitter 4, the beam splitter prism 5, the short-wave first folding mirror 14, the short-wave first lens 15, the short-wave second lens 16, the short-wave third lens 17, the short-wave fourth lens 18 and the short-wave detector 19 form a short-wave infrared channel;

[0048] The reflector 1, the secondary reflector 2, the fast reflector 3, the beam splitter 4, the beam splitter prism 5, the first visible light lens 20, the second visible light lens 21, the third visible light lens 22, the fourth visible light lens 23 and the visible light detector 24 form a visible light channel;

[0049] The primary reflector 1 and the secondary reflector 2 form a front group of folding and reflecting mirrors, which are used to collect light and compress the beam aperture, and can form images separately; the base material of the primary reflector 1 and the secondary reflector 2 can be microcrystalline glass, silicon carbide and silicon;

[0050] The front group of catadioptric mirrors is designed as a long focal length system, the central field of view is perfect for imaging, the image point is far away from the beam splitter 4 and the beam splitter prism 5, and is located behind them, and can be detected and adjusted separately by an interferometer, reducing the difficulty of adjustment;

[0051] In this embodiment, the quick reflection mirror 3, the beam splitter 4, the first medium wave folding mirror 8 and the second medium wave folding mirror 11 are all arranged tilted.

[0052] The angle between the fast mirror 3 and the optical axis is 45°. The three channels share the fast mirror 3 to compensate for the image shift in the load roll and the flight direction, and keep the image clear and stable.

[0053] The angle between the beam splitter 4 and the optical axis is 45°, which transmits medium-wave infrared and reflects short-wave infrared and visible light, thereby separating the medium-wave infrared channel from the short-wave infrared channel and the visible light channel.

[0054] The angle between the medium wave first folding mirror 8 and the optical axis is 45°.

[0055] The included angle between the medium wave second folding mirror 11 and the optical axis is 45°.

[0056] In this embodiment, the surface combinations of the primary reflector 1 and the secondary reflector 2 include the following:

[0057] The primary reflector 1 is a parabola, and the secondary reflector 2 is a hyperbolic surface or a high-order aspheric surface;

[0058] The primary reflector 1 is a hyperbolic surface, and the secondary reflector 2 is a hyperbolic surface or a high-order aspherical surface;

[0059] The primary reflector 1 is a high-order aspherical surface, and the secondary reflector 2 is a mirror spherical surface.

[0060] In this embodiment, the base material of the beam splitter 4 is selected to be a medium-wave infrared transparent material, and two surfaces of the beam splitter 4 are respectively coated with a beam splitting film and an anti-reflection film.

[0061] In this embodiment, the medium-wave first folding mirror 8, the medium-wave second folding mirror 11 and the short-wave first folding mirror 14 are all coated with a high-reflection film.

[0062] The beam splitter prism 5 transmits short-wave infrared and reflects visible light, so as to separate the short-wave infrared channel from the visible light channel. The base material of the beam splitter prism 5 is selected as a visible light material.

[0063] The medium-wave infrared channel adopts a secondary imaging structure to achieve matching between the system exit pupil and the detector aperture, and the cold aperture efficiency is 100%, which reduces the system's own radiation; the medium-wave fifth lens 12 is used to achieve high and low temperature environment compensation for the medium-wave infrared channel, and can achieve clear imaging in the full temperature range;

[0064] The short-wave infrared channel and the visible light channel both adopt a one-time imaging structure, with a small number of lenses and a high system transmittance;

[0065] The short-wave first lens 15, the short-wave second lens 16, the short-wave third lens 17 and the short-wave fourth lens 18 are integrally used as a short-wave channel focusing group, which is used to achieve high and low temperature environment compensation of the short-wave infrared channel, and can achieve clear imaging in the full temperature range;

[0066] Furthermore, the first visible light lens 20, the second visible light lens 21, the third visible light lens 22 and the fourth visible light lens 23 are integrally used as a visible light channel focusing group, which is used to achieve high and low temperature environment compensation of the visible light channel, and can achieve clear imaging in the full temperature range;

[0067] In this embodiment, a compact long-focal-length common-aperture multi-sensor optoelectronic payload optical system is provided, with an optical system aperture of 250 mm, a focal length of a medium-wave infrared channel of 1000 mm, suitable for a refrigerated medium-wave infrared detector with a resolution of 1280×1024, a pixel pitch of 12 μm×12 μm, and a cold screen F number of F4; a focal length of a short-wave infrared channel of 1920 mm, suitable for a short-wave detector with a resolution of 640×512 and a pixel pitch of 15 μm×15 μm; a focal length of a visible light channel of 1125 mm, suitable for a visible light detector with a resolution of 1920×1080 and a pixel pitch of 6.9 μm×6.9 μm;

[0068] In this embodiment, the preferred primary reflector 1 has a parabolic surface and is made of microcrystalline glass, and the preferred secondary reflector 2 has a hyperbolic surface and is made of microcrystalline glass;

[0069] The preferred beam splitter 4 in this embodiment is placed at an angle of 45° to the optical axis, made of single crystal silicon, 4 mm thick, with a beam splitter film and an anti-reflection film coated on the front and back surfaces, respectively, with a transmission of 3.7 μm to 4.8 μm and a reflection of 0.4 μm to 1.7 μm;

[0070] The preferred material of the beam splitter prism 5 in this embodiment is H-K9L, with a thickness of 20 mm, a transmission of 1.05 μm to 1.7 μm, and a reflection of 0.4 μm to 0.9 μm;

[0071] In this embodiment, the preferred medium-wavelength first lens 6, medium-wavelength second lens 7, medium-wavelength third lens 9, medium-wavelength fourth lens 10 and medium-wavelength fifth lens 12 are all made of silicon and germanium materials;

[0072] The preferred medium-wave first lens 6 adopts a double cone surface to compensate for the astigmatism caused by the beam splitter 4, wherein the radius of curvature in the meridian direction is 63.164 mm, and the radius of curvature in the sagittal direction is 63.036 mm;

[0073] The biconical surface mentioned in the preferred medium-wavelength first lens 6 is expressed as follows:

[0074]

[0075] in:

[0076]

[0077] Where Z is the sagittal height, c is the radius of curvature, k is the cone coefficient, x is the meridian direction, and y is the sagittal direction.

[0078] The preferred MW fifth lens 12 is used as a MW infrared channel focusing lens to achieve high and low temperature environment compensation for the MW infrared channel, and can achieve clear imaging within the range of -40°C to +60°C;

[0079] The preferred short-wave first lens 15, the short-wave second lens 16, the short-wave third lens 17 and the short-wave fourth lens 18 are made of flint glass and crown glass, and are used as a short-wave infrared channel focusing group as a whole to achieve high and low temperature environment compensation of the short-wave infrared channel, and can achieve clear imaging within the range of -40°C to +60°C;

[0080] Preferably, the first visible light lens 20, the second visible light lens 21, the third visible light lens 22 and the fourth visible light lens 23 are made of flint glass and crown glass, and as a whole serve as a visible light channel focusing group, which is used to achieve high and low temperature environment compensation of the visible light channel, and can achieve clear imaging within the range of -40°C to +60°C;

[0081] The preferred materials of the medium-wave first folding mirror 8, the medium-wave second folding mirror 11 and the short-wave first folding mirror 14 are all H-K9L, coated with a high-reflection film;

[0082] Table 1 shows the specific parameter data of each lens in the optical system:

[0083]

[0084]

[0085]

[0086] Note: The units of dimensions in the table are: millimeters;

[0087] The aspheric surfaces mentioned in the above lenses are all even-order aspheric surfaces, and their expressions are as follows:

[0088]

[0089] Where Z is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of r along the optical axis, c is the radius of curvature, k is the cone coefficient, and A, B, and C are the aspheric coefficients;

[0090] Figure 2 to Figure 4 They are respectively the MTF curve graph of the medium-wave infrared channel, the MTF curve graph of the short-wave infrared channel and the MTF curve graph of the visible light channel in this embodiment. It can be seen from the figures that the medium-wave infrared channel, the short-wave infrared channel and the visible light channel all have high imaging quality, meeting the needs of accurate target detection.

[0091] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention of the utility model.

Claims

1. A compact long focal length common aperture multi-sensor optoelectronic payload optical system, It is characterized in that include: A primary reflector (1), a secondary reflector (2), a fast reflector (3), a beam splitter (4), a beam splitter prism (5), a first medium wave lens (6), a second medium wave lens (7), a first medium wave folding mirror (8), a third medium wave lens (9), a fourth medium wave lens (10), a second medium wave folding mirror (11), a fifth medium wave lens (12), a medium wave detector (13), a first short wave folding mirror (14), a first short wave lens (15), a second short wave lens (16), a third short wave lens (17), a fourth short wave lens (18), a short wave detector (19), a first visible light lens (20), a second visible light lens (21), a third visible light lens (22), a fourth visible light lens (23), and a visible light detector (24); The secondary reflector (2) is arranged on one side of the primary reflector (1), and the remaining components are arranged on a side opposite to the reflector (2); on this side, a medium wave detector (13), a medium wave fifth lens (12) and a medium wave second folding mirror (11) are arranged in sequence from bottom to top; a medium wave fourth lens (10), a medium wave third lens (9) and a medium wave first folding mirror (8) are arranged in sequence on one side of the medium wave second folding mirror (11); and a medium wave second lens (7), a medium wave first lens (6), a beam splitter (4) and a quick reflection mirror (3) are arranged in sequence below the medium wave first folding mirror (8) A beam splitter (4) and a short-wave first folding mirror (14) are sequentially arranged on a side of the beam splitter (4) away from the medium-wave detector (13); a visible light first lens (20), a visible light second lens (21), a visible light third lens (22), a visible light fourth lens (23) and a visible light detector (24) are sequentially arranged below the beam splitter prism (5); and a short-wave first lens (15), a short-wave second lens (16), a short-wave third lens (17), a short-wave fourth lens (18) and a short-wave detector (19) are sequentially arranged below the short-wave first folding mirror (14).

2. The compact long focal length common aperture multi-sensor optoelectronic payload optical system according to claim 1, It is characterized in that The quick reflection mirror (3), the beam splitter (4), the medium-wave first folding mirror (8) and the medium-wave second folding mirror (11) are all arranged in an inclined manner.

3. The compact long focal length common aperture multi-sensor optoelectronic payload optical system according to claim 2, It is characterized in that The included angle between the fast reflection mirror (3) and the optical axis is 45°.

4. The compact long focal length common aperture multi-sensor optoelectronic payload optical system according to claim 2, It is characterized in that The included angle between the beam splitter (4) and the optical axis is 45°.

5. The compact long focal length common aperture multi-sensor optoelectronic payload optical system according to claim 2, It is characterized in that The included angle between the medium wave first folding mirror (8) and the optical axis is 45°.

6. The compact long focal length common aperture multi-sensor optoelectronic payload optical system according to claim 2, It is characterized in that The included angle between the medium-wave second folding mirror (11) and the optical axis is 45°.

7. The compact long focal length common aperture multi-sensor optoelectronic payload optical system according to claim 1, It is characterized in that The surface type combinations of the primary reflector (1) and the secondary reflector (2) include the following: The primary reflector (1) is a parabola, and the secondary reflector (2) is a hyperbolic surface or a high-order aspheric surface; The primary reflector (1) is a hyperbolic surface, and the secondary reflector (2) is a hyperbolic surface or a high-order aspherical surface; The primary reflector (1) is a high-order aspherical surface, and the secondary reflector (2) is a mirror spherical surface.

8. The compact long focal length common aperture multi-sensor optoelectronic payload optical system according to claim 1, It is characterized in that The two surfaces of the beam splitter (4) are respectively coated with a beam splitting film and an anti-reflection film.

9. The compact long focal length common aperture multi-sensor optoelectronic payload optical system according to claim 1, It is characterized in that The medium-wave first folding mirror (8), the medium-wave second folding mirror (11) and the short-wave first folding mirror (14) are all coated with a high-reflection film.

10. The compact long focal length common aperture multi-sensor optoelectronic payload optical system according to claim 1, It is characterized in that The medium-wave first lens (6) is a biconical lens.

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