Multispectral common-path multichannel polarization detection optical system

Abstract

A multi-spectrum common-optical-path multichannel polarization detection optical system comprises a main optical path sharing module, a color separation film module, a visible spectrum dual-channel module, a short-wave spectrum dual-channel module and a medium-wave spectrum dual-channel module. The light incidence direction is defined as the front; specifically, the main optical path sharing module is arranged at the foremost end of the system; the optical axis of the main optical path sharing module is marked as a main optical axis; the color separation film module is arranged at the rear end of the main light path sharing module and shares the same optical axis with the main light path sharing module, and light rays passing through the main light path sharing module are subjected to spectrum band screening and then are respectively sent into the visible spectrum band dual-channel module, the short spectrum band dual-channel module and the medium spectrum band dual-channel module for screening; the optical axes of the visible spectrum band dual-channel module, the short spectrum band dual-channel module and the medium spectrum band dual-channel module are all perpendicular to the main optical axis, and the light rays of the corresponding spectrum bands screened by the color separation film module are received respectively, and imaging of the corresponding spectrum bands is carried out.

Description

Technical Field

[0001] This invention relates to a multi-spectral band common optical path multi-channel polarization detection optical system, belonging to the field of space camera optical detection technology. Background Technology

[0002] In recent years, the deployment of commercial remote sensing satellites has increased both domestically and internationally, representing a growing trend in the commercialization of the space sector. However, with the increasing number of commercial remote sensing satellites in Earth orbit, the risk of space collisions has risen sharply, posing a significant threat to the normal operation of these satellites. Therefore, the ability to capture and detect faint targets on in-orbit commercial remote sensing satellites and space debris is crucial for ensuring space security. Currently, there are still shortcomings in the accurate capture and detection of faint targets on in-orbit commercial satellites and space debris, both domestically and internationally. Existing space target identification and detection cameras have small apertures and narrow spectral bands, making them unable to capture and detect small-sized faint targets on space debris in real time. This seriously affects the security of the development of commercial remote sensing satellites in orbit, thus highlighting the urgent need for real-time detection in this area. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a multi-spectral band common optical path multi-channel polarization detection optical system, which has the advantages of realizing the fusion of multiple broadband bands, integrated polarization detection, low distortion and high imaging quality, and meets the requirements of high-precision and accurate acquisition of faint targets in space and detection of photometric energy.

[0004] The technical solution of this invention is: a multi-spectral band common-path multi-channel polarization detection optical system, comprising:

[0005] The system includes a main optical path shared module, a dichroic filter module, a visible spectrum dual-channel module, a shortwave spectrum dual-channel module, and a midwave spectrum dual-channel module; the system's light incident direction is defined as the front of the system; specifically:

[0006] The main optical path shared module is placed at the front of the system to realize multi-spectral integration and coordination of the optical system; the optical axis of the main optical path shared module is referred to as the main optical axis.

[0007] The color separation module is located at the rear end of the main optical path shared module and on the main optical axis. After the light passing through the main optical path shared module is filtered by spectrum, it is sent to the visible spectrum dual-channel module, the short-wave spectrum dual-channel module, and the mid-wave spectrum dual-channel module for further filtering.

[0008] The optical axes of the visible spectrum dual-channel module, the shortwave spectrum dual-channel module, and the midwave spectrum dual-channel module are all perpendicular to the main optical axis. They receive light from the corresponding spectral bands selected by the dichroic filter module and perform imaging of the corresponding spectral bands.

[0009] Preferably, the main optical path shared module includes: a primary mirror and a secondary mirror;

[0010] The primary mirror is located between the secondary mirror and the dichroic filter module; the surfaces of the secondary mirror and the primary mirror that face each other are reflective surfaces, and a through hole is provided in the center of the primary mirror. When the primary mirror reflects the incident light to the secondary mirror, the secondary mirror reflects the light and it passes through the through hole of the primary mirror to reach the dichroic filter module.

[0011] The color separation module includes: a first color separation and a second color separation arranged from front to back.

[0012] Preferably, the visible spectrum dual-channel module includes: a visible polarizing beam splitter, two identical first visible light lenses, two identical second visible light lenses, and two identical third visible light lenses; specifically:

[0013] Light rays pass through the primary mirror and secondary mirror and are incident on the first dichroic filter. The visible light is reflected by the front surface of the first dichroic filter. The visible light reflected by the first dichroic filter is split into two paths by a visible polarizing beam splitter. The two beams are perpendicular to each other, and the lens arrangement in the two paths is exactly the same. Each beam passes through the first visible light lens, the second visible light lens, the third visible light lens and the cover glass in sequence and then converges on the image plane.

[0014] Preferably, the short-wavelength dual-channel module includes: a short-wavelength polarizing beam splitter, two identical short-wavelength first lenses, two identical short-wavelength second lenses, two identical short-wavelength third lenses, and two identical short-wavelength fourth lenses; specifically:

[0015] Light passes through the primary mirror, secondary mirror, and first dichroic filter before entering the second dichroic filter. The short-wavelength light is reflected by the front surface of the second dichroic filter to the short-wave polarizing beam splitter. The short-wave polarizing beam splitter splits the light into two beams that are perpendicular to each other. The lenses in the two beams are arranged in the same way. Each beam passes through the first short-wavelength lens, the second short-wavelength lens, the third short-wavelength lens, the fourth short-wavelength lens, and the cover glass in sequence before converging on the image plane.

[0016] Preferably, the mid-wave dual-channel module includes: a first folding mirror, a second folding mirror, a third folding mirror, a mid-wave first lens, a mid-wave polarizing beam splitter, two identical mid-wave second lenses, two identical mid-wave third lenses, two identical mid-wave fourth lenses, and two identical mid-wave fifth lenses; specifically:

[0017] After light passes through the primary mirror, secondary mirror, first dichroic filter, and second dichroic filter, it is reflected by the first folding mirror to the second folding mirror, then by the second folding mirror to the third folding mirror, and finally by the third folding mirror to the first mid-wave lens. After being transmitted through the first mid-wave lens, it is incident on the mid-wave polarizing beam splitter to achieve two beam splits. The two beam splits are perpendicular to each other, and the lenses in the two beam splits are identical. Each beam splits sequentially through the second mid-wave lens, the third mid-wave lens, the fourth mid-wave lens, the fifth mid-wave lens, the cover glass, and the filter before converging on the image plane.

[0018] Preferably, the operating spectral band of the optical system is:

[0019] The visible spectrum ranges from 0.4 μm to 0.9 μm, the shortwave spectrum ranges from 1.1 μm to 1.7 μm, and the midwave spectrum ranges from 3.7 μm to 5 μm.

[0020] Preferably, the reflecting surfaces of the primary mirror and the secondary mirror are both quadratic curved surfaces; the first dichroic filter and the second dichroic filter are both planar.

[0021] Both the primary and secondary mirrors have reflective coatings on their reflective surfaces, with a reflectivity greater than 0.97 in the 0.4μm to 5μm spectral range.

[0022] The front surface of the first dichroic filter is a reflective surface with a reflection spectrum of 0.4 μm to 0.9 μm, and the transmission spectrum of the rear surface of the first dichroic filter is 1.1 μm to 1.7 μm and 3.7 μm to 5 μm.

[0023] The front surface of the second dichroic filter is a reflective surface with a reflection spectrum of 1.1 μm to 1.7 μm, and the rear surface of the second dichroic filter 2 has a transmission spectrum of 3.7 μm to 5 μm.

[0024] The primary mirror material is SiC; the secondary mirror material is microcrystalline.

[0025] The materials for the first and second color separations are ZNSE.

[0026] Preferably, in the visible spectrum dual-channel module:

[0027] The first visible light lens, the second visible light lens, and the third visible light lens are all spherical.

[0028] The first visible light lens, the second visible light lens, and the third visible light lens are coated with anti-reflection coatings, and the transmittance in the 0.4μm to 0.9μm spectral range is greater than 0.99.

[0029] The visible polarizing beam splitter has a polarizing film coated on its inclined surface, with a polarization degree ≥ 500:1;

[0030] The material of the first visible light lens is N-FK58, the material of the second visible light lens is N-KZFS2, and the material of the third visible light lens is N-FK58;

[0031] It can be seen that the material of the polarizing beam splitter is H-ZF3.

[0032] Preferably, in the shortwave band dual-channel module:

[0033] The front surface of the first shortwave lens is cylindrical, and the rear surface is planar; the second, third, and fourth shortwave dual-channel lenses are all spherical.

[0034] The first short-wavelength lens, the second short-wavelength lens, the third short-wavelength lens, and the fourth short-wavelength lens are coated with anti-reflective coatings, and the transmittance is greater than 0.99 in the 1.1μm to 1.7μm spectral range.

[0035] The inclined surface of the short-wave polarizing beam splitter is coated with a polarizing film, with a polarization degree ≥500:1;

[0036] The first shortwave lens is made of SILICA, the second shortwave lens is made of N-LASF31A, the third shortwave lens is made of N-SF66, and the fourth shortwave lens is made of N-LASF31A.

[0037] The material of the short-wave polarization beam splitter is H-ZF3.

[0038] Preferably, in the mid-wave spectrum dual-channel module:

[0039] The first, second, third, fourth, and fifth lenses of the medium-wave wave are all spherical; the first, second, and third folding mirrors of the medium-wave dual-channel are all planar.

[0040] The first, second, third, fourth, and fifth medium-wave lenses are coated with anti-reflective coatings, and the transmittance is greater than 0.99 in the 3.7μm to 5μm spectral range.

[0041] The first, second, and third refracting mirrors are coated with reflective films, and their reflectivity is greater than 0.97 in the 3.7μm to 5μm spectral range.

[0042] Mid-wave polarizing beam splitter with a polarizing film coated on the inclined surface, polarization degree ≥300:1

[0043] The first, second, and third folding mirrors are made of microcrystalline materials.

[0044] The medium-wave first lens is made of GERMANIUM, the medium-wave second lens is made of SILICON, the medium-wave third lens is made of ZNSE, the medium-wave fourth lens is made of ZNSE, and the medium-wave fifth lens is made of SILICON.

[0045] The medium-wave polarization beam splitter is made of SILICON.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] (1) The system of the present invention has multiple wide-band integrated detection and imaging capabilities, and can realize polarization detection imaging of 6 channels in the spectral range of 0.4μm~0.9μm, 1.1μm~1.7μm, and 3.7μm~5μm. It solves the problem of real-time fusion imaging of multiple spectral bands and multiple channels of current space target detection cameras, and improves the polarization detection imaging capability of space target detection cameras for small-sized space targets in multiple wide-band ranges.

[0048] (2) The system of the present invention has good imaging quality, solves the problems of low energy concentration and large distortion of the optical system of the current space target detection camera, and improves the high-precision acquisition and photometric detection capability of the space target detection camera for small-sized targets. Attached Figure Description

[0049] Figure 1 This is a diagram of a multi-band common-path polarization detection optical system according to the present invention;

[0050] Figure 2 (a) is an optical path diagram of the visible light dual-channel module of the optical system of the present invention;

[0051] Figure 2 (b) is a partial beam splitting diagram of the visible light dual-channel module of the optical system of the present invention;

[0052] Figure 3 (a) is an optical path diagram of the short-wavelength dual-channel module of the optical system of the present invention;

[0053] Figure 3 (b) is a partial beam splitting diagram of the short-wave dual-channel module of the optical system of the present invention;

[0054] Figure 4 (a) is the optical path diagram of the wave-wave dual-channel module in the optical system of the present invention;

[0055] Figure 4 (b) is a partial view of the wave dual-channel module in the optical system of the present invention;

[0056] Figure 4 (c) is a partial beam splitting diagram of the wave-wave dual-channel design in the optical system of the present invention;

[0057] Figure 5 This is a diagram showing the energy concentration of the visible dual-channel module of the optical system of the present invention in each field of view;

[0058] Figure 6 This is a diagram showing the energy concentration of the short-wavelength dual-channel module of the optical system of the present invention in each field of view;

[0059] Figure 7This is a diagram showing the energy concentration of the wave-wave dual-channel module in the optical system of this invention in each field of view;

[0060] Figure 8 This is a point diagram of the visible dual-channel module of the optical system of the present invention in each field of view;

[0061] Figure 9 This is a point diagram of the short-wavelength dual-channel module of the optical system of the present invention in each field of view;

[0062] Figure 10 This is a point diagram of the wave-wave dual-channel module in the optical system of the present invention in each field of view;

[0063] Figure 11 The image shows the grid distortion of the visible dual-channel module of the optical system of the present invention in each field of view.

[0064] Figure 12 This is a grid distortion diagram of the short-wavelength dual-channel module of the optical system of the present invention in each field of view;

[0065] Figure 13 This is a grid distortion diagram of the wave-wave dual-channel module in the optical system of this invention in each field of view;

[0066] Figure 14 This is a spectrogram of the rear module of a multi-band common-path polarization detection optical system according to the present invention. Detailed Implementation

[0067] The objective of this invention is achieved through the following technical solution: a multi-spectral band common-path multi-channel polarization detection optical system, comprising:

[0068] Shared modules for the main optical path: primary mirror 11, secondary mirror 12;

[0069] Color separation module: First color separation 21, Second color separation 22;

[0070] Visible spectrum dual-channel module (two channels are the same): visible polarization beam splitter prism 301, visible light first lens 302, visible light second lens 303, visible light third lens 304;

[0071] Shortwave band dual-channel module (two channels are the same): shortwave polarization beam splitter prism 401, shortwave first lens 402, shortwave second lens 403, shortwave third lens 404, shortwave fourth lens 405;

[0072] Mid-wave spectrum dual-channel module (two channels are the same): First folding mirror 501, Second folding mirror 502, Third folding mirror 503, Mid-wave first lens 504, Mid-wave polarizing beam splitter prism 505, Mid-wave second lens 506, Mid-wave third lens 507, Mid-wave fourth lens 508, Mid-wave fifth lens 509;

[0073] The direction of light incidence is defined as forward.

[0074] like Figure 1 , Figure 14 , Figure 2 (a) and Figure 2 As shown in (b):

[0075] The visible light emitted by the target in this optical system is incident on the front surface of the first dichroic filter 21 after passing through the primary mirror 11 and the secondary mirror 12. After being reflected, the visible light reflected by the first dichroic filter 21 is split into two paths by the visible polarizing beam splitter 301. The two beams are perpendicular to each other. The lenses with the same relative position after splitting are completely identical. The two beams pass through the first visible light lens 302, the second visible light lens 303, the third visible light lens 304 and the cover glass in sequence and finally converge on the image plane Image of the visible spectrum dual-channel module.

[0076] like Figure 1 , Figure 14 , Figure 3 (a) and Figure 3 As shown in (b):

[0077] The light emitted by the short-wave dual-channel target in this optical system passes through the primary mirror 11, secondary mirror 12, and first dichroic filter 21 before entering the second dichroic filter 22. After being reflected by the front surface of the second dichroic filter 22, it is split into two beams by the short-wave polarizing beam splitter 401. The two beams are perpendicular to each other, and the lenses with the same relative position after splitting are identical. Each beam passes sequentially through the first short-wave lens 402, the second short-wave lens 403, the third short-wave lens 404, the fourth short-wave lens 405, and the cover glass, and finally converges on the image plane Image of the short-wave dual-channel.

[0078] like Figure 1 , Figure 14 , Figure 4 (a) Figure 4 (b) Figure 4 As shown in (c):

[0079] In this optical system, the light rays radiated by the mid-wave dual-channel target pass through the primary mirror 11, secondary mirror 12, first dichroic filter 21, and second dichroic filter 22, are incident on the first refracting mirror 501, reflected to the second refracting mirror 502, and then reflected again by the third refracting mirror 503. After being transmitted through the mid-wave first lens 504, they are incident on the mid-wave polarizing beam splitter 505. The mid-wave polarizing beam splitter 505 achieves two-way beam splitting, and the two beam splits are perpendicular to each other. The lenses with the same relative position after beam splitting are identical. Each beam splitting passes sequentially through the mid-wave second lens 506, mid-wave third lens 507, mid-wave fourth lens 508, mid-wave fifth lens 509, cover glass, and filter, and finally converges on the image plane Image of the mid-wave dual-channel.

[0080] The parameter inputs for the above catadioptric optical system are as follows:

[0081] Operating spectral bands: Visible (B1): 0.4μm~0.9μm, Shortwave Infrared (B2): 1.1μm~1.7μm, Midwave Infrared (B3): 3.7μm~5μm;

[0082] The entrance pupil diameter is 500 mm.

[0083] Focal length: Visible light dual channel: 1833mm, short-wave infrared dual channel: 2445mm, mid-wave infrared dual channel: 970.72mm; Acceptable deviation during assembly and adjustment is ±1%;

[0084] Field of view: Visible: 0.15°×0.15°, Shortwave infrared: 0.15°×0.15°, Midwave infrared: 0.22°×0.22°;

[0085] The distance between the vertex of the primary mirror and the vertex of the secondary mirror is 511mm, the distance between the vertex of the secondary mirror and the center point of the first dichroic mirror is 656mm, and the distance between the center point of the first dichroic mirror and the center point of the second dichroic mirror is 60mm.

[0086] In the aforementioned catadioptric optical system, the reflecting surfaces of the primary mirror 11 and the secondary mirror 12 are both quadratic curved surfaces; the primary mirror is located between the secondary mirror and the dichroic filter module; the surfaces of the secondary mirror and the primary mirror facing each other are reflecting surfaces; a through hole is provided in the center of the primary mirror; when the primary mirror reflects the incident light to the secondary mirror, the secondary mirror reflects the light and it passes through the through hole of the primary mirror to reach the dichroic filter module; the first dichroic filter 21 and the second dichroic filter 22 are both planar.

[0087] In the visible dual-channel system, the first visible light lens 302, the second visible light lens 303, and the third visible light lens 304 are all spherical.

[0088] In the shortwave dual-channel, the front surface of the first shortwave lens 402 is cylindrical and the rear surface is planar; the second shortwave lens 403, the third shortwave lens 404, and the fourth shortwave lens 405 are all spherical.

[0089] In the medium-wave dual-channel system, the first medium-wave lens 504, the second medium-wave lens 506, the third medium-wave lens 507, the fourth medium-wave lens 508, and the fifth medium-wave lens 509 are all spherical; the first folding mirror 501, the second folding mirror 502, and the third folding mirror 503 of the medium-wave dual-channel system are all planar.

[0090] In the above-mentioned catadioptric optical system, the front surface of the first dichroic filter 21 is a reflective surface with a reflection spectrum of 0.4μm to 0.9μm (B1), and the rear surface of the first dichroic filter 21 transmits 1.1μm to 1.7μm (B2) and 3.7μm to 5μm (B3); the front surface of the second dichroic filter 22 is a reflective surface with a reflection spectrum of 1.1μm to 1.7μm (B2), and the rear surface of the second dichroic filter 22 transmits 3.7μm to 5μm (B3).

[0091] In the aforementioned catadioptric optical system, both the primary and secondary mirrors are coated with reflective films, and the reflectivity is greater than 0.97 in the 0.4μm to 5μm spectral range.

[0092] In the mid-wave spectrum dual-channel type, the first refracting mirror 501, the second refracting mirror 502, and the third refracting mirror 503 are all coated with reflective films, and the reflectivity is greater than 0.97 in the 3.7μm to 5μm spectral range;

[0093] In the visible spectrum dual-channel, the first visible light lens, the second visible light lens, and the third visible light lens are coated with anti-reflection films, and the transmittance in the 0.4μm to 0.9μm spectral range is greater than 0.99.

[0094] In the shortwave dual-channel, the first shortwave lens, the second shortwave lens, the third shortwave lens, and the fourth shortwave lens are all coated with antireflective coatings, and the transmittance in the 1.1μm to 1.7μm spectral range is greater than 0.99.

[0095] In the dual-channel mid-wave band, the first, second, third, fourth, and fifth mid-wave lenses are all coated with anti-reflection films, and the transmittance in the 3.7μm to 5μm spectral range is greater than 0.99.

[0096] In the aforementioned catadioptric optical system, the visible polarizing beam splitter 301 has a slanted surface coated with a polarizing film with a polarization degree ≥ 500:1; the short-wave polarizing beam splitter 401 has a slanted surface coated with a polarizing film with a polarization degree ≥ 500:1; and the mid-wave polarizing beam splitter 505 has a slanted surface coated with a polarizing film with a polarization degree ≥ 300:1.

[0097] In the aforementioned catadioptric optical system, the rear surface of the first visible light lens is coated with a cutoff film, which transmits a spectrum of 0.4μm to 0.9μm; the rear surface of the first short-wavelength lens is coated with a cutoff film, which transmits a spectrum of 1.1μm to 1.7μm; and the rear surface of the second mid-wavelength lens is coated with a cutoff film, which transmits a spectrum of 3.7μm to 5μm.

[0098] In the aforementioned catadioptric optical system, the primary mirror is made of SiC; the secondary mirror, first refracting mirror 501, second refracting mirror 502, and third refracting mirror 503 are made of microcrystalline material; the first dichroic filter 21 and the second dichroic filter 22 are made of ZNSE; in the visible dual-channel system, the visible light first lens is made of N-FK58, the visible light second lens is made of N-KZFS2, and the visible light third lens is made of N-FK58; in the short-wave dual-channel system, the short-wave first lens is made of SILICA, the short-wave second lens is made of N-LASF31A, and the short-wave third lens is made of N-FK58. The material of the third lens for the short-wavelength wave is N-SF66, and the material of the fourth lens for the short-wavelength wave is N-LASF31A. In the mid-wave dual-channel configuration, the material of the first lens for the mid-wavelength wave is GERMANIUM, the material of the second lens for the mid-wavelength wave is SILICON, the material of the third lens for the mid-wavelength wave is ZNSE, the material of the fourth lens for the mid-wavelength wave is ZNSE, and the material of the fifth lens for the mid-wavelength wave is SILICON. The material of the visible polarization beam splitter is H-ZF3, the material of the short-wavelength polarization beam splitter is H-ZF3, and the material of the mid-wavelength polarization beam splitter is SILICON.

[0099] Example:

[0100] The following is a detailed description of preferred embodiments of the present invention with reference to the accompanying drawings. These embodiments are provided to enable a clearer understanding of the specific embodiments of the present invention. The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0101] This embodiment provides a multi-band common-path multi-channel polarization detection optical system with an entrance pupil diameter of 500 mm. The visible spectrum ranges from 0.4 μm to 0.9 μm, the short-wave spectrum from 1.1 μm to 1.7 μm, and the mid-wave spectrum from 3.7 μm to 5 μm. The focal lengths are 1833 mm for the visible spectrum, 2445 mm for the short-wave spectrum, and 970.72 mm for the mid-wave spectrum. The field of view is 0.15° × 0.15° for the visible spectrum, 0.15° × 0.15° for the short-wave spectrum, and 0.22° × 0.22° for the mid-wave spectrum.

[0102] like Figure 1 and Figure 14 As shown, the system components include a primary mirror 11, a secondary mirror 12, a first dichroic filter 21, a second dichroic filter 22, a visible polarizing beam splitter 301, a visible light first lens 302, a visible light second lens 303, a visible light third lens 304, a short-wave polarizing beam splitter 401, a short-wave first lens 402, a short-wave second lens 403, a short-wave third lens 404, a short-wave fourth lens 405, a mid-wave first folding mirror 501, a mid-wave second folding mirror 502, a mid-wave third folding mirror 503, a mid-wave first lens 504, a mid-wave polarizing beam splitter 505, a mid-wave second lens 506, a mid-wave third lens 507, a mid-wave fourth lens 508, and a mid-wave fifth lens 509.

[0103] The visible light rays from the dual-channel target radiation in this optical system are incident on the front surface of the first dichroic filter 21 after being reflected by the primary mirror 11 and the secondary mirror 12. The light is then split into two paths by the visible polarizing beam splitter 301. The two lenses with the same relative position after splitting are completely identical. The two beams pass through the first visible light lens 302, the second visible light lens 303, the third visible light lens 304 and the cover glass in sequence and finally converge on the image plane Image.

[0104] The short-wave dual-channel target radiation of this optical system is incident on the front surface of the second dichroic filter 22 after passing through the primary mirror 11, secondary mirror 12, and first dichroic filter 21. After reflection, it is split into two paths by the short-wave polarizing beam splitter 401. The two lenses with the same relative position after splitting are completely identical. The two split beams pass through the first short-wave lens 402 (cylindrical), the second short-wave lens 403, the third short-wave lens 404, the fourth short-wave lens 405 and the cover glass in sequence and finally converge on the image plane Image.

[0105] In this optical system, the light rays radiated by the mid-wave dual-channel target pass through the primary mirror 11, secondary mirror 12, first dichroic filter 21, and second dichroic filter 22, are incident on the first refracting mirror 501, reflected to the second refracting mirror 502, and then reflected again by the third refracting mirror 503. After being transmitted through the first mid-wave lens 504, they are incident on the mid-wave polarizing beam splitter prism 505 to achieve two-way beam splitting. The two lenses with the same relative position after beam splitting are completely identical. The two beams pass sequentially through the second mid-wave lens 506, the third mid-wave lens 507, the fourth mid-wave lens 508, the fifth mid-wave lens 509, the cover glass, and the filter, and finally converge on the image plane Image.

[0106] By optimizing the quadratic coefficients of the primary and secondary mirror surfaces, the radius of curvature of the vertices of each optical element, the thickness of the lens elements themselves, and the air gap between each optical element, the imaging quality of the optical system is brought close to the diffraction limit, while the system volume is compressed to within Ф501.8mm×830mm.

[0107] The primary mirror is made of SiC with an antireflective coating, and has a reflectivity of >97% in the B1 (0.4μm~0.9μm), B2 (1.1μm~1.7μm), and B3 (3.7μm~5μm) spectral ranges.

[0108] The secondary mirror is made of microcrystalline material with an antireflective coating on the surface, and has a reflectivity of >97% in the B1 (0.4μm~0.9μm), B2 (1.1μm~1.7μm), and B3 (3.7μm~5μm) spectral ranges.

[0109] The first color separator is made of ZNSE, with a reflective coating on its front surface. The reflectivity of B1 (0.4μm~0.9μm) is >97%, and the transmittance of B2 (1.1μm~1.7μm) and B3 (3.7μm~5μm) is >99%.

[0110] The second dichroic film is made of ZNSE, with a reflective coating on the front surface. It has a reflectivity of >97% (B2, 1.1μm to 1.7μm) and a transmittance of >99% (B3, 3.7μm to 5μm).

[0111] The visible polarizing beam splitter is made of H-ZF3 material, with antireflection coatings on both the incident and exit surfaces. The transmittance is >99% in the 0.4μm to 0.9μm spectral range. The inclined surface is coated with a polarizing beam splitter film with an extinction ratio of 500:1.

[0112] The short-wave polarizing beam splitter is made of H-ZF3 material, with antireflection coatings on both the incident and exit surfaces. The transmittance is >99% in the 1.1μm to 1.7μm spectral range. The inclined surface is coated with a polarizing beam splitter with an extinction ratio of 500:1.

[0113] The medium-wave polarizing beam splitter is made of silicon. Both the incident and exit surfaces are coated with antireflection films, and the transmittance is >99% in the 3.7μm to 5μm spectral range. The inclined surface is coated with a polarizing beam splitter film with an extinction ratio of 300:1.

[0114] The visible light first lens is made of N-FK58, with anti-reflection coatings on both the front and rear surfaces, and a transmittance of >99% in the 0.4μm to 0.9μm spectral range.

[0115] The visible light second lens is made of N-KZFS2, with antireflection coatings on both the front and rear surfaces, and a transmittance of >99% in the 0.4μm to 0.9μm spectral range.

[0116] The visible light third lens is made of N-FK58, with antireflection coatings on both the front and rear surfaces, and a transmittance of >99% in the 0.4μm to 0.9μm spectral range.

[0117] The shortwave first lens (cylindrical lens) is made of SILICA (fused silica), with antireflective coatings on both the front and rear surfaces, and a transmittance of >99% in the 1.1μm to 1.7μm spectral range.

[0118] The shortwave second lens is made of N-LASF31A material, with antireflective coatings on both the front and rear surfaces, and a transmittance of >99% in the 1.1μm to 1.7μm spectral range.

[0119] The shortwave third lens is made of N-SF66, with antireflective coatings on both the front and rear surfaces, and has a transmittance of >99% in the 1.1μm to 1.7μm spectral range.

[0120] The fourth shortwave lens is made of N-LASF31A material, with antireflective coatings on both the front and rear surfaces, and a transmittance of >99% in the 1.1μm to 1.7μm spectral range.

[0121] The medium-wave first lens is made of germanium, with anti-reflection coatings on both the front and back surfaces, and a transmittance of >99% in the 3.7μm to 5μm spectral range.

[0122] The medium-wave second lens is made of silicon, with antireflective coatings on both the front and rear surfaces, and a transmittance of >99% in the 3.7μm to 5μm spectral range.

[0123] The medium-wave third lens is made of ZNSE, with antireflective coatings on both the front and rear surfaces, and has a transmittance of >99% in the 3.7μm to 5μm spectral range.

[0124] The material of the mid-wave fourth lens is ZNSE, and both the front and rear surfaces are coated with anti-reflection films. The transmittance is >99% in the 3.7μm to 5μm spectral range.

[0125] The fifth lens for medium-wave wavelength is made of silicon, with antireflective coatings on both the front and back surfaces. It has a transmittance of >99% in the 3.7μm to 5μm spectral range.

[0126] The first, second, and third folding mirrors of the medium wave are all made of microcrystalline material, and their surfaces are coated with antireflective coatings, with a reflection B3 (3.7μm~5μm) and a reflectivity >97%.

[0127]

[0128]

[0129] like Figure 5 As shown, the energy concentration of the visible dual-channel module of the optical system of the present invention is shown in the diagram of each field of view. The energy concentration of each field of view within the range of 9μm×9μm is greater than 0.75.

[0130] like Figure 6 As shown, the energy concentration diagram of the short-wave dual-channel module of the optical system of the present invention is shown in each field of view. The energy concentration of each field of view in the range of 30μm×30μm is greater than 0.81.

[0131] like Figure 7 As shown, the energy concentration diagram of the wave-wave dual-channel module in the optical system of the present invention is shown in each field of view. The energy concentration of each field of view within the range of 30μm×30μm is greater than 0.68.

[0132] like Figure 8The diagram shows the dot plot of the visible dual-channel module of the optical system of the present invention in each field of view. The maximum RMS radius of the diffuse spot is 3.885 μm across the entire field of view.

[0133] like Figure 9 The figure shows the dot plot of the short-wave dual-channel module of the optical system of the present invention in each field of view. The maximum RMS radius of the speckle in the entire field of view is 9.564 μm.

[0134] like Figure 10 The figure shows the dot plot of the wave-wave dual-channel module in the optical system of the present invention in each field of view. The maximum RMS radius of the speckle is 19.940 μm in the entire field of view.

[0135] like Figure 11 The image shows the grid distortion diagram of the visible dual-channel module of the optical system of the present invention in each field of view, with the maximum distortion being -0.0908%.

[0136] like Figure 12 The image shows the grid distortion diagram of the short-wave dual-channel module of the optical system of the present invention in each field of view, with the maximum distortion being -0.0971%.

[0137] like Figure 13 The image shows the grid distortion diagram of the wave-wave dual-channel module in the optical system of this invention in each field of view, with the maximum distortion being -0.0784%.

[0138] This invention provides a system with integrated detection and imaging capabilities across multiple broad spectral bands. It can achieve polarization detection imaging across six channels in the 0.4μm–0.9μm, 1.1μm–1.7μm, and 3.7μm–5μm spectral ranges. This solves the problem of real-time multi-spectral, multi-channel fusion imaging in current space target detection cameras, meeting the polarization detection imaging requirements of space target detection cameras for small-sized space targets across multiple broad spectral ranges. The system also exhibits excellent imaging quality, addressing the issues of low energy concentration and large distortion in the optical systems of current space target detection cameras, thus satisfying the high-precision acquisition and photometric detection capabilities of space target detection cameras for small-sized targets.

[0139] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A multi-spectral band common-path multi-channel polarization detection optical system, characterized in that... include: The system includes a main optical path shared module, a dichroic filter module, a visible spectrum dual-channel module, a shortwave spectrum dual-channel module, and a midwave spectrum dual-channel module; the system's light incident direction is defined as the front of the system; specifically: The main optical path shared module is placed at the very front of the system to achieve multi-spectral integration and coordination of the optical system; the optical axis of the main optical path shared module is referred to as the main optical axis. The color separation module is located at the rear end of the main optical path shared module and on the main optical axis. After the light passing through the main optical path shared module is filtered by spectrum, it is sent to the visible spectrum dual-channel module, the short-wave spectrum dual-channel module, and the mid-wave spectrum dual-channel module for further filtering. The optical axes of the visible spectrum dual-channel module, the shortwave spectrum dual-channel module, and the midwave spectrum dual-channel module are all perpendicular to the main optical axis. They receive light from the corresponding spectral bands selected by the dichroic filter module and perform imaging of the corresponding spectral bands.

2. The multi-spectral band common-path multi-channel polarization detection optical system according to claim 1, characterized in that: The main optical path shared module includes: primary mirror and secondary mirror; The primary mirror is located between the secondary mirror and the dichroic filter module; the surfaces of the secondary mirror and the primary mirror that face each other are reflective surfaces, and a through hole is provided in the center of the primary mirror. When the primary mirror reflects the incident light to the secondary mirror, the secondary mirror reflects the light and it passes through the through hole of the primary mirror to reach the dichroic filter module. The color separation module includes: a first color separation and a second color separation arranged from front to back.

3. The multi-spectral band common-path multi-channel polarization detection optical system according to claim 2, characterized in that: The visible spectrum dual-channel module includes: a visible polarizing beam splitter, two identical first visible light lenses, two identical second visible light lenses, and two identical third visible light lenses; specifically: Light rays pass through the primary mirror and secondary mirror and are incident on the first dichroic filter. The visible light is reflected by the front surface of the first dichroic filter. The visible light reflected by the first dichroic filter is split into two paths by a visible polarizing beam splitter. The two beams are perpendicular to each other, and the lens arrangement in the two paths is exactly the same. Each beam passes through the first visible light lens, the second visible light lens, the third visible light lens and the cover glass in sequence and then converges on the image plane.

4. The multi-spectral band common-path multi-channel polarization detection optical system according to claim 2, characterized in that: The short-wavelength dual-channel module includes: a short-wavelength polarizing beam splitter, two identical short-wavelength first lenses, two identical short-wavelength second lenses, two identical short-wavelength third lenses, and two identical short-wavelength fourth lenses; specifically: Light passes through the primary mirror, secondary mirror, and first dichroic filter before entering the second dichroic filter. The short-wavelength light is reflected by the front surface of the second dichroic filter to the short-wave polarizing beam splitter. The short-wave polarizing beam splitter splits the light into two beams that are perpendicular to each other. The lenses in the two beams are arranged in the same way. Each beam passes through the first short-wavelength lens, the second short-wavelength lens, the third short-wavelength lens, the fourth short-wavelength lens, and the cover glass in sequence before converging on the image plane.

5. The multi-spectral band common-path multi-channel polarization detection optical system according to claim 1, characterized in that: The mid-wave spectrum dual-channel module includes: a first folding mirror, a second folding mirror, a third folding mirror, a mid-wave first lens, a mid-wave polarizing beam splitter, two identical mid-wave second lenses, two identical mid-wave third lenses, two identical mid-wave fourth lenses, and two identical mid-wave fifth lenses; specifically: After light passes through the primary mirror, secondary mirror, first dichroic filter, and second dichroic filter, it is reflected by the first folding mirror to the second folding mirror, then by the second folding mirror to the third folding mirror, and finally by the third folding mirror to the first mid-wave lens. After being transmitted through the first mid-wave lens, it is incident on the mid-wave polarizing beam splitter to achieve two beam splits. The two beam splits are perpendicular to each other, and the lenses in the two beam splits are identical. Each beam splits sequentially through the second mid-wave lens, the third mid-wave lens, the fourth mid-wave lens, the fifth mid-wave lens, the cover glass, and the filter before converging on the image plane.

6. The multi-spectral band common-path multi-channel polarization detection optical system according to claim 1, characterized in that: The operating spectral band of the optical system is: The visible spectrum ranges from 0.4 μm to 0.9 μm, the shortwave spectrum ranges from 1.1 μm to 1.7 μm, and the midwave spectrum ranges from 3.7 μm to 5 μm.

7. The multi-spectral band common-path multi-channel polarization detection optical system according to claim 2, characterized in that: The reflecting surfaces of the primary mirror and the secondary mirror are both quadratic curved surfaces; the first dichroic filter and the second dichroic filter are both planar. Both the primary and secondary mirrors have reflective coatings on their reflective surfaces, with a reflectivity greater than 0.97 in the 0.4μm to 5μm spectral range. The front surface of the first dichroic filter is a reflective surface with a reflection spectrum of 0.4 μm to 0.9 μm, and the transmission spectrum of the rear surface of the first dichroic filter is 1.1 μm to 1.7 μm and 3.7 μm to 5 μm. The front surface of the second dichroic filter is a reflective surface with a reflection spectrum of 1.1 μm to 1.7 μm, and the rear surface of the second dichroic filter 2 has a transmission spectrum of 3.7 μm to 5 μm. The primary mirror material is SiC; the secondary mirror material is microcrystalline. The materials for the first and second color separations are ZNSE.

8. The multi-spectral band common-path multi-channel polarization detection optical system according to claim 3, characterized in that: In the visible spectrum dual-channel module: The first visible light lens, the second visible light lens, and the third visible light lens are all spherical. The first visible light lens, the second visible light lens, and the third visible light lens are coated with anti-reflection coatings, and the transmittance in the 0.4μm to 0.9μm spectral range is greater than 0.

99. The visible polarizing beam splitter has a polarizing film coated on its inclined surface, with a polarization degree ≥ 500:1; The material of the first visible light lens is N-FK58, the material of the second visible light lens is N-KZFS2, and the material of the third visible light lens is N-FK58; It can be seen that the material of the polarizing beam splitter is H-ZF3.

9. The multi-spectral band common-path multi-channel polarization detection optical system according to claim 4, characterized in that: In the shortwave dual-channel module: The front surface of the first shortwave lens is cylindrical, and the rear surface is planar; the second, third, and fourth shortwave dual-channel lenses are all spherical. The first short-wavelength lens, the second short-wavelength lens, the third short-wavelength lens, and the fourth short-wavelength lens are coated with anti-reflective coatings, and the transmittance is greater than 0.99 in the 1.1μm to 1.7μm spectral range. The inclined surface of the short-wave polarizing beam splitter is coated with a polarizing film, with a polarization degree ≥500:1; The first shortwave lens is made of SILICA, the second shortwave lens is made of N-LASF31A, the third shortwave lens is made of N-SF66, and the fourth shortwave lens is made of N-LASF31A. The material of the short-wave polarization beam splitter is H-ZF3.

10. A multi-spectral band common-path multi-channel polarization detection optical system according to claim 5, characterized in that: In the mid-wave spectrum dual-channel module: The first, second, third, fourth, and fifth lenses of the medium-wave wave are all spherical; the first, second, and third folding mirrors of the medium-wave dual-channel are all planar. The first, second, third, fourth, and fifth medium-wave lenses are coated with anti-reflective coatings, and the transmittance is greater than 0.99 in the 3.7μm to 5μm spectral range. The first, second, and third refracting mirrors are coated with reflective films, and their reflectivity is greater than 0.97 in the 3.7μm to 5μm spectral range. Mid-wave polarizing beam splitter with a polarizing film coated on the inclined surface, polarization degree ≥300:1 The first, second, and third folding mirrors are made of microcrystalline materials. The medium-wave first lens is made of GERMANIUM, the medium-wave second lens is made of SILICON, the medium-wave third lens is made of ZNSE, the medium-wave fourth lens is made of ZNSE, and the medium-wave fifth lens is made of SILICON. The medium-wave polarization beam splitter is made of SILICON.

Images