Background technology:
In space science and Earth Information Science field; Ultra-optical spectrum imaging system can obtain the space geometry information and the spectral information of observed object simultaneously; It is important target signature obtaining means; Have very application prospects at aspects such as national economy and scientific researches, the size along with current infrared focus plane increases the big visual field of active demand, highly sensitive infrared spectral coverage hyperspectral imager simultaneously.
The optical system of composing the short-wave infrared imaging spectrometer with the comparatively approaching ultraphotic of the present invention is people's design " a kind of optical system of spectroscopic imaging spectrometer of prism " (number of patent applications: 200910197304.0) such as the Wang Xin of Shanghai Inst. of Technical Physics, Chinese Academy of Sciences; As shown in Figure 1, comprise slit 1, collimation off axis reflector mirror 2; Dispersing prism 3; Imaging off axis reflector mirror 4 is from axle spherical correction lens 5, image planes 6.The distance of collimation off axis reflector mirror 2 and slit 1 is d1; Collimation off axis reflector mirror 2 is d2 with the spacing distance of imaging off axis reflector mirror 4; Dispersing prism 3 is positioned on the reflected light path of collimation off axis reflector mirror 2 and the spacing distance of collimation off axis reflector mirror 2 is d3-d2, and imaging off axis reflector mirror 4 is positioned on the reflected light path of dispersing prism 3; With the spacing distance of dispersing prism 3 be d3; Be positioned on the reflected light path of imaging off axis reflector mirror 4 from axle spherical correction lens 5 and the spacing distance of imaging off axis reflector mirror 4 is d4, image planes 6 and be d5 from the spacing distance of axle spherical correction lens 5.Collimation off axis reflector mirror 2 is respectively secondary hyperboloidal mirror and ellipsoidal mirror with imaging off axis reflector mirror 4, and their focal length distributes the focal length requirement of considering total system, and respectively with beam collimation and convergence; The angle design of two faces of dispersing prism 3 should satisfy the spectral resolution requirement of system, also will satisfy the crooked and non-linear requirement of spectrum of spectrum of system simultaneously; Be used for the aberration of the outer big visual-field beam of axis calibration from the design of axle spherical correction lens 5; Reduce the spectrum bending; Because this system design does not contain pre-objective, aberration correction is limited in one's ability, and field angle only can reach 1.43 degree; Can't satisfy big visual field demands of applications, and not see ultra wide-angle short-wave infrared ultra-optical spectrum imaging system design report both at home and abroad at present as yet.
The pre-objective of existing ultra-optical spectrum imaging system mostly separately designs with spectrum imaging system; Limited in one's ability on the correction overall aberration; And in the design of short-wave infrared imaging system, generally selected the infrared band material for use; Although the infrared band material can effectively promote the energy transmitance at infrared band; But the infrared band drawing abillity can't be compared with the ordinary optical glass material, be difficult to design the high-quality optical system of the low distortion in big visual field, and the infra-red material price is very high.
Summary of the invention:
For overcoming less, the more high defective of cost of design field angle that prior art exists, the objective of the invention is to: obtain ultra wide-angle short-wave infrared Hyper spectral Imaging optical system, increase the terrain object spectral information that can obtain to greatest extent.
The technical matters that the present invention will solve is: provide a kind of ultra wide-angle short-wave infrared to push away the optical system of sweeping hyperspectral imager.The technical scheme of technical solution problem is as shown in Figure 2; Be to be made up of pre-objective group and light spectrum image-forming reflector group, wherein the pre-objective group comprises first lens 7, second lens 8, the 3rd lens 9, the 4th lens 10, the 5th lens 11, the 6th lens 12, aperture diaphragm 13, the 7th lens 14, the 8th lens 15, the 9th lens 16, the tenth lens 17; The light spectrum image-forming reflector group comprises entrance slit 18, principal reflection mirror 19, convex grating catoptron 20, the 3rd catoptron 21, line array CCD 22.
In the pre-objective group; On same optical axis, be arranged in order first lens 7, second lens 8, the 3rd lens 9, the 4th lens 10, the 5th lens 11, the 6th lens 12, aperture diaphragm 13, the 7th lens 14, the 8th lens 15, the 9th lens 16, the tenth lens 17 from left to right; Wherein the spacing distance between first lens 7 and second lens 8 is d6; Spacing distance between second lens 8 and the 3rd lens 9 is d7, and the spacing distance between the 3rd lens 9 and the 4th lens 10 is d8, and the spacing distance between the 4th lens 10 and the 5th lens 11 is d9; Spacing distance between the 5th lens 11 and the 6th lens 12 is d10; Spacing distance between the 6th lens 12 and the aperture diaphragm 13 is d11, the 7th lens 14 0.1mm place behind aperture diaphragm, the back surface of the 7th lens 14 and the front surface of the 8th lens 15 formation cemented surface glued together; Spacing distance between the 8th lens 15 and the 9th lens 16 is d12, and the spacing distance between the 9th lens 16 and the tenth lens 17 is d13; Spectral reflectance mirror group is concentric three catoptric imaging optics systems; In spectral reflectance mirror group; The tenth lens 17 in principal reflection mirror 19 and the pre-objective group are on same optical axis, and in the light path that the tenth lens 17 and principal reflection mirror 19 form, the spacing distance in the back focal plane place of pre-objective group placement entrance slit 18 principal reflection mirrors 19 and pre-objective group between the tenth lens 17 is d14; Convex grating catoptron 20 is on the reflected light path of principal reflection mirror 19; With the spacing distance of principal reflection mirror 19 be d15, the 3rd catoptron 21 on the reflected light path of convex grating catoptron 20, with the spacing distance of convex grating catoptron 20 be d16; Line array CCD 22 on the reflected light path of the 3rd catoptron 21, with the spacing distance of the 3rd catoptron 21 be d17.
Principle of work of the present invention is: when being used for push-scanning image; Ground object target information from different visual fields gets into the pre-objective group; Through first lens 7, second lens 8, the 3rd lens 9, the 4th lens 10, the 5th lens 11, the 6th lens 12, aperture diaphragm 13, the 7th lens 14, the 8th lens 15, the 9th lens 16, the tenth lens 17, the place forms specific bar shaped visual field in pre-objective group back focus successively.Distance between each lens is through using optical design software optimization; Taken into full account the system aberration correction; Selected for use several kinds the glass (for example ZBAF4 and ZF12) of good transmitance to be arranged in the pre-objective group, promptly satisfied transmissivity and require to be more prone to simultaneously correcting chromatic aberration, the curvature of field at the short-wave infrared spectral coverage.
Different field rays through entrance slit 18 incide on the convex grating catoptron 20 through principal reflection mirror 19 collimations; Diffraction takes place on convex grating catoptron 20 surfaces in the light of incident; Pass through the 3rd catoptron 21 convergence reflexs to line array CCD 22 through each band of light of optical grating diffraction, realize the different spectral coverage imaging.Spacing distance between principal reflection mirror 18, convex grating catoptron 19, the 3rd catoptron 20, the line array CCD 21 satisfies the demand of system's focusing through optical design software optimization.In the light spectrum image-forming reflector group, adopt new-type concentric three catoptric imagings of convex surface reflection grating (Offner) structure; Wherein convex surface is set to the optical grating reflection mirror; And spectral reflectance mirror group adopts and the method for pre-objective group composite design; Because there is certain heart characteristic non-far away in the pre-objective group, so the logical light size of three catoptrons slightly changes in the light spectrum image-forming reflector group.For example convex grating catoptron 20 is an aperture diaphragm in the independent design of spectrum imaging system, should be circle, but after system in combination, becomes Long Circle, and spectrum imaging system mirror aperture shape is as shown in Figure 3.
Good effect of the present invention is:
Realize ultraphotic spectrum, big visual field at the short-wave infrared wave band, its field angle reaches 90 °, push-scanning image, and movement-less part, encircled energy is high.Spectrum imaging system adopts new-type concentric three catoptric imagings of convex surface reflection grating (Offner) structure, and system is compact more, reduced system weight, and chromatic variation of distortion is little, and no spectral line is crooked.
Adopt pre-objective and spectrum imaging system composite design, make this optical system in 1 μ m~2.5 mu m wavebands, have favorable imaging quality, each visual field modulation transfer function (MTF) of system is all greater than 0.4.
Native system has adopted the ordinary optical glass material to proofread and correct the short-wave infrared aberration in the pre-objective group in a large number, when obtaining good picture element, has greatly reduced design cost.
Embodiment:
The present invention implements according to optical system structure shown in Figure 2, in order to increase the energy transmitance of optical system, the glass of preposition image-forming objective lens group is selected.In simple glass, there is the glass of several trades mark to have good transmitance, for example ZBAF4 and ZF12 at the short-wave infrared spectral coverage.Therefore, the present invention has adopted these two kinds of simple glass materials to come correcting chromatic aberration, the curvature of field on the basis of satisfying the transmissivity requirement in a large number.Wherein first lens 7, the 3rd lens 9, the 6th lens 12, the 9th lens 16, the tenth lens 17 are the fused quartz material; Second lens 8, the 4th lens 10, the 8th lens 15 flint optical glass material ZF12 that attaches most importance to; The 5th lens 11 barium flint optical glass material ZBAF4 that attaches most importance to, the 7th lens 14 are the calcium fluoride optical crystal material.
The design of Optical System index is spectral range 1 μ m~2.5 μ m, 256 spectrum channels, and the concrete design parameter index of pre-objective group is following:
Focal length: 15mm;
Relative aperture: 1/4.5;
Field angle: 2 ω=90 °;
Spectral range: 1000nm~2500nm;
Profile: Ф 53mm * 150mm;
The concrete design parameter index of spectrum imaging system is following:
Operation wavelength: 1000nm~2500nm;
Slit length: 30.12mm;
Slit image chromatic dispersion width: 7.68mm;
Chromatic variation of distortion: 0.35 μ m;
Spectral line is crooked: 0.22 μ m;
Grating frequency: 72 lines/mm;
Realize above-mentioned two groups of optical system parameter indexs, the optical element technology in pre-objective group and the spectral reflectance mirror group requires to need to carry out by the technical data in the form shown in Figure 4.