CN104570310A

CN104570310A - Flat-field apochromatic metallographic microscope objective with magnification power being 40 and without CaF2

Info

Publication number: CN104570310A
Application number: CN201410848740.0A
Authority: CN
Inventors: 萧泽新; 高兴宇; 肖华鹏
Original assignee: Guilin University of Electronic Technology
Current assignee: Guilin University of Electronic Technology
Priority date: 2014-12-31
Filing date: 2014-12-31
Publication date: 2015-04-29

Abstract

The invention discloses a flat-field apochromatic metallographic microscope objective with magnification power being 40 and without CaF2. The metallographic microscope objective is composed of 8 lenses divided into 3 groups. The work distance W.D. of the microscope objective is 0.15 mm, the magnification power is 40, the numerical aperture is larger than 0.7, the aperture angle omega is larger than 2 degrees, and the effective focal length f' is 6.27 mm. The metallographic microscope objective can be widely applied to various metallographic microscope devices, and has the advantages that the metallographic microscope objective without the CaF2 achieves the flat-field apochromatic effect, a high performance cost ratio is achieved, and the structure is simple.

Description

A kind of without CaF 240 × excluding plan apochromatic metallographic microobjective

Technical field

The present invention relates to microcobjective, particularly a kind of without CaF ₂40 × excluding plan apochromatic metallographic microobjective.

Background technology

Microcobjective is the important composition parts of metaloscope, and the height of its image quality, directly affects the performance of metaloscope.Flat field apochromatic micro objective is the microcobjective that picture element is best, class is the highest.Be correct axial chromatic aberration and second order spectrum in object lens, conventional way in part positive lens, introduces optical crystal, as calcium fluoride CaF simultaneously ₂deng as manufactured materials, but special optical material is few, more crisp, and physicochemical property is unstable, and large-sized material is more difficult to obtain." the practical optics technical manual " (2006 of king Zhijiang River chief editor, Beijing: China Machine Press) in mention a kind of domestic similar 40 × flat field achromatic micro objective, be made up of 7 lens, wherein have 2 FK system glass employing low-refraction, cost is higher.

In recent years, someone uses special glass (as TF ₃) partly substitute CaF ₂manufacture and design flat field apochromatic objective, demonstrate superiority reducing costs and improve in manufacturability, caused inventor to CaF ₂the further investigation of apochromatism imaging mechanism, adds the technical progress of domestic glass, impels us to design without CaF ₂flat field apochromatic micro objective.

Summary of the invention

It is simple without CaF that the object of the invention is to provide a kind of high performance-price ratio, structure ₂40 × flat field apochromatic micro objective, can correct axial chromatic aberration and second order spectrum simultaneously.

The technical scheme realizing the object of the invention is:

A kind of without CaF ₂40 × excluding plan apochromatic metallographic microobjective, by 8 not containing CaF ₂the convex lens made of optical glass and concavees lens be divided into 3 light groups and form, each lens and object plane central coaxial, order is followed successively by infinity image planes, first convex lens, second concave lens, the 3rd concavees lens, the 4th convex lens, the 5th concavees lens, the 6th convex lens, the 7th convex lens, the 8th convex lens from left to right, object plane, distance between 1st to convex lens is infinity, from the 8th convex lens summit to the distance of object plane be W.D.

In described 3 light groups, 1st light group is made up of first convex lens and second concavees lens interval, the three gummed groups that 2nd light group is made up of the 3rd concavees lens, the 4th convex lens, the 5th concave lens and the 6th convex lens are formed, 3rd light group is the 7th convex lens and the 8th convex lens composition, the 8th convex lens wherein near object plane are aplanatic thick meniscus lens, and described second concave lens are positive meniscus shaped lens.

The operating distance W.D.=0.15mm of described lens, enlargement ratio is 40 × (coordinating with f '=250mm tube lens), numerical aperture > 0.7, aperture angle ω > 2 °, focal distance f '=6.27mm, parfocalization distance=45mm.

Advantage of the present invention is: 1, not containing CaF2 metallography microscope object lens, reach flat field apochromatism effect; 2, full photonic glass is formed, and cost performance is high; 3, lens number is few, and structure is simple.

Accompanying drawing explanation

Fig. 1 microcobjective structure;

The geometrical aberration evaluation map of Fig. 2 microcobjective;

The point spread function figure of Fig. 3 microcobjective;

The mtf value of each visual field under the MTF curve of Fig. 4 microcobjective and limiting resolution;

The aberration data of Fig. 5 microcobjective;

The flat-field objective structural drawing of the identical enlargement factor of Fig. 6 Leca;

The flat field apochromatic objective structural drawing of the identical enlargement factor of Fig. 7 USSR (Union of Soviet Socialist Republics);

Domestic like product structural drawing (a) of Fig. 8 and aberration curve figure (b).

In figure: 1, infinity image planes 2, positive lens 3, positive lens 4, negative lens 5, positive lens 6, negative lens 7, positive lens 8, positive lens 9, positive lens 10, object plane.

Embodiment

Below in conjunction with the drawings and specific embodiments, the invention will be further elaborated.

With reference to Fig. 1, the present invention is a kind of without CaF ₂40 × excluding plan apochromatic metallographic microobjective, by 8 not containing CaF ₂the convex lens made of optical glass and concavees lens be divided into 3 light groups and form, each lens and object plane central coaxial, order is followed successively by infinity image planes 1, first convex lens 2, second concave lens 3, the 3rd concavees lens 4, the 4th convex lens 5, the 5th concavees lens 6, the 6th convex lens 7, the 7th convex lens 8, the 8th convex lens 9 from left to right, object plane 10, distance between 1st to convex lens is infinity, from the 8th convex lens 9 summit to the distance of object plane be W.D.

In described 3 light groups, 1st light group is be made up of the first convex lens 2 and second concave lens 3 with certain intervals, its spacing is 1.57mm, the three gummed groups that 2nd light group is made up of the 3rd concavees lens 4, the 4th convex lens 5, the 5th concave lens 6 and the 6th convex lens 7 are formed, the spacing of three gummed groups and the 6th convex lens is 0.2mm, 3rd light group is that the 7th convex lens 8 and the 8th convex lens 9 form, and its spacing is 0.1mm; The spacing of the 1st light group and the 2nd light group is 5.23mm, and the spacing of the 2nd light group and the 3rd light group is 0.1mm; The 8th convex lens 9 wherein near object plane are aplanatic thick meniscus lens, and described second concave lens 3 are positive meniscus shaped lens.

Use OSLO optical design CAD software, optimize " r, d, n " (r is the radius of lens, and d is the thickness of lens, and n is the refractive index of lens) textural element, have devised without CaF ₂40 × excluding plan apochromatic metallographic microobjective.

Operating distance W.D.=0.15mm; Enlargement ratio 40 ×; Numerical aperture 0.718; Aperture angle 2.06 °; Focal distance f '=6.27mm.

The objective lens design Aberration Analysis that the present invention provides is shown in accompanying drawing 2, accompanying drawing 5 is PTZ3 tables of data of these object lens, from accompanying drawing 2 and accompanying drawing 5, can reflect that d, F, c light almost intersects at a point on tape intuitively, the spherochromatism of three kinds of wavelength is also less, flat field effect is quite satisfaction also, a thatch ten thousand curvature of field (PTZ3)=-0.000907.Visible is a quite outstanding optical texture.Carried out contrasting rear (see accompanying drawing 6, accompanying drawing 7) with the product of multiplying power with German Lay thatch, USSR (Union of Soviet Socialist Republics), it has goodish cost performance.Germany's Lay thatch object lens form by 5, are flat-field achromatic objective lens; USSR (Union of Soviet Socialist Republics) flat field apochromatic objective forms by 8, and wherein contains CaF2.The numerical aperture of these two object lens is 0.65, is all less than the present invention.

Claims

1. one kind without CaF ₂40 × excluding plan apochromatic metallographic microobjective, comprises lens, it is characterized in that: by 8 not containing CaF ₂the convex lens made of optical glass and concavees lens be divided into 3 light groups and form, each lens and object plane central coaxial, order is followed successively by infinity image planes, first convex lens, second concave lens, the 3rd concavees lens, the 4th convex lens, the 5th concavees lens, the 6th convex lens, the 7th convex lens, the 8th convex lens from left to right, object plane, distance between 1st to convex lens is infinity, from the 8th convex lens summit to the distance of object plane be W.D.

2. microcobjective according to claim 1, it is characterized in that: in described 3 light groups, 1st light group is made up of first convex lens and second concavees lens interval, the three gummed groups that 2nd light group is made up of the 3rd concavees lens, the 4th convex lens, the 5th concave lens and the 6th convex lens are formed, 3rd light group is the 7th convex lens and the 8th convex lens composition, the 8th convex lens wherein near object plane are aplanatic thick meniscus lens, and described second concave lens are positive meniscus shaped lens.

3. microcobjective according to claim 1, it is characterized in that: the operating distance W.D.=0.15mm of described lens, enlargement ratio is 40 × (coordinating with f '=250mm tube lens), numerical aperture > 0.7, aperture angle ω > 2 °, focal distance f '=6.27mm, parfocalization distance=45mm.