CN104536124A

CN104536124A - Plan apochromatic measuring microobjective with 2* overlength working distance and without CaF2

Info

Publication number: CN104536124A
Application number: CN201410852525.8A
Authority: CN
Inventors: 萧泽新
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: 2015-04-22
Anticipated expiration: 2034-12-31
Also published as: CN104536124B

Abstract

The invention discloses a plan apochromatic measuring microobjective with a 2* overlength working distance and without CaF2. The plan apochromatic measuring microobjective is composed of five lenses including the convex lenses and the concave lenses, the convex lenses and the concave lenses are made of optical glass materials without the CaF2 and are divided into three optical groups, and all the lenses are coaxial with the center of an object plane and sequentially comprise the first convex lens, the second concave lens, the third convex lens, the fourth concave lens, the fifth concave lens and the object plane from left to right. The object plane is imaged at an infinite distance through an optical system. The plan apochromatic measuring microobjective has the advantages that low power measuring microobjective without the CaF2 achieves the plan apochromatic effect; the oversized field of view and the overlength working distance are achieved; the overlength parfocal effect is achieved; the microobjective is made of all-photonic glass, and thus the cost performance is high.

Description

A kind of without CaF 22 × SLWD flat field apochromatism metering microcobjective

Technical field

The present invention relates to microcobjective, specifically a kind of without CaF ₂2 × SLWD flat field apochromatism metering microcobjective.

Background technology

Microcobjective is the most important parts of measuring microscope, and the height of its image quality directly affects the performance of measuring microscope.Flat field apochromatic micro objective is as best in quality, that class is the highest microcobjective.For to correct elementary axial chromatic aberration and second order spectrum simultaneously in object lens, traditional way in part positive lens, introduces optical crystal, as calcium fluoride CaF ₂deng as manufactured materials, but this special optical material yield is few, more crisp, physicochemical property is unstable, and large-sized material is more difficult to obtain.In recent years, someone uses special glass (as TF ₃) substitute or Some substitute CaF ₂manufacture and design flat field apochromatic objective, show superiority reducing costs and improve in manufacturability, caused inventor and this work is in depth studied further, finally design a kind of without CaF ₂2 × SLWD flat field apochromatism metering microcobjective.It is worthy of note, along with modern science and technology progress, measuring technology and instrument industrial circle application in increasingly extensive, require that the operating distance measuring microcobjective is more and more longer, the microcobjective structure of metering becomes increasingly complex, three rich companies of international famous brand Japan go with the tide of historical development, the object lens of the release overlength that takes the lead in parfocalization distance=95mm; The microcobjective of 95mm parfocalization distance has become so far overlength parfocalization distance new standard in the world.This defines and makes metering microcobjective achieve SLWD (as three rich 100 ×/0.7, W.D=6mm).These object lens are exactly that inventor is based on the low power objective of 95mm parfocalization apart from the complete metering microcobjective of SLWD flat field apochromatism of research and development.

Summary of the invention

The object of the present invention is to provide one both ultra-large vision field, overlength parfocalization distances, again cost performance high without CaF ₂2 × SLWD flat field apochromatism metering microcobjective.

The present invention is according to combined light focal power formula φ=φ ₁+ φ ₂-d φ ₁φ ₂(φ ₁φ ₂be respectively the focal power of light group 1,2, d is the distance between the second interarea of light group 1 and the first interarea of light group 2) the positive and negative group of long reach microcobjective being far separated " counter take the photograph far away " type can be determined, structural shape selects the camera lens of close structural as initial configuration thus, then by convergent-divergent, iteration optimization, finally obtain picture element excellent without CaF ₂2 × SLWD flat field apochromatism metering microcobjective.

The present invention is without CaF ₂2 × SLWD flat field apochromatism metering microcobjective, by 5 not containing CaF ₂the convex lens made of optical glass material and concavees lens be divided into forward and backward 2 light groups and form, and each lens and object plane central coaxial, put in order as first convex lens, second concave lens, the 3rd concavees lens, the 4th convex lens, the 5th concave lens, object plane from left to right; Object plane by optical system imaging in unlimited distance.

In described 2 light groups, the 1st light group near image planes is the two gummed groups be made up of first convex lens and second concave lens, add the 3rd concavees lens of contiguity, the 2nd light group near object plane is the two gummed groups be made up of the 4th convex lens and the 5th concavees lens.

1st light group of the close image planes in described 2 light groups is far separated with near between the 2nd light group of object plane.

Distance from the summit of the 5th concavees lens to object plane is operating distance W.D.

Operating distance W.D=30.93mm of the present invention;

Enlargement ratio β=2 × (coordinating with f '=200mm tube lens);

Numerical aperture >=0.055; Aperture angle > 3.45 ° (image space φ 24mm);

Focal distance f '=100mm;

The evaluation of these object lens main performance is as follows: 1. show through geometrical aberration evaluation and PTZ3 tables of data contrast test, reflect that F, c light is brought at 0.707 ω intuitively to intersect at a point, value of chromatism PAC=0.00033, secondary light spectrum SAC=0.003521, being about and not correcting 7% of SAC ≈ 0.05mm, is correct reasonable; The spherochromatism of three kinds of wavelength is also less.2. flat field effect also quite satisfaction a: thatch ten thousand curvature of field (PTZ3)=-0.002504.3. visual limiting resolution N _max=153lp/mm, from Fig. 4, the MTF curve of this microcobjective and MTF data value, full filed MTF>=0.11, presses close to perfect optical system MTF line substantially.4. energy shared by full filed bright spot of view-field center is up to 97%.Its advantage is:

Not containing CaF ₂low power metering microcobjective, reaches flat field apochromatism effect;

Ultra-large vision field, SLWD;

Cost performance is high;

Overlength parfocalization distance.

Accompanying drawing explanation

Fig. 1 is microcobjective structural representation of the present invention;

Fig. 2 is the geometrical aberration evaluation map of microcobjective of the present invention;

Fig. 3 is PTZ3 tables of data of the present invention;

Fig. 4 is optical transfer function MTF curve map of the present invention, table;

Fig. 5 is encircled energy distribution plan of the present invention

Fig. 6 Japan three rich parfocalization distance=95mm complete metering microcobjective parameter list.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further elaborated.

As shown in Figure 1, the present invention is without CaF ₂2 × SLWD flat field apochromatism metering microcobjective, by 5 not containing CaF ₂the convex lens made of optical glass material and concavees lens be divided into 3 groups of formations, and each lens and object plane central coaxial, scheduling is from left to right: first convex lens 1, second concave lens 2, the 3rd concavees lens 3, the 4th convex lens 4, the 5th concave lens 5, object plane 6; Object plane 6 by optical system imaging in unlimited distance.

In described 2 light groups: the 1st light group is the two gummed groups be made up of first convex lens and second concave lens, add the 3rd concavees lens of contiguity; 2nd light group is the two gummed groups, the 1st light group and the 2nd light group that are made up of the 4th convex lens and the 5th concavees lens separation far away, its spacing is 31.8mm.

Fig. 2 is the geometrical aberration evaluation map of this microcobjective; Fig. 3 is the PTZ3 tables of data of these object lens; From Fig. 2 and Fig. 3, represent that F, c bring at 0.707 ω and intersect, value of chromatism PAC=0.000333; Second order spectrum SAC=0.003521 is smaller (being about 7% of non-corrected value), and 3 chromatic curve spacing are little also reflects this point.Flat field effect is quite satisfaction also: a thatch ten thousand curvature of field (PTZ3)=-0.002504.From Fig. 4,35, visual field MTF curves press close to the MTF of perfect optical system, and visual limiting resolution N _maxfull filed MTF>=0.11 during=153lp/mm.From Fig. 5, energy shared by full filed bright spot of view-field center is (when >=83%, then wave aberration≤λ/16) up to 97%, and the object lens picture element of visible the design is satisfactory.

Compared with Japan's three rich 2 × object lens in Fig. 5, the object lens of the design are except operating distance is slightly shorter than three high yield product, and all the other performances and three product of getting bumper crops maintain an equal level.

Claims

1. one kind without CaF ₂2 × SLWD flat field apochromatism metering microcobjective, comprises lens, it is characterized in that: by 5 not containing CaF ₂the convex lens made of optical glass material and concavees lens be divided into forward and backward 2 light groups and form, and each lens and object plane central coaxial, put in order as first convex lens, second concave lens, the 3rd convex lens, the 4th concavees lens, the 5th concave lens, object plane from left to right; Object plane by optical system imaging in unlimited distance.

2. microcobjective according to claim 1, it is characterized in that: in described 2 light groups, the 1st light group near image planes is the two gummed groups be made up of first convex lens and second concave lens, add the 3rd concavees lens of contiguity, the 2nd light group near object plane is the two gummed groups be made up of the 4th convex lens and the 5th concavees lens.

3. microcobjective according to claim 2, is characterized in that: the 1st light group of the close image planes in described 2 light groups is far separated with near between the 2nd light group of object plane.

4. microcobjective according to claim 1, is characterized in that: the long reach W.D=30.93mm of these object lens, enlargement ratio β=2 × and, focal distance f ' and=100mm, numerical aperture NA=0.055, aperture angle ω=3.45 °; Parfocalization distance=95mm.