A kind of two heart Kohler illumination light path far away
Technical field
The present invention relates to a kind of novel illumination light path, particularly a kind of two heart Kohler illumination light path far away.
Background technology
Illumination path is the important composition parts of optical system, and the height of its light source quality directly affects the performance of optical system.Common low side optical system is utilized natural light or bulb direct illumination, if will satisfy the requirement of numerical aperture and illumination uniformity, then will adopt condenser to strengthen design.
At present, illuminator commonly used has critical illumination, oblique illumination, reflective illumination and Kohler illumination.
Critical illumination: refer to a kind of means of illumination of the illuminated system imaging of light source on object plane, the characteristics of this illumination are that light source is through being imaged on behind the condenser on the tested object, field stop is at light source position, aperture diaphragm is located near optically focused picture frame or its, thereby this illumination has high-high brightness in the object plane field range, and do not have veiling glare.But the filament picture of light source and the planes overlapping of tested object present unevenness with regard to the illumination that causes tested object like this, and be then bright in the part that filament is arranged, part without filament is then dim, not only affect the quality of imaging, more be not suitable for photomicrograph, this is the major defect of critical illumination.
Oblique illumination: the axis of this illuminating bundle and microscopical optical axis cast oblique rays on object but have a certain degree with optical axis shape not on same straight line, therefore become oblique illumination.
Reflective illumination: the light beam of this illumination is mapped on the tested object after by object lens from the top of object, and object lens play a part again condenser like this.This illumination is only applicable to nontransparent object, such as metal, and mineral etc.
Kohler illumination: refer to the method for a kind of illuminated objects of illuminated system imaging on the object lens entrance pupil, this method has overcome the inhomogeneous shortcoming of critical illumination, is the desirable illumination of research in the micro measurement system.This illumination not only observing effect is good, and is successfully to carry out the necessary a kind of illumination of photomicrograph.The filament of light source is behind collecting lens and variable field stop, and for the first time filament looks like to drop on the place, plane of condenser aperture diaphragm, condenser again with this once as forming secondary filament picture at place, back focus plane.Do not have like this formation of filament picture at place, plane, tested object place, do not affect observation.Illumination becomes even in addition.During observation, can change the size of condenser aperture diaphragm, make light source be full of the entrance pupil of different object lens, and make the numerical aperture of condenser and the numerical aperture coupling of object lens.Condenser is imaged on field stop again the place, plane of tested object simultaneously, and the size that changes field stop can be controlled illumination zone.In addition, the hot focus of this illumination is not or not the place, plane of tested object, even long illumination, the also tested object of unlikely damage.Still its eyeglass is more although the Kohler illumination effect is pretty good, and processing is comparatively complicated, installs and place the accuracy requirement height, therefore also has the relatively high problem of cost.
Summary of the invention
The objective of the invention is for the deficiencies in the prior art, provide that a kind of eyeglass number is few, simple in structure, image quality is high, the adjustable two heart Kohler illumination light paths far away of total optical path length.
Two heart Kohler illumination light paths far away refer to aperture diaphragm and are positioned on the object space focal plane of condenser by suitable adjusting, also be positioned at simultaneously picture side's focal plane of collecting lens, consist of picture side's heart far away and the two telecentric beam paths of the object space heart far away, possessed simultaneously picture square object side telecentric beam path characteristics.
Realize that technical scheme of the present invention is:
A kind of two heart Kohler illumination light path far away, comprise light source and lens, 6 lens of this optical routing and light source center arranged in co-axial alignment are divided into collecting lens light group and two light groups of condenser light group form, light path from left to right sorts and is: light source, first meniscus lens, second meniscus lens, the 3rd concavees lens, the 4th convex lens, the 5th convex lens, the 6th concavees lens, be provided with diaphragm between the 4th convex lens and the 5th convex lens, light source projects unlimited distance with light beam after the said lens system.
Described collecting lens light group is comprised of tactic first meniscus lens, second meniscus lens and the 3rd concavees lens of gummed, the 4th convex lens, described condenser light group is comprised of the 5th convex lens and the 6th concavees lens, and the diaphragm face between the two light groups also is the object space focal plane of condenser light group when being the picture side focal plane of collecting lens light group.
Its numerical aperture of objective system that described light path lens consist of is 0.5, and aperture angle is 2.6652 °, and focal length is 43.175mm.
Consisting of between collecting lens light group and the condenser light group is two telecentric systems, and light beam is parallel beam around here, thereby can carry out certain spacing and regulate.
The present invention realizes by following know-why: according to combined light focal power formula
φ=φ 1+
φ 2-
D φ 1 φ 2(
φ 1, φ 2Be respectively light group 1,2 focal powers,
dBe the distance between the first interarea of the second interarea of light group 1 and light group 2) can determine two group Kohler illumination light paths, structural shape selects the illumination path of close structure as initial configuration thus, then by suitable focal length convergent-divergent and the optimal design of aberration, finally obtain the good heart Kohler illumination light path two far away of picture element.
It is initial configuration that the present invention uses existing Kohler illumination, use OSLO optical design CAD software, by the focal length convergent-divergent, the index of refraction in lens) optimize r, d, n(r that number of lenses and lens are set: lens radius, d: lens curvature thickness, n: the textural element such as, make light path reach indices and the requirement of illuminator, and obtain the illuminating effect of high-quality by optical simulation software Lighttools.
Advantage of the present invention is:
1. number of lenses is few, and image quality is high;
2. be convenient to regulate total optical path length, greatly improved the scope of application;
3. cost performance is higher;
4. simple in structure.
Description of drawings
Fig. 1 is the two heart Kohler illumination light channel structure synoptic diagram far away of the present invention;
Fig. 2 is optics point range figure of the present invention and wavelength data figure;
Fig. 3 is optical assessment function MTF figure of the present invention;
Fig. 4 is optical aberration parameter of the present invention.
Embodiment
Below in conjunction with drawings and Examples content of the present invention is described in further detail.
With reference to Fig. 1, the two heart Kohler illumination light paths far away of the present invention, adopt optical glass, using existing Kohler illumination is initial configuration, by mirror shape, radius-of-curvature etc. are variant, be divided into collecting lens light group and two light groups compositions of condenser light group with 6 lens of light source 1 center arranged in co-axial alignment, from left to right ordering is: light source 1, first meniscus lens 2, second meniscus lens 3, the 3rd concavees lens 4, the 4th convex lens 5, the 5th convex lens 7, the 6th concavees lens 8, be provided with diaphragm 6 between the 4th convex lens 5 and the 5th convex lens 7, light source 1 projects unlimited distance with light beam after the said lens system.
Described collecting lens light group is comprised of the 3rd concavees lens 4, the 4th convex lens 5 of tactic first meniscus lens 2, second meniscus lens 3 and gummed, described condenser light group is comprised of the 5th convex lens 7 and the 6th concavees lens 8, and 6 of diaphragms between the two light groups also are the object space focal planes of condenser light group for the picture side focal plane of collecting lens light group the time.
Consisting of between collecting lens light group and the condenser light group is two telecentric systems, and light beam is parallel beam around here, in condenser light group, between the 5th convex lens 7 and the 6th concavees lens 8 a very little spacing is arranged, thereby can carry out certain spacing and regulate.
Fig. 2 is optics point range figure of the present invention and wavelength data figure, reflects the illumination uniformity coefficient of each visual field.
Fig. 3 is optical assessment function MTF figure of the present invention, reflects overall picture element situation.
Fig. 4 is optical aberration parameter of the present invention, reflects the aberration situation.
The two heart Kohler illumination light paths far away of all things considered the present invention, its number of lenses is than having lacking of similar Lighting Design both at home and abroad now, image quality is good, structure and to debug technique simple, cost is lower, and cost performance is higher, the illuminator that can be used for the accurate detection field of the higher microelectronics of alternative cost, be widely used on the various photoelectric metering instruments, suitable with the telecentric objective that metrology and measurement is used, therefore have broad application prospects and commercial value.