DE102008032337A1 - Microscope objective for viewing object in imaging-and incident illumination optical path, has lens group arranged in incident illumination tube lens and partially permeable mirror of mirror arrangement - Google Patents

Abstract

The objective has a lens group (LG1) arranged within an objective adjusting length (a), and another lens group (LG2) provided in a mirror arrangement (10), which is arranged downstream to the former lens group. A third lens group (LG3) is arranged in an incident illumination tube lens and a partially permeable mirror of the mirror arrangement. The former lens group comprises a lens with positive refractive power and another lens with negative refractive power. The latter lens group is formed as a cement element with a positive refractive force.

Description

The The invention relates to a lens with a small magnification for microscopes, in particular a lens composed of several members for overview observations in a big one Facial field.

In modern microscopes become common Lenses used to observe objects that are at infinity corrected. In doing so, the object passes through the microscope objective depicted in the infinite. The lens is followed by a tube lens, which generates an intermediate image of the object in an intermediate image plane, which can be observed through the eyepiece. The enlargement of a such microscope results from the ratio of the focal lengths of Tubuslinse and lens, where the focal length of the tube lens is usually between 160 mm and 200 mm. At a focal length of the lenses between 1.6 mm and 20 mm then result microscope magnification between 10x and 100x.

The Construction of such lenses requires no special measures to shift the main levels, as these are quite good in the for lenses prescribed adjustment length from 45 mm to 60 mm can be accommodated. Overview lenses with enlargements of about 1-fold have a focal length, which depends on the focal length the tube lens deviates only slightly, so a focal length between 160 mm and 200 mm. It is therefore difficult, this relatively large value in the short adjustment length from 45 mm to 60 mm.

It Therefore lens designs have been developed by the teletype, which is an overall length have shorter as the focal length is. This was achieved by a combination a positive (collecting) objective part and a negative (dispersing) part Lens part, but only with a reasonable effort and Satisfactory imaging properties succeed when the ratio between Focal length and length does not exceed a value of approx. At a ratio from focal length to length of 4 would result in very complicated and costly constructions, to the desired To come to success.

Known solutions for overview lenses for the Microscopy is very complicated due to the large number of lenses built and therefore costly and the image quality is insufficient. In particular, occur because of the large number of lenses in incident light applications unwanted, disturbing Reflexes on.

So the invention is based on the object, a lens with a small magnification for microscopes to create, which in a structurally simple construction langbrennweitig and powerful and has good imaging properties.

According to the invention this Task with a lens with a small magnification for microscopes solved with the means set out in the first claim. In the dependent claims are details and designs disclosed the invention.

So it is advantageous that a first lens group having a lens positive power and, downstream, a lens with negative power Refractive power includes that a second lens group as a cemented member is formed with a positive refractive power and that a third Lens group consists of a lens with negative refractive power.

From It is also advantageous if the second lens group consists of a lens with negative refractive power and a lens with positive refractive power consists, wherein the lens with negative refractive power the partially transmissive mirror is arranged facing. This lens group is in the imaging beam path arranged and used to represent the object.

The third lens group of the lens is located in the illumination beam path of the microscope.

An advantageous embodiment of a microscope objective according to the invention with a focal length of 164.5 mm and a working distance of 15.4 mm is realized by the following design data: LG Radius r [mm] Thickness d [mm] n _{e e} LG1 26861 5.0 1.9105 31.41 LG1 -917943 2.8 LG1 -50,939 19.3 1.5510 45.47 LG1 4427 81.25 LG2 408919 1.0 1.6241 36.11 LG2 42415 2.5 1.4984 81.00 LG2 -43,441 LG3 -56,000 1.5 1.5187 63.96 LG3 56,000 where n _{e are} the refractive indices and ν _{e is} the Abbe number.

With the solution according to the invention a structurally simple and constructed with a few optical elements Microscope lens with a small magnification and a large working distance created, which is powerful and long-burning and good Has imaging properties.

The Invention will be explained in more detail below using an exemplary embodiment. In the drawing show

1 the basic structure of a modern microscope according to the prior art,

2 the basic structure of a microscope with an objective according to the invention,

3 the structural design of an objective according to the invention for imaging and

4 a lens group of the objective according to the invention for incident illumination.

In 1 shows the basic structure of a modern microscope according to the prior art. Such a microscope comprises a lens 1 , which for the realization of an imaging and Auflicht illuminating beam path with all its lenses and lens groups within the adjustment length a, as the distance between the mounting surface 2 of the lens 1 on the microscope tube and the object plane 3 is defined, is arranged. The lens 1 downstream of the light direction is usually a mirror arrangement 4 with a partially transparent mirror 5 for coupling the Auflichtbeleuchtungsstrahlenganges, in which advantageously ei ne Auflichttubuslinse 6 is provided. In the imaging beam path of the microscope is the lens 1 or the mirror arrangement 4 a tube lens 7 subordinate, by which in the object level 3 lying object in the Okularzwischenbildebene 8th is pictured, from where it passes through the eyepiece 9 can be observed.

In transmitted light observation of the object, the illumination with parallel light through the object takes place from below. The image of the object in the eyepiece intermediate plane 8th in the imaging beam path takes place through the complete lens 1 and the tube lens 7 through the partially transparent mirror 5 therethrough. There are also microscopes in which the mirror 5 can be removed from the imaging beam path.

In reflected-light illumination, the object is illuminated by the incident-light tube lens 6 , the mirror 5 and the complete lens 1 , The actual image of the object takes place in the illustrated example also by the complete lens 1 through the mirror 5 through and through the tube lens 7 in the eyepiece intermediate plane 8th , The entrance pupil of the lens 1 lies at infinity and the incident light tube lens forms the reflected light in the exit pupil of the lens 1 from.

2 shows the basic structure of a microscope equipped with a three-part objective according to the invention, the objective having a plurality of lens groups LG1; LG2 and LG3 includes. The lens groups LG2 and LG3 are advantageously part of a mirror arrangement 10 with the mirror 5 which lens group LG1 of the objek tivs 11 downstream in the direction of light. The lens group LG2 is part of the objective in the imaging beam path after the mirror 5 and the lens group LG3, also a component of the objective according to the invention, is in the reflected-light illumination beam path, in the light direction in front of the mirror 5 arranged, wherein at the Determining the direction of light is assumed by the respective illumination source.

The lens group LG3 has a negative power, is between the incident light tube lens 6 and the mirror 5 arranged and is not involved in the actual image of the object in the Okularzwischenbildebene. It occurs only in reflected-light illumination and causes the virtual image of the incident light to be in the position of the lens group LG2 at which the exit pupil of the objective according to the invention is located.

The structural design of the object-imaging lens groups LG1 and LG2 of the objective according to the invention is shown in FIG 3 shown. The lens group LG1 is composed of a lens L1 having positive refractive power and a lens L2 having negative refractive power, which are separated by a small air d. ₂ The lens group LG2 is formed as a cemented member consisting of a lens L3 having a negative refractive power and a lens L4 having a positive refractive power, the lens L3 being the mirror 5 is facing.

4 FIG. 4 shows the lens group LG3, which together with the lens group LG1 forms the reflected-light illumination beam path, which advantageously consists of a single lens L5 with a negative refractive power.

The design data of an embodiment of an objective according to the invention with a focal length of 164.5 mm and a working distance of 15.4 mm are set out in the table below, wherein the actual data may well deviate from the given data within the scope of manufacturing tolerances. Table: LG Radius r [mm] Thickness d [mm] n _{e e} LG1 26861 5.0 1.9105 31.41 LG1 -917943 2.8 LG1 -50,939 19.3 1.5510 45.47 LG1 14427 81.25 LG2 408919 1.0 1.6241 36.11 LG2 42415 2.5 1.4984 81.00 LG2 -43,441 LG3 -56,000 1.5 1.5187 63.96 LG3 56,000 where n _{e are} the refractive indices and ν _{e is} the Abbe number.

The The invention has been described in relation to a particular embodiment. It is for However, a person skilled in the art, of course, that modifications and changes carried out can be without while leaving the scope of the following claims.

1

lens

2

bolting

3

object level

4

mirror arrangement

5

mirror

6

Auflichttubuslinse

7

tube lens

8th

Okularzwischenbildebene

9

eyepiece

10

mirror arrangement

11

lens

LG1 LG3 ...

lens group

L1 ... L5

lens

a

balancing length

Claims (4)

Lens with a small magnification for microscopes for realizing an imaging and incident illumination beam path, comprising a plurality of lens groups, characterized by - a first lens group (LG1), which is arranged within the usual lens alignment length a, - a second lens group (LG2), which in one, in the beam path of the microscope of the first lens group LG1 downstream mirror arrangement ( 9 ) is provided and which part of the lens ( 11 ) for the imaging beam path - and a third lens group (LG3), which in the reflected light illumination beam path between a Auflichttubuslinse ( 6 ) and a partially transparent mirror ( 5 ) of the mirror arrangement ( 9 ) is arranged. Microscope objective according to claim 1, characterized - that the first lens group (LG1) has a lens (L1) with positive refractive power and, downstream of this, a lens (L2) with negative refractive power includes, - that the second lens group (LG2) as a cemented component with a positive Refractive power is formed - and that the third lens group (LG3) consists of a lens (L5) with a negative refractive power. Microscope objective according to claim 2, characterized in that the second lens group (LG2) consists of a lens (L3) with negative refractive power and a lens (L4) with positive refractive power, wherein the lens (L3) with negative refractive power of the semitransparent mirror ( 5 ) is arranged adjacent. Microscope objective according to one of Claims 1 to 3, characterized by the following design data for a lens ( 11 ) with a focal length of 164.5 mm and a working distance of 15.4 mm: LG Radius r [mm] Thickness d [mm] n _{e e} LG1 26861 5.0 1.9105 31.41 LG1 -917943 2.8 LG1 -50,939 19.3 1.5510 45.47 LG1 14427 81.25 LG2 408919 1.0 1.6241 36.11 LG2 42415 2.5 1.4984 81.00 LG2 -43,441 LG3 -56,000 1.5 1.5187 63.96 LG3 56,000 where n _{e are} the refractive indices and ν _{e is} the Abbe number.