DD288244B5 - microscope objective - Google Patents

Description

All lenses mentioned are together a small working distance of a few tenths of a millimeter as well as an IaU alor chromatic aberration, which must be compensated by another optical system - eyepiece, projective.

Also known from the journal Jenaer Rundschau 1/1982, a GF plano-roach 10Ox / 0.90 oo / O-A with a free working distance of 0.25mm.

The small free working distance affects a trouble-free dark field illumination with n.A.> 0.9 in the on-light and requires a restriction of the displacement range of the microscope stage with inverted microscopes.

Object of the invention

The invention is intended to significantly increase the information content in high-resolution, immersion-free microscopic imaging according to quantity and quality. ·

Explanation of the essence of the invention

The invention has for its object to provide a high-resolution dry lens with the n.A. 20,90 and 100 times magnifying image of an object on a field of view with the field number>: 25 mm - corresponding to an object field 2y> 0.25 mm - to create as large a free working distance, the image in the entire field simultaneously sharp, i. diffraction-limited, and Farbsaumfrei-without chromatic magnification difference-occurs and both bright field imaging and largely trouble-free dark field imaging in Aufl'cht is possible. Furthermore, the objective according to the invention in inverted microscopes should ensure a large displacement range of the microscope stage and thus of the object to be examined.

The object is achieved in that the microscope objective is constructed of dreilinsiger positive front group, the first two lenses menisci, the hollow surface facing the object, from subsequent at least three, fluorspar or similar glass containing Kittgliedern and, the objective side final two two-pronged, seriate-shaped cemented elements, and further characterized in that at least the object side first of the cemented members consists of a respective negative lens and a positive lens and that the last of the total of at least three cemented members, as well as the subsequent penultimate cemented member are bilateral menisci with image-side hollow surface and that the last cemented member has the hollow surface facing the object, where furthermore:

1. In the lens-side first cemented member, the amount of the focal length of the negative lens is smaller than the Bronnweite of the positive lens.

2. The penultimate cemented component consists of a positive lens with a refractive index η 1.65 and an Abbe's number ν <35 and a negative lens with a refractive index η> 1.55 and an Abbe's number ν a 50.

3. The last cemented element has a negative focal length, the amount of which is less than ten times the lens focal length. It may be particularly advantageous if two zweilinsige cemented elements are arranged between the object side first and last two-lingual, fluorspar or glass fibers similar, containing Kittgliedern.

This embodiment is particularly easy to produce, since two-part cemented components, one of which is made of fluorspar or flux-like glass, show no technological difficulties and ensure a high centering accuracy in the manufacturing process.

A further embodiment with less optical complexity arises when between the object side first and last two-stranded, fluorspar or similar glass containing Kittgliedern a dreilinsige Kittgruppe is arranged, whose middle lens is made of fluorspar or flußspatähnlichem glass. The triple putty member replaces two double putty members.

By coupling the object side first cemented member with the last two cemented elements in front of the image plane is achieved due to the specified conditions for these cemented members that the lens is CVD-free and thus the lateral color aberration is eliminated. Achieving a large working distance is achieved mainly by the strongly dispersing effect of the last meniscus-shaped cemented element in connection with the tripartite front group. This allows the formation of the lens as an HD system with trouble-free dark field imaging in reflected light and a large lateral displacement range of the microscope stage in inverted microscopes.

The large, leveled image field is achieved in particular by the inventive design of the last three cemented elements whose Petzvalsummen have the sign of a negative lens and compensate Petzvalsummen the preceding lenses or cemented such that the Petzvalsumme the microscope objective is zero or the sign of Negativlinso and a such balance has that the field curvature of a conventional large-field eyepiece at least partially compensated

It is not difficult to see that the different design of the central objective part, instead of two dual groups, a triple group, only one particular embodiment of the objective according to the invention.

Ausführungsbolsplel

The invention will be explained in more detail with reference to an embodiment and a drawing. The figure shows the lens sectional image of an objective according to the invention according to the claims 1-3.

The lenses and lens members are arranged along the optical axis 0-0 '.

A three-stranded front group I, II, III after Jnet are two-branched putty groups IV, Va, Vb, Vl, one of which is each made of fluorspar or latex-like glass, and the objective is completed by two two-lobed putty groups VII, VIII.

In the table to the third claim, the optical data of a system are given according to the figure, wherein mean

Kr = radii of curvature of the lens surfaces in consecutive numbering from the front surface in the direction of the image and axial vertex distances of the lens surfaces in the same numbering sequence and η and ν respectively are refractive indices or payoff of the glasses used in the same numbering sequence, relative to the wavelength = 546.07 μm ,

With d _o , the object distance is called. The object distance of 1.863 min achieved in the exemplary embodiment corresponds approximately to a free working distance of 0.9 mm.

By professional calculation, the putty groups Va and Vb can be replaced by a triple putty group. .

Claims (4)

claims: 1. at the lens side first cemented member (IV), the amount of the focal length of the negative lens is smaller than the focal length of the positive lens 1. Microscope objective, consisting of a triangular positive front group, whose first two lenses are menisci, the hollow surface of which faces the object, from which at least three, fluorspar or flux-like glasses containing, cemented elements and, the lens on the image side, two bivalve, meniscus-shaped cemented composites, characterized in that at least the object side of the first Kittglieder (IV) consists of a respective nepil lens and a positive lens and that the last of the total of at least three Kittylieder (Vl), as well as the subsequent penultimate Kittglied (VII) are two-lingual menisci with image-side hollow surface and that the last cemented element (VIII) has the hollow surface facing the object, wherein furthermore: 2. Microscope objective according to claim 1, characterized in that between the object side first (IVj and last (Vl) zweiiinsigen, fluorspar or glass fibers similar Kätgliedern two zweilinsige cemented elements (Va, Vb) are arranged. 2. the penultimate cemented element (VII) consists of a positive lens with a refractive index η> 1.65 and an Abbe number ν <35 and a negative lens with a refractive index η 2: 1.55 and an Abbe number ν> 50 3. microscope objective according to claim 2, characterized in that the lens is described by the following data set, all dimensions are given in mm: magnification: 100x, focal lengths: 2.5mm, numerical aperture: 0.9 η = radii of curvature of the lens surfaces in consecutive numbering from the front surface in the direction of the image and dj = axial vertex distances of the lens surfaces in the same numbering sequence and ni or Vj are refractive indices or Abbezahlen the glasses used in the same numbering sequence based on the wavelength = 546.07 μιτι. 3. The last cemented element (VIII) has a negative focal length whose magnitude is less than ten times the object's focal length. 4. microscope objective according to claim 1, characterized in that between the object side first (IV) and last (Vl) zweilinsigen, fluorspar or similar glass containing Kittgliedern a dreilinsige putty group (V) is arranged, the middle lens of fluorspar or flußspatähnlichem glass , For this 1 page drawing Field of application of the invention The invention relates to a high-magnification, immersion-less microscope objective with particular suitability for bright and dark field illumination in the optical microscope print. Characteristic of the known state of the art In microscopy, the high-aperture dry lenses are becoming increasingly important. Microscope lenses with the num. Apertures of about 0.9 to 0.95 and a magnification of about 100 times allow the highest resolution of such microscopic details that should or must be observed without immersion. Often it is desirable to carry out the microscopic observations from the weakest to the highest magnification without immersion liquid in order to avoid the laborious change with and without immersion liquid. Sometimes it is essential to avoid contact of the preparations with an immersion liquid, as is the case in important applications in Aufmichtmikroskopie, z. B. in the microelectronics industry. It is also desirable in reflected-light microscopy that even the high-aperture dry systems be suitable for bright and dark field illumination and can be used for both upright and inverted microscopes. DE-OS 2043638 describes a 100 times-increasing dry objective with the n.A. = 0.9, which is composed of 10 lenses in 7 groups. Although it allows a high resolution in the center of the image, but can due to the field curvature characterizing high Petzval total only a small flat object field of about 2y <0.1 mm sharp. In addition, it is expressly intended only for cover glass-covered preparations that are observed in transmitted light. In DE-AS 2327218 a further high-magnification dry lens with 100 times magnification and n.A. = 0.9 is given, which also allows high resolution in the center, but due to strong coma error also allows only a small planar object field simultaneously sharply , In DE-PS 3326352 is a greatly enlarging drying system with lOOfacher magnification and a n.A. = 0.95 indicated. This lens is also intended only for a relatively small object field of 2y <0.2 mm.