Optical: systems and elements – Compound lens system – Microscope
Reexamination Certificate
2000-04-13
2004-01-13
Cherry, Euncha (Department: 2872)
Optical: systems and elements
Compound lens system
Microscope
C359S389000
Reexamination Certificate
active
06678089
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
This invention claims priority of a German filed patent application DE-A-199 14 049.9.
FIELD OF THE INVENTION
The invention concerns a microscope, preferably a confocal laser scanning microscope, having a light source, a detector, and two objectives, one of the objectives being arranged on each of the two sides of the specimen plane and the objectives being directed toward one another and having a common focus, and at least one beam splitter for distributing the illuminating light to the objectives, and a beam recombiner for combining the detected light coming from the objectives, being provided in the illumination/detection beam path.
BACKGROUND OF THE INVENTION
Microscopes of the generic type, in particular microscopes in which two objectives that are directed toward one another and have a common focus in the image plane are provided, have been known in practical use for some time. Reference is made in this context, merely by way of example, to EP 0 491 289 B1. This document discloses a double confocal scanning microscope having the generic features. Specifically, what is described therein is a scanning microscope in which a non-polarizing beam splitter apparatus is provided to split the illuminating light into coherent portions. The beam splitter apparatus serves to illuminate the objectives directed toward one another, and to combine mutually coherent light beams from the objectives that are directed toward one another. High resolution can be obtained with the optical components implemented therein.
The microscope known from EP 0 491 289 B1 is a so-called “high-end” microscope, in which an interferometric beam path is implemented. A microscope of this kind is of extremely complex design and is therefore—even in its basic version—expensive compared to conventional microscopes. In addition, these “high-end” microscopes are special constructions that require a great deal of room on optical benches and accordingly are also very susceptible to external influences. Above all, however, the “high-end” microscopy provided for therein requires a special microscope, with no possibility of using conventional microscopes with their capabilities.
SUMMARY OF THE INVENTION
It is therefore the object of the present invention to be able to implement the ultrahigh-resolution microscope technique known from the generic existing art in conventional microscopes, for example in confocal laser scanning microscopes, in particular also by retrofitting.
The aforesaid object is achieved by a microscope which comprises at least one light source, at least one detector, and two objectives, one of the objectives being arranged on each of the two sides of the specimen plane and the objectives being directed toward one another and having a common focus; at least one beam splitter for distributing the illuminating light to the objectives, and a beam recombiner for combining the detected light coming from the objectives, being provided in the illumination/detection beam path; a modular assembly for grouping the objectives and the beam splitter/beam recombiner therein and an interface is provided with the modular assembly for connection to the illumination/detection beam path of the microscope.
In addition, the above object is achieved by a confocal laser scanning microscope comprising at least one detector, and two objectives, one of the objectives being arranged on each of the two sides of the specimen plane and the objectives being directed toward one another and having a common focus; at least one beam splitter for distributing the illuminating light to the objectives, and a beam recombiner for combining the detected light coming from the objectives, being provided in the illumination/detection beam path; a modular assembly for grouping the objectives and the beam splitter/beam recombiner therein and an interface is provided with the modular assembly for connection to the illumination/detection beam path of the microscope.
According to the present invention, it has firstly been recognized that conventional microscopes, for example confocal laser scanning microscopes, can be equipped at a later time with ultrahigh-resolution microscope techniques without thereby sacrificing the actual nature of the conventional microscope. It has furthermore been recognized that ultrahigh-resolution microscope techniques can be implemented in conventional microscopes even after the fact, specifically by the fact that the essential components that are responsible for the ultrahigh-resolution microscope technique are grouped into a retrofittable assembly. According to the present invention, therefore, the objectives and the beam splitter/beam recombiner are grouped into a modular assembly. This assembly has an interface for connection to the illumination/detection beam path of the microscope. Considered in and of itself, the modular assembly can be handled independently and can be connected with its interface to the microscope, a connection to the illumination/detection beam path being indispensable.
Advantageously, the assembly can be introduced with its interface into the microscope stand in place of a conventional objective or objective nosepiece, and thereby connected into the microscope (into its illumination/detection beam path). Conversion can thus be accomplished in simple fashion, namely after removing the objective or objective nosepiece, thereby making possible connection of the high-end assembly under discussion here.
In terms of a concrete embodiment of the assembly comprising the optical components, the components of the assembly are mounted on a baseplate. To prevent any temperature-related change in the beam path, it is particularly advantageous if the baseplate is manufactured from a material having a low coefficient of thermal expansion. Materials such as Invar or Super-Invar are thus suitable. These materials have almost no thermal expansion over the range of temperatures occurring here, so that any temperature-related change in the beam path or any corresponding misalignment can be almost ruled out.
In terms of particular secure positioning of the optical assembly, it is further advantageous if the optical components of the assembly—preferably arranged on the baseplate—are arranged in a housing. To eliminate external influences, the housing could be hermetically sealed. Thermal insulation is also advantageous, specifically in order effectively to eliminate external temperature influences on the alignment.
In order effectively to prevent any misalignment, it would be possible to define inside the housing a defined temperature in whose vicinity the beam is aligned. In order to maintain this temperature, the optical assembly could comprise a component having a defined and at least largely constant heat emission. The heat-emitting component would need to be dimensioned so that it is suitable for keeping the assembly at a constant operating temperature, specifically in consideration of the thermal insulation possibly implemented therein. The heat-emitting component could be a laser light source, preferably a diode laser.
A further possibility for eliminating any misalignment due to thermal expansion is that the optical components of the assembly are designed, and are installed and arranged on the baseplate (optionally by way of special holders), in such a way that temperature-related expansions compensate for one another and therefore have no effect on the optical alignment state of the assembly. Very particularly, this can be implemented if individual components are designed such that they exhibit exclusively a linear expansion, i.e. an expansion in one direction. By way of corresponding end-located mounts and expansion characteristics in opposite directions from one another, it is possible for mutual compensation to occur as the temperature changes, with no change in the beam path. This action, too, at least largely prevents any misalignment.
The optical assembly could have further optical components in addition to the two objectives directed oppositely to one another
Bradl Joachim
Engelhardt Johann
Cherry Euncha
Foley & Lardner
Leica Microsystems Heidelberg GmbH
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