DE102008045671A1 - Fluorescent microscope, especially for rock studies, has an integrated LED light source for use in the field - Google Patents

Abstract

The fluorescent microscope, especially for rock studies, has an integrated light source (1*) as a white LED. An excitation filter (3) can be moved in and out of the light beam path. A barrier filter (8) can be moved in and out of the light beam in front of the eyepiece (10). A ring diaphragm (5) can be moved in and out of the light beam between the light source and the lens (6).

Description

The The invention relates to a fluorescence microscope, in particular for rock investigations, with a light source, in particular one integrated in this Light source.

Fluorescence microscopes become high resolution microscopic examination of both naturally more luminous, that is autofluorescent, than also by intentional addition or unwanted penetration of fluorescent Dyes, so-called fluorochromes, used to make luminous objects. Such investigations are made, for example, in oil and gas exploration, in the remediation of environmental damage, in food technology, in microbiological research as well used in medical diagnostics. Fluorescence microscopes are most commonly used in high-resolution fluorescence microscopy Methods in microbiological research and in numerous clinical procedures for the detection of diseases and their pathogens used. In addition, with the help of fluorescence microscopy in a search and evaluation of petroleum host rocks contained therein Share of petroleum-forming Substances visualized and from already formed petroleum or impurities distinguished from a drilling operation. In addition, fluorescence microscopy is the quality control in food technology and in the detection of finely divided organic particles, eg. As in contaminated soil, sewage sludge, garbage or fungus in wood and used in the living area.

basis Fluorescence microscopy is the property of numerous Substances, in particular organic compounds, when irradiated or Excitation with short-wave light or UV radiation in turn longer-wave and generally give off visible light, which is fluorescence referred to as. The luminosity of the visible light emitted by such substances is opposite to Excitation light intensity much weaker, so that the visualization of the substances, the short-wave excitation radiation preferably Completely must be filtered out.

Around to produce a sufficiently bright image of the faint emission, be in the various technical realizations of fluorescence microscopy essentially at three points of the microscopic beam path activities to increase and to maintain the luminosity carried out. First, as light sources, particularly strong bulbs are used. Second, filter combinations are used to separate excitation and emission wavelengths used with a high transmission effect. Third, be for focused lighting and picture extremely bright and picture used highly corrected lenses.

Around to meet these conditions based a technical implementation of fluorescence microscopes in Generally on a medium sized until big, composite laboratory or research microscope. Because of the high Requirements for the strength In the short-wave range lighting are generally discharge lamps, z. As mercury vapor lamps or metal halide lamps with the necessary ballasts or alternatively also used strong halogen lamps. To the limit the excitation and emission wavelengths become complex combinations made of metal interference filters and dichromatic beam splitters used in so-called filter blocks. Because of high demands on a resolution and a bright and error-free picture are generally extremely wide open and used highly corrected immersion objectives. A maximum practical resolution is in the range of for Self-luminous values considered as the object to be examined about 1 μm.

used becomes an illuminating and imaging in such fluorescence microscopes Optics, in which the development of strong, highly permeable and self-fluorescence brightfield lenses is in the foreground. The negative characteristics of these lenses, a very low Working distance, high mechanical vulnerability, a necessity the immersion and very high costs were given the vast majority Use of research microscopes in laboratories accepted. In contrast, is the use of the entire illumination beam path for fluorescence through an additional, grazing illumination by means of so-called dark field objectives shortly after introduction incident light fluorescence Forgotten in the 1950s.

newer, compact fluorescence microscopes either offer only one distinct lower resolution, as in the case of so-called modified stereomicroscopes, or they have optically and mechanically complex facilities for Change of different light sources. There are different light sources when using fluorescence microscopy in the known fluorescence microscopes mandatory, as detected by fluorescent lighting Fluorescence phenomena known structures otherwise could not be assigned. In other words, will a consideration of one and the same object used in the microscope twice made, once by fluorescence microscopy and once by means of conventional white light illumination, to recognize the known structures with white light and the clearly assign to fluorescent structures.

Known is also the use of high-performance light-emitting diodes in general. The high-performance LEDs already today offer a luminosity comparable to strong conventional lamps, in particular in the short-wave range of the visible spectrum radiating high-performance light-emitting diodes advantageously no heat radiation submit. Monochromatic or very narrowband emitting LEDs are already being used in microscopes, with several high-power LEDs with different defined frequencies in mechanical and optical consuming change devices are used.

Also the newer fluorescence microscopes have a partly still high Energy requirement, high weight and complex structure. Corresponding Even the newer fluorescence microscopes are very expensive and only for one Laboratory operation suitable. Furthermore they are mechanically vulnerable against damage.

by virtue of a variety of disadvantages are such known fluorescence microscopes for one Field use unsuitable, risky, expensive and difficult to operate Equipment.

Laboratory- or research microscopes are for one Field use too big, too heavy and too bulky. Smaller otherwise known devices are generally as fluorescence microscopes not expandable. Discharge lamps and the necessary ballasts are large, bulky and require electrical services by convention 50 to 250 W, which is not readily available in the field can be. Discharge lamps are also consuming in operation and require frequent, systematic maintenance. Due to implosion hazard and mercury leakage, they also set Security risk.

alternative used halogen lamps are prone to vibration, what they are for a Field use makes it unsuitable. In addition, provide halogen lamps a significantly lower power in the short-wave range, so that she for Fluorescence microscopy are unsuitable.

Either Discharge and halogen lamps emit no intensity-reducing effects countermeasures sometimes extremely strong in the infrared range. The resulting heat damages however often the sample to be examined and poses a risk of injury represents.

Generally known filter blocks for filtering light are for many applications too expensive, too expensive or too inflexible.

highly corrected Immersion lenses are for the tasks in many technical fields generally inappropriate, since the immersion medium affects the sample, the course is microscopic Investigation slows down and additional cleaning required. Their short working distances are too rough for rough surface samples too low.

With usually used bright field objectives is not dark field observation possible, like she for the observation of the intrinsic colors of objects to be examined required is.

There a current research fluorescence microscope at least 20,000 Euro costs, is the use for a field operation as well economically risky. In addition, there are high maintenance costs for the discharge lamps. Theft, accident, contamination, incorrect operation or lack of maintenance therefore put in the field / field service with such a fluorescence microscope is a high risk. Cheaper Fluorescence microscopes, on the other hand, offer only a small amount resolution or they are optically / mechanically complicated produced, which also leads to high costs.

current Developments are even stronger High-performance LEDs, which in the future for example to be used as a front lamp in the automotive sector. In order to substitute for Daylight sources are used to become high power light emitting diodes offered, whose luminous area are coated with fluorochromes. From the resulting mixture of blue excitation and yellow-yellow emission light gives the impression a "white" light source. Due to a very irregular intensity distribution over the frequency range from their designated as "white" light However, such light sources appear only as a substitute for daylighting suitable.

The The object of the invention is a fluorescence microscope with a especially in this integrated light source so simplify that also a use in the field is made possible. It should especially possible be, just prepared Objects, that is Objects with a surface roughness, with sufficient brightness and with low financial, apparative and logistical effort with both daylight-like slate darkfield lighting and observed under high-resolution fluorescence conditions.

These Task is solved by a fluorescence microscope, in particular for rock investigations, with a light source, in particular a light source integrated therein, with the features according to claim 1. Advantageous embodiments are the subject of dependent claims.

Prefers is a fluorescence microscope, especially for rock investigations with a light source, in particular a light source integrated therein, the light source being a "white" light emitting diode light source is trained. Thus, a high-resolution fluorescence microscope can be provided for the Field use, which only a single light source for two lighting methods having. This is eliminated a need for elaborate frames, changing and centering devices for one Variety of different light sources. In addition to a possible Reduction of the structure by eliminating conventional lights and ballasts It is also possible to reduce energy consumption, making it even more than an hour Operation with conventional Batteries enabled becomes.

Prefers is such a fluorescence microscope with one in the beam path behind the light source arranged excitation filter, wherein the excitation filter is removably arranged from the beam path. Through the removable Use of the excitation filter in the beam path is made possible with one and the same "white" light source both an almost monochrome, narrowband illumination of an object with blue light for Fluorescence microscopy and illumination of the object with "white" light for one conventional To enable consideration.

Prefers a blocking filter is arranged in front of each eyepiece in a beam path, wherein the barrier filter removably disposed from the beam path is.

Prefers becomes such a fluorescence microscope, in which in a ray path between the light source and a lens a ring aperture as a darkfield annular aperture is arranged, wherein the annular aperture is removably arranged from the beam path. As a result of that the ring diaphragm is removable from the beam path, can optionally the light of the beam path in full width on the entire lens surface or only on an outer edge area of the lens. Accordingly, fluorescence microscopy or a conventional one Incident light microscopy with grazing light become.

Prefers is such a fluorescence microscope with a lens, where the lens is designed as a bright / darkfield lens. The Design as light / darkfield lens supports the optional applicability of the fluorescence microscope for both fluorescence microscopy and for one conventional Reflected light microscopy, so that under fluorescent lighting detected objects under "white" light recognized objects can be uniquely assigned.

Prefers becomes such a fluorescence microscope in which the lens is a central imaging optics and a surrounding edge area as an illumination optics in particular grazing on all sides Projecting light forms on an object. In particular known per se Bright field / dark field incident light lenses, so-called HD lenses, allow in white light dark field illumination the observation of natural Natural colors of untreated specimen surfaces of an object and are therefore can be used particularly advantageously in a fluorescence microscope. Such lenses offer a characteristic possibility of diffuse imaging reflective surfaces and thus the observation of the natural colors of the examining object. In particular, an embodiment in Connection with a reflected-light microscope allows.

One Beam splitter preferably on the one hand a beam of rays from the light source on a / the lens and on the other hand, a ray tufts of the Lens on / the eyepiece, with the beam splitter as partial permeable Reflector is designed without dichromatic filter function. Due to the Preferred embodiment of the fluorescence microscope is the use of a dichromatic element as a beam splitter because of the change between White- and fluorescent light neither necessary nor desirable, making a simple Reflector can be used.

Prefers continues to be such a fluorescence microscope, which is designed as incident light microscope is.

The Light-emitting diode light source in particular has a light-emitting diode a discontinuous light spectrum.

The Light-emitting diode light source, in particular a / arranged in this Light-emitting diode light preferably radiates with a first spectral Maximum with a maximum wavelength between 400 nm and 550 nm, in particular less than 500 nm, and with a second maximum with a wavelength greater than 500 nm off. In particular, it emits light with a spectrum at the first maximum is narrow band compared to the second maximum is. A minimum of the spectrum between the two maxima has one Intensity, which is significantly lower than that of the maxima. In particular, the intensity of the minimum is less than 30% of the intensity of the higher frequency Maximums with the blue portion of the spectrum.

Prefers is such a fluorescence microscope with only one single light emitting diode as the light source equipped.

Independently advantageous is a use of such a fluorescence microscope when for fluorescence observation on the one hand the excitation filter is chosen such that a primary excitation wavelength range of an object to be examined meets the object and that on the other hand above the excitation wavelength range, in particular from a range of spectral minimum of the LED light source all wavelength be blocked.

This is possible thus advantageous with a combination of a so-called "white" LED and in the beam path usable or removable from this Filter the construction of a for field-applicable high-resolution fluorescence microscope. This eliminates the Need to take samples from a sampling site to a lab which is at the same time related Sources of errors such as errors in a label, a documentation, a loss or contamination of the samples eliminated. There is also no problem with storage and disposal of Samples in a laboratory after their examination. For customer-oriented use and for teaching purposes, there is also the possibility of immediate Demonstration of an observation result on site.

by virtue of the cost-effective Construction of simple and in particular taken by itself commercially Components, a fluorescence microscope can be provided, which, for example, also in engineering offices, small laboratories, schools or Training companies can be provided.

highlight Again, the use of a single lamp in particular for two Lighting methods, an advantageous combination of three modules in the form of a "white" high-performance LED, separate interference filters and a light / darkfield lens, which a reduction of the required devices by Elimination of conventional luminaires and ballasts and one Enable a variety of complex changing facilities. Furthermore, the Energy requirement reduced so that a field use with longer Batteries enabled becomes. The simplification of the illumination beam path allows the Use of conventional Incident light microscopes by simply removing diaphragms from them and the use of a fixed reflector. The actually for inserts except one general room lighting due to their irregularity Spectrum unsuitable appear "white" high-performance LEDs are due to the preferred combination of in particular from the beam path removable filters surprisingly advantageous for the construction of a particularly simple fluorescence microscope suitable.

One embodiment will be explained in more detail with reference to the drawing. Show it:

1 schematically components of a fluorescence microscope with a built-in this light source and

2 individual components used in its beam path.

1 shows schematically and partially in section or through transparent walls illustrated components of a particularly preferred high-resolution fluorescence microscope, which is suitable for field use. Essentially, advantageous components are shown only for the understanding of the basic structure of the beam path.

In a housing 13 is a collector 2 arranged in the form of in particular a lens or a Fresnel element. Front side of the collector 2 is arranged a "white" light-emitting diode light source, which according to the simplest embodiment by a so-called "white" LED 1 is trained.

Optionally, the light emitting diode light source 1* a regulator 10 upstream to be able to control a radiated light intensity of the "white" light. Under the "white" light of the LED light source 1* is understood, as illustrated by an intensity diagram, light, which has a very high short-wave, blue component. Such light is provided by a blue light emitting diode. In order to be able to provide the further spectral components of the "white" or white light to the human eye, an outer surface or a body of the light-emitting diode becomes known in a manner known per se 1 coated with a phosphor, which is excited by the blue light and even emits light with lower frequencies or larger wavelengths. This produces and emits spectral components of the light in the other colors visible to the human eye, with a focus on the yellow and red components. The "white" light thus does not consist of a spectrum customary for "white" sunlight but rather of a spectral intensity curve with a narrowband and intense peak in the blue region and a relatively broadband intensity curve in the higher-wave region. Alternatively, it would also be conceivable to use a blue light-emitting light-emitting diode with an upstream filter which has suitable fluorochromes for generating "white" light.

By the thus provided "white" light is it possible by means of a simple excitation filter 3 which allows only short-wavelength light, in particular only 500 nm, to provide a suitable excitation light for fluorescence microscopy. The excitation filter 3 is preferably in a carriage-like sliding guide or in a pivoting guide within the housing 13 arranged to remove it from the beam path or possibly completely out of the housing 13 to be able to take out. In the removed state, the "white" light from the collector 2 unhindered in the direction of an object 7 forwarded, so that a viewing of the object with "white" light is made possible. By inserting the excitation filter 3 in the beam path or by removing the excitation filter 3 the beam path thus becomes a reflection of the object 7 with fluorescent light or with "white" light allows, so that recognized in fluorescent light structures can be easily assigned to recognized with "white" light structures.

That from the collector 2 via the inserted or unused excitation filter 3 blasted light falls on a beam splitter 4 which is the "white" or the blue light in the direction of a lens 6 deflects. The objective 6 is particularly preferably designed as a bright / dark field lens and focuses the light on the object 7 , From the object 7 reflected light is transmitted through the lens 6 back to the beam splitter 4 steered and partially passes through this straight. That through the beam splitter 4 passed light passes into a observation tube 9 and through this and an eyepiece 10 through in the direction of one eye or both eyes of an observer.

In order to enable a dark field viewing, a ring stop is in the beam path 5 used. Particularly preferred is the annular aperture 5 as a dark field ring aperture in kind z. B. a slider with an additional empty space for completely passing the entire incident light configured and between the beam splitter 4 and the lens 6 arranged.

Another removable component is a blocking filter 8th in the beam path between the beam splitter 4 and the eyepiece 10 used. Depending on the desired lighting of the object 7 are according to the excitation filter 3 , the bezel 5 and the notch filter 8th to insert into the beam path or remove it from the beam path, so that the viewer can set with his eye by simply adjusting these three components either a reflected light view with "white" light or a view with fluorescent light and can set a bright field or a dark field viewing , The three components mentioned can be mechanically combined in such a way that a single adjustment to change between reflected-light viewing with "white" light and viewing with fluorescent light is sufficient.

Other components shown are known for such in the field microscopes known components. That's the lens 6 preferably on a revolver 15 set to be able to swivel other lenses into the beam path instead of this one darkfield lens. The object 7 is on a slide 14 to arrange. For adjusting a distance and the beam paths between the object 7 which is to be examined, and that on the housing 13 seated lens 6 is the case 13 over a tripod 12 and a focus shoot 11 on the slide 14 stored.

2 shows schematically again to facilitate understanding again individual aspects of the preferred fluorescence microscope. From the light emitting diode 1 or their actual integrated light source is emitted blue light. The advantage of a light-emitting diode is that it is small, light, off-grid, durable, robust, safe and cost-effective. A light emitting diode allows efficient conversion of electrical energy into directed light without UV or IR radiation. In particular, their use eliminates the need to filter out thermal radiation.

In order to turn the blue light of the light emitting diode "white" light or to provide a "white" light emitting diode, this is coated with a phosphor. By way of example, cerium-doped yttrium-aluminum garnet may be mentioned, but any further phosphors may be used which, together with remaining portions of the blue light, provide a particularly two-part spectrum. The initially disadvantageous intensity curve of the light spectral components of a "white" light-emitting diode, which makes it unsuitable for purposes other than room lighting, allows surprisingly advantageous use in a fluorescence microscope. The inherent two-part spectrum of the "white" LED 1 allows a simple change between illumination of the object to be examined 7 with blue or "white" light without changing the actual light source by inserting or removing the excitation filter 3 and the blocking filter 8th , Provided by a "white" LED 1 in particular, a light with a high yield of short-wave excitation light and in addition a sufficient proportion of "white" light for white-light observation of the object 7 ,

The right subscription portion of 2 illustrates the advantageous embodiment of the removable annular aperture 5 , With inserted ring diaphragm 5 light falls to illuminate the object 7 le diglich through the outdoor areas 6 * of the lens 6 on the object 7 , When removing the dark field ring diaphragm from the beam path for viewing with "white" light, however, the light falls through the entire surface of the lens 6 on the object to be examined 7 , This is made possible by appropriate adjustment of the ring diaphragm 5 an intensified excitation plus an observation of the intrinsic colors of the object 7 , In particular, the full illumination beam path of the objective can also be utilized 6 and thus optimal illumination of "rough" surfaces of objects to be examined 7 at the same time high resolution by light / darkfield lenses like the lens 6 ,

Particularly preferred components of the fluorescence microscope in combination with each other are the light source emitting the "white" light 1* with a preferably "white" high-performance light-emitting diode 1 , the arrangement of removable interference exciter filters 3 . 8th and the illumination optics with a light / darkfield lens as the lens 6 , In order to provide such a fluorescence microscope, it is possible to resort to otherwise conventional microscope components, which are simplified or modified. For example, radiation-limiting apertures for fluorescence observation can be removed from conventional microscope components. In addition, a simple, large-area beam splitter 4 be used instead of an otherwise conventional dichromatic element or color divider.

In particular, the use of a "white" light-emitting diode as the light-emitting diode is particularly advantageous 1 in the light-emitting diode light source 1* , In contrast to conventional bulbs produce such "white" high-performance LEDs 1 significantly more shortwave light and virtually no heat radiation. In addition, such LEDs emit light without further technical devices in the desired direction. The expended for their operation electric power is therefore lower overall and is much more efficient converted into luminous power than conventional bulbs, which allows use in field operation with power supply from batteries. Due to the already pre-directed radiation is sufficient to bundle the beam path in front of the high-performance light emitting diode 1 a suitably selected condenser as a collector 2 in the form of a lens combination or Fresnel lens. In particular, the use of a Fresnel lens arrangement offers the possibility of further reducing a required overall length of the fluorescence microscope and thus further facilitating its transport to an application in the field.

advantages so-called "white" high-performance light-emitting diodes across from conventional bulbs are in a particularly suitable for fluorescence spectral distribution with a very high blue content of light, in a negligible Thermal radiation, in a low energy requirement with low voltage, in one enabled Battery / rechargeable battery, insensitive to shocks during transport, in a maintenance-free, in a long life, in a dimmability at spectral constancy and a low Price.

Another particularly advantageous aspect is the use of the preferred and removable from the beam path filter in the form of the excitation filter 3 and the blocking filter 8th , Separate interference filters, in particular independent of the manufacturer, and, if appropriate, also inexpensive absorption filters may be used as these filters. Because of the already very efficient limitation of the excitation spectrum by the use of a "white" light-emitting diode light source 1* the requirements for the filter combination are low. In particular, a filtering of heat radiation is unnecessary. As a result, the number of components in the beam path compared to conventional fluorescence microscopes can be reduced, which in addition to a cost reduction and a flexible combination of excitation and blocking filters as needed with respect to the object to be examined 7 allows. In particular, a dichroic reflector is not generally required as a color splitter.

The filters, that is the excitation filter 3 and the notch filter 8th , Can be arranged for quick change between white light and fluorescent light viewing in bills.

As the lens 6 in particular, to provide a simple illumination optics and to image the sample surface of the object 7 Light / darkfield incident light dry lenses used, as they are also known as HD lenses. Such lenses 6 exhibit in an annulus or in its edge area 6 * arranged concentrically around the imaging optics on a lighting optics, which the light coming from the light-emitting diode light source 1* was blasted through the various other components, grazing the object on all sides 7 projected. In contrast to coaxial bright field illumination, such HD lenses are particularly suitable for displaying diffuse reflecting surfaces due to grazing illumination. HD lenses allow the observation of the natural colors of untreated object surfaces of an object to be examined in the case of white light dark field illumination 7 , They are therefore particularly suitable for objects 7 , which can not be prepared consuming or sol len, as is necessary in particular for use in the field.

Particularly advantageous is the possibility of the ring diaphragm 5 to be removed from the beam path. This allows to increase the illumination aperture in fluorescence observation used for dark field observation ring diaphragm to remove from the beam path and so the entire cross section of the beam over the lens 6 including the surrounding annular space or edge area 6 * on the object 7 to steer. Because fluorescent objects 7 The image contrast remains high despite this unregulated mix of direct and grazing lighting.

In both white light and fluorescence observation, achromatic correction of the HD lenses is objective 6 generally sufficient. Advantageously used are therefore standard dry lenses medium to high aperture.

To the entire cross section of the beam over the lens 6 and its surrounding annular space or edge area 6 * on the object 7 to steer is the beam splitter 4 designed as a reflector preferably sized so large that it covers the entire cross-section of the lens 6 including its edge area 6 * illuminates. To suppress unwanted scattered light, the passage of the beam splitter 4 in function as a reflector for that of the light-emitting diode light source 1* emitted light on the observer side to be limited to the diameter of the observation beam path. Preferably, as a beam splitter 4 or reflector used a mirrored, semi-transparent glass plate without filter function. The use of a dichromatic element as a beam splitter 4 is neither necessary nor desirable because of the change between "white" light and fluorescent light.

Because of the greatly reduced size of the required components and because of the unproblematic development of heat compared to known fluorescence microscopes as the tripod 12 a tripod of a simple, compact epi-microscope, that is, a microscope without a transmitted light beam, are used, in itself, from the metallography and the semiconductor industry is known. To observe larger objects, the tripod should 12 be extended by a clamping device and with the focus drive 11 be equipped with a big hub. Monocular, binocular or trinocular observation tubes, in particular, may be used for observation and documentation as the observation tube 9 be used.

In a particularly preferred embodiment for use in the field of geoscientific and geotechnical investigations, a blue excitation by the light emitting diode 1 with its own wavelength maximum around 460 nm and a spectrum extension to the "white" light, a downstream short-pass filter at 500 nm as an emission filter or the excitation filter 3 and the notch filter 8th used as a long pass filter around 520 nm.

feasible But based on this basic principle, it is also a green stimulus with red fluorescence. In principle, with the construction of the fluorescence microscope theoretically every wavelength range be covered by a "white", ie broadband High-performance LED gives. Gallium phosphide or gallium nitride LEDs offer a primary green radiation and let so similar how to modify blue spots to a multi-band component, provided corresponding "white" light-emitting diode light sources should be provided.

In dependence of the sample type, a corresponding high-performance light-emitting diode be used, whose primary Radiation as excitation wavelength for the Fluorescence observation is filtered out. For viewing in the "white" light you leave then all frequencies through.

The Filter selects one accordingly so that on the one hand the primary radiation or excitation wavelength full to the test and that, on the other hand, from the spectral range Minimums everything is blocked. The barrier filter or barrier filter is chosen that the wavelengths the fluorescence radiation of the sample are transmitted. For geoscientific Purposes the fluorescence radiation is transmitted as completely as possible. Especially in other areas, such. B. biotechnology and medical technology, can Also selective filters are used as band filters, which only the wavelengths let through, which come from specific molecules.

Claims (12)

Fluorescence microscope, in particular for rock investigations, with a light source ( 1* ), in particular with a light source integrated therein, characterized in that the light source ( 1* ) is formed as a "white" light-emitting diode light source. Fluorescence microscope according to claim 1, with one in the beam path behind the light source ( 1* ) arranged excitation filter ( 3 ), wherein the excitation filter ( 3 ) is removably arranged from the beam path. Fluorescence microscope according to claim 1 or 2, wherein in a beam path in front of an eyepiece ( 10 ) a blocking filter ( 8th ), wherein the blocking filter ( 8th ) is removably arranged from the beam path. Fluorescence microscope according to any preceding claim, wherein in a beam path between the light source ( 1* ) and a lens ( 6 ) a ring diaphragm ( 5 ) is arranged as a dark-field annular diaphragm, wherein the annular diaphragm ( 5 ) is removably arranged from the beam path. Fluorescence microscope according to any preceding claim with a lens ( 6 ), where the lens ( 6 ) is designed as a bright / darkfield lens. Fluorescence microscope according to Claim 5, in which the objective ( 6 ) a central imaging optics and a surrounding edge region ( 6 * ) as an illumination optics for grazing projecting light onto an object ( 7 ) trains. Fluorescence microscope according to any preceding claim, in which a beam splitter ( 4 ) on the one hand a beam path from the light source ( 1* ) on a lens ( 6 ) and on the other hand a beam path from the lens ( 6 ) on an eyepiece ( 10 ), wherein the beam splitter ( 4 ) is designed as a partially transmissive reflector without dichromatic filter function. Fluorescence microscope according to any preceding claim, which is designed as incident-light microscope. Fluorescence microscope according to any preceding claim, wherein the light-emitting diode light source ( 1* ) a light emitting diode ( 1 ) having a discontinuous spectrum of light. Fluorescence microscope according to any preceding claim, wherein the light-emitting diode light source ( 1* ), in particular a / in this arranged light emitting diode ( 1 ) Emits light with a first spectral maximum with a maximum excitation wavelength between 400 nm and 550 nm, in particular less than 550 nm, and a second maximum with a wavelength greater than 500 nm, in particular emits light with a spectrum in which the first maximum narrowband in comparison to the second maximum. Fluorescence microscope according to any preceding claim with only a single light-emitting diode ( 1 ) as a light source. Use of a fluorescence microscope according to any preceding claim, wherein for a fluorescence observation on the one hand an excitation filter (s) ( 3 ) is selected such that a primary excitation wavelength range of an object to be examined ( 7 ) on the object ( 7 ) and that on the other hand, above the excitation wavelength range, in particular from a range of a spectral minimum of the light-emitting diode light source ( 1* ) all wavelengths are blocked.