Adapter for microscope

Abstract: The present invention concerns an adapter (22) to be coupled to an objective lens (18) of a microscope comprising a body member having a first coupling means (34) at one end thereof to receive an objective lens (18) of a microscope and having a second coupling means (38) at the other end thereof to receive a microscope component (14). The body member has an axial light path running longitudinally therethrough and has a radial light path which intersects the axial light path. A source of light (24) is disposed in the radial light path. A first filter (28) is disposed in the radial light path downstream of the source of light for passing light at wavelengths which excite fluorescence in a specimen to be examined in a microscope and to remove light at wavelengths where visible fluorescence emission occurs in the specimen. A mirror (30) is disposed in the intersection of the axial light path and radial light path. The mirror (30) passes light through the axial light path and reflects light at excitation wavelengths, but does not reflect light at emission wavelengths. A second filter (32) is disposed in the axial light path and is disposed above the mirror (30) and adjacent the second coupling means (38). The second filter blocks excitation wavelengths which pass through the mirror. The adapter (22) can easily be attached and detached to a conventional microscope. The adapter can provide fluorescence microscopy capability to a conventional microscope which was not designed for fluorescence microscopy.

Description: Field of Invention The present invention concerns an adapter for an objective lens of a microscope. More particularly, the present invention relates to an adapter which converts an ordinary microscope into a fluorescent microscope. Background Information Microscopes are described in the following U.S. Patents: 1,837,993; 3,846,008; 4,362,355 and 4,744,642, the entire contents of such U.S. patents being incorporated by reference herein. Fluorescence microscopy uses a fluorescent compound to identify microscopic structures. Commonly, the fluorescent compound is attached to an antibody, and the antibody attaches itself to a corresponding antigen on a cell. The cell is then examined under a fluorescence microscope. Fluorescent areas within the cell indicate the presence and location of the antigen. Although fluorescent microscopy is a very sensitive technique, its use is limited by the expense of the specialized equipment required. Current fluorescent microscopes are designed specifically to provide for fluorescence illumination and filtering. Most use a high pressure mercury vapor lamp as a source of illumination. The lamps themselves are expensive, and they require a complex power supply. The illumination source occupies about as much room as the microscope itself and generates substantial heat. Due to the specialized equipment and complexity, fluorescent microscopes generally cost two to four times the cost of corresponding professional quality bench microscopes. The light source and power also make them more bulky, occupying substantially more bench space than conventional microscopes. GB-A-1 447 166 discloses an adapter for supporting at least one objective lens of a microscope comprising: a body member having a first mounting means at one end thereof and having a second mounting means at the other end thereof to detachably mount a microscope component, said body member having an axial light path running longitudinally therethrough and having a radial light path which intersects the axial light path, a source of light disposed in the radial light path, a first filtering means disposed in the radial light path, downstream of the source of light, for passing light at wavelenghts which excite fluorescence in a specimen to be examined in the microscope and to remove light at wavelengths where visible fluoroscence emission occurs in the specimen, a reflecting means disposed in the intersection of the axial light path and radial light path, the reflecting means passing light through the axial light path and reflecting light at excitation wavelengths, but not reflecting light at emission wavelengths and a second filtering means disposed in the axial light path and disposed above the reflecting means adjacent the second mounting means, the second filtering means blocking excitation wavelengths which pass through the reflecting means. SUMMARY OF THE INVENTION It is an object of this invention to provide fluorescence microscopy capability to a microscope which was not designed for fluorescence microscopy. It is a further object of this invention to provide this capability in the form of a user installable attachment. It is another object of this invention to provide an attachment which can be installed on the majority of professional quality microscopes. It is a further object ot this invention to provide an adapter for a microscope that can be easily attached and detached from the microscope. It is still another object of the present invention to provide a microscope adapter which can be utilized on conventional microscopes to provide sufficient fluorescence microscopy to inexpensively and efficiently detect infectious diseases, for example malaria. The above objects, as well as other objects, aims and advantages are satisfied by the present invention as defined in the claims. The present invention concerns an adapter with the above mentioned features known from GB-A-1 447 166 and being characterised in that said first mounting means is arranged for detachably mounting directly to an objective lens of the miscroscope. Professional quality microscopes in common use have removable objective lenses with standard threads. The focusing mechanism of such microscopes allow for the mounting threads for the objective to be moved away from the stage to make room for the inventive adapter. The present invention concerns an adapter to be coupled to an objective lens of a microscope comprising a body member having a first (detachable) coupling means at one end thereof to receive an objective lens of a microscope and having a second (detachable) coupling means at the other end thereof to receive a microscope component. The body member has an axial light path running longitudinally therethrough and has a radial light path which intersects the axial light path. A source of light is disposed in the radial light path of the body member. A first filtering means is disposed in the radial light path of the body member, downstream of the source of light, for passing light at wavelengths which excite fluorescence in a specimen to be examined in a microscope and to remove light at wavelengths where visible fluorescence emission occurs in the specimen. A reflecting means is disposed in the intersection of the axial light path and radial light path. The reflecting means passes light through the axial light path and reflects light at excitation wavelengths, but does not reflect light at emission wavelengths. A second filtering means is disposed in the axial light path and is disposed above the reflecting means adjacent the second coupling means (the second filtering means is disposed between the reflecting means and the eye piece of a microscope in which the adapter is installed, i.e., the second filtering means is disposed between the reflecting means and the observer's eye). The second filtering means blocks excitation wavelengths which pass through the reflecting means. The present invention also concerns a combination of an adapter as described above and a microscope. The microscope comprises a vertical body tube, an eye piece disposed at one end of the body tube, an objective lens disposed at the other end of the body tube and a means for retaining a specimen plate under the objective lens. The adapter is coupled to the body tube and to the objective lens of the microscope. Preferably the adapter is detachably coupled to the body tube. Preferably the turret is detachably coupled to the objective lens. The adapter is aligned so as to form a longitudinal axial light path through the body tube, the adapter and the objective lens. The adapter for the aforesaid combination comprises a body member having a first coupling means at one end thereof to receive the objective lens and has a second coupling means at the other end thereof to receive the body tube. The body member has an axial light path running longitudinally therethrough and has a radial light path which intersects the axial light path. A source of light is disposed in the radial light path. A first filtering means is disposed in the radial light path, downstream of the source of light, for passing light at wavelengths which excite fluorescence in a specimen to be examined in the microscope and to remove light at wavelengths where visible fluorescence emission occurs in the specimen. A reflecting means is disposed in the intersection of the axial light path and radial light path. The reflecting means passes light through the axial light path and reflects light at excitation wavelengths, but does not reflect light at emission wavelengths. A second filtering means is disposed in the axial light path and is disposed between the reflecting means and the eye piece. The second filtering means blocks excitation wavelengths which pass through the reflecting means. The present invention is particularly useful as a relatively inexpensive means for detecting infectious diseases, such as tropical diseases and particularly malaria, which detection does not require the high resolution afforded by expensive fluorescent microscopes. Accordingly, in third world countries where the cost of fluorescent microscopes are prohibitive, the present invention would serve to provide medical personnel with a relatively inexpensive adapter which can be utilized in a conventional microscope in order to detect infectious diseases, such as malaria in a specimen of a patient. The invention can also be used to detect other blood borne parasites, for example, filariasis and heartworm in dogs. Still further, the invention can be employed in immunohistochemical procedures. By immunohistochemical is meant a procedure where an antibody, for example, is attached to a cell or tissue, and is tagged with a fluorescent moiety and the invention can be used to detect the point of attachment. One example of such procedure is to detect an anti-nuclear antibody which is tagged with fluorescein. BRIEF DESCRIPTION OF THE DRAWINGS For the purposes of illustrating the invention there is shown in the drawings forms which are presently preferred. It is to be understood, however, that the present invention is not limited to the precise arrangements and instrumentalities depicted in the drawings. Fig. 1 depicts a side elevational view of a conventional microscope wherein the inventive adapter can be employed. Fig. 2 is a side elevational view of a conventional microscope as depicted in Fig. 1 and having installed therein an adapter according to the present invention. Fig. 3 is an elevational view of a portion of the microscope and adapter as depicted in Fig. 2 and containing a partial cross-sectional view taken along line 3-3 in Fig. 2. Fig. 4 is an elevational view of a microscope adapter as depicted in Fig. 2 and Fig. 3 in a detached state from a turret and an objective lens of a microscope as depicted in Figs. 2 and 3. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings, in which like parts are designated by like reference numerals, Fig. 1 depicts a conventional microscope 10 in which an inventive adapter can be utilized, Microscope 10 has eye piece 12, turret 14, objective lens 16, objective lens 18 and specimen holder 20. A preferred microscope adapter 22 of the invention is depicted in Fig. 2. The adapter 22 is installed in a microscope 10 between objective lens 18 and turret 14. The adapter 22 is depicted in greated detail in Fig. 3. The light source for microscope adapter 22 includes a quartz-halogen lamp 24 and a condensing lens 26. Non-limiting examples of other lamps that can be employed are a vacuum tungsten lamp or a mercury lamp. Light from this source is filtered by an excitation filter 28 so as to pass light at wavelengths (for example, 490 nm and below) which excite fluorescence in the specimen to be examined, typically in the violet region, and to remove light at wavelengths (for example, 510 nm and above) where visible fluorescence emission occur in the specimen, typically green, yellow or red regions. The filtered excitation light is then reflected by a dichroic mirror 30 onto the objective lens 18 of the microscope, which focuses the excitation light onto the specimen. The dichroic mirror 30 reflects the majority of light (preferably reflects 80% and greater and more particularly, reflects 90% or greater) at the excitation wavelengths, but does not reflect light at emission wavelengths. A partially reflective mirror (beam splitter) could be used, but it is substantially less efficient. A beam splitter typically reflects and transmits about 50% of light. Fluorescent light emitted by the specimen is focused by the objective lens 18, and passes through the mirror 30 eventually to the eye piece (see item 12 in Fig. 2). An emission filter 32 which passes emission wavelengths and blocks excitation wavelengths is placed in the light path between the mirror 30 and the observer to block any reflections of the excitation beam from the specimen or the surrounding optics. It is convenient to place this emission filter 32 just above the dichroic mirror 30, i.e., the emission filter 32 is disposed between the dichroic mirror 30 and the eye piece of a microscope in which the adapter is installed. As depicted in Fig. 3, emission filter 32 is adjacent to screw threads 38. Screw threads 34 permit the adapter 22 to be screw thread connected to the screw threads 36 of the objective lens 18 of the microscope. Screw threads 38 of adapter 22 permit the adapter 22 to be screw thread connected to the screw threads 40 of the turret 14 of the microscope. Although screw threads are the preferred means to connect the adapter 22 to the microscope 10, it is to be understood that other mechanical coupling means can be employed, for example, friction fit coupling or bayonet coupling. It will be appreciated that the instant specification and claims are set forth by way of illustrtion and not limitation, and that various modifications and changes may be made without departing from the scope of the present invention.

Claims: An adapter (22) for supporting at least one objective lens (18) of a microscope (10) comprising: a body member having a first mounting means (34) at one end thereof and having a second mounting means (38) at the other end thereof to detachably mount a microscope component (14), said body member having an axial light path running longitudinally therethrough and having a radial light path which intersects the axial light path, a source of light (24, 26) disposed in the radial light path, a first filtering means (28) disposed in the radial light path, downstream of the source of light, for passing light at wavelenghts which excite fluorescence in a specimen to be examined in the microscope and to remove light at wavelengths where visible fluoroscence emission occurs in the specimen, a reflecting means (30) disposed in the intersection of the axial light path and radial light path, the reflecting means passing light through the axial light path and reflecting light at excitation wavelengths, but not reflecting light at emission wavelengths and a second filtering means (32) disposed in the axial light path and disposed above the reflecting means adjacent the second mounting means, the second filtering means blocking excitation wavelengths which pass through the reflecting means, said adapter being characterised in that said first mounting means is arranged for detachably mounting directly to an objective lens of the microscope. An adapter according to claim 1, wherein the first and second mounting means comprise screw threads. An adapter according to claim 1, wherein the light source comprises a quartz halogen lamp (24) and a condensing lens (26). An adapter according to claim 1, wherein the reflecting means is a dichroic mirror. An adapter according to claim 1, wherein the reflecting means is a partially reflective mirror. An adapter according to claim 1, wherein said first filtering means pass light at wavelengths of 490 nm and shorter and remove light at wavelengths of 510 nm and longer.

Inventors: RATHBONE RICHARD RODION, WARDLAW STEPHEN CLARK, RATHBONE, RICHARD RODION, WARDLAW, STEPHEN CLARK
Applicants: UNIV YALE, YALE UNIVERSITY
Application year: 1990
Main classification: G02B21
IPC codes: G02B21