WO2012137212A2

WO2012137212A2 - Portable microscope

Info

Publication number: WO2012137212A2
Application number: PCT/IL2012/050131
Authority: WO
Inventors: Yuval GOREN
Original assignee: Ramot At Tel-Aviv University Ltd.
Priority date: 2011-04-06
Filing date: 2012-04-05
Publication date: 2012-10-11
Also published as: IL212169A0; IL212169A; WO2012137212A3

Abstract

According to one broad aspect of the invention, there is provided a microscope comprising a base, an imaging unit, and a polarizer device. The base carries a sample holding unit mounted on said base and defining an illumination path. The imaging unit is spaced apart from the sample holding unit along an imaging path. The sample holding unit comprises a housing carrying a light source for producing input light, a sample support member, condensing optics in the illumination path between the light source and the sample support member. The condensing optics comprises first and second condensing lens assemblies arranged in a spaced apart relationship along the illumination path. The polarizer device comprises an analyzer unit located in the illumination path between said first and second condensing lens assemblies, and a polarizer element located in the imaging unit.

Description

PORTABLE MICROSCOPE

FIELD OF THE INVENTION

This invention relates to optical microscopes, in particular to portable microscopes for use in the field.

BACKGROUND OF THE INVENTION

Microscopes are used for examination of samples in many fields, such as medicine, archeology, geology, and criminal investigations. At times, a necessity arises for examining samples in the field, as the time and/or an option may not be afforded for transporting collected samples to a laboratory. Such a necessity may be felt, for example, by medical personnel in field hospitals, by archeologists in archaeological excavation sites or museums, and by detectives at the crime scene. Light and portable microscopes have been therefore developed for use in the field.

One of the most popular portable microscopes is the McArthur microscope, a transmission-mode optical microscope which achieves its compactness by folding the optical path. Sample illumination is provided by using a traditional simple mirror and/or an integral light source powered by two AA batteries and featuring a halogen or LED bulb. The light travels downward and passes through a sample-carrying slide mounted on a stage, then on through one of the objectives, deflected by two mirrors or prisms in the optical light tube and finally upwards through the ocular. Three objectives are mounted on a sliding plate or turret under the stage and are currently available in magnifications of 10X, 40X, and 100X. Coupled with the standard 10X ocular, this provides total magnifications of 100X, 400X, and 1000X. An optional 5X ocular can be used to extend this range to include 50X, 200X, and 500X magnifications. The unit is focused with knurled knobs situated on either side of the housing. A variation of the above-described McArthur microscope, designed specifically for petrographic sample analysis, is disclosed in the following publication: Graham Chandler, "New applications of archaeological microscopy in the field: ceramic petrography and microwear analysis" (Papers from the Institute of Archaeology 5(1994) pp. 39-48). The microscope described in this publication utilizes a polarizer added into the filter slot on the condenser arm of the McArthur microscope, and an analyzer (a second polarizing filter) fixed to the base of the ocular drawtube. Crossed polars (XPL) are achieved by rotating the ocular drawtube, with the polarizer and no sample in place, until the transmitted light intensity is at its lowest. A rotating stage for holding the sample is mounted on the condenser housing and secured in place with two set screws. A final modification is the installation of an eyepiece graticule into the ocular, for measuring grain size and area.

US Patent Application 2004/0066553 to Gilbert discloses a portable microscope comprising a stand that carries an adjustable-height microscope stage. The microscope stage is constructed from a sample support part, a guide part, and a base which carries an illumination module.

GENERAL DESCRIPTION

There is a need for a portable microscope that would be desirably compact while maintaining the high-quality imaging. The invention provides a novel portable-type optical microscope, in which the space occupied by a focusing mechanism is decreased as compared to the conventional approach, thus enabling decrease of the size of the microscope. Furthermore, the microscope of the present invention offers the same advantages as a laboratory bench model, i.e., a portable microscope designed for being usable without straining a user's back or eye and for replacing a laboratory bench model in ceramic petrography, micromorphology, microwear analysis and forensic studies.

In a variant, the imaging unit comprises at least one objective lens assembly for collecting light resulting from interaction of the input light with a sample and propagating along the imaging path, and an eyepiece configured for enabling user's eye location in the imaging path.

The polarizer element may be located between the objective lens assembly and the eyepiece.

In another variant, the first condensing lens assembly is located in the vicinity of the light source while the second condensing lens assembly is located in the vicinity of a sample plane. The second condensing lens assembly may be incorporated in the sample support member.

In a further variant, the sample support is located at a certain fixed distance from the light source along the illumination path.

In yet another variant, the housing is shiftable between its folded and extended positions with respect to said base, to thereby cause movement of the sample holding unit with respect to the imaging unit. Optionally, said housing is a two-part device, one part being fixed on said base, and the other part associated with said sample holding unit and being movably mounted on said first part, movement of said second part with respect to said first part implementing said shift between the folded and extended positions of the housing with respect to said base.

In yet a further variant, said imaging unit comprises a plurality of objective lens assemblies configured for providing different image magnifications respectively, the imaging unit being configured for selectively locating one of the objective lens assemblies in the imaging path. Optionally, the imaging unit comprises a carousel-like turret arrangement comprising said plurality of objective lens assemblies accommodated in a spaced-apart relationship along a circular path, rotation of said carousel-like turret arrangement in a plane substantially perpendicular to the imaging path resulting in selectively locating one of the objective lens assemblies in the imaging path.

In a variant, the eyepiece comprises two oculars for providing a binocular view of the sample.

According to some embodiments of the present invention, the sample support member is configured for being movable with respect to said housing in a plane substantially perpendicular to the illumination path.

In a variant, the imaging unit comprises a Bertrand lens located in the imaging path between the objective lens assembly and the eyepiece.

In another variant, said analyzer unit comprises a plate-like member having at least two spaced-apart sites differently affecting polarization of light passing therethrough, said plate -like member being mounted for sliding movement in a plane substantially perpendicular to the illumination path thereby enabling selectively locating a respective one of said sites in the illumination path. Optionally, the plate-like member comprises three different polarization affecting sites, each constituted by a respective optical window made in said plate-like member, a first optical window being configured for substantially not affecting polarization of light passing therethrough, a second optical window comprising a first polarizer sheet, and a third optical window comprising a second polarizer sheet and a polarization rotator element.

The above microscope may be configured as a transmission-mode microscope or as a fluorescent-mode microscope.

The above microscope may be configured as a portable microscope.

Optionally, said first and second parts are configured to movably engage one another via a screwing mechanism between said first part and said second part, said screwing mechanism causing ascending and descending of said second part with respect to said first part upon rotation of said second part, to thereby drive movement of the sample holding unit with respect to the imaging unit.

According to another aspect of some embodiments of the present invention, there is provided a microscope comprising a base and an imaging unit. The base carries a sample holding unit mounted on said base and defining an illumination path. The imaging unit is spaced apart from the sample holding unit along an imaging path. The sample holding unit comprises a housing carrying a light source for producing input light and a sample support member located at a certain fixed distance from the light source along the illumination path. The housing comprises a fixed portion attached to said base and a rotatable portion containing said sample holding unit and being movably mounted on said fixed portion, thereby providing a screwing mechanism between said fixed portion and said rotatable portion, said screwing mechanism causing an ascending and descending motion of said rotatable portion with respect to said fixed portion upon rotation of said rotatable portion, to thereby cause movement of the sample holding unit with respect to the imaging unit. The imaging unit comprises at least one objective lens assembly for collecting light resulting from interaction of the input light with a sample and propagating along the imaging path, and an eyepiece configured for enabling user's eye location in the imaging path.

In a variant, the rotatable portion comprises a proximal section and a distal section. The proximal section movably mounted on said fixed portion. The distal section mounted on said proximal section, such that proximal section's ascending and descending motion causes ascending and descending motion of said distal section, while said rotation of said proximal section does not cause rotation of said distal section.

In a variant, the imaging unit comprises a plurality of objective lens assemblies configured for providing different image magnifications respectively, the imaging unit being configured for selectively locating one of the objective lens assemblies in the imaging path. Optionally, the imaging unit comprises a carousel-like turret arrangement comprising said plurality of objective lens assemblies accommodated in a spaced-apart relationship along a circular path, rotation of said carousel-like turret arrangement in a plane substantially perpendicular to the imaging path resulting in selectively locating one of the objective lens assemblies in the imaging path.

In another variant, the eyepiece comprises two oculars for providing a binocular view of the sample.

In a further variant, the sample support member is configured for being movable with respect to said housing in a plane substantially perpendicular to the illumination path. Optionally, the sample support member is configured for being rotatable with respect to said housing in a plane substantially perpendicular to the illumination path. In yet another variant, the sample holding unit comprises condensing optics located in said housing in the illumination path. Optionally, the condensing optics comprises first and second condensing lens assemblies arranged in a spaced apart relationship along the illumination path. The first condensing lens assembly may be located in the vicinity of the light source, while the second condensing lens assembly may be located in the vicinity of a sample plane. The second condensing lens assembly may be incorporated in the sample support member.

In yet a further variant, the above microscope comprises a polarizer device comprising an analyzer unit located in the sample holding unit between said first and second condensing lens assemblies, and a polarizer located in said imaging unit.

The microscope may comprise a polarizer device comprising an analyzer unit located in the sample holding unit in the illumination path, and a polarizer located in said imaging unit in the imaging path.

According to some embodiments of the present invention, the imaging unit comprises a Bertrand lens located in the imaging path between said at least one objective lens assembly and said eyepiece.

The analyzer unit may comprise a plate-like member having at least two spaced- apart sites differently affecting polarization of light passing therethrough, said plate-like member being mounted for sliding movement in a plane substantially perpendicular to the illumination path thereby enabling selectively locating a respective one of said sites in the illumination path.

Optionally, the plate-like member comprises three different polarization affecting sites, each constituted by a respective optical window made in said plate-like member, a first optical window being configured for substantially not affecting polarization of light passing therethrough, a second optical window comprising a first polarizer sheet, and a third optical window comprising a second polarizer sheet and a polarization rotator element..

The above microscope may be configured as a transmission-mode microscope, or as a fluorescent-mode microscope.

The above microscope may be configured as a portable microscope.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

Figs, la-lb are schematic illustrations of a microscope of the present invention having a housing operable for being telescopically contracted (Fig. la) and extended (Fig. lb);

Figs. 2a-2b are schematic drawings illustrating an embodiment of the present invention, in which the housing contracts (Fig. 2a) and extends (Fig. 2b) by screwing a rotatable portion having a threaded cylindrical outer surface over a fixed portion;

Figs. 3a-3b are schematic drawings illustrating an embodiment of the present invention, in which the housing contracts (Fig. 3a) and extends (Fig. 3b) by screwing a rotatable portion over a fixed portion having a threaded cylindrical outer surface;

Figs. 4a-4b are drawings illustrating an embodiment of the present invention in which the housing is configured like a focus ring of a single lens reflex (SLR) camera, having a first portion fixed to the base, and a second portion joined to the first portion in a screw mechanism;

Figs. 5a-5b are schematic drawings illustrating an embodiment of the present invention, in which the housing contracts (Fig. 5a) and extends (Fig. 5b) by sliding a movable portion along an inner surface of a fixed portion;

Figs. 6a-6b are schematic drawings illustrating an embodiment of the present invention, in which the housing contracts (Fig. 6a) and extends (Fig. 6b) by sliding a movable portion along an outer surface of a fixed portion;

Fig. 7 is a schematic drawing exemplifying a (portable) microscope of the invention having polarizing optics;

Fig. 8 is a cross-sectional view of the housing of a microscope of the present invention, in which an analyzer includes a sliding plate having three locations and designed for being translated by user so that the desired location is within the optical path originating from a light source; and

Fig. 9 is an isometric illustration of the analyzer of Fig. 8.

DETAILED DESCRIPTION OF EMBODIMENTS

Referring to Figs, la-lb there is schematically illustrated an example of a (portable) microscope 100 of the present invention in its two different positions respectively. The microscope 100 includes a base 102, a sample holding unit 104 mounted on the base 102, and an imaging unit 106.

The sample holding unit 104 includes a housing 108 carrying a support member

(e.g. stage) 112 on which a sample 114 can be placed and a light source 110 maintained at a certain distance from the sample support 112. The support member 112 defines an optical window 116 (e.g. has a transparent portion 116 or is entirely transparent thus presenting an optical window) allowing access of light from the light source to the sample. It should be noted that the support member is sometimes referred to below as "stage", although it should be understood that such a stage may or may not be movable with respect to the housing, and if movable this may be linear movement along z-axis (optical axis) and/or in the x-y-plane (sample's plane), as well as rotation in the x-y- plane. The sample holding unit 104 thus defines an illumination channel of a certain illumination path (an optical path between the light source and the stage). The sample holding unit 104 is configured and operable for movement with respect to the imaging unit. To this end, the housing 108 is configured as a telescopically extending/contracting device shiftable between its contracted position (Fig. la) and extended position (Fig. lb) moving the stage together with the light source upwards and downwards with the respect to the imaging unit 106. In this manner, during the extension and contraction of the housing 108, an illumination path (an optical path between the light source and the stage) is kept unchanged while an imaging path (an optical path between the stage and the imaging unit) varies.

The imaging unit 106 includes an objective lens assembly 118 (at least one lens) and an eyepiece 120 located in the illumination path. The extension/contraction of the housing 108 moves the stage 112 (and thus the sample 114 located thereon) closer to/farther from the objective 118, and thus allows for adjusting the focus of the microscope 100. As will be seen later, the extension/contraction of the housing 108 may be preferably performed via rotation of a screw mechanism (as seen in Figs. 2a-3b), or via a sliding mechanism (as seen in Figs. 4a-5b).

The above configuration of the microscope 100 enables it to be of a desirably small size. The provision of telescopically extendable/contractible housing eliminates a need for a space-demanding mechanism such as the "rack and pinion" or "Z-drive". Furthermore, the housing 108 is fixed to the base 102, therefore eliminating or at least reducing a need for any balancing mechanism in the microscope 100.

As indicative above, the imaging unit 105 includes the objective lens assembly

118. This may be a single-objective assembly, namely an assembly formed by one or more lenses operable together as an imaging lens unit. Alternatively, the assembly 119 may include multiple different objective assemblies (each formed by one or more lenses and providing different magnification), and configured so as to selectively locate a desired one of the assemblies in the imaging path. This may for example be a carousellike member (a turret) carrying an array of objective assemblies arranged in a spaced- apart relationship along a circular path. In this manner a selectable magnification is provided. The eyepiece 120 may be a binocular eyepiece (i.e., including two oculars), for decreasing the user's eye strain. Optionally, the eyepiece 120 includes an eye cup (not pictured), for further decreasing the user's eye strain.

In the present example, the microscope is configured as a transmission-mode or fluorescent-mode microscope, i.e., light propagating from the sample along the imaging path is either light transmitted through the sample 114 or light emitted from the sample in response to excitation by the illumination. It should be noted, although not specifically shown, that the principles of the invention can be implemented in a reflection mode microscope, and can be used in an epi-illuminated (reflected light) microscope for metallography or the examination of other opaque specimens.

It should also be noted that the stage 112 may be movable within a sample plane (x-y plane) with respect to the illumination and imaging paths while being at a fixed distance from the light source (fixed location along z-axis). For example, the stage may be mounted for linear movement or for rotation with respect to the housing 108. The light source 110 may be of any suitable type, e.g. LED-based. In a variant, the light source 110 is powered by a battery located, for example, in the base 102. Alternatively or additionally, the microscope 100 includes a connection port for connecting the light source 110 to an external power source, e.g. for charging the battery. For example, the microscope may be connectable to a computer (a laptop computer, for example) via its USB port.

The microscope 100 may further include optical elements, such as condensing optics located in the illumination path between the light source 110 and the stage 112, and/or polarizing optics (a polarizer/analyzer setup), and/or a Bertrand lens. As will be described further below with reference to Fig. 6, in some embodiments of the present invention, the condensing optics and polarizer/analyzer setup are used being arranged in a space-saving configuration.

Reference is made to Figs. 2a-2b, 3a-3b, 4a-4b, 5a-5b and 6a-6b showing schematically some specific but not limiting examples of a telescopic mechanism suitable to be used in the microscope of the present invention.

In the example of Figs. 2a-2b, the housing 108 is shiftable between folded position (Fig. 2a) and extended position (Fig. 2b) by screwing a rotatable portion having a threaded cylindrical outer surface over a fixed portion. The rotation of the screwing is a so-called "horizontal rotation" performed within the x-y plane (the sample's plane), and causes a so-called "vertical motion" (reciprocating motion) of the rotatable portion along the z-axis (the optical axis, i.e. the main axis of the illumination path). The housing 108 includes first and second cylindrical portions: a first fixed portion 200 attached to the base 102, and a rotatable portion 202 mounted for rotation with respect to the portion 200. The first portion 200 has a threaded inner surface 204, and the second portion 202 has outer surface sporting threads 206 matching the threaded inner surface 204 of portion 200. The rotation of portion 202 causes it to ascend or descend with respect to portion 200 via the screw mechanism. The light source (110 in Figs, la-lb) is housed within the rotatable portion 202, and therefore moves along the vertical axis (z-axis) together with the rotatable portion 202. The stage 112 is attached to the rotatable portion 202, and therefore also moves along the z-axis together with the rotatable portion 202. In a non-limiting example, the housing 108 is configured like a focus ring of a single lens reflex (SLR) camera, having a first portion fixed to the base 102, and a second rotatable portion joined to the first portion in a screw mechanism. The inventor has constructed a working model of the microscope 100 using the focus ring of a Zenza 5 Bronica 60 mm SLR camera as the housing 108 of the sample holding unit.

In the example of Figs. 3a-3b the housing is shiftable between its folded position (Fig. 3a) and extended position (Fig. 3b) by screwing a rotatable portion over a fixed portion having a threaded cylindrical outer surface. The housing 108 includes a first fixed portion 300 attached to the base 102 and a rotatable portion 302. The latter

10 houses the light source 100 and the stage 112 at a fixed distance between them. The fixed portion 300 has a threaded cylindrical outer surface surrounded by a threaded inner surface of the rotatable portion 302, such that the fixed portion 300 and the rotatable portion 302 give rise to a screw mechanism. Horizontal rotation of the rotatable portion 302 with respect to the fixed portion 300 causes the rotatable portion

15 302 to move (vertically) along the z-axis.

In the example of Figs. 4a and 4b the housing 108 is configured like a focus ring of a single lens reflex (SLR) camera, having a first portion fixed to the base, and a second portion joined to the first portion in a screw mechanism. In Fig. 4a, the housing 108 and the support member 112 are shown. In Fig. 4b, an exploded view of the 20 housing 108 is illustrated.

The first portion 200 of the housing 108 is a hollow cylinder fixed to the base 102. The inner surface 204 of the hollow cylinder is threaded. The second portion 202 has an outer surface sporting threads 206 matching the threaded inner surface 204 of first portion 200 to thereby engage with the first portion. The second portion 202

25 comprises two sections: a proximal section 202a (in proximity with the first portion

200), and a distal section 202b, which supports / connected to the sample support member 112. The proximal section 202a of the second portion 202 houses at least the light source 110 and is rotatable with respect to the first portion 200, such that a screwing mechanism is provided (due to the matching threads as described above) for

30 moving the proximal section 202a along the optical axis (z-axis) upon rotation of the proximal section 202a within the sample's plane (x-y plane). The distal section 202b is joined to the proximal section via additional threads 250. This manner of connection ensures that while the distal section 202b moves along the z-axis together with the proximal section 202a, the distal section 202b does not follow the rotation of the proximal section 202a. In this manner, the support member 112 (which is joined to the distal section 202b) can be moved along the optical axis, but does not rotate with the proximal section 202a of the housing 118 (i.e. the rotation of the proximal section of the second portion drives the linear movement of the support member connected to the distal section of the second portion). As explained above, an independent mechanism may be present to enable linear movement and/or rotation of the support member 112 with respect to the housing 108.

As shown in the figures, two condenser lenses are provided arranged along the optical axis in a spaced-apart relationship. Both of them may be located in the proximal section of the second portion. As shown in the specific but not limiting example of Fig. 4a, one of the lenses is located in the proximal section, while the other lens is integral / carried by the sample support member. As a way of example, as shown in Fig. 4a, the proximal section 202a houses a first condensing lens 610, while the optical window of the support member 112 surrounds a second condensing lens 612, and an analyzer 620 is located below the support member 112, between the first and second condensing lenses. Such optical elements and their positions relative to each other are described in detail below, with reference to Figs. 7-9.

In the example of Figs. 5a-5b, the housing 108 moves between its folded positions (Fig. 5a) and extended positions (Fig. 5b) by sliding a movable portion along an inner surface of a fixed portion. The housing 108 includes a first fixed portion 400 attached to the base 102 and a slidable portion 402 which houses the light source 100 and the stage 112 at a fixed distance between them. The fixed portion 400 is coupled to the outer surface of the slidable portion 402, such that the slidable portion 402 can be slid vertically along the fixed portion 400. A pressure is applied by the fixed portion to the 400 slidable portion 402, in order to enable the slidable portion 402 to remain at a selected height without being held by the user. For example, the fixed portion 400 has an inner surface in physical contact with the outer surface of the slidable portion 402, such that a degree of coupling between these surfaces varies by the applied pressure to the outer surface of the slidable portion 402. Figs.6a-6b shows a similar example, where the housing is shiftable between a folded position (Fig.6a) and an extended position (Fig.6b) by sliding a movable portion along an outer surface of a fixed portion. The housing 108 includes a fixed portion 500 attached to the base 102 and a slidable portion 502 which houses the light 5 source 100 and the stage 112 at a fixed distance between them. The slidable portion 502 is designed for sliding along an outer surface of the fixed portion 500. For example, the fixed portion 500 is surrounded by and is in physical contact with the slidable portion 502.

Reference is now made to Fig.7 schematically illustrating an example of a 10 portable microscope 600 of the invention having polarizing optics. The microscope 600 is generally similar to the above-described microscope 100 of Figs la-lb, while in the microscope 600 a change in the optical path length may or may not implemented using a telescopic mechanism.

The microscope 600 includes a sample holding unit 604 carried by a housing

15 608 mounted on a base 102, and an imaging unit 106. The sample holding unit 604 includes a light source 110 and a stage 112 for supporting a sample 114 at a fixed distance (along z-axis from the light source. Also provided in the sample holding unit 604 is a condensing optics located in the illumination path for condensing light propagating towards the sample 114. The condensing optics is configured as an Abbe

20 condenser, and includes a first condensing lens assembly 610 (at least one lens) located closer to the light source 110 and a second condensing lens assembly 612 (at least one lens) located closer to the stage 112. The first condensing lens assembly 610 partially condenses light produced by the light source, and the second condensing lens assembly 612 further condenses the light, so that light 618 reaching the sample 114 is fully

25 condensed. The Abbe condenser provides conoscopic light and is useful for improving brightness, evenness of illumination, and contrast, which are parameters that are particularly important for magnifications of above 400X. The second condensing lens assembly 612 may be installed within the stage (e.g. in the optical window 116), thus fixing the second condensing lens 612 at a suitable distance from the first condensing

30 lens while eliminating a need for additional support mechanism.

Polarizing optics is provided including a polarizer 624 located in the imaging unit 106 (i.e. in the imaging path), and an analyzer 620 located in the sample holding unit 604. The analyzer 620 is placed in the illumination path, between the first condensing lens assembly 612 and the second condensing lens assembly 614. This is contrary to the conventional approach used in microscopes (such as bench models and the Chandler microscope), according to which the analyzer is placed in the imaging 5 path. The inventor has found that using a two-part condenser (two condensing lens assemblies spatially separated along the illumination path) allows for placing the analyzer 620 in the illumination path between the two condensing lens assemblies thus reducing the entire optical path length and accordingly the size of the microscope. Placing the analyzer 620 between the first and second condensing lenses (612 and 614) 10 reduces the size of the sample support unit 604, since the condensing optics and the analyzer occupy the same space, and are not set one after the other.

Thus, light 614 produced by the light source 110 is partially condensed by lens assembly 610, partially condensed light 622 passes through analyzer 620, and so- produced polarized light 616 is further condensed by lens assembly 612 just prior to

15 reaching the sample 114. Light 626 resulting from interaction with the sample 114 (transmitted through the sample or emitted by the sample, as the case may be) propagates along imaging path to imaging channel defined by the imaging unit 106. Here, light 626 is collected by objective lens assembly 118 towards the polarizer 624, and output light propagates to the eyepiece 120. In the present example, the polarizer

20 624 is located near the objective 118, downstream thereof (with respect to general light propagation through the microscope). It should however be noted that generally the polarizer 624 may be located anywhere in the imaging path (i.e. between the sample 114 and the eyepiece). Also, in the present example, the imaging unit includes a light directing optics 630 for directing polarized light 628 from the polarizer 624 toward the

25 ocular 120. Such light directing optics 630 may include a prism.

It should be noted, although not specifically shown, that the imaging unit 106 may include a Bertrand lens for performing interference analysis on the sample 114. The Bertrand lens may for example be integral with light directing optics 630, e.g. may be incorporated in the prism. Optionally, the Bertrand lens is removable from the 30 imaging unit 106 and/or displaceable with respect to the imaging path to be selective in or outside thereof. The presence of the Bertrand lens enables advanced analysis of crystals or crystalline material. In particular, it enables a user to distinguish between symmetrical crystalline structures and non-symmetrical crystalline structures.

An experimental microscope set up created by the inventor included all the above-described elements, and also Bertrand lens and a battery. Such microscope has a width of about 18 centimeters, a height of about 27 centimeters, and mass of about 2 kilograms.

As indicated above, in the microscope 600, similar to the above-described microscope 100, the housing 608 may be configured for providing movement of the sample holding unit along the z-axis with respect to the imaging unit, as described above, with reference to the housing 108 of Figs, la through 6b.

Referring to Figs. 8 and 9, there is illustrated an example of the analyzer according to the invention suitable to be used in a polarized microscope, in particular a portable microscope, e.g. that of the example of Fig. 7. Fig. 8 shows a cross-sectional view of the housing containing the analyzer, and Fig. 9 shows a perspective view of the analyzer. In this example, the analyzer 620 is configured as a plate (sliding plate) having three spaced-apart sites each configured for differently affecting polarization of light passing therethrough (interacting therewith). By moving (sliding) the plate in a plane (x-y plane) perpendicular to the illumination path (z-axis), a selected one of the polarizing assemblies can be placed in the illumination path. For example, the plate 700 can be insertable into a slot appropriately provide in the housing 608 and translatable along said slot, such that light incident onto the plate 700 (e.g. light partially condensed by the first condenser 610) passes through (interacts with) a respective one of three sites of the plate located in the optical path. Optionally, the slot receiving the sliding plate 700 is located at the end of the housing 608 close to the support member 112. In a variant, the analyzer 620 includes a handle 710 on one of both ends of the sliding plate 700, for comfortable handling of the analyzer 620.

According to some embodiments of the present invention, the analyzer 620 includes an opaque plate 700 having three sites in the form of three openings or generally optical windows. The first optical window 702 does not affect light passing therethrough (e.g. enables the partially condensed light to pass unaffected through the analyzer 620). The second optical window (opening) is covered by a first polarizer sheet 704 configured for polarizing light passing therethrough. The third optical window (opening) is covered by a second polarizer sheet 706 and a polarization rotator (wave plate) 708, for polarizing and rotating the polarization of light propagating therethrough. The analyzer 620 may have optical windows 702, 704, and 706 set in an order different than the order depicted in Figs. 6 and 7.

Claims

CLAIMS:

1. A microscope comprising:

a base carrying a sample holding unit mounted on said base and defining an illumination path; an imaging unit spaced apart from the sample holding unit along an imaging path; and a polarizer device, wherein

the sample holding unit comprises a housing carrying a light source for producing input light, a sample support member, condensing optics in the illumination path between the light source and the sample support member,

said condensing optics comprises first and second condensing lens assemblies arranged in a spaced apart relationship along the illumination path;

the polarizer device comprises an analyzer unit located in the illumination path between said first and second condensing lens assemblies, and a polarizer element located in the imaging unit.

2. The microscope of claim 1, wherein the imaging unit comprises at least one objective lens assembly for collecting light resulting from interaction of the input light with a sample and propagating along the imaging path, and an eyepiece configured for enabling user's eye location in the imaging path.

3. The microscope of claim 2, wherein the polarizer element is located between the objective lens assembly and the eyepiece.

4. The microscope of any one of claims 1 to 3, wherein the first condensing lens assembly is located in the vicinity of the light source; and the second condensing lens assembly is located in the vicinity of a sample plane.

5. The microscope of claim 4, wherein said second condensing lens assembly is incorporated in the sample support member.

6. The microscope of any one of claims 1 to 5, wherein the sample support is located at a certain fixed distance from the light source along the illumination path.

7. The microscope of any one of claims 1 to 6, wherein said housing is shiftable between its folded and extended positions with respect to said base, to thereby cause movement of the sample holding unit with respect to the imaging unit.

8. The microscope of claim 7, wherein said housing is a two-part device, one part being fixed on said base, and the other part associated with said sample holding unit and being movably mounted on said first part, movement of said second part with respect to said first part implementing said shift between the folded and extended positions of the housing with respect to said base.

9. The microscope of any one of claims 1 to 8, wherein said imaging unit comprises a plurality of objective lens assemblies configured for providing different image magnifications respectively, the imaging unit being configured for selectively locating one of the objective lens assemblies in the imaging path.

10. The microscope of claim 9, wherein the imaging unit comprises a carousel-like turret arrangement comprising said plurality of objective lens assemblies accommodated in a spaced-apart relationship along a circular path, rotation of said carousel-like turret arrangement in a plane substantially perpendicular to the imaging path resulting in selectively locating one of the objective lens assemblies in the imaging path.

11. The microscope of any of claims 1 to 10, wherein said eyepiece comprises two oculars for providing a binocular view of the sample.

12. The microscope of any one of claims 1 to 11, wherein said sample support member is configured for being movable with respect to said housing in a plane substantially perpendicular to the illumination path.

13. The microscope of any one of claims 1 to 12, wherein the imaging unit comprises a Bertrand lens located in the imaging path between the objective lens assembly and the eyepiece.

14. The microscope of any one of claims 1 or 13, wherein said analyzer unit comprises a plate-like member having at least two spaced-apart sites differently affecting polarization of light passing therethrough, said plate-like member being mounted for sliding movement in a plane substantially perpendicular to the illumination path thereby enabling selectively locating a respective one of said sites in the illumination path.

15. The microscope of claim 14, wherein the plate-like member comprises three different polarization affecting sites, each constituted by a respective optical window made in said plate-like member, a first optical window being configured for substantially not affecting polarization of light passing therethrough, a second optical window comprising a first polarizer sheet, and a third optical window comprising a second polarizer sheet and a polarization rotator element.

16. The microscope of any one of claims 1 to 15, being configured as a transmission-mode microscope.

17. The microscope of any one of claims 1 to 15, being configured as a fluorescent-mode microscope.

18. The microscope of any one of claims 1 to 17, configured as a portable microscope.

19. The microscope of any one of claims 8 to 18, wherein said first and second parts are configured to movably engage one another via a screwing mechanism between said first part and said second part, said screwing mechanism causing ascending and descending of said second part with respect to said first part upon rotation of said second part, to thereby drive movement of the sample holding unit with respect to the imaging unit.

20. A microscope comprising:

a base carrying a sample holding unit mounted on said base and defining an illumination path; and an imaging unit spaced apart from the sample holding unit along an imaging path, wherein

the sample holding unit comprises a housing carrying a light source for producing input light and a sample support member located at a certain fixed distance from the light source along the illumination path;

said housing comprises a fixed portion attached to said base and a rotatable portion containing said sample holding unit and being movably mounted on said fixed portion, thereby providing a screwing mechanism between said fixed portion and said rotatable portion, said screwing mechanism causing an ascending and descending motion of said rotatable portion with respect to said fixed portion upon rotation of said rotatable portion, to thereby cause movement of the sample holding unit with respect to the imaging unit;

the imaging unit comprises at least one objective lens assembly for collecting light resulting from interaction of the input light with a sample and propagating along the imaging path, and an eyepiece configured for enabling user's eye location in the imaging path.

21. The microscope of claim 1, wherein said rotatable portion comprises: a proximal section movably mounted on said fixed portion; and

a distal section mounted on said proximal section, such that proximal section's ascending and descending motion causes ascending and descending motion of said distal section, while said rotation of said proximal section does not cause rotation of said distal section.

22. The microscope of claim 20 or 21, wherein said imaging unit comprises a plurality of objective lens assemblies configured for providing different image magnifications respectively, the imaging unit being configured for selectively locating one of the objective lens assemblies in the imaging path.

23. The microscope of claim 22, wherein the imaging unit comprises a carousel-like turret arrangement comprising said plurality of objective lens assemblies accommodated in a spaced-apart relationship along a circular path, rotation of said carousel-like turret arrangement in a plane substantially perpendicular to the imaging path resulting in selectively locating one of the objective lens assemblies in the imaging path.

24. The microscope of any of claims 20 to 23, wherein said eyepiece comprises two oculars for providing a binocular view of the sample.

25. The microscope of any one of claims 20 to 24, wherein said sample support member is configured for being movable with respect to said housing in a plane substantially perpendicular to the illumination path.

26. The microscope of claim 25, wherein said sample support member is configured for being rotatable with respect to said housing in a plane substantially perpendicular to the illumination path.

27. The microscope of any one of claims 20 to 26, wherein the sample holding unit comprises condensing optics located in said housing in the illumination path.

28. The microscope of claim 27, wherein said condensing optics comprises first and second condensing lens assemblies arranged in a spaced apart relationship along the illumination path.

29. The microscope of claim 28, wherein the first condensing lens assembly is located in the vicinity of the light source; and the second condensing lens assembly is located in the vicinity of a sample plane.

30. The microscope of claim 29, wherein said second condensing lens assembly is incorporated in the sample support member.

31. The microscope of any one of claims 28 to 30, comprising a polarizer device comprising an analyzer unit located in the sample holding unit between said first and second condensing lens assemblies, and a polarizer located in said imaging unit.

32. The microscope of any one of Claims 20 to 31 comprising a polarizer device comprising an analyzer unit located in the sample holding unit in the illumination path, and a polarizer located in said imaging unit in the imaging path.

33. The microscope of any one of claims 20 to 32, wherein the imaging unit comprises a Bertrand lens located in the imaging path between said at least one objective lens assembly and said eyepiece.

34. The microscope of claim 31 or 32, wherein said analyzer unit comprises a plate-like member having at least two spaced-apart sites differently affecting polarization of light passing therethrough, said plate-like member being mounted for sliding movement in a plane substantially perpendicular to the illumination path thereby enabling selectively locating a respective one of said sites in the illumination path.

35. The microscope of claim 34, wherein plate-like member comprises three different polarization affecting sites, each constituted by a respective optical window made in said plate-like member, a first optical window being configured for substantially not affecting polarization of light passing therethrough, a second optical window comprising a first polarizer sheet, and a third optical window comprising a second polarizer sheet and a polarization rotator element..

36. The microscope of any one of claims 20 to 35, being configured as a transmission-mode microscope.

37. The microscope of any one of claims 20 to 35, being configured as a fluorescent-mode microscope.

38. The microscope of any one of claims 20 to 37, configured as a portable microscope.