Technical Field

The present invention relates to microscope apparatus and components for microscope apparatus. The preferred embodiments provide apparatus and components that allow the analysis of multiple samples in an automated process.

Background of the Invention

The analysis of samples by microscopes is a long established art. In more recent times there has been a need to analyse a multitude of samples in a sequential process, for instance in the investigation of diseases, illnesses, biological specimens, industrial hygiene specimens, and so on. For such purposes there have been developed microscope systems that are able to hold and feed to the optical unit of a microscope multiple slides sequentially for sequential analysis of samples on the slides. In a typical system of such a type, there is provided a slide holder comprising a plurality of slide supports configured to hold slides in a generally horizontal orientation , and a mechanism to feed individual slides from the holder to the microscope.

Slide dispensers tend to fall into two categories: (a) lateral slide dispensers, and (b) rotary slide dispensers.

In a lateral slide dispenser, the slides are brought onto a stage using a robotic arm of some sort, set in place. The stage moves the slide along the three orthogonal axes as known. This solution is expensive, slow (each slide needs to be put in place precisely), and takes a large amount of volume around the microscope.

In a rotary slide dispenser, the slides are mounted on a mechanism that is fixed in space: basically a rotating part, which is itself further moved in three orthogonal directions. In this version, there is no loading tray and one attaches the slides by the small edge outside of the microscope measurement area. This mechanism is cumbersome and does not allow for slide preparation in a separate environment or place. Additionally, the nature of the design makes it extremely sensitive to vibrations, which hampers the resolution of the microscope particularly at magnifications equal or larger than 40x.

Systems of such nature are able to process large numbers of slides in a single automated process. However, such systems tend to be very expensive to operate and require complex mechanisms and methods to load slides into the holders. As a consequence, such systems tend to be of limited commercial appeal.

There is also a growing need for more precise and repeatable analysis of samples by microscope, as well as more in-depth analysis. While this can in theory be achieved by careful and individual control of the microscope optics by a user, this is not suitable for larger scale and sequential testing of large numbers of samples.

Examples of systems for handling a multitude of slides are disclosed, for example, in US-2019/101553, EP-0,896,238, EP-0,308,151 , US-2018/059395.

Summary of the Invention

The present invention seeks to provide improved microscope apparatus and improved components therefor. The preferred embodiments seek to provide apparatus and devices that allow the analysis of multiple samples in an automated process, and in which a multitude of slides and can efficiently fed to a microscope and, or in the alternative, analysed very precisely and reliably.

According to an aspect of the present invention, there is provided microscope apparatus including: a microscope body comprising at least one microscope optical element; a frame having at least one support surface and a viewing aperture within the support frame, the at least one support surface providing a reference plane; the frame being supported on the microscope body with the viewing aperture in use aligned with the optical element and the at least one support surface at a distance from the optical element; a biasing mechanism including a first biasing element facing the at least one support surface and configured to apply a bias towards the at least one support surface; and a slide holder disposable between the support frame and the biasing mechanism; the biasing mechanism being configured to bias a slide in the slide holder to cause a top surface of the slide to abut against the at least one support surface of the support frame and thereby at the reference plane, so as to be spaced from the optical element by said distance.

The apparatus provides for accurate positioning of a microscope slide relative to the microscope optics, in practice irrespective of the thickness of the slide. Being made of glass, slides tend to be of very accurate planarity but can be of varying thicknesses. As a consequence, it can be difficult to provide precise sample analysis from slide to slide in a sequential, preferably automated, system. The apparatus overcomes this difficulty by precise positioning of the top surface of the slide, which typically carries the sample to be analysed, relative to the microscope optics, irrespective of thickness variations of the slides, which are accommodated by the biasing mechanism.

In the preferred embodiment, the biasing mechanism includes a second biasing element configured to bias a slide in a lateral direction relative to the at least one support surface, the apparatus including a lateral stop element against which a slide can abut, against the force of the second biasing element.

The second biasing element is able to position a slide in an accurate lateral position, which together with the vertical positioning, provides very precise positioning of a slide relative to the microscope optics.

In practical embodiments, of which a number are disclosed below, a positioning accuracy of a slide relative to the microscope optics of better than ±10 micrometres has been achieved.

Advantageously, the apparatus includes a first movement mechanism configured to move the frame relative to the microscope optics in a direction aligned with the optical axis of the microscope, that is towards and away from the optical element. The first movement mechanism enables the analysis of samples through the depth of the sample, in what could be described as a Z plane. Hereinafter the first movement mechanism is described as a vertical or Z plane movement mechanism.

Preferably, the apparatus includes a second movement mechanism configured to move the frame relative to the microscope optics in one or more directions relative to the optical axis of the microscope, that is sideways relative to the optical element. The second movement mechanism enables the analysis of samples across the lateral extent of the sample, in what could be described as a XY plane or a horizontal plane.

It will be appreciated that the apparatus may comprise either one of a vertical or horizontal movement mechanism and in the preferred embodiments both vertical and horizontal movement mechanisms.

In the preferred embodiments, the biasing mechanism is a spring mechanism. It may be formed of a single spring element or a multitude of spring elements, in the preferred embodiment of two spring elements, the first configured to provide the vertical bias and the second to provide the lateral bias.

The biasing mechanism preferably applies bias at two ends of a slide.

In the preferred embodiment, the slide holder, or cartridge, includes a plurality of laterally disposed slide receptacles, each slide receptacle holding a single slide. Advantageously, the slide receptacles are disposed in a common plane.

The slide holder may be of circular form, with slide receptacles arranged in a circular disposition in the holder. This embodiment allows for slides to be moved sequentially into the field of vision of the optical element of the microscope by rotation of the slide holder.

In another embodiment, the slide holder may be of linear form, with linearly arranged slide receptacles. In this embodiment, successive slides can be moved into the field of view of the microscope optical element by linear movement of the slide holder.

For these embodiments, the biasing mechanism is able to move across a slide in a slide holder, to engage with the subsequent slide in the holder. The apparatus may include a motor for moving the slide holder. Advantageously, the motor is a stepper motor; which is able to move in predetermined increments. In one embodiment a digital encoder is used to know the position of the plateau before any rotation or translation is applied, and to control the stop position of the loader.

The preferred embodiments include a position registration feature in the slide holder, for example an indent; and a position sensor configured to locate the position registration feature, as a further or alternative position sensor.

According to another aspect of the present invention, there is provided a slide holder or cartridge, which includes a plurality of laterally disposed slide receptacles, each slide receptacle holding a single slide.

The slide holder is preferably of planar form.

Advantageously, the slide receptacles are disposed in a common plane.

The slide holder may be of circular form, with slide receptacles arranged in a circular disposition in the holder. This embodiment allows for slides to be moved sequentially into the field of vision of an optical element of a microscope by rotation of the slide holder.

In another embodiment, the slide holder is linear form, with linearly arranged slide receptacles. In this embodiment, successive slides can be moved into the field of view of a microscope optical element by linear movement of the slide holder.

In both embodiments, the slide holder can be fitted to microscope apparatus with the slides held in the receptacles, that is without the need to remove the slides from the holder. Having a single layer of slides means that loading of slides into the holder is much simpler than in a system that stacks slides vertically, and also facilitates the analysis of slides. Once loaded into the holder, or cartridge, the slides do not need to be manipulated individually, and can be handled together via the holder itself. Moreover, the arrangement provides for more straightforward and reliable processing of slides, whether by a machine or a human.

Other aspects, features and advantages of the present invention will become apparent from the specific description that follows. Brief Description of the Drawings

Embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view in side elevation of an embodiment of microscope assembly according to the teachings herein;

Figure 2 is a plan view of a part of the embodiment of microscope assembly of Figure 1 , showing an embodiment of circular slide holder;

Figure 3 is a side elevational view of the part of the assembly shown in Figure 2;

Figure 4 is a front elevational view of the part of the assembly shown in Figures 2 and 3;

Figure 5 is a plan view of the part of the assembly shown in Figure 2 in a different point of operation;

Figure 6 is an enlarged view of element B of Figure 5;

Figure 7 is a cross-sectional view of a part of the microscope optical unit and components of Figures 2 to 6;

Figure 8 is a perspective view of the part of the assembly shown in Figure 2, in an open configuration;

Figure 9 shows the perspective view of Figure 8 with a circular slide holder in position;

Figures 10 and 11 are side elevational views of the microscope apparatus with the slide holder in different operating vertical (along direction Z) positions;

Figures 12 and 13 are plan views of the microscope apparatus with the slide holder in different lateral (along direction X) operating positions;

Figure 14 is a rear view of the part of the assembly shown in Figure 2;

Figures 15 and 16 are side elevational views of the part of the apparatus shown in Figures 2 to 14 in different lateral (along direction Y) operating positions;

Figure 17 is a plan view of the circular slide holder in position,

Figure 18 is a side elevational view similar equivalent to Figure 17; Figure 19 is a plan view of the slide holder itself, with a few slides mounted in receptacles in the holder;

Figures 20 and 21 show the operation of the biasing mechanism on a slide in the holder;

Figures 22 to 25 show different views of an embodiment of biasing mechanism, formed with two springs;

Figures 26 and 27 show different views of an embodiment of biasing mechanism, formed with one spring;

Figures 28 to 30 show different views of a the preferred embodiment of slide support assembly according to the present invention;

Figure 31 is a plan view of an embodiment of linear slide holder according to the present invention;

Figures 32 to 35 show different views of another embodiment of linear slide holder according to the present invention; and

Figures 36 and 37 are cross-sectional views across lines A-A and B-B of Figure 35, respectively.

Description of the Preferred Embodiments

There are disclosed various embodiments of apparatus and method to dispense microscope slides sequentially under a fixed microscope objective. One version comprises a circular loading tray (magazine or cartridge), in which openings are provided to accommodate microscope slides. Movement of the loading tray is motorized by means of a stepper motor and a friction wheel. A set of springs act as a biasing mechanism to push the slides against a support having a fixed plane, so that the ideal focus position is known and does not vary between slides. The mechanism can be mounted on any XY stage. When the XY stage is motorized, one obtains a XY-Theta movement, that is a set of slides can be scanned in the plane (XY) in sequence by applying a rotation between slides. When the Z movement is motorized, one can additionally scan through the depth of samples, which is highly desirable for biology and industrial hygiene sample analysis. The system therefore preferably provides a motorized XYZ-Theta movement. In one embodiment, a loading tray is loaded, at or away from the microscope, with up to twelve slides that are to be analysed. The loading tray is placed on the stage, a top support is closed, and twelve slides or fewer are sequentially captured and analysed by a control unit, for instance a tablet computer. The movement of the four motors is preferably controlled in a closed loop or an open loop by the control unit. The control unit camera captures the images and image analysis software performs qualitative and/or quantitative evaluation of the images to determine the nature of the samples on the slides.

The results are archived by slides and by steps in control software.

While a tray capacity of 12 slides is considered optimal in the described embodiments, the loading tray may conveniently hold from 3 to 20 slides.

A good microscope depends mainly on its optics and the accuracy of its stage. For this reason, there is no use for a slide loading mechanism on manually operated microscopes, as the aim is to concentrate on precise movement of the stage, which is achieved by having as few moving parts as possible. The situation is different when one wants to motorize the stage.

One solution is to motorize the microscope stage along three orthogonal axes (X, Y and Z). With careful slide preparation, this can enable one to scan samples automatically along pre-determ ined paths. Work by the applicant on asbestos fibre detection has shown that it is possible to diagnose fibres in 1/4 piece air filters in about 90 seconds. This performance is achievable by fully automating the diagnostic system, particularly by driving the motors in the three directions independently of one another, in a closed-loop with the capture and analysis performed by driving software. An example of software suitable for this purpose is disclosed in the Applicant’s earlier French patent number FR-3,067,112, which relates to the automated analysis of asbestos samples.

The embodiments disclosed herein enable a user to load multiple slides at once onto a holder or carrier. This can integrate well with laboratory practices, where an analyst usually prepares multiple slides at once, sequentially, and stashes them on a tray for later measurement. An aim is that, instead of loading the slides one by one on the microscope, a tray can be loaded with all the slides for measurement. Referring now to Figure 1 , this shows a perspective view of a microscope assembly 10 incorporating an embodiment of the present invention. The assembly 10 includes a microscope body 12 which in use is fixed in position. The body 12 supports a microscope head 14 as well as a cradle 16 for supporting a control unit, which may be a tablet computer or the like. The cradle 16 is held in position by a support element 18 and also, in this example, through the eyepiece cylinder 20 and the eye tube 22, which are in turn supported by the microscope head 14. The cradle 16 is preferably at a height and orientation suitable for the user.

The microscope head 14 includes a turret cover 24, which comprises a turret objective holder 26 that supports a microscope objective 30, in this embodiment a x40 objective although this could be of any other required magnification. A microscope condenser 32 is provided on a condenser support assembly 34, aligned with the objective 30 and disposed above a light source diaphragm 40. The microscope objective is typically screwed onto the turret objective holder 26 and can rotate along an axis at 20° to the Y axis.

A slide holder, or cartridge or magazine assembly, 50, described in further detail below, is supported on a Z-rail block 54. The z-rail block 54 enables the distance between a slide 60 in the cartridge 50 and the objective 30 to be moved in a Z direction, typically vertically, in order to focus the microscope relative to a sample located on the slide. On the whole, these components of the microscope assembly 10 are known in the art.

A first aspect of the disclosure herein provides a new design and structure for the cartridge, or holder, 50 which provides the following advantages:

• easy and precise loading of the slides

• use of a full or partially loaded tray

• easy mounting of the tray

• precise alignment of slides in three dimensions

• extremely fast alignment as the slides are self-aligned and do not require a closed-loop analysis to be set in place

• retaining the accuracy of the XYZ movement of the stage

• aligning the slide by rotation within better than 0.1 ° angle. The microscope system 10 of the embodiment of Figures 1 to 30, provides motorized movement of the microscope slides in the XYZ-Theta directions, in which X, Y and Z move the slide in three orthogonal directions, while Theta is the angle that the motor moves to locate the microscope slide in position under the microscope objective. In the embodiment of Figures 31 to 37 Theta is the linear distance the motor moves to locate the microscope slide in position under the microscope objective 30.

The cartridge 50 is in use fixed on the XY stage of the microscope, for instance by a knurled screw or the like and thereafter each slide is positioned accurately relative to the objective 30 by balancing it against a support in a fixed reference plane, which ensures extremely accurate location of the slide and in practice accurate focus, with less than ±10 micrometres of variation in the vertical position between slides. The mechanism also positions each slide in the XY position very accurately, within a similar tolerance of +10 micrometres. This is described in detail below.

Referring now to Figure 2, this shows a plan view of a first embodiment of apparatus having a circular slide holder or cartridge 50 into which a plurality of slides 60 can be disposed in a circular formation in slide receptacles 80, as will be apparent from the view of Figure 2. In this particular example, the cartridge 50 is configured to be able to support a maximum of twelve slides 60 in individual receptacles 80, although the cartridge 50 could of course be designed to hold a greater or lesser number of slides 60. Each receptacle 80 is in the form of an opening or slot in the cartridge 50 and has first and second end flanges 82, 84 spaced from a top surface of the cartridge 50 by a distance preferably equivalent to the thickness of a slide, although this may be less or more than a slide thickness. Each receptacle 80 includes opposing central side openings or recesses 86, 88 to accommodate a user’s fingers, tongs or other tool, enabling easy loading and removal of slides into and from the cartridge. The central position of these holes or recesses allows a slide to be held centrally for balance. Each receptacle 80 also includes slots 90, 92 disposed at one side of the opening of the receptacle and extending orthogonally to the longitudinal dimension of the receptacle 80, for purposes disclosed in detail below.

The cartridge 50 can be fixed to a motorized unit, described in further detail below, by means of a nut or other fastener 94.

The assembly includes a support frame 100, which provides a reference plane at a lower support surface, detailed below, which in this embodiment is rotatable around a pivot pin 102 in a clockwise direction in the view of Figure 2 and closed against a stop 104. The support frame 100 has a viewing aperture or window 106 through which a slide positioned for viewing can be located within the field of vision of the microscope optics 30. Located adjacent the support frame 100 is an axis holder 110, described in further detail below, and a position sensor 120 with a cam element 172 that locates within an indent or recess 170 in the cartridge 50 for positioning purposes, also described in further detail below.

An electric motor 122 is supported by a motor support 124 and in use provides X-axis movement of the assembly including the cartridge support in the X-axis direction.

Referring now to Figures 3 and 4, these show different views in lateral elevation of the components of Figure 2. The support frame 100 provides a first reference plane, used to position a side 60 in precise positon relative to the microscope objective 30. It is in this embodiment and with reference to Figure 2, the reference frame 100 is rectangular with a precisely flat bottom or reference plane surface, being both planar and also disposed orthogonally relative to the focus or imaging plane of the microscope objective 30.

The pivot point 102 is, in this embodiment, coaxial with a second reference plane 132, opposite which there is a third reference plane 134. The motor 122 drives a rubber wheel 140 (not visible in Figures 3 and 4) via a rubber wheel coupler 142.

The apparatus includes also a Y-stage ground 150 and a Z-stage body 152.

The pivot 102 includes a spaced shoulder screw 103, around which the reference frame 100 can pivot. The pivot also provides a temporary stage body 130, described in further detail below, in particular in relation to Figures 7 and 8. As will be apparent in particular from Figures 3 and 4, the slide holder and cartridge 50 is disposed in what could be described a slot between the reference frame 100 and the temporary stage holder 130, able to rotate within the slot around its axis of rotation, at the location of the fixing nut 94. Rotation is achieved by the motor 122, supported on the assembly by motor support 124 and preferably by means of a friction wheel.

With reference now in particular to Figure 5, the slide holder or cartridge 50, in this embodiment, rotates anti-clockwise in the direction of arrow 160 to move successive slides 60 held in the receptacles 80 so as to align these, successively, with the microscope objective 30, this being achieved by the motor 122. The reference frame 100 is preferably arranged, in what could be described as a home position, such that a slide 60 to be analysed is located at the centre of the frame 100. The viewing window of the frame 100 is sufficiently large that is allows the slide holder 50, and as a consequence the slide 60, to be moved in the X and Y planes while still allowing the objective 30 to focus upon different parts of the slide. The frame 100 will not impinge upon the line of sight of the objective 30 as the slide 60 is moved relative to the objective 30.

As can be seen in particular in Figure 5, the receptacles 80 are preferably provided with enlarged, rounded, corners 81 , which assist in the easy placement of slides 60 into the receptacles 81 while ensuring perfect contact between two sides of the slide and the receptacle and avoid possible damage to the edges of the slides.

The holder or cartridge 50 is also provided with recesses or indents 170, which are spaced evenly with relation to their associated receptacle 80, used in positioning a receptacle 80 and associated slide 60 in the line of sight of the microscope objective 30.

With reference to Figure 6, which is an enlarged view of section B of Figure 5, this shows the position sensor 120, which includes a cam follower or button 172 at the end of a switch actuator, which in practice will move into the indent 170 on rotation of the cartridge 50, thereby detecting the indent 170 and, as a consequence, the relative position of the associated, in this example, trailing, receptacle 80 and slide 60. The position sensor, being coupled to the motor 122, acts to stop the motor 122 upon triggering of the cam switch 172. The motor 122 is preferably a stepper motor which, in combination with the position sensor 120, is able to rotate the cartridge 50 and stop it with the receptacles 80 and slide 60 in the correct position reliably and repeatedly, from slide to the slide within the cartridge.

With reference to Figure 7, this is a cross-sectional view of this part of the microscope assembly 10, across the microscope objective 30 and the condenser 32. Below the cartridge 50 is the temporary stage body 130, upon which the cartridge 50 can rest and be supported. A slide 60 is disposed between the microscope objective 30 and the condenser 31 and in practice held against the bottom surface of the reference frame 100 and as will be apparent from Figure 7, by means of a mechanism described in further detail below. A needle cage 180, also described in further detail below, provides additional support for the cartridge 50, particularly as it rotates into the temporary stage body 130.

With reference now to Figure 8, this shows a perspective view of the assembly of Figure 7 in particular, without the cartridge 50 in place. The frame 10 has been pivoted around the pivot point 102 into an open position, typically adopted for loading and removing a cartridge 50 from the apparatus. This Figure shows in better detail the arrangement of the motor 122 on the motor support 124, including the rubber wheel coupler 142 and rubber wheel 140 attached to the coupler 142 and the motor shaft of the motor 122. The rubber wheel 140 is configured to engage the outer periphery 51 (see Figure 9) of the cartridge 50 in order to rotate the cartridge around the axis 95 upon which the holder screw is fixed in use. The cartridge 50 is typically held by the needle cage 180, which itself is in the form of a disk able to rotate around the axis 95 and which includes a plurality of radially arranged ribs which engage with corresponding recesses (not shown) in the underside of the cartridge 50, to ensure that there is no slippage between the cartridge 50 and the support 180 during use.

The temporary stage body 130 includes, preferably, a planar support frame having a central aperture therein to accommodate the microscope condenser 32, below which the condenser support assembly 34 is located, in conventional manner. The position sensor 120 is disposed on the temporary stage body 130 and at a location consistent with the positioning of an associated receptacle 80 and associated slide 60 at a centre point below the objective 30 the microscope and typically in the centre of the frame 100 when closed over the cartridge 50.

Referring now to Figure 9, the part of the apparatus of Figure 8 is shown with a cartridge 50 fitted thereon and with the central axis 93 of the cartridge in practice aligned with the axis or spindle 95.

It can be seen in particular in Figure 9 that the cartridge or holder 50 is designed to hold a single slide 60 in each receptacle 80, such that all of the slides in the receptacle 50 are disposed in a side-by-side, or horizontal, arrangement, rather than in a vertical stack as is the case with prior art systems. The receptacles 80 are not designed to hold more than a single slide. In practice, therefore, a user will load one more slides 60 into a cartridge 50 in a side-by-side relation, which makes the loading of the slides easier, something that can be done manually or automatically. It also permits the positioning of the slides 60 to a microscope objective 30 by simple movement of the cartridge 50 without it being necessary to manipulate the slides 60 separately from the cartridge. Moreover, all of the slides can always be held and supported within the cartridge 50, without it being required to manipulate slides from the cartridge 50 for analysis purposes. This contrasts with prior art systems which stack slides in a vertical arrangement in a cartridge or other holder, and form which individual slides must be removed from the cartridge or holder for positioning under the microscope objective.

With reference to Figures 10 and 11 , these are perspective views of the assembly of Figure 1, which the cartridge 15 in position and showing how the whole assembly of the cartridge holder can be moved by the Z-rail block 54 in a Z-direction, or vertical direction, in order to move a slide 60 closer to and further from the microscope objective 30, in use enabling focusing to different levels through the depth of a sample on the slide 60 without having to move the microscope objective 30 or, in practice, without having to move a slide 60 relative to the microscope assembly 10, as is necessary in prior art systems. For this purpose, the apparatus 10 includes within the server-rail block 54 a motor configured to move the server-rail block upwards and downwards as per the views of Figures 10 and 11. Referring now to Figures 12 and 13, these show a plan view of the components of Figures 8 and 9, with the cartridge 50 in position on the assembly. The cartridge 50 is mounted on X stage body 152, as is the motor 122. These are movable in an X-direction by an X-stage motor (not visible in the drawings) so as to move the cartridge assembly and support components in an X-direction relative to the reference frame 100 and in practice relative to the microscope objective 30. This enables the microscope system 10 to analyse a sample across a width of a slide 60.

With reference to Figure 14, attached to the microscope frame 12 is an X- stop plate 190 which includes two stop shoulders 192, 194, within which the motor holder 124 is located. In practice, the motor holder 124, and as a consequence the cartridge 50, can only be moved between the stops 192, 194 in the X-plane, thereby ensuring X-plane movement within predetermined limits. It will be appreciated, in particular with regard to Figures 12 and 13, that the frame 100 is preferably shaped and sized so as to provide a viewing window to the appropriate slide 60 across the whole range of X-plane movement defined by stop shoulders 192, 194.

With reference now to Figures 15 and 16, the apparatus includes a third motor, in practice a Y-plane motor, within the Y-stage 150, that enables movement of the cartridge or holder 50, as well as the motor and motor support 122, 124, in a Y-plane, so as to adjust the position of the slide 60 relative to the microscope objective 30 in a Y-direction, that is in in the longitudinal direction of the slide. It will be appreciated, therefore, that the system preferably provides for adjustments in the X, Y and Z planes, while keeping the slides 60 in stable relative positions and without it being necessary to manipulate the slides 60 separately of the apparatus or cartridge 50. Moving the entire assembly of cartridge slide holder 50, support and motor assembly 122, 124 provides a simple apparatus and more reliable and precise movement of a slide relative to the microscope objective 30. It will be appreciated that in these embodiments the reference plane provided by the frame 100 is precisely positioned relative to the microscope body 12 and since the slides 80 are precisely positioned against the reference plane of the frame 100 their position is also precisely known. As a consequence, the frame 100 provides a constant and reliable reference plane relative to the microscope objective 30, able to be moved by virtue of the X, Y and Z position changes controlled by the operator and/or the microscope assembly in order to analyse different parts of a sample on a slide, all without risking any inaccuracy caused by separate manipulation of a slide relative to the system. In practice, it is preferred that the reference frame 100 is fixed in the Z direction when moved in the XY direction, in order to maintain a precise Z alignment with the microscope objective 30 during such movement.

With reference now to Figure 18, this shows a cross-sectional view in side elevation of, in particular, the motor 122 and a cartridge 50. As can be seen, attached to the spindle of the motor 122 is the rubber wheel coupler 124, to which there is fitted a rubber wheel 140, which contacts with a friction fit the peripheral edge 51 of the cartridge 50, such that rotation of the rubber wheel 140 causes rotation of the cartridge 50 around the axis 95, to which the cartridge 50 is fitted and held by the holding nut 94. The needle cage 180 ensures smooth rotation of the cartridge 50 and the axis holder 110 ensures that there is no deflection of the cartridge 50 caused by friction against the rubber wheel 140. Then inventors have found that this arrangement provides a reliable and effective mechanism for moving the cartridge 50 and as a result slides 60 held in the cartridge across the main viewing plane of the microscope assembly.

With reference to Figure 19, this shows a plan view of the preferred embodiment of cartridge 50, which is shown holding five slides 60. The cartridge preferably includes numbered receptacles from 1 to 12, in this example, with a loading position identified by arrow 57 on the surface of the cartridge. The loading position indicator 57 is intended to be used by a user to align the cartridge 50 with respect to the microscope assembly 10, such that the system can, under control of the control unit, sequence through the slides 80 held in the cartridge 50 and to stop once the cartridge 50 has been through one complete revolution. In such an event, the cartridge 50 can be realigned with the arrow 57 prior to being removed from the assembly, which would involve rotating the reference plane 100 out of the way, as shown in Figures 8 and 9, by unscrewing the holding nut 94 and then removing the cartridge 50 as a whole with the slides 60 therein, potentially for replacement with another cartridge having another batch of slides therein. The arrow 57 is positioned, in this embodiment, between two receptacles 80 and such that when aligned there is no slide 60 immediately below the microscope objective 30 and also no slide within the mechanism, described below, for aligning the slides against the lower, reference, surface of the reference frame 100. So doing ensures that the slides 60 are properly held within their receptacles 80 during loading and unloading of the cartridge 50 onto the microscope system.

The system preferably provides the ability to use cartridges that are not completely filled with slides, that is which may have empty receptacles as shown in the example of Figure 19. In such an event, the control unit (for example tablet computer) used to control the microscope assembly 10 can detect the absence of a slide in a receptacle 80 and then cause the system to rotate the cartridge 50 to the next receptacle in sequence, to determine therefrom whether there is a slide in that subsequent receptacle, if so to carry out the required analysis and if not to continue to the next receptacle 80 in sequence. As a consequence, it is not necessary for the cartridge 50 to be completely loaded with slides. It can be part-loaded in cases where only a smaller number of slides are required to be analysed that the capacity of the cartridge 50.

It will be appreciated also that the system can operate with cartridges of different capacities, for example cartridges of the same dimensions but that hold a fewer or more slides, always in a single plane, with one slide per receptacle. The recesses or indents 170 of the cartridges provide a mechanism to stop rotation of the cartridge 50 at the appropriate location of a receptacle 80 and associated slide 60. For instance, a cartridge 50 having a fewer number of receptacles 60 will have a consistently fewer number of indents or recesses 170 and the motor 122 will simply rotate the cartridge through greater radial intervals until a receptacle and slide is in position below the objective 30.

Referring now to Figure 20, this shows a side-elevational view of the cartridge 50 and reference frame 100, overlying the temporary stage body 130 and the A axis holder 110 on the Y-stage ground. Figure 20 includes an enlarged sectional view of the portion marked A in the upper drawing of Figure 20, which shows a first sprung element 200 which has a upwardly curved portions 202 at a centre point of the spring. The spring 200 is fixed to the temporary stage body 130, in this example by first and second depending feet 204 (visible in Figures 22 and 23), with the other end 206 free to slide on the temporary stage body 130. As will be apparent in Figures 22 and 23, the spring 200 includes two arms separated by the section 206. The two upwardly curved central portions 202 are spaced from one another by a distance equivalent to the space between the slots 90, 92 of the recesses 60 of the cartridge or holder 50. The upwardly curved portions 202 extend through the slots 90, 92 to abut the lower surface of a slide 60 and in practice adjacent each end of the slide 60.

As will be apparent from the large section A of Figure 20, the upwardly curved portions 202 of the spring 200 provide an upward biasing force against a slide 60, in practice pushing the top surface of the slide 60 against the lower, reference plane, of the reference frame 100. As a consequence, the top surface of every slide 60 is positioned at the same vertical position relative to the reference plane 100 irrespective of the thickness of the slide 60. As slides 60 are typically made of glass, they have a very smooth and planar upper surface but their thickness can vary from slide to slide, for example from manufactured batch to batch, the source of the slide ,and so on. This mechanism accommodates for those changes in the thickness and provides a very reliable Z position of the slide and as a result focus point into a sample held on the slide. In practice, the inventors have been able to positon the slides with an accuracy of +10 micrometres.

With reference now to Figure 21 , in conjunction with Figures 22 to 25, the preferred embodiment includes a second spring 210, which in practice is disposed within the perimeter of the first spring 200 and which includes first and second slanted surfaces 212 facing towards the capture points 214 (similar to the points 204) at a side of the spring 210 which is fixed to the temporary stage 130. As will be apparent, in particular from Figure 23, the spring 210 includes two angled surfaces 212, each disposed alongside a respective curved element 202 of the first spring 200 and in practice also aligned with the slots 90, 92 in the recesses 60 of the cartridge 50 to be able to pass through these slots. These surfaces 212 can, as a result, extend above the inner surface of a slide 60, in order to apply, in this example, a lateral force as indicated by the arrows in the enlarged section B of Figure 21. This pushes a slide 60, in practice against the side 61 of the recess 80. As the recess 80 is at a known position (determined by the position sensor 120 and separate motor 122, a slide 60 can be accurately positioned relative to the microscope objective 30 irrespective of the lateral dimensions of the slide 60.

Thus, a slide 60 can be accurately positioned, not only in terms of its distance relative to the microscope objective 30 (by means of the reference plane 100) but also laterally, by means of the springs 200, 202. Whilst not included in this embodiment, it is not excluded that a further spring may be provided to align a slide in the Y direction, such a spring being similar to the spring 210.

The inventors have found in practice that two springs 200, 210 are optimal, in particular as these work independently of one another yet in a co-ordinated manner. However, it is envisaged that a single, combined, spring could be used, of which an example is shown in Figures 26 and 27. The spring 200’ includes upwardly curved elements 202’ and angled surfaces 212’ separated by a spacer section 206’, with the relative elements 202’ and 212’ providing the same functionality as those of the two springs 200 and 210 of Figures 20 to 25. As explained, however, it is preferred that two springs are used instead of a single one.

Figures 28, 29 and 30 show, respectively, side elevational, plan and perspective views of the components shown in particular in Figures 8 and 9, without cartridge 50 and without the microscope condenser and condenser support assembly.

Referring now to Figure 31 , this shows another example of slide holder or cartridge 250, which is similar in many respects to the cartridge 50 of the previous embodiment. The cartridge 250 is what could be described as a linear cartridge having a plurality of slide receptacles 260 arranged in linear fashion, such that slides are disposed alongside one another in a straight line in the cartridge 250. The receptacles 260 have, in this example, recesses 262 for loading and unloading slides into the recesses, which are located at one end of the recesses 260. This is one particular arrangement and in other embodiments the recess 260 could have side openings similar to those shown with the circular cartridge. Similarly, the recesses 260 are preferably provided with transverse slots similar to the slots 90, 92 of the cartridge 50 of the previously described embodiment.

These slots accommodate springs 200, 210 or 200’ of the type shown in Figures 22 to 27. It will be appreciated that with such a cartridge 250 in place of a rotation mechanism there will be provided a motor and guides that feed the cartridge 50 in a linear direction across the microscope objective 30 rather than in a rotary manner. The skilled person will readily be able to envisage such a motor.

The cartridge 250 is preferably provided with recesses or indents 270 similar to the recesses or indents 70 of the first-described embodiment for positioning purposes.

Referring now to Figures 32 to 35, these show practical embodiments of linear cartridge 250’, which in this embodiment is provided with a tapered holding tab 254 for ease of manipulation by a user or automated handling system. In the schematic diagrams of Figures 32 to 35, the cartridge 250 can move in a linear manner across microscope objective 30, still retaining the advantages the accurate reference plane 100 for precise positioning relative to the microscope objective 30.

It is believed that this offers a convenient alternative form of cartridge and one that can provide a greater density of slides relative to surface area of cartridge. Moreover, these embodiments provide for linear movement of the cartridge 250 rather than rotational movement, which can simplify the apparatus and its use. While not shown in the drawings, this embodiment of apparatus will include a holding mechanism similar to the needle cage 180 of the rotational embodiment, typically a support structure that holds the cartridge 250 in position so that it can be moved by the stepper motor 122 reliably. It will be appreciated that the indents 170 in the cartridge, as with the rotational embodiments, will ensure accurate positioning of the slides 60 relative to the microscope objective 30 in any event.

Figures 36 and 37 are cross-sectional views taken along the lines A-A and B-B respectively of Figure 35. Flaving regard to the disclosures above, the characteristics and elements shown in these drawings will be immediately evident to the person skilled in the art so are not described again herein. In all embodiments, it is preferred that the holder or cartridge has a flatness better than 0.4mm over a diameter or length of 300mm.

As the cartridge is removable, the slides 60 can be prepared at another work post can then loaded in a sequence on the cartridge 50. The cartridge 50 can be loaded and used, that is taken to a microscope assembly 10, at a later time. Thus, several cartridges 50 can be loaded, and even stacked on top of one another, in wait for the end of the diagnostics of another cartridge 50 of slides. For this purpose, the slide recesses provided in the receptacles 80 of the cartridge 50, 250, that is to the flanges 90, 91 , can be of sufficient depth to accommodate the height of a slide and a sample on the slide. Additionally or in the alternative, the cartridge 50, 250 could be provided on its top and/or bottom surfaces with one or more spacer protrusions, such as bosses or ribs to space the slides of one cartridge form the bottom surface of an overlying cartridge.

The arrangement of indent or recess 170 has been found to enable radial alignment better than 0.1° in all cases.

As such, the cartridge 50 plus its support and motors can provide a high precision conveying mechanism.

The XY motors provide direct transfer movement with the cartridge 50, allowing a displacement of 125pm per step in the X direction, and 240pm per step in the Y direction. Lower steps can be reached by using motor drivers that enable fractional steps to be applied. In practice, full steps are used at x40 magnification.

The Z movement is completely independent of XY-Theta, and can achieve 0.5pm per step without requiring fractional steps.

The cartridge may hold 3 to 20 slides. In practice, we the inventors have found that 12 receptacles are ideal in terms of dynamics, vibration, and precision. The magazine allows for a sequence of slides to be measured. When the diagnostic routine of one slide has been completed, the cartridge 50 rotates or slides until it reaches a resting position, and a diagnostic sequence of the next slide is further launched.

Loading of the cartridge with slides is performed on or away from the microscope. This enables the preparation of several cartridges in advance. In a typical setting, an operator will prepare the slides in advance, load them in the cartridge, and eventually refer the cartridge and its contents in a laboratory information management system (LIMS). The cartridges can be stashed and loading them on the microscope can be performed sequentially.

Loading the cartridge on the microscope proceeds as follows:

• The user opens the reference frame 100

• The user insert the cartridge 50 filled with slides 60 (arrow along the Y axis)

• The user tightens the screw 94

• The user closes the reference frame 100

• The user launches the testing of the 12 slides with a tablet computer mounted on the cradle 16

• The rubber wheel 140 rotates thanks to the motor 122

• The rubber wheel 140 rotates (or slides) the cartridge 50 by friction

• When the end stop 172 drops inside one of the indents 170 of the cartridge 50, it stops the motor 122rotation.

• The first slide 60 is ready to be analysed.

The analysis is as follows, for each step:

• Focus (movement along the Z axis)

• capture of an adequate number of images

• image treatment followed by an analysis

• determination of a focus correction

• optionally, storing of the image or images from the step

• Field change (movement along the X or Y axis or both)

• application of the focus correction

• repeat first step.

The analysis completes when the all the steps have been performed following a pre-determined path.

When one slide has been captured, the next slide is presented under the objective:

• The rubber wheel 140_turns thanks to the motor 122

• The rubber wheel rotates (or slides) the cartridge by friction • When the end stop 170 drops into the next slot of the magazine, it causes the stop of the motor 122_rotation.

- The next slide 60 is ready to be analysed The process is repeated for the 12 slides. It will be appreciated that the teachings herein are not dependent upon a particular shape or dimension of slide 60. Should slides of other geometry be used, for instance square 75x75mm, the receptacles 80 can be adapted through proper dimensioning. This is also true for circular samples, such as those used in materials science. It is to be appreciated that while the described embodiments provide indents 170 on the holder or cartridge 50, 250, any other position indicator can be used, such as an optical or magnetic indicator. An optical indicator may include, for example, a coloured markings on the slide holder or apertures in the slide holder for the passage of a light beam therethrough, and an optical sensor. A magnetic indicator may include for instance magnets on the holder and a magnetic sensor to detect the presence of one of the magnets.

The disclosure in the abstract accompanying this application is incorporated herein by reference.