Patent Description:
Especially in the field of microscopic examination of living samples like cells, it is of great interest to keep the sample as long as possible under favourable and stress-free environmental conditions. To this end, incubators are used for generating a microclimate adapted to the sample to be examined. Existing incubators can be distinguished in stage top incubators, on the one hand, and cage incubators, on the other hand.

Cage incubators comprise a climatic chamber enclosing the entire microscope or at least the main components of the microscope, such that a large volume needs to be incubated. Access to the working area for placing or manipulating the sample is impaired since the microscope itself is located within the cage incubator. Further, it is hardly possible to equip a microscope with a cage incubator in a space-saving manner. On the other hand, a stage top incubator provides a small volume to be incubated as the stage top incubator only encloses the sample itself and is placed onto the microscope stage. Even if a stage top incubator has minimum space requirements, access to the sample is impaired since the sample is surrounded by a sealed box which would have to be opened, thus, destroying the incubation atmosphere within the box.

<CIT> discloses a culture microscope having a housing section which serves as an incubator chamber for controlling an incubation atmosphere in which cells to be examined are cultured. The incubator chamber also includes the microscope stage and the objective lens. Separated from this incubator chamber and in another housing section, the illumination unit and the remaining components of the imaging optics are located. The incubator chamber comprises a lid which can be opened to provide access to the sample. While such a solution provides free access to the sample, the drawback of such incubation systems is that with every opening and closing of the lid, incubation atmosphere escapes the system very easily and needs to be replenished almost in full after every opening and closing of the lid.

<CIT> discloses a climate compartment surrounding main parts of a microscope and having a door. An air flow is provided by means of a fan. <CIT> discloses a microscope with a housing, wherein an air flow is provided. <CIT> discloses a laboratory incubator comprising a fan and a flow channel.

In view of the drawbacks described above, there is a need for an improved sample chamber solution in microscopes, particularly in microscopes comprising an incubated sample chamber.

Embodiments of the present inventive concept provide a microscope for microscopic examination of a sample according to claim <NUM>.

The present inventive concept thus provides a microscope including a relatively large sample chamber providing free access to the sample, and, at the same time, providing a flow of atmosphere through the sample chamber. In this context, it should be noted, that the present inventive concept is not limited to incubated sample chambers, but can also be used in microscopes where a flow of atmosphere, particularly a laminar flow may be beneficial to the examination of the sample or to the sample itself.

The present inventive concept provides the advantage of a directed flow of atmosphere through the sample chamber, the flow preferably being a laminar flow or an essentially laminar flow. Such a directed flow of atmosphere has a number of advantages. First, the flow can entrain any particles, like dust, dirt, and germs, entering the sample chamber and transport them to an exit opening. Second, the directed flow acts like a shield or curtain preventing atmosphere from escaping the sample chamber and preventing external atmosphere from entering the sample chamber. These effects allow for a (semi)sterile work environment around the sample placed on a microscope stage inside the sample chamber. Further, in case of an incubated sample chamber, it is possible to recycle incubation atmosphere. Incubation atmosphere drained out of the sample chamber may be recycled and blown back into the sample chamber. A part of the incubation atmosphere may be refreshed or replenished. This saves incubation atmosphere volume and energy after opening and closing of the door of the sample chamber.

In the first alternative of the present inventive concept, the first fan assembly comprises one or more fans for blowing atmosphere through at least one first opening in the first side wall of the sample chamber. The first fan assembly is preferably arranged close to or directly at the at least one first opening, and preferably outside the sample chamber, or in the at least one first opening. The at least one first opening may be a single opening covering the one or more fans/blowers of the first fan assembly or may consist of two or more openings for conducting atmosphere blown by the first fan assembly into the interior of the sample chamber, each opening being preferably assigned to one of the plurality of fans of the first fan assembly. Furthermore, in the first alternative of the present inventive concept, at least one second opening is arranged in a second side wall of the sample chamber, the second side wall being different to the first side wall, for allowing atmosphere from inside the sample chamber to exit the sample chamber. Similarly, more second openings can be provided in the second side wall of the sample chamber.

In a preferred embodiment, the location, geometry and size of the at least one second opening is determined such that a non-turbulent flow of atmosphere, preferably a laminar or essentially laminar flow is created. The creation of a laminar flow can also be influenced by location, number, and power of the fans of the first fan assembly as well as by the number, sizes, geometries and locations of the first opening(s). The first side of the sample chamber is opposite the second side of the sample chamber in order to create a steady flow of atmosphere through the sample chamber. Further, according to the invention, the first side is a top side, and the second side is a bottom side of the sample chamber, and the first side wall is a top side wall and the second side wall is a bottom side wall of the sample chamber. In most cases, the sample chamber is of rectangular solid form or of essentially rectangular solid form or of a cubic or essentially cubic form.

According to the second alternative of the present inventive concept, the first fan assembly is constructed as a suction fan assembly for draining atmosphere out of the sample chamber through the at least one first opening, such that the at least one second opening allows atmosphere from outside the sample chamber to enter into the sample chamber. The same considerations regarding the first fan assembly, the at least one first opening and the at least one second opening apply here in order to preferably create a non-turbulent flow of atmosphere, more preferably a laminar flow or an essentially laminar flow of atmosphere through the sample chamber.

In another preferred embodiment, a second fan assembly is arranged on the second side of the sample chamber for draining atmosphere through the at least one second opening out of the sample chamber, in the first alternative, or for blowing atmosphere through the at least one second opening into the sample chamber, in the second alternative. The second fan assembly can thus be regarded a support for creating an additional suction or blowing pressure for draining or blowing atmosphere through the second opening. The second fan assembly may comprise a single fan or a plurality of fans/blowers arranged close to or at the at least one second opening, and preferably outside the sample chamber, or even in the at least one second opening. Depending on the power of such a second fan assembly, it is possible to use only one single fan for creating sufficient suction power for draining atmosphere out of the sample chamber. In contrast, it is preferred to use one or more fans/blowers as the second fan assembly when used as a blower for blowing atmosphere into the sample chamber.

It is advantageous if the first fan assembly is configured to blow atmosphere through the at least one first opening and is arranged in or at the first side wall. Further, it is preferred if the first side wall is at least a part of the top side wall of the sample chamber. According to this embodiment, a flow of atmosphere is created from the top side of the sample chamber down to the bottom side, preferably a flow in the direction of the microscope stage and/or the sample.

It is also advantageous if the second fan assembly is configured to drain atmosphere through the at least one second opening and is arranged outside the second side wall. It is further advantageous to use only a small number if not only one fan for creating suction power outside the second side wall to drain atmosphere through the second opening(s).

In a preferred embodiment, the door of the sample chamber is arranged laterally of the first and the second side walls of the sample chamber such that a main direction of access into the sample chamber (corresponding to the surface normal on the door surface when the door is closed) is perpendicular or essentially perpendicular to the direction of the flow of atmosphere. In the normal case of a sample chamber being of essentially rectangular solid form, the sample chamber preferably includes at least one side door as the door providing access into the sample chamber. The at least one side door is a door in a third and/or fourth side wall of the sample chamber, the third/fourth side wall being (essentially) perpendicular to the first/second side wall. With such an arrangement, any contamination carried in by a user accessing the sample chamber through the opened door is entrained by the flow of atmosphere and transported to the exit openings. This set up allows for a (semi)sterile work environment for the sample. At the same time, the amount of atmosphere escaping or entering the sample chamber is drastically reduced since the flow of atmosphere acts as a curtain or shield preventing atmosphere from inside the sample chamber escaping or atmosphere from outside the sample chamber entering the sample chamber during opening the side door.

In a preferred embodiment, the second openings are arranged around and/or next to a microscope stage arranged at the bottom side inside the sample chamber. In this embodiment, the flow of atmosphere is directed from the at least one first opening to the second openings arranged around and/or next to the microscope stage where the sample is to be placed. Thus, at least a part of the microscope stage can be surrounded or protected by a flow of atmosphere. It is further preferred to arrange the second openings such that a shield or curtain is formed against an access direction from the door of the sample chamber.

In a preferred embodiment, the sample chamber is arranged inside a microscope housing of the microscope which microscope housing encloses at least partly the sample chamber. It is preferred if a separated housing section forms the sample chamber, especially if the sample chamber is used as an incubated sample chamber. The door providing access into the sample chamber preferably is a door in the microscope housing, i.e. the sample chamber and the microscope housing share this door.

Further, it is advantageous if the microscope housing provides space for recirculation of atmosphere outside the sample chamber for recirculation of atmosphere between the at least one first opening and the at least one second opening. In this embodiment, the sample chamber is surrounded by a microscope housing, e.g. in the form of a microscope housing section, and atmosphere drained out of the sample chamber is blown into the surrounding housing section. In this housing section, the atmosphere can be replenished and/or its temperature and composition can be adjusted, and then, the adjusted atmosphere can be reintroduced into the sample chamber.

In this context, it is preferred if the microscope housing surrounding the sample chamber also encloses the second fan assembly, particularly if this second fan assembly is configured to drain atmosphere through the at least one second opening out of the sample chamber.

It is advantageous if a first filter system is provided configured to filter atmosphere flowing through the at least one first opening. The filter system may be arranged at or in the at least one first opening. Such a first filter system is especially useful in the first alternative of the present inventive concept when atmosphere is blown through the at least one first opening into the inside of the sample chamber. The first filter system can help clean the atmosphere flowing into the sample chamber from any particles like dust, dirt or germs.

It should be noted that it may also be advantageous to provide another (second) filter system configured to filter atmosphere flowing through the at least one second opening. Such an additional second filter system is especially useful in the second alternative of the present inventive concept As to its advantages, reference is made to the description of the first filter system.

Furthermore, it is advantageous if at least one third filter system is provided and configured to filter air flowing through one or more openings or leaks of the microscope housing surrounding the sample chamber into the interior of said housing. The existence of such leaks in microscope housings is most commonly inevitable. Said openings can also be small openings for refreshing the atmosphere inside the microscope housing with fresh air from outside the microscope housing. Again, the third filter system helps clean any atmosphere entering the inside of the microscope housing.

In general, it might be reasonable to provide any openings and/or leaks of the sample chamber and/or of the surrounding microscope housing with filters or filter systems as described above.

As already mentioned above, it is particularly preferred if the first fan assembly, the at least one first opening and the at least one second opening of the microscope according to the present inventive concept are configured to generate a laminar flow through the inside of the sample chamber. As opposed to turbulent flows, a laminar flow can work best as a curtain or shield and can most efficiently entrain any particles and transport them to exit openings.

As also discussed above, the present inventive concept may be particularly used for incubated sample chambers containing an incubation atmosphere. Such microscopes can provide a user-defined incubation atmosphere with predetermined contents of H<NUM>O and CO<NUM>. Additionally, N<NUM> may be introduced for displacing O<NUM> in order to reduce the oxygen content. Typically, the temperature of such an incubation atmosphere is controlled.

Embodiments of a second aspect of the present inventive concept provide a method of operating a microscope for microscopic examination of a sample according to claim <NUM>.

It is pointed out that the features described above in relation to the microscope according to the first aspect of the present inventive concept represent an analogous description of the corresponding features of the method according to the second aspect of the present inventive concept.

In a preferred embodiment of the method of the present inventive concept, the flow or the laminar flow or the essentially laminar flow is generated, more specifically continued to be generated, while a door providing access into the sample chamber is open for accessing the sample chamber, for example, for inserting a sample into the sample chamber, for removing a sample from the sample chamber or for manipulating a sample in the sample chamber.

In another preferred embodiment, the flow or the laminar flow or the essentially laminar flow is generated during microscopic examination of a sample in the sample chamber. In this embodiment, starting the generation of the atmosphere flow can be triggered with starting the microscope itself or can be switched on by a user at an early point of microscopic examination of the sample. In order to achieve the above advantages of a (semi)sterile working environment and of saving incubation atmosphere, it is advantageous to start generating the flow of atmosphere at the time of turning on the microscope and to continue the generation of the flow of atmosphere during every opening and closing of the door/lid providing access into the sample chamber.

In the following, the figures are described comprehensively, same reference signs designating same or at least structurally identical components.

<FIG> schematically shows an embodiment of a microscope <NUM> of the present inventive concept, the microscope <NUM> comprising a microscope housing <NUM> surrounding, at least partly, a sample chamber <NUM>. The microscope <NUM> comprises an illumination optics <NUM> for illuminating a sample, and an imaging optics <NUM> for imaging the sample. The sample is designated <NUM> and is placed on a microscope stage <NUM>. Thus, in this embodiment, microscope <NUM> is an inverted transmitted-light microscope. The sample chamber <NUM> forms a separated space and is preferably formed by a housing section of the microscope <NUM>. The sample chamber <NUM> may be an incubated sample chamber comprising incubation atmosphere which is adapted e.g. for the examination of living cells. In this embodiment, the sample chamber <NUM> includes the illumination optics <NUM> and the upper part of the microscope stage <NUM> and of the sample carrier including the sample <NUM>. Imaging optics <NUM> are arranged below the microscope stage and comprise a microscope objective and further optical components and optionally a camera or the like for generating/viewing a microscopic image of the sample <NUM>. Such imaging optics <NUM> as such are known from the prior art and thus not further described herein. It should be noted that parts of the imaging optics <NUM> may also be located outside the housing <NUM>.

As can be seen from <FIG>, a first fan assembly <NUM> is arranged on a first upper side of the sample chamber <NUM> for blowing atmosphere into the sample chamber <NUM> through a first opening <NUM> arranged in a first side wall <NUM> of the sample chamber <NUM>. As can be seen, the first opening <NUM> receives two fans for blowing atmosphere into the sample chamber <NUM>. The opening <NUM> is formed to receive a first filter system <NUM> which may be a filter extending through the entire opening <NUM> as shown in <FIG>. It is, however, also possible to provide single openings for each of the fans of the first fan assembly <NUM>, and to optionally arrange filters in these openings.

A plurality of second openings <NUM> are arranged on a second lower side of the sample chamber <NUM> in a second side wall <NUM> for allowing atmosphere from inside the sample chamber <NUM> to exit the sample chamber (also called "exit openings"). In this embodiment, a number of second exit openings <NUM> are arranged along a longer edge and a shorter edge of the second side wall <NUM> as shown in <FIG>.

In such an embodiment, when the first fan assembly <NUM> is activated, a directed flow of atmosphere from the upper side of the sample chamber down to the exit openings <NUM> in the lower side wall <NUM> is generated. Preferably, the directed flow of atmosphere is a laminar flow as will be further described below.

Atmosphere escaping from the interior of the sample chamber <NUM> on its lower side passes through the interior of the microscope housing <NUM> and is sucked in by the first fan assembly <NUM> and again blown into the sample chamber <NUM>. Thus, a steady flow of atmosphere can be created. Further features, options and advantages are described in connection with the further embodiments below.

<FIG> shows a similar embodiment of a sample chamber <NUM> as <FIG>. While <FIG> is a perspective view, <FIG> shows an embodiment as viewed from the front. In this embodiment, the first opening <NUM> is formed into the upper side wall <NUM> of the sample chamber <NUM> on the upper side <NUM>. The opening <NUM> receives a first filter system <NUM> which may be a filter extending through the opening <NUM> as shown in <FIG>. The first fan assembly <NUM>, again comprising two fans, is arranged in the first opening <NUM> of the first side wall <NUM> such that atmosphere blown into the sample chamber <NUM> passes through the filter system <NUM>. The filter system <NUM> cleans the atmosphere from any particles, like dust, dirt and/or germs.

Second openings (not shown in <FIG>) are arranged opposite the first side <NUM> of the sample chamber <NUM> on the second side <NUM>. With such an arrangement, a laminar flow <NUM> as indicated by the arrows can be generated.

Further features, options and advantages are described in connection with the further embodiments below.

<FIG> shows a preferred embodiment similar to that of <FIG> and <FIG> including a second fan assembly <NUM> arranged on the second side <NUM> of the sample chamber <NUM>, in this case, below the second side wall <NUM>. Regarding the first fan assembly <NUM> reference is made to <FIG>. The second fan assembly <NUM> includes one single fan for sucking in atmosphere flowing through the at least one second opening <NUM> arranged on the second side <NUM> in the second side wall <NUM> of the sample chamber <NUM>. Thus, the second fan assembly <NUM> supports circulation of atmosphere through the inside of the microscope housing <NUM> and through the inside of the sample chamber <NUM>. A control unit <NUM> is arranged inside the housing <NUM> for adjusting the powers of the first and second fan assemblies <NUM>, <NUM> for generating an optimal, particularly laminar flow through the sample chamber <NUM>. The control unit <NUM> may also fulfill additional tasks, e.g. in connection with the operation of the microscope <NUM>.

As can be seen from <FIG>, a front door <NUM> for accessing the sample chamber <NUM> is arranged laterally of the first (upper) side wall <NUM> and laterally of the second (lower) side wall <NUM> of the sample chamber <NUM>. Other or additional doors may be provided as desired. However, as will be explained further below in connection with <FIG>, it is mostly preferred to provide access into the sample chamber <NUM> through a door <NUM>, the surface normal of the closed door <NUM> being essentially perpendicular to the direction of flow <NUM> through the sample chamber <NUM>.

<FIG> shows yet another embodiment of a microscope <NUM> having an incubated sample chamber <NUM>. This embodiment is very similar to the one described above in connection with <FIG> such that in the following only differentiating or additional features are discussed. It should be noted that distinguishing and/or additional features among different embodiments may be combined to new embodiments still within the scope of the present inventive concept as defined in the appended claims. The embodiment of <FIG> shows an incubation control unit <NUM> for controlling and adjusting parameters of the incubation atmosphere circulating between the interior of the sample chamber and the outside of the sample chamber within the microscope housing <NUM> as indicated by the arrows.

Suitable incubation atmospheres comprise air with a predefined content of H<NUM>O (relative humidity) and a predefined content of CO<NUM> (carbon dioxide). It is also desirable to conduct hypoxia experiments with a deficiency of oxygen in the atmosphere. Typically, the temperature of the incubation atmosphere can be set in a range between ambient temperature up to <NUM>° C, the CO<NUM>-range is set between <NUM> to <NUM>%, and the O<NUM>-range is between <NUM> to <NUM>%. The humidity must be balanced to ensure that potential condensation is avoided or at least does not harm neither the microscope components nor the sample <NUM> itself. It is preferred to control at least the temperature, the humidity and the CO<NUM>-content on its own. In hypoxia experiments, the O<NUM>-content is controlled by introduction of N<NUM> (nitrogen). These parameters of the incubation atmosphere can be controlled and adjusted by the incubation control unit <NUM>. In order to control the above parameters, it is preferred to arrange corresponding sensors (not shown) in the sample chamber <NUM> and/or inside the microscope housing <NUM> and/or at the microscope stage <NUM>, preferably close to the sample <NUM>.

As further shown in <FIG>, a third filter system <NUM> is arranged at an opening or leak <NUM> of the microscope housing <NUM>. Such an opening/leak <NUM> may allow fresh air from outside the microscope <NUM> to be conducted into the inside of the microscope housing <NUM>. Such air is filtered by a third filter system <NUM> and sucked into the second fan assembly <NUM> as shown by the arrow <NUM>.

As already noted above, again the control unit <NUM> of the embodiment of <FIG> may be used to regulate the power of the second fan assembly <NUM> in order to control its suction pressure. Control unit <NUM> may be connected to the incubation control unit <NUM> for best results in this regard.

<FIG> shows yet another embodiment which mainly corresponds to the one of <FIG>. In <FIG>, a control unit <NUM> as already discussed above, is arranged inside the microscope housing <NUM> together with an incubation control unit <NUM>. <FIG> shows a perspective view showing the distribution of the second (exit) openings <NUM> along the two edges of the lower side wall <NUM>. As can be seen from <FIG>, a laminar flow <NUM> is created, the laminar flow <NUM> acting as a shield or curtain around one side of the microscope stage <NUM> (see also <FIG>), the shield/curtain of atmosphere preventing intrusion of particles including germs into the sample chamber, particularly onto the sample <NUM> itself, and simultaneously prevents atmosphere from inside the sample chamber to escape from the same and atmosphere from outside the sample chamber to invade the sample chamber.

This effect is more clearly illustrated in <FIG> showing a user's arm <NUM> entering the sample chamber <NUM> through the opened side door <NUM>. As can be seen from <FIG>, the laminar flow <NUM> is only interrupted in a small region around the user's arm <NUM> such that the remaining flow <NUM> of atmosphere still acts as a protective shield. Further, any contamination brought in by the user's arm <NUM> can be entrained by the flow <NUM> of atmosphere and transported to the exit openings <NUM> in the lower side wall of the sample chamber <NUM>. Apart from that, the embodiment of <FIG> corresponds to any one of the previous embodiments of <FIG> and can be combined with one or more features of those embodiments.

Finally, <FIG> shows a flow chart of method steps S1 to S13 for operating a microscope according to the present inventive concept.

In step S1, the microscope <NUM> is started and, at the same time, generation of the flow of atmosphere through the inside of the sample chamber <NUM> is started by activating the first fan assembly <NUM>, and optionally the second fan assembly <NUM>, of the embodiments described above. However, the method described by this embodiment is not limited to the embodiments shown in <FIG> but can be applied to other microscopes according to the present inventive concept as defined by the appended claims. In the embodiment of <FIG>, the sample chamber <NUM> is an incubated sample chamber <NUM> as, for instance, shown in <FIG> and <FIG>.

After activating the corresponding fans, also the incubation process is started (step S2) by activating the incubation control unit <NUM> (of the embodiment of <FIG>, <FIG>). During step S3 it is waited until the incubation set point is reached. A corresponding signal may be sent from the incubation control unit <NUM> to the control unit <NUM> (as shown in <FIG>). Control unit <NUM> may send a signal to a microscope user interface that the microscope is ready to be used. The front door <NUM> (see <FIG>) may then be opened by a user or by an automated mechanism (loader) either to place a sample <NUM> onto the microscope stage <NUM> (see <FIG>) or to manipulate the sample <NUM>. During this step S4 the flow of atmosphere is continued to be generated. This yields the results and advantages as discussed in connection with <FIG> as described above.

In an optional step S5 inner surfaces of the sample chamber <NUM> may be disinfected or cleaned, e.g. by alcohol, UV radiation etc., while continuing the generation of the laminar flow <NUM> inside the chamber <NUM> (see <FIG>).

In case of step S5, it is preferred to insert a sample <NUM> (manually or with a loader) into the sample chamber on the microscope stage <NUM> after step S5 in step S6. After that, the door <NUM> is closed in step S7.

After closing the door, the incubation atmosphere is equilibrated to the incubation set point of step S3. Due to the protective shield owing to the flow <NUM> of atmosphere, incubation atmosphere can be equilibrated with minimum effort (volume, energy, gases). In step S8 also microscopic imaging of the sample <NUM> is performed while the continuous flow of atmosphere is upheld.

After examination of the sample <NUM>, in step S9, the door <NUM> is opened while the continuous flow of atmosphere is upheld. Then, in step S10 the sample is unload and, optionally, another sample is loaded (manually or with an automatic loader) for further examination.

In the latter case, the method returns to optional step S7 where the door is closed to continue with steps S8 to S10.

Should no further examination be required, the method turns to step S11 where the inner surfaces of the sample chamber may again be disinfected or cleaned while a continuous flow of atmosphere may still be upheld.

Claim 1:
A microscope (<NUM>) for microscopic examination of a sample (<NUM>) comprising
an illumination optics (<NUM>) for illuminating the sample (<NUM>),
an imaging optics (<NUM>) for imaging the sample (<NUM>),
a sample chamber (<NUM>) for receiving the sample (<NUM>), the sample chamber (<NUM>) having a door (<NUM>) providing access into the sample chamber,
a first fan assembly (<NUM>) arranged on a first side (<NUM>) of the sample chamber (<NUM>) for blowing atmosphere into the sample chamber, in a first alternative, or for draining atmosphere out of the sample chamber, in a second alternative, through at least one first opening (<NUM>) arranged on the first side (<NUM>) in a first side wall (<NUM>) of the sample chamber, and
at least one second opening (<NUM>) arranged on a second side (<NUM>) in a second side wall (<NUM>) of the sample chamber (<NUM>) for allowing atmosphere from inside the sample chamber (<NUM>) to exit the sample chamber, in the first alternative, or for allowing atmosphere from outside the sample chamber (<NUM>) to enter the sample chamber, in the second alternative,
characterised in that
the first side (<NUM>) is a topside, and the second side (<NUM>) is a bottom side of the sample chamber (<NUM>), the first side wall (<NUM>) being a topside wall and the second side wall (<NUM>) being a bottom side wall of the sample chamber (<NUM>).