Improved system for filter CUBE exchange

Abstract

Rotationally mounted filter cube exchange systems improve locational and rotational accuracy. These systems can be easier and faster to use while eliminating stack-up errors, Abbé errors, and other common issues with conventional linearly-arranged filter cube exchange systems. Rotational filter cube exchange systems can also produce less wear on motors used therein, and be used to more accurately and quickly characterize samples.

Description

[0001] IMPROVED SYSTEM FOR FILTER CUBE EXCHANGE

[0002] Cross-Reference To Related Applications

[0003] This application is being filed as a PCT International application and claims the benefit of and priority to U.S. Provisional Application Nos. 63 / 677,847, filed July 31, 2024, and 63 / 707,977, filed October 16, 2024, the disclosures of which are incorporated herein by reference in their entirety.

[0004] Background

[0005] Optical filter cube exchange systems are utilized in various scientific and industrial applications to achieve precise control over light wavelengths and filtering. These systems allow for the rapid exchange of filters within an unchanged optical beam path, enabling users to adapt their setups for different imaging or data acquisition requirements.

[0006] One common application of filter cube exchange systems is in the screening of fluorescently labeled samples. By automatically switching between different filter sets and imaging channels, these systems enhance throughput and efficiency, enabling quick analysis of one or more samples that contain a variety of fluorophores. Additionally, in confocal microscopy, filter cube exchange systems play a role in selecting specific excitation and emission wavelengths. This selection helps reduce or eliminate out-of- focus light, resulting in clear and high-resolution images.

[0007] Typically, optical filter cube exchange systems incorporate a stack of filter cubes arranged side by side. The stack can be repositioned along the optical beam path to align the desired filter cube. However, using a linear drive mechanism for moving the stack may introduce some inaccuracies in cube placement. These inaccuracies can arise due to normal manufacturing tolerances as well as potential Abbe error resulting from motion irregularities in the drive system.

[0008] To improve performance and accuracy, manufacturers of filter cube exchange systems continually work to minimize these tolerances and improve the precision of the drive mechanisms. By doing so, they aim to provide users with reliable and repeatable filter exchange capabilities while maintaining the integrity of the optical path and achieving high-quality imaging or data acquisition results.

[0009] Summary

[0010] According to an embodiment, a filter cube includes an emission filter, an excitation filter, and a dichroic mirror arranged along an expected light path between the emission filter and the excitation filter, such that the dichroic mirror is arranged along a plane that intersects a center of mass of the filter cube. A mechanical coupling is arranged along the plane, and a magnetic coupling that is arranged at a distance from the plane.

[0011] The mechanical coupling can include at least three mechanical coupling features. The magnetic coupling can include at least two magnetic coupling features. The emission filter can be one of a high-pass filter, a low-pass filter, and a band-pass filter. The excitation filter can be one of a high-pass filter, a low-pass filter, and a band-pass filter. The dichroic mirror can be selected to reflect light that is transmitted by the excitation filter and transmit light that is transmitted by the emission filter.

[0012] According to another embodiment, an optical filter cube exchange system comprising a motor, a table coupled to the motor such that the motor causes a rotational movement of the table, and optical filter cubes mechanically coupled to the table. The table and the optical filter cubes are arranged such that each optical filter cube can be arranged along an optical axis at a corresponding rotational movement position of the table.

[0013] The table can include mechanical coupling features and magnetic coupling features. The table can define a plane, and the mechanical coupling features and the magnetic coupling features can be arranged to retain the plurality of optical filter cubes such that a center of mass of each of the plurality of filter cubes is substantially in the plane. The optical filter cube exchange system of claim 10, wherein each of the plurality of filter cubes comprises a dichroic mirror, and each of the dichroic mirrors is substantially in the plane. The optical filter cubes can be coupled to the table in an arrangement such that rotation of the table by the motor causes a force on each of the filter cubes along the plane. Each of the optical filter cubes can include an emission filter that is one of a high-pass filter, a low-pass filter, and a band-pass filter; an excitation filter that is one of a high-pass filter, a low-pass filter, and a band-pass filter; and a dichroic mirror. The dichroic mirror of each optical filter cube can be selected to reflect light that is transmitted by the corresponding excitation filter and transmit light that is transmitted by the corresponding emission filter. Each of the mechanical coupling features can have a T-shaped component.

[0014] According to another embodiment, a mounting system includes a table defining a plane, mechanical coupling features arranged at a perimeter of the table on the plane, and magnetic coupling features arranged to cooperate with a corresponding one of the plurality of mechanical coupling features to retain a filter cube.

[0015] The magnetic coupling features can be arranged at a distance from the plane. A motor can be used to rotate the table within the plane. Each of the mechanical coupling features can include a T-shaped component. The magnetic coupling features can be arranged to cooperate with the corresponding plurality of mechanical coupling features to retain the filter cube such that a center of mass of the filter cube is substantially in the plane. The mechanical coupling features and the plurality of magnetic coupling features can be configured to cooperate to retain a plurality of filter cubes.

[0016] Brief Description of the Figures

[0017] Aspects and advantages of the embodiments provided herein are described with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the drawings, reference numbers may be re-used to indicate correspondence between referenced elements. The drawings are provided to illustrate example embodiments described herein and are not intended to limit the scope of the disclosure.

[0018] FIG. 1 is a perspective view of a linear filter cube exchange system.

[0019] FIG. 2 is a cutaway view of a filter cube usable in the system of FIG. 1.

[0020] FIG. 3 is a side view of the filter cube of FIG. 2.

[0021] FIG. 4 is a perspective view of a rotary filter cube exchange system.

[0022] FIG. 5 is a cutaway view of the rotary filter cube exchange system of FIG. 4, showing only the filter cubes and mounting table.

[0023] FIG. 6 is a front view of the filter cubes and mounting table of FIG. 5, depicting the table plane thereof.

[0024] FIG. 7 shows the filter cubes and mounting table of FIGS. 5 and 6, with one filter cube removed to depict the mounting system thereof. FIG. 8 is a partial detail view of a rotary filter cube exchange system such as that of FIGS. 4-7, with all of the portions of a filter cube except for a dichroic mirror removed.

[0025] FIG. 9 is a detailed view of a filter cube including a magnetic mount.

[0026] FIG. 10 is a right side view of a filter cube for use in the system of FIG. 4.

[0027] FIG. 11 is a left side view of the filter cube of FIG. 10.

[0028] While various embodiments are amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the claimed inventions to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter as defined by the claims.

[0029] Detailed Description

[0030] In microscopes it is advantageous to have the capability to exchange optical elements in order to produce the desired image qualities. Many microscopes incorporate epi filter cubes (also referred to herein simply as “filter cubes”) which may include optical components such as dichroic mirrors and other types of filters or optical elements to modify the propagated light. In sophisticated or automated microscopes multiple filter cubes may be used to address different imaging requirements. These filter cubes must be aligned accurately and repeatably to maintain image positioning and quality. This is a challenge because of the number of mechanical components that must be assembled in order to produce the multiple filter cubes and the exchange mechanism.

[0031] FIG. 1 depicts a linear filter cube exchange system 100. FIG. 1 shows a filter cube stack holder 102 coupled to a track 104. The filter cube stack holder 102 can be moved along the track 104 with the use of a motor 106. Movement of the filter cube stack holder 102 along the track 104 causes a corresponding movement of the filter cube stack 108. Filter cube stack 108 is made up of a set of filter cubes, shown in FIG. 1 as filter cube 110. In FIG. 1 , each filter cube 110 is one of five filter cubes that make up the filter cube stack 108, but in alternative embodiments there can be any number of filter cubes 110 that make up a filter cube stack 108.

[0032] Each filter cube 110 of the filter cube stack 108 houses a set of optical elements that produce desired effects on the image. Specific filter cubes 110 are called out as filter cube 110A, filter cube 11OB, and filter cube 11OC. However, much of the discussion herein is not specific to any particular filter cube 110.

[0033] Filter cubes 110 can each include an emission filter and an excitation filter that are arranged along optical pathways determined by a beamsplitter such as a dichroic mirror, as described in more detail below with respect to FIG. 2.

[0034] As shown in FIG. 1, filter cube stack 108 is typically attached to the motor 106, which can be a linear drive motor. Motor 106 can be used to insert the filter cube 110 in an optical path (not shown). An incident optical signal received by a filter cube 110 (e.g., any of the filter cube 110A, filter cube 110B, filter cube 110C, or any number of other filter cubes that make up the filter cube stack 108) can be received, filtered and internally reflected or transmitted within the filter cube 110, and emitted. Linear drives can place the filter cube 110 inexactly, however, subject to normal tolerances as well as Abbe error incurred by the nature of the drive motion inaccuracies. These normal tolerances can include, for example, the accuracy of positioning of the filter cube 110 within the filter cube stack 108, and the accuracy of positioning of the filter cube stack holder 102 by the motor 106 along the track 104.

[0035] It is often the case that a particular type of sample analysis or other use of the filter cube exchange system 100 will use a different set of filter cubes 110 than a different type of sample analysis. Therefore, depending on the samples being tested and the types of sample responses that are being detected, it is often desirable to replace filter cubes 110 to include a specific set thereof.

[0036] A filter cube stack 108 typically includes a set of filter cubes 110 that are arranged in a row. This arrangement means that some errors, such as those caused by thermal expansion or contraction, are compounded along the length of the filter cube stack 108, with higher error in positioning at the third filter cube than at the second filter cube in the row, and higher error in positioning at the second filter cube than at the first filter cube in the row.

[0037] FIG. 1 also shows the potential for Abbe errors to be introduced. Abbe error refers to a linear error caused by the combination of an underlying angular error and a dimensional offset between the object being measured and the accuracy determining element. In FIG. 1, the motor 106 provides a desired position and is therefore the accuracy determining element and nominally determines the precision of the position of the filter cube stack holder 102 and by extension all of the filter cubes 110 (including specific filter cubes 110A, 11OB, 1 IOC, as well as any other filter cubes in the filter cube stack 108).

[0038] Angular error can also be introduced as the filter cubes 110 (e.g., 110A, 110B, 110C) are arranged into a filter cube stack 108 in a filter cube stack holder 102. For example, the filter cubes 110 (e.g., 110A, 110B, 1 IOC, or others in the filter cube stack 108) can be affixed to the filter cube stack holder 102 at an angle that deviates from intended if the filter cubes 110 that make up the filter cube stack 108 are not all perfectly aligned with one another and with the filter cube stack holder 102. Furthermore, additional angle error can be introduced during use, as linear displacement of filter cube stack holder 102. Because the center of mass of each of the filter cubes 110 is higher (in the view shown in FIG. 1) than the filter cube stack holder 102 to which they are attached, movement of the filter cube stack holder 102 necessarily applies some torque to each of the filter cubes 110 that can cause small movements and therefore angular errors in the optical components therein, causing Abbe error.

[0039] FIG. 2 shows a filter cube 210, which is usable in a variety of filter cube exchange systems. For example, the filter cube 210 of FIG. 2 could be used as a filter cube 110 of FIG. 1, including but not limited to any of the first, second, and third filter cubes (110A, 110B, and 110C) of FIG. 1.

[0040] Filter cube 210 includes an excitation filter 212, a dichroic mirror 214, and an emission filter 216. While various types of filter cubes are used in different operating environments and for different purposes, this arrangement is common.

[0041] Throughout the following description, some standard terminology is used to refer to the light traveling to, from, and within filter cube 210 during use. Excitation light comes from an excitation source, and can be filtered, reflected, or otherwise directed by the filter cube 210 until it arrives at a sample. Sample light refers to the light that emanates from the sample upon illumination by the excitation light. For example, sample light can be reflected / emitted from the sample. In one example, sample light can be light that is fluoresced by the sample in response to illumination by the excitation light.

[0042] In use, excitation light is received at excitation filter 212 from the region shown on the left side of the page. The light received at excitation filter 212 can come from any of a variety of sources, such as a laser, LED, or the like. The light can include a broad spectrum of wavelengths. The excitation light is filtered at excitation filter 212 to exclude light that is not at a desired wavelength. To accomplish this, excitation filter 212 can be, for example, a band-pass filter, a high-pass filter, a low-pass filter, or a combination of filters or other optical components that cooperate to permit only certain wavelengths of interest.

[0043] The light that has passed through excitation filter 212 is received at dichroic mirror 214. In other embodiments, dichroic mirror 214 could be replaced with some other beamsplitter that selectively handles light having different wavelengths. Dichroic mirror 214 is chosen to be reflective in at least some of the wavelength or wavelengths that are transmitted by the excitation filter 212. Thus the dichroic mirror 214 acts to reflect the light towards the aperture opposite from emission filter 216.

[0044] The excitation filter 212 and the dichroic mirror 214 therefore provide criteria for which light is routed out of the filter cube 210 and to a sample. Often there is a desired wavelength or set of wavelengths that is used with a corresponding filter cube 210. For example, a filter cube 210 can be tuned to send wavelengths that excite a particular fluorophore in a sample, without using wavelengths that would merely add signal noise or excite other fluorophores. Excitation filter 212 excludes undesirable wavelengths, while dichroic mirror 214 reflects desirable ones. Only light that is permitted by excitation filter 212 and reflected by the dichroic mirror 214 is directed to the sample (not shown, off the top of the page).

[0045] Excitation light that passes through excitation filter 212 and is reflected by dichroic mirror 214 induces some fluorescence, reflection, refraction, or other signal to emanate from the sample. That signal is received at the filter cube 210 from the sample is received along the same path that the excitation light was routed to the sample; that is, light from the top of the page travels downwards until it arrives at dichroic mirror 214.

[0046] Sample light that arrives at dichroic mirror 214 can have a variety of wavelengths. Fluoresced sample light can have a higher wavelength (such as in the case of typical fluorescence) or a lower wavelength (such as in the case of two-photon excitation) than the excitation light. Reflected sample light can have the same wavelength as the excitation light, or can have a higher wavelength due to Raman shift. Some wavelengths may be reflected more or less than other wavelengths, based on the absorption, reflection, and transmission characteristics of a sample, which can vary as a function of wavelength.

[0047] Dichroic mirror 214 reflects away the sample light that has the same wavelength as the excitation light because, as described above, it is reflective in that wavelength band. Thus only wavelength-shifted light may be transmitted. In some embodiments, not every wavelength that is transmitted by dichroic mirror 214 is of interest. For example, a particular fluorescent wavelength associated with a particular fluorophore may be of interest. Similarly, a particular wavelength associated with a particular Raman shift caused by a specific type of chemical bond in a sample may be of interest. Emission filter 216 can be used to remove other signal(s). Thus, the light leaving the emission filter 216 (that is, towards the bottom of the page in FIG. 2) will have passed through dichroic mirror 214 and emission filter 216, each of which removes some undesirable wavelengths of light to leave the ones that are of interest for sample analysis.

[0048] As can be seen from FIG. 2, in the event that the filter cube 210 is off alignment there are compounding positional errors in the light that is routed by that component. For example, a positioning error in dichroic mirror 214 would cause light to be directed to the wrong location. A rotational error in the placement of dichroic mirror 214 not only sends emission light off at the wrong angle, but also can refract sample light both at dichroic mirror 214 and at emission filter 216. Accordingly, the positioning and the rotational orientation of filter cube 210 is important.

[0049] FIG. 3 shows an exterior of a filter cube 310, which is similar to those described above with respect to FIGS. 1 and 2. In particular, FIG. 3 shows a notch 318 which is a mechanical coupling feature for attaching the filter cube 310 to a filter cube holder (not shown in this drawing, but see e.g. filter cube stack holder 102 of FIG. 1).

[0050] A notch 318 is a typical way to mechanically engage the filter cube 310 in the correct position on a filter cube holder, which can have other mechanical features to promote proper positioning. For example, as shown in FIG. 1 the filter cube stack holder 102 had dimensions and mechanical features that permitted the filter cubes 110 therein to be arranged side by side and hold one another in place. However, each of these systems will necessarily permit some amount of movement prior to mechanical interference with the structures holding the filter cubes in place. Furthermore, as described above, each of these systems exert forces on the filter cubes during movement or thermal expansion or contraction that promote movement of the filter cubes.

[0051] In sum, the filter cube arrangement shown in FIG. 1 is susceptible to drive angularity, Abbe error, locational errors, rotational errors, motor repeatability errors in position, and insertion repeatability errors in placing the filter cubes into a corresponding mechanical friction-fit housing or tray. FIG. 4 shows an optical filter cube exchange system 400 that reduces or eliminates the aforementioned errors in positioning and angling of filter cubes. Optical filter cube exchange system 400 includes similar components to those described above with respect to FIGS. 1, 2, and 3, but these components are arranged in different ways. To the extent that like parts are used in the rotary systems described below, the same reference numbers from the linear systems described above are used with iterations by multiples of 100. Thus filter cubes 410, for example, are substantially the same as filter cubes 110, 210, and 10, unless otherwise noted below, and descriptions of those components is not repeated where doing so would be redundant.

[0052] Optical filter cube exchange system 400 includes a table 402, a motor 406, a mechanical coupling 418, and a magnetic coupling 420. Additionally, as briefly described above, optical filter cube exchange system 400 includes a set of six filter cubes 410 that are arranged about a perimeter of the table 402. The filter cubes 410 are held into a fixed position by the mechanical couplings 418 and magnetic couplings 420.

[0053] As shown in FIG. 4, motor 406 can rotate the table 402, and by extension the filter cubes 410. Therefore, to use a particular filter cube 410 with a sample, the filter cube 410 would be rotated into the beam path to direct excitation light towards the sample, and collect the sample light after passing through an emission filter, as described above with respect to FIG. 2.

[0054] Unlike the linear filter cube exchange systems, however, several of the errors in positioning (both locationally and rotationally) are reduced or eliminated, or at least made uniform across the filter cubes 410. For example, thermal expansion and contraction of table 402 would affect all of the filter cubes 410 identically. The table 402 can fix and align the filter cubes 410 relative to the desired optical axis. Table 402 can be machined to a high accuracy.

[0055] A low cost but high accuracy stepper motor is used as the motor 406. The motor 406 is designed with mounting hub, which is accurately bonded in place, assuring tight angular and locational control. In this arrangement there are no external or mechanical elements bearing on the motor, thereby no frictional or external forces on the rotary table 402, allowing the motor 406 motion to be precise and highly repeatable.

[0056] Table 402 can be coupled to the motor 406 such that the motor 406 causes a rotational movement of the table 402. This rotational movement can be used to provide a desired filter cube 410 along the optical axis, and the rotational movement itself should not cause displacement of the filter cubes 410 relative to the table 402. That is, the table 402 and the filter cubes 410 move together and the rotational movement of the table 402 caused by the motor 406 does not tend to push any of the filter cubes 410 out of their alignment with the table 402. As a result, the table 402 and all of the filter cubes 410 arranged thereon can be rotated, and the rotational movement of the table 402 caused by actuation of the motor 406 can be used to position a desired one of the filter cubes 410 along the optical axis, without losing alignment of filter cubes 410.

[0057] In addition to locational position, filter cubes 410 are held in a way that reduces the potential for rotational errors, as shown in more detail in FIG. 5. Rotational errors can cause significant translations and directional changes to light that passes between the sample, excitation filter 512, and emission filter 516 shown in FIG. 5.

[0058] FIG. 5 shows an alternative optical filter cube exchange system 500, with more detail of various components of interest therein. In particular, each of the dichroic mirrors 514 of the filter cubes 510 in the optical filter cube exchange system 500 is coplanar with the table 502. The mechanical couplings 518 and magnetic couplings 520 are provided to prevent rotation generally. While a single mechanical coupling 518 and a single magnetic coupling 520 is shown in FIG. 5, there may be any number of such components in alternative embodiments. In some embodiments, as described below, there can be one mechanical coupling 518 on each side of any given filter cube 510 as well as one on the back of the filter cube 510, or three total mechanical couplings 518.

[0059] When a different filter cube 510 is desired, table 502 can be rotated to place a new filter cube 510 in the optical pathway. When this happens, because the dichroic mirror 514 is substantially in-plane with the table 502, there is no torque applied to the dichroic mirror 514 that would pull that component out of plane.

[0060] It should be understood that dichroic mirror 514 has some thickness, manufacturing tolerance, and other imperfections in manufacture or positioning such that it will not always be exactly in-plane with the table 502. As used throughout this specification and the claims, “substantially” in plane refers to a system that is nominally designed to maintain these components in-plane with one another, even if they may vary in some instances. A substantially in-plane system is one in which the contribution to locational or rotational errors that is caused by the out-of-plane condition is negligible. In many embodiments, the magnetic coupling 520 will be arranged at a distance from the plane. This terminology is used to indicate that the magnetic coupling is substantially out-of-plane from the table (e.g., table 502). Including the magnetic coupling 520 arranged at a distance from the plane provides counteracting forces that prevent movement of the dichroic mirror 514 relative to the table 502 in multiple degrees of freedom.

[0061] FIG. 6 shows the table plane P, shown as a dashed line, in a front view of filter cube exchange system 600. FIG. 6 also shows how mechanical couplings 618 are provided that hold the filter cubes 610 in place substantially in-plane with the table plane P, while magnetic couplings 620 are provided that are out of plane with table plane P.

[0062] FIG. 6 shows a plurality of mechanical coupling features 618 as well as a plurality of magnetic coupling features 620. It should be understood that in alternative embodiments, there could be relatively more or fewer mechanical coupling features 618 or magnetic coupling features 620 used in other similar systems. For example, mechanical couplings 618 or magnetic couplings 620 could be used on either side (or both) of the filter cubes 610, or at the back thereof, which is to say the radially innermost portion of table 602 where filter cube 610 is adjacent. In one embodiment, there can be three mechanical coupling features; one at each of the sides of the filter cube 610 and one at the back thereof. The mechanical coupling features 618 and the magnetic coupling features 620 can each, independently or in coordination with one another, be used to retain the optical filter cubes 610 such that a center of mass of each of the optical filter cubes 610 is substantially in the plane P.

[0063] FIG. 7 shows a version of a filter cube exchange system 700 that is substantially similar to the ones shown in FIGS. 5 and 6, with one of the filter cubes removed. Removal of one of the filter cubes facilitates depiction of the mechanical coupling 718 and the magnetic coupling 720. As shown in FIG. 7, the mechanical coupling is a T-shaped component that has a counterpart receiving structure in the filter cube. There can be any number of shapes or other fastener types used in other embodiments.

[0064] The magnetic coupling 720 is shown as a circular magnet attached below the table 702. Similar to the mechanical coupling 718, magnetic coupling 720 has a counterpart magnetically susceptible or magnetic element at a region of the filter cubes used with that system. These magnetic couplings 720 and corresponding magnetically susceptible or magnetic elements of the filter cubes themselves are oriented to push or pull the filter cubes angularly and positionally to the desired location and rotational position. Magnetic couplings 720 are shown in FIG. 7 as having a north pole (indicated with an “N”) or a south pole (indicated with an “S”). As shown in FIG. 7, there may be two magnetic couplings 720 associated with any particular filter cube. The removed filter cube from the arrangement of FIG. 7 would be acted upon primarily by the two magnetic couplings 720 (labeled with “N” and “S”), one on each side thereof. In embodiments, the magnetic coupling 720 includes at least two magnetic coupling features as shown in FIG. 7, though in alternative embodiments there could be any number of magnetic coupling features.

[0065] FIG. 8 is a partial view of a filter cube exchange system 800, with all elements of the filter cube in the center of the view removed but for the dichroic mirror 814. As shown in FIG. 8, the dichroic mirror 814 is substantially in-plane with the table 802.

[0066] The orientation and fixing of the dichroic mirror 814 of the filter cube to the table provides for the reduction of typical tolerance stackups associated with other methods where the filter cube - rather than the mirror - is indexed against the drive elements. The table is therefore oriented at 45 degrees to the optical axis. The lightweight rotating components are optimized for rapid rotary motion relative to a typical linear stage.

[0067] Mechanical coupling features 818 and magnetic coupling features 820 stabilize dichroic mirror 814. As noted above, the elements of the filter cube that contains dichroic mirror 814 are removed in FIG. 8, and those other elements can include counterparts to the mechanical coupling features 818 and magnetic coupling features 820 of the table 802 that are shown in FIG. 8.

[0068] FIG. 9 shows a filter cube 910 that is usable with the rotational filter cube exchange systems described herein. Filter cube 910 includes an excitation filter 912, dichroic mirror 914, and emission filter 916 that are substantially the same as those described above with respect to other drawings. Additionally, FIG. 9 shows counterpart magnetic coupling 924A and counterpart magnetic coupling 924B. These elements engage with the magnetic couplings of the table (see, e.g., discussion of magnetic coupling 520, 620, and 720, above) to provide stable locational and rotational positioning of the filter cube 910.

[0069] Similarly, FIG. 9 shows counterpart mechanical coupling 922. Counterpart mechanical coupling 922 can engage with the corresponding mechanical coupling of the table (see, e.g., discussion of mechanical couplings 518, 618, and 718, above). In concert with the magnetic couplings described above, accuracy and stability of the locational and rotational positioning of the filter cubes 910 is improved.

[0070] FIG. 10 shows a filter cube 1010 with the table plane P indicated therein. As described above with respect to FIG. 8, the table plane P runs diagonally through the filter cube 1010, which is to say that the cube is oriented at a 45 degree angle relative to the table that defines the table plane P. Light enters at excitation filter 1012 at a 45 degree angle above the table plane P and is directed towards through an emission filter 1016 the sample at a 45 degree angle below the table plane P, as shown in this figure.

[0071] Filter cube 1010 is held in position by a combination of features, at least including the mechanical coupling 1024 shown in FIG. 10 arranged along the table plane P. FIG. 10 depicts how while there are elements of a mechanical coupling 1024 that are substantially in-plane with the table plane P, the mechanical coupling 1024 can also extend off of the table plane P to limit the degrees of freedom of movement of the filter cube 1010.

[0072] FIG. 11 shows a filter cube 1110 and depicts the side thereof, with the counterpart mechanical coupling 1122 and counterpart magnetic coupling 1124 shown thereon. Similar to FIG. 10, light enters at emission filter 1116 and is at least partially reflected internal to the filter cube 1110 to be routed through excitation filter 1112.

[0073] Additionally, table plane P is again indicated across the filter cube 1110. The complex magnetic force vector pushes the filter cube 1110 to align substantially to the table plane P and the various mechanical coupling surfaces (two stops and wall edge) for alignment. As described above with respect to FIG. 6, in embodiments there can be exactly three mechanical coupling surfaces or features; two stops and a wall edge. In other embodiments, various other mechanical coupling features or surfaces can be used and there can be any number of mechanical couplings 1122.

[0074] Center of mass 1126 is indicated for the filter cube 1110, as is centripetal force vector 1128 that would result from rotation of the filter cube 1110 within the table plane (see FIG. 4). As shown in FIG. 11, the counterpart mechanical couplings 1122 and magnetic couplings 1124 both act with the centripetal force vector 1128 to fix the cube in place. In fact, filter cubes 1110 are engineered so that the centripetal forces generated by rotation aids in the retention of the cubes.

[0075] As shown in FIG. 11, center of mass 1126 is arranged along the plane P, or substantially in the plane. Furthermore, as described above with respect to FIGS. 5, 6, and 8, the dichroic mirror (e.g., dichroic mirror 514 of FIG. 5, and dichroic mirror 814 of FIG. 8) are also arranged along the plane P. In other words, the dichroic mirror (514, 814) is arranged substantially in-plane with the center of mass (1126) of each filter cube, along the plane P defined by the table (e.g., 502, 602, 802).

[0076] The rotation design described herein provides users with an improved ability to change filter sets in filter cube systems without incurring optical alignment errors common other implementations. Additionally, the filter cubes in these systems are all independently positioned from one another on an easily accessible table, which improves speed of filter changes. The magnetic mounting elements described herein reduce misalignment errors caused by filter changes. The motor can experience reduced wear compared to other drive methods that have conventionally been used.

[0077] It should be understood that while the disclosure herein relates to filter cubes, other optical components could be used in other embodiments to accomplish similar reductions in errors and improvements in repeatability.

[0078] This disclosure described some examples of the present technology with reference to the accompanying drawings, in which only some of the possible examples were shown. Other aspects can, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein. Rather, these examples were provided so that this disclosure was thorough and complete and fully conveyed the scope of the possible examples to those skilled in the art.

[0079] Although specific examples were described herein, the scope of the technology is not limited to those specific examples. One skilled in the art will recognize other examples or improvements that are within the scope of the present technology. Therefore, the specific structure, acts, or media are disclosed only as illustrative examples. Examples according to the technology may also combine elements or components of those that are disclosed in general but not expressly exemplified in combination, unless otherwise stated herein. The scope of the technology is defined by the following claims and any equivalents therein.

[0080] ASPECTS

[0081] Aspect 1. A filter cube comprising: an emission filter; an excitation filter; a dichroic mirror arranged along an expected light path between the emission filter and the excitation filter, the dichroic mirror arranged along a plane that intersects a center of mass of the filter cube; a mechanical coupling arranged along the plane; and a magnetic coupling that is arranged at a distance from the plane.

[0082] Aspect 2. The filter cube of aspect 1, wherein the mechanical coupling comprises at least three mechanical coupling features.

[0083] Aspect 3. The filter cube of aspect 1 or aspect 2, wherein the magnetic coupling comprises at least two magnetic coupling features.

[0084] Aspect 4. The filter cube of any preceding aspect, wherein the emission filter is one of a high-pass filter, a low-pass filter, and a band-pass filter.

[0085] Aspect 5. The filter cube of any preceding aspect, wherein the excitation filter is one of a high-pass filter, a low-pass filter, and a band-pass filter.

[0086] Aspect 6. The filter cube of any preceding aspect, wherein the dichroic mirror is selected to reflect light that is transmitted by the excitation filter and transmit light that is transmitted by the emission filter.

[0087] Aspect 7. An optical filter cube exchange system comprising: a motor; a table coupled to the motor such that the motor causes a rotational movement of the table; and a plurality of optical filter cubes mechanically coupled to the table.

[0088] Aspect 8. The optical filter cube exchange system of aspect 7, wherein the table and the plurality of optical filter cubes are arranged such that each optical filter cube of the plurality of optical filter cubes can be arranged along an optical axis at a corresponding rotational movement position of the table.

[0089] Aspect 9. The optical filter cube exchange system of aspect 7, wherein table comprises a plurality of mechanical coupling features and a plurality of magnetic coupling features.

[0090] Aspect 10. The optical filter cube exchange system of any of aspects 7-9, wherein: the table defines a plane; and the plurality of mechanical coupling features and the plurality of magnetic coupling features are arranged to retain the plurality of optical filter cubes such that a center of mass of each of the plurality of filter cubes is substantially in the plane.

[0091] Aspect 11. The optical filter cube exchange system of aspect 10, wherein each of the plurality of filter cubes comprises a dichroic mirror, and each of the dichroic mirrors is substantially in the plane.

[0092] Aspect 12. The optical filter cube exchange system of any of aspects 7-11, wherein the plurality of optical filter cubes are coupled to the table in an arrangement such that rotation of the table by the motor causes a force on each of the filter cubes along the plane.

[0093] Aspect 13. The optical filter cube exchange system of any of aspects 7-12, wherein each of the plurality of optical filter cubes comprises: an emission filter that is one of a high-pass filter, a low-pass filter, and a bandpass filter; an excitation filter that is one of a high-pass filter, a low-pass filter, and a bandpass filter; and a dichroic mirror.

[0094] Aspect 14. The optical filter cube exchange system of aspect 13, wherein the dichroic mirror of each of the plurality of optical filter cubes is selected to reflect light that is transmitted by the corresponding excitation filter and transmit light that is transmitted by the corresponding emission filter.

[0095] Aspect 15. The optical filter cube exchange system of aspect 9 or aspect 10, wherein each of the plurality of mechanical coupling features comprises a T-shaped component.

[0096] Aspect 16. A mounting system comprising: a table defining a plane; a plurality of mechanical coupling features arranged at a perimeter of the table on the plane; and a plurality of magnetic coupling features, each of the plurality of magnetic coupling features arranged to cooperate with a corresponding one of the plurality of mechanical coupling features to retain a filter cube.

[0097] Aspect 17. The mounting system of aspect 16, wherein the plurality of magnetic coupling features are arranged at a distance from the plane. Aspect 18. The mounting system of aspect 16 or aspect 17, further comprising a motor configured to rotate the table within the plane.

[0098] Aspect 19. The mounting system of any of aspects 16-18, wherein each of the plurality of mechanical coupling features comprises a T-shaped component. Aspect 20. The mounting system of any of aspects 16-19, wherein the plurality of magnetic coupling features arranged to cooperate with the corresponding plurality of mechanical coupling features to retain the filter cube such that a center of mass of the filter cube is substantially in the plane.

[0099] Aspect 21. The mounting system of any of aspects 16-20, wherein the plurality of mechanical coupling features and the plurality of magnetic coupling features are configured to cooperate to retain a plurality of filter cubes.

Claims

ClaimsWhat is claimed is:

1. A filter cube comprising: an emission filter; an excitation filter; a dichroic mirror arranged along an expected light path between the emission filter and the excitation filter, the dichroic mirror arranged along a plane that intersects a center of mass of the filter cube; a mechanical coupling arranged along the plane; and a magnetic coupling that is arranged at a distance from the plane.

2. The filter cube of claim 1, wherein the mechanical coupling comprises at least three mechanical coupling features.

3. The filter cube of claim 1 or claim 2, wherein the magnetic coupling comprises at least two magnetic coupling features.

4. The filter cube of any preceding claim, wherein the emission filter is one of a high-pass filter, a low-pass filter, and a band-pass filter.

5. The filter cube of any preceding claim, wherein the excitation filter is one of a high-pass filter, a low-pass filter, and a band-pass filter.

6. The filter cube of any preceding claim, wherein the dichroic mirror is selected to reflect light that is transmitted by the excitation filter and transmit light that is transmitted by the emission filter.

7. An optical filter cube exchange system comprising: a motor; a table coupled to the motor such that the motor causes a rotational movement of the table; anda plurality of optical filter cubes mechanically coupled to the table.

8. The optical filter cube exchange system of claim 7, wherein the table and the plurality of optical filter cubes are arranged such that each optical filter cube of the plurality of optical filter cubes can be arranged along an optical axis at a corresponding rotational movement position of the table.

9. The optical filter cube exchange system of claim 7, wherein table comprises a plurality of mechanical coupling features and a plurality of magnetic coupling features.

10. The optical filter cube exchange system of any of claims 7-9, wherein: the table defines a plane; and the plurality of mechanical coupling features and the plurality of magnetic coupling features are arranged to retain the plurality of optical filter cubes such that a center of mass of each of the plurality of filter cubes is substantially in the plane.

11. The optical filter cube exchange system of claim 10, wherein each of the plurality of filter cubes comprises a dichroic mirror, and each of the dichroic mirrors is substantially in the plane.

12. The optical filter cube exchange system of any of claims 7-11, wherein the plurality of optical filter cubes are coupled to the table in an arrangement such that rotation of the table by the motor causes a force on each of the filter cubes along the plane.

13. The optical filter cube exchange system of any of claims 7-12, wherein each of the plurality of optical filter cubes comprises: an emission filter that is one of a high-pass filter, a low-pass filter, and a bandpass filter; an excitation filter that is one of a high-pass filter, a low-pass filter, and a bandpass filter; and a dichroic mirror.

14. The optical filter cube exchange system of claim 13, wherein the dichroic mirror of each of the plurality of optical filter cubes is selected to reflect light that is transmitted by the corresponding excitation filter and transmit light that is transmitted by the corresponding emission filter.

15. The optical filter cube exchange system of claim 9 or claim 10, wherein each of the plurality of mechanical coupling features comprises a T-shaped component.

16. A mounting system comprising: a table defining a plane; a plurality of mechanical coupling features arranged at a perimeter of the table on the plane; and a plurality of magnetic coupling features, each of the plurality of magnetic coupling features arranged to cooperate with a corresponding one of the plurality of mechanical coupling features to retain a filter cube.

17. The mounting system of claim 16, wherein the plurality of magnetic coupling features are arranged at a distance from the plane.

18. The mounting system of claim 16 or claim 17, further comprising a motor configured to rotate the table within the plane.

19. The mounting system of any of claims 16-18, wherein each of the plurality of mechanical coupling features comprises a T-shaped component.

20. The mounting system of any of claims 16-19, wherein the plurality of magnetic coupling features arranged to cooperate with the corresponding plurality of mechanical coupling features to retain the filter cube such that a center of mass of the filter cube is substantially in the plane.

21. The mounting system of any of claims 16-20, wherein the plurality of mechanical coupling features and the plurality of magnetic coupling features are configured to cooperate to retain a plurality of filter cubes.

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