PRIORITY

[0001] This application claims priority to U.S. Provisional Pat. App. No. 62/448,020, entitled "Robotic Machine with Light Curtain System," filed January 19, 2017, the disclosure of which is incorporated by reference herein.

BACKGROUND

[0002] Robotic machines may incorporate one or more moving components that move in an automated fashion relative to one or more fixed components. In such systems, it may be desirable to reduce any risks associated with a human coming into contact with the one or more moving components during movement of the one or more moving components. For instance, a moving component may move within a close enough proximity to fixed component such that it may be undesirable for a human operator to position a hand or other body part between the moving component and the fixed component. It may therefore be desirable to provide a sensing system that senses the positioning of a human body part or other object within a certain field of space associated with a robotic machine.

[0003] An example of a robotic machine with a sensing system is described in U.S. Pat.

No. 6,166,371, entitled "Diffuse Reflective Light Curtain System," issued December 26, 2000, the disclosure of which is incorporated by reference herein. While the sensing system described in U.S. Pat. No. 6,166,371 may be suitable for various kinds of robotic machines, it may be beneficial to provide a further enhanced sensing system for some other kinds of robotic machines. For instance, the fixed framework of a robotic system may provide certain regions that present blind spots for a conventional light curtain sensing system, such that it may be desirable to enhance the light curtain sensing system to eliminate or otherwise address such blind spots.

[0004] While a variety of systems and methods have been made and used within robotic machines, it is believed that no one prior to the inventor(s) has made or used the technology as described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] It is believed the present invention will be better understood from the following description of certain examples taken in conjunction with the accompanying drawings, in which like reference numerals identify the same elements and in which:

[0006] FIG. 1 depicts a perspective view of an exemplary robotic machine, with a door in a closed position;

[0007] FIG. 2 depicts a perspective view of the robotic machine of FIG. 1, with the door in an open position;

[0008] FIG. 3 depicts a front elevational view of the robotic machine of FIG. 1, with the door in an open position;

[0009] FIG. 4 depicts an enlarged perspective view of the region of the robotic machine of

FIG. 1 indicated by the "FIG. 4" broken line circle in FIG. 2;

[0010] FIG. 5 depicts a perspective view of components of a light curtain system of the robotic machine of FIG. 1;

[0011] FIG. 6 depicts a top plan view of the components of the light curtain system of FIG.

5;

[0012] FIG. 7 depicts an enlarged perspective view of the region of the robotic machine of

FIG. 1 indicated by the "FIG. 7" broken line circle in FIG. 2;

[0013] FIG. 8 depicts a perspective view of the door of the robotic machine of FIG. 1;

[0014] FIG. 9 depicts a cross-sectional view of the door of FIG. 8, taken along line 9-9 of

FIG. 8; and

[0015] FIG. 10 depicts a schematic view of a controller and associated components of the robotic machine of FIG. 1. DETAILED DESCRIPTION

[0016] The following description of certain examples of the technology should not be used to limit its scope. Other examples, features, aspects, embodiments, and advantages of the technology will become apparent to those skilled in the art from the following description, which is by way of illustration, one of the best modes contemplated for carrying out the technology. As will be realized, the technology described herein is capable of other different and obvious aspects, all without departing from the technology. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not restrictive.

[0017] It is further understood that any one or more of the teachings, expressions, embodiments, examples, etc. described herein may be combined with any one or more of the other teachings, expressions, embodiments, examples, etc. that are described herein. The following-described teachings, expressions, embodiments, examples, etc. should therefore not be viewed in isolation relative to each other. Various suitable ways in which the teachings herein may be combined will be readily apparent to those of ordinary skill in the art in view of the teachings herein. Such modifications and variations are intended to be included within the scope of the claims.

[0018] I. Overview of Exemplary Robotic System

[0019] FIGS. 1-3 depicts an exemplary robotic system (10). In the present example, robotic system (10) is configured to handle various kinds of liquid in numerous ways and in a rapid and precise fashion in order to facilitate laboratory procedures. By way of example only, robotic system (10) may provide at least some of the functionality associated with a conventional Biomek® Lab Automation Workstation by Beckman Coulter, with the additional features and functionality described below. However, it should be understood that the teachings herein may be readily applied to various kinds of robotic systems, such that the invention is not limited to systems that are configured to provide automated handling of liquid in a laboratory environment.

[0020] Robotic system (10) of the present example comprises a lower enclosure (20), an upper enclosure (40), and a door (50). Upper enclosure (40) is supported atop lower enclosure (20). In the present example, upper enclosure (40) includes a set of light strips (42) that are configured to illuminate in different colors to thereby provide visual feedback to a user regarding the operational state of robotic system (10). By way of example only, light strips (42) may illuminate in a first color to indicate that robotic system (10) is currently executing a liquid handling process; in a second color to indicate that the liquid handling process is complete; and in a third color to indicate a warning condition. In addition, or in the alternative, to illuminating in different colors, light strips (42) may flash in one or more patterns to provide visual feedback indicating one or more conditions or operational states of robotic system (10). In some variations of upper enclosure (40), light strips (42) are omitted. It should therefore be understood that light strips (42) are merely optional. Moreover, it should be understood that upper enclosure (40) is merely optional. In versions of robotic system (10) where upper enclosure (40) is omitted, the top region of lower enclosure (20) may simply be open to the environment.

[0021] Lower enclosure (20) includes a plurality of columns (22, 24, 26) and panels (30,

32, 36). In particular, lower enclosure (20) includes a pair of front columns (22, 24) and a pair of rear columns (26) (though the view of one of the rear columns (26) is obscured in FIGS. 1-3). A first side panel (30) spans between a first front column (22) and one of rear columns (26); while a second side panel (32) spans between a second front column (24) and another of rear columns (26). Side panels (30, 32) are transparent in the present example, though this is merely optional. A rear panel (36) spans between both rear columns (26). While only one rear panel (36) is indicated in FIG. 3, it should be understood that more than one rear panel may be provided at the rear of lower enclosure (20). It should also be understood that more than one panel may be provided on each side of lower enclosure (20). Moreover, one or more of panels (30, 32, 36) may simply be omitted in some versions of lower enclosure (20).

[0022] Door (50) of the present example comprises a frame (52) and a front panel (54).

Front panel (54) is transparent in the present example, though this is merely optional. Door (50) is configured to travel vertically relative to lower enclosure (20) between a closed position (FIG. 1) and an open position (FIGS. 2-3). Various suitable features that may be used to provide such mobility for door (50) will be apparent to those of ordinary skill in the art in view of the teachings herein. It should also be understood that door (50) may include a counterbalance system or other system to assist in raising and lowering of door (50), a locking system to assist in securing the vertical position of door (50), and/or a sensing system to provide sensing of the vertical position of door (50). In some versions, a counterbalance system is used to assist in raising and lowering of door (50); and to assist in maintaining the vertical position of door (50) when an operator releases door (50) at a selected location along the range of vertical travel of door (50). Various suitable forms that such door counterbalance systems, door locking systems, and door sensing systems may take will be apparent to those of ordinary skill in the art in view of the teachings herein. Of course, these systems are merely optional. Likewise, door (50) is merely optional and may be completely omitted in some versions.

[0023] Lower enclosure (20) defines an interior (60) that includes various components of robotic system (10), such that these components of robotic system (10) are at least partially contained within lower enclosure (20). These interior (60) components include a first moving assembly (70), a second moving assembly (72), and a set of labware positioners (74). By way of example only, each labware positioner (74) may be used to support labware, such as tip boxes/racks, microplates, reservoirs, etc. Various suitable kids of equipment that may be supported on each labware positioner (74) will be apparent to those of ordinary skill in the art in view of the teachings herein. It should also be understood that any suitable number of labware positioners (74) may be positioned in interior (60) in any suitable arrangement.

[0024] In the present example, each moving assembly (70, 72) is configured to move within interior (60) based on commands from a controller (100) as described in greater detail below. In particular, each moving assembly (70, 72) is configured to move in at least the x-direction and the z-direction, as indicated by the x-axis and z-axis shown in FIG. 1. In some versions, a portion of each moving assembly (70, 72) is further configured to move in the y-direction, as also indicated by the y-axis shown in FIG. 1. In addition, or in the alternative, each moving assembly (70, 72) may be configured to removably receive a selected interchangeable head that is operable to perform one or more liquid handling operations (e.g., transferring liquid via pipettes, etc.) within interior (60). In addition, or in the alternative, each moving assembly (70, 72) may include one or more gripping features that are operable to selectively grasp and release one or more other components. Various other suitable features and functionalities that may be incorporated into each moving assembly (70, 72) will be apparent to those of ordinary skill in the art in view of the teachings herein. It should also be understood that some variations may include just one moving assembly (70 or 72) or more than two moving assemblies (70, 72).

[0025] II. Exemplary Light Curtain System

[0026] As noted above, some robotic machines may include a light curtain sensing system like the light curtain sensing system disclosed in U.S. Pat. No. 6,166,371, the disclosure of which is incorporated by reference herein. If robotic system (10) were to include such a light curtain sensing system, such a light curtain sensing system would be embedded within a threshold (34) of lower enclosure (20), which spans between front columns (22, 24). It should be understood that a vertical plane extending above threshold (34) provides an entry space for interior (60). As described in U.S. Pat. No. 6,166,371, such a light curtain sensing system may include an alternating linear array of light sources and light sensors. The light sources are configured to project light upwardly to create a light curtain; while the light sensors are configured to detect light reflected back by objects (e.g., a human finger, etc.) that enter the light curtain.

[0027] The configuration of robotic system (10) of the present example may provide certain regions that present blind spots for a light curtain sensing system like the system described in U.S. Pat. No. 6,166,371. In particular, blind spots may exist in regions near the upper ends of front columns (22, 24), particularly those regions under the underside of door (50) when door (50) is in the open position. The upper portions of front columns (22, 24) may create these blind spots by restricting the reflection of light by objects (e.g., human fingers) that are passed through the region of the light curtain adjacent to the upper portions of front columns (22, 24). Accordingly, robotic system (10) of the present example includes an enhanced light curtain sensing system that eliminates the blind spots that would be otherwise created due to the presence of columns (22, 24). This light curtain sensing system is described in greater detail below with reference to FIGS. 4-10. [0028] As best seen in FIG. 4, a light curtain assembly (80) is positioned along threshold

(34) of lower enclosure (20). In the present example, light curtain assembly (80) extends along the full length of threshold (34), such that light curtain assembly (80) spans from front column (22) to front column (24). FIGS. 5-6 show light curtain assembly (80) in greater detail. As shown, light curtain assembly (80) comprises a housing (82), a collimator strip (84), an array of light sources (90), and a plurality of light sensors (92). In some versions, a lens (not shown) is positioned over light curtain assembly (80). Such a lens may also extend along the full length of threshold (34), such that the lens spans from front column (22) to front column (24). Alternatively, each light source (90), each light sensor (92), or each light source (90) and light sensor (92) pair may have its own dedicated lens. In some versions, the lens comprises a flat piece transparent glass or plastic. In some other versions, the lens is configured to provide a filter of light transmitted to and from light curtain assembly (80). By way of example only, the lens may be configured to only allow infrared light to pass through the lens. By way of further example only, the lens may comprise a red tinted strip of acrylic that is infrared transmissive. Various suitable materials and configurations that may be used for a lens in association with light curtain assembly (80) will be apparent to those of ordinary skill in the art in view of the teachings herein.

[0029] Collimator strip (84) is configured and positioned as a cap over housing (82), light sources (90), and light sensors (92). Collimator strip (84) of the present example comprises a plurality of light source apertures (86) and a plurality of light sensor apertures (88). Each light source aperture (86) is positioned over an associated light source (90); while each light sensor aperture (88) is positioned over an associated light sensor (92). As best seen in FIG. 6, each light source aperture (86) has a circular shape; while each light sensor aperture (88) has a rectangular shape that extends along a path that is parallel to the length of collimator strip (84). By way of example only, the longitudinally extending edge of each light sensor aperture (88) may have a length that is less than or equal to approximately 0.30 inches, while the transversely extending edge of each aperture (88) may have a length that is less than or equal to approximately 0.07 inches or 0.05 inches. Alternatively, any other suitable dimensions or dimensional relationships may be used. In some variations, apertures (86) are shaped differently (e.g., with a square shape) and/or apertures (88) are shaped differently (e.g., with an elliptical shape).

[0030] It should be understood that apertures (86) and apertures (88) of the present example may be configured to provide collimation for light emitted from light curtain assembly (80) and light received through light curtain assembly (80), respectively. With respect to apertures (88) in particular, apertures (88) may limit the field of view of light sensors (92) to the vertical plane above threshold (34) and light curtain assembly (80). The collimation effect provided by light sensor apertures (88) may thereby reduce the likelihood that light sensors (92) receive light reflected from objects that are outside the plane extending vertically above threshold (34) light curtain assembly (80). In other words, collimation effect provided by light sensor apertures (88) may reduce "false positives," i.e., the occurrence of detections of objects outside the vertical plane over threshold (34).

[0031] It should be understood that the light emitted by light sources (90) is emitted upwardly, toward the underside of door (50). Light sources (90) thus generate the curtain of light along the vertical plane extending vertically above light curtain assembly (80). In the present example, light sources (90) comprise LEDs that are configured to emit infrared light. In addition, light sensors (92) are configured to detect infrared light in the present example. In some other versions, light sources (90) are configured to emit light at other frequencies; and light sensors (92) are configured to detect light at other frequencies. Various suitable kinds of components that may be used to provide light sources (90) and light sensors (92) will be apparent to those of ordinary skill in the art in view of the teachings herein.

[0032] As shown in FIG. 7, front column (22) includes a vertically extending array of light sources (94). While the following discussion relates only to light sources (94) on front column (22), it should be understood that front column (24) may include a complementary set of light sources that are configured and operable just like light sources (94) described below.

In the present example, the array of light sources (94) is only positioned near the upper end of front column (22), such that light sources (94) are not positioned along the lower portion of front column (22). In some other versions, light sources (94) are also positioned along the lower portion of front column (22). Light sources (94) are configured to emit light toward the vertical plane extending above threshold (34). Thus, light sources (94) emit light along the same plane along which light sources (90) emit light. Nevertheless, light sources (94) emit light along a path that is orthogonal to the path along which light sources (90) emit light. In the present example, light sources (94) comprise LEDs that are configured to emit infrared light. In some versions, a collimator strip is positioned over light sources (94). Such a collimator strip may include apertures that are similar to apertures (86); or any other suitable kinds of openings.

[0034] In the present example, no light sensors are positioned along front column (22) adjacent to light sources (94). In some other versions, though, light sensors are positioned along front column (22) adjacent to light sources (94). Such light sensors may form an alternating array with light sources (94), similar to the alternating array formed by light sources (90) and light sensors (92). It should be understood that, even in the present example where no light sensors are positioned along front column (22) adjacent to light sources (94), the light emitted by light sources (94) may be reflected toward light sensors (92) when an object (e.g., an operator's finger) passes through the light curtain extending along the vertical plane above threshold (34). Moreover, the additional light provided by light sources (94) may effectively eliminate the blind spot that might otherwise exist for light sensors (92) in the absence of light sources (94). In other words, light sources (94) may provide enhanced sensitivity of the regions of the light curtain adjacent to the upper portions of front columns (22, 24) (i.e., the regions of the light curtain adjacent to light sources (94)).

[0035] As noted above, door (50) of the present example comprises a frame (52) and a front panel (54). As shown in FIGS. 8-9, door (50) further includes a lower panel (56) that is obliquely oriented relative to a horizontal plane. In the present example, lower panel (56) defines an angle of approximately 45° with a horizontal plane (HP), though it should be understood that lower panel (56) may alternatively define any other suitable oblique angle with the horizontal plane (HP). In addition, lower panel (56) is black in the present example. It should be understood that the black color of lower panel (56), as well as the oblique orientation of lower panel (56), may substantially prevent the bottom of door (50) from reflecting light that is emitted from light sources (90) back to light sensors (92). For instance, the black color may absorb a substantial portion of the light from light sources (90) that reaches lower panel (56); while the obliquely angled orientation may deflect any of the light from light sources (90) away from light sensors (92). It should also be understood that a color other than black may be used for lower panel (56).

[0036] FIG. 10 shows how various components described above are coupled with a controller (100) in the present example. It should be understood that controller (100) may be positioned at any suitable location (or combination of locations) in robotic system (10). Various suitable hardware components that may be used to form controller (100) will be apparent to those of ordinary skill in the art in view of the teachings herein. As shown, controller (100) is in communication with light sources (90, 94), light sensors (92), and moving assemblies (70, 72). In some versions, as will be described in greater detail below, controller (100) is further in communication with a user feedback feature (102).

[0037] Controller (100) is operable to selectively activate light sources (90, 94) in response to various conditions. By way of example only, controller (100) may automatically activate light sources (90, 94) as soon as robotic system (10) is turned on. By way of further example only, controller (100) may automatically activate light sources (90, 94) when door (50) reaches a fully opened (or partially opened) position. In such versions, one or more sensors may be configured to sense the position of door (50) and thereby communicate door (50) position data to controller (100). As yet another merely illustrative example, controller (100) may automatically activate light sources (90, 94) when robotic system (10) has been activated to perform an operation where at least one moving assembly (70, 72) is placed in motion. Various other suitable conditions (and combinations of conditions) that may be used to trigger activation of light sources (90, 94) by controller (100) will be apparent to those of ordinary skill in the art in view of the teachings herein. It should also be understood that controller (100) may activate light sensors (92) based on the same condition (or combination of conditions) that is/are used to trigger activation of light sources (90, 94). [0038] Controller (100) is further operable to activate moving assemblies (70, 72) in response to various conditions. By way of example only, controller (100) may be in further communication with a storage device (not shown) that is configured to store various control algorithms, such that controller (100) is operable to activate moving assemblies (70, 72) to perform routines (e.g., fluid handling routines) by executing one or more control algorithms selected from the storage device. Moreover, controller (100) may be operable to create or alter control algorithms stored on the storage device.

[0039] When controller (100) receives data from one or more light sensors (92) indicating that light from one or more light sources (92, 94) is being reflected by an object (e.g., an operator's finger) passing through the light curtain, such that the object is breaking the vertical plane extending above threshold (34), controller (100) may trigger one or more responses. For instance, if one or more of moving assemblies (70, 72) are in the middle of a routine where one or more of moving assemblies (70, 72) is in motion (or will soon be in motion), controller (100) may halt the routine in response to the sensed presence of an object breaking the vertical plane extending above threshold (34). Thus, controller (100) may halt further movement of all moving assemblies (70, 72) when an object is detected within the light curtain, slow down the motion of moving assemblies (70, 72), or halt further movement of some moving assemblies (70, 72) while allowing others to continue the routine. In some versions, controller (100) may automatically continue the routine of moving assemblies (70, 72) as soon as light sensors (92) sense that the object has been removed from the vertical plane extending above threshold (34). In some other versions, controller (100) may require the operator to provide further user input (e.g., press a button) in order to start the routine of moving assemblies (70, 72) back up after light sensors (92) sense that the object has been removed from the vertical plane extending above threshold (34).

[0040] As noted above, in some versions, controller (100) is in communication with a user feedback feature (102). In such versions, controller (100) may be configured to activate user feedback feature (102) when light sensors (92) detect the presence of an object in the vertical plane extending above threshold (34). This activation of user feedback feature (102) may be performed simultaneously with the halting of the routine of moving assemblies (70, 72). By way of example only, user feedback feature (102) may comprise an audible feedback feature and/or a visual feedback feature. In versions where user feedback feature (102) comprises an audible component, the audible component may comprise an alert sound (e.g., buzzer, bell, beeping, etc.) and/or a vocal sound (e.g., a prerecorded vocal warning, etc.). In versions where user feedback feature (102) comprises a visual component, the visual component may comprise a light (e.g., a light that flashes or changes color), a textual message (e.g., on a display screen associated with robotic system (10)), and/or a graphical message (e.g., on a display screen associated with robotic system (10)). Various suitable forms that user feedback feature (102) may take, as well as various forms of alerts that may be provided by user feedback feature (102), will be apparent to those of ordinary skill in the art in view of the teachings herein.

[0041] III. Exemplary Combinations

[0042] The following examples relate to various non-exhaustive ways in which the teachings herein may be combined or applied. It should be understood that the following examples are not intended to restrict the coverage of any claims that may be presented at any time in this application or in subsequent filings of this application. No disclaimer is intended. The following examples are being provided for nothing more than merely illustrative purposes. It is contemplated that the various teachings herein may be arranged and applied in numerous other ways. It is also contemplated that some variations may omit certain features referred to in the below examples. Therefore, none of the aspects or features referred to below should be deemed critical unless otherwise explicitly indicated as such at a later date by the inventors or by a successor in interest to the inventors. If any claims are presented in this application or in subsequent filings related to this application that include additional features beyond those referred to below, those additional features shall not be presumed to have been added for any reason relating to patentability.

[0043] Example 1

[0044] A light curtain system for an automated apparatus accessible through an entry space, comprising: (a) a bottom border of the entry space having a first light detection device and a light emission device; (b) a first side border of the entry space having a lower end and an upper end, wherein the lower end of the first side border abuts the bottom border, wherein the first side border includes a second light emission device arranged closer to the upper end of the first side border; and (c) a controller coupled to the light detection device; wherein the light detection device is configured to send a signal to the controller upon detecting light reflected by an object impinged by one of the first light emission device and the second light emission device.

[0045] Example 2

[0046] The light curtain system of Example 1 further comprising a second side border of the entry space having a lower end and an upper end, wherein the lower end of the second side border abuts the bottom border, wherein the second side border includes a third light emission device arranged closer to the upper end of the second side border.

[0047] Example 3

[0048] The light curtain system of Example 2 wherein the first side border and second side border are each perpendicular to the bottom border.

[0049] Example 4

[0050] The light curtain system of any one or more of Examples 2 through 3 wherein the first side border and second side border are parallel to each other.

[0051] Example 5

[0052] The light curtain system of any one or more of Examples 2 through 4 further comprising a door positioned between the first side border and the second side border.

[0053] Example 6

[0054] The light curtain system of Example 5 wherein the door is configured to travel vertically between a closed position and an open position, wherein the closed position blocks the entry space.

[0055] Example 7 [0056] The light curtain system of any one or more of Examples 5 through 6 wherein the door includes a lower panel obliquely oriented relative to a horizontal plane.

[0057] Example 8

[0058] The light curtain system of Example 7 wherein the lower panel defines an angle of approximately 45° with the horizontal plane.

[0059] Example 9

[0060] The light curtain system of any one or more of Examples 7 through 8 wherein the lower panel includes a light- absorbing material.

[0061] Example 10

[0062] The light curtain of any one or more of Examples 1 through 9 wherein the controller is configured to interrupt movement of the automated apparatus in response to receiving the signal from the light detection device.

[0063] Example 11

[0064] The light curtain of any one or more of Examples 1 through 10 wherein the controller is configured to trigger an alarm in response to receiving the signal from the light detection device.

[0065] Example 12

[0066] The light curtain of Example 11 wherein the alarm comprises an audible alarm.

[0067] Example 13

[0068] The light curtain of any one or more of Examples 11 through 12 wherein the alarm comprises a visual alarm.

[0069] Example 14 [0070] The light curtain system of any one or more of Examples 1 through 13 wherein the first side border is perpendicular to the bottom border.

[0071] Example 15

[0072] A light curtain system having a first boundary and a second boundary, comprising:

(a) an emission device arranged on the first boundary, wherein the emission device is configured to emit light; (b) a detection device arranged on the second boundary, wherein the detection device is configured to detect light; and (c) a controller coupled to the detection device and an automated apparatus, wherein the controller is configured to interrupt movement of the automated apparatus in response to the detection device detecting light reflected from an object.

[0073] Example 16

[0074] The light curtain system of Example 15 further comprising a second emission device arranged on the second boundary, wherein the second emission device is configured to emit light.

[0075] Example 17

[0076] The light curtain system of any one or more of Examples 15 through 16 further comprising a third emission device arranged on a third boundary of the light curtain system that opposes the first boundary, wherein the third emission device is configured to emit light.

[0077] Example 18

[0078] The light curtain system of any one or more of Examples 15 through 17 wherein the controller is configured to interrupt movement of the automated apparatus by stopping the movement of the automated apparatus.

[0079] Example 19 [0080] The light curtain system of any one or more of Examples 15 through 18 wherein the controller is configured to interrupt movement of the automated apparatus by decreasing the velocity of the automated apparatus.

[0081] Example 20

[0082] A light curtain assembly comprising: (a) a detection device having a field of view; and (b) a cap arranged over the detection device, wherein the cap includes an aperture; wherein the aperture is a field stop that limits the field of view of the detection device.

[0083] Example 21

[0084] The light curtain assembly of Example 20 further comprising a light emission device.

[0085] Example 22

[0086] The light curtain assembly of Example 21 wherein the cap is arranged over the detection device and the light emission device, and wherein the cap includes a second aperture arranged over the light emission device.

[0087] Example 23

[0088] The light curtain assembly of any one or more of Examples 20 through 22 wherein the aperture is longitudinal in the direction of the light curtain board.

[0089] Example 24

[0090] The light curtain assembly of any one or more of Examples 20 through 23 wherein the aperture is a rectangle with its longest edge in the direction of the light curtain board.

[0091] Example 25

[0092] The light curtain assembly of any one or more of Examples 20 through 24 wherein the aperture is configured to limit the field of view of the detection device in a plane perpendicular to the light curtain board. [0093] IV. Miscellaneous

[0094] It should be appreciated that any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.

[0095] Having shown and described various embodiments of the present invention, further adaptations of the methods and systems described herein may be accomplished by appropriate modifications by one of ordinary skill in the art without departing from the scope of the present invention. Several of such potential modifications have been mentioned, and others will be apparent to those skilled in the art. For instance, the examples, embodiments, geometries, materials, dimensions, ratios, steps, and the like discussed above are illustrative and are not required. Accordingly, the scope of the present invention should be considered in terms of the following claims and is understood not to be limited to the details of structure and operation shown and described in the specification and drawings.