Patent Publication Number: US-11022483-B2

Title: Light detection system and method of using same

Description:
BACKGROUND 
     Sampling programs are used to monitor critical raw materials, in-process materials, finished goods, and processing environments in the food and beverage industry. Similar sampling programs are also used in healthcare settings to monitor the effectiveness of decontaminating environmental surfaces in a patient environment as well as instruments and devices used in screening and therapeutic procedures. Routine sampling and testing can allow quality assurance personnel to detect undesirable materials, such as microorganisms, at a very early stage and take steps to prevent subsequent contamination of equipment and/or products. A variety of tests can be performed to detect these undesirable materials. Examples of such tests include chemical residue tests (e.g., Adenosine triphosphate (ATP) bioluminescence tests and protein colorimetric tests), culture methods, genetic tests (e.g., PCR), immunodiagnostic tests, and bioluminescent tests. 
     Sample-collection devices or apparatuses are typically used to collect surface samples for environmental tests. Commercially-available sample-collection devices include absorbent devices such as sponges, swabs, and the like. In addition, certain sample-collection devices are capable of collecting a predetermined volume of a liquid sample. 
     Because of its use as energy “currency” in all metabolizing systems, ATP can indicate the presence of organic or bioorganic residues in a sample. The presence of ATP can be measured using a bioluminescent enzymatic assay. For example, a luciferin/luciferase enzyme assay system uses ATP to generate light. This light output can be detected and quantified in a light detection device, e.g., a luminometer. The presence of ATP in a sample may be a direct indicator of the presence of a microorganism (i.e., the ATP is derived from microorganisms in a sample containing no other sources of ATP), or the ATP may be an indirect indicator of the presence of a microorganism (i.e., the ATP is derived from vegetative or animal matter and indicates that nutrients that support the growth of microorganisms may be present in the sample). In addition, the presence or absence of ATP in a sample is used routinely to assess the efficacy of cleaning processes, e.g., in food, beverage, healthcare (e.g., environmental surfaces, surgical instruments, endoscopes, and other medical devices), water, and sanitation industries. 
     For example, ATP measurement systems have been utilized as monitoring tools in the food industry for over 15 years to audit the efficacy of sanitation processes. Such systems can detect very small amounts of ATP (e.g., 1 femtomole) on a variety of surfaces commonly found in food processing operations that need to be cleaned and disinfected. Detecting the presence of ATP on surfaces that are supposed to be sanitized can indicate a failure of the cleaning and disinfection process. 
     More recently, ATP monitoring tools have been adopted for a similar purpose in clinical applications to monitor the cleanliness of a patient&#39;s environment. There is now compelling clinical evidence that contaminated surfaces in a hospital make an important contribution to the epidemic and endemic transmission, e.g., of  C. difficile , VRE, MRSA,  A. baumannii , and  P. aeruginosa , and to the endemic transmission of norovirus. Effective infection prevention programs include systematic monitoring of the environment&#39;s cleanliness. ATP monitoring, for example, can provide a quantitative measurement system that can be used to support such a program. 
     SUMMARY 
     In general, the present disclosure provides various embodiments of a light detection device and a method of using such device. In one or more embodiments, the light detection device can include a housing and a support member connected to the housing. In one or more embodiments, the support member can be adapted to be selectively moved between a closed position and an open position. In one or more embodiments, the support member can further be adapted to maintain the light detection device in an upright position when a bottom surface of the housing and the support member are in contact with a working surface and the support member is in the open position. In one or more embodiments, the housing axis can form an angle with a vertical axis of at least 0 degrees and no greater than 45 degrees when the bottom surface and the support member are in contact with the working surface and the support member is in the open position. 
     In one aspect, the present disclosure provides a light detection device that includes a housing including a top surface and a bottom surface, where the housing extends along a housing axis between the top surface and the bottom surface. The device further includes a support member connected to the housing and adapted to be selectively moved from a closed position to an open position, where the support member is further adapted to maintain the light detection device in an upright position when the bottom surface and the support member are in contact with a working surface and the support member is in the open position. The housing axis forms an angle with a vertical axis of at least 0 degrees and no greater than 45 degrees when the bottom surface and the support member are in contact with the working surface and the support member is in the open position. 
     In another aspect, the present disclosure provides a method that includes engaging a support member of a light detection device that is attached to a housing of the light detection device to move the support member from a closed position to an open position, wherein the housing extends along a housing axis between a top surface and a bottom surface of the housing. The method further includes placing the light detection device on a working surface, where the support member is adapted to maintain the light detection device in an upright position when the bottom surface of the housing and the support member are in contact with the working surface and the support member is in the open position. The housing axis forms an angle with a vertical axis of at least 0 degrees and no greater than 45 degrees when the bottom surface and the support member are in contact with the working surface and the support member is in the open position. 
     In another aspect, the present disclosure provides a light detection device that includes a housing having a top surface and a bottom surface, where the housing extends along a housing axis between the top surface and the bottom surface. The device also includes a detector disposed within the housing and adapted to detect light emitted by a sample disposed within the housing, and a tilt detection component that is adapted to determine a tilt angle of the light detection device. The tilt angle is an angle formed between the housing axis and a vertical axis. 
     All headings provided herein are for the convenience of the reader and should not be used to limit the meaning of any text that follows the heading, unless so specified. 
     The term “comprises” and variations thereof do not have a limiting meaning where these terms appear in the description and claims. Such terms will be understood to imply the inclusion of a stated step or element or group of steps or elements but not the exclusion of any other step or element or group of steps or elements. 
     The words “preferred” and “preferably” refer to embodiments of the disclosure that may afford certain benefits, under certain circumstances; however, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the disclosure. 
     In this application, terms such as “a,” “an,” and “the” are not intended to refer to only a singular entity but include the general class of which a specific example may be used for illustration. The terms “a,” “an,” and “the” are used interchangeably with the term “at least one.” 
     The phrases “at least one of” and “comprises at least one of” followed by a list refers to any one of the items in the list and any combination of two or more items in the list. 
     As used herein, the term “or” is generally employed in its usual sense including “and/or” unless the content clearly dictates otherwise. The use of the term “and/or” in certain portions of this disclosure is not intended to mean that the use of “or” in other portions cannot mean “and/or.” 
     The term “and/or” means one or all of the listed elements or a combination of any two or more of the listed elements. 
     As used herein in connection with a measured quantity, the term “about” refers to that variation in the measured quantity as would be expected by the skilled artisan making the measurement and exercising a level of care commensurate with the objective of the measurement and the precision of the measuring equipment used. Herein, “up to” a number (e.g., up to 50) includes the number (e.g., 50). 
     Also herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range as well as the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.). 
     These and other aspects of the present disclosure will be apparent from the detailed description below. In no event, however, should the above summaries be construed as limitations on the claimed subject matter, which subject matter is defined solely by the attached claims, as may be amended during prosecution. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Throughout the specification, reference is made to the appended drawings, where like reference numerals designate like elements, and wherein: 
         FIG. 1  is a schematic front perspective view of one embodiment of a light detection device including a door that is disposed in a closed position. 
         FIG. 2  is a schematic rear perspective view of the light detection device of  FIG. 1  with the door of the device disposed in the closed position. 
         FIG. 3  is a schematic right-side view of the light detection device of  FIG. 1  with the door of the device disposed in the closed position. 
         FIG. 4  is a top plan view of the light detection device of  FIG. 1  with the door of the device disposed in the closed position. 
         FIG. 5  is a schematic front perspective view of the light detection device of  FIG. 1  when the door of the device is disposed in an open position. 
         FIG. 6  is a schematic rear perspective view of the light detection device of  FIG. 1  with the door of the device disposed in the open position. 
         FIG. 7  is a schematic exploded view of a portion of the light detection device of  FIG. 1 . 
         FIG. 8  is a schematic front view of the light detection device of  FIG. 1  grasped by a hand of a user and the door of the device disposed in the closed position. 
         FIG. 9  is a schematic left-side view of the light detection device of  FIG. 1  grasped by the hand of the user and the door of the device disposed in the open position. 
         FIG. 10  is a schematic rear perspective view of another embodiment of a light detection device including a support member that is disposed in an open position. 
         FIG. 11  is a schematic left-side view of the light detection device of  FIG. 10  with the support member disposed in a closed position. 
         FIG. 12  is a schematic left-side view of the light detection device of  FIG. 10  disposed on a working surface and the support member disposed in the open position. 
         FIG. 13  is a schematic bottom perspective view of a portion of the light detection device of  FIG. 10  with the support member disposed in the closed position. 
         FIG. 14  is a schematic bottom perspective view of a portion of the light detection device of  FIG. 10  with the support member disposed in the open position. 
         FIG. 15  is a schematic left-side view of another embodiment of a light detection device including a support member disposed in a closed position. 
         FIG. 16  is a schematic rear perspective view of the light detection device of  FIG. 15  with the support member disposed in the closed position. 
         FIG. 17  is a schematic left-side view of the light detection device of  FIG. 15  with the support member disposed in an open position. 
         FIG. 18  is a graph of relative light units (RLUs) versus time as related to tilt angle for several supply apparatuses disposed at various tilt angles. 
     
    
    
     DETAILED DESCRIPTION 
     In general, the present disclosure provides various embodiments of a light detection device and a method of using such device. In one or more embodiments, the light detection device can include a housing and a support member connected to the housing. In one or more embodiments, the support member can be adapted to be selectively moved between a closed position and an open position. In one or more embodiments, the support member can further be adapted to maintain the light detection device in an upright position when a bottom surface of the housing and the support member are in contact with a working surface and the support member is in the open position. In one or more embodiments, the housing axis can form an angle with a vertical axis of at least 0 degrees and no greater than 45 degrees when the bottom surface and the support member are in contact with the working surface and the support member is in the open position. 
     The light detection devices described herein can include any suitable device, e.g., luminometers, photometers (UV/visible), turbidimeters, colorimeters, fluorometers (e.g., portable devices that use light detection for environmental surface and water sampling, including both biological (microbial) testing and chemical content testing), etc. In one or more embodiments, a light detection device can include a light source (e.g., one or more light emitting diodes), a sample chamber, a light detector (e.g., a photomultiplier tube (PMT), a photodiode, etc.), and in some embodiments an optical system (including, e.g., one or more reflectors, filters, or lenses) to direct the light. In one or more embodiments, a test sample can emit light that is detected by a detector of the light detection device. Devices that detect light from a sample or detect the interaction of light with a sample can include one or more elements that block ambient light from interacting with the detector of the device, e.g., doors, gaskets, opaque housings, etc. 
     The light detection device can be utilized in any suitable application. For example, in one or more embodiments, the light detection device can be utilized to detect and measure light emitted by a sample disposed within the device. The sample can include any suitable sample, e.g., a bioluminescent sample. In one or more embodiments, the light detection device can detect the presence of ATP in a bioluminescent sample by analyzing light emitted by the sample that is produced by a luciferin-luciferase enzymatic reaction. 
     The accuracy and repeatability of currently available ATP detection systems can vary significantly. Such variability can be caused by difficulties in acquiring samples in a repeatable manner. Further, systems that employ a luciferin-luciferase detection chemistry can vary because of the lack of repeatability of how the reagent composition is formulated and the form factor employed to provide the reagents in an assay. In addition, the optical characteristics of the detection system can affect accuracy and repeatability. For example, some detection systems utilize a photomultiplier tube as the detector whereas other systems employ photodiodes. These detection systems can include a port that is connected to a detector disposed within a housing of the system. A sample can be disposed within the housing through the port. These ports, however, can allow ambient light to be transmitted into the detector, which can hinder accurate readings and potentially damage the detector. Some systems may include a door or cap that covers the port to prevent ambient light from being transmitted into the detector. These systems, however, may be awkward to operate as they may require one hand to grasp the system and the other to open and close the door that covers the port. 
     Further, a user may desire to place a light detection device on a working surface while the device is analyzing a sample. Some light detection devices, however, may provide more accurate readings when the device is disposed at a desired tilt angle. As used herein, the term “tilt angle” means an angle formed between a housing axis of a light detection device and a vertical axis. As used herein, the term “vertical axis” refers to an axis that is aligned with the Earth&#39;s gravitational field. In one or more embodiments, a desired tilt angle may be greater than 0°. In such embodiments, the light detection device can include one or more support members connected to a housing of the device that can support the device at the desired tilt angle when the device is disposed on the working surface. 
       FIGS. 1-9  are various views of one embodiment of a light detection device  10 . The light detection device  10  can include any suitable light detection device, e.g., a luminometer. In one or more embodiments, the device  10  can be part of a light detection system that can also include a sampling apparatus (not shown) that can be disposed within the device  10  and contain a sample. Any suitable sampling apparatus can be utilized, e.g., the sampling apparatuses described in PCT Patent Publication No. WO 2014/007846 and U.S. Patent Publication No. 2012/0329081. 
     The device  10  can include a housing  12  that can take any suitable shape or combination of shapes. In one or more embodiments, the housing  12  can take an ergonomic shape or combination of shapes that allows a user to grasp the housing and operate the device  10  with a single hand. Further, the housing  12  can be a single, unitary housing or can include two or more pieces, sections, or portions that are attached together using any suitable technique or combination of techniques. The housing  12  can extend along a housing axis  4  between a top surface  14  and a bottom surface  16 . The housing  12  can also include an optional handle portion  18  disposed between the top surface  14  and the bottom surface  16 . The handle portion  18  can include any suitable shape or combination of shapes. The housing  12  can also include a front surface  13  that extends between the top surface  14  and the bottom surface  16 , and a back surface  15  that also extends between the top surface and the bottom surface. 
     The housing  12  can also include a port  20  disposed in the top surface  14  of the housing ( FIGS. 5-7 and 9 ). Although illustrated as being disposed in the top surface  14 , the port  20  can be disposed in any suitable surface of the housing  12 , e.g., in the bottom surface  16 , front surface  13 , or back surface  15  of the housing. The port  20  can be adapted to allow a user to dispose a sample within the housing  12  such that light emitted by or interacting with the sample can be detected by a detector (not shown) disposed within the housing. The detector can be any suitable detector, e.g., the detectors described in cofiled U.S. Provisional Patent Application No. 62/132,774, filed Mar. 13, 2015. In one or more embodiments, the port  20  can be connected to the detector such that a sample can be disposed within the housing through the port and positioned within the housing such that the detector can measure one or more characteristics of the sample. For example, if the sample includes a photoluminescent sample, then the detector can be utilized to measure, e.g., an intensity of light emitted by the photoluminescent sample. 
     The port  20  can be adapted to receive a sample. The sample can be disposed within the housing  20  in any suitable manner. For example, in one or more embodiments, the sample can be directly disposed within the housing through the port  20 . In one or more embodiments, the sample can be contained within a sampling apparatus that is adapted to be disposed within the housing by being inserted into the port  20 . The port  20  can take any suitable shape or combination of shapes. In one or more embodiments, the port  20  can be adapted to receive a sampling apparatus. 
     In one or more embodiments, the port  20  can be connected to a receptacle (not shown) that is disposed within the housing  12 . The receptacle can be adapted to receive a sampling apparatus and position the apparatus within the housing such that the detector can measure one or more characteristics of a sample disposed within the sampling apparatus. Any suitable receptacle can be utilized, e.g., one or more of the receptacles described in cofiled U.S. Provisional Patent Application No. 62/132,774, filed Mar. 13, 2015. 
     The light detection device  10  can also include one or more controls  22  that are adapted to provide an interface for the user to perform various functions with the device  12 . Any suitable control or controls  22  can be provided with the device  10 . Further, in one or more embodiments, the controls  22  can be disposed in any suitable location on or in the housing  12 . For example, in the embodiment illustrated in  FIG. 1 , the controls  22  are disposed on or in a front surface  13  of the housing  12  such that a user can grasp the handle portion  18  of the housing  12  and operate the controls with a thumb or finger of the grasping hand. Such positioning of the controls  22  can allow operation of the device  10  with a single hand. The controls  22  can provide an interface for a user and can be electrically coupled to any suitable circuitry disposed within the housing  12  of the device  10 . Such circuitry can include any suitable electronic device or devices, e.g., one or more controllers, processors, storage devices, power converters, analog/digital converters, GPS components, wireless antennas and receivers, etc. The circuitry can be electrically coupled to any suitable power source or sources, e.g., batteries, external power sources, etc. The circuitry can be connected to any suitable external device or power source through, e.g., one or more additional ports  26  disposed on or in the housing in any suitable location. 
     The device  10  can also include a display  24  that is adapted to provide a user with an interface with the circuitry disposed within the housing  12  of the device. The display  24  can be in any suitable location on or in the housing  12 . In the embodiment illustrated in  FIG. 1 , the display  24  is disposed in the front surface  13  of the housing. The display  24  can include any suitable display. In one or more embodiments, the display  24  can be a touch-sensitive display that can provide the user with control of the device and can also display information to the user. Any suitable touch sensitive display  24  can be utilized with device  10 . 
     The light detection device  10  can also include a door  30 . The door  30  can be connected to the housing  12  of the device  10  using any suitable technique or combination of techniques. The door  30  can include any suitable material or combination of materials. In one or more embodiments, the door  30  includes the same material or combination of materials as the housing  12  of the device  10 . Further, the door  30  can take any suitable shape or combination of shapes and have any suitable dimensions. 
     In one or more embodiments, the door  30  can include an actuator portion  32  and a cover portion  34  connected to the actuator portion. In one or more embodiments, the actuator portion  32  can be integral with the cover portion  34 , or the actuator portion and the cover portion can be separate elements that are connected using any suitable technique or combination of techniques. For example, in one or more embodiments, the actuator portion  32  and the cover portion  34  can be connected by a hinge (e.g., hinge  36  of  FIG. 7 ). 
     The door  30  can be adapted such that it can be disposed in a closed position or an open position. For example,  FIGS. 1-4 and 8  are various views of the device  10  when the door  30  is disposed in a closed position  6 . Further, for example,  FIGS. 5-6 and 9  are various views of the device  10  when the door is disposed in an open position  8 . The door  30  can be disposed in the closed position  6  or the open position  8  using any suitable technique or combination of techniques. For example, in one or more embodiments, the actuator portion  32  is adapted to selectively move the door  30  between the closed position  6  and the open position  8 . Further, in one or more embodiments, the cover portion  34  of door  30  is adapted to close the port  20  when the door is in the closed position  6  and open the port when the door is in the open position  8 . When in the open position  8 , the cover portion  34  can allow external access to the port  20 . 
     The door  30  can be connected to the housing  12  of device  10  using any suitable technique or combination of techniques. For example, in one or more embodiments, the door  30  can be attached to the housing  12  by a hinge  36  as shown in  FIG. 7 . The hinge  36  can be any suitable hinge. In the embodiment illustrated in  FIG. 7 , the hinge  36  includes a protuberance  37  that is adapted to be disposed within an opening  11  formed in the housing  12 . The door  30  can include any suitable number of protuberances  37  such that the hinge  36  attaches the door to the housing  12 . In one or more embodiments, the hinge  36  can be attached to the housing  12  by inserting the protuberance  37  into the opening  11  disposed in one or both of two sections  60 ,  62  of the housing  12 . The sections  60 ,  62  of the housing  12  can be secured together by screws  44  that are inserted through openings  45 . The hinge  36  can be disposed in any suitable location on or in the housing  12  and in any suitable orientation relative to the housing axis  4 . 
     Further, in one or more embodiments, a spring  38  can be disposed between the door  30  and the housing  12 . Any suitable spring can be utilized. The spring  38  is adapted to allow the door  30  to pivot between the closed position  6  and the open position  8 . In one or more embodiments, the door  30  can be biased in either the closed position  6  or the open position  8 . In the embodiment illustrated in  FIG. 7 , the spring  38  biases the door  30  in the closed position  6  such that the port  20  is closed to the external environment. By biasing the door  30  in the closed position  6 , the cover portion  34  can protect the port  20  and prevent ambient light or other environmental elements (e.g., moisture) from entering the interior of the housing  12  through the port. When in the closed position  6 , the cover portion  34  can also prevent ambient light from entering a detector disposed within the housing. 
     In one or more embodiments, the actuator portion  32  of the door  30  is adapted to rotate the door about a rotation axis  5  as shown in  FIG. 6 . The rotation axis  5  can be oriented in any suitable relationship to the housing axis  4 . For example, in one or more embodiments, the rotation axis  5  can be substantially orthogonal to the housing axis  4  as shown in  FIG. 6 . As used herein, the phrase “substantially orthogonal” means that the rotation axis  5  is disposed such that an angle of between 85° to 95° is formed with the housing axis  4 . In one or more embodiments, the rotation axis  5  can be aligned with the hinge  36  ( FIG. 7 ). 
     The actuator portion  32  of door  30  is adapted to selectively move the door from the closed position  6  to the open position  8 . Further, the actuator portion  32  can take any suitable shape or combination of shapes. In one or more embodiments, the actuator portion  32  can take a curved shape such that it is adapted to receive a finger of a hand of a user. Further, in one or more embodiments, the actuator portion  32  can include a textured surface  33  such that the user can more easily engage the actuator portion to place the door either in the closed position  6  or the open position  8 . 
     The actuator portion  32  can be disposed in any suitable relationship relative to the housing  12 . In one or more embodiments, the actuator portion  32  can be disposed adjacent the handle portion  18  of the housing  12 . As used herein, the phrase “adjacent the handle portion” means that the actuator portion  32  is disposed closer to the handle portion  18  than to either the top surface  14  or the bottom surface  16  of the housing  12 . The actuator portion  32  can be disposed adjacent the handle portion  18  such that the user can grasp the handle portion and engage the actuator portion with a single hand. In other words, the light detection device  10  can be adapted to allow a user to grasp the handle portion  18  with a hand and, with the same hand, engage the actuator portion  32  to selectively move the door  30  between the closed position  6  and the open position  8 . 
     Connected to the actuator portion  32  is the cover portion  34 . In one or more embodiments, the cover portion  34  is adapted to close the port  20  when the door  30  is in the closed position  6  and open the port when the door is in the open position  8  to allow external access to the port. In one or more embodiments, the cover portion  34  of the door  30  is adapted to minimize the amount of ambient light entering the port  20  when the door is in the closed position  6 . In one or more embodiments, the door  30  is adapted to prevent substantially all ambient light from entering the port  20  when the door is in the closed position  6 . In one or more embodiments, the door  30  is adapted to block a sufficient amount of ambient light from entering the housing  12  such that the ability to detect and measure a light signal associated with the sample is not compromised. 
     The cover portion  34  can be disposed in any suitable relationship relative to the housing  12 . In one or more embodiments, the cover portion  34  is disposed such that it forms a portion of the top surface  14  of the housing  12 . In one or more embodiments, the cover portion  34  can be level or flush with the top surface  14  of the housing  12  when the door  30  is in the closed position  6 . 
     In one or more embodiments, the port  20  can include a ledge  40  that is adapted to engage the cover portion  34  when the door  30  is in the closed position  6 . The ledge  40  can take any suitable shape or combination of shapes. Further, the ledge  40  can be disposed along an entire perimeter of the port  20  or along any suitable portion of the perimeter of the port. The combination of the cover portion  34  and ledge  40  can prevent ambient light from entering the port  20  when the door  30  is in the closed position  6 . 
     In one or more embodiments, the port  20  can also include a gasket (not shown) that is disposed between the cover portion  34  and the ledge  40 . The gasket can extend along any suitable portion of the ledge  40  of the port  20 . In one or more embodiments, the gasket extends along the entire ledge  40 . The gasket, ledge  40 , and the cover portion  34  can combine to prevent ambient light from entering the port  20 . Further, in one or more embodiments, the gasket can also provide a seal between the cover portion  34  and the ledge  40  to prevent external environmental elements from entering the port  20 , e.g., moisture. Further, one or more of the gasket, ledge  40 , and cover portion  34  can prevent a sample disposed within the housing  12  from undesirably leaking out of the housing. 
     In one or more embodiments, the port  20  can also include an overhang (not shown) that covers any space between the top surface  14  and the cover portion  32  when the door  30  is in the closed position  6 . The overhang can take any suitable shape and be located in any suitable location. In one or more embodiments, the overhang can be connected to the top surface  14  and/or the cover portion  34 . 
     The door  30  can also include a first end  35  and a second end  39  ( FIG. 7 ). In one or more embodiments, the actuator portion  32  is adjacent the first end  35  and the cover portion  34  is adjacent the second end  39 . As used herein, the phrase “adjacent the first end” means that the actuator portion  32  is disposed closer to the first end  35  of the door  30  than to the second end  39  of the door. Similarly, the phrase “adjacent the second end” means that the cover portion  34  is disposed closer to the second end  39  of the door than to the first end  35 . 
     As mentioned herein, the rotation axis  5  can be disposed at any suitable location relative to the door  30 . In one or more embodiments, the rotation axis  5  can be disposed between the first end  35  and the second end  39  of the door  30 . In one or more embodiments, the rotation axis  5  is disposed at approximately a midpoint between the first end  35  and the second end  39  of the door  30 . As used herein, the term “approximately” means that the rotation axis  5  is disposed within 1 cm of the midpoint between the first end  35  and the second end  39  of the door  30 . In one or more embodiments, the rotation axis  5  is disposed closer to the first end  35  of the door  30  than to the second end  39 . Further, in one or more embodiments, the rotation axis  5  is disposed closer to the second end  39  of the door  30  than to the first end  35 . 
     In one or more embodiments, the rotation axis  5  is disposed closer to the midpoint between the first and second ends  35 ,  39  of the door  30  than to either the first end or the second end of the door. In one or more embodiments, the rotation axis  5  is disposed about halfway between the midpoint located between the first and second ends  35 ,  39  of the door  30  and the first end. In one or more embodiments, the rotation axis  5  is disposed about halfway between the midpoint located between the first and second ends  35 ,  39  of the door  30  and the second end. 
     In one or more embodiments, the actuator portion  32  can be defined as a portion of the door  30  disposed between the rotation axis  5  and the first end  35 . Further, in one or more embodiments, the cover portion  34  of the door  30  can be defined as a portion of the door disposed between the rotation axis  5  and the second end  39  of the door. The actuator portion  32  can include any suitable portion of door  30 , e.g., no greater than about 90%, no greater than about 80%, no greater than about 70%, no greater than about 60%, no greater than about 50%, etc. In one or more embodiments, the actuator portion  32  can be at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50% of the door  30 . Further, the cover portion  34  of door  30  can include any suitable portion of the door, e.g., no greater than about 90%, no greater than about 80%, no greater than about 70%, no greater than about 60%, no greater than about 50%, etc. In one or more embodiments, the door portion  34  can be at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50% of the door  30 . 
     The light detection device  10  can also include a switch (not shown) that is coupled to the door  30  and adapted to activate circuitry and/or a detector disposed within the housing (not shown) when the door is disposed in the closed position  6 . Any suitable switch or combination of switches can be utilized. Further, in one or more embodiments, the switch can deactivate circuitry and/or a detector disposed within the housing  12  when the door  30  is disposed in the open position  8  to prevent ambient light from damaging the detector. The switch can be disposed in any suitable position relative to the door  30 . In one or more embodiments, the switch can be positioned between the actuator portion  32  and the housing  12 . 
     As mentioned herein, the door  30  can be disposed in any suitable location relative to the housing  12 . In one or more embodiments, the door  30  is disposed such that the actuator portion  32  is adjacent the back surface  15  of the housing. As used herein, the phrase “adjacent the back surface” means that the actuator portion  32  is disposed closer to the back surface  15  of housing  12  than to the front surface  13 . In one or more embodiments, the back surface  15  of the housing  12  can include a recessed portion  17  that is adapted to receive the door  30  as illustrated in  FIG. 7 . In one or more embodiments, the door  30  can sit within the recessed portion  17  of the back surface  15  such that an outer surface of the door is level or flush with the adjacent back surface. 
     In one or more embodiments, the door can be disposed on a side surface of the housing  12  between the front surface  13  and the back surface  15 . Further, in one or more embodiments, the door  30  can be disposed on the front surface  13  of the housing  12  adjacent the display  24  such that a user can engage the actuator portion  32  of the door with the thumb of the grasping hand. In such embodiments, the door  30  can include an opening or openings such that the user can access the controls  22  and view the display  24  through the door. In one or more embodiments, the door  30  can be disposed on the front surface  13  of the housing  12  on either side of the display  24  such that the user can access the controls  22  and view the display  24 . 
     The back surface  15  can also include a finger receiving region  28  adjacent the actuator portion  32  of the door  30  ( FIG. 6 ). As used herein, the phrase “adjacent the actuator portion” means that the finger receiving region  28  of the housing  12  is disposed closer to the actuator portion  32  than to the cover portion  34  of door  30 . The finger receiving region  28  is adapted to receive one or more fingers of a user&#39;s hand when the user grips the handle portion  18  of the light detection device  10 . The finger receiving region  28  is shaped such that a finger of a user can engage the actuator portion  32  of the door  30  and engage the actuator portion to move the cover portion  34  between the closed position  6  and the open position  8 . In one or more embodiments, when the actuator portion  32  is engaged such that the door  30  is moved to the open position  8 , the finger receiving region  28  accommodates a finger of a user to allow the finger to hold the actuator portion against the recessed portion  17  of the back surface  15  of the housing  12 . In one or more embodiments, the finger receiving region  28  takes a shape that is complementary with the shape of the actuator portion  32  when the actuator portion is engaged and the door  30  is in the open position  8  as illustrated in  FIG. 6 . 
     The light detection device  10  can be utilized in any suitable manner to measure one or more characteristics of a sample disposed within the housing  12  of the device. For example,  FIGS. 8-9  illustrate one technique for utilizing the device  10 . As illustrated, a hand  50  of the user is shown in  FIG. 8  grasping the handle portion  18  of the device  10 . The hand  50  can engage the actuator portion  32  of the door  30  to move the door between the closed position  6  ( FIG. 8 ) and the open position  8  ( FIG. 9 ). When in the open position  8 , the cover portion  34  opens the port  20  to allow external access to the port. In one or more embodiments, the user can engage the actuator portion  32  of the door  30  by pressing the actuator portion with a finger or thumb  54  of the hand  50  that is grasping the handle portion  18  of the housing  12 . Engaging the actuator portion  32  can cause the door  30  to rotate about the rotation axis  5  to the open position  8 . In one or more embodiments where the door  30  is biased in the closed position  6 , pressing the actuator portion  32  of the door  30  opens the door, i.e., places the door in the open position  8 . 
     When the door  30  is in the open position  8  as shown in  FIG. 9 , a sample or a sampling apparatus can be disposed within the housing  12  through the port  20 , e.g., into a receptacle disposed within the housing. While the sample is being disposed within the housing  12 , the finger or thumb  54  of the hand  50  of the user can maintain a force on the actuator portion  32  of the door  30  to keep the door in the open position  8 . 
     In one or more embodiments, a latch (not shown) can be attached to the housing  12 . The latch can be adapted to hold the door  30  in the open position  8  such that the user&#39;s finger can be disengaged from the actuator portion without the door returning to the closed position  6 . Any suitable latch can be utilized. In embodiments where a latch is included, the door  30  can be moved from the open position  8  to the closed position  6  by engaging the actuator portion  32  of the door by applying a force to the actuator portion in a direction toward the interior of the housing  12 , thereby releasing the door from the latch. Once the latch is released, the biasing of the door  30  will return the door to the closed position  6  when the user reduces the force applied to the actuator portion  32 . In one or more embodiments, the user can move the door  30  from the open position  8  to the closed position  6  by releasing the actuator portion  32  such that the biasing of the door returns the door to the closed position  6  and the cover portion  34  of the door closes the port  20  of the housing  12 . 
     In one or more embodiments, the device  10  can include a switch that activates circuitry disposed within the housing when the sample is disposed within the housing and the door is in the closed position  6 . The circuitry can be activated by the switch using any suitable technique or combination of techniques. One or more characteristics of the sample can be measured after the door  30  has been moved from the open position  8  to the closed position  6 . Any suitable characteristic or characteristics of the sample can be measured, e.g., intensity of light emitted by the sample. 
     In one or more embodiments, the detection device  10  can also include a tilt detection component (not shown) that can, in one or more embodiments, measure a tilt angle of the detection device  10 . The tilt detection component can provide feedback to a user when the device  10  is positioned within a proper tilt angle and/or when the device is positioned at an improper tilt angle. Such feedback can be provided to the user using any suitable technique or combination of techniques, e.g., the feedback can be provided as a readout on the display  24 , or the device  10  can be adapted to provide haptic feedback to the user. For example, during detection of light emitted by a sample, the user can be warned by an on-screen message on display  24 , or the device  10  can provide haptic feedback, when the instrument is not being held at the correct tilt angle and/or when the instrument is being held at the correct tilt angle. On-screen instructions can be provided to the user to reorient the device  10  such that it is positioned within the correct tilt angle. The tilt detection component can be utilized to indicate to a user any suitable tilt angle or range of tilt angles. In one or more embodiments, a desirable tilt angle can be determined, e.g., by the quantity of a sample disposed within the housing, and by the optical properties and configurations of the detector within the housing. In general, the tilt angle can be selected to provide the most accurate detection of one or more characteristics of a sample disposed within the housing. 
     The tilt detection component can include any suitable circuitry or elements that can determine an orientation of the device  10  relative to the vertical axis. For example, in one or more embodiments, the tilt angle can be measured by a tilt sensor that is sampled by a microprocessor disposed either within the housing  12  of the device  10  or external to the housing  10  and coupled to the tilt sensor either wirelessly or through a wired coupling. Data provided by the tilt sensor can be averaged or normalized to yield a stable approximation of the tilt angle of the device  10  prior to or during analysis of the sample. The tilt detection component can be calibrated to have any suitable accuracy. For example, in one or more embodiments, the tilt detection component can be calibrated such that it provides, e.g., a 20% tilt angle measurement accuracy. 
     A calibrated 3M Clean-Trace™ NG Luminometer (commercially available from 3M Company, St. Paul, Minn.) was used to measure light in relative light units (RLUs) emitted by several bioluminescence samples disposed in several different sampling apparatuses. The Luminometer was fixtured in a holder for stability and repeatability of tilt angles during the test. The following tilt angles were measured: 0 degrees (vertical), 45 degrees (a commonly observed viewing angle used by users to maximize display contrast), and 90 degrees (simulates the Luminometer resting horizontally on a work surface). These three states were cycled through two times and return to vertical. A plurality of RLU readings was automatically acquired in each angle state to average out temporal variation and assay decay. The Luminometer was controlled by a computer running an RLU data logging program with a sample interval of 20 seconds. 
       FIG. 18  is a graph of RLUs versus time that illustrates RLUs relative to various tilt angles that were measured. Tilt angles of 45 degrees typically reduced RLU readings by 10%. Tilt angles of 90 degrees typically reduced RLU readings by 25%. 
     While not wishing to be bound by any particular theory, measuring a sample with an instrument not held at the appropriate angle can yield a measured value difference greater than 20% relative to the real value because the sample being measured can typically be a small volume (less than 1 mL) liquid sample disposed in a cuvette portion of the sampling apparatus, where the sample can have an appreciable meniscus. When the device is held in an improper angle, at least a portion of the sample can be disposed outside of a light cavity of the detection device of the system that directs light to a detector, thereby reducing a volume of the sample that can emit light into the light cavity and, therefore, potentially yielding an erroneous signal. This tilt can, therefore, affect the radiance of the sample being analyzed. 
     In one or more embodiments, the tilt detection component can also be utilized to measure customer usage behaviors and abuse events that can be useful in predicting desired service intervals or provide training and guidance. Further, one or more embodiments of the tilt detection component can provide real-time mathematical normalization of RLU data based on measured tilt angle. This algorithm may be constrained to practical tilt angle limits. For example, measured angles greater than 90 degrees would prompt an immediate warning and suppress a normalization algorithm. In one or more embodiments, providing a user feedback on the tilt angle can allow the user to maintain the same tilt angle across multiple samples, thereby allowing for more consistent readings from sample to sample and from sampling period to sampling period. 
     Any suitable technique or combination of techniques can be utilized to maintain the light detection device  10  in a position having a desired tilt angle. For example, in one or more embodiments, a support member or members can be connected to the housing of the device such that the device can be placed on a working surface at the desired tilt angle. 
     For example,  FIGS. 10-14  are various views of one embodiment of a light detection device  110 . All of the design considerations and possibilities regarding the light detection device  10  of  FIGS. 1-9  apply equally to the light detection device  110  of  FIGS. 10-14 . The light detection device  110  includes a housing  112  that extends along a housing axis  104  between a top surface  114  and a bottom surface  116 . The housing  112  also includes a front surface  113  that extends between the top surface  114  and the bottom surface  116 , and a back surface  115  that also extends between the top surface and the bottom surface. 
     One difference between light detection device  110  and device  10  of  FIGS. 1-9  is that device  110  includes a support member  160 . Support member  160  can be connected to the housing  112  in any suitable location and using any suitable technique or combination of techniques. In one or more embodiments, the support member  160  is integral with the housing  112 . In one or more embodiments, the support member  160  is attached to the housing  112  and can be removed from the housing without damaging either the housing or the support member. 
     In the embodiment illustrated in  FIGS. 10-14 , the support member  160  is connected to the housing  112  adjacent the bottom surface  116 . As used herein, the phrase “adjacent the bottom surface” means that the support member  160  is connected to the housing  112  closer to the bottom surface  116  than to the top surface  114 . The support member  160  can be connected to the housing  112  using any suitable technique or combination of techniques. For example,  FIG. 13  is a schematic perspective view of the bottom surface  116  of the housing  112 . The support member  160  in the illustrated embodiment is attached to the bottom surface  116  via a hinge  170 . The hinge  170  can include any suitable hinge. In one or more embodiments, the hinge  170  can be a living hinge. Further, in one or more embodiments, the hinge  170  can be a ratcheted hinge that includes teeth  171  formed in the bottom surface  116  of the housing  112  that engage one or more notches  173  formed in the hinge. The ratcheted hinge  170  can be adapted to allow adjustment of the positioning of the support member  160 . 
     In one or more embodiments, the support member  160  can be adapted to selectively move from a closed position  106  to an open position  108 . For example, in  FIG. 13 , the support member  160  is in a closed position  106 , i.e., a second major surface  164  (shown in  FIG. 14 ) faces the bottom surface  116  of the housing  112 . In  FIG. 14 , the support member  160  is disposed in the open position  108 , i.e., the second major surface  164  of the support member does not face the bottom surface  116  of the housing  112 . In one or more embodiments, the support member  160  can be fixed in the open position  108  and is not movable to a closed position  106 . 
     The support member  160  can be adapted to maintain the light detection device  110  in an upright position when the bottom surface  116  and the support member are in contact with a working surface  102  and the support member is in the open position  108  as is shown in  FIG. 12 . As used herein, the phrase “upright position” means that the light detection device  10  is disposed such that the top surface  114  is above the bottom surface  116  as viewed from the user&#39;s perspective, and the housing axis  104  forms an angle with a vertical axis that is less than 90°. In one or more embodiments, the housing axis  104  forms any suitable angle with the working surface  102  when the light detection device  110  is in the upright position and in contact with the working surface  102 . At least a portion of the second major surface  164  of the support member  160  is adapted to contact the working surface  102  when in the open position  108  as shown in  FIG. 12 . Further, any suitable angle  101  can be formed between the housing axis  104  and the vertical axis  103 . In one or more embodiments, angle  101  can be 0°, at least 0°, no greater than 90°, no greater than 45°, no greater than 30°, no greater than 15°. 
     In one or more embodiments, the bottom surface  116  can be adapted such that it is generally perpendicular to the housing axis  104 . In such embodiments, the device  110  can rest on the working surface  102  such that the bottom surface  116  is flat with the working surface and the device is in a vertical position, i.e., the housing axis  104  is parallel to the vertical axis  103 . 
     The bottom surface  116  can include a recessed portion  117  that is adapted to receive the support member  160  when the member is in the closed position  106  as is illustrated in  FIG. 13 . In one or more embodiments, the support member  160  is flush with the bottom surface  116  when the member is disposed within the recessed portion  117  and, therefore, in the closed position  106 . In one or more embodiments, the recessed portion  117  of the bottom surface  116  of the housing  112  is adapted to engage the support member  160  in a snap-fit relationship when the support member is in the closed position  106 . The support member  160  can be attached to the bottom surface  160  using any suitable hinge such that the support member can be received by a recessed portion formed in both of the front and back surfaces  113 ,  115 . 
     The bottom surface  116  can also include a second recessed portion  172  that is adapted to house the hinge  170  such that the support member  160  is flush with the bottom surface  116  when in the closed position  106  ( FIG. 13 ). The hinge  170  can be disposed in the second recessed portion  172 . The second recessed portion  172  can also include a ledge  174  that is adapted to engage the support member  160  when the support member is in the open position  108  ( FIG. 14 ). The ledge  174  can prevent the support member  160  from being over rotated such that the first major surface  162  contacts the back surface  115  of the housing  112 . 
     The user can engage the support member  160  by engaging a portion of the member when the member is in the closed position  106 , and moving the member from the closed position to the open position  108  by rotating the member about the hinge  170  until the member engages the ledge  174  of the recessed portion  172 . In embodiments where the hinge  170  is a ratcheted hinge, the user can rotate the support member  160  from the closed positon  106  to the open position  108  to achieve a selected angle between the first major surface  162  of the support member and the housing axis  104 . Once the desired angle has been selected, the user can operate the device  110  while either holding the device in a hand or resting the device on the working surface  102  such that the device rests in an upright position at the selected angle  101  between the housing axis  104  and the vertical axis  103 . If desired, the user can, in one or more embodiments, grasp the device  110  and lift it from the working surface  102  to adjust the angle between the first major surface  162  of the support member  160  and the housing axis  104 , and then place the device on the working surface at a selected second angle between the housing axis  104  and the vertical axis  103 . 
     In one or more embodiments, the support member  160  can be held in the closed position  106  using a tab or other interference feature. The support member  160  can then be released from the closed position  106  and moved to the open position  108  either manually or by using a button or switch to move the tab or interference feature out of the way. In one or more embodiments, the support member  160  can move from the closed position  106  to the open position  108  with the assistance of a spring mechanism. 
     As mentioned herein, the support member  160  can be connected to the housing  112  of the light detection device  110  in any suitable location. For example,  FIGS. 15-17  are various views of another embodiment of a light detection device  210 . All of the design considerations and possibilities regarding the light detection device  10  of  FIGS. 1-9  and the light detection device  110  of  FIGS. 10-14  apply equally to the light detection device  210  of  FIGS. 15-17 . The device  210  includes a housing  212  extending along a housing axis  204  between a top surface  214  and a bottom surface  216 . The device  210  also includes a support member  260  connected to the housing  212  and adapted to be selectively moved between a closed position  206  (as shown in  FIGS. 15-16 ) and an open position  208  (as shown in  FIG. 17 ). The support member  260  is also adapted to maintain the light detection device  210  in an upright position when the bottom surface  216  and the support member  260  are in contact with a working surface  202  and the support member is in the open position  208  ( FIG. 17 ). The housing axis  204  can form any suitable angle  201  with a vertical axis  203  when the bottom surface  216  and the support member  260  are in contact with the working surface  202  and the support member is in the open position  208 . 
     One difference between device  110  of  FIGS. 10-14  and device  210  of  FIGS. 15-17  is that the support member  260  is attached to a back surface  215  of the housing  212  and not the bottom surface  216 . In one or more embodiments, the support member  260  can be in contact with the back surface  215  of the housing when the support member is in the closed position  206  as shown in  FIGS. 15-16 . In the closed position  206 , a first major surface  262  of the support member  260  can face away from the housing  212  and a second major surface  264  can face the housing. The back surface  215  can include a recessed portion (not shown) that is adapted to receive the support member  260  when the support member is in the closed position  206  (see  FIG. 16 ). In one or more embodiments, the support member  260  can be snap-fit into the recessed portion such that the support member remains in the closed position  206  as the user holds the device in various orientations. For example, the support member  260  can be snap-fit within the recessed portion such that the support member remains in the closed position  206  when the device is in a horizontal orientation, i.e., the housing axis  204  is substantially parallel to a horizontal axis. In one or more embodiments, the support member  260  can be flush with the back surface  215  when the support member is in the closed position  206 . 
     The support member  260  can be connected to the housing  212  using any suitable technique or combination of techniques. In one or more embodiments, the support member  260  can be attached to the housing with any suitable hinge. The hinge can also include a ratcheted hinge, e.g., ratcheted hinge  170  of  FIGS. 13-14 . 
     A user can grasp a portion of the support member  260  and move the support member from the closed position  206  to the open position  208  by rotating the support member about the hinge until a desired angle is formed between the first major surface  262  of the support member and the housing axis  204 . The user can place the light detection unit  210  on the working surface  202  such that the support member  260  maintains the device in an upright position when the bottom surface  216  of the device and the support member are in contact with the working surface. Any suitable angle  201  can be formed between the housing axis  204  and the vertical axis  203 . In one or more embodiments, the support member  260  can stabilize the light detection device  210  when the device is resting on the working surface  202 . 
     In one or more embodiments, the support member  260  can be held in the closed position  206  using a tab or other interference feature. The support member  260  can then be released from the closed position  206  to the open position  208  either manually or by using a button or switch to move the tab or interference feature out of the way. In one or more embodiments, the support member  260  can move from the closed position  206  to the open position  208  with the assistance of a spring mechanism. 
     All references and publications cited herein are expressly incorporated herein by reference in their entirety into this disclosure, except to the extent they may directly contradict this disclosure. Illustrative embodiments of this disclosure are discussed and reference has been made to possible variations within the scope of this disclosure. These and other variations and modifications in the disclosure will be apparent to those skilled in the art without departing from the scope of the disclosure, and it should be understood that this disclosure is not limited to the illustrative embodiments set forth herein. Accordingly, the disclosure is to be limited only by the claims provided below.