Abstract:
A method and device for enhancing the power correction of optical measurements in an optical measurement arrangement, the steps including: providing a light source for producing a light beam; splitting the light beam into two beams; directing a first split light beam through an interrogation area and into an optics separation device; directing the light beams from the optics separation device and a second split light beam representing the intensity of the illumination of the main light beam of the light source into cells of a detector array; measuring and assessing the information obtained in the cells; and using this information to calculate the corrected value for the cells receiving the light beams from the optics separation device in order to adjust the power for the intensity of the light beam of the light source and/or to correct the intensity of the light beams from the interrogation area.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present cross-reference application claims priority to Provisional Application No. 61/150,430, entitled “Optical Measurement Arrangement”, filed on Feb. 6, 2009, which is herein incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to an optical measurement arrangement which includes a detector array assembly having a plurality of detector elements. More specifically, the invention relates to an optical measurement arrangement which corrects the power changes occurring in the optical measurement arrangement when performing the optical measurement of a signal which is a result of a light illumination. The optical measurement arrangement of the invention may find particular application in an optical analyzer for analyzing urine samples. 
         [0004]    2. Description of Related Art 
         [0005]    In general, current-day practice for identifying micro-organisms, e.g., bacteria in urine specimens involves a complex, lengthy and expensive process for identifying and specifying micro-organisms in microbiology labs. In the current process, the specimens are accepted into the lab. These specimens are then sorted and labeled and then they are inoculated onto blood agar medium using sterilized loop. The specimens are then inserted into a dedicated incubator for a 24-hour period. A day later, the lab technicians screen the specimens for positive and negative cultures. In general, most of the cultures are negative and they are manually reported. The organisms for the positive cultures are isolated and suspended in a biochemical fluid. This involves suspension, dilution, vortexing and turbidity measurements resulting in biochemical waste products. The cultures are then subjected to a species identification and antibiotics susceptibility testing exposing the suspensions to multiple reagents. After another 6- to 24-hour incubation period, the findings are interpreted and reported by lab technicians. This entire process generally takes 11 steps and 50 hours to obtain specimen results and the process is labor intensive. 
         [0006]    WIPO Publication No. WO 2009/049171 filed Oct. 10, 2008 and entitled “SYSTEM FOR CONDUCTING THE IDENTIFICATION OF BACTERIA IN URINE” discloses a system for identifying bacteria in urine samples and includes: 1) a disposable cartridge or holder for holding disposable components including a centrifuge tube, two pipette tips with a different volume capacity and an optical cup or cuvette; 2) a sample processor for processing or preparing the urine samples; and 3) an optical analyzer for analyzing the processed urine samples. The disposable cartridge with its four components is used in the sample processor and the optical cup or cuvette, in particular, is used in the optical analyzer. 
         [0007]    In this system of the aforementioned WIPO Publication No. WO 2009/049171 the urine samples are contained within disposable cartridges which hold disposable components, i.e., a centrifuge, two pipette tips with a different volume and an optical cuvette. The cartridges are bar coded and tied in with the patient&#39;s ID. The cartridges are inserted in a magazine which is then inserted into a sample processor which processes the specimens. The prepared specimens are injected into the optical cuvettes which are then inserted into an optical analyzer which analyzes the specimens. The optical analyzer analyses and generates the complete results enabling ultimate treatment of the bacteria. The system does not require a sophisticated operator and gives rapid results. The system increases efficiency, improves workload, saves time and money and is easy to operate. The sample preparation can be performed in parallel with the specimen analysis process and from 1 to 50 specimens can be analyzed simultaneously. 
         [0008]    This system of WIPO Publication No. WO 2009/049171 includes a plurality of disposable cartridges for holding a plurality of disposable components including a centrifuge tube, a first pipette tip with a 1 ml volume; an optical urine sample cuvette, and a second pipette tip with a 0.5 ml volume; a sample processor for receiving the plurality of disposable cartridges and configured to process and prepare the urine sample of each disposable cartridge and to transfer the urine samples into the respective optical cuvette of each of the disposable cartridges; and an optical analyzer for receiving the optical cuvettes containing the processed urine samples and analyzing and generating the specimen results. The entire procedure for processing the urine specimens in the sample processor and analyzing them in the optical analyzer takes about 20 minutes for a single specimen and up to 2 hours for 50 specimens. 
         [0009]    A related method for identifying the type of micro-organism in a urine sample includes the steps of obtaining a urine sample; passing the urine sample through an eleven micron filter; obtaining a 2 ml sample of the filtered urine and placing it into a centrifuge tube; obtaining a 1,000,000:1 dilution of the dissolved materials in the urine retaining bacteria in the urine sample by centrifuging the 2 ml sample at about a 12,000 g-force, decanting about 95% of the fluid in the centrifuge tube, replacing the decanted solution with a saline solution and repeating these steps about five times; transferring the final solution into an optical cup; subjecting the optical cup to an optical analysis having optics which include exciting the urine sample with different wavelengths, collecting and detecting the fluorescent emissions; and directing the fluorescent emissions into a spectrometer which may be part of an optical analyzer of the system of WIPO Publication No. WO 2009/049171. 
         [0010]    The optical analyzer used in the aforementioned WIPO Publication No. WO 2009/049171 may include an optical measurement arrangement for optically analyzing the bacteria in urine samples. Currently, when performing an optical measurement of a signal, which is a result of a light source, e.g., a UV light source, the signal will change with a change in the intensity of the light illumination; however, this change does not reflect a change in the measurement variable, e.g. the bacteria in the sample. Previous attempts for correcting the power changes to signals represented by the intensity of the light in an optical measurement arrangement involved splitting the illumination beam into at least a first split beam and a second split beam and then measuring the changes in the second split beam by using a detector assembly, such as a photodiode or PMT (photomultiplier tube). Although the intensity of the second split beam, which is measured by the detector assembly, may represent a change in the first split beam, this intensity of the second split beam will also be affected by any changes occurring in the detector assembly due to factors such as aging, temperature and spectral and/or intensity responses in the detector assembly. Thus, a correction to the intensity of the signal represented by the first split illumination beam based on the intensity of the second split beam being detected by the detector assembly of the prior art optical measurement arrangements, will introduce errors into the power correction to the intensity signal of the illumination beam of these optical measurement arrangements. 
         [0011]    Examples of optical measurement arrangements are disclosed in U.S. Pat. Nos. 6,515,745; 6,559,941; 6,773,922; 7,206,620; 7,299,079; and 7,303,922. 
         [0012]    There is a need in the art to enhance the power correction to a light source of an optical measurement arrangement by providing a correction signal to the illumination beam that is free from errors existing in the detector assembly used to measure the intensity of the illumination beam generated by the light source. 
       SUMMARY OF THE INVENTION 
       [0013]    The optical measurement arrangement of the present invention has met this need. The optical measurement arrangement of the present invention relates to a device and a method for optimizing the power correction to the light source used as a signal in an optical measurement arrangement. The method includes the steps of: 1) providing a light source for producing a light beam; 2) directing the light beam into a beam splitting device to produce a first split light beam and a second split light beam; 3) directing the first split light beam into a region of interest, e.g. an interrogation area; 4) collecting light from the region of interest and directing it to an optics separation device for separating the first split light beam into several light beams which are detected by the detection elements, e.g. cells of a detector array assembly; 5) while performing steps 3) and 4), directing the second split light beam into a detection element, e.g. cell of the detector array assembly; 6) measuring and assessing the information obtained in the detection elements of the detector array assembly that received the light beams of the first split light beam and the information obtained in the detection element of the detector array assembly that received the second split light beam; and 7) using the information obtained in step 6) to adjust the power for the light beam of the light source and/or to correct the intensity of the light beam of the region of interest. 
         [0014]    The device includes a light source for producing a light beam; a beam splitting device for splitting the light beam into a first split light beam and a second split light beam; an interrogation area for receiving the first split light beam; an optics separation device for separating the light generated from the first split light beam into light beams; a detector array assembly having a plurality of detection elements, e.g. cells for receiving the light beams from the optics separation device and for receiving the second split light beam; and measurement means for assessing the information obtained from the detection elements of the detector array assembly which received the light beams from the optics separation device and the information obtained from the detection element of the detector array assembly which received the second split light beam and for creating an output signal used for adjusting the power for the light beam of the light source and/or for correcting the intensity of the light beams from the interrogation area based on the information obtained from the detection elements of the detector array assembly. 
         [0015]    It is therefore an aspect of the invention to provide an optical measurement arrangement which includes a detector array assembly and a measuring device for measuring and assessing the intensity of a first split beam light represented in several detection elements of a detector array assembly and the intensity of a second split beam light represented in a detection element of the same detector array assembly and using this information to adjust the power for the light beam of the light source and/or to correct the intensity of the light beam of the light source from a region of interest, e.g. an interrogation area, in an optical measurement arrangement. 
         [0016]    It is a further aspect of the invention to provide a method and device for correcting power changes in an optical measurement arrangement by using the same detector array assembly to detect the observed light and to detect the intensity of the illumination of the main light beam of the light source. 
         [0017]    Yet a further aspect of the invention is to provide a method and device for detecting the changes in the intensity of the illumination of the light beam generated by a light source in an optical measurement arrangement, which device has the same characteristics as the detector used to measure the observed signal or signals. 
         [0018]    These and other aspects and advantages of the invention will be made apparent from the following description taken together with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a schematic view illustrating an optical measurement arrangement of the present invention, which optionally, may be used in a system for conducting the identification of bacteria in urine samples; and 
           [0020]      FIG. 2  is a perspective view of an optical analyzer in which the optical measurement arrangement of the invention may be used. 
           [0021]      FIG. 3  is a cross-sectional side view illustrating one of the disposable cartridges of  FIG. 2  and the disposable components including an optics cup; and 
           [0022]      FIG. 4  is a schematic view illustrating in more detail the movement of the light beam through the optics cup of  FIGS. 2 and 3  and through the components of the measurement arrangement of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    The present invention will be described with reference to the accompanying drawings where like reference numbers correspond to like elements. The optical measurement arrangement of the present invention may be used in the optical analyzer described in a system for conducting the identification and quantification of bacteria in urine samples such as that disclosed in the above-discussed WIPO Publication No. WO 2009/049171, filed October 10, 2008, which is incorporated herein by reference in its entirety. 
         [0024]    As stated hereinabove,  FIG. 1  is a schematic illustrating an optical measurement arrangement of the present invention which optionally may be used in the system for conducting the identification of bacteria in urine samples. In this instance, the optical measurement arrangement  100  may be used in the optical analyzer  16  shown in  FIG. 2  and further discussed below. This optical analyzer is also shown and discussed in detail in WIPO Publication No. WO 2009/049171. 
         [0025]    As shown in  FIG. 1 , an optical measurement arrangement  100  includes a light source  102 , a beam splitter device  104 , an interrogation area  106 , a separation optics device  108  and a detector array assembly  110  that has a plurality of detection elements, e.g., cells,  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 ,  126 ,  128  and  130 . 
         [0026]    As shown in  FIG. 1 , a main light beam indicated at L is generated by the light source  102 , which may be any suitable light source, for example, a lamp or laser. The main light beam L is directed into a device which splits the main light beam L into a first split light beam indicated at L 1  and a second split light beam indicated at L 2 , representing the intensity of the illumination of the main light beam L of light source  102 . This device may be a beam splitter or it may be a fiber optic coupler. The first split light beam L 1  is first directed into the interrogation area  106  which may be a device for measuring fluorescence, transmittance or reflectance of this first split light beam L 1  and then directed into the separation optics device  108  which separates the light coming from the interrogation area indicated at L 3  into a spatial pattern according to wavelength or polarization. An example of a spatial pattern is represented in  FIG. 1  by light rays L 4 , L 5  and L 6 . These light rays L 4 , L 5  and L 6  are directed to and are received by one or more detection elements  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 ,  126 , and  128  of detector array assembly  110 . 
         [0027]    While light rays L 4 , L 5  and L 6  are being received by detection elements  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 ,  126 , and  128 , the second split light beam L 2  is directed to and received by detection element  130  of detector array assembly  110 . The detector array assembly  110  may be a CCD or a photodiode array. Still referring to  FIG. 1 , a measurement device  132  receives the signals L 7 , L 8  and L 9  (the observed light) from detection elements  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 ,  126 , and  128  and also receives the signal L 10  from detection element  130  generated by light beam L 2 , representing the intensity of the illumination of the main light beam L of light source  102 . 
         [0028]    The measurement device  132  then measures and assesses the signal of the observed light in detection elements  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 ,  126 , and  128  and the intensity of beam L 2  of light source  102  in detection element  130  and uses this information to correct the information in cells  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 ,  126 , and  128  for intensity variation of the light beam L generated in light source  102  or adjust the power of light source  102  as indicated by light or signal L 11  which is an output of measurement means  132  and an input to light source  102 . Even though L-L 11  are referred to as light beams, it is to be appreciated that these light beams L-L 11  are converted in a customary manner through the several devices in  FIG. 1  into signals having a certain strength which is equated to the intensity of the respective light beams associated with the several devices of  FIG. 1 . 
         [0029]    From the above, it can be appreciated that a power correction of the optical measurements of the optical measurement arrangement  100  of the present invention may be enhanced by using part of the detector array assembly  110 , i.e. detection element  130  to measure the intensity of the illumination of the main light beam L of light source  102  by directing the second split light beam L 2  into detection  130  of the detector array assembly  110  and using this information based on the intensity of the light source  102  to cell  130  to calculate the corrected value for cells  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 ,  126 , and  128  or to alter the power of the light source  102 . 
         [0030]      FIG. 2  shows one type of optical analyzer  16  in which the optical measurement arrangement  100  of the invention may be used. 
         [0031]    The optical analyzer  16  of  FIG. 2  will now be briefly described. The optical analyzer  16  includes an optics system  44 , a thermal control unit (not shown), a drawer  50  which has a rotatable table  52  which receives, supports, and rotates a magazine  54  containing a plurality of holders  56  for receiving the disposable cartridges  12  in which cups or cuvettes  22  contain the processed urine samples which are to be analyzed, and a bar code reader  58 . 
         [0032]    As can be appreciated, a cartridge  12  that has the cups or cuvettes  22  containing the processed urine sample for optical analysis are placed into the holders  56  of the magazine  54 .  FIG. 2  illustrates the magazine  54  mounted on the rotatable table  52  being loaded into the optical analyzer  16 . In this device, drawer  50  is pulled out manually for the loading and unloading of magazine  54 . Drawer  50  contains the thermal control unit (not shown) and a drive mechanism (not shown). Alignment features on the magazine  54  and drawer  50  allow the operator to orient the magazine  54  properly on the drive mechanism and the thermal control unit when the magazine  54  is loaded onto the rotatable table  52 . Once the drawer  50  and magazine  54  are manually inserted into the optical analyzer  16 , the drive mechanism rotates the magazine  54  at which time a bar code reader station  58  inventories the samples. An operator can access the optical analyzer  16  when a user interface indicates that all the samples in the cups or cuvettes  22  have been analyzed and drawer  50  is prevented from being opened when any of the components of optical analyzer  16  are moving or when the UV light sources of the optics system  44  are on. 
         [0033]      FIG. 2  illustrates the magazine  54  on rotatable table  52  while being positioned within optical analyzer  16 . The optical analyzer  16  further includes a mechanical locking system (not shown) which positions the drawer  50  accurately with respect to the optics system  44 . The drive mechanism is configured to automatically rotate the magazine  54  to position each cartridge  12  into the bar code reader station  58  and into precise alignment with the optics system  44 . A second mechanical locking system (not shown) is used to secure each cup or cuvette  22  in its proper positioning relative to the optics system  44  for optical analysis. 
         [0034]    Reference is now made to  FIGS. 3 and 4  which illustrate in more detail the movement of the light beam through a sample and subsequently through the optical measurement arrangement of the invention.  FIG. 3  shows a cross-sectional side view of one type of disposable cartridge  12  that can be used in the optical analyzer  16  of  FIG. 2  for conducting the identification and qualification of contaminants, e.g., micro-organisms, e.g., bacteria in samples, e.g., urine samples. Disposable cartridge  12  contains and carries several disposable components which include a centrifuge tube  18 , a pipette tip  20  and an optics cup or cuvette  22 . The centrifuge tube  18  is a container that has an elongated body  18   b  with a tapered end indicated at  18   a.  In general, the centrifuge tube  18  initially contains the sample and the pipette tip  20  may be used to dilute the dissolved sample constituents and then transfer the diluted urine sample into the optics cup or cuvette  22  for optical analysis. The disposable cartridge  12  and its disposable components  18 ,  20  and  22  may be made of an ABS plastic material which is easily injection molded and inexpensive to manufacture. 
         [0035]    Still referring to  FIG. 3 , the disposable components  18 ,  20  and  22  are each contained within separate compartments  30 ,  32  and  34 , respectively, of the disposable cartridge  12 . As is shown, the bottom of compartment  32  which receives and carries the pipette tip  20  is closed so that any drip from the pipette tip  20  will not contaminate the surface below the disposable cartridge  12 . Components  18  and  20  are suspended within its respective compartment  30 ,  32  via a lip  40 ,  42 , respectively. Lips  40  and  42  are attached to its respective component  18  and  20 , and are supported by a top surface  45  of disposable cartridge  12 . In a similar manner, optics cup or cuvette  22  is suspended within its respective compartment  34  via a flange  60  of optics cup or cuvette  22  which the flange  60  is supported by the top surface  45  of disposable cartridge  12 . The compartments  30  and  32  are generally cylindrical shaped and extend substantially the length of centrifuge tube  18  and pipette  20 . Compartment  34  for positioning and supporting optics cup or cuvette  22  is substantially enclosed within the disposable cartridge  12  and has a configuration similar to that of optics cup or cuvette  22 . 
         [0036]    The optics cup or cuvette  22  is a container and preferably includes a reflective coating or layer to assist in the optical analysis. In particular, an inner surface of optics cup or cuvette  22  is coated with a reflective material or contains a layer of reflective material. The optics cup or cuvette  22  may be made of a non-reflective material, for example, an ABS plastic material or glass or it may be made of a metallic material, e.g., aluminum. In the latter instance, that is, if the optics cup or cuvette  22  is made of a non-reflective material, it may be coated with or layered with the reflective material. Alternatively, in the manufacturing of the optics cup or cuvette  22 , the layer of reflective material may be incorporated onto the plastic or glass. As shown in  FIGS. 3 and 4 , the optics cup or cuvette  22  includes the lower tapered area indicated at  24  in order to assist with the optical analysis of the specimen, and it is anticipated that the UV-light source provided in an optical analysis be directed into the optics cup or cuvette  22  for the optical analysis of the specimen, more about which is discussed below in relation to  FIG. 4 . 
         [0037]      FIG. 4  shows the movement of the light beam L through a cuvette  22  and the optical measurement arrangement  100  according to the invention. The light beam is generated by the light source  102  and enters into beam splitter  104  to form the first light beam L 1  and the second light beam L 2 . The second light beam L 2  is directed to the detector array  110  as previously discussed. The first light beam L 1  is directed into the cuvette  12  or interrogation area  106 , and subsequently into a biological sample  23  contained therein. For the purpose of discussion, the interrogation area  106  shown in  FIG. 1  also includes the light culminator  107 . This first light beam L 1  can be redirected into the cuvette  12  through the use of a lens, mirror, or any other well known device. The first split beam L 1  contacts the mirror and is redirected into the biological sample as indicated at L 1   a.  The beam L 1   a  contacts the lower tapered area  24 , causing the beam, indicated by L 1   b,  to move through the sample and contact inner wall surface  25 . This contact then causes the light beam to be again redirected, as indicated by L 1   c,  back through the sample. Light beam L 1   c  then contacts the lower tapered area  24  which causes it to be reflected out of the sample, as indicated by L 1   d.  Light generated in the sample is emitted out of the sample, as shown by L 1   e,  into a light culminator  107 . The light culminator  107  collects and redirects the emitted fluorescent light through a series of filters and lens to gather and redirect the light to the separation optics device  108 , as indicated by L 3 , for separating at  108  and subsequent processing through the detector array  110  and the measurement device  132  as discussed above. 
         [0038]    It can be appreciated that the optical analyzer  16  of  FIG. 2  is only one type of analyzer in which the optical measurement arrangement  100  of the present invention may be used and that the present invention may be used in other types of optical analyzers for measuring and correcting power changes when performing optical measurement of a signal which is a result of light illumination. 
         [0039]    The present invention has been described with reference to the preferred embodiments. Obvious modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations.