Abstract:
An optical element for conveying scattered and image light to several detectors. The optical element may have the properties of a diffractive beam splitter and imaging lens. The detected light may be from an illuminated target. Further, there may be an optical element for conveying scattered light from a target via several zones to specific detectors, respectively. The latter optical element may include a multiple annular zone diffractive structure on a hybrid lens.

Description:
BACKGROUND  
       [0001]     The invention pertains to optical arrangements, and particularly to those involving scattered light. More particularly, the invention pertains to collecting information from scattered light and images.  
       SUMMARY  
       [0002]     The invention is an optical system for obtaining data from a region of interest with imaging and scattering detection and measurements of light. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0003]      FIG. 1  is an optical imaging channel for determining particle diameter and flow rate;  
         [0004]      FIG. 2  is an optical scattering channel for determining particle type;  
         [0005]      FIG. 3  is a combination optical imaging and scattering channel; and  
         [0006]      FIG. 4  is an optical scattering device having a multiple zone diffractive structure. 
     
    
     DESCRIPTION  
       [0007]     There may be system that collects both scattering and imaging information of an event such as in a cytometer flow channel and that of a cell, for example, a white or red blood cell. For instance, in cytometery, some of the goals may include a classification and counting of cell types along with a measurement of cell volume. An all optical approach to these goals may be achieved by measuring light scattered off of a cell at various angles along with imaging the cell to determine its diameter, and possibly other properties. The imaging and scattering may be accomplished with two independent optical systems, as illustrated in  FIGS. 1 and 2 , respectively. However, with the present approach, the scattering and imaging may be accomplished with one independent optical system, as illustrated in  FIG. 3 . The use of a diffractive or hybrid (i.e., diffractive-refractive) optical element may permit one to achieve an optical train that accomplishes both imaging and scattering.  
         [0008]      FIG. 1  illustrates an optical imaging channel or train  10  that may be used for determining a diameter and flow rate, for example, of blood cells  12  (or other particles) in a flow channel  13 . An imaging lens  14  may focus light  15  from a cell  12  on an imaging detector  16 . Detector  16  may be an array of photodetectors or some other mechanism for image detection. Lens  14  and detector  16  may be aligned along an optical axis  17 .  
         [0009]      FIG. 2  illustrates an optical scattering channel or train  20  that may used for determining a type, and/or other property, of blood cell  12  (or other particle) in a flow channel  13 . Light  18  scattered off of cell  12  may go through a lens  23  which may operate as a scatter collection lens. Scattered light  18  may be redirected by lens  23  which may proceed on to a detector  21 . Detector  21  may be a photodetector or an array of photodetectors or some other mechanism. Detector  21  may be an annular-shaped detector. Detector  21  may detect FALS (forward angle scattering) and/or SALS (small angle scattering) of light. Detector  19  may be an extinction channel (unscattered by cell  12 ) for light that may be proceeding along optical axis  17 .  
         [0010]      FIG. 3  is a combination scattering and imaging channel or train  30  that may be used for determining a diameter, flow rate and/or type (and/or including possibly other properties) of blood cells  12  (or other particles  12 ) in the flow channel  13 , or items in a region of interest. The particles  12  may be illuminated by a light source  44 . Lens  24  may focus light  15  from a cell  12  on an imaging detector  22  with a double slit. Lens  24  may be regarded as a diffractive beam splitter channel. Light  15  may be of a plus first order imaging. Detector  22  may consist of an array of photodetectors or some other mechanism for image detection and as a scattering extinction channel. Lens  24  may collect scattered light  18  of a minus first diffracted order which may proceed on to detector  21 . Detector  21  may be a photodetector or an array of photodetectors or some other mechanism. Detector  21  may be an annular-shaped detector. Detector  21  may detect FALS and/or SALS light. Detector  22  may be part of an extinction channel for light that may proceed along optical axis  17 . Detectors  16 ,  19 ,  21  and  22  may also be regarded as a part of an imaging channel, an extinction channel, a FALS/SALS scattering channel and/or an imaging channel with a double slit, respectively. Signals from the detectors  21  and  22  may go to a processor  45  for analysis of signals and outputs of information about the target  12 .  
         [0011]     An angular scatter collection channel  40  ( FIG. 4 ) may be implemented to collect efficiently and compactly angular zones  31 ,  32  and  33  of scattered light from a region of interest such as a flow channel  13  having cells  12  (or other particles) flowing in the channel. The region of interest or target may be illuminated by a light source  42 . The flow channel  13  may be a part of a cytometer. Collected light may be redirected onto small detectors  35 ,  36  and  37  that are of similar area and close together. With a three angular zone diffractive surface structure on a hybrid lens  38 , one may be able to collect annular zones  31 ,  32  and  33  of scattered light from the region of interest, and focus these different zones onto adjacent detectors  35 ,  36  and  37 , respectively. By using the singular optical element  38  which combines both focusing and grating properties, a complete or nearly complete annular scattered region  31 ,  32 ,  33  may be captured and redirected onto a linear (or other configuration) detector array  35 ,  36 ,  37  in a compact module.  
         [0012]     Each angular zone  31 ,  32  and  33 , of the diffractive surface structure of optical element  38  may have an associated linear term (grating) that redirects captured scattered light over the respective region to a lateral position near an optical axis  39  of lens  38 . Lens  38  may also serve to focus the captured scattered light. Each capture zone may be redirected by the diffractive structure on lens  38  in that particular zone to a different lateral position in a detector array plane  41  that may support, for instance, detectors  35 ,  36  and  37 . The detectors may be of equal area, close together and/or compact with a maximum energy capture. Signals from detectors  35 ,  36  and  37  may go to a processor  43  for analyses of the signals, and an output of information about the targets  12 . The light collection regions may include an extinction zone  31 , a size zone  32  and a structure zone  33  which have scattered light directed to detectors  35 ,  36  and  37 , respectively. Zone  33  may be the outermost zone from axis  39 , as conveyed by the diffractive structure on lens  38 . Zone  31  may be the intermost zone relative to axis  39 , and zone  32  may be the intermediate zone between zones  31  and  33  relative to axis  39  of lens  38 . There may instead be more or less than three zones in the angular scatter collection channel  40 .  
         [0013]     In the present specification, some of the matter may be of a hypothetical or prophetic nature although stated in another manner or tense.  
         [0014]     Although the invention has been described with respect to at least one illustrative example, many variations and modifications will become apparent to those skilled in the art upon reading the present specification. It is therefore the intention that the appended claims be interpreted as broadly as possible in view of the prior art to include all such variations and modifications.