Method And System For Optical Measurements Of Contained Liquids Having A Free Surface

Abstract

The present invention is an optical measurement system for measuring a liquid sample within a well. The system comprises a light source configured to transmit light though the well, a detector configured to measure optical signals derived from the transmitted light, and a tunable optical element. The tunable optical element is positioned between the light source and the well. The tunable optical element is operable to shape the light to compensate for distortions induced by a surface of the liquid sample. The detector is preferably located below the well for receiving a forward scatter signal indicative of at least one characteristic of the particles within the liquid sample.

1 . (canceled) 
     
     
         2 - 20 . (canceled) 
     
     
         21 . An optical measurement system for measuring at least one characteristic of particles within liquid samples, comprising:
 a microplate having a plurality of wells positioned in a two-dimensional arrangement;   a light source for transmitting an input beam toward a free surface of a liquid sample in one of the plurality of wells and generally parallel to a central axis of the one of the plurality of wells;   a tunable optical element located between the light source and the free surface of the liquid sample, wherein the tunable optical element is operable to alter the shape of the input beam between a first shape resulting in the input beam not being collimated and a second shape resulting in collimating the input beam to compensate for a distortion associated with the free surface of the liquid sample;   a detector located below the one of the plurality of wells for receiving a forward scatter signal indicative of at least one characteristic of the particles within the liquid sample in the one of the plurality of wells; and   an input-beam attenuator to inhibit a transmitted portion of the input beam from impinging upon the detector, the transmitted portion of the input beam being the portion of the input beam that has transmitted through the liquid sample.   
     
     
         22 . The optical measurement system of  claim 21 , wherein the input-beam attenuator is a beam block located adjacent to the detector and below a bottom surface of the one of the plurality of wells. 
     
     
         23 . The optical measurement system of  claim 21 , wherein the input beam causes a fluorescence signal to be emitted from the particles, the detector further receiving a fluorescence signal indicative of at least one characteristic of the particles within the liquid sample. 
     
     
         24 . The optical measurement system of  claim 21 , wherein the particles include bacteria and the at least one characteristic indicated by the forward scatter signal is the amount of bacteria within the liquid sample. 
     
     
         25 . The optical measurement system of  claim 21 , further including at least one optical fiber to gather additional signals related to particle characteristics from a side or a top of the one of the plurality of wells, the optical fibers providing the additional signals to the detector. 
     
     
         26 . The optical measurement system of  claim 21 , further including a controller coupled to the tunable optical element, the controller for tuning optical parameters associated with the tunable optical element so as to alter the shape of the input beam. 
     
     
         27 . The optical measurement system of  claim 26 , wherein the controller receives information from the detector for tuning the optical parameters so as to properly compensate for the distortion associated with the free surface. 
     
     
         28 . The optical measurement system of  claim 26 , wherein the controller receives information associated with the free surface of the liquid sample for tuning the optical parameters to properly compensate for the distortion associated with the free surface. 
     
     
         29 . The optical measurement system of  claim 21 , wherein the tunable optical element is at least one of a group consisting of a mechanically actuated adjustable lens, an electronically shaped lens, and a spatial light modulator. 
     
     
         30 . The optical measurement system of  claim 21 , wherein each of the plurality of wells has an elongated shape having a top for optical access of the input beam and a bottom. 
     
     
         31 . The optical measurement system of  claim 21 , wherein each of the plurality of wells has a shape having a diameter substantially the same as a length of the shape, and wherein the wells each have a top for optical access of the input beam and a bottom. 
     
     
         32 . A method of determining at least one characteristic of particles within a liquid that is contained in a well of a plurality of wells arranged in an array in a microplate, comprising:
 transmitting a light beam toward a free surface of the liquid in one of the plurality of wells;   prior to the light beam impinging on the free surface, altering a shape of the light beam via a tunable optical element, between a first shape resulting in the input beam not being collimated and a second shape resulting in collimating the input beam to result in a substantially focused beam shape within the liquid in the well after the input beam has been subjected to optical distortions at the free surface;   attenuating the input beam at a location before a detector; and   receiving forward scatter signals at the detector, the forward scatter signals being indicative of at least one characteristic of the particles.   
     
     
         33 . The method of  claim 32 , wherein the particles include bacteria and the at least one characteristic indicated by the forward scatter signal is the amount of bacteria within the liquid sample. 
     
     
         34 . The method of  claim 32 , further comprising gathering additional signals related to particle characteristics from a side or a top of the one of the plurality of wells via an optical fiber; and providing the additional signals to the detector. 
     
     
         35 . The method of  claim 32 , further comprising tuning optical parameters associated with the tunable optical element so as to alter the shape of the input beam via a controller. 
     
     
         36 . The method of  claim 35 , wherein the controller receives information from the detector for tuning the optical parameters to properly compensate for the distortion associated with the free surface. 
     
     
         37 . The method of  claim 35 , wherein the controller receives information associated with the free surface of the liquid sample for tuning the optical parameters so as to properly compensate for the distortion associated with the free surface. 
     
     
         38 . The method of  claim 32 , wherein the tunable optical element is at least one of a group consisting of a mechanically actuated adjustable lens, an electronically shaped lens, and a spatial light modulator. 
     
     
         39 . The method of  claim 32 , wherein each of the plurality of wells has an elongated shape having a top for optical access of the input beam and a bottom. 
     
     
         40 . The method of  claim 32 , wherein each of the plurality of wells has a shape having a diameter substantially the same as a length of the shape, and wherein the wells each have a top for optical access of the input beam and a bottom.