Method and apparatus for aligning microbeads in order to interrogate the same

Abstract

A method and apparatus are provided for aligning optical elements or microbeads 8 , wherein each microbead has an elongated body with a code embedded therein along a longitudinal axis thereof to be read by a code reading device. The microbeads 8 are aligned with a positioning device (or cell) 500 having a plate or platform 200, 1252 with grooves 205, 1258 so the longitudinal axis of the microbeads is positioned in a fixed orientation relative to the code reading device. The microbeads 8 are typically cylindrically shaped glass beads having a diffraction grating-based code embedded in the bead 8 disposed along an axis, which requires a predetermined alignment between the incident code readout laser beam and the code readout detector in two of three rotational axes. The geometry of the grooves 205 are designed to allow for easy loading and unloading of beads from a cell, and the grooves 205 may be straight or curved. Also, the cell may be segmented into regions each associated with a different reaction or used for a different identification process/application, and may have many different geometries depending on the application.

1 . A method for aligning microbeads to be read by a code reading or other detection device, comprising the step of: 
 providing microbeads to a positioning device, each having an elongated body with a code embedded therein along a longitudinal axis thereof;    aligning the microbeads with the positioning device so the longitudinal axis of the microbeads is in a fixed orientation relative to the code reading or other detection device.    
     
     
         2 . A method according to  claim 1 , wherein the positioning device is a plate having a multiplicity of grooves therein.  
     
     
         3 . A method according to  claim 1 , wherein the method includes agitating the plate to encourage the alignment of the microbeads in the grooves.  
     
     
         4 . A method according to  claim 1 , wherein the microbeads are cylindrically shaped glass beads between 25 and 250 microns in diameter and between 100 and 500 microns long.  
     
     
         5 . A method according to  claim 1 , wherein the microbeads have a holographic code embedded in a central region thereof.  
     
     
         6 . A method according to  claim 1 , wherein the code is used to correlate a chemical content on each bead with a measured fluorescence signal.  
     
     
         7 . A method according to  claim 1 , wherein each microbead is substantially aligned in relation to its pitch and yaw rotational axes.  
     
     
         8 . A method according to  claim 1 , wherein the plate has a series of parallel grooves having one of several different shapes, including square, v-shaped or semi-circular.  
     
     
         9 . A method according to  claim 1 , wherein the plate is an optically transparent medium including boro-silicate glass, fused silica or plastic, and the grooves are formed therein.  
     
     
         10 . A method according to  claim 1 , wherein the grooves have a depth that is dimensioned to be at least the diameter of the microbeads, including at least 110% of the diameter of the microbead.  
     
     
         11 . Apparatus for aligning microbeads to be read by a code reading device, comprising: 
 a positioning device for aligning microbeads, each microbead having an elongated body with a code embedded therein along a longitudinal axis thereof, so the longitudinal axis of the microbeads is positioned in a fixed orientation relative to the code reading device.    
     
     
         12 . Apparatus according to  claim 11 , wherein the positioning device is a plate having a multiplicity of grooves therein.  
     
     
         13 . Apparatus according to  claim 1 , wherein the apparatus includes means for agitating the plate to encourage the alignment of the microbeads in the grooves.  
     
     
         14 . Apparatus according to  claim 1 , wherein the microbeads are cylindrically shaped glass beads between 25 and 250 microns in diameter and between 100 and 500 microns long.  
     
     
         15 . Apparatus for aligning an optical identification element, comprising: 
 the optical identification element having an optical substrate having at least a portion thereof with at least one diffraction grating disposed therein, the grating having at least one refractive index pitch superimposed at a common location, the grating providing an output optical signal when illuminated by an incident light signal, the optical output signal being indicative of a code, and the optical identification element being an elongated object with a longitudinal axis; and    an alignment device which aligns the optical identification element such that said output optical signal is indicative of the code.    
     
     
         16 . Apparatus according to  claim 15 , wherein the alignment device is a plate having a multiplicity of grooves therein.  
     
     
         17 . Apparatus according to  claim 15 , wherein the plate is a disk and the multiplicity of grooves are concentric circles or a spiral.  
     
     
         18 . Apparatus according to  claim 15 , wherein the alignment device is a tube having a bore for receiving the optical identification element.