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.