Correction for illumination non-uniformity during the synthesis of arrays of oligomers

An apparatus for synthesizing arrays of oligomers such as DNA probes and polypeptides, the apparatus comprising:

• (i) a flow cell having one or more reaction chambers in which monomer addition reactions can be conducted;
• (ii) a light source providing a light beam;
• (iii) an array of optical elements placed to receive the light beam from the light source and arranged such that each element of the array can be positioned to direct light along an optical axis or to not direct light along the optical axis;
• (iv) projection optics capable of receiving the light reflected from the array of optical elements along the optical axis and imaging the pattern of the optical elements onto the flow cell;
• and
• (v) an optical element switch mechanism capable of adjusting the durations of on and off positions of each optical element during one protection group deprotection period to correct for nonuniformity in illumination intensity of the light that the projection optics project onto the flow cell.

An apparatus for synthesizing arrays of oligomers such as DNA probes and polypeptides, the apparatus comprising:

• (i) a flow cell having one or more reaction chambers in which monomer addition reactions can be conducted;
• (ii) a light source providing a light beam;
• (iii) an array of optical elements placed to receive the light beam from the light source and arranged such that each element of the array can be positioned to direct light along an optical axis or to not direct light along the optical axis;
• (iv) projection optics capable of receiving the light reflected from the array of optical elements along the optical axis and imaging the pattern of the optical elements onto the flow cell;
• and
• (v) a lithographic mask placed between the projection optics and the flow cell with different areas of the mask darkened to different gray scales to correct for nonuniformity in illumination intensity of the light that the projection optics project onto the flow cell.