Roland Green of Madison, Wis. has received US Patent No. 7,083,975, “Microarray synthesis instrument and method.” The patent claims a flow cell that reduces the undesired reflection of illumination during DNA synthesis by constructing flow cell structures with materials that have similar refractive indexes as that of the solution that is in the oligomer synthesis chamber during the illumination period and/or constructing certain flow cell structures or covering the structures with a layer of a material that has a high extinction coefficient.