MERIDEN, Conn., Aug. 25 -- In a move to strengthen its position as a provider of biochips and microarray analysis tools, Packard BioScience Co. will purchase a unit of GSI Lumonics Inc.'s GSLI Life Sciences unit for $40 million in cash and $80 million in Packard stock. The GSLI Life Sciences unit will provide Packard BioScience with the necessary laser detection and data analysis tools needed to extract results from microarray experiments.