The present invention relates to a chain saw having a chain bar portion extending forwardly from a main body. The support element penetrates through the fixed base and can slide linearly inside the fixed base for position adjustment. Such longer effective lengths can then be cutably formed into slats of various sizes. Then, a passivation layer is deposited and patterned to form contact holes exposing the drain electrode, the gate pad and the data pad, respectively. The method according to this invention can be applied to the extraction of xanthophylls or others beside lutein. If a section is discovered to be missing or altered, subsequent processing of data items of the data set is prevented.