A photodetector for an optical encoder has plural sets of segmented photodiodes, each set of which is made by two adjoining segmented photodiodes capable of coping with a scale slit having a reference resolution. Output lines of the two adjoining segmented photodiodes are connected together in each set of the photodiodes. These output lines are connected to output lines of the corresponding segmented photodiodes in the other sets. The two adjoining segmented photodiodes function like one segmented photodiode, and thereby, the resolution of the applied scale slit is made 1/2 of the reference resolution. Thus, this photodetector easily copes with a scale slit having a half resolution of the reference resolution at low cost only by modification of wiring without changing any configuration of the segmented photodiodes.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a Continuation of co-pending application Ser. No. 10/874,545 filed on Jun. 24, 2004, now abandoned, and for which priority is claimed under 35 U.S.C. .sctn. 120. application Ser. No. 10/874,545 claims priority under 35 U.S.C. .sctn. 119 based on Japanese Application No. 2003-182403, filed Jun. 26, 2003. The entire contents of each of these applications are hereby incorporated by reference.
