Optisch opneemstelsel met compacte afmetingen voor gebruik met opische schijven van verschillende dikten.

摘要

The reader has an optical block (230) between objective lens (240) and beam splitter (220). The optical block has two regions (230-1, 230-2) operating in two electrically switchable modes. The central region (230-1) is optically transmissive in one or the other of the two modes, while the outer region (230-2) is non-transmissive in the first mode and partially transmissive in the second mode.