Rotatable disc, method for adjusting the orientation of the rotatable disc, and application of the rotatable disc

摘要

A rotatable disc (1) comprises a first zone (6) in which a plurality of features (7, 8, 9, 10), e. g. optical filters, are located at uniform angles from each other with respect to an axis of rotation (2) of the disc (1) and a second annular zone (12) formed of pairs (13+17, 14+18, 15+19, 16+20) of adjacent sectors of a first type (13-16) and of a second type (17-20). Each pair has a same total circumferential length, but the sectors of a given type have at least two different circumferential lengths. A method for adjusting the rotational orientation of the disc based on detecting the widths of the sectors is described. IMAGE