Document Type and Number:
Japanese Patent JPS5044827
Kind Code:
A
Abstract:
In a film projector of the type wherein film advance is controlled by pulse signals generated by a tape recorder or the like, a protective filter is automatically inserted into the optical path between the projection lamp and the film when the time interval between successive pulse signals exceeds a predetermined time limit. The filter is automatically removed from the optical path only when two successive time intervals have a duration less than a predetermined duration.
Application Number:
JP9427573A
Publication Date:
April 22, 1975
Filing Date:
August 24, 1973
Export Citation:
International Classes:
G03B21/16; G03B21/38; G03B21/42; G03B31/04; (IPC1-7): G03B31/00