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1. (WO2001037040) DUAL MOTOR RECIPROCATING BELT SHUTTER

Pub. No.:    WO/2001/037040    International Application No.:    PCT/US2000/042217
Publication Date: Sat May 26 01:59:59 CEST 2001 International Filing Date: Sat Nov 18 00:59:59 CET 2000
IPC: G03B 9/30
G03B 9/38
Applicants: LOCKHEED MARTIN CORPORATION
Inventors: BALOPOLE, Hervey, L.
FRAMPTON, Victor
LANGELLA, Anthony
MATHEWS, Bruce
Title: DUAL MOTOR RECIPROCATING BELT SHUTTER
Abstract:
A system and method are provided for exposing an imaging medium. The method uses a focal plane shutter system (100) with two reversible motors controlled by a servo control processor. A belt connects the motors. One end of the belt is attached to a shaft of the first reversible motor. The other end of the belt is connected to a shaft of the second reversible motor. In the belt (230), there are a plurality of fixed width slits. The servo control processor selects one of the fixed width slits according to a desired exposure time setting. The two reversible motors move the belt during an imaging cycle. During the imaging cycle, the first motor winds the belt around its shaft. The second motor simultaneously unwinds the belt from around its shaft. The servo control processor controls the motors to accelerate the selected slit up to a constant imaging medium traversal speed. The constant traversal speed is also determined by the desired exposure time setting. The selected slit is traversed across the imaging medium at the constant imaging medium traversal speed. After fully exposing the imaging medium, the selected slit is decelerated to a resting position. Motor direction is reversed for both motors in the next imaging cycle. The sequence of accelerating the selected slit, traversing the imaging medium at constant speed, decelerating the selected slit (232), and reversing the motors, is repeated until a new slit is selected.