EP 0731934 A1 19960918 - EXPOSURE CONTROL SYSTEM USING PULSE WIDTH MODULATION
Title (en)
EXPOSURE CONTROL SYSTEM USING PULSE WIDTH MODULATION
Title (de)
SYSTEM ZUR BELICHTUNGSSTEUERUNG UNTER VERWENDUNG VON PULSBREITENMODULATION
Title (fr)
SYSTEME DE COMMANDE D'EXPOSITION A L'AIDE D'UNE MODULATION DE LARGEUR D'IMPULSIONS
Publication
Application
Priority
- US 9506792 W 19950526
- US 25043494 A 19940527
Abstract (en)
[origin: WO9533226A1] An automatic exposure control system for photographic apparatus utilizing a direct current motor to drive a shutter. The exposure control system evaluates the voltage level determined by a voltage source by driving the direct current motor in a reverse direction to provide a load on the voltage source and, based on the voltage level, transmits a pulse width modulated pulse train. The exposure control system alters the duty cycle of the pulse train to provide a predetermined constant average voltage to the direct current motor. Once exposure is complete, the pulse width of the pulse train is increased to one hundred percent of the period and the direction of current flow through the motor is made negative so that the shutter is driven closed at a maximum speed.
IPC 1-7
IPC 8 full level
CPC (source: EP)
Citation (search report)
See references of WO 9533226A1
Designated contracting state (EPC)
DE FR GB IT
DOCDB simple family (publication)
DOCDB simple family (application)
US 9506792 W 19950526; EP 95921488 A 19950526