Patent ID: 8547477
Filing Date: 2013-10-01
Classification: G03B,H02K

Abstract:
1. A method to achieve a precise timing of a shutter of a digital camera, which can be used also for a controllable aperture, comprising the following steps: (1) providing a shutter system comprising at least one blade, a linear motor, comprising two coils, wrapped around a fixed iron and at least one magnet fastened on a movable device, which is mechanically connected to all blades, and a read-out circuit to measure a difference of inductance of both coils; (2) modulating currents driving the linear motor in order to move the blades to target position; (3) measuring a signal corresponding to the difference of inductance of both coils wherein a sample-and-hold technique is used to improve the read-out of the measurement signals representing the difference of inductance of both coils; (4) comparing a signal defining the difference of inductance measured with a signal defining a target value; (5) moving entirety of shutter blades to target position according to difference of target signal to signal defining the difference of inductance; and (6) reaching the target position if a target signal is equal to the signal corresponding to the difference of inductance measured.