Patent ID: 8760759

Claim:
A focusing device for use with a night vision optical device, the focusing device comprising: an objective lens assembly positioned at a first or second focus position from an imaging device; and a binary focus controller, coupled to the objective lens assembly, configured to translate the objective lens assembly relative to the imaging device to either the first or second focus position, wherein the objective lens assembly is translated to either the first or second focus position in response to an orientation of the night vision optical device, the binary focus controller includes a line of sight (LOS) sensor coupled to the night vision optical device, the LOS sensor configured to determine a tilt angle of the night vision optical device relative to a horizontal LOS, the tilt angle corresponding to the orientation of the night vision optical device, the LOS sensor includes a pendulum mass coupled to the night vision optical device via a pendulum arm, the pendulum arm rotating responsive to the orientation of the night vision optical device, wherein the tilt angle is determined based on a rotation of the pendulum arm, and a tilt angle detector including: a potentiometer having first and second terminals coupled to a voltage source, a wiper of the potentiometer coupled to the pendulum arm and an output terminal, wherein an output voltage at the output terminal is varied due to rotation of the wiper coupled to the pendulum arm, and the tilt angle is determined based on the output voltage.