Patent ID: 8411286

Claim:
A device for measuring a static tilt angle of a voice coil motor, the voice coil motor comprising a movable part for coupling to a lens barrel, the device comprising: a laser transmitter and receiver, the laser transmitter and receiver comprising a surface having a laser emitting point and a laser detection area, the laser emitting point being configured for emitting laser, the laser detection area being configured for detecting laser striking thereon, the laser emitting point being within the laser detection area, a coordinate of the laser emitting point on the surface of the laser transmitter and receiver being (X0, Y0); a fixture opposite to the surface of the laser transmitter and receiver, the fixture comprising a first flat reflective surface opposite to the laser transmitter and receiver, the laser emitted by the laser transmitter and receiver being substantially perpendicular to the first reflective surface, the first reflective surface having a predetermined area, the fixture being configured for supporting the voice coil motor in such a manner that a bottom boundary of the voice coil motor is coincident with the predetermined area, when the static tilt angle of the voice coil motor is zero, the laser being coincident with a central axis of movable part; a reflective component for being positioned on the movable part, the reflective component having a second flat reflective surface facing the laser transmitter and receiver, a normal line of the second reflective surface being parallel to the central axis of movable part, the second reflective surface being for reflecting the laser to the laser detection area, thus forming a light point on the laser detection area, a coordinate of the light point on the surface of the laser transmitter and receiver being (X1, Y1), a distance between a point that the laser reaches the second reflective surface and the surface of the laser transmitter and receiver being h, the laser transmitter and receiver being capable of measuring the distance h; and a processor electrically connected to the laser transmitter and receiver and configured for receiving the coordinates (X0, Y0), (X1, Y1) from the laser transmitter and receiver, the processor being configured for calculating a distance s between the laser emitting point and the light point according to a formula s=√{square root over ((X1−X0) 2 +(Y1−Y0) 2 )}{square root over ((X1−X0) 2 +(Y1−Y0) 2 )}, and then calculating the static tilt angle α according to a formula: α=0.5 arctan(s/h).