Patent ID: 8061204

Claim:
An accelerometer, comprising: a substrate having a surface, a movable electrode mounted on the surface of the substrate, being movable along an axis substantially parallel to the surface of the substrate in response to acceleration acting thereon, a light-permeable region defined in the movable electrode, a plurality of photosensitive regions and a plurality of non-photosensitive regions defined in the surface of the substrate, the photosensitive regions and the non-photosensitive regions being spatially separated, each of the photosensitive regions comprising a photo-detector, a first cantilever beam and a second cantilever beam respectively connected to opposite sides of the movable electrode and configured for supporting a portion of the movable electrode over the surface of the substrate, the two cantilever beams mounted on the surface of the substrate and aligned along an axis perpendicular to a lengthwise direction of the light permeable region, a first resilient element connected between the first cantilever beam and the moveable electrode and a second resilient element connected between the second cantilever beam and the moveable electrode, the two resilient elements being aligned perpendicular to an extension axis of the photo-detectors, a base having a receiving space defined therein and a cover plate covering the opening of the receiving space, the receiving space comprising a bottom surface on the base, and the substrate and the movable electrode received in the receiving space, and a light source die bonded on the bottom surface, wherein the light-permeable region overlies only a portion of one of the non-photosensitive regions when the accelerometer is at rest, and the light-permeable region overlies a portion of at least one of the photosensitive regions when the accelerometer is subjected to acceleration, such that the corresponding photosensitive region generates an output current.