Patent ID: 8487256

Claim:
A proximity sensor for detecting a presence of an object within a first distance of an exterior surface of a protective layer of a portable electronic device, comprising: a light emitting device arranged to emit light at a primary frequency in a direction outward and away from the portable electronic device; a light detecting device arranged to detect light at least at the primary frequency; a collimator placed between the light detecting device and the light emitting device, the collimator causing a substantial portion of the light emitted by the light emitting device to impinge the protective layer of the portable electronic device at a low angle of incidence thereby reducing an amount of emitted light that reflects from the interior surface of the protective layer and detected by the light detecting device; a filtering layer applied to the interior surface of the protective layer arranged to filter out frequencies of light other than the primary frequency, thereby substantially reducing the likelihood of the light detecting device from detecting light other than that of the primary frequency; and a uniform transparent structure applied to an inner surface of the filtering layer, the uniform transparent structure having a size and shape in accordance with the proximity sensor, the uniform transparent structure arranged to absorb substantially all light incident thereon, thereby reducing an amount of light detected by the light detecting device not associated with light reflected from the object.