US Patent 7336368 Optical detecting module and optical detector thereof

An optical detector measuring a movement of an object in a space on a measurement axis comprises a light source, a reflective portion, a detection unit and a converting unit. The light source comprises a resonance chamber, the light source emitting a laser beam toward the object, the laser beam contacting the object and generating a first scattering beam and a reflection beam, wherein a part of the first scattering beam enters the resonance chamber. The reflective portion reflects the reflection beam toward the object, the reflection beam re-contacting the object and generating a second scattering beam and a sub-reflection beam, wherein a part of the second scattering beam and the sub-reflection beam enter the resonance chamber. The detection unit measures an optical-electrical variation in the resonance chamber to generate an electric signal. The converting unit converts the electric signal to a movement on the measurement axis in the space.