Abstract: An optical pickup with a reflective coating device is provided, including a laser diode (LD), an optical element, and a photo detector integrated circuit (PDIC). The LD emits 1-3 lights with different wavelengths but the same polarization orientation. The beam transmits through the optical element set and focus on a recording media for data reading and writing. The beams are reflected by the recording media, through the optical element set, and detected by the PDIC for signal detection. The optical element set further includes a grating, a reflective coating device, and an objective lens. By using the reflective coating device to change the linear polarization orientation of the emitting light and the feedback light for 90° angle, the relative intensity noise caused by the feedback light in LD can be reduced.

Abstract: A pointing device and method for using the same to measure the motion of that pointing device over a surface is disclosed. The pointing device includes an illumination system, an imaging system, and a controller. The illumination system generates light in a plurality of wavelength bands and illuminates a surface below the pointing device with light from one of the wavelength bands. The imaging system records images of the illuminated surface. The controller selects the wavelength band used to illuminate the surface, compares first and second images recorded by the imaging system at different times when the surface is illuminated with that wavelength band, and determines a displacement indicative of the direction and distance the positioning device moved between the two different times.