Optical navigation system and method of estimating motion

• Main Authors: SAI MUN LEE, THINESHWARAN G KRISHNAN, YAT KHENG LEONG
• Format: Patent
• Language: English
• Published: 15.06.2011
• Subjects: CALCULATING; COMPUTING; COUNTING; ELECTRIC DIGITAL DATA PROCESSING; PHYSICS

An optical navigation system 100 and method of estimating motion use a plate 236 with an aperture 244, a photodetector 242 and an optical system 240 for optical lift detection. The optical system comprises a first prism 246 to refract input light through the aperture 244, a second prism 248 to refract light reflected back through the aperture from a target surface 106, and a third prism 250 to receive light from the second prism and to refract it towards the photo detector 242. The prisms can be triangular prisms. The system further comprises a light source 214, for example a light emitting diode (LED) or a vertical-cavity surface emitting laser (VCSEL), to generate light, said input light being a portion of said light; and an image sensor 218, such as charge-coupled device (CCD) or complementary metal oxide semiconductor (CMOS), to receive another portion of light reflected from the target surface and configured to generate frames of image data for motion estimation. The system comprises an optical guide structure 216 to separate said light from said input light. The current invention provides a separate sensing mechanism to detect when an optical mouse is lifted from a target surface.