| 摘要 |
Pointing device 1 such as an optical mouse comprises laser 2 for illuminating a front surface of glass substrate 6 at a predetermined angle of incidence (substrate 6 having a rear surface as well as the front surface and being transparent to the wavelength of the incident light), lens 3, optical detector 4 and legs/feet 7 in contact with substrate 6. Light reflected from front and rear surfaces of substrate 6 passes through aperture 5 and detector 4 records a speckle pattern. Feet 7 in contact with substrate 6 electrically charge the front surface of substrate 6 through friction to attract dust in order to increase the signal intensity of the speckle pattern to improve tracking performance on smooth surfaces. Aperture 5 allows speckle light from the front and rear surfaces of substrate 6 to be superimposed on detector 4 (40c, fig. 4C). |
