Electro-Optical Cursor Controller
Original Publication Date: 1985-Apr-01
Included in the Prior Art Database: 2005-Feb-18
A probe is utilized as a pointing device for a computer workstation to continuously read XY coordinates on the flat surface of a pad. The XY coordinates are generated by chromatic filters that disperse light waves such that the probe can read them. The device is constructed in the following manner. Two chromatic filters, having a uniform gradient of transmission in one dimension of a particular wavelength band, are superimposed so that the transmission gradients are at right angles. This results in a composite filter which varies in transmission and composite wavelength in both directions. The example shown in Fig. 1 uses yellow and magenta. Any point on the surface can be defined as the transmission of wavelength 1 and wavelength 2. The chromatic filter 2 (Fig.