Recognition of finger position on curved surfaces in Braille displays

Abstract: For the sensing and recognition of the actual finger position in the special case of curved plastic surfaces used in Braille displays, a capacitive principle has been developed employing Finite Element simulation. The simulated self-capacitance principle showed better sensitivity than the mutual capacitance principle and thus was used for the realization of a demonstrator. The according signals can be processed with a commercial electronic circuit based on charge transfer technology. Sensitivity and resolution allow the recognition of finger position even at high finger velocity, i.e. reading speed of experienced blind Braille readers. In the experimental set-up, fingers even at distances of some ten millimeters could be detected, thus opening the possibility of gesture recognition in the future.