| abstract |
The apparatus and method produce visual sensations by applying low voltages through conductive electrodes to the outside of a person's head, for transmission by natural mechanisms to the nervous system--to entertain or inform a sighted person, or to help a blind person to locate nearby objects. n As to entertainment, the apparatus generates various waveshapes, and an operator directs one or more to the electrodes. The operator also manually varies waveshape parameters such as frequency, amplitude, duty cycle and dc bias--or controls them with automatic sweep devices at selected sweep rates. Various wavetrains are combined at the electrodes or in the person's head for more-elaborate effects. The electrode wavetrains or necessary control signals are also received for playback. n As to information, the apparatus produces coded patterns or even rough analogs of normal visual scenes. As to aiding the blind, the apparatus responds to a sonar signal by placing phosphenes in the perceived visual field roughly where a normal person would see nearby objects. |