| 摘要 |
A matrix-scanning optical keyboard comprising a logical matrix of optical paths between light inlets (3) and outlets (2) with keys disposed on each optical path connecting an inlet to an outlet in such a manner that depressing a key causes a change which can be detected by a scanning driver circuit connected to the light inlets and outlets in order to respond to changes affecting each inlet-to-outlet (3-to-2) coupling by periodically injecting an interrogation signal into each inlet in turn and by inspecting each outlet for the presence of possible changes. The keyboard is capable, for a given emission level, of increasing the sensitivity of the driver circuit to light arriving at the outlets.
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