| 摘要 |
<p>A token for use in a vending machine consists of a plastic card having at least one pair of side-by-side holograms embossed thereon. A token reader includes means to guide a token into the path of a readout beam. When two photodetectors positioned at predetermined spaced locations receive equal-amplitude first order beams from an illuminated pair of holograms, an electrically-operated plunger in the token reader operates to obliterate the pair of holograms on the token, and then a signal from a third photodetector in the token reader enables an output signal for operating the vending machine.</p> |
