| 摘要 |
An optical film encoder for recording discrete data bits on a length of film, includes a single light source capable of receiving electrical current to produce artificial light; at least two light emission openings positioned to individually emit artificial light produced by the light source, to record respective data bits on the length of film; a light intensity-reducing filter positioned to reduce the intensity of artificial light that can be emitted from one of the openings, but not from the other opening; and a current limiting device capable of reducing the intensity of artificial light produced by the light source to allow the filter to reduce the intensity of artificial light that can be emitted from the one opening at least sufficiently to prevent the light from recording a data bit on the length of film, whereby only the light to be emitted from the other opening will record a data bit on the length of film.
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