| 摘要 |
<p>The storage of digital information on a transparent film is located with accuracy by using a film with indentation codings along the outer edges to identify a position. The transparent film (1) has 10 mm wide coding sections (3) along each edge. Each metre of film is identified by a longitudinal line code (4) consisting of surface indentation bars arranged to generate a code number. For example, one section may contain coding indicating 1379 meters. Each code block is preceded by an identification mark (5) and followed by an end of block mark (6). An additional mark (7) is used for film alignment. Two optical scanning heads are located on opposite sides of the film such that bi-directional motion of the film is possible.</p> |
