| 摘要 |
1,259,588. Facsimile apparatus. WESTERN ELECTRIC CO. Inc. 30 Jan., 1970 [4 Feb., 1969], No. 4541/70. Heading H4F. [Also in Divisions G2 and G4] Apparatus for generating a pattern, character or image comprises a laser 13, a modulator 23 for intensity modulating the beam, a rotatable mirror drum 19 having reflective surfaces 20 for causing the beam to scan and a lens 18 having a focal length which varies in accordance with K#/tan#, where K is a constant and # is the angle between the scanning beam and the axis of the lens. Binary data representing the pattern to be generated is fed from a store 11 to the modulator 23 via a shift register 22. The binary data causes the modulator to switch the beam 16 on or off. A motor 25 rotates the mirror 19 at a constant angular velocity so that the beam scans a photographic plate 12 through a slit 26 in a stationary mask 27. At the end of each line scan, the register 22 actuates a motor 31 which rotates a lead screw 32 to advance a table 33 on which the plate 12 is positioned. To ensure that each bit of data modulates the beam at the correct instant during its scan, a beam splitter 15 produces a second beam 17 which is reflected from a mirror 29 to a plate 34 comprising alternate opaque and transparent strips. The beam 17 is focused by a lens 35 on a photodetector 30 which supplies gating signals to the shift register 22. An interferometer controlling a refractory plate or rotatable mirror is provided to compensate for errors in the incremental movement of the photographic plate 12. The apparatus, which may be used to generate mask patterns for making integrated circuits may also be used as a facsimile reproducer of stored analogue signals. The reflecting facets of mirror drum 19 may each comprise roof-shaped reflector prisms (Figs. 6 and 7, not shown). |
