| 摘要 |
1,202,617. Photographic apparatus. GERBER SCIENTIFIC INSTRUMENT CO. May 29, 1968 [Dec.22, 1967], No.25636/68. Heading G2A. A graphic design is produced by exposing a photo-sensitive surface, e.g. to produce a mask for making circuit boards or integrated circuit elements, the exposure comprising projecting light energy on to a plurality of discrete spots located along a given line, moving the line in successive passes over a photo-sensitive surface, and selectively varying the amount of light energy projected on to each of the spots as the line is moved relative to the photo-sensitive surface. In one embodiment, a cathode ray tube 38 is mounted on an X-Y plotter consisting of stepping motors 22, 34 and lead screws 20, 30, and light is focused by lens system 52 on to photo-sensitive surface 12. The cathode ray tube beam scans over an apertured mask having two rows of apertures, the apertures in one row being staggered with respect to the other row so that during scanning a continuous line may be generated. The beam is switched on or off adjacent each aperture under the control of a computer 54 and associated input device 56 such as a punched paper or magnetic tape reader. The focusing lens may be omitted and the photo-sensitive surface disposed close to the tube faceplate. The cathode ray tube may have a single beam or a multiple beam tube with associated beam switching devices may be used. In further embodiments a bundle of fibre optics is used to conduct a pattern from the faceplate of a cathode ray tube, Fig.10 (not shown), or from a plurality of light sources, Fig.8 (not shown), a lens being used to focus the end of the bundle on to the photo-sensitive surface. |
