| 摘要 |
Apparatus for producing images from data provided in digital form. The images may be in monochrome or colour. Laser light beams are focused on to a photographic film (39), and are modulated by electro-optical modulators (19, 20, 21) in accordance with the digital information to produce the image. Stability of each laser beam is ensured by sampling the laser output, comparing a signal derived from the sample of the laser beam by a photosensor (16, 17, 18) with a reference signal(33, 34, 35), and using the difference between the compared signals as one control of the modulator associated with the laser beam. The laser beams can be combined by an arrangement of mirrors (22, 28) and dichroic filters (23, 24), or by using bundles of optical fibres. If optical fibres are not used, the combined beams are converted into a non-coherent beam by a diffusing plate (29) or a cylindrical glass beam mixer, and are then focused on to small pixels of the photographic film (39). |
