CONTACT PRINTING WITH COHERENT LIGHT.
TECHNICAL OPERATIONS INC BURLINGTON MASS
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The high degree of collimation and the high energy densities that can be simultaneously obtained from the output of a laser make it an attractive proposition as a light source in contact printers. However, special problems do arise in such a system mainly from the high degree of spatial and time coherence of the laser output. These properties cause deleterious interference and diffraction effects in many printing systems. Experiments are described using a He-Ne gas laser as a light source associated with standard printing frames and continuous drum printers. The troublesome effects, particularly the interference fringes, are illustrated and a method is shown for eliminating these effects through the introduction of a suitable liquid between the emulsions. Recommendations are made for 1 feasibility study with improved optical equipment to obtain high resolution, 2 experimenting with Kalvar and diazo-type materials using the nitrogen gas laser as a source, 3 experimenting with the diazo-type material that has recently been sensitized in the green region of the visible spectrum, and 4 more intensive study of the effect of coherence upon exposure. Author