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US 4,422,083 AGranted
System and method for producing artwork for printed circuit boards
AssigneeAmerican Hoechst Corporation
InventorsDon B. Neumann, Lyle K. Norton, Eric V. Olson
Life of this patent
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Abstract
Laser imaging system for imaging printed circuit artwork on an output medium such as a photosensitive film, a glass plate or a printed circuit board. The laser beam scans the output medium and is modulated in accordance with the image to be formed. A correction signal is applied to the modulator to maintain substantially uniform exposure across the output medium notwithstanding variations in the velocity of the beam.
Claims4
In a system for forming an image on an output medium in accordance with an input signal:
- means for providing a beam of coherent radiation, means for modulating the beam in accordance with the input signal, means including a rotating reflector for deflecting the modulated beam to scan the same along a substantially straight line across the output medium, and means for applying a correction signal to the means for modulating the beam to adjust the intensity of the beam to reduce the intensity of the beam toward the ends of the scan line and maintain a substantially uniform exposure across the output medium notwithstanding variations in the velocity of the beam.
In a system for producing printed circuit artwork:
- means for providing a beam of coherent radiation, means for modulating the beam in accordance with the artwork, means for holding an output medium, means including a rotatively driven reflector having a substantially constant angular velocity for deflecting the beam to effect scanning of the same across the output medium, and means for adjusting the intensity of the beam to maintain a substantially uniform exposure across the output medium notwithstanding variations in the linear velocity of the beam in scanning the medium, said means for adjusting the intensity of the beam including means responsive to the position of the beam for applying a correction signal to the means for modulating the beam to reduce the intensity of the beam when the beam is toward the ends of its scan.
Dependencies are inferred from the claim text.