Imaging system and method for printed circuit artwork and the like

Claim 2

In a system for use in the manufacture of printed circuit boards: a source of data representative of artwork to be formed on the circuit boards, laser means for providing a beam of coherent radiation, means for modulating the beam in accordance with the data, means for holding an output medium in position to be scanned by the beam, means for effecting scanning of the output medium by the modulated beam to form an image of the artwork on the output beam, means for sensing the position of the beam and providing a reference signal corresponding to the position of the beam on the output medium, means responsive to the reference signal for synchronizing the modulation of the beam with the position of the beam on the output medium, and means for shifting the phase of the reference signal forward in time to compensate for any delay between the generation of the reference signal and the arrival of the modulated beam on the output medium.

Claim 3

In a method utilizing a laser beam to produce artwork for printed circuit boards, the steps of: providing data signals defining the artwork to be produced, modulating the laser beam in accordance with the data signals, scanning the modulated laser beam across an output medium to form an image of the artwork on the output medium, monitoring the position of the beam and providing a reference signal corresponding to the position of the beam on the output medium, synchronizing the modulation of the beam in accordance with the reference signal, and shifting the phase of the reference signal forward in time to compensate for any delay between the generation of the reference signal and the arrival of the modulated beam on the output medium.

Claim 4

In a method utilizing a laser beam to produce artwork for printed circuit boards, the steps of: providing data signals defining the artwork to be produced, modulating the laser beam in accordance with the data signals, scanning the modulated laser beam across an output medium to form an image of the artwork on the output medium, monitoring the position of the beam and providing a reference signal corresponding to the position of the beam on the output medium, synchronizing the modulation of the beam in accordance with the reference signal, and shifting the phase of the reference signal forward in time to compensate for any delay between the generation of the reference signal and the arrival of the modulated beam on the output medium.

Claim 5

In a system for producing an image on an output medium: a source of data defining the image, means for providing a writing beam of coherent radiation, means for modulating the writing beam in accordance with data signals appled thereto, means for providing a reference beam, a reference mask having alternately arrayed transparent and opaque areas, means for simultaneously scanning the writing beam across the output medium and the reference beam across the reference mask, means responsive to reference beam energy transmitted by the reference mask for providing a reference signal corresponding to the position of the writing beam on the output medium, means responsive to the reference signal for controlling the delivery of data from the data source to the modulating means to provide synchronization between the modulation of the writing beam and the position of said beam in the output medium, and means for shifting the phase of the reference signal forward in time to compensate for signal transmission delays in the system so that the data is delivered when the writing beam is exactly in the position indicated by the reference signal.

Claim 6

In a system for producing an image on an output medium: a source of data defining the image, means for providing a writing beam of coherent radiation, means for modulating the writing beam in accordance with data signals appled thereto, means for providing a reference beam, a reference mask having alternately arrayed transparent and opaque areas, means for simultaneously scanning the writing beam across the output medium and the reference beam across the reference mask, means responsive to reference beam energy transmitted by the reference mask for providing a reference signal corresponding to the position of the writing beam on the output medium, means responsive to the reference signal for controlling the delivery of data from the data source to the modulating means to provide synchronization between the modulation of the writing beam and the position of said beam in the output medium, and means for shifting the phase of the reference signal forward in time to compensate for signal transmission delays in the system so that the data is delivered when the writing beam is exactly in the position indicated by the reference signal.

Claim 7

In a system for producing an image on an output medium: a source of data defining the image, means for providing a writing beam of coherent radiation, means for modulating the writing beam in accordance with data signals applied thereto, means for providing a reference beam, a reference mask having alternately arrayed transparent and opaque areas, means for simultaneously scanning the writing beam across the output medium and the reference beam across the reference mask, means responsive to reference beam energy transmitted by the reference mask for providing a reference signal corresponding to the position of the writing beam on the output medium, means responsive to the reference signal for controlling the delivery of data from the data source to the modulating means to provide synchronization between the modulation of the writing beam and the position of said beam in the output medium, and means for shifting the phase of the reference signal to compensate for delays in the system so that the data is delivered when the writing beam is exactly in the position indicated by the reference signal, said means for shifting the phase of the reference signal including a phase locked loop incorporating a delay therein to effect a forward shift in the reference signal phase such that that signal appears to occur prior to the arrival of the beam at the point where the signal is generated.

Claim 8

In a system for producing an image on an output medium: a source of data defining the image, means for providing a writing beam of coherent radiation, means for modulating the writing beam in accordance with data signals applied thereto, means for providing a reference beam, a reference mask having alternately arrayed transparent and opaque areas, means for simultaneously scanning the writing beam across the output medium and the reference beam across the reference mask, means responsive to reference beam energy transmitted by the reference mask for providing a reference signal corresponding to the position of the writing beam on the output medium, means responsive to the reference signal for controlling the delivery of data from the data source to the modulating means to provide synchronization between the modulation of the writing beam and the position of said beam in the output medium, and means for shifting the phase of the reference signal to compensate for delays in the system so that the data is delivered when the writing beam is exactly in the position indicated by the reference signal, said means for shifting the phase of the reference signal including a phase locked loop incorporating a delay therein to effect a forward shift in the reference signal phase such that that signal appears to occur prior to the arrival of the beam at the point where the signal is generated.