Scanner system having a dual trace spinner

A scanning optical system receiving a substantially circularly polarized optical beam, said system comprising:

• a modulator means for providing modulation to said circularly polarized optical beam in response to received modulator control signals;
• a curved platen for receiving a substrate;
• a raster scanning means responsive to advancement control signals for advancing, relative to said substrate, an optical beam across a substrate surface in a first direction forming a scan line and for cooperatively advancing, relative to said substrate surface, said circularly polarized optical beam in a second direction substantially perpendicular to said first direction;
• a means for generating first and second optical scan beams respectively polarized in first and second polarization directions in response to polarization control signals;
• an encoder means for generating encoder signals indicative of the angular position of a spinner about a scan axis and consequently indicative of the optical beam along a current scan line;
• a controller, receiving said encoder signals, for generating said advancement control signals and said modulator control signals, said controller further providing said optical beam polarization switching signals in dependence on said encoder signals such that said optical beam polarization is switched between said first and second polarization direction after the completion of the current scan line;
• said spinner receiving said first and second optical scan beams and including
• a first quarter wave plate, receiving said optical beam, for providing linearly polarized first and second scan beams;
• a polarization sensitive beamsplitter for presenting each of said first and second linearly polarized scan beams respectively along a one of two scan beam output axes displaced from each other and selected in dependence upon said scan beam polarization;
• a focusing means for receiving and focusing said beamsplitter output beams along substantially parallel axes onto said substrate surface;
• and
• an optical deflection means for presenting said first and second linearly polarized scan beams in opposed directions, thereby generating two scan beams per beam splitter revolution about said scan axis.