Minimization of differential bow in multiple beam scanning optical systems

A raster scanning system comprising:

• two light sources each emitting a light beam along a path;
• a medium;
• scanning means located in the path of the light beams from said two light beams and being so constructed and arranged to scan the light beams in a tangential plane across said medium;
• a first optical means and a second optical means;
• a wobble correction mirror;
• said first optical means located between said scanning means and said second optical means and having a spherical concave surface for receiving the light beams from said scanning means and a cross scan cylindrical convex surface through which the light beams exit;
• said second optical means located between said first optical means and said wobble correction mirror and having a cross scan cylindrical concave surface for receiving the light beams from said first optical means and a spherical convex surface through which the light beams exit;
• said wobble correction mirror located in the path of the light beams from said second optical means and having a cross scan cylindrical concave surface to reflect the light beams onto said medium;
• said second optical means and said wobble correction mirror being so constructed and arranged relative to each other for generating a field curvature to substantially reduce differential bow between the light beams;
• and
• said first optical means, said second optical means and said wobble correction mirror being so constructed and arranged relative to each other to substantially reduce the generated field curvature.

A raster scanning system for reducing the differential bow between two light beams by generating a field curvature comprising:

• two light sources each emitting a light beam along a path;
• a medium;
• scanning means located in the path of the light beams from said two light sources and being so constructed and arranged to scan the light beams in a tangential plane across said medium;
• a first optical means and a second optical means;
• a cross scan cylindrical concave mirror;
• said first optical means located between said scanning means and said second optical means and having a concave surface for receiving the light beams from said scanning means and a cross scan cylindrical convex surface through which the light beams exit;
• said second optical means located between said first optical means and said mirror and having a cross scan cylindrical concave surface for receiving the light beams from said first optical means and a convex surface through which the light beams exit;
• said mirror located in the path of the light beams from said second optical means and having a cross scan cylindrical concave surface to reflect the light beams onto said medium;
• and
• said second optical means and said mirror being so constructed and arranged relative to each other for generating a field curvature to substantially reduce differential bow between the light beams;
• and
• said first optical means, said second optical means and said mirror being so constructed and arranged relative to each other to substantially reduce the generated field curvature.

A raster scanning system for reducing the differential bow between two light beams by generating a field curvature comprising:

• two light sources each emitting a light beam along a path;
• a medium;
• scanning means located in the path of the light beams from said two light sources and being so constructed and arranged to scan the light beams in a tangential plane across said medium;
• a first optical means and a second optical means;
• a cross scan cylindrical concave mirror;
• said first optical means located between said scanning means and said second optical means and having a concave surface for receiving the light beams from said scanning means and a cross scan cylindrical convex surface through which the light beams exit;
• said second optical means located between said first optical means and said mirror and having a cross scan cylindrical concave surface for receiving the light beams from said first optical means and a convex surface through which the light beams exit;
• said mirror located in the path of the light beams from said second optical means and having a cross scan cylindrical concave surface to reflect the light beams onto said medium;
• and
• said first optical means, said second optical means and said mirror being so constructed and arranged relative to each other for substantially reducing differential bow between the light beams by generating and optimizing a field curvature.