Optical imaging head having a multiple writing beam source

摘要

A method for transferring an image to a medium includes: generating a substantially uniform line of radiation; producing diffractive light from the uniform line of radiation; passing zero order diffractive light to the medium in a telecentric fashion while blocking non-zero order diffractive light; adjusting image magnification on the medium independent of image focus in response to the zero order diffractive light; and adjusting image focus on the medium independent of image magnification in response to the zero order magnification-adjusted diffractive light. An optical imaging head for transferring an image onto a medium via the above method includes: a line illumination module for generating a substantially uniform line of radiation; a grating light valve which receives the line of radiation and generates diffractive orders of modulated radiation; a first lens group for adjusting image magnification independent of image focus; a second lens group for passing radiation to the medium in a telecentric fashion, the second lens group adjusting image focus independent of image magnification; and a stop, placed between the first and second lens groups, having a single aperture for passing zero order radiation and blocking non-zero order radiation.