US Patent 7336391 Multi-exposure drawing method and apparatus therefor

In a multi-exposure drawing method for drawing a pattern on a drawing surface, using an exposure unit including a plurality of optical modulation elements arranged in a matrix manner, the unit is continuously and relatively moved at a constant velocity with respect to the drawing surface in an array-direction defined by a matrix-arrangement of the modulation elements. Optical modulation elements, spaced at a regular interval in an alignment of optical modulation elements along the array-direction, are successively and selectively driven based on a same bit datum, to thereby modulate a light beam made incident thereon, whenever the exposure unit is moved by a distance corresponding to the regular interval, resulting in the production of a pixel dot on the drawing surface in a multi-exposure manner by the modulated light beams. The exposure time for producing the pixel dot by each of the modulated light beams is shorter than the time required to move the exposure unit by a distance corresponding to the size of one pixel dot.