Patent ID: 7119875

Claim:
An apparatus for forming a pattern comprising: a light source that emits a beam; a scanning unit that scans the beam on a photosensitive material; a scanning-time setter that sets a fine-section scanning-time as a pass-time of the beam for each section of a series of fine sections, the series of fine sections being defined by dividing a scanning-line into constant-intervals; a time-error detector that successively detects a time-error between the set fine-section scanning-time and an actually detected fine-section scanning-time for each fine section; a scanning-time corrector that successively corrects the set fine-section scanning-time for each fine section on the basis of the time-error, to successively generate a corrected fine-section scanning-time; a pulse data selector that successively selects a set of pulse data, corresponding to the corrected fine-section scanning-time, from a series of sets of pulse data, each of said series of sets of pulse data having a different data-array in accordance with the corrected fine-section scanning-time; a control pulse signal generator that successively generates a sequence of control pulse signals in accordance with the selected set of pulse data; a writing pulse signal generator that successively generates a sequence of writing pulse signals in accordance with the sequence of control pulse signals, the sequence of control pulse signals controlling the output-timing of the sequence of writing pulse signals; and an optical modulator that modulates the beam in accordance with the sequence of writing pulse signals.