Patent ID: 8040332

Claim:
A light scan device which forces a beam light to scan depending on an image signal, comprising: a light source part for supplying the beam light; and a scanning part for forcing the beam light from the light source part to scan an illumination-target region in a first direction and a second direction substantially orthogonal to the first direction, wherein the scanning part is driven so that a frequency with which the beam light is forced to scan in the first direction is higher than a frequency with which the beam light is forced to scan in the second direction, a spot formed on a pixel of the illumination-target region by the beam light has a form with a shorter size in the first direction than in the second direction, a length of the spot in the second direction is substantially equal to a length of a pixel formed according to the image signal in the second direction, and the length of the spot in the first direction is less than the length of the pixel formed according to the image signal in the first direction, and the light source part is driven so as to turn on the beam light with respect to a pixel depending on the image signal at a timing when an outer edge of the spot goes over a boundary of the pixel subsequently to a center position of the spot and turn off the beam light at a timing when the outer edge of the spot reaches another boundary of the pixel after turning on the beam light, provided that the outer edge of the spot is a line at which an intensity of the beam light is attenuated to predetermined intensity which is half of a peak intensity of the spot.