Patent ID: 6081319
Filing Date: 2000-06-27
Classification: G03F

Abstract:
An illumination system, comprising:light source means for providing pulse light; andscanning means for relatively and scanningly moving an article, to be illuminated, relative to an illumination region to be defined by the pulse light;wherein, in a light intensity distribution defined in the illumination region with respect to a scan direction, the light intensity distribution being substantially in the shape of a trapezoid having a substantially straight top portion with at least one corner of the trapezoid being replaced by a curved line to complete the trapezoidal shape, the light intensity changes non-linearly from at least one end portion to a highest light intensity point in the distribution;wherein the light intensity distribution includes a first point at said one end portion, a second point whereat light intensity increase changes, a third point whereat light intensity increase changes, and a fourth point whereat the light intensity is highest;wherein the curved line to be replaced by a corner of the trapezoidal shape is protruded downwardly between the first and second points while it is protruded upwardly between the third and fourth points; andwherein at least one of a width Wa between the first and second points and a width Wb between the third and fourth points substantially corresponds to or is greater than the relative movement amount between the illumination region and the article per pulse.