Patent ID: 7508492

Claim:
A surface light source control apparatus for a direct exposure apparatus in which light produced by a surface light source constructed from a plurality of point light sources is directed to a projection device for generating an exposure pattern, and the light reflected by said projection device is projected onto an exposure surface of an exposure target moving relative to said projection device, thereby forming a desired exposure pattern on said exposure surface, said surface light source control apparatus comprising: light-emission level determining means for determining the light-emission level of each of said point light sources for each of a plurality of groups so that a uniform illuminance distribution is achieved at a position corresponding to said exposure surface of said exposure target when said projection device is set so as to reflect all light rays incident thereon toward said exposure surface, said plurality of groups being formed in advance by grouping said point light sources based on similarity in tendency in terms of illuminance distribution characteristics that said point light sources have at said position corresponding to said exposure surface.