Patent ID: 8599447

Claim:
An illuminating apparatus comprising a light source in which a plurality of light-emitting elements are arrayed, each light-emitting element irradiating light toward a light-irradiated region onto an original, the light-irradiated region extending in a predetermined first direction, wherein, when P is a light-emitting element pitch [mm] in the first direction of the plurality of light-emitting elements, and H is an optical axis distance [mm] between the plurality of light-emitting elements and the original, and when, in an illuminance cycle representing repetition of bright and dark areas in the first direction on a light-irradiated face of the original caused by the plurality of light-emitting elements, M is an unevenness [%] (=(L 1 −L 2 )/L 3 )[%]) obtained by dividing a value, obtained by subtracting a minimum illuminance value (L 2 ) from a maximum illuminance value (L 1 ), by an average illuminance value (L 3 ), and N is an inter-unevenness distance [mm] which is a half cycle of the illuminance cycle, the unevenness [%] (M) and the inter-unevenness distance [mm] (N) satisfy the relation M ≦N/2− 5.5, and the light-emitting element pitch (P) and the optical axis distance (H) satisfy the relation P/H≦0.83.