The utility model provides a
laser irradiation system and a
laser processing system, which can restrain the influence of deflection caused by the
dead weight of a
mask so as to carry out
laser irradiation with high precision, and also can restrain dust from being attached to the surface of the
mask, so that badness caused by the dust is difficult to generate, and the height is low. The laser
irradiation system comprises a first optical function part and a second optical function part, the first optical function part comprises a
laser light source, and the second optical function part is used for arranging a
mask with a pattern corresponding to a laser irradiation area of an irradiated body. The laser irradiation system is used for irradiating
laser light to an irradiated body through a mask arranged on a second optical function part, and the mask is a
quadrilateral mask which comprises an effective area with a pattern corresponding to a laser irradiation area of the irradiated body, and the length of the longest side of four sides, namely the outer edge of the mask, is more than 800mm. In the second optical function part, the normal line of the surface on which the pattern is formed faces the substantially horizontal direction.