A beam homogenizer for laser annealing (500), for use in a laser annealing apparatus having a laser (100) for producing a laser beam, includes a plurality of cylindrical lenses (510) which have a same radius of curvature and same dimensions in a plane of curvature. The cylindrical lenses (510) have different lengths in a direction of transmission of the laser beam, and any two adjacent ones of the cylindrical lenses have a length difference, in the direction of transmission of the laser beam, greater than a coherence length of the laser (100). Replacement of a combination of transparent glass plates (11) and cylindrical lenses (21) in the prior art with the differently long, larger cylindrical lenses can still achieve de-coherence and homogenization of the laser beam. Diffraction that is detrimental to the homogenization effect can be circumvented, and the complexity and cost of constructing the optical system can be reduced.
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