摘要 |
A light irradiation apparatus irradiates a target plane with light having a predetermined light intensity distribution. The apparatus includes a light modulation element having a light modulation pattern of a periodic structure represented by a primitive translation vector (a1, a2), an illumination system for illuminating the modulation element with the light, and an image forming optical system for forming the predetermined light intensity distribution obtained by the modulation pattern on the target plane. A shape of an exit pupil of the illumination system is similar to the Wigner-Seitz cell of a primitive reciprocal lattice vector (b1, b2) obtained from the primitive translation vector (a1, a2) by the following equations: b1=2&pgr;(a2×a3)/(a1·(a2×a3)) and b2=2&pgr;(a3×a1)/(a1·(a2×a3)) in which a3 is a vector having an arbitrary size in a normal direction of a flat surface of the modulation pattern of the modulation element, “·” is an inner product of the vector, and “×” is an outer product of the vector.
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