| 摘要 |
PURPOSE:To sufficiently shorten optical path length to make the whole of a device compact by setting specific conditions in a lens optical system arranged between a light source and a face to be irradiated. CONSTITUTION:The illuminance at an irradiation height H on an irradiated face P is prescribed as S(H), and relation between the irradiation height H and an angle theta which the light beam going to an incidence face F1 of a lens optical system L from a light source LS forms to a lens optical axis Z is prescribed by a formula I to prescribe an angle alpha1, which the incidence face F1 at an incidence height R1 of the lens optical system L forms to the lens optical axis Z, and an angle alpha2, which an exit face F2 at exit height R2 of the lens optical system L forms to the lens optical axis Z, by formulas II and III respectively. In formulas I, II, and III, (n) is the refractive index of the lens and J(theta) is the intensity of radiation in the direction of the angle theta and theta1 is the angle, which the light beam going to the exit face F2 forms to the lens optical axis Z, and phi is the angle which the light beam going from the exit height R2 to the irradiation height H forms to the lens optical axis Z. Thus, the optical path length from the light source to the irradiated face is sufficiently shortened to miniaturize an exposure device.
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