| 摘要 |
PROBLEM TO BE SOLVED: To provide a highly accurate high resolution exposure head by realizing a high extinction ratio. SOLUTION: The exposure head is designed such that the ratioλ/Λbetween the wavelengthλof a laser light and the size of the diffraction grating of a GLV per period and each parameter satisfy a relation (A). Since a zero order light and±first order lights are separated perfectly from each other, extinction ratio is enhanced. In the relation (A),λis the wavelength of the laser light,Λis the size (lattice pitch) of the diffraction grating of the GLV per period,θis the angle of a beam exiting an illumination light source derived from the number of aperture (NA) of an optical fiber, n is the number of the optical fibers, d is the diameter of the clad of the optical fiber, W is the beam width at the position arranged with the GLV (irradiation face), and (a) is the size of one pixel on the GLV. COPYRIGHT: (C)2004,JPO
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