Patent ID: 7360953
Filing Date: 2008-04-22
Classification: G02B

Abstract:
1. A light guiding device used for exposure of peripheral parts of a semiconductor wafer, comprising: an optical fiber bundle, formed by bundling together a plurality of optical fibers and having a first light incidence end face and a first light emitting end face; a glass rod, having a second light incidence end face and a second light emitting end face and making uniform the cross section of light emitting from said second light emitting end face by taking in, at said second light incidence end face, the light having emitted from said first light emitting end face of the optical fiber bundle and guiding this light to said second light emitting end face; and a glass rod holding member, which fixes said glass rod to a light emitting end face side front end part of said optical fiber bundle so that said second light incidence end face of the glass rod faces said first light emitting end face of the optical fiber bundle, said second light emitting end face of the glass rod having a rectangular shape, wherein said glass rod satisfies the relationships expressed by the following formulae (1) and (2): where: L[mm]: length of said glass rod d[mm]: length of the diagonal of said second light emitting end face of the glass rod n: refractive index of air n′: refractive index of said glass rod θ: maximum emit angle from said optical fiber into air θ′: angle of refraction of light, which has emitted from said optical fiber at the maximum emit angle, upon incidence onto said second light incidence end face.