Patent ID: 6563609
Filing Date: 2003-05-13
Classification: G02B,H04N

Abstract:
A linear illuminator for linearly irradiating light flux from a light source onto a surface of an original by a pillar-shaped light guide member formed of a light translucent member, the light source secured to the end face of the light guide member which corresponds to the bottom surface of the pillar body, and the light guide member comprises:a focusing lens unit having a light flux emission face at the position corresponding to the side surface of said pillar shape; a light guide which is continuously formed at the focusing lens unit; and a diffusion and reflection unit provided at the confronting side to the light flux emitting face through the light guide unit, wherein the light flux emission face of the focusing lens unit serves as a non-cylindrical face to set the diffusion and reflection unit and the surface of the original in a conjugate positional relationship with each other, wherein the locus of the light flux emission face on a section parallel to the end face of said light guide member is expressed by the following equation: n(y2+(l0âˆ’z)2)Â½+(y2+(l1+z)2)Â½=nl0+l1 where l0 represents the length on a z-axis from a face top to the diffusion and reflection unit, l1 represents the length on the z-axis from the face top to the surface of the original and n represents a refractive index of the light guide member to air in a coordinate system in which the surface top of the light flux emission face is set to the origin of the coordinate system, the optical axis is set to the z-axis and an axis vertical to an optical axis is set to a y-axis.