LIGHT GUIDE AND IMAGE READER

摘要

[PROBLEMS] To provide a light guide in which unevenness in color does not take place even at a part close to the incident face. [MEANS FOR SOLVING PROBLEMS] A rod-like light guide (3) is produced by injection molding transparent resin such as acryl, and its surface comprises an exit face (3a), a bottom face (3b), right and left side faces (3d, 3c) and end faces (3e, 3f). One end face (3e) opposes a light emitting unit (10), and a light scattering pattern for scattering incident light from the end face (3e) is formed on the bottom face (3b). The light scattering pattern provides pattern shapes different between a portion close to the end face (3e) as the incident face and a portion separated from the end face (3e). The light scattering pattern (11) formed at the portion close to the incident face consists of a large number of fine hemispherical recesses whereas the light scattering pattern (12) separated from the incident face consists of triangular grooves or half-cut tubular grooves, and the axial direction of these triangular grooves or half-cut tubular grooves is the width direction (sub-scanning direction) of the pattern-forming bottom face (3b).