| 摘要 |
PROBLEM TO BE SOLVED: To always uniformly irradiate the whole information recording symbol with the fixed quantity of light by applying light diffusing treatment by surface- roughening method to the irradiation face of a transparent body. SOLUTION: An illuminator 17 is constituted of an outer wall 50 erected like surrounding the upper peripheral part of a transmission window 41, an upper panel 51 mounted on the outer wall 50 and an upper plate 51 integrally fitting a cover glass to the position of the upper face of the transmission window 41, and the transparent body 52 fixed to the lower face of the upper panel 51 and inserted to the outer wall 55. This transparent body 52 is formed from transmissive glass or resin and is provided with a through hole 53 for looking into a data symbol 4 at the center. Then the inner peripheral surface of the through hole 53 is a diffusing face 55 as an irradiating face, this diffusing face 55 is made to face down, namely a taper surface extending its lower side, and its, surface is subjected to surface-roughening work so as to uniformly diffuse irradiating light. |
