| 摘要 |
PURPOSE:To obtain a quality image pickup output easy to binary code, by preventing direct entry of an illumination light passing through a through hole of a printed circuit board into a camera. CONSTITUTION:A lighting unit 20 forms a linear light source as a whole and is arranged parallel with the scanning direction of a lien sensor camera 10. The tip of a light shielding plate 28 sticks out by a proper length from an emission end face 26b of a photoconductive plate 26 and the radial expanse of the emission light from the end face 26b in regulated with the light shielding plate 28. Light from the lighting device 20 exists on the left from a limit line R and little on the right. The tilt angle alpha of the lighting device 20 is almost a half theta as much as the width-wise view angle 2theta of the camera 10 viewed from an object S. Thus, the light from the light unit 20 is prevented from the directly entering the view of the camera 10 even if traveling straight through the through hole 14c. |
