| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain an original lighting system which is improved in lighting efficiency and set uniform in illuminance both in a main scanning direction and in an auxiliary scanning direction by using a light guide board of comparatively simple configuration. <P>SOLUTION: A polygonal light guide plate 2, which is inscribed (partial coincidence is included) on a rectangle 20 having a length/width ratio (it is called a squareness ratio) of 1 or more to 1 in a cross-sectional shape, is arranged so as to set its optical axis L0 at a prescribed angle with the surface 5 of an original. Side faces c1, c3, and c6 serve as reflecting surfaces. An LED 1 is set very close to the plane of incidence 2a of the light guide plate 2, the high illuminance part of a composite curve G obtained from the distributions of illuminance of direct light and reflected light from the reflecting surfaces is considered as a maximum reading width B on the surface of the original, and a reading region is set in the maximum reading width B. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
