| 摘要 |
PROBLEM TO BE SOLVED: To obtain such a back light that prevents irregular distribution of illuminance at a low cost but gives enough illuminance and can prevent irregular distribution of illuminance even when the number of light sources is increased, by disposing a specified shielding plate to obtain uniform illuminance of light from a light source. SOLUTION: A shielding plate 3 composed of a transparent or translucent plastic material such as a transparent polyester film is disposed on the upper side of a box case 4. A slit pattern is printed on the shielding plate 3 by using a white ink essentially composed of titanium oxide so that the slits are parallel to the longitudinal direction of a light source (fluorescent light) 5. A light scattering plate 2 is disposed on the shielding plate 3, and a liquid crystal display element 1 is disposed thereon. The slit pattern printed on the shielding plate 3 is formed in such a manner that the pattern is dense near the light source 5 and rough as distanct from the light source 5. The printed pattern on the shielding plate 3 may be another pattern as far as it shows a dense and rough pattern in which proportion of the light-shielding part increases near the light source, and a dot or lattice pattern can be used. |
