| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a means of suppressing generation of diffracted light caused by a concavo-convex in the front light having a fine concavo-convex for preventing reflection on the light emitting face of a light guide plate. <P>SOLUTION: The front light comprises a light source and a light guide plate which introduces the light from the light source and emits the light from a light emitting face located on the opposite side to the surface on observation side. A reflection preventive pattern consisting of a fine concavo-convex 30 for reflection prevention is formed at the light emitting face. When the wavelength of the visible light having the shortest wavelength out of the light emitted from the light source 24 is made λmin, the refractive index of the light guide plate, n1, and the refractive index of the air, n0, the period p of the fine concavo-convex 30 satisfies the following formula, p<λmin/(n0+n1). Thereby, emission of diffracted light from the reflection preventative pattern (light emitting face) of the light guide plate can be prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
