| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain uniformity of emission luminosity by suppressing abnormal light emission near an incident surface of a light guide plate, even if an LED is used as a light source. <P>SOLUTION: LEDs 5 are arranged so as to face an incident surface 4 of a light guide plate 3, light emitted from the LEDs 5 is propagated through an inside of the light guide plate 3 after the light is incident inside the light guide plate 3 from the incident surface 4 of the light guide plate 3, and when the incident angle to an emission surface 6 in this propagation process is a critical angle or less, the light is emitted from the emission surface 6 of the light guide plate 3. On at least either the emission surface 6 of the light guide plate 3 or a surface 10 opposite to that, a large number of prism protrusions 12 extending toward a direction further away from the vicinity of the incident face 4 are formed in parallel along the incident surface 4. And also, side-face side portions 10b of the prism protrusions 12 are formed so as to have a height gradually tending to decrease as a distance from the incident surface 4 decreases, as well as, a top part shape and a groove shape of the prism protrusions 12 or its top part shape are formed in a cross-section nearly arc shape. <P>COPYRIGHT: (C)2008,JPO&INPIT |
