PLANAR LIGHT SOURCE AND IMAGE DISPLAY

摘要

Light is introduced from a spot light source (42) to a light guide plate (43). A large number of recessed deflection patterns (59) having a triangular cross-section are formed on the surface (pattern surface (61)) of the light guide plate (43) opposite to the light exit surface (60). A prism sheet (44) having a plurality of arcuate prisms (70) formed thereon is disposed at a position facing the pattern surface (61) of the light guide plate (43). A light propagating through the light guide plate (43) exits the light exit surface (60) substantially perpendicularly thereto when it is totally reflected on the deflection patterns (59). The light propagating through the light guide plate (43) and exiting the deflection patterns (59) obliquely is bent to the direction substantially perpendicular to the pattern surface (61) by means of the prisms (70) when it passes through the prism sheet (44). Light utilization efficiency is improved using such a planar light source. Even when it is combined with a transmission type display panel, possibility of passing an external light through the display can be reduced.