Double-side display device with surface light source device having deflection patterns

摘要

A double-side LCD having a surface light source device including a light guide plate and a light source facing one end face of the light guide plate. A plurality of deflection patterns are formed in a surface facing a light outgoing plane of the light guide plate, the deflection pattern includes an inclined plane facing the light source side and a re-incident plane substantially perpendicular to the light outgoing plane. Light from the light source is reflected by the inclined plane and outputted from the light outgoing plane to the LCD. A tilt angle (alpha) of the inclined plane satisfies: 45°-[Sin^-1(Sin theta/n)]/2<=alpha<=45°+[SIN^-1(Sin theta/n)]/2, wherein theta is an angle between a direction of peak brightness of outputted light and a direction perpendicular to the light outgoing plane, n is a refractive index of the light guide plate, and theta is within 6-15°.