ASSISTANT LIGHT SOURCE AND FRONT-LIGHT

摘要

To provide an assistant light source and a front-light emitting light to the light guide plate efficiently. A sectional shape of prism 14a in the center of light stick is isosceles triangle having a tip angle (T°) of 100° and a tilt angle (a1) of 40°. The depth of the prism 14a is D1µm. A sectional shape of prism 14b in a 1/4 position from an end of light stick is triangle having a tip angle (T°) of 100° and a tilt angle (a2) of 34.8°. The depth of the prism 14b is D2µm. A sectional shape of prism 14c in an end of light stick is triangle having a tip angle (T°) of 100° and a tilt angle (a3) of 24.05°. The depth of the prism 14c is D3µm.