Patent ID: 7309154

Claim:
A light guide plate comprising: a slender first guiding portion which has an end face providing an incidence face and extends along an extending direction vertical to said end face; a guiding-and-emitting-portion having a generally rectangular major face providing an emission face; a plurality of second guiding portions which bridge said first guiding portion to said guiding-and-emitting-portion at a plurality of positions along said extending direction, each of said second guiding portion having a first side face providing an inner-reflection face and a second side face nearer to said end face as compared with the first side face; said first side face being connected to said first guiding portion at a first connection portion and being connected to said guiding-and-emitting-portion at a second connection portion; said second side face being connected to said first guiding portion at a third connection portion and being connected to said guiding-and-emitting-portion at a forth connection portion; said first side face making a first angle smaller than 90° with respect to said extending direction at said first connection portion; an imaginary straight line passing said first connection portion and said second connection being making angle α smaller than 90° with respect to said extending direction; and said second side face making a second angle which is not greater than 90° but greater than angle α with respect to said extending direction at said third connection portion.