Patent ID: 7540646

Claim:
A light guide element for being arranged between a light source and a light guide plate and for guiding a light flux from the light source into the light guide plate, the light guide element comprising: an incident surface for receiving an incident light flux from the light source; an emitting surface for emitting a light flux to the light guide plate; a top surface and a base surface both extending in a direction to intersect with the incident surface and the emitting surface and facing each other, wherein one of the top surface and the base surface inclines to the other so that a dimension of the emitting surface along a thickness of the light guide plate becomes smaller than a dimension of the incident surface along the thickness of the light guide plate; and a structure in a light leakage reducing shape including a plurality of reflection surfaces arranged on at least one of the top surface and the base surface, wherein when an incident light flux emitted from the light source travels along a plane extending in a direction from the incident surface to the emitting surface and further extending along the thickness of the light guide plate, the plurality of reflection surfaces provide the light flux traveling along the plane with a direction component so as to deflect away from the plane.