Patent ID: 8580069

Claim:
A method of making integral members for a planar light source device, the method comprising: irradiating one of opposite surfaces of a first member made of a plastic material, that is to be bonded with a second member, with energy rays having quantum energy not lower than 4 eV; and directly bonding the first and second members together at room temperature after the irradiating without any bonding agent being used, wherein respective mating surfaces of the first and the second members are not melted when bonding, wherein: the first member comprises a light guide element for propagating rays of light from a light source towards a light exit surface thereof; and the second member comprises an optical film disposed on the light exit surface of the light guide element; and forming a plurality of projections operable to transmit rays of light from the light exit surface of the light guide element towards a front surface region of the light exit surface, on one of opposite surfaces of the optical film that confronts the light guide element; wherein the light guide element is directly bonded with the optical film at vertexes of the plural projections.