Patent ID: 8647464

Claim:
A method for manufacturing a resin molding, the method comprising: providing a light-transmitting resin member having a loop-shaped protruding portion formed on a rear surface of the light-transmitting resin member and having a loop-shaped end surface, the protruding portion having inner and outer side surfaces each configured with an asymmetric inclination angle with respect to a normal of the end surface of the protruding portion; pressing the loop-shaped end surface of the protruding portion that is a loop-shaped welded region of the light-transmitting resin member, and a loop-shaped welded region of a corresponding light-absorbing resin member, together so that the loop-shaped welded regions are opposed to each other, and then causing a laser beam emitted from a laser light source to be incident on a surface of the light-transmitting resin member while the laser beam is refracted, the laser light source being positioned above and inside the loop-shaped welded regions; and repeatedly irradiating the laser beam onto the loop-shaped welded regions to heat and fuse the entire loop-shaped welded regions to weld the light-transmitting resin member and the light-absorbing resin member while opposed to each other and pressed together, wherein the inclination angle of the inner side surface of the protruding member near the laser light source is equal to or more than a travel angle of the refracted laser beam and is over 0° and equal to or less than 40° so that an optical path within the light-transmitting member through which the laser light travels is not hindered and the entire loop-shaped welded regions are irradiated with the laser light without a shadow, and wherein repeatedly irradiating the laser beam includes scanning the laser beam using a Galvano scanner so that a laser beam irradiation is received multiple times at the loop-shaped welded regions of the light-transmitting resin member and the light-absorbing resin member until they reach the softening temperature thereof from temperatures before irradiation and a further laser beam irradiation is received multiple times at the loop-shaped welded regions of the light-transmitting resin member and the light-absorbing member until they reach a fused state, thereby heating the entire loop-shaped welded regions substantially uniformly at substantially the same time.