| 摘要 |
PURPOSE:To enable any surface of a molded resin body to be marked with high bond strength, by a method wherein a marking substance having the same color as that of a raw material resin and showing a color change when being heated is mixed in the resin, and the surface of a molded body obtained by molding the resin is selectively irradiated with laser beams to change the color of the marking substance. CONSTITUTION:An appropriate quantity of 2PbCO3.Pb(OH)2 is mixed into a polyphenylene oxide resin (Noryl resin), white reflective plate 1 is moded from the mixture, and the plate 1 is used to manufacture a light-emitting display device. The reflective plate is molded at 300-320 deg.C, and since the color change temperature of 2PbCO3.Pb(OH)2 is higher than the molding temperature, the plate 1 remains white in color, and its reflecting effect is not deteriorated. Next, a side surface of the plate 1 is selectively irradiated with a laser beam by scanning the beam imagewise. By this, 2PbCO3.Pb(OH)2 contained at the irradiated part is turned yellowish orange by the laser heating, resulting in marking in yellowish orange against the white ground. Accordingly, a mark 4'' is provided on the side surface of the reflective plate 1. |
