Abstract: A light source unit for thermally-assisted magnetic head includes a substrate member having a first bonding surface; a light source assembly attached on the first bonding surface of the substrate member and having a second bonding surface; and a heater circuit assembly formed between the substrate member and the light source assembly, the heater circuit assembly having a heater formed on the substrate member and two leads connected at two ends of the heater, the lead being thicker than the heater, thereby a distance between the heater and the second bonding surface is farther than that between the lead and the second bonding surface. The light source unit can reduce mechanical stress and thermal conduction between a light source assembly and a substrate member, thereby improving the performance of the light source assembly and the heater.

Abstract: A light source-unit which is used for a thermally assisted magnetic head, comprises a laser diode and a sub-mount which the laser diode is joined. The sub-mount comprises a joint-surface which the laser diode is joined and a convex part protruding from the joint-surface. The light source-unit comprises an alloy layer, made of alloy, which is formed between the surface of the convex part and an opposing-surface, of the laser diode, opposing to the joint-surface.

Abstract: A light source unit for thermally-assisted magnetic head includes a substrate member having a bonding surface, multiple layers formed on the bonding surface and comprising a base layer, a connection pad layer, an insulation layer and a bonding layer; a light source assembly attached on the bonding layer of the substrate member and having a laser diode embedded therein and connected to the connection pad layer on the bonding surface, so as to form a laser diode circuit; and a heater buried in the insulation layer and connected to the connection pad layer, so as to form a heater circuit. The light source unit can maintain stable heat power for facilitating performance of the thermally-assisted magnetic head, and further reduce the sizes of the light source unit and substrate member.