Patent ID: 8406091

Claim:
A thermally-assisted magnetic recording head in which a slider including an optical system configured to propagate light for thermal assist and provided in an element-integration surface of a slider substrate is joined with a light source unit, the light source unit comprising: a unit substrate including: a joining surface which faces the slider substrate when the light source unit is joined with the slider; and a source-installation surface adjacent to the joining surface; a light source having a light-emission center and a rear light-emission center on a side opposite to the light-emission center, which is provided on the source-installation surface and emits light for thermal assist to be entered into the optical system from the light emission center; and a photodetector section, being a semiconductor photodiode structure formed of a portion of the unit substrate and being included within the unit substrate, configured to measure an output from the light source based on light emitted from the rear light-emission center, a light-receiving portion of the photodetector section being located in the source-installation surface of the unit substrate and directly facing the rear light-emission center of the light source to receive the light emitted from the rear light-emission center, a back surface of the slider substrate on a side opposite to an opposed-to-medium surface being joined to the joining surface of the unit substrate so that the light emitted from the light-emission center directly enters the optical system.