Mounting method for optical device and optical head equipment

An optical head device comprising:

• a light source for irradiating a disk substrate with light to conduct at least one of writing and reading of information;
• and
• a driving circuit for driving the light source to output light,
• wherein the light source is mounted by a mounting method including the steps:
• preparing a substrate in which at least a first electrode and a second electrode are disposed and an optical device in which a third electrode and a fourth electrode are disposed corresponding to the first electrode and the second electrode respectively, in which
• surfaces for mounting the third electrode and the fourth electrode of the optical device have a first height (ah1) and a second height (ah2) from one surface of the optical device on the side opposite to the surface for mounting the third electrode and the fourth electrode, respectively, where ah1>ah2,
• each of the first electrode and the second electrode has at least a solder-underlying region and solder on the solder-underlying region, and
• letting the solder-underlying region area of the first electrode is aS1, the solder-underlying region area of the second electrode is aS2, the third electrode area is aS3, the fourth electrode area is aS4, the volume of a solder disposed on the solder-underlying region of the first electrode is v1, and the volume of a solder disposed on the solder-underlying region of the second electrode is v2, v1≠v2, and
• each of the values of ah1, v1, aS1, ah2, v2 and aS2 is set so that the height of the first electrode and the second electrode from the surface of the solder-underlying region to the opposing surface of the optical device is a height in proportion with ah1+v1/aS1 or ah2+v2/aS2 after melting of the solder, and
• positioning the substrate and the optical device so that the third electrode of the optical device is disposed on the first electrode of the substrate and the fourth electrode of the optical device is disposed on the second electrode of the substrate, melting the solder and soldering the semiconductor element to the substrate.