Manufacturing method for optical head device and optical head device

1. A manufacturing method for an optical head device including a plurality of light sources emitting light beams with different wavelengths, a plurality of diffraction elements generating a main beam and sub-beams from the respective light beams emitted from the plurality of light sources, a common light receiving element receiving a reflected light beam from an optical recording medium, and a device frame on which the plurality of light sources, the plurality of diffraction elements, the light receiving element and an objective lens drive mechanism are mounted, comprising the steps of:

integrating at least the plurality of light sources and the plurality of diffraction elements with each other as an optical module;

adjusting a relative positional relationship between the plurality of diffraction elements with each other on the optical module;

then, adjusting spot positions of the sub-beams on the optical recording medium by adjusting the entire optical module on the device frame; and

after that, fixing the optical module on the device frame.

2. The manufacturing method for an optical head device according to claim 1 , wherein the adjustment of the relative positional relationship of the plurality of diffraction elements is performed by observing images of the diffracted sub-beams generated by the plurality of diffraction elements on the optical module.

3. The manufacturing method for an optical head device according to claim 1 , wherein the adjustment of the relative positional relationship of the plurality of diffraction elements is performed by observing grating patterns formed on the plurality of diffraction elements.

4. The manufacturing method for an optical head device according to claim 1 , further comprising the steps of:

providing in a mounting part for the diffraction element a positioning part for the diffraction element in a direction of an optical axis, a spring member urging the diffraction element against the positioning part for temporarily fixing the diffraction element, and a projection serving as a supporting point when the diffraction element is swung in a circumferential direction of the optical axis or an axial line parallel to the optical axis;

adjusting the relative positional relationship between the plurality of diffraction elements on the optical module; and then

fixing the diffraction elements on the optical module.

5. An optical head device comprising:

a plurality of light sources emitting light beams with different wavelengths;

a plurality of diffraction elements generating a main beam and sub-beams from the respective light beams emitted from the plurality of light sources;

a common light receiving element receiving a reflected light beam from an optical recording medium; and

a device frame on which the plurality of light sources, the plurality of diffraction elements, the light receiving element and an objective lens drive mechanism are mounted;

wherein at least the plurality of light sources and the plurality of diffraction elements are mounted on the device frame in a state that the plurality of light sources and the plurality of diffraction elements are integrated with each other as an optical module, and at least one of respective mounting parts of the optical module for the plurality of diffraction elements is provided with a positioning part for the diffraction element in a direction of an optical axis, a spring member urging the diffraction element against the positioning part for temporarily fixing the diffraction element, and a projection serving as a supporting point when the diffraction element is swung in a circumferential direction of the optical axis or an axial line parallel to the optical axis.