OPTICAL DEVICE, OPTICAL RECORDING HEAD AND OPTICAL RECORDING DEVICE

摘要

Provided is an optical device configured to makes it possible to enhance use efficiency of light.  An optical device is provided with an optical element to deflect incident light and a fixation member on which the optical element is fixed.  The optical element includes a reflective surface and a diffraction grating surface that deflects the incident light.  The optical element is fixed on the fixation member to restrain displacement in accordance with temperature changes at portions thereof other than the reflective surface and the diffracting grating surface in such a condition that displacement is caused without restraint by temperature changes at the reflective surface and the diffraction grating surface.  A change of the incident light in the deflection angle due to an inclination change by the reflective surface and the diffracting grating surface is suppressed by a change in a diffraction angle due to a periodical change in the diffraction grating by the displacement of the diffracting grating surface.