| 摘要 |
An objective lens of an optical pickup apparatus converges a divergent light flux onto an information recording surface. The following conditional formula is satisfied: | delta SA1/ delta U|•| delta U| + | delta SA2/ delta T|•| delta T| </= 0.07 lambda rms where lambda represents a wavelength of a light source, delta SA1/ delta U represents a change of a spherical aberration for an object-to-image distance change delta U (| delta U| </= 0.05 mm) and delta SA2/ delta T represents a change of spherical aberration for a temperature change delta T (| delta T| </= 30 DEG C), the object-to-image distance is a distance between the light source (a light emitting point) and the information recording surface. |
