| 摘要 |
PROBLEM TO BE SOLVED: To reduce generation of aberration (generation of a blur) and to enable super high-density and super integration to be contrived, in a beam optics system for an optical head such as a beam splitter and a half mirror for an optical head. SOLUTION: In a beam optics member for an optical head for the purpose of dividing an incident light in a prescribed wavelength range into transmitted light and reflected light, a converging optical system like a collimator lens and the like is omitted while a dielectric multilayer film is installed that suppresses, within a specific range, a change in the phase deviation of the transmitted light and reflected light relative to a change in the incident angle of the incident light. In addition, there is provided a dielectric multilayer film that suppresses, within a specific range, a change in the phase deviation of an existing light and a change in the split ratio of a light quantity relative to the change in the incident angle of the incident light. |
