GLASS MATERIAL FOR PRESS MOLDING, METHOD FOR MANUFACTURING OPTICAL GLASS ELEMENT EMPLOYING SAME, AND OPTICAL GLASS ELEMENT

摘要

Disclosed is a glass material for press forming providing an optical element having a sufficient optical performance without surface cracks, cloudiness, scratches, and the like even when the glass material contains an easily reducible component. Also disclosed are an optical element having a sufficient optical performance without surface cracks, cloudiness, scratches, and the like and a method for manufacturing the same. Specifically disclosed are a glass material for press forming and a glass optical element each of which comprises a core portion composed of multiple component optical glass and a composite surface layer covering at least a region serving as an optical functional surface of the core portion. The core portion is composed of optical glass that contains an easily reducible component and does not contain Pb. The composite surface layer includes a first surface layer that covers the core portion and a second surface layer that covers the first surface layer. The first surface layer is composed of a component that does not react with the glass of the core portion at the press forming temperature and does not diffuse in the glass of the core portion. The second surface layer is composed of a component that improves formability during the press forming. Also specifically disclosed is a method for manufacturing the optical element.