| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical glass which has a high refractive index, high dispersiveness, excellent precision press forming property, excellent transmittance, and excellent internal quality and can suppress a transmittance deterioration in aging. SOLUTION: The optical glass is a phosphate optical glass containing Pt of≤1.5 ppm in the glass. When its specimen with a thickness of 10 mm, both faces of which are polished, is irradiated with an ultraviolet and/or visible light at a light receiving energy of≤0.4 mW×cm<SP>-2</SP>for≥200 h, the difference of internal transmittance before and after irradiation (before irradiation-after irradiation) against a light with a wavelength of 420 nm is 0.1 or less in terms of a sample having a thickness of 10 mm. COPYRIGHT: (C)2007,JPO&INPIT
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