发明名称 |
DIFFRACTION GRATING, ABERRATION CORRECTION ELEMENT AND OPTICAL HEAD DEVICE |
摘要 |
There is provided a diffraction grating including a convex portion and a concave portion which are used for lights having different wavelengths λ1, λ2 and λ3 and are alternately disposed on at least one surface of a substrate with a predetermined pitch. An average refractive index of the convex portion is smaller than an average refractive index of the concave portion. A phase difference in the lights having the wavelength λ1 which transmit the convex portion and the concave portion and a phase difference in the lights having the wavelength λ2 which transmit the convex portion and the concave portion are both substantially the integral multiple of 2&pgr;, and a phase difference in the lights having the wavelength λ3 which transmit the convex portion and the concave portion is substantially the non-integral multiple of 2&pgr;. |
申请公布号 |
US2012287767(A1) |
申请公布日期 |
2012.11.15 |
申请号 |
US201213556507 |
申请日期 |
2012.07.24 |
申请人 |
MIYASAKA KOJI;SATO HIROMASA;ASAHI GLASS COMPANY, LIMITED |
发明人 |
MIYASAKA KOJI;SATO HIROMASA |
分类号 |
G11B7/135 |
主分类号 |
G11B7/135 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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