发明名称 |
Optical device and method of producing the same |
摘要 |
An optical device having a sub-wavelength grating formed in a specified region is disclosed that is able to prevent wave front degradation accompanying a phase difference of a polarized light beam passing through the optical device. The optical device includes a circular-belt-like region where the sub-wavelength diffraction grating is formed, and a center portion where the sub-wavelength diffraction grating is not formed. A vertically polarized light beam used for operations on a blue-light optical recording medium A has a phase difference in the sub-wavelength diffraction grating to be an integral multiple of 2&pgr; and hence is transmitted through the sub-wavelength diffraction grating. A horizontally polarized light beam used for operations on a blue-light optical recording medium is diffracted by the sub-wavelength diffraction grating. The light path length L1 of the light beam passing through the circular-belt-like region is the same as that of the light beam passing through the center portion without the sub-wavelength grating. |
申请公布号 |
US8178010(B2) |
申请公布日期 |
2012.05.15 |
申请号 |
US20100712308 |
申请日期 |
2010.02.25 |
申请人 |
HIRAI HIDEAKI;UMEKI KAZUHIRO;RICOH COMPANY, LTD.;RICOH OPTICAL INDUSTRIES CO., LTD. |
发明人 |
HIRAI HIDEAKI;UMEKI KAZUHIRO |
分类号 |
B29D11/00;G02B5/18;G02B6/34;G11B7/135;G11B7/22 |
主分类号 |
B29D11/00 |
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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