Invention Grant
US07511887B2 Diffraction grating, method of fabricating diffraction optical element, optical pickup device, and optical disk drive
有权
衍射光栅，衍射光学元件的制造方法，光学拾取器件和光盘驱动器
- Patent Title: Diffraction grating, method of fabricating diffraction optical element, optical pickup device, and optical disk drive
- Patent Title (中): 衍射光栅，衍射光学元件的制造方法，光学拾取器件和光盘驱动器
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Application No.: US11500391Application Date: 2006-08-08
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Publication No.: US07511887B2Publication Date: 2009-03-31
- Inventor: Toshiyuki Kawasaki , Shigeru Oohchida , Tsuyoshi Suzudo , Koji Mori
- Applicant: Toshiyuki Kawasaki , Shigeru Oohchida , Tsuyoshi Suzudo , Koji Mori
- Applicant Address: JP Tokyo
- Assignee: Ricoh Company, Ltd.
- Current Assignee: Ricoh Company, Ltd.
- Current Assignee Address: JP Tokyo
- Agency: Dickstein Shapiro LLP
- Priority: JP2002-295642 20021009; JP2002-380750 20021227
- Main IPC: G02B5/18
- IPC: G02B5/18
Abstract:
A diffraction grating with periodically arranged protrusions and grooves at a relatively narrow pitch and improved diffraction efficiency is disclosed. The protrusions of the grating are made of a material whose index of refraction is greater than that of the grooves, and the ratio of the width D of the protrusion to the pitch Λ of the protrusion is set equal to or less than 0.4 (D/Λ≦0.4).
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