G11B7/1275- Two or more lasers having different wavelengths.G11B7/127- Lasers Multiple laser arrays.means for controlling the size or intensity of optical spots or optical traces laser control circuitry specially adapted for optical storage devices Modulators, e.g. G11B7/125- Optical beam sources therefor, e.g.step profile, contours of substrate or grooves, pitch variations, materials G02B5/1866- Transmission gratings characterised by their structure, e.g.holography, photolithography, exposure to electron or ion beams G02B5/1857- Manufacturing methods using exposure or etching means, e.g.G02B5/1833- Diffraction gratings comprising birefringent materials.G02B5/00- Optical elements other than lenses.G02B- OPTICAL ELEMENTS, SYSTEMS OR APPARATUS.G11B7/1353- Diffractive elements, e.g.
G11B7/135- Means for guiding the beam from the source to the record carrier or from the record carrier to the detector.forming of the optical beam spot or modulation of the optical beam
recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties Record carriers therefor G11B7/00- Recording or reproducing by optical means, e.g.G11B- INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER.Assignors: MORI, KOJI, SUZUDO, TSUYOSHI, KAWASAKI, TOSHIYUKI, OOHCHIDA, SHIGERU Publication of US20040125454A1 publication Critical patent/US20040125454A1/en Priority to US11/500,390 priority Critical patent/US20060268413A1/en Priority to US11/500,391 priority patent/US7511887B2/en Application granted granted Critical Publication of US7110180B2 publication Critical patent/US7110180B2/en Status Active legal-status Critical Current Adjusted expiration legal-status Critical Links ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.) Filing date Publication date Priority claimed from JP2002-295642 external-priority Priority claimed from JP2002295642A external-priority patent/JP3851253B2/en Priority claimed from JP2002380750A external-priority patent/JP2004212548A/en Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd Assigned to RICOH COMPANY, LTD. Original Assignee Ricoh Co Ltd Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.) ( en Inventor Toshiyuki Kawasaki Shigeru Oohchida Tsuyoshi Suzudo Koji Mori Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.) Granted Application number US10/679,479 Other versions US7110180B2
Dvd groove spacing light diffraction pdf#
Google Patents Diffraction grating, method of fabricating diffraction optical element, optical pickup device, and optical disk driveĭownload PDF Info Publication number US20040125454A1 US20040125454A1 US10/679,479 US67947903A US2004125454A1 US 20040125454 A1 US20040125454 A1 US 20040125454A1 US 67947903 A US67947903 A US 67947903A US 2004125454 A1 US2004125454 A1 US 2004125454A1 Authority US United States Prior art keywords grating diffraction pitch duty optical element Prior art date Legal status (The legal status is an assumption and is not a legal conclusion. Google Patents US20040125454A1 - Diffraction grating, method of fabricating diffraction optical element, optical pickup device, and optical disk drive US20040125454A1 - Diffraction grating, method of fabricating diffraction optical element, optical pickup device, and optical disk drive
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