Source: http://www.google.com/patents/US6545823?dq=6377161
Timestamp: 2016-06-29 15:12:51
Document Index: 114071681

Matched Legal Cases: ['Application No. 2001', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15']

Patent US6545823 - Double-wavelength aperture restricting filter and optical pickup apparatus ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsA double-wavelength aperture restricting filter has a zonal part adapted to act such that one wavelength λ1 of light keeps the quantity of light in an outer peripheral part of the luminous flux thereof whereas the other wavelength λ2 of light apparently extinguishes this quantity of light by an interference...http://www.google.com/patents/US6545823?utm_source=gb-gplus-sharePatent US6545823 - Double-wavelength aperture restricting filter and optical pickup apparatus using the sameAdvanced Patent SearchPublication numberUS6545823 B2Publication typeGrantApplication numberUS 09/986,013Publication dateApr 8, 2003Filing dateNov 7, 2001Priority dateJan 29, 2001Fee statusLapsedAlso published asUS20020145812Publication number09986013, 986013, US 6545823 B2, US 6545823B2, US-B2-6545823, US6545823 B2, US6545823B2InventorsYou KitaharaOriginal AssigneeFuji Photo Optical Co., Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (2), Referenced by (18), Classifications (22), Legal Events (6) External Links: USPTO, USPTO Assignment, EspacenetDouble-wavelength aperture restricting filter and optical pickup apparatus using the same
US 6545823 B2Abstract
A double-wavelength aperture restricting filter has a zonal part adapted to act such that one wavelength λ1 of light keeps the quantity of light in an outer peripheral part of the luminous flux thereof whereas the other wavelength λ2 of light apparently extinguishes this quantity of light by an interference effect. The zonal part has such a step that light supposed to pass a position corresponding to the zonal part if the zonal part does not exist and light passing a position at which the zonal part is formed if the zonal part exists generate therebetween a phase difference satisfying predetermined conditional expressions, whereas the circle formed by a step boundary has a diameter residing between two luminous flux diameters desired in two systems used for the wavelengths λ1 and λ2, respectively.
This application claims the priority of Japanese Patent Application No. 2001-19943 filed on Jan. 29, 2001, which is incorporated herein by reference.
In view of the foregoing circumstances, it is an object of the present invention to provide a double-wavelength aperture restricting filter which, for two systems having respective numerical apertures and wavelengths of light in use different from each other, can pass therethrough the respective wavelengths of light in use as luminous fluxes corresponding to their corresponding desirable numerical apertures by a simple configuration.
Δλ1 =mλ 1+δ1 (1)
Δλ2=(2n+1)λ2/2+δ2 (2)
|δ1|≦0.2λ1 (3)
|δ2|≦0.2λ2 (4)
The double-wavelength aperture restricting filter may be formed from a plastic material.
FIGS. 1A and 1B are partial schematic views showing an optical pickup apparatus comprising the double-wavelength aperture restricting filter in accordance with Example 1;
Namely, with respect to the wavelength λ1 of light, the zonal part 15 acts such that the light passing through the part other than the zonal part 15 and the light passing through the zonal apart 15 yield a phase difference which is an integral multiple of the wavelength λ1, so as to cancel the apparent phase difference, thereby keeping the quantity of light as it is in the outer peripheral part of the luminous flux. With respect to the wavelength λ2 of light, on the other hand, the zonal part 15 has such a step that the light supposed to pass the position corresponding to the zonal part if the zonal part does not exist and the light passing the position at which the zonal part is formed if the zonal part exists generate a phase difference of (2n+1)�wavelength/2 where n is an integer (as in the following). Therefore, with respect to the wavelength λ2 of light, the light passing through the part other than the zonal part 15 and the light passing through the zonal part generate a phase difference which is an odd multiple of � wavelength in the outer peripheral part of the luminous flux, thus yielding an interference effect by which these wavelengths of light weaken each other, whereby the quantity of emitted light can be taken as one whose quantity of light is apparently reduced by thus canceled quantity of light. While the fundamental explanation of this action is provided in Teruji Ose, “Feature: Resolution Limit Overcoming Technique Expected for Practice—Ultra Resolution Optical System,” O plus E (September 1992), pp. 66-72, it will be explained here in terms of interference of light.
In order to obtain a luminous flux having a desirable diameter by causing an interference action in light having a Gaussian amplitude distribution, it is not necessary to strictly generate a phase difference at an even multiple of � wavelength for the wavelength λ1 of light, and a phase difference at an odd multiple of � wavelength for the wavelength λ2 of light. It is rather preferable for the phase differences to shift slightly in view of aberration occurring in the lens and the like. Preferably, the amount of shift is about 20%.
The double-wavelength aperture restricting filter in accordance with the present invention and the optical pickup apparatus using the same will now be explained specifically with reference to Examples.
FIGS. 1A and 1B are schematic views showing an optical pickup apparatus equipped with the double-wavelength aperture restricting filter in accordance with Example 1, while enlarging its part from the double-wavelength aperture restricting filter 14 to the optical disc 9. As shown in FIGS. 1A and 1B, the double-wavelength aperture restricting filter 14 in accordance with Example 1 has a zonal part 15, depressed on the objective lens side, in the outer peripheral portion of the surface on the objective lens side. For convenience of explanation, the step is exaggerated in FIGS. 1A and 1B (as in FIGS. 3A and 3B). In these drawings, X indicates the optical axis (as in FIGS. 3A and 3B and FIGS. 8A and 8B).
FIGS. 3A and 3B are schematic views showing an optical pickup apparatus equipped with the double-wavelength aperture restricting filter in accordance with Example 2, while enlarging its part from the double-wavelength aperture restricting filter 14 to the optical disc 9. As shown in FIGS. 3A and 3B, the double-wavelength aperture restricting filter 14 in accordance with Example 2 has a zonal part 15, protruded on the objective lens side, in the outer peripheral portion of the surface on the objective lens side. This apparatus uses the same objective lens 8 as that used in Example 1.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS6363037 *May 27, 1999Mar 26, 2002Hiroyuki YamazakiOptical pickup apparatus with objective lens having a phase shift sectionJPH1026726A Title not available* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS7086073 *Jun 16, 2003Aug 1, 2006Microsoft CorporationOptical storage media with embedded security deviceUS7414951 *Dec 28, 2005Aug 19, 2008Nec CorporationOptical head device and optical recording and reproducing apparatusUS7530083Oct 26, 2005May 5, 2009Microsoft CorporationOptical storage media with embedded security deviceUS7546616Apr 19, 2005Jun 9, 2009Microsoft CorporationOptical storage media with embedded security deviceUS7577077 *Aug 29, 2003Aug 18, 2009Konica CorporationOptical pickup apparatus and optical elementUS7715296Jul 3, 2008May 11, 2010Nec CorporationOptical head device and optical recording and reproducing apparatusUS7855945 *Jul 21, 2006Dec 21, 2010Konica CorporationOptical pickup apparatus and optical elementUS20020181366 *May 28, 2002Dec 5, 2002Nec CorporationOptical head device and optical recording and reproducing apparatusUS20040047269 *Aug 29, 2003Mar 11, 2004Konica CorporationOptical pickup apparatus and optical elementUS20040255317 *Jun 16, 2003Dec 16, 2004Microsoft CorporationOptical storage media with embedded security deviceUS20050185552 *Apr 19, 2005Aug 25, 2005Microsoft CorporationOptical storage media with embedded security deviceUS20060053434 *Oct 26, 2005Mar 9, 2006Microsoft CorporationOptical storage media with embedded security deviceUS20060080694 *Oct 26, 2005Apr 13, 2006Microsoft CorporationOptical storage media with embedded security deviceUS20060104187 *Dec 28, 2005May 18, 2006Ryuichi KatayamaOptical head device and optical recording and reproducing apparatusUS20060256673 *Jul 21, 2006Nov 16, 2006Konica CorporationOptical pickup apparatus and optical elementUS20070220537 *May 23, 2007Sep 20, 2007Microsoft CorporationCounterfeit-resistant portable storage media with embedded security deviceUS20080273445 *Jul 3, 2008Nov 6, 2008Ryuichi KatayamaOptical head device and optical recording and reproducing apparatusUS20090016198 *Jul 3, 2008Jan 15, 2009Ryuichi KatayamaOptical head device and optical recording and reproducing apparatus* Cited by examinerClassifications U.S. Classification359/738, 369/112.22, 369/44.14, G9B/7.102, 359/577International ClassificationG02B9/14, G02B5/30, G02B5/28, G02B9/12, G02B9/00, G11B7/00, G02B5/00, G02B9/62, G11B7/16, G11B7/135, G02B27/00, G11B7/125Cooperative ClassificationG11B2007/0006, G11B7/139, G11B7/1367European ClassificationG11B7/139, G11B7/1367Legal EventsDateCodeEventDescriptionNov 7, 2001ASAssignmentOwner name: FUJI PHOTO OPTICAL CO., LTD., JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KITAHARA, YOU;REEL/FRAME:012299/0097Effective date: 20011022Sep 15, 2006FPAYFee paymentYear of fee payment: 4Sep 9, 2010FPAYFee paymentYear of fee payment: 8Nov 14, 2014REMIMaintenance fee reminder mailedApr 8, 2015LAPSLapse for failure to pay maintenance feesMay 26, 2015FPExpired due to failure to pay maintenance feeEffective date: 20150408RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services