US5701286A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Super-resolution optical head device which produces side spots without side lobes
Assignee: NEC Corp
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Filing: 1996-04-04
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Granted: 1997-12-23
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Expires: 2016-04-04
Abstract
Abstract A super-resolution optical head device includes a diffraction grating having central and peripheral areas. The central area suppresses zero order diffracted light and produces ±1th order diffracted light. The peripheral area produces both zero order diffracted light and ±1th order diffracted light. The ±1th order diffracted light from the central and peripheral areas forms side light beams without an aperture. The side light beams form side spots on a recording medium. The side spots are not accompanied by side lobes because the side light beams do not have an aperture therein.
Inventors
- 👤 Masahiko Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:54
CPC Classifications
B; B82; B82Y; B82Y10/00; G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1381; G11B7/1353
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
151 words
A super-resolution optical head device receiving an incident light beam from a light source and forming a first light beam and a pair of second light beams, said incident light beam comprising central and peripheral portions, said super-resolution optical head device comprising: a diffraction grating having first and second areas, said first area of said diffraction grating suppressing zero order diffracted light and producing ±1th diffracted light, and said second area of said diffraction grating producing zero and ±1th order diffracted light, wherein said first and second areas of said diffraction grating receive said central and peripheral portions of said incident light beam, respectively, the zero order diffracted light from said second area of said diffraction grating forms said first light beam with an aperture, and the ±1th order diffracted light from said first and second areas of said diffraction grating forms said pair of second light beams without an aperture.
Claim 2
Dependent Claim
151 words
A super-resolution optical head device receiving an incident light beam from a light source and forming a first light beam and a pair of second light beams, said incident light beam comprising central and peripheral portions, said super-resolution optical head device comprising: a diffraction grating having first and second areas, said first area of said diffraction grating suppressing zero order diffracted light and producing ±1th diffracted light, and said second area of said diffraction grating producing zero and ±1th order diffracted light, wherein said first and second areas of said diffraction grating receive said central and peripheral portions of said incident light beam, respectively, the zero order diffracted light from said second area of said diffraction grating forms said first light beam with an aperture, and the ±1th order diffracted light from said first and second areas of said diffraction grating forms said pair of second light beams without an aperture.
Claim 3
Dependent Claim
22 words
A super-resolution optical head device according to claim 1, wherein said first and second areas of said diffraction grating have different structures.
Claim 4
Dependent Claim
58 words
A super-resolution optical head device according to claim 2, wherein said diffraction grating has convex and concave portions, and wherein said first and second areas of said diffraction grating are distinct from each other in at least one of a height of said convex portion, a width of said convex portion, and a width of said concave portion.
Claim 5
Dependent Claim
23 words
A super-resolution optical head device according to claim 3, wherein said first and second areas of said diffraction grating have the same pitch.
Claim 6
Dependent Claim
35 words
A super-resolution optical head device according to claim 1, further comprising: a filter interposed between the light source and said diffraction grating for reducing an intensity of said central portion of said incident light beam.
Claim 7
Dependent Claim
18 words
A super-resolution optical head device according to claim 5, wherein said filter is integrated into said diffraction grating.
Claim 8
Dependent Claim
66 words
A super-resolution optical head device according to claim 5, wherein each of said second light beams has central and peripheral portions, the ±1th order diffracted light from said first area of said diffraction grating forms said central portion of said second light beams, and the ±1th order diffracted light from said second area of said diffraction grating forms said peripheral portion of said second light beams.
Claim 9
Dependent Claim
31 words
A super-resolution optical head device according to claim 7, wherein a transmissivity of said filter is adapted so that said central and peripheral portions of said second light beams connect smoothly.
Claim 10
Dependent Claim
23 words
A super-resolution optical head device according to claim 1, wherein said diffraction grating receives said incident light beam from said light source directly.
Claim 11
Dependent Claim
47 words
A super-resolution optical head device according to claim 1, wherein said diffraction grating further comprises third and fourth areas having the same structure as said first and second areas, respectively, and said first, second, and third areas are surrounded by said second, third, and fourth areas, respectively.
Claim 12
Dependent Claim
33 words
A super-resolution optical head device according to claim 1, wherein said diffraction grating has a pair of said second areas, and said first area is interposed between said pair of said second areas.
Claim 13
Dependent Claim
37 words
A super-resolution optical head device according to claim 1, further comprising: a collimating lens interposed between the light source and said diffraction grating for converting said incident light beam from said light source into parallel ray light.
References Cited (Backward Citations)
US5153873A
Cited
JPH01315041A
Cited
JPH01315040A
Cited
US5113286A
Cited
US5349592A
Cited
US5434840A
Cited
US5612942A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-12-22 | 2001-06-23 | 2001-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-12-22 | 2005-06-23 | 2005-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-12-22 | 2009-06-23 | 2009-12-23 | $7700.00 | Window Closed / Lapsed |