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US4795236A
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Optical low pass filter utilizing a phase grating
Assignee: Sony Corp
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Filing: 1985-12-20
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Granted: 1989-01-03
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Expires: 2005-12-20
Abstract
Abstract An optical low pass filter including a phase grating, wherein the grating is implanted inwardly from the surface of a substrate, the grating having a uniform repetitive period and having a refractive index different from that of the substrate.
Inventors
- 👤 Kouichi Ise
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:12
CPC Classifications
G; G02; G02F; G02F2/00; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/122; G02B6/124; G02B27/00; G02B27/42; G02B27/46; G02B5/00; G02B5/18; G02B5/1866; G02B5/1871
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
100 words
An optical low pass filter provided between an image source and an image pickup device including: a substrate having a pair of major surfaces, a grating implanted within said substrate and having a surface flush with one of said major surfaces, said grating having a uniform repetitive period and having a refractive index different from that of said substrate, one of said major surfaces receiving image light from said image source and said optical low pass filter deriving image light with a suppressed spatial frequency component higher than a predetermined spatial frequency to be supplied to said image pickup device.
Claim 2
Dependent Claim
100 words
An optical low pass filter provided between an image source and an image pickup device including: a substrate having a pair of major surfaces, a grating implanted within said substrate and having a surface flush with one of said major surfaces, said grating having a uniform repetitive period and having a refractive index different from that of said substrate, one of said major surfaces receiving image light from said image source and said optical low pass filter deriving image light with a suppressed spatial frequency component higher than a predetermined spatial frequency to be supplied to said image pickup device.
Claim 3
Dependent Claim
15 words
An optical filter according to claim 1 wherein said grating consists of a stripe-like pattern.
Claim 4
Dependent Claim
59 words
An optical filter according to claim 1 which includes a pair of gratings formed in each of said major surfaces of said substrate, one of said gratings being oriented on one direction and the other grating being oriented in a direction perpendicular to said one direction, each of said pair of gratings having a period different from each other.
Claim 5
Dependent Claim
40 words
An optical filter according to claim 1 wherein the refractive index N of said grating and the refractive index N o of said substrate along the x, y and z axes have the following relationship: O<N (x, y, z)-N.sub.o ≦0.2
Claim 6
Dependent Claim
40 words
An optical filter according to claim 1 which includes gratings in one major surface extending in a plurality of rows and gratings in the other major surface extending in rows which are perpendicular to the rows of said one surface.
Claim 7
Dependent Claim
110 words
An optical low pass filter provided between an image source and an image pickup device comprising: a substrate composed of glass having a pair of major surfaces thereon, a phase grating formed within said substrate and having a surface flush with one of said major surfaces, said grating having a uniform repetitive period and formed of a glass having a refractive index different from that of said substrate, wherein one of said major surfaces receives image light from said image source and said optical low pass filter derives image light having a supressed spatial frequency component higher than a predetermined spatial frequency to be applied to said image pickup device.
Claim 8
Dependent Claim
110 words
An optical low pass filter provided between an image source and an image pickup device comprising: a substrate composed of glass having a pair of major surfaces thereon, a phase grating formed within said substrate and having a surface flush with one of said major surfaces, said grating having a uniform repetitive period and formed of a glass having a refractive index different from that of said substrate, wherein one of said major surfaces receives image light from said image source and said optical low pass filter derives image light having a supressed spatial frequency component higher than a predetermined spatial frequency to be applied to said image pickup device.
Claim 9
Dependent Claim
22 words
An optical low pass filter according to claim 6, wherein said grating contains a different metal element from that of said substrate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-01-03 | 1992-07-04 | 1993-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-01-03 | 1996-07-04 | 1997-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-01-03 | 2000-07-04 | 2001-01-03 | $7700.00 | Window Closed / Lapsed |