Patent US4088953A successfully refreshed from Google Patents.
Patent US4634219A successfully refreshed from Google Patents.
US4634219A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical low-pass filter
Assignee: Canon Inc
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Filing: 1986-04-04
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Granted: 1987-01-06
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Expires: 2006-04-04
Abstract
Abstract An optical low-pass filter has a diffraction grating structure wherein flat faces which are perpendicular to the optical axis of an imaging lens and slanting faces which are slanting relative to the flat faces are at a predetermined pitch.
Inventors
- 👤 Takashi Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:24
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/18; G02B5/1866; G02B5/1871; G02B27/00; G02B27/42; G02B27/46
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
80 words
An optical low-pass filter having a blazed diffraction grating structure arranged in an image-forming light beam, said diffraction grating structure being assymetrical and being formed of plural diffraction elements, each element comprising a first face almost perpendicular to the optical axis of the light beam, a second face inclined thereto, and a third face arranged almost parallel to said optical axis, said plural elements being arranged so that said first and second faces of said elements have a predetermined pitch.
Claim 2
Dependent Claim
80 words
An optical low-pass filter having a blazed diffraction grating structure arranged in an image-forming light beam, said diffraction grating structure being assymetrical and being formed of plural diffraction elements, each element comprising a first face almost perpendicular to the optical axis of the light beam, a second face inclined thereto, and a third face arranged almost parallel to said optical axis, said plural elements being arranged so that said first and second faces of said elements have a predetermined pitch.
Claim 3
Dependent Claim
18 words
An optical low-pass filter according to claim 1, wherein the first faces are arranged in an embedded state.
Claim 4
Dependent Claim
90 words
An optical low-pass filter having a blazed diffraction grating structure arranged in an image-forming light beam, said diffracton grating structure being assymetrical and being formed of plural diffraction elements, each element comprising a first face almost perpendicular to the optical axis of the light beam, a second face inclined thereto, and a third face almost parallel to said optical axis, said third faces being arranged between said first and second faces, said plural elements being arranged so that said first and second faces of said elements have a predetermined pitch.
Claim 5
Dependent Claim
90 words
An optical low-pass filter having a blazed diffraction grating structure arranged in an image-forming light beam, said diffracton grating structure being assymetrical and being formed of plural diffraction elements, each element comprising a first face almost perpendicular to the optical axis of the light beam, a second face inclined thereto, and a third face almost parallel to said optical axis, said third faces being arranged between said first and second faces, said plural elements being arranged so that said first and second faces of said elements have a predetermined pitch.
Claim 6
Dependent Claim
100 words
An optical low-pass filter having a blazed diffraction grating structure arranged in an image forming light beam, said diffraction grating structure being assymetrical and being formed of plural diffraction elements, each element comprising a first face almost perpendicular to the optical axis of the light beam, a second face inclined thereto, and a third face arranged almost parallel to the optical axis, said first faces for emitting zero-order diffraction light, said second faces for emitting a diffracted light, said first and second faces being arranged with a predetermined pitch for concentrating the intensity of the diffracted light in two directions.
Claim 7
Dependent Claim
100 words
An optical low-pass filter having a blazed diffraction grating structure arranged in an image forming light beam, said diffraction grating structure being assymetrical and being formed of plural diffraction elements, each element comprising a first face almost perpendicular to the optical axis of the light beam, a second face inclined thereto, and a third face arranged almost parallel to the optical axis, said first faces for emitting zero-order diffraction light, said second faces for emitting a diffracted light, said first and second faces being arranged with a predetermined pitch for concentrating the intensity of the diffracted light in two directions.
References Cited (Backward Citations)
GB1394712A
Cited
US3821795A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-01-05 | 1990-07-07 | 1991-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-05 | 1994-07-07 | 1995-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-05 | 1998-07-07 | 1999-01-06 | $7700.00 | Window Closed / Lapsed |