Patent US5221835A successfully refreshed from Google Patents.
US5221835A
Expired / Lapsed
US
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Image reading apparatus having a reflective blazed diffraction grating with varied pitch
Assignee: Canon Inc
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Filing: 1992-06-04
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Granted: 1993-06-22
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Expires: 2012-06-04
Abstract
Abstract A color reading apparatus includes a reflection type one dimensional blazed diffraction grating for color separation which is provided on an optical path between an imaging optical system for focusing a color image on a photosensor, and the photosensor in which three line sensors are disposed on a common substrate. The pitch of the diffraction grating varies in a direction of the pitch so as to control the reflective diffraction angle from reflection points resulting from different incident angles on the diffraction grating and to prevent the occurrence of a blur of ±1st-order diffracted light in the pitch cross section on the diffraction grating.
Inventors
- 👤 Michitaka Setani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:50
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/48; H04N1/486; H04N1/488
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
76 words
An image reading apparatus comprising: a plural-line sensor including a plurality of one-dimensional sensor arrays disposed on a common substrate; an imaging optical system for focusing an image of an object on said plural-line sensor; and a reflective blazed diffraction grating, positioned between said imaging optical system and said plural-line sensor, for separating light from the object into a plurality of colors; wherein a pitch of said diffraction grating varies in a direction of the pitch.
Claim 2
Dependent Claim
76 words
An image reading apparatus comprising: a plural-line sensor including a plurality of one-dimensional sensor arrays disposed on a common substrate; an imaging optical system for focusing an image of an object on said plural-line sensor; and a reflective blazed diffraction grating, positioned between said imaging optical system and said plural-line sensor, for separating light from the object into a plurality of colors; wherein a pitch of said diffraction grating varies in a direction of the pitch.
Claim 3
Dependent Claim
23 words
An image reading apparatus according to claim 1, wherein the pitch of said diffraction grating varies continuously in the direction of the pitch.
Claim 4
Dependent Claim
36 words
An image reading apparatus according to claim 1, wherein the pitch of said diffraction grating varies continuously in the direction of the pitch relative to an incident angle of a light beam entering said diffraction grating.
Claim 5
Dependent Claim
39 words
An image reading apparatus according to claim 1, wherein the pitch of said diffraction grating varies continuously from a first end of said diffraction grating to a second end of said diffraction grating in the direction of the pitch.
Claim 6
Dependent Claim
34 words
An image reading apparatus according to claim 1, wherein said plurality of one-dimensional sensor arrays are separated by finite distances in a direction perpendicular to a direction of said plurality of one-dimensional sensor arrays.
Claim 7
Dependent Claim
38 words
An image reading apparatus according to claim 1, wherein said reflective blazed diffraction grating separates light from the object into the plurality of colors in a direction perpendicular to a direction of said plurality of one-dimensional sensor arrays.
Claim 8
Dependent Claim
29 words
An image apparatus according to claim 1, wherein the object is scanned in a sub-scanning direction which is perpendicular to a direction of said plurality of one-dimensional sensor arrays.
Claim 9
Dependent Claim
20 words
An image reading apparatus according to claim 1, wherein said reflective blazed diffraction grating comprises a one-dimensional blazed diffraction grating.
Claim 10
Dependent Claim
19 words
An image reading apparatus according to claim 1, wherein said imaging optical system comprises an exit telecentric optical system.
Claim 11
Dependent Claim
41 words
An image reading apparatus according to claim 1, wherein the pitch of said reflective blazed diffraction grating increases in succession from an optical axis center of said imaging optical system toward a peripheral field angle position of said imaging optical system.
Claim 12
Dependent Claim
41 words
An image reading apparatus according to claim 1, wherein a thickness of said reflective blazed diffraction grating increases in succession from an optical axis center of said imaging optical system toward a peripheral field angle position of said imaging optical system.
Claim 13
Dependent Claim
107 words
An image reading apparatus comprising: a plural-line sensor including a plurality of one-dimensional sensor arrays disposed on a common substrate; an imaging optical system for focusing an image of an object on said plural-line sensor; a reflective blazed diffraction grating, positioned between said imaging optical system and said plural-line sensor, for separating light from the object into a plurality of colors; and light amount correcting means, positioned in an optical path between the object and said plural-line sensor, for limiting an amount of passing light such that a first numerical aperture in a sub-scanning direction becomes smaller than a second numerical aperture in a main scanning direction.
Claim 14
Dependent Claim
107 words
An image reading apparatus comprising: a plural-line sensor including a plurality of one-dimensional sensor arrays disposed on a common substrate; an imaging optical system for focusing an image of an object on said plural-line sensor; a reflective blazed diffraction grating, positioned between said imaging optical system and said plural-line sensor, for separating light from the object into a plurality of colors; and light amount correcting means, positioned in an optical path between the object and said plural-line sensor, for limiting an amount of passing light such that a first numerical aperture in a sub-scanning direction becomes smaller than a second numerical aperture in a main scanning direction.
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) | 1996-06-21 | 1996-12-21 | 1997-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-21 | 2000-12-21 | 2001-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-21 | 2004-12-21 | 2005-06-22 | $7700.00 | Window Closed / Lapsed |