US4636627A
Expired / Lapsed
US
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Focus detecting apparatus
Assignee: Canon Inc
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Filing: 1984-01-11
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Granted: 1987-01-13
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Expires: 2004-01-11
Abstract
Abstract In a focus detecting apparatus wherein an imaging optical system is disposed rearwardly of the predetermined imaging plane of an objective lens to thereby form a plurality of object images on the basis of lights passed through different portions of the pupil of the objective lens and each of the object images is detected by a line sensor comprising a plurality of photoelectric conversion elements to thereby detect the focus condition of the objective lens from the amount of deviation of each object image, a field limitation plate having a plurality of openings and an optical filter for causing the characteristics of the light passed through the openings of the field limitation plate to differ from one another are provided near the predetermined imaging plane of the objective lens. Thus, the apparatus is adaptable for different focus detection conditions and is very simple in construction.
Inventors
- 👤 Susumu Matsumura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:47
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/34; G02B7/343
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
117 words
A focus detecting apparatus for detecting the focus condition of an objective lens, comprising: (a) light intercepting means having a plurality of openings such that a stream of light passes from said objective lens through each opening, said light intercepting means disposed near a predetermined imaging plane of said objective lens; (b) imaging means for forming a plurality of images on the basis of each of the light streams passing through the openings of said light intercepting means; (c) filter means for causing an optical characteristic of the light streams passing through the openings of said light intercepting means to differ from one another; and (d) sensing means for sensing the images formed by said imaging means.
Claim 2
Dependent Claim
117 words
A focus detecting apparatus for detecting the focus condition of an objective lens, comprising: (a) light intercepting means having a plurality of openings such that a stream of light passes from said objective lens through each opening, said light intercepting means disposed near a predetermined imaging plane of said objective lens; (b) imaging means for forming a plurality of images on the basis of each of the light streams passing through the openings of said light intercepting means; (c) filter means for causing an optical characteristic of the light streams passing through the openings of said light intercepting means to differ from one another; and (d) sensing means for sensing the images formed by said imaging means.
Claim 3
Dependent Claim
64 words
An apparatus according to claim 1, wherein said filter means renders an image formed on the basis of a first light stream passing through a first of the openings of said light intercepting means into a visible light image and renders an image formed on the basis of a second light stream passing through a second of the openings into an infrared light image.
Claim 4
Dependent Claim
36 words
An apparatus according to claim 2, wherein said filter means has a first portion which transmits visible light therethrough and intercepts infrared light and a second portion which transmits infrared light therethrough and intercepts visible light.
Claim 5
Dependent Claim
18 words
An apparatus according to claim 3, wherein said filter means is disposed proximate to said light intercepting means.
Claim 6
Dependent Claim
17 words
An apparatus according to claim 3, wherein said filter means is disposed proximate to said sensing means.
Claim 7
Dependent Claim
21 words
An apparatus according to claim 3, wherein said filter means is disposed between said light intercepting means and said sensing means.
Claim 8
Dependent Claim
254 words
A focus detecting apparatus for detecting the focus condition of an objective lens, comprising: (a) light intercepting means having a plurality of openings such that a stream of light passes from said objective lens through each opening, said light intercepting means disposed near a predetermined imaging plane of said objective lens; (b) imaging means for forming a plurality of images on the basis of each of the light streams passing through the openings of said light intercepting means. (c) filter means for causing an optical characteristic of the light streams passing through the openings of said light intercepting means to differ from one another, said filter means having a plurality of polarizing portions having different polarization axes; (d) separating means for causing said imaging means to form an image on the basis of a first light stream passing through a first of the openings of said light intercepting means and an image on the basis of a second light stream passing through a second of the openings separately from each other, said separating means having a plurality of polarizing portions, the polarization axis of a first of said separating means polarizing portions being in the same direction as the polarization axis of a first of said filter means polarizing portions and the polarization axis of a second of said separating means polarizing portions being in the same direction as the polarization axis of a second of said filter means polarizing portions; and (e) sensing means for sensing the images formed by said imaging means.
Claim 9
Dependent Claim
254 words
A focus detecting apparatus for detecting the focus condition of an objective lens, comprising: (a) light intercepting means having a plurality of openings such that a stream of light passes from said objective lens through each opening, said light intercepting means disposed near a predetermined imaging plane of said objective lens; (b) imaging means for forming a plurality of images on the basis of each of the light streams passing through the openings of said light intercepting means. (c) filter means for causing an optical characteristic of the light streams passing through the openings of said light intercepting means to differ from one another, said filter means having a plurality of polarizing portions having different polarization axes; (d) separating means for causing said imaging means to form an image on the basis of a first light stream passing through a first of the openings of said light intercepting means and an image on the basis of a second light stream passing through a second of the openings separately from each other, said separating means having a plurality of polarizing portions, the polarization axis of a first of said separating means polarizing portions being in the same direction as the polarization axis of a first of said filter means polarizing portions and the polarization axis of a second of said separating means polarizing portions being in the same direction as the polarization axis of a second of said filter means polarizing portions; and (e) sensing means for sensing the images formed by said imaging means.
Claim 10
Dependent Claim
35 words
An apparatus according to claim 7, wherein the polarizing portions of said separating means are provided so as to correspond to the central portion and outer peripheral portion of the pupil of said objective lens.
Claim 11
Dependent Claim
17 words
An apparatus according to claim 8, wherein said separating means is disposed proximate to said imaging means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1990-01-12 | 1990-07-14 | 1991-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-12 | 1994-07-14 | 1995-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-12 | 1998-07-14 | 1999-01-13 | $7700.00 | Window Closed / Lapsed |