Patent US4146310A successfully refreshed from Google Patents.
US4146310A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ophthalmoscopic optical system
Assignee: Canon Inc
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Filing: 1977-02-24
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Granted: 1979-03-27
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Expires: 1997-02-24
Abstract
Abstract An ophthalmoscopic photographing and observing system eliminates rays of light reflected and scattered at the cornea and the crystalline lens of a human eye. An illuminating optical system is provided with light shielding stops at positions conjugate to the corneal surface, the iris, and the rear face of the crystalline lens of an eye being examined. The sizes of these light shielding stops are such that an image of the stop conjugate to the corneal surface covers an area on the cornea where the light reflected by the fundus of the eye passes through the cornea covered with an image of the stop which is conjugate to the corneal surface; an image of the stop which is conjugate to the rear surface of the crystalline lens covers an area on the rear face of the crystalline lens where the light reflected by the fundus of the eye passes through. A ring-shaped aperture stop is conjugate to the iris.
Inventors
- 👤 Yoshimi Kohayakawa
- 👤 Isao Matsumura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:51
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/14; A61B3/15; A61B3/156
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
217 words
An ophthalmoscopic optical system including: objective means which confronts an eye being examined; an image forming lens group which is arranged on the image side of said objective means; an illuminating system for illuminating the fundus of the eye, the illuminating system comprising at least one light source, a condenser lens and relay lens means; reflecting means which is disposed between said objective means and said image forming lens group and which serves to reflect the light emitted from said illuminating system toward said objective means; a mask stop having a circular aperture provided in said illuminating system and substantially conjugate to an iris of the eye; a first stop provided in said illuminating system at a position which is substantially conjugate with a rear surface of a crystalline lens of the eye, said first stop being large enough so its image covers an area on the rear surface of the crystalline lens through which photographic light reflected by the fundus of the eye passes; and a second stop provided in said illuminating system at a position which is substantially conjugate to a cornea of the eye, said second stop being arranged to be large enough so its image covers the area on the cornea through which photographic light reflected by the fundus of the eye passes.
Claim 2
Dependent Claim
217 words
An ophthalmoscopic optical system including: objective means which confronts an eye being examined; an image forming lens group which is arranged on the image side of said objective means; an illuminating system for illuminating the fundus of the eye, the illuminating system comprising at least one light source, a condenser lens and relay lens means; reflecting means which is disposed between said objective means and said image forming lens group and which serves to reflect the light emitted from said illuminating system toward said objective means; a mask stop having a circular aperture provided in said illuminating system and substantially conjugate to an iris of the eye; a first stop provided in said illuminating system at a position which is substantially conjugate with a rear surface of a crystalline lens of the eye, said first stop being large enough so its image covers an area on the rear surface of the crystalline lens through which photographic light reflected by the fundus of the eye passes; and a second stop provided in said illuminating system at a position which is substantially conjugate to a cornea of the eye, said second stop being arranged to be large enough so its image covers the area on the cornea through which photographic light reflected by the fundus of the eye passes.
Claim 3
Dependent Claim
61 words
An ophthalmoscopic optical system according to claim 1 wherein a movable mirror is positioned on the image side of said image forming lens group; and an effective photographing light flux directed by said image forming lens groups and reflected by said movable mirror is formed into an image on a photodetecting surface of a photodetecting means through a light transmitting system.
Claim 4
Dependent Claim
17 words
An ophthalmoscopic optical system according to claim 2 wherein said photodetecting means is sensitive to infrared rays.
Claim 5
Dependent Claim
21 words
An ophthalmoscopic optical system according to claim 1 wherein said first and second stops are arranged adjacent to said mask stop.
Claim 6
Dependent Claim
25 words
An ophthalmoscopic optical system according to claim 4, wherein said stop having the circular aperture includes a center obscuring zone that forms a ring-shaped opening.
Claim 7
Dependent Claim
25 words
An ophthalmoscopic optical system according to claim 1, wherein said stop having the circular aperture includes a center obscuring zone that forms a ring-shaped opening.
Claim 8
Dependent Claim
25 words
An ophthalmoscopic optical system according to claim 2, wherein said stop having the circular aperture includes a center obscuring zone that forms a ring-shaped opening.
Claim 9
Dependent Claim
25 words
An ophthalmoscopic optical system according to claim 3, whrein said stop having the circular aperture includes a center obscuring zone that forms a ring-shaped opening.
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) | 1982-03-26 | 1982-09-25 | 1983-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-26 | 1986-09-25 | 1987-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-26 | 1990-09-25 | 1991-03-27 | $7700.00 | Window Closed / Lapsed |