US4929076A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ophthalmic measuring apparatus
Assignee: Canon Inc
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Filing: 1989-04-24
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Granted: 1990-05-29
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Expires: 2009-04-24
Abstract
Abstract An ophthalmic measuring apparatus having a cornea shape measuring device and an eye refractive power device which are operated so that both the measurements of the shape of cornea and the eye refractive power may be effected simultaneously.
Inventors
- 👤 Takashi Masuda
- 👤 Kyoji Sekiguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:45
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/107
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
265 words
An ophthalmic measuring apparatus capable of both measuring the cornea shape and eye refractive power of an eye to be examined, comprising: (a) a cornea shape measuring system, having: (a1) a projecting optical system for projecting a target image onto the cornea of the eye to be examined, (a2) an imaging optical system for reproducing an image of the target reflected at the cornea, and (a3) light detecting means for detecting the reflected target image to measure the shape of the cornea, (b) a refractive power measuring system, having: (b1) a projection optical system for projecting a target image onto the fundus of the eye to be examined, (b2) an imaging optical system for reproducing a target image reflected by the fundus of the eye, wherein at least a part of the optical path of each of said imaging optical systems is shared by the other of said imaging optical systems, and (b3) light detecting means for detecting the reflected target image to measure the eye refractive power, and (c) a fixation chart projecting system, having: (c1) first fixation chart means for fixing the gazing axis of the eye during the measurement of the shape of the cornea of the eye, (c2) second fixation chart means for fixing the gazing axis of the eye during the measurement of the refractive power of the eye, and (c3) driving means for shifting a part of said fixation chart projecting system so that said first fixation chart means is projected from a position corresponding to the refractive power of the eye measured by said refractive power measuring system.
Claim 2
Dependent Claim
265 words
An ophthalmic measuring apparatus capable of both measuring the cornea shape and eye refractive power of an eye to be examined, comprising: (a) a cornea shape measuring system, having: (a1) a projecting optical system for projecting a target image onto the cornea of the eye to be examined, (a2) an imaging optical system for reproducing an image of the target reflected at the cornea, and (a3) light detecting means for detecting the reflected target image to measure the shape of the cornea, (b) a refractive power measuring system, having: (b1) a projection optical system for projecting a target image onto the fundus of the eye to be examined, (b2) an imaging optical system for reproducing a target image reflected by the fundus of the eye, wherein at least a part of the optical path of each of said imaging optical systems is shared by the other of said imaging optical systems, and (b3) light detecting means for detecting the reflected target image to measure the eye refractive power, and (c) a fixation chart projecting system, having: (c1) first fixation chart means for fixing the gazing axis of the eye during the measurement of the shape of the cornea of the eye, (c2) second fixation chart means for fixing the gazing axis of the eye during the measurement of the refractive power of the eye, and (c3) driving means for shifting a part of said fixation chart projecting system so that said first fixation chart means is projected from a position corresponding to the refractive power of the eye measured by said refractive power measuring system.
Claim 3
Dependent Claim
61 words
An opthalmic measuring apparatus according to claim 1, wherein said first fixation chart means for measuring the shape of the cornea is incorporated in said second fixation chart means for measuring the eye refractive power as a single fixation chart means and wherein said single fixation chart means is commonly used for the cornea shape measurement and the refractive power measurement.
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) | 1993-05-28 | 1993-11-27 | 1994-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-28 | 1997-11-27 | 1998-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-28 | 2001-11-27 | 2002-05-29 | $7700.00 | Window Closed / Lapsed |