US5576780A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for evaluation of length of focus of the eye
Assignee: DAPHNE EYE INSTRUMENTS
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Filing: 1995-06-06
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Granted: 1996-11-19
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Expires: 2015-06-06
Abstract
Abstract An autorefractor utilizes two light emitters and corresponding optics to project images onto the fundus, with the focus of these images bracketing the gross sphere of an emmetrope. A single detector generates a signal corresponding to each emitter. In an alternate embodiment, a single emitter and two detectors having foci bracketing the gross sphere of an emmetrope generate a signal corresponding to each detector. The light reflected from the fundus is detected and the differential intensities of two signals are used to determine departure in refraction from 0 diopter sphere. Multi-segmented or CCD detectors may be used to measure cylinder/axis, determine length and direction of gaze (in combination with a Purkinje image sensor) and to generate and analyze retinal images.
Inventors
- 👤 Don R. Yancey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:16
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/12; A61B3/1208; A61B3/103; A61B3/14; A61B3/15; A61B3/156; A61B3/158
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
229 words
In an interactive virtual reality imaging system, a process for determining length of focus of an eye of a system user for adapting focus of an image generated by the imaging system, wherein said eye has a lens, a cornea and a retina, the process comprising: identifying an optical path to the retina of said eye; projecting a first image along said optical path to the retina of said eye, said first image being focused at a first focal point along said optical path beyond the retina of said eye; detecting said first image from said optical path reflected from the retina of said eye and generating a first signal proportional to an intensity of said first image; projecting a second image along said optical path to the retina of said eye, said second image being focused at a second focal point along said optical path in front of the retina of said eye; detecting said second image from said optical path reflected from the retina of the eye and generating a second signal proportional to an intensity of said second image; comparing said first and second signals for indicating a relative intensity of said first and second images to determine an accommodation of said eye to provide the system user's length of focus; and adjusting the focus of the image to correspond to the user's length of focus.
Claim 2
Dependent Claim
229 words
In an interactive virtual reality imaging system, a process for determining length of focus of an eye of a system user for adapting focus of an image generated by the imaging system, wherein said eye has a lens, a cornea and a retina, the process comprising: identifying an optical path to the retina of said eye; projecting a first image along said optical path to the retina of said eye, said first image being focused at a first focal point along said optical path beyond the retina of said eye; detecting said first image from said optical path reflected from the retina of said eye and generating a first signal proportional to an intensity of said first image; projecting a second image along said optical path to the retina of said eye, said second image being focused at a second focal point along said optical path in front of the retina of said eye; detecting said second image from said optical path reflected from the retina of the eye and generating a second signal proportional to an intensity of said second image; comparing said first and second signals for indicating a relative intensity of said first and second images to determine an accommodation of said eye to provide the system user's length of focus; and adjusting the focus of the image to correspond to the user's length of focus.
Claim 3
Dependent Claim
64 words
The process of claim 1 further including tracking a gaze direction of the system user, comprising: projecting a Purkinje image along said optical path focused in a vicinity of the cornea of said eye; receiving a reflected Purkinje image at least from the cornea of said eye along said optical path; and comparing alignment of the projected Purkinje image with the reflected Purkinje image.
Claim 4
Dependent Claim
23 words
The process of claim 1 wherein each of the steps of detecting the first and second images comprise detecting with a multi-segmented photodiode.
Claim 5
Dependent Claim
25 words
The process of claim 1 wherein each of the steps of detecting the first and second images comprise detecting with at least one CCD imager.
Claim 6
Dependent Claim
226 words
In an interactive virtual reality imaging system, a process for focusing a scene created by the system with a length of focus of an eye of a system user, wherein said eye has a lens, a cornea and a retina, the process comprising: identifying an optical path to the eye; projecting a first image along said optical path to the retina of said eye, said first image being focused at the retina of said eye; detecting said first image from said optical path reflected from the retina of said eye with a first detector having a focus corresponding to a first focal point along said optical path beyond the retina of the eye and generating a first signal S1 proportional to an intensity of a first reflection of said first image; detecting said first image from said optical path reflected from the retina of said eye with a second detector having a focus corresponding to a second focal point along said optical path in front of said retina and generating a second signal S2 proportional to an intensity of a second reflection of said first image; comparing said first and second signals according to the relationship (S1-S2)/(S1+S2) to determine accommodation of said eye to provide the system user's length of focus; and adjusting the focus of the scene to correspond to the user's length of focus.
Claim 7
Dependent Claim
226 words
In an interactive virtual reality imaging system, a process for focusing a scene created by the system with a length of focus of an eye of a system user, wherein said eye has a lens, a cornea and a retina, the process comprising: identifying an optical path to the eye; projecting a first image along said optical path to the retina of said eye, said first image being focused at the retina of said eye; detecting said first image from said optical path reflected from the retina of said eye with a first detector having a focus corresponding to a first focal point along said optical path beyond the retina of the eye and generating a first signal S1 proportional to an intensity of a first reflection of said first image; detecting said first image from said optical path reflected from the retina of said eye with a second detector having a focus corresponding to a second focal point along said optical path in front of said retina and generating a second signal S2 proportional to an intensity of a second reflection of said first image; comparing said first and second signals according to the relationship (S1-S2)/(S1+S2) to determine accommodation of said eye to provide the system user's length of focus; and adjusting the focus of the scene to correspond to the user's length of focus.
Claim 8
Dependent Claim
59 words
The process of claim 5 further comprising the steps of: projecting a second image along said optical path focused in a vicinity of the cornea of said eye; receiving a reflected second image from the cornea at at least one detector; and comparing alignment of the incident and reflected second images to determine the system user's directions of gaze.
Claim 9
Dependent Claim
54 words
The process of claim 6 wherein said at least one detector comprises two detectors, each detector generating an output signal and further comprising the steps of: summing the output signals of the two detectors; and providing a signal when the sum of the output signals varies from a preselected constant to indicate improper alignment.
Claim 10
Dependent Claim
13 words
The process of claim 6 where said second image is a Purkinje image.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-11-19 | 2000-05-20 | 2000-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-11-19 | 2004-05-20 | 2004-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-11-19 | 2008-05-20 | 2008-11-19 | $7700.00 | Window Closed / Lapsed |