US3824005A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for refracting eyes
Assignee: Individual
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Filing: 1973-03-28
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Granted: 1974-07-16
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Expires: 1993-03-28
Abstract
Abstract Apparatus is provided to project a pattern of bars of light through a lens system into a subject''s eye. The reflection of the pattern from the retina of the eye is passed back through the lens of the eye and through a second pattern system to a detector. The pattern of bars of light is continuously moved back and forth axially of the subject''s eye to bring the pattern into focus on the retina once during its travel from one extreme to another. The second pattern system through which the reflected pattern passes is similar to the pattern of the bars of light in that it has a series of slots corresponding in size and position to the bars of light of the first pattern. This second pattern is vibrated sideways at a rapid speed to chop the pattern of light reflected from the retina so that a modulated light image which rises to a peak each time the pattern of bars of light is in focus on the retina of the subject''s eye is supplied to the detector. The detector transmits an electric signal corresponding to the intensity of light received by it to electronic circuitry which determines the position of the primary pattern when it is in focus on the retina of the subject''s eye and provides a readout in diopters indicating the refractive state of the subject''s eye.
Inventors
- 👤 J Woestman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:37
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/103; A61B3/12; A61B3/13; A61B3/135
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
285 words
A refractometer for the objective determination of the refractive state of a subject''s eye, comprising: image forming means to form an image of a light pattern and project said image into the subject''s eye and to the retina of the eye, means to uniformly vary the position of said image forming means back and forth along the optical axis of the subject''s eye at a regular frequency from a central position in which the image is in focus on the retina of an emetropic eye to opposite limit positions at opposite sides of said central position with the image in focus on the retina of a hyperopic eye during movement to one limit position and in focus on the retina of a myopic eye during movement to the other limit position, a detector for determining the intensity of light received by it, said detector operable to transmit a signal varying in streNgth in proportion to the intensity of light received by it, means to direct at least a portion of the light pattern of said image reflected from the retina of the subject''s eye to said detector, means positioned along the path of travel of the reflected light between the eye and the detector to rapidly interrupt the reflected light at substantially shorter intervals than the frequency of movement of the image forming means to provide to the detector a series of peaks of light with the peaks varying with the intensity of the reflected light, and means to determine the position of the image forming means at the same time the intensity of the light reflected from the retina of the eye and the peaks of light received by the detector are a maximum.
Claim 2
Dependent Claim
285 words
A refractometer for the objective determination of the refractive state of a subject''s eye, comprising: image forming means to form an image of a light pattern and project said image into the subject''s eye and to the retina of the eye, means to uniformly vary the position of said image forming means back and forth along the optical axis of the subject''s eye at a regular frequency from a central position in which the image is in focus on the retina of an emetropic eye to opposite limit positions at opposite sides of said central position with the image in focus on the retina of a hyperopic eye during movement to one limit position and in focus on the retina of a myopic eye during movement to the other limit position, a detector for determining the intensity of light received by it, said detector operable to transmit a signal varying in streNgth in proportion to the intensity of light received by it, means to direct at least a portion of the light pattern of said image reflected from the retina of the subject''s eye to said detector, means positioned along the path of travel of the reflected light between the eye and the detector to rapidly interrupt the reflected light at substantially shorter intervals than the frequency of movement of the image forming means to provide to the detector a series of peaks of light with the peaks varying with the intensity of the reflected light, and means to determine the position of the image forming means at the same time the intensity of the light reflected from the retina of the eye and the peaks of light received by the detector are a maximum.
Claim 3
Dependent Claim
39 words
Apparatus in accordance with claim 1 in which the image is a pattern of bars of light of predetermined length and width with the spacing between adjacent bars of light equal to the width of the bars of light.
Claim 4
Dependent Claim
77 words
Apparatus in accordance with claim 2, in which the means along the passage of reflected light intermediate the eye and the detector to rapidly interrupt the light comprises a movable patterned grid lying in a plane normal to the direction of the path of travel of the reflected light with the grid having a series of slots therein equal in number and length and width and spacing to the pattern of bars of light in said image.
Claim 5
Dependent Claim
92 words
Apparatus in accordance with claim 3 including means to move said patterned grid within said plane normal to the direction of travel of said reflected light and in a direction at right angles to the long axis of said slots, said means to move said patterned grid operable to move the grip equal to the width of the slots between a first position in which the pattern of bars of light coincide with said slots to a second position in which the bars of light of said pattern lie between said slots.
Claim 6
Dependent Claim
62 words
Apparatus in accordance with claim 1 including a quarter wave length polarizer positioned between said image forming means and the eye to polarize the light of said image in a predetermined direction, and a beam splitter positioned intermediate the polarizer and the eye to receive light reflected back from the eye and direct polarized light reflected from the retina toward the detector.
Claim 7
Dependent Claim
80 words
Apparatus in accordance with claim 1 including means responsive to the position of said image forming means to transmit a first electric signal whose voltage varies with the position of said image forming means, and in which said detector transmits a second electric signal whose voltage varies with the intensity of light received by said detector, the voltage of said second electric signal being at a maximum when the intensity of light received by the detector is at a maximum.
Claim 8
Dependent Claim
57 words
Apparatus in accordance with claim 6 including electronic circuitry to receive said first and said second electric signals, said circuitry operable to provide an indication of the position of said image forming means along its path of travel between its opposite limit positions at the time the voltage of said second electric signal is at its maximum.
Claim 9
Dependent Claim
83 words
Apparatus in accordance with claim 7 in which said electronic circuitry amplifies said second electric signal received by it from said detector, converts said amplified signal to a wave form following the change of intensity of light reflected from the retina, shifts the phase of said wave form 90*, determines when said shifted wave form passes through its zero point, and transmits a predetermined signal each time said shifted wave form passes through its zero point indicating maximum intensity of the reflected light.
Claim 10
Dependent Claim
34 words
Apparatus in accordance with claim 8 in which said electronic circuitry includes means to constantly sample the voltage of said first electric signal and hold the sampled voltage upon receipt of said predetermined signal.
Claim 11
Dependent Claim
55 words
Apparatus in accordance with claim 9 in which said electronic circuitry includes display means to provide a visual display of the sAmple of said voltage held upon receipt of said predetermined signal, said display means operable to convert said sampled and held voltage to a visual reading indicating the refractive state of the subject''s eye.
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) | 1977-07-15 | 1978-01-14 | 1978-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-15 | 1982-01-14 | 1982-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-15 | 1986-01-14 | 1986-07-16 | $7700.00 | Window Closed / Lapsed |