Patent US2675894A successfully refreshed from Google Patents.
US5479221A
Expired / Lapsed
US
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Hand-held line grid interference retinometer
Assignee: Heine Optotechnik GmbH and Co KG
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Filing: 1994-05-26
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Granted: 1995-12-26
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Expires: 2014-05-26
Abstract
Abstract An apparatus for testing visual acuity, or clearness of vision, particularly when there is impaired refracting medium in an eye, includes a lamp (1) and a pin-hole diaphragm (4) arranged in a light-beam path downstream of the lamp with a single diffraction grating (6), being provided in the light-beam path downstream of the pin-hole diaphragm.
Inventors
- 👤 Helmut Heine
- 👤 Anton Schneider
- 👤 Otto H. Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:28
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/117
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
88 words
Apparatus for testing visual acuity of an eye of a patient, particularly when there is impaired refracting medium in the eye, comprising a light source (1) and a pin-hole diaphragm (4) arranged in a light-beam path downstream of the light source, wherein only a single diffraction line grid (6) is provided in the light-beam path following the pin-hole diaphragm (4) for creating a line pattern on a retina of the eye of the patient by causing a diffraction spectrum and creating an interference line pattern on the retina.
Claim 2
Dependent Claim
88 words
Apparatus for testing visual acuity of an eye of a patient, particularly when there is impaired refracting medium in the eye, comprising a light source (1) and a pin-hole diaphragm (4) arranged in a light-beam path downstream of the light source, wherein only a single diffraction line grid (6) is provided in the light-beam path following the pin-hole diaphragm (4) for creating a line pattern on a retina of the eye of the patient by causing a diffraction spectrum and creating an interference line pattern on the retina.
Claim 3
Dependent Claim
48 words
Apparatus as in claim 1 wherein is further included a plate (14) having a plurality of line discs each with only a single line grid arranged thereon about a concentric circular arc so that they can be individually, only one at a time, moved into the light-beam path.
Claim 4
Dependent Claim
32 words
Apparatus as in claim 1 wherein is further included a prism arranged in the light-beam path following the pin-hole diaphragm, which prism is rotatable about an axis parallel to the light-beam path.
Claim 5
Dependent Claim
28 words
Apparatus as in claim 1 wherein is further included a color filter which is arranged in the light-beam path between the light source and the following pin-hole diaphragm.
Claim 6
Dependent Claim
27 words
Apparatus as in claim 1 wherein at least one light diffuser is arranged in the light-beam path between the light source and the following pin hole diaphragm.
Claim 7
Dependent Claim
17 words
Apparatus as in claim 1 wherein the light source is a lamp having a frosted bulb surface.
Claim 8
Dependent Claim
20 words
Apparatus as in claim 1 wherein the light source is formed as a lens lamp having an optical lens thereon.
Claim 9
Dependent Claim
21 words
Apparatus as in claim 1 wherein a forehead support is attached to a housing for said apparatus for testing visual acuity.
Claim 10
Dependent Claim
33 words
Apparatus as in claim 8 wherein the forehead support comprises two parallel, spaced-from-one-another, arms so that there is an opening between the arms to allow a field of vision to the patient's eyes.
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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) | 1998-12-25 | 1999-06-26 | 1999-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-12-25 | 2003-06-26 | 2003-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-12-25 | 2007-06-26 | 2007-12-26 | $7700.00 | Window Closed / Lapsed |