Patent US4274715A successfully refreshed from Google Patents.
US4274715A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for the projection of optical test objects
Assignee: Schwind Eye Tech Solutions GmbH
•
Filing: 1979-03-30
•
Granted: 1981-06-23
•
Expires: 1999-03-30
Abstract
Abstract Method and apparatus for projecting or imaging optotypes so that they can be perceived in space under conditions of unimpeded vision without requiring, e.g., projection screens.
Inventors
- 👤 Josef Reiner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:18
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/12
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
131 words
An apparatus for the projection of optotypes for use in the subjective determination of eye refraction, the apparatus comprising: a. a housing; b. a collimator disposed within the housing; c. means disposed within the housing the forming illuminated optotypes at the object focal plane of the collimator; and d. means coactive with the eye under examination and receptive of the image from the collimator for projecting same into free space in a line of sight defined by the eye and the projected image which is outside of said housing, the projecting means comprising means defining an output aperture in the housing through which the collimator image passes and a beam splitter mirror outisde of the housing and in said line of sight and receptive of the collimator image through the aperture.
Claim 2
Independent Claim
131 words
An apparatus for the projection of optotypes for use in the subjective determination of eye refraction, the apparatus comprising: a. a housing; b. a collimator disposed within the housing; c. means disposed within the housing the forming illuminated optotypes at the object focal plane of the collimator; and d. means coactive with the eye under examination and receptive of the image from the collimator for projecting same into free space in a line of sight defined by the eye and the projected image which is outside of said housing, the projecting means comprising means defining an output aperture in the housing through which the collimator image passes and a beam splitter mirror outisde of the housing and in said line of sight and receptive of the collimator image through the aperture.
Claim 3
Dependent Claim
27 words
The apparatus according to claim 1, wherein the beam splitter mirror is disposed at an angle of 45° with respect to the optical axis of the collimator.
Claim 4
Dependent Claim
25 words
The apparatus according to claim 1 or claim 2, wherein the collimator and beam splitter mirror are configured to permit binocular vision of the optotypes.
Claim 5
Dependent Claim
29 words
The apparatus according to claim 3, wherein the collimator comprises a concave reflector and further comprising a second beam splitter mirror for projecting the optotype image on the reflector.
Claim 6
Independent Claim
110 words
A method for projecting optotypes for the subjective determination of eye refraction, the method comprising the steps of: a. providing a housing and a collimator therein; b. illuminating optotypes within the housing and at the object focal plane of the collimator; and c. projecting the image from the collimator into free space in a line of sight between the eye under examination and the projected image which is outside of said housing by providing an output aperture in the housing through which the collimator image passes and providing a beam splitter mirror outside of the housing in said line of sight and receptive of the collimator image through the aperture.
Claim 7
Independent Claim
110 words
A method for projecting optotypes for the subjective determination of eye refraction, the method comprising the steps of: a. providing a housing and a collimator therein; b. illuminating optotypes within the housing and at the object focal plane of the collimator; and c. projecting the image from the collimator into free space in a line of sight between the eye under examination and the projected image which is outside of said housing by providing an output aperture in the housing through which the collimator image passes and providing a beam splitter mirror outside of the housing in said line of sight and receptive of the collimator image through the aperture.
References Cited (Backward Citations)
US2212597A
Cited
GB690966A
Cited
DE1016462B
Cited
DE1962698U
Cited
DE1955859U
Cited
US3524702A
Cited
US3572910A
Cited
DE2042109A1
Cited
US3737217A
Cited
DE2543903B2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-06-22 | 1984-12-22 | 1985-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-22 | 1988-12-22 | 1989-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-22 | 1992-12-22 | 1993-06-23 | $7700.00 | Window Closed / Lapsed |