Patent US3574464A successfully refreshed from Google Patents.
US3574464A
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US
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Camera test equipment and method
Assignee: Individual
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Filing: 1968-07-16
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Granted: 1971-04-13
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Expires: 1988-07-16
Abstract
Abstract Two methods are described for testing cameras and camera lenses by utilizing the properties of the crossed-cylinder lens, an ophthalmic test device. In the first, the cylinder lens is used in conjunction with a rectangular grid to defocus the star image formed by a collimator. This test permits quantitative determination of axial chromatic aberration, spherical aberration and its variations with wavelength, and coma of the lens. In the second, a segment of the cylinder lens is used as a supplementary lens attachment to the camera, which photographs a polarcoordinate chart. Analysis of the photograph permits determination of the sagittal and tangential field curvatures and also indicates errors in focal adjustment and misalignment of film plane with respect to the lens axis. These tests require cylinder lenses of smaller dioptric power and quality superior to that available from the ophthalmic lens industry. Methods for the construction and synthesis of the needed large-aperture weak, cross-cylinder lenses and segments are given.
Inventors
- 👤 Bradford Howland
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:14
CPC Classifications
G; G01; G01M; G01M11/00; G01M11/02; G01M11/0242; G01M11/0257; G01M11/0264; G01M11/0221; G01M11/0285
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
140 words
For testing a camera having an objective by imaging a test image upon a film, apparatus in combination comprising: a. means for positioning said image with respect to said objective so that a picture of said image may be made on said film; b. an astigmator, having a power no more than 2 1/2 percent of the power of said objective; c. means for positioning said astigmator between said objective and said image so that in concert with said objecTive astigmatic foci are located one in front of, and one behind said film; and d. a rectilinear obstacle, positioned closely in front of said objective to block a portion of the light entering said objective from said image, with a principal linear element of said obstacle aligned parallel to the bisector of the principal axes of correction of said astigmator.
Claim 2
Dependent Claim
140 words
For testing a camera having an objective by imaging a test image upon a film, apparatus in combination comprising: a. means for positioning said image with respect to said objective so that a picture of said image may be made on said film; b. an astigmator, having a power no more than 2 1/2 percent of the power of said objective; c. means for positioning said astigmator between said objective and said image so that in concert with said objecTive astigmatic foci are located one in front of, and one behind said film; and d. a rectilinear obstacle, positioned closely in front of said objective to block a portion of the light entering said objective from said image, with a principal linear element of said obstacle aligned parallel to the bisector of the principal axes of correction of said astigmator.
Claim 3
Dependent Claim
38 words
Apparatus as defined by claim 1: e. wherein said test image is a polar-coordinate chart having lines of equal thickness; f. wherein said astigmator is a crossed-cylinder lens; and g. said obstacle has a straight diametric slit therethrough.
Claim 4
Dependent Claim
12 words
a negative cylinder lens between said collimating lens and said source; and
Claim 5
Dependent Claim
12 words
a negative cylinder lens between said collimating lens and said source; and
Claim 6
Dependent Claim
21 words
means for adjusting the spacing between said source and said cylinder lens and between said cylinder lens and said collimating lens.
Claim 7
Dependent Claim
21 words
means for adjusting the spacing between said source and said cylinder lens and between said cylinder lens and said collimating lens.
Claim 8
Dependent Claim
23 words
Apparatus as defined by claim 2: h. wherein said chart has equally spaced concentric circles and evenly spaced radial lines of equal thickness.
Claim 9
Dependent Claim
21 words
Apparatus as defined by claim 2 (h) wherein said obstacle is an opaque coating of said lens divided by said slit.
Claim 10
Dependent Claim
26 words
Apparatus as defined by claim 1: e. wherein said test image is a polar-coordinate chart; and f. said astigmator is a segment of a crossed-cylinder lens.
Claim 11
Dependent Claim
23 words
Apparatus as defined by claim 1: g. wherein said object is a simulated star; and h. wherein said obstacle is a rectangular screen.
Claim 12
Dependent Claim
30 words
Apparatus as defined by claim 6: i. wherein said star is simulated by a virtual source which is the image of a selected illuminated aperture, reduced by a microscope lens.
Claim 13
Dependent Claim
11 words
Apparatus as defined by claim 7: j. wherein said astigmator comprises:
Claim 14
Independent Claim
136 words
The method of testing a camera range-finder and objective lens comprising the steps of: a. placing a target comprising a pattern of contrasting radial lines of uniform thickness centered in the field of said camera normal to its optical axis at a distance determined by said range-finder; b. interposing closely in front of said lens and coaxially, and analyzer comprising a lens element bounded by surfaces defined by a plane and a twisting sheet, and a slit limiting transmission to a section including the line of uniform thickness through said element; c. forming by photographic exposure through said analyzer and lens an image of lines of said pattern on a photosensitive medium in said camera; d. developing said image to high contrast; and e. noting the lines of said pattern which are reproduced in said steps.
Claim 15
Independent Claim
136 words
The method of testing a camera range-finder and objective lens comprising the steps of: a. placing a target comprising a pattern of contrasting radial lines of uniform thickness centered in the field of said camera normal to its optical axis at a distance determined by said range-finder; b. interposing closely in front of said lens and coaxially, and analyzer comprising a lens element bounded by surfaces defined by a plane and a twisting sheet, and a slit limiting transmission to a section including the line of uniform thickness through said element; c. forming by photographic exposure through said analyzer and lens an image of lines of said pattern on a photosensitive medium in said camera; d. developing said image to high contrast; and e. noting the lines of said pattern which are reproduced in said steps.
References Cited (Backward Citations)
US3100239A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-12 | 1974-10-12 | 1975-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-12 | 1978-10-12 | 1979-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-12 | 1982-10-12 | 1983-04-13 | $7700.00 | Window Closed / Lapsed |