US4609287A
Expired / Lapsed
US
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Method of and apparatus for measuring refractive characteristics
Assignee: Canon Inc
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Filing: 1983-06-10
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Granted: 1986-09-02
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Expires: 2003-06-10
Abstract
Abstract At least three light beams are applied to different positions on an optical element to be measured. The light beams coming via the optical element to be measured are received through a light-receiving lens by a two-dimensional light position detecting system provided at the rearward focus position of the light-receiving lens or at a position conjugate therewith or are received by two-dimensionally disposed light position detecting system. Three deviation vectors are detected and the refractive powers in three meridian directions are detected, or at least five light beams are applied to different positions on an optical element to be measured and from five deviated beam positions, a general elliptical curve coupling them is specified, whereby the degree of astigmatism, the direction of astigmatism and the refractive power are calculated.
Inventors
- 👤 Yoshimi Kohayakawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:02
CPC Classifications
G; G01; G01M; G01M11/00; G01M11/02; G01M11/0242; G01M11/0257; G01M11/0264; G01M11/005; G01M11/0228; G01M11/0235
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
108 words
A method of measuring refractive characteristics of an optical element to be measured, said method comprising the steps of: applying at least three light beams to different positions on the optical element to be measured, receiving the light beams coming via said optical element to be measured by a light position detecting element and detecting at least three deviation vectors indicative of the degrees of deviation of said light beams; calculating the refractive characteristics in at least three predetermined meridian directions from said deviation vectors; and specifying the degree of astigmatism, the direction of astigmatism and the refractive power from the refractive characteristics in said three meridian directions.
Claim 2
Independent Claim
108 words
A method of measuring refractive characteristics of an optical element to be measured, said method comprising the steps of: applying at least three light beams to different positions on the optical element to be measured, receiving the light beams coming via said optical element to be measured by a light position detecting element and detecting at least three deviation vectors indicative of the degrees of deviation of said light beams; calculating the refractive characteristics in at least three predetermined meridian directions from said deviation vectors; and specifying the degree of astigmatism, the direction of astigmatism and the refractive power from the refractive characteristics in said three meridian directions.
Claim 3
Dependent Claim
36 words
A method according to claim 1, further comprising the step of effecting alignment by making the vector sum of said deviation vectors zero and calculating the refractive characteristics in the three meridian directions after said alignment.
Claim 4
Dependent Claim
34 words
A method according to claim 1, wherein the light beams are successively applied to three points on a circumference centered at a point on the optical axis of said optical element to be measured.
Claim 5
Independent Claim
122 words
An apparatus for measuring refractive characteristics of an optical element to be measured, said apparatus comprising: means for applying at least three light beams to different positions on the optical element to be measured; a light-receiving imaging system for receiving the light-beams passed through said optical element to be measured; light position detecting means provided at the focus position of said light-receiving imaging system; and means for finding the refractive characteristics of the optical element to be measured in three predetermined meridian directions from at least three deviation vectors determined by said light position detecting means and indicative of the degrees of deviation of said light beams, and calculating the degree of astigmatism, the direction of astigmatism and the refractive power therefrom.
Claim 6
Independent Claim
122 words
An apparatus for measuring refractive characteristics of an optical element to be measured, said apparatus comprising: means for applying at least three light beams to different positions on the optical element to be measured; a light-receiving imaging system for receiving the light-beams passed through said optical element to be measured; light position detecting means provided at the focus position of said light-receiving imaging system; and means for finding the refractive characteristics of the optical element to be measured in three predetermined meridian directions from at least three deviation vectors determined by said light position detecting means and indicative of the degrees of deviation of said light beams, and calculating the degree of astigmatism, the direction of astigmatism and the refractive power therefrom.
Claim 7
Dependent Claim
21 words
An apparatus according to claim 4, further having means for condensing said light beams on said optical element to be measured.
Claim 8
Dependent Claim
19 words
An apparatus according to claim 4, wherein said light position detecting means is a two-dimensional light position detecting element.
Claim 9
Dependent Claim
58 words
An apparatus according to claim 4, wherein said light position detecting means comprises a plural-division element and means defining a predetermined aperture through which light beams from said applying means are applied to said optical element to be measured, and wherein the degree of deviation of the light beams from said aperture on said plural-division element is detected.
Claim 10
Dependent Claim
78 words
An apparatus according to claim 4, wherein said light position detecting means comprises two one-dimensional detecting elements orthogonal to each other and means defining two slit openings through which light beams from said applying means are applied to said optical element to be measured, said slit openings being parallel to said detecting elements and orthogonal to each other, and wherein the degrees of deviation of the images of said slit openings on said one-dimensional detecting elements, is detected.
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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) | 1989-09-01 | 1990-03-03 | 1990-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-01 | 1994-03-03 | 1994-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-01 | 1998-03-03 | 1998-09-02 | $7700.00 | Window Closed / Lapsed |