Patent US3726595A successfully refreshed from Google Patents.
US3726595A
Expired / Lapsed
US
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Method for optical detection and/or measurement of movement of a diffraction grating
Assignee: Canon Inc
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Filing: 1971-01-05
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Granted: 1973-04-10
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Expires: 1991-01-05
Abstract
Abstract A method for optical detection and/or measurement of movement of a diffraction grating which is characterized in that the vertical movement of the diffraction grating in respect to a standard parallel beam is detected based on variation in interference fringes produced by diffracted waves from the grating moving in the standard parallel beams.
Inventors
- 👤 K Matsumoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:40
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/42; G02B27/4233; G02B27/4255
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
101 words
The method of optically detecting movement of a diffaction grating, which comprises orienting a light beam toward an optical apparatus which includes the grating, within the optical apparatus forming interference fringes with light waves from the beam by two steps, said two steps including the step of causing light waves from the beam to diverge from each other and the step of superposing the diverging light waves on each other so as to produce interference between the light waves, one of said steps including diffracting the light waves with said grating, and sensing the change in intensity of the interference fringes.
Claim 2
Independent Claim
101 words
The method of optically detecting movement of a diffaction grating, which comprises orienting a light beam toward an optical apparatus which includes the grating, within the optical apparatus forming interference fringes with light waves from the beam by two steps, said two steps including the step of causing light waves from the beam to diverge from each other and the step of superposing the diverging light waves on each other so as to produce interference between the light waves, one of said steps including diffracting the light waves with said grating, and sensing the change in intensity of the interference fringes.
Claim 3
Dependent Claim
29 words
The method as in claim 1, wherein the step of causing the light waves in the beam to diverge includes the diffracting of the light waves with said grating.
Claim 4
Dependent Claim
29 words
The method as in claim 1, wherein the step of superposing includes directing the diverging light waves into the diffraction grating from different directions and diffracting these light waves.
Claim 5
Dependent Claim
25 words
The method as in claim 1, wherein the other of said steps includes the step of reflecting the waves and passing them through a half-mirror.
Claim 6
Dependent Claim
44 words
The method as in claim 1, wherein the interference fringes are formed by the additional step of focusing the superposed light waves onto a point and, wherein the step of sensing the change in intensity includes measuring the change in intensity of the fringes.
Claim 7
Dependent Claim
30 words
The method as in claim 1, wherein the step of superposing the pair of waves superposes waves of different diffraction orders whose difference in order is not equal to 1.
Claim 8
Dependent Claim
20 words
The method as in claim 1, wherein the waves forming the interference fringes have a symmetrical relationship with each other.
Claim 9
Independent Claim
118 words
The method of determining the straightness of a surface on an object, which comprises holding a diffraction grating transverse to the surface and moving the grating along the surface, orienting a light beam at an optical apparatus which includes the grating, within the optical apparatus forming interference fringes with light waves from the beam by two steps, said two steps including the step of causing light waves from the beam to diverge from each other and the step of superposing the diverging light waves on each other so as to produce interference between the light waves, one of said steps including diffracting the light waves with said grating, and sensing the change in intensity of the interference fringes.
Claim 10
Independent Claim
118 words
The method of determining the straightness of a surface on an object, which comprises holding a diffraction grating transverse to the surface and moving the grating along the surface, orienting a light beam at an optical apparatus which includes the grating, within the optical apparatus forming interference fringes with light waves from the beam by two steps, said two steps including the step of causing light waves from the beam to diverge from each other and the step of superposing the diverging light waves on each other so as to produce interference between the light waves, one of said steps including diffracting the light waves with said grating, and sensing the change in intensity of the interference fringes.
Claim 11
Dependent Claim
29 words
A method as in claim 8, wherein the step of causing the light waves in the beam to diverge includes the diffracting of the light waves with said grating.
Claim 12
Dependent Claim
29 words
The method as in claim 8, wherein the step of superposing includes directing the diverging light waves into the diffraction grating from different directions and diffracting these light waves.
Claim 13
Dependent Claim
25 words
The method as in claim 8, wherein the other of said steps includes the step of reflecting the waves and passing them through a half-mirror.
Claim 14
Dependent Claim
44 words
The method as in claim 8, wherein the interference fringes are formed by the additional step of focusing the superposed light waves onto a point and, wherein the step of sensing the change in intensity includes measuring the change in intensity of the fringes.
Claim 15
Independent Claim
99 words
An apparatus for determining the movement of a grating, comprising orienting means for orienting a light beam toward the grating, interference fringe forming means for interacting with the grating and producing interference fringes, said fringe forming means including first light controlling means for causing light waves from the beam to diverge from each other and second light controlling means for superposing the diverging light waves on each other so as to produce interference between the light waves, one of said light controlling means including the diffraction grating, and means for sensing the change in intensity of the interference fringes.
Claim 16
Independent Claim
99 words
An apparatus for determining the movement of a grating, comprising orienting means for orienting a light beam toward the grating, interference fringe forming means for interacting with the grating and producing interference fringes, said fringe forming means including first light controlling means for causing light waves from the beam to diverge from each other and second light controlling means for superposing the diverging light waves on each other so as to produce interference between the light waves, one of said light controlling means including the diffraction grating, and means for sensing the change in intensity of the interference fringes.
Claim 17
Dependent Claim
28 words
An apparatus as in claim 13, wherein said fringe forming means includes focusing means and forms a focusing plane, said focusing means focusing the fringes on the plane.
Claim 18
Dependent Claim
20 words
An apparatus as in claim 13, wherein said sensing means includes means for measuring the intensity of the interference fringes.
Claim 19
Independent Claim
102 words
An apparatus for determining the straightness of a surface, comprising a diffraction grating, orienting means for orienting a light beam toward the grating, interference fringe forming means for interacting with the grating and producing interference fringes, said fringe forming means including first light controlling means for causing light waves from the beam to diverge from each other and second light controlling means for superposing the diverging light waves on each other so as to produce interference between the light waves, one of said light controlling means including the diffraction grating, and means for sensing the change in intensity of the interference fringes.
Claim 20
Independent Claim
102 words
An apparatus for determining the straightness of a surface, comprising a diffraction grating, orienting means for orienting a light beam toward the grating, interference fringe forming means for interacting with the grating and producing interference fringes, said fringe forming means including first light controlling means for causing light waves from the beam to diverge from each other and second light controlling means for superposing the diverging light waves on each other so as to produce interference between the light waves, one of said light controlling means including the diffraction grating, and means for sensing the change in intensity of the interference fringes.
Claim 21
Dependent Claim
28 words
An apparatus as in claim 16, wherein said fringe forming means includes focusing means and forms a focusing plane, said focusing means focusing the fringes on the plane.
Claim 22
Dependent Claim
20 words
An apparatus as in claim 16, wherein said sensing means includes means for measuring the intensity of the interference fringes.
References Cited (Backward Citations)
US2745310A
Cited
US3169193A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |