US3900264A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electro-optical step marker
Assignee: Ernst Leitz Wetzlar GmbH
•
Filing: 1973-06-19
•
Granted: 1975-08-19
•
Expires: 1993-06-19
Abstract
Abstract In an interferometric electro-optical step marker comprising a code trace constructed like a diffraction grating the diffraction orders are caused to interfere with one another in pairs in order to generate periodically varying measurement signals. The diffraction grating is so constructed that as a consequence of its line pattern at least one diffraction order of a higher number, preferably > OR = 3, receives clearly more light in comparison to the remaining diffraction orders. The combination of such diffraction orders with higher numbers results in a higher Doppler frequency, whereby the mechanically ruled grating interval is electro-optically subdivided.
Inventors
- 👤 Knut Heitmann
- 👤 Eckart Schneider
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:57
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/36; G01D5/38
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
139 words
In an apparatus having a diffraction grating suitable for measuring a property of movement of said grating relative to a beam of radiation with reference to at least one coordinate axis and defining at least one set of two diffraction orders, means to cause radiation of one of the diffraction orders of one set to interfere with the radiations of the other one of the diffraction orders of the respective set, and detecting means receiving the radiation of said interfering diffraction orders and generating electric signals indicative of the property of movement, the improvement comprising: said diffraction grating having a uniform line geometry and a plurality of sections with groove geometry varied irregularly by section defining at least one set of two diffraction orders other than the zero diffraction order and energetically preferred to all the other diffraction orders.
Claim 2
Dependent Claim
139 words
In an apparatus having a diffraction grating suitable for measuring a property of movement of said grating relative to a beam of radiation with reference to at least one coordinate axis and defining at least one set of two diffraction orders, means to cause radiation of one of the diffraction orders of one set to interfere with the radiations of the other one of the diffraction orders of the respective set, and detecting means receiving the radiation of said interfering diffraction orders and generating electric signals indicative of the property of movement, the improvement comprising: said diffraction grating having a uniform line geometry and a plurality of sections with groove geometry varied irregularly by section defining at least one set of two diffraction orders other than the zero diffraction order and energetically preferred to all the other diffraction orders.
Claim 3
Dependent Claim
28 words
Apparatus as claimed in claim 1, wherein the modulus of each of the two order numbers of one set of diffraction orders is at least equal to 3.
Claim 4
Dependent Claim
26 words
Apparatus as claimed in claim 1, wherein the order numbers of the two diffraction orders of one set have the same modulus and mutually opposite sign.
Claim 5
Dependent Claim
115 words
Apparatus including a diffraction grating comprising a plurality of pyramidal diffracting elements suitable for measuring a property of movement of the grating relative to a beam of radiation with reference to at least one coordinate Axis, the grating defining at least one set of two diffraction orders other than the zero diffraction order, which are energetically preferred to other diffraction orders, wherein the improvement comprises: a. means for causing radiation of one of the diffraction orders of one set to interfere with radiation of the other one of the diffraction orders of the respective set; and b. detecting means to receive said interfering radiation and to generate electric signals indicative of the property of movement.
Claim 6
Dependent Claim
115 words
Apparatus including a diffraction grating comprising a plurality of pyramidal diffracting elements suitable for measuring a property of movement of the grating relative to a beam of radiation with reference to at least one coordinate Axis, the grating defining at least one set of two diffraction orders other than the zero diffraction order, which are energetically preferred to other diffraction orders, wherein the improvement comprises: a. means for causing radiation of one of the diffraction orders of one set to interfere with radiation of the other one of the diffraction orders of the respective set; and b. detecting means to receive said interfering radiation and to generate electric signals indicative of the property of movement.
Claim 7
Dependent Claim
64 words
Apparatus as claimed in claim 4, wherein the grating defines at least one individual set of two preferred diffraction orders associated with each respective one of a plurality of co-ordinate axes, the order numbers of the preferred diffraction orders associated with each individual co-ordinate axis being different from the order numbers of the diffraction orders associated with the or each respective other co-ordinate axis.
Claim 8
Dependent Claim
166 words
In an apparatus having a diffraction grating suitable for measuring a property of movement of said grating relative to a beam of radiation with reference to at least one coordinate axis and defining at least one set of two diffraction orders, means to cause radiation of one of the diffraction orders of one set to interfere with the radiations of the other one of the diffraction orders of the respective set, and detecting means receiving the radiation of said interfering diffraction orders and generating electric signals indicative of the property of movement, the improvement comprising: said diffraction grating having a line geometry defining at least one set of two diffraction orders other than the zero diffraction order and energetically preferred to all the other diffraction orders, said diffraction grating having a uniform grating constant over the whole of the surface of said grating, individual portions of said surface of said grating defining respectively different sets of two preferred diffraction orders associated with the same coordinate axis.
Claim 9
Dependent Claim
166 words
In an apparatus having a diffraction grating suitable for measuring a property of movement of said grating relative to a beam of radiation with reference to at least one coordinate axis and defining at least one set of two diffraction orders, means to cause radiation of one of the diffraction orders of one set to interfere with the radiations of the other one of the diffraction orders of the respective set, and detecting means receiving the radiation of said interfering diffraction orders and generating electric signals indicative of the property of movement, the improvement comprising: said diffraction grating having a line geometry defining at least one set of two diffraction orders other than the zero diffraction order and energetically preferred to all the other diffraction orders, said diffraction grating having a uniform grating constant over the whole of the surface of said grating, individual portions of said surface of said grating defining respectively different sets of two preferred diffraction orders associated with the same coordinate axis.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-18 | 1979-02-17 | 1979-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-18 | 1983-02-17 | 1983-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-18 | 1987-02-17 | 1987-08-19 | $7700.00 | Window Closed / Lapsed |