US4987299A
Expired / Lapsed
US
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Rotation quantity measuring method and system
Assignee: Ricoh Co Ltd
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Filing: 1989-08-23
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Granted: 1991-01-22
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Expires: 2009-08-23
Abstract
Abstract A rotation quantity measuring method and system measures a rotation quantity of an object body. The rotation quantity is measured by irradiating a light from a light source on a grating pattern which is formed on a peripheral surface of a cylindrical body which rotates integrally with the object body, and detecting a shadow picture pattern which is generated by a reflected light received from the grating pattern based on a diffraction caused by the grating pattern. Then, the rotation quantity of the object body is measured based on a movement of the shadow picture pattern as the object body rotates.
Inventors
- 👤 Hiroshi Kobayashi
- 👤 Haruhiko Machida
- 👤 Jun Akedo
- 👤 Hiroyoshi Funato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:17
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/42; G01P3/44; G01P3/48; G01P3/481; G01P3/486; G01P3/36; G01P3/366; G02; G02B; G02B5/00; G02B5/18; G02B5/1861
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
138 words
A rotation quantity measuring method for measuring a rotation quantity of an object body, said rotation quantity measuring method comprising the steps of: irradiating a light from a light source on at least one grating pattern which is formed on an outer peripheral surface of a cylindrical body which rotates together with the object body, said grating pattern being made up of gratings which are formed with a constant pitch and which are oriented in a direction which coincides with a rotational direction of said cylindrical body; and detecting a shadow-like diffraction pattern which is generated by a reflected light received from the grating pattern based on a diffraction caused by the grating pattern and measuring the rotation quantity of the object body based on a positional shift of the shadow-like diffraction pattern as the object body rotates.
Claim 2
Dependent Claim
138 words
A rotation quantity measuring method for measuring a rotation quantity of an object body, said rotation quantity measuring method comprising the steps of: irradiating a light from a light source on at least one grating pattern which is formed on an outer peripheral surface of a cylindrical body which rotates together with the object body, said grating pattern being made up of gratings which are formed with a constant pitch and which are oriented in a direction which coincides with a rotational direction of said cylindrical body; and detecting a shadow-like diffraction pattern which is generated by a reflected light received from the grating pattern based on a diffraction caused by the grating pattern and measuring the rotation quantity of the object body based on a positional shift of the shadow-like diffraction pattern as the object body rotates.
Claim 3
Dependent Claim
21 words
The rotation quantity measuring method as claimed in claim 1 wherein said cylindrical body is connected coaxially to said object body.
Claim 4
Dependent Claim
22 words
The rotation quantity measuring method as claimed in claim 1 wherein said cylindrical body is a portion of said object body itself.
Claim 5
Dependent Claim
28 words
The rotation quantity measuring method as claimed in claim 1 wherein said step of irradiating irradiates a coherent light from the light source directly on said grating pattern.
Claim 6
Dependent Claim
33 words
The rotation quantity measuring method as claimed in claim 1 wherein said step of irradiating irradiates on said grating pattern parallel rays which are formed from a light emitted from the light source.
Claim 7
Dependent Claim
45 words
The rotation quantity measuring method as claimed in claim 1 wherein said cylindrical body has a plurality of coded grating patterns formed thereon, and said step of irradiating irradiates a plurality of lights emitted from a plurality of light sources on corresponding coded grating patterns.
Claim 8
Dependent Claim
34 words
The rotation quantity measuring method as claimed in claim 1 wherein said step of detecting detects the reflected light at a position excluding a position where an optical axis of the reflected light passes.
Claim 9
Dependent Claim
56 words
The rotation quantity measuring method as claimed in claim 1 which further comprises the steps of providing a magnetic recording layer on the outer peripheral surface of said cylindrical body, writing a magnetic pattern on said magnetic recording layer, and developing the magnetic pattern by a magnetic colloidal fluid so as to form said grating pattern.
Claim 10
Dependent Claim
31 words
The rotation quantity measuring method as claimed in claim 1 wherein said light source has a finite size which is not negligible compared to said constant pitch of the grating pattern.
Claim 11
Dependent Claim
54 words
The rotation quantity measuring method as claimed in claim 1 wherein said constant pitch of said grating pattern and a size d of said light source along a direction parallel to a direction in which the gratings of said grating pattern are oriented to satisfy a relation (1/10)≦(d/FG)≦2, where PG denotes said constant pitch.
Claim 12
Dependent Claim
142 words
A rotation quantity measuring system for measuring a rotation quantity of an object body, said rotation quantity measuring system comprising: a cylindrical body which rotates together with the object body; at least one grating pattern formed on an outer peripheral surface of said cylindrical body, said grating pattern including gratings which are formed with a constant pitch and which are oriented in a direction which coincides with a rotational direction of said cylindrical body; light source means for emitting light and irradiating the light on said grating pattern; and detecting means for detecting a shadow-like diffraction pattern which is generated by a reflected light received from said grating pattern based on a diffraction caused by said grating pattern and measuring the rotation quantity of the object body based on a positional shift of the shadow-like diffraction pattern as the object body rotates.
Claim 13
Dependent Claim
142 words
A rotation quantity measuring system for measuring a rotation quantity of an object body, said rotation quantity measuring system comprising: a cylindrical body which rotates together with the object body; at least one grating pattern formed on an outer peripheral surface of said cylindrical body, said grating pattern including gratings which are formed with a constant pitch and which are oriented in a direction which coincides with a rotational direction of said cylindrical body; light source means for emitting light and irradiating the light on said grating pattern; and detecting means for detecting a shadow-like diffraction pattern which is generated by a reflected light received from said grating pattern based on a diffraction caused by said grating pattern and measuring the rotation quantity of the object body based on a positional shift of the shadow-like diffraction pattern as the object body rotates.
Claim 14
Dependent Claim
21 words
The rotation quantity measuring system as claimed in claim 11 wherein said cylindrical body is connected coaxially to the object body.
Claim 15
Dependent Claim
22 words
The rotation quantity measuring system as claimed in claim 11 wherein said cylindrical body is a portion of the object body itself.
Claim 16
Dependent Claim
24 words
The rotation quantity measuring system as claimed in claim 11 wherein said light source means irradiates a coherent light directly on said grating pattern.
Claim 17
Dependent Claim
34 words
The rotation quantity measuring system as claimed in claim 11 which further comprises means for irradiating on said grating pattern parallel rays which are formed from the light emitted from said light source means.
Claim 18
Dependent Claim
38 words
The rotation quantity measuring system as claimed in claim 11 wherein said cylindrical body has a plurality of coded grating patterns formed thereon, and said light source means irradiates a plurality of lights on corresponding coded grating patterns.
Claim 19
Dependent Claim
33 words
The rotation quantity measuring system as claimed in claim 11 wherein said detecting means detects the reflected light at a position excluding a position where an optical axis of the reflected light passes.
Claim 20
Dependent Claim
50 words
The rotation quantity measuring system as claimed in claim 11 wherein said grating pattern includes a magnetic recording layer which is formed on the outer peripheral surface of said cylindrical body and a magnetic pattern which is written on said magnetic recording layer and developed by a magnetic colloidal fluid.
Claim 21
Dependent Claim
31 words
The rotation quantity measuring system as claimed in claim 11 wherein said light source has a finite size which is not negligible compared to said constant pitch of the grating pattern.
Claim 22
Dependent Claim
53 words
The rotation quantity measuring system as claimed in claim 11 wherein said constant pitch of said grating pattern and a size d of said light source along a direction parallel to a direction in which the gratings of said grating pattern are oriented satisfy a relation (1/10)≦(d/PG)≦2, where PG denotes said constant pitch.
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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) | 1994-01-21 | 1994-07-23 | 1995-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-21 | 1998-07-23 | 1999-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-21 | 2002-07-23 | 2003-01-22 | $7700.00 | Window Closed / Lapsed |