US4967072A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Interferometric rotating condition detection apparatus
Assignee: Canon Inc
•
Filing: 1990-02-20
•
Granted: 1990-10-30
•
Expires: 2010-02-20
Abstract
Abstract A rotating condition detection apparatus includes a light source for illuminating a radial lattice having a plurality of lattice patterns marked on a periphery of a rotating body at an equi-angle; an optical unit for superimposing two refraction lights having a predetermined number of order reflected in two predetermined directions by the radial lattice; a photosensing device for sensing the superimposed light; and a detector for detecting a rotating condition of the rotating body in accordance with the output of the photosensing means.
Inventors
- 👤 Tetsuharu Nishimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:04
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/36; G01D5/38; G01P; G01P13/00; G01P13/02; G01P13/04; G01P13/045; G01P3/00; G01P3/36; G01P3/366
Claims Analysis
Total Claims: 58
Claim 1
Independent Claim
90 words
A rotating condition detection apparatus, comprising: optical means for directing a laser beam to a diffraction grating formed on a rotating body along a rotary direction thereof, said optical means linearly illuminating said diffraction grating with said laser beam in a direction of said rotating body; light receiving means for photoelectrically converting an interference light formed by diffracted lights of predetermined orders emitting from said diffraction grating; and detecting means for detecting a rotating condition of the rotating body on the basis of a signal from said light receiving means.
Claim 2
Dependent Claim
90 words
A rotating condition detection apparatus, comprising: optical means for directing a laser beam to a diffraction grating formed on a rotating body along a rotary direction thereof, said optical means linearly illuminating said diffraction grating with said laser beam in a direction of said rotating body; light receiving means for photoelectrically converting an interference light formed by diffracted lights of predetermined orders emitting from said diffraction grating; and detecting means for detecting a rotating condition of the rotating body on the basis of a signal from said light receiving means.
Claim 3
Dependent Claim
24 words
A rotating condition detecting apparatus according to claim 1 wherein said detecting means comprises means for counting the rotational speed of the rotating body.
Claim 4
Dependent Claim
24 words
A rotating condition detection apparatus according to claim 2, wherein said detecting means comprises means for discriminating a rotational direction of the rotating body.
Claim 5
Dependent Claim
137 words
A rotating condition detection apparatus, comprising: first optical means for directing a laser beam to a first position of a diffraction grating formed on a rotating body along a rotary direction thereof; second optical means for projecting diffracted lights of ±m-order emitting from said first position to a second position of said diffraction grating different from said first position and making a re-diffracted light of ±m-order obtained by diffracting said diffracted light of ±m-order and a re-diffracted light of -m-order obtained by diffracting said diffracted light of -m-order emitted from said second position in substantially the same direction; light receiving means for photoelectrically converting an interference light formed by said re-diffracted lights of ±m-order; and detecting means for detecting a rotating condition of the rotating body on the basis of a signal from said light receiving means.
Claim 6
Dependent Claim
137 words
A rotating condition detection apparatus, comprising: first optical means for directing a laser beam to a first position of a diffraction grating formed on a rotating body along a rotary direction thereof; second optical means for projecting diffracted lights of ±m-order emitting from said first position to a second position of said diffraction grating different from said first position and making a re-diffracted light of ±m-order obtained by diffracting said diffracted light of ±m-order and a re-diffracted light of -m-order obtained by diffracting said diffracted light of -m-order emitted from said second position in substantially the same direction; light receiving means for photoelectrically converting an interference light formed by said re-diffracted lights of ±m-order; and detecting means for detecting a rotating condition of the rotating body on the basis of a signal from said light receiving means.
Claim 7
Dependent Claim
42 words
A rotating condition detection apparatus according to claim 4, wherein the distance between said first position and the rotational center of the rotating body is approximately equal to the distance between said second position and the rotational center of the rotating body.
Claim 8
Dependent Claim
30 words
A rotating condition detection apparatus according to claim 5, wherein the rotational center of the rotating body is on a line extending from said first position to said second position.
Claim 9
Independent Claim
82 words
A method for detecting a rotating condition of a rotating body having a diffraction grating marked along a rotating direction thereof, said method comprising the steps of; linearly illuminating said diffraction grating in a direction substantially perpendicular to a radial direction of said rotating body with a predetermined laser beam; and photoelectrically converting an interference light obtained by superimposing diffraction lights, created at the diffraction grating, having respective predetermined order numbers so as to detect the rotating condition of the rotating body.
Claim 10
Independent Claim
82 words
A method for detecting a rotating condition of a rotating body having a diffraction grating marked along a rotating direction thereof, said method comprising the steps of; linearly illuminating said diffraction grating in a direction substantially perpendicular to a radial direction of said rotating body with a predetermined laser beam; and photoelectrically converting an interference light obtained by superimposing diffraction lights, created at the diffraction grating, having respective predetermined order numbers so as to detect the rotating condition of the rotating body.
Claim 11
Dependent Claim
30 words
A method according to claim 7 wherein said illuminating step includes a step of preparing a laser, and a step of directing light from the laser to a cylindrical lens.
Claim 12
Dependent Claim
47 words
A method according to claim 8 wherein said illuminating step further includes a step of re-directing the diffraction lights created at the diffraction grating back to the diffraction grating, and the superimposed diffraction lights in said converting step are those which are re-diffracted by the diffraction grating.
Claim 13
Dependent Claim
19 words
A method according to claim 9 wherein said illuminating step is conducted by using a single linear coherent light.
Claim 14
Dependent Claim
33 words
A method according to claim 10 wherein the position of the diffraction grating to which each of the diffraction lights is re-directed is different from a position where said diffraction lights are created.
Claim 15
Dependent Claim
32 words
A method according to claim 10 wherein the position of the diffraction grating to which each of the diffraction lights is re-directed in the same position where said diffraction lights are created.
Claim 16
Dependent Claim
32 words
A method according to claim 7 wherein the amount of rotation or the speed of rotation of the rotating body is detected based on a signal obtained in said photoelectric converting step.
Claim 17
Dependent Claim
53 words
A method according to claim 4 wherein said illuminating step includes a step of preparing a laser, a step of dividing light from the laser into two light beams and a step of directing said two light beams to respective cylindrical lenses, and the diffraction grating is irradiated with two linear coherent lights.
Claim 18
Independent Claim
118 words
A method for detecting a rotating condition of a rotating body having a rotational center and a diffraction grating marked along a rotating direction thereof, said method comprising the steps of: directing a laser beam to a first position of the diffraction grating; projecting diffracted lights of ±m-order emitting from said first position to a second position of said diffraction grating different from said first position and making a re-diffracted light of ±m-order obtained by diffracting said diffracted light of ±m-order and a re-diffracted light of -m-order obtained by diffracting said diffracted light of -m-order emitted from said second position in substantially the same direction; and photoelectrically converting an interference light formed by said re-diffracted lights of ±m-order.
Claim 19
Independent Claim
118 words
A method for detecting a rotating condition of a rotating body having a rotational center and a diffraction grating marked along a rotating direction thereof, said method comprising the steps of: directing a laser beam to a first position of the diffraction grating; projecting diffracted lights of ±m-order emitting from said first position to a second position of said diffraction grating different from said first position and making a re-diffracted light of ±m-order obtained by diffracting said diffracted light of ±m-order and a re-diffracted light of -m-order obtained by diffracting said diffracted light of -m-order emitted from said second position in substantially the same direction; and photoelectrically converting an interference light formed by said re-diffracted lights of ±m-order.
Claim 20
Dependent Claim
27 words
A method according to claim 15 wherein the rotational center of the rotating body is on an axis extending from said first position to said second position.
Claim 21
Dependent Claim
39 words
A method according to claim 16 wherein the distance between said first position and the rotational center of the rotating body is substantially equal to the distance between said second position and the rotational center of the rotating body.
Claim 22
Dependent Claim
26 words
A method according to claim 17 wherein said projection step is performed through an optical system which makes said first position conjugate with said second position.
Claim 23
Dependent Claim
21 words
A method according to claim 15 wherein all of said first and second re-diffracted lights of ±m-order are reflected diffraction lights.
Claim 24
Dependent Claim
54 words
A method according to claim 15 wherein said directing step includes a step of preparing a laser and a step of directing light from said laser to a cylindrical lens, and said diffraction grating is linearly illuminated in a direction substantially perpendicular to a radial direction of said rotating body with said light beam.
Claim 25
Dependent Claim
32 words
A method according to claim 15 wherein the amount of rotation or the speed of rotation of the rotating body is detected based on a signal obtained in said photoelectric converting step.
Claim 26
Independent Claim
115 words
A method for detecting a rotating condition of a rotating body having a rotational center and a diffraction grating marked along a rotating direction thereof, said method comprising the steps of: directing a laser beam to a first position of the diffraction grating; projecting first and second diffraction lights, created at said first position, having respective predetermined order numbers onto a second position of the diffraction grating through an optical system which makes said first position conjugates with said second position; and photoelectrically converting an interference light obtained by superimposing third and fourth diffraction lights created at said second position of the diffraction grating so as to detect the rotating condition of the rotating body.
Claim 27
Independent Claim
115 words
A method for detecting a rotating condition of a rotating body having a rotational center and a diffraction grating marked along a rotating direction thereof, said method comprising the steps of: directing a laser beam to a first position of the diffraction grating; projecting first and second diffraction lights, created at said first position, having respective predetermined order numbers onto a second position of the diffraction grating through an optical system which makes said first position conjugates with said second position; and photoelectrically converting an interference light obtained by superimposing third and fourth diffraction lights created at said second position of the diffraction grating so as to detect the rotating condition of the rotating body.
Claim 28
Dependent Claim
15 words
A method according to claim 22 wherein said first and second positions are the same.
Claim 29
Independent Claim
55 words
A method according to cl aim 23 wherein said directing step includes a step of preparing a laser and a step of directing light from said laser to a cylindrical lens, and said first position is linearly illuminated in a direction substantially perpendicular to a radial direction of said rotating body with the light beam.
Claim 30
Independent Claim
55 words
A method according to cl aim 23 wherein said directing step includes a step of preparing a laser and a step of directing light from said laser to a cylindrical lens, and said first position is linearly illuminated in a direction substantially perpendicular to a radial direction of said rotating body with the light beam.
Claim 31
Independent Claim
25 words
A method according to cl aim 22 wherein said first position is symmetrical with said second position about the rotational center of the rotating body.
Claim 32
Independent Claim
25 words
A method according to cl aim 22 wherein said first position is symmetrical with said second position about the rotational center of the rotating body.
Claim 33
Dependent Claim
54 words
A method according to claim 25 wherein said directing step includes a step of preparing a laser and a step of directing light from said laser to a cylindrical lens, and said first position is linearly illuminated in a direction substantially perpendicular to a radial direction of said rotating body with the light beam.
Claim 34
Dependent Claim
31 words
A method according to claim 22 wherein the amount of rotation or the speed of rotation of the rotating body is detected based on a signal obtained in said photoelectric step.
Claim 35
Independent Claim
126 words
A method for detecting a rotating condition of a rotating body comprising the steps of: forming a diffraction grating on the rotating body along a rotational direction of the rotating body, directing a laser beam to the diffraction grating; re-directing first and second diffracted lights emitting from said diffraction grating to said diffraction grating through an optical means, said optical means being formed so that emitting positions of said first and second diffracted lights emitting from said diffraction grating and entering positions of said first and second diffracted lights entering into said diffraction grating are conjugate; and photoelectrically converting an interference light obtained by superimposing third and fourth diffraction lights created in said re-directing step so as to detect the rotating condition of the rotating body.
Claim 36
Independent Claim
126 words
A method for detecting a rotating condition of a rotating body comprising the steps of: forming a diffraction grating on the rotating body along a rotational direction of the rotating body, directing a laser beam to the diffraction grating; re-directing first and second diffracted lights emitting from said diffraction grating to said diffraction grating through an optical means, said optical means being formed so that emitting positions of said first and second diffracted lights emitting from said diffraction grating and entering positions of said first and second diffracted lights entering into said diffraction grating are conjugate; and photoelectrically converting an interference light obtained by superimposing third and fourth diffraction lights created in said re-directing step so as to detect the rotating condition of the rotating body.
Claim 37
Dependent Claim
30 words
A method according to claim 28 wherein said re-directing step is performed through first and second reflection optical systems provided and corresponding to said first and second diffraction lights, respectively.
Claim 38
Dependent Claim
32 words
A method according to claim 28 wherein the amount of rotation or the speed of rotation of the rotating body is detected based on a signal obtained in said photoelectric converting step.
Claim 39
Dependent Claim
17 words
A method according to claim 19, wherein the orders of said diffracted and re-diffracted lights are ±1.
Claim 40
Dependent Claim
34 words
A method according to claim 28, wherein said diffraction grating is linearly illuminated in a direction substantially perpendicular to a radial direction of said rotating body with said light beam in said directing step.
Claim 41
Independent Claim
85 words
A method for detecting a rotating state of a rotating body on which a diffraction grating is formed along a rotary direction thereof, comprising the steps of: linearly illuminating the diffraction grating with a radiation beam emitted in a direction substantially perpendicular to a radial direction of the rotating body; forming an interference light beam by superimposing first and second diffracted light beams created at the diffraction grating; and detecting the rotating state of the rotating body on the basis of the interference light beam.
Claim 42
Independent Claim
85 words
A method for detecting a rotating state of a rotating body on which a diffraction grating is formed along a rotary direction thereof, comprising the steps of: linearly illuminating the diffraction grating with a radiation beam emitted in a direction substantially perpendicular to a radial direction of the rotating body; forming an interference light beam by superimposing first and second diffracted light beams created at the diffraction grating; and detecting the rotating state of the rotating body on the basis of the interference light beam.
Claim 43
Independent Claim
122 words
A method for detecting a rotating state of a rotating body on which a diffraction grating is formed along a rotary direction thereof, comprising the steps of: illuminating a predetermined position of the diffraction grating with a laser beam; directing diffracted light beams of ±m-order created at the predetermined position to another position of the diffraction grating different from the predetermined position; forming an interference light beam by superimposing a rediffracted light beam of ±m-order produced by diffracting the diffracted light beam of ±m-order and a rediffracted light beam of -m-order produced by diffracting the diffracted light beam of -m-order emitting from the another position; and detecting the rotating state of the rotating body on the basis of the interference light beam.
Claim 44
Independent Claim
122 words
A method for detecting a rotating state of a rotating body on which a diffraction grating is formed along a rotary direction thereof, comprising the steps of: illuminating a predetermined position of the diffraction grating with a laser beam; directing diffracted light beams of ±m-order created at the predetermined position to another position of the diffraction grating different from the predetermined position; forming an interference light beam by superimposing a rediffracted light beam of ±m-order produced by diffracting the diffracted light beam of ±m-order and a rediffracted light beam of -m-order produced by diffracting the diffracted light beam of -m-order emitting from the another position; and detecting the rotating state of the rotating body on the basis of the interference light beam.
Claim 45
Dependent Claim
37 words
A method according to claim 34, wherein diffracted light beams are directed to the predetermined position and the another position which are symmetrical to each other with respect to the center of rotation of the rotating body.
Claim 46
Independent Claim
112 words
A method for detecting a rotating state of a rotating body on which a diffraction grating is formed along a rotary direction thereof, comprising the steps of: illuminating a predetermined position of the diffraction grating with a laser beam; directing first and second diffracted light beams created at the predetermined position to another position of the diffraction grating different from the predetermined position, wherein the predetermined position and the another position are optically conjugate to each other; forming an interference light beam by superimposing first and second re-diffracted light beams emitting from the another position; and detecting the rotating state of the rotating body on the basis of the interference light beam.
Claim 47
Independent Claim
112 words
A method for detecting a rotating state of a rotating body on which a diffraction grating is formed along a rotary direction thereof, comprising the steps of: illuminating a predetermined position of the diffraction grating with a laser beam; directing first and second diffracted light beams created at the predetermined position to another position of the diffraction grating different from the predetermined position, wherein the predetermined position and the another position are optically conjugate to each other; forming an interference light beam by superimposing first and second re-diffracted light beams emitting from the another position; and detecting the rotating state of the rotating body on the basis of the interference light beam.
Claim 48
Dependent Claim
40 words
A method according to claim 36, wherein the diffracted light beams are directed to the predetermined position and the another position, with the positions being symmetrical to each other with respect to the center of rotation of said rotating body.
Claim 49
Dependent Claim
61 words
A method according to claim 36, wherein the first and second diffraction light beams are a +1 order number and -1 order number, respectively, and the first rediffraction light beam is +1 order number produced by diffracting the first diffraction light beam, and the second rediffracton light beam is a -1 order number produced by diffracting the second diffraction light beam.
Claim 50
Dependent Claim
109 words
A rotation condition detecting apparatus comprising: optical means for directing a radiation beam to a diffraction grating formed on a rotating body along a rotary direction thereof, said optical means illuminating the diffracting grating with the radiation beam in a direction substantially perpendicular to a radial direction of the rotating body, with the radiation beam having a long and narrow shape in the rotary direction; light receiving means for photoelectrically converting an interference fringe formed by diffracted lights of predetermined orders emitting from the diffraction grating; and detecting means for detecting a rotating condition of the rotating body on the basis of a signal from said light receiving means.
Claim 51
Dependent Claim
109 words
A rotation condition detecting apparatus comprising: optical means for directing a radiation beam to a diffraction grating formed on a rotating body along a rotary direction thereof, said optical means illuminating the diffracting grating with the radiation beam in a direction substantially perpendicular to a radial direction of the rotating body, with the radiation beam having a long and narrow shape in the rotary direction; light receiving means for photoelectrically converting an interference fringe formed by diffracted lights of predetermined orders emitting from the diffraction grating; and detecting means for detecting a rotating condition of the rotating body on the basis of a signal from said light receiving means.
Claim 52
Dependent Claim
159 words
A rotating condition detection apparatus comprising: first optical means for directing a radiation beam to a first position of a diffraction grating formed on a rotating body along a rotary direction thereof; second optical means, including total reflection mirror members arranged so that an incident optical path and a reflection optical path are different from each other, for projecting diffracted lights of ±m-order emitting from said first position to a second position of the diffraction grating different from said first position and making a re-diffracted light of ±m-order obtained by diffracting said diffracted light of ±m-order and a re-diffracting light of -m-order obtained by diffracting said diffracted light of -m-order emitted from said second position in substantially the same direction; light receiving means for photoelectrically converting an interference light formed by said re-diffracted lights of ±m-order; and detecting means for detecting a rotating condition of the rotating body on the basis of a signal from said light receiving means.
Claim 53
Dependent Claim
159 words
A rotating condition detection apparatus comprising: first optical means for directing a radiation beam to a first position of a diffraction grating formed on a rotating body along a rotary direction thereof; second optical means, including total reflection mirror members arranged so that an incident optical path and a reflection optical path are different from each other, for projecting diffracted lights of ±m-order emitting from said first position to a second position of the diffraction grating different from said first position and making a re-diffracted light of ±m-order obtained by diffracting said diffracted light of ±m-order and a re-diffracting light of -m-order obtained by diffracting said diffracted light of -m-order emitted from said second position in substantially the same direction; light receiving means for photoelectrically converting an interference light formed by said re-diffracted lights of ±m-order; and detecting means for detecting a rotating condition of the rotating body on the basis of a signal from said light receiving means.
Claim 54
Dependent Claim
51 words
A rotating condition detecting apparatus according to claim 40, wherein said first and second optical means illuminates the diffraction grating with the radiation beam in a direction substantially perpendicular to a radial direction of the rotating body, with the radiation beam having a long and narrow shape in the rotary direction.
Claim 55
Dependent Claim
42 words
A rotating condition detecting apparatus according to claim 40, wherein the distance between said first position and the rotational center of the rotating body is approximately equal to the distance between said second position and the rotational center of the rotating body.
Claim 56
Dependent Claim
30 words
A rotating condition detecting apparatus according to claim 42, wherein the rotational center of the rotating body is on a line extending from said first position to said second position.
Claim 57
Independent Claim
134 words
A method for detecting a rotating state of a rotating body on which a diffraction grating is formed along a rotary direction thereof, comprising the steps of: illuminating a predetermined position of the diffraction grating with a radiation beam; directing first and second diffracted light beams created at said predetermined position to another position on the diffraction grating different from said predetermined position by total reflection mirror members arranged so that an incident optical path and a reflection optical path are different from each other, wherein said predetermined position and the another position are optically conjugate to each other; forming an interference light beam by superimposing first and second re-diffracted light beams emitting from the another position; and detecting the rotating state of the rotating body on the basis of the interference radiation beam.
Claim 58
Independent Claim
134 words
A method for detecting a rotating state of a rotating body on which a diffraction grating is formed along a rotary direction thereof, comprising the steps of: illuminating a predetermined position of the diffraction grating with a radiation beam; directing first and second diffracted light beams created at said predetermined position to another position on the diffraction grating different from said predetermined position by total reflection mirror members arranged so that an incident optical path and a reflection optical path are different from each other, wherein said predetermined position and the another position are optically conjugate to each other; forming an interference light beam by superimposing first and second re-diffracted light beams emitting from the another position; and detecting the rotating state of the rotating body on the basis of the interference radiation beam.
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