EP0391278A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Doppler velocity meter
Assignee: Canon Inc
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Filing: 1990-03-30
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Granted: —
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Expires: 2010-03-30
Abstract
Abstract A Doppler velocity meter has a radiation source for emitting a radiation beam the wavelength of which fluctuates, such as a laser; an optical system for directing the radiation beam to an object (7) at an incident angle ϑ and a detector (9) for detecting scattered beam generated from the object by directing the radiation beam. The optical system has a diffraction grating (10) which serves to change the incident angle ϑ in accordance with a change in the wavelength λ of the radiation beam in such a manner as to maintain the value of sin ϑ/λ substantially constant. The velocity meter can accurately detect the velocity of movement of the object regardless of any change in the wavelength λ, because the diffraction grating serves to substantially compensate for any change in the frequency of the scattered beam caused by the change in the wavelength.
Inventors
- 👤 Kadowaki Hidejiro
- 👤 Ken Tsuchii
- 👤 Makoto Takamiya
- 👤 Kosuke Yamamoto
- 👤 Masafumi Wataya
- 👤 Toshiyuki Yanaka
- 👤 Haruhiko Takahashi
- 👤 Hiroshi Sugiyama
- 👤 Yasuhiko Ishida
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 12:44
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/48; G01S7/481; G01S7/4811; B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/07; B41J2/125; G01S17/00; G01S17/02; G01S17/50; G01S17/58; B41J11/00; B41J11/36; B41J11/42
Claims Analysis
Total Claims: 54
Claim 1
Independent Claim
96 words
A laser Doppler velocity meter comprising: a laser for emitting a laser beam; an optical system for applying said laser beam to an object at an incident angle ϑ, said optical system varying the incident angle ϑ in accordance with a change in the wavelength λ of said laser beam so as to maintain the value of sin ϑ/λ substantially constant; and a detector for detecting the scattered light generated on said object in response to the application of said laser beam and for producing a signal corresponding to the frequency of the received scattered light.
Claim 2
Dependent Claim
96 words
A laser Doppler velocity meter comprising: a laser for emitting a laser beam; an optical system for applying said laser beam to an object at an incident angle ϑ, said optical system varying the incident angle ϑ in accordance with a change in the wavelength λ of said laser beam so as to maintain the value of sin ϑ/λ substantially constant; and a detector for detecting the scattered light generated on said object in response to the application of said laser beam and for producing a signal corresponding to the frequency of the received scattered light.
Claim 3
Dependent Claim
16 words
A laser Doppler velocity meter according to Claim 2, wherein said laser includes a semiconductor laser.
Claim 4
Dependent Claim
25 words
laser Doppler velocity meter according to Claim 1, wherein said optical system substantially collimates said laser beam and applyies the collimated beam to said object.
Claim 5
Dependent Claim
68 words
A laser Doppler velocity meter according to Claim 3, wherein said optical system includes: a collimator lens for collimating said laser beam emitted from said laser; a beam splitter for splitting the collimated beam into a first beam and a second beam; and means for directing said first and second beams to said object such that said first and second beams cross at a point on said object.
Claim 6
Dependent Claim
49 words
A laser Doppler velocity meter according to Claim 4, wherein said beam splitter has a diffraction grating for diffracting said collimated beam so as to form a diffracted light of an order +n as said first beam and a diffracted light of an order -n as said second beam.
Claim 7
Dependent Claim
60 words
A laser Doppler velocity meter according to Claim 5, wherein said optical system directs said first and second beams such that the angle at which said first and second beams cross each other at said point on said object is equal to an angle formed between said first and gecond beams when these beams are emitted from said diffraction grating.
Claim 8
Dependent Claim
39 words
A laser Doppler velocity meter according to Claim 6, further comprising: means for moving said diffraction grating in a direction of arrangement of the grating at a constant speed such that the frequency of said scattered light is increased.
Claim 9
Dependent Claim
44 words
A laser Doppler velocity meter according to Claim 7, further comprising a band-pass filter for filtering the output from said detector, so that the velocity of movement of said obf ect is determined on the basis of the signal obtained through said band-pass filter.
Claim 10
Dependent Claim
17 words
A laser Doppler velocity meter according to Claim 7, wherein said band-pass filter includes a high-pass filter.
Claim 11
Dependent Claim
61 words
A laser Doppler velocity meter according to Claim 6, further comprising: means for moving said diffraction grating in a direction of arrangement of the grating at a constant speed so as to modulate the frequency of said scattered light; whereby the velocity and direction of movement of said object are detected on the basis of the output signal from said detector.
Claim 12
Dependent Claim
49 words
A laser Doppler velocity meter according to Claim 6, wherein said optical system is so arranged to provide a substantially optically-conjugate relation between the positions where said first and second beams are emitted from said diffraction grating and the position where said first and second beams cross each other.
Claim 13
Dependent Claim
23 words
A laser Doppler velocity meter according to Claim 11, wherein said optical system includes a lens assembly for providing said substantially optically-conjugate relation.
Claim 14
Dependent Claim
77 words
A laser Doppler velocity meter according to Claim 6, wherein said optical system includes: second diffraction gratings having a grating pitch substantially equal to that of said diffraction grating and capable of diffracting said first and second beams respectively, thereby directing said first and second beams along parallel light paths; and a deflector for deflecting said first and second beams from said second diffraction gratings so as to direct said first and second beams to said object.
Claim 15
Dependent Claim
43 words
A laser Doppler velocity meter according to Claim 13, wherein said deflector includes a third diffraction grating for diffracting and deflecting said first and second beams, said third diffraction grating having a grating pitch substantially equal to that of said second diffraction gratings.
Claim 16
Dependent Claim
41 words
A laser Doppler velocity meter according to Claim 13, wherein said deflector includes a lens system for ref racting and deflecting said first and second beams, said lens system being mounted such that its focal point is positioned on said object.
Claim 17
Dependent Claim
20 words
A laser Doppler velocity meter according to Claim 6, wherein said diffraction grating is capable of reflection-diffracting said collimated beam.
Claim 18
Dependent Claim
18 words
A laser Doppler velocity meter according to Claim 16, wherein said detector detects light reflection-scattered by said object.
Claim 19
Dependent Claim
29 words
A laser Doppler velocity meter according to Claim 17, wherein said laser is disposed at a position outside the plane containing the paths of said first and second beams.
Claim 20
Dependent Claim
29 words
A laser Doppler velocity meter according to Claim 17, wherein said detector is disposed at a position outside a plane containing the paths of said first and second beams.
Claim 21
Dependent Claim
41 words
A laser Doppler velocity meter according to Claim 6, wherein said detector has a photoelectric converter and an image-forming lens which provides a substantially optically conjugate relation between a light-receiving surface of said photoelectric converter and the surface of said object.
Claim 22
Dependent Claim
34 words
A laser Doppler velocity meter according to Claim 1, wherein said optical system has a diffraction grating for diffracting and deflecting said laser beam so as to direct said laser beam to said object.
Claim 23
Dependent Claim
43 words
A laser Doppler velocity meter according to Claim 21, wherein said optical system directs said laser beam to said diffraction grating at an incident angle which is substantially equal to an angle of diffraction of said laser beam effected by said diffraction grating.
Claim 24
Dependent Claim
57 words
A laser Doppler velocity meter according to Claim 21, wherein said optical system is arranged to diffract said laser beam by said diffraction grating thereby generating first and second diffracted beams and to direct said first and second diffracted beams to said object such that said diffracted beams cross each other at a point on said object.
Claim 25
Dependent Claim
26 words
A laser Doppler velocity meter according to Claim 21, wherein said optical system is arranged to cause reflection-diffraction of said laser beam by said diffraction grating.
Claim 26
Dependent Claim
60 words
A laser Doppler velocity meter according to Claim 23, wherein said optical system is arranged such that the angle at which said first and second diffracted beams cross each other at said point on said object is substantially equal to an angle formed between said first and second diffracted beams when these diffracted beams are emitted from said diffraction grating.
Claim 27
Dependent Claim
33 words
A laser Doppler velocity meter according to Claim 23, wherein said first diffracted beam is of a positive number of order, while said second diffracted beam is of a negative number of order.
Claim 28
Dependent Claim
33 words
A laser Doppler velocity meter according to Claim 21, further comprising means for moving said diffraction grating at a constant velocity in a direction of arrangement of the gratings of said diffraction grating.
Claim 29
Dependent Claim
26 words
A laser Doppler velocity meter according to Claim 21, wherein said optical system provides a substantially optically -conjugate relation between said diffraction grating and said object.
Claim 30
Dependent Claim
16 words
A laser Doppler velocity meter according to Claim 1, wherein said laser includes a semiconductor laser.
Claim 31
Dependent Claim
18 words
A laser Doppler velocity meter according to Claim 24, wherein said detector detects light reflection-scattered by said object.
Claim 32
Dependent Claim
148 words
A laser Doppler velocity meter comprising: a laser for emitting a laser beam: an optical system including a diffraction grating for diffracting and deflecting said laser beam so as to generate first and second diffracted beams, said optical system being capable of directing said first and second diffracted beams to an object such that said first and second diffracted beams cross each other on said object forming therebetween an angle which is substantially equal to an angle formed between said first and second diffracted beams when these diffracted beams are emitted from said diffraction grating; and a detector capable of detecting an interference beam which is formed as a result of an interference between a first scattered light formed on said object by said first diffracted beam and a second scattered light formed on said object by said second diffracted beam,and converting said interference beam into a signal.
Claim 33
Dependent Claim
148 words
A laser Doppler velocity meter comprising: a laser for emitting a laser beam: an optical system including a diffraction grating for diffracting and deflecting said laser beam so as to generate first and second diffracted beams, said optical system being capable of directing said first and second diffracted beams to an object such that said first and second diffracted beams cross each other on said object forming therebetween an angle which is substantially equal to an angle formed between said first and second diffracted beams when these diffracted beams are emitted from said diffraction grating; and a detector capable of detecting an interference beam which is formed as a result of an interference between a first scattered light formed on said object by said first diffracted beam and a second scattered light formed on said object by said second diffracted beam,and converting said interference beam into a signal.
Claim 34
Dependent Claim
33 words
A laser Doppler velocity meter according to Claim 31, wherein said first diffracted beam is of a positive number of order, while said second diffracted beam is of a negative number of order.
Claim 35
Dependent Claim
35 words
A laser Doppler velocity meter according to Claim 32, wherein said first diffracted beam includes a diffracted beam of the order +1, while said second diffracted beam includes a diffracted beam of the order -1.
Claim 36
Dependent Claim
69 words
A laser Doppler velocity meter according to Claim 32, wherein said first diffracted beam and said second diffracted beam respectively form a first beam spot and a second beam spot on said object; and wherein said optical system is arranged such that the positions of said first and second beam spots on said object are maintained substantially constant regardless of any change in the wavelength of said laser beam.
Claim 37
Dependent Claim
23 words
A lager Doppler velocity meter according to Claim 32, wherein said first and second beam spots are formed respectively by substantially collimated means.
Claim 38
Dependent Claim
32 words
A laser Doppler velocity meter according to Claim 32, further comprising means for moving said diffraction grating at a constant velocity in a direction of arrangement of gratings of said diffraction grating.
Claim 39
Dependent Claim
39 words
A laser Doppler velocity meter according to Claim 32, wherein said diffraction grating forms said first and second diffracted beams by reflection-diffracting said laser beam; and wherein said detector is disposed to detect said first and second scattered lights.
Claim 40
Dependent Claim
16 words
A laser Doppler velocity meter according to Claim 32, wherein said lager includes a semiconductor laser.
Claim 41
Dependent Claim
33 words
A laser Doppler velocity meter according to Claim 32, wherein said diffraction grating includes a first grating for generating said first diffracted beam and a second grating for generating said second diffracted beam.
Claim 42
Dependent Claim
90 words
A velocity meter comprising: beam applying means for applying an emitted beam to an object; and detecting means for detecting a scattered beam generated on said object by application of said beam and producing a signal corresponding to the frequency of the detected scattered light; wherein said beam applying means changing an angle of incidence of said beam to said object in accordance with a change in the wavelength of said beam, so as to substantially compensate for a change in said frequency caused by said change in said wavelength.
Claim 43
Dependent Claim
90 words
A velocity meter comprising: beam applying means for applying an emitted beam to an object; and detecting means for detecting a scattered beam generated on said object by application of said beam and producing a signal corresponding to the frequency of the detected scattered light; wherein said beam applying means changing an angle of incidence of said beam to said object in accordance with a change in the wavelength of said beam, so as to substantially compensate for a change in said frequency caused by said change in said wavelength.
Claim 44
Dependent Claim
22 words
A velocity meter according to Claim 40, wherein said beam applying means includes means for applying a laser beam as said beam.
Claim 45
Dependent Claim
120 words
A velocity meter according to Claim 40, wherein said beam applying means includes: beam supplying means for supplying said beam; a beam splitting means for dividing said beam from said beam supplying means so as to generate first and second beams; and beam directing means for directing said first and second beams to said object, so that a first scattered beam and a second scattered beam are generated on said object in response to application of said first and second beams to said object; and wherein said detecting means includes: converting means for receiving an interference beam produced as a result of mutual interference between said first and second scattered beams and for converting said interference beam into said signal.
Claim 46
Dependent Claim
99 words
A velocity meter comprising: an emission source for emitting a beam the wavelength of which fluctuates substantially; directing means for directing said emitted beam from said emission source to an object; and detecting means for detecting scattered light generated on said object in response to application of said emitted beam and for producing a signal corresponding to the frequency of said scattered light; wherein said directing means for applying said emitted beam to said object in such a manner as to substantially suppress a change in said frequency caused by a fluctuation of the wavelength of said emitted beam.
Claim 47
Dependent Claim
99 words
A velocity meter comprising: an emission source for emitting a beam the wavelength of which fluctuates substantially; directing means for directing said emitted beam from said emission source to an object; and detecting means for detecting scattered light generated on said object in response to application of said emitted beam and for producing a signal corresponding to the frequency of said scattered light; wherein said directing means for applying said emitted beam to said object in such a manner as to substantially suppress a change in said frequency caused by a fluctuation of the wavelength of said emitted beam.
Claim 48
Dependent Claim
164 words
An image recording apparatus comprising: feeding means for feeding a recording medium; recording means for recording an image on said recording medium which is being fed by said feeding means; and a velocity meter for applying an emitted beam to a portion of a selected one of said recording medium and said feeding means and detecting a scattered beam scattered from said portion of said selected one of said recording medium and said feeding means, said velocity meter producing an output signal which corresponds to the frequency of the detected scattered beam and which indicates the velocity of feed of said recording medium, said velocity meter further changing an angle of incidence of said emitted beam to said portion of said selected one of said recording medium and said feeding means in accordance with a change in the wavelength of said emitted beam so as to compensate for a change in said frequency caused by said change in said wavelength of said emitted beam.
Claim 49
Dependent Claim
164 words
An image recording apparatus comprising: feeding means for feeding a recording medium; recording means for recording an image on said recording medium which is being fed by said feeding means; and a velocity meter for applying an emitted beam to a portion of a selected one of said recording medium and said feeding means and detecting a scattered beam scattered from said portion of said selected one of said recording medium and said feeding means, said velocity meter producing an output signal which corresponds to the frequency of the detected scattered beam and which indicates the velocity of feed of said recording medium, said velocity meter further changing an angle of incidence of said emitted beam to said portion of said selected one of said recording medium and said feeding means in accordance with a change in the wavelength of said emitted beam so as to compensate for a change in said frequency caused by said change in said wavelength of said emitted beam.
Claim 50
Dependent Claim
14 words
An image recording apparatus according to Claim 44, wherein said recording medium is paper.
Claim 51
Dependent Claim
24 words
An image recording apparatus according to Claim 44, wherein said velocity meter has a semiconductor laser for emitting a laser as said emitted beam.
Claim 52
Dependent Claim
62 words
An image recording apparatus according to claim 44, wherein said feeding means includes: a movable carrier for carrying said recording medium; driving means for driving said carrier in a predetermined direction; and control means for controlling said driving means in accordance with an output from said velocity meter so as to enable said carrier to be driven at a substantially constant velocity.
Claim 53
Dependent Claim
40 words
An image recording apparatus according to Claim 44, wherein said recording means includes: a recording head; and control means for controlling timing of recording of an image by said recording head in accordance with an output from said velocity meter.
Claim 54
Dependent Claim
25 words
An image recording apparatus according to Claim 48, wherein said recording head includes mans for directing ink to said recording medium thereby recording said image.
References Cited (Backward Citations)
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