EP0021852A1
Expired / Lapsed
EP
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Holographic scanning system
Assignee: Xerox Corp
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Filing: 1980-07-02
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Granted: —
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Expires: 2000-07-02
Abstract
Abstract A holographic scanning system includes a reflective type holographic spinner (20) having a plurality of diffraction gratings (24) on its surface. A reconstruction wavefront (25) incident on a non-grating surface (26) of the spinner is reflected (25') into a corrective optical element (28) which displaces and redirects the wavefront (27) so that it is incident at the grating (24) at an angle corrected for the effects of spinner wobble.
Inventors
- 👤 Charles J. Kramer
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 12:00
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/08; G02B26/10; G02B26/106
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
170 words
A holographic scanning system including a reflection holographic spinner (20) having on its surface at least one holographic facet (24) characterised by: a source of coherent light which directs a reconstruction light wavefront (25), onto a portion (26) of said spinner surface adjacent said facet at a first angle of incidence, θ i , said reconstruction wavefront being reflected from said surface; an optical element (28) disposed in the path of said reflected wavefront (25'), said element acting to condition said wavefront and redirect it (27) onto said holographic facet (24) at a second angle of incidence, said facet diffracting said wavefront (29) at a first order diffraction angle θ d ; means (22) for rotating said spinner so that said facet (24) is rotated across said reconstruction wavefront (27) producing a corresponding translation of the diffracted wavefront (29); and means (32) for focusing said diffracted wavefront, whereby a scan line is generated at an image plane (34) which is substantially invariant to the presence of spinner wobble during rotation.
Claim 2
Dependent Claim
170 words
A holographic scanning system including a reflection holographic spinner (20) having on its surface at least one holographic facet (24) characterised by: a source of coherent light which directs a reconstruction light wavefront (25), onto a portion (26) of said spinner surface adjacent said facet at a first angle of incidence, θ i , said reconstruction wavefront being reflected from said surface; an optical element (28) disposed in the path of said reflected wavefront (25'), said element acting to condition said wavefront and redirect it (27) onto said holographic facet (24) at a second angle of incidence, said facet diffracting said wavefront (29) at a first order diffraction angle θ d ; means (22) for rotating said spinner so that said facet (24) is rotated across said reconstruction wavefront (27) producing a corresponding translation of the diffracted wavefront (29); and means (32) for focusing said diffracted wavefront, whereby a scan line is generated at an image plane (34) which is substantially invariant to the presence of spinner wobble during rotation.
Claim 3
Dependent Claim
16 words
A holographic scanning system.as defined in Claim 1 wherein said optical element (28) is a retroreflector.
Claim 4
Dependent Claim
19 words
A holographic scanning system as defined in Claim 1 wherein said optical element (28) is a corner cube reflector.
Claim 5
Dependent Claim
30 words
A holographic scanning system as defined in Claim 1 wherein said optical element (28) is a feedback device which introduces a multiplier factor x into the redirected wavefront such that
Claim 6
Dependent Claim
79 words
A holographic scanning system as defined in claim 4 wherein said optical element is a retroreflector including a prism (28') located so that said reflected wavefront strikes a first surface of said prism at an angle θ 1 , is refracted at said first surface at an angle θ' 1 , strikes the second surface at an angle θ' 2 , and is refracted at said second surface at an angle θ 2 , the multiplier factor x being
Claim 7
Dependent Claim
57 words
A holographic scanning system as defined in any one of Claims 1 to 5 wherein said optical elementincludes a grating (60), said reflected wavefront being incident on said grating at an angle θ' i and diffracted by said grating at an angle θ' d , the feedback multiplier X of the element being given by the equation
Claim 8
Dependent Claim
63 words
A holographic scanning system as defined in claim 1 wherein said first angle of incidence is equal to said diffraction angle and further including a beamsplitter positioned in the path of the redirected wavefront and adapted to pass a portion of the redirected wavefront through to the facet surface while subsequently reflecting a portion of said diffraction waveform to generate the scan line.
Claim 9
Dependent Claim
36 words
A holographic scanning system as defined in any one of Claims 1 to 7 wherein said facets are zone-type lenses which diffract said redirected incident wavefront to reconstruct a spot light for scanning an image plane.
Claim 10
Dependent Claim
33 words
A holographic scanning system as defined in any one of Claims 1 to 7 wherein said facets are plane diffraction gratings which diffract an incident reconstruction wavefront into zeroth and first order components.
Claim 11
Dependent Claim
25 words
A holographic scanning system as defined in claim 9 including means for focusing said first order component as a scanning spot on an image plane.
References Cited (Backward Citations)
US3897132A
Cited
FR2394105A1
Cited
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