EP0051394A1
Expired / Lapsed
EP
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Electrooptical modulator
Assignee: Xerox Corp
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Filing: 1981-10-21
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Granted: —
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Expires: 2001-10-21
Abstract
Abstract An electrooptical modulator arranged to act as a scanning device for deflection of an optical beam of light across an image plane. The device comprises a body (12) of electrooptical crystal material and a periodic array of parallel, spaced electrodes (20) associated with one surface of the body. A light beam (16) entering the crystal body is caused to interact with electric fields established at the one surface by step applied voltages to the electrode array that influence the deflection of the light beam at the moment of total internal reflection at the one surface. By varying the magnitude of the applied voltages across the electrodes, a corresponding approximation of a desired phase retardation can be produced along the phase front of the light beam. The phase retardation across the light beam can be designed to produce a linear phase front (39) angled beam or can be designed to produce a curvilinear phase front forming a focused spot at the image plane.
Inventors
- 👤 Donald R. Scifres
- 👤 Robert A. Sprague
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 08:27
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/29; G02F1/292; G02F1/01; G02F1/03
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
181 words
An electrooptical modulator comprising a body (12) of electrooptical material, a source of light for providing a wide beam (16) of light through said body, and a periodic array of spaced electrodes (20) associated with one surface (23) of said body, at least a portion of the lengths of said electrodes extending in the general direction of travel of said light beam and arranged, in response to a voltage applied thereto, to provide an electric field in said body along said electrode portions to influence the deflection of said light beam at the moment of total internal reflection at said one surface, characterised by means (22) to apply voltages to said electrodes (20) which vary to a predetermined value over several of said electrodes to produce a corresponding approximation of a phase retardation along the phase front of said light beam, and - means (32) to change the magnitude of said applied voltages across said electrodes to vary the approximation of the phase retardation along said phase front to cause said light beam to scan about or across an image plane.
Claim 2
Dependent Claim
181 words
An electrooptical modulator comprising a body (12) of electrooptical material, a source of light for providing a wide beam (16) of light through said body, and a periodic array of spaced electrodes (20) associated with one surface (23) of said body, at least a portion of the lengths of said electrodes extending in the general direction of travel of said light beam and arranged, in response to a voltage applied thereto, to provide an electric field in said body along said electrode portions to influence the deflection of said light beam at the moment of total internal reflection at said one surface, characterised by means (22) to apply voltages to said electrodes (20) which vary to a predetermined value over several of said electrodes to produce a corresponding approximation of a phase retardation along the phase front of said light beam, and - means (32) to change the magnitude of said applied voltages across said electrodes to vary the approximation of the phase retardation along said phase front to cause said light beam to scan about or across an image plane.
Claim 3
Dependent Claim
46 words
The modulator of claim 1 wherein said applied voltages are applied in a stepwise manner to produce a stepwise approximation of a linear phase front across said light beam at an angle relative to a line perpendicular to the direction of travel of said light beam.
Claim 4
Dependent Claim
43 words
The modulator of claim 1 wherein said applied voltages are applied in a stepwise manner to produce a stepwise approximation of a curvilinear phase front across said light beam to cause the deflected light to focus to a spot at said image plane.
Claim 5
Dependent Claim
26 words
The modulator of claim 1 wherein said applied voltages are applied in discrete groups of electrodes across said array to produce a plurality of light beams.
Claim 6
Dependent Claim
32 words
The modulator of claim 4 wherein the magnitude of said applied voltages are varied within said discrete groups to cause said light beams to independently scan about or across said image plane.
Claim 7
Dependent Claim
53 words
The modulator of claim 1 wherein said. applied voltages are applied in discrete groups across said array to produce a plurality of focused spots at said image plane, the magnitude of said applied voltages being varied within said discrete groups to cause said spots to independently scan about or across said image plane.
Claim 8
Dependent Claim
19 words
The modulator of any one of claims 1 to 6 wherein the spatial periodicity of said electrodes is equal.
Claim 9
Dependent Claim
19 words
The modulator of any one of claims 1 to 6 wherein the spatial periodicity of said electrodes is unequal.
Claim 10
Dependent Claim
81 words
The modulator of any one of claims 1 to 8 wherein said applied voltages are applied so as to vary to a predetermined maximum value over several of said electrodes as a periodic function -across the electrode array, and applied so that each electrode is voltage referenced to an adjacent electrode, and wherein said means to change the magnitude of said applied voltages across said electrodes changes the periodicity of their application and distribution to said maximum value across said array.
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