US3932039A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulsed polarization device for measuring angle of rotation
Assignee: Westinghouse Electric Corp
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Filing: 1974-08-08
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Granted: 1976-01-13
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Expires: 1994-08-08
Abstract
Abstract An electro-optical system is disclosed for measuring rotational angle. The system includes a radiation source and reference linear polarizer in combination with a plurality of linear target polarizers. Photosensors are arranged to receive modulated light separately from an adjacent pair of target polarizers. Pulsed electrical output signals representative of the modulated light received by the photosensors are generated. Means are provided for comparing output signals from the sensors and generating a signal representative of rotational angle between the reference and target. The angle of rotation between the reference linear polarizer and the target linear polarizers is thereby converted to a representative signal which may be used to drive a servo motor or other device operatively connected to a rotatable element directly or indirectly. The reference polarizer may be held in a fixed position or it may be mounted on an independently rotatable element. Angle measurement systems herein disclosed may be used in servo loops, as follow-up control devices or angle measurement pick-off applications. Devices controlled by an operator head motion can be used for hand-free control of machines, tools, weapon systems, or radar antenna positioning systems. Because mechanical linkages are not required between most elements of the system, systems according to the present invention are especially useful for remote optically-coupled sensing and control systems.
Inventors
- 👤 Donald G. Frey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:50
CPC Classifications
G; G02; G02F; G02F1/00; G01; G01B; G01B11/00; G01B11/26; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/344; G01D5/345
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
172 words
An electro-optical system for measuring angular rotation which comprises: means for providing a pulsed source of non-polarized light; first linear polarizer means; a plurality of second linear polarizer means mounted adjacent one another in a common plane and being angularly disposed about an axis of rotation and substantially fixed with regard to their respective directions of linear polarization; means for directing light along a plurality of paths through said first polarizer means and said plurality of second polarizer means; photosensor means for detecting light along each of said plurality of paths from said first polarizer means and said plurality of second polarizer means and for providing output signals representative of light intensity received by said photosensor means; and processing means responsive to said output signals of said photosensor means for determining equality between the amplitude ratio of output signals corresponding to adjacent polarizer means and a reference value and generating a signal representative of rotation angle between said first polarizer means and said plurality of second polarizer means when said equality occurs.
Claim 2
Dependent Claim
172 words
An electro-optical system for measuring angular rotation which comprises: means for providing a pulsed source of non-polarized light; first linear polarizer means; a plurality of second linear polarizer means mounted adjacent one another in a common plane and being angularly disposed about an axis of rotation and substantially fixed with regard to their respective directions of linear polarization; means for directing light along a plurality of paths through said first polarizer means and said plurality of second polarizer means; photosensor means for detecting light along each of said plurality of paths from said first polarizer means and said plurality of second polarizer means and for providing output signals representative of light intensity received by said photosensor means; and processing means responsive to said output signals of said photosensor means for determining equality between the amplitude ratio of output signals corresponding to adjacent polarizer means and a reference value and generating a signal representative of rotation angle between said first polarizer means and said plurality of second polarizer means when said equality occurs.
Claim 3
Dependent Claim
24 words
The system of claim 1 wherein adjacent second polarizer means are disposed at a fixed mechanical angle greater than 0° and less than 90°.
Claim 4
Dependent Claim
23 words
The system of claim 1 wherein adjacent second polarizer means are disposed with their respective mechanical axes of polarization direction at substantially 45°.
Claim 5
Dependent Claim
14 words
The system of claim 1 wherein the pulsed source comprises pulsed light-emitting diode means.
Claim 6
Dependent Claim
19 words
The system of claim 4 wherein there is included energizing means for applying pulse signals to said diode means.
Claim 7
Dependent Claim
23 words
The system of claim 1 wherein said first and second polarizer means comprise sheet polarizers mounted transversely between the plurality of the paths.
Claim 8
Dependent Claim
28 words
The system of claim 1 wherein the plurality of second polarizer means comprises a pair of matched polarizer sheets mounted in fixed coplanar relationship on a rotatable body.
Claim 9
Dependent Claim
22 words
The system of claim 7, wherein the pulsed source and first polarizer means are integrally mounted as a fixed index transmitter assembly.
Claim 10
Dependent Claim
30 words
The system of claim 7, wherein said pair of polarizer sheets is mounted in overlying relationship with a corresponding pair of substantially flat electro-optical sensors to form a receiver assembly.
Claim 11
Dependent Claim
23 words
The system of claim 1, wherein said pulsed source polarizer means, and photosensor means comprise matched narrowband spectral width emitter and receiver portions.
Claim 12
Dependent Claim
82 words
The system as claimed in claim 1, wherein said pulsed source means and said plurality of second linear polarizer means comprise a first assembly mounted at a reference position, said pulsed source means comprising first and second devices for emitting light along the paths through corresponding ones of said second linear polarizing means; and a second assembly comprising said first linear polarizer means and said photosensor means mounted rotatively with respect to the first assembly and fixed with respect to each other.
Claim 13
Dependent Claim
36 words
The system as claimed in claim 11, wherein said processing means further comprises gating means for separating the signals generated in response to the light emitted from the first and second devices onto said photosensor means.
Claim 14
Dependent Claim
118 words
The system as claimed in claim 1, wherein said processing means comprises analog-to-digital converter means for converting the analog outputs of said photosensor means into digital form, divider means for providing a digital output signal indicative of the amplitude ratio of the output signals of said photosensor means, read-only memory (ROM) means programmed to provide corresponding first and second outputs in digital form indicative of cyclical signals displaced from each other by a given angle θ, means for providing in digital form a manifestation of the ratio of the first and second outputs, and digital comparator means for providing an indication of equality between the reference signals as derived from said ratio providing means and said divider means.
Claim 15
Dependent Claim
57 words
The system as claimed in claim 13, wherein there is further included counter means for generating and applying an address signal to each of said first and second ROM means, and means coupled to said counter and responsive to the output of said digital comparator means to provide a digital output signal indicative of the angular rotation.
Claim 16
Dependent Claim
213 words
Apparatus for measuring rotational angle of a movable target element with relation to a reference position, said apparatus comprising: means for directing non-polarized electromagnetic waves along paths toward first and second electromagnetic wave detectors; reference position polarizer means mounted transverse to the paths for polarizing the waves in a reference orientation; first and second polarization analyzers rotatably mounted on the movable target element in a common plane transverse to the paths between said reference position polarizer means and said first and second detectors, said first and second analyzers being disposed adjacently to provide a fixed angle greater than 0° and less than 90° between polarization directional axes of said first and second adjacent analyzers, said first and second detectors being responsive to the electromagnetic waves for generating first and second output signals representing the intensity of the waves received by each of said first and second detectors along paths corresponding to said first and second analyzers; and means responsive to said first and second output signals from said detectors for determining equality between the amplitude ratio of first and second output signals corresponding to said first and second analyzers and a reference value and generating a signal representative of rotational angle between the movable element and the reference position when said equality occurs.
Claim 17
Dependent Claim
213 words
Apparatus for measuring rotational angle of a movable target element with relation to a reference position, said apparatus comprising: means for directing non-polarized electromagnetic waves along paths toward first and second electromagnetic wave detectors; reference position polarizer means mounted transverse to the paths for polarizing the waves in a reference orientation; first and second polarization analyzers rotatably mounted on the movable target element in a common plane transverse to the paths between said reference position polarizer means and said first and second detectors, said first and second analyzers being disposed adjacently to provide a fixed angle greater than 0° and less than 90° between polarization directional axes of said first and second adjacent analyzers, said first and second detectors being responsive to the electromagnetic waves for generating first and second output signals representing the intensity of the waves received by each of said first and second detectors along paths corresponding to said first and second analyzers; and means responsive to said first and second output signals from said detectors for determining equality between the amplitude ratio of first and second output signals corresponding to said first and second analyzers and a reference value and generating a signal representative of rotational angle between the movable element and the reference position when said equality occurs.
Claim 18
Dependent Claim
32 words
Apparatus according to claim 15, wherein said reference position polarizer means is mounted as a fixed index and includes a polarizer sheet overlying a pulsed light source, thereby forming a transmitter assembly.
Claim 19
Dependent Claim
98 words
Apparatus according to claim 15, wherein said processing means comprises reference means for generating first and second cyclical reference signals separated from each other by a given angle and having a common reference point, comparator means for determining when the ratio of the output signals derived from said first and second detectors equals the ratio of the reference signals, and means for determining the time period between the reference point and the point at which the ratio equality occurs to provide an indication of the rotational angle of the movable target element with respect to the reference position.
Claim 20
Dependent Claim
76 words
Apparatus according to claim 17, wherein said comparator means includes first multiplier means for multiplying the first output signal by the second reference signal to provide a first product signal indicative thereof, second multiplier means for multiplying the second output signal by the first reference signal to provide a second product signal indicative thereof, and means responsive to the first and second product signals to provide an equality signal of the occurrence of an equality therebetween.
Claim 21
Dependent Claim
101 words
Apparatus according to claim 18, wherein said reference means provides a signal indicative of the occurrence of the common reference point, and said determining means comprises generator means for initiating the generation of a ramp signal in response to the occurrence of the reference point signal, and means for limiting the amplitude of the ramp signal as derived from said generator means in response to the occurrence of the equality signal, and means responsive to the limited signal for deriving an indication of its amplitude to provide an indication of the angle rotation between the target element and the reference position.
Claim 22
Dependent Claim
153 words
In a device for measuring rotational angle wherein plane polarized light is directed to be received by rotatable polarization analyzer means operatively connected to a remote rotary body for which rotational angle relative to a reference position is measured, the improvement which comprises: a plurality of polarization analyzers mounted side-by-side transverse to plane polarized light received by said analyzer means, each of said analyzers having a directional axis of linear polarization; means for holding said analyzers to maintain a substantially fixed axial angle between said analyzers about an axis of rotation; photosensor means for receiving light independently through each of said analyzers and generating time pulsed electrical signals with amplitude representative of modulated light intensity for each analyzer; and means for determining equality between the amplitude ratio of said time pulses electrical signals and a reference value adjacent photosensor signals and generating an output signal representative of rotational angle when said equality occurs.
Claim 23
Dependent Claim
153 words
In a device for measuring rotational angle wherein plane polarized light is directed to be received by rotatable polarization analyzer means operatively connected to a remote rotary body for which rotational angle relative to a reference position is measured, the improvement which comprises: a plurality of polarization analyzers mounted side-by-side transverse to plane polarized light received by said analyzer means, each of said analyzers having a directional axis of linear polarization; means for holding said analyzers to maintain a substantially fixed axial angle between said analyzers about an axis of rotation; photosensor means for receiving light independently through each of said analyzers and generating time pulsed electrical signals with amplitude representative of modulated light intensity for each analyzer; and means for determining equality between the amplitude ratio of said time pulses electrical signals and a reference value adjacent photosensor signals and generating an output signal representative of rotational angle when said equality occurs.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-01-12 | 1979-07-14 | 1980-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-12 | 1983-07-14 | 1984-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-12 | 1987-07-14 | 1988-01-13 | $7700.00 | Window Closed / Lapsed |