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EP0480442A1
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Sensing coil and fiber-optic gyroscope using the same
Assignee: Panasonic Holdings Corp
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Filing: 1991-10-10
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Granted: —
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Expires: 2011-10-10
Abstract
Abstract An optical fiber sensing coil (11) incorporated in a fiber-optic gyroscope has a square shape in cross section with corners rounded so as to avoid a sharp rise in transmission loss and breakage of the sensing coil which would otherwise occur when an optical fiber of the sensing coil is bent acutely. The square sensing coil is capable of providing a greater sensitivity than a conventional hollow cylindrical sensing coil provided that the length of the optical fiber is constant. In addition, the square sensing coil is received closely in a rectangular parallelepipedic box so that the inside space of the box can be used most efficiently.
Inventors
- 👤 Yoshinori Takeuchi
- 👤 Hidehiko Negishi
- 👤 Yuko Takei
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 08:15
CPC Classifications
G; G01; G01C; G01C19/00; G01C19/58; G01C19/64; G01C19/72; G01C19/721; G01C19/722
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
84 words
A sensing coil (11) formed of an optical fiber for use in a fiber-optic gyroscope capable of obtaining information about the position of an object from a phase difference between two counter-propagating beams in said optical fiber induced due to the Sagnac effect, said sensing coil being wound about a winding axis to contour a polygonal shape in a plane perpendicular to said winding axis, said polygonal shape consisting of straight lines and round corners each joining two adjacent ones of the straight lines.
Claim 2
Dependent Claim
17 words
A sensing coil according to claim 1, wherein said polygonal shape is a square having round corners.
Claim 3
Dependent Claim
61 words
A sensing coil according to claim 2, wherein said optical fiber forming said square sensing coil (11) has a length L related to the sensitivity S of said fiber-optic gyroscope such that L=S(4 l +2πr)/[(2r+ l )²+(π-4)r²] where l is the length of one side of said square, and r is the radius of curvature of round corners of said square.
Claim 4
Dependent Claim
17 words
A sensing coil according to claim 1, wherein said polygonal shape is a rectangle having round corners.
Claim 5
Dependent Claim
133 words
A fiber-optic gyroscope comprising a light source (13), a sensing coil (11) formed of an optical fiber for receiving light emitted from said light source (13) via a first predetermined optical path and for causing Sagnac effect active on the light in said optical fiber, photodetection means (16) for detecting light emerging from said sensing coil (11) via a second predetermined optical path, and phase modulation means (15) for modulating the phase of light propagating in said optical fiber of said sensing coil (11) to a predetermined phase, characterized in that said sensing coil (11) is wound about a winding axis to contour a polygonal shape in a plane perpendicular to said winding axis, said polygonal shape consisting of straight lines and round corners each joining two adjacent ones of the straight lines.
Claim 6
Dependent Claim
17 words
A fiber-optic gyroscope according to claim 5, wherein said polygonal shape is a square having round corners.
Claim 7
Dependent Claim
71 words
A fiber-optic gyroscope-according to claim 6, wherein said fiber-optic gyroscope has a sensitivity S for obtaining information about the position of an object, said optical fiber of said sensing coil (11) having a length L related to the sensitivity S such that L=S(4 l +2πr)/[(2r+ l )²+(π-4)r²] where l is the length of one side of said square, and r is the radius of curvature of round corners of said square.
Claim 8
Dependent Claim
17 words
A fiber-optic gyroscope according to claim 5, wherein said polygonal shape is a rectangle having round corners.
Claim 9
Dependent Claim
52 words
A fiber-optic gyroscope according to claim 5, further comprising polarizing means (14) disposed in said first optical path between said light source (13) and said sensing coil (11) and/or in said second optical path between sensing coil (11) and said photodetection means (16) for polarizing light passing therethrough in a predetermined direction.
Claim 10
Dependent Claim
20 words
A fiber-optic gyroscope according to claim 9, wherein said light source (13) comprises a semiconductor laser or a superluminescent diode.
Claim 11
Dependent Claim
39 words
A fiber-optic gyroscope according to claim 9 or 10, wherein said light source (13), said photodetection means (16), said phase modulation means (15) and said polarizing means (14) are disposed in a space defined by said sensing coil (11).
References Cited (Backward Citations)
EP0383231A2
Cited
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