Abstract:
A system for remote measurement of structural forces includes a plurality of microbend transducers (14) mounted along the length of the structure (12) for microbending an optical fiber (16) in response to structural forces, such as stress acting upon an oil or gas pipeline or the like. An optical time domain reflectometer (OTDR) (18) has a light source (46) for launching a pulsed optical signal passage through the fiber and a photodetector (56) for sensing as a function of time the intensity of backscattered light reflected back through the fiber, wherein this sensed time function is correlated directly with discrete longitudinal positions along the length of the fiber and the structure. When one or more of the microbend transducers is activated to induce a microbend in the fiber response to localized forces acting upon the structure, a portion of the backscattered light is lost at the microbend. This attenuation in backscattered light intensity is sensed quantitatively and positionally identified by the photodetector. Specific preferred constructions for microbend transducers and system arrangements particularly adapted for detecting structurally strain in an oil or gas pipeline are disclosed.
Abstract:
An intensity-based, micro-bending optical fiber sensor is disclosed herein, which is configured to acquire clean, stable, and reliable vital sign signals. Related systems and methods for vital sign monitoring are also provided herein. The sensor of various embodiments includes a multi-mode optical fiber, an LED light source, an LED driver, a receiver, and a single layer deformer structure. In various embodiments, the optical fiber and single layer deformer structure of the sensor are selected to meet specific parameters necessary to achieve a level of reliability and sensitivity needed to successfully monitor vital signs. In some embodiments, a specific sizing relationship exists between the optical fiber and the single layer deformer structure. In some embodiments, the sensor is configured to acquire ballistocardiograph waveforms.
Abstract:
Die Erfindung betrifft ein Sensorband, das mindestens einen Lichtwellenleiter (11) und eine Umkehrstelle aufweist. Die Umkehrstelle ist mit dem Lichtwellenleiter (11) an einem ersten freien Ende des Lichtwellenleiters (11) optisch gekoppelt. Die Umkehrstelle ist ein Prisma (9).
Abstract:
Die Erfindung betrifft einen Prinzipiellen Aufbau für faseroptische Belastungssensoren, der in vielfältiger Weise ausgestaltet und abgewandelt werden kann. Er umfasst eine Stütz- und Störstruktur (1) mit in einer Ebene angeordneten stabförmigen Elementen, welche in periodischen Abständen von mindestens einer Lichtleitfaser (2) gekreuzt werden, wobei die Faser abwechselnd über und unter den Elementen verläuft. Die Stütz- und Störstruktur ist dabei so ausgeführt, dass bei der Herstellung kein Ende der Lichtleitfaser zwischen den stabförmigen Elementen hindurchgeführt zu werden braucht. Optional können Stütz- und Störstruktur und Lichtleitfaser von einer elastischen Umhüllung (4) und/oder von einem Elastomerkörper (3) umgeben sein.
Abstract:
A bed (10) is provided for supporting a patient thereon. Bed (10) includes a first bed component (14) that is movable relative to a second bed component (16). Bed (10) further includes a position detector (18) configured to detect the position of second bed component (16) relative to first bed component (14).
Abstract:
A flexible microbend device for attachment to an optical fiber is provided. The device comprises an upper bending element grid having at least one flexible element and a lower bending element grid having at least one flexible element. The upper bending element grid alternately engages the lower bending element grid. The flexible microbend device is attached to an optical fiber to form a sensor. The sensor may be either embedded in a host material or attached to a structure to detect various stresses or strains.
Abstract:
The invention concerns an optical fibre sensor (14) for measuring stress exerted on a substrate, comprising a support (1) bearing a multimode optical fibre (14) wherein transmitted light is attenuated when the fibre (14) bending or microbending angle (16) is modified by the effect of the stress applied, said support (1) having high and lesser stress zones when it is bent to adapt itself to the curved substrate whereon it is set. The invention is characterised in that the support (1) bearing the optical fibre (14) has a periodic array of perforations (12) wherein the optical fibre (14) is threaded, the period and cyclic ratio of the fibre (14) microbending (16) remaining constant, said perforations (12) being provided in the support (1) high stress zones along preferred axes defined by said support (1) intersection with a plane containing the bending radius (R) and perpendicular to said support (1) bending radius, and said perforations (12) being provided along non-preferred axes in the support lesser stress zones.
Abstract:
The device comprises a series of segments (2a, 2b, 2c) of measurement optical fibre (2) and a series of segments (3a, 3b) of strain fibre (3) extending transversaly to the longitudinal direction of the segments of measurement optical fibre; the segments of strain fibre are alternately arranged on either side of the segments of measurement optical fibre; the fibre segments of at least one series are covered with a protection member (4) providing for a relative displacement of the protection member and the coated fibre segments.
Abstract:
Pressure sensitive optical fiber (11) having core means (15), at least a portion of which has a predetermined refractive index for transmitting light therethrough, cladding means adjacent the core means having a refractive index which is less than that of the core means, and concentric light transmissive means (22) adjacent the cladding means having refractive index which is greater than that of the cladding means and through which light passes in proportion to the amount of stress or strain induced in the fiber. Also, pressure sensors and methods for measuring forces or perturbations utilizing such fiber.
Abstract:
Optical device and method for strain detection. The device comprises at least one optical fiber (1) arranged so as to form a network (2). Light emitting means (E) arranged at one end of the fiber and receiver means (R) arranged at the other end enable to supply an information relative to the light intensity transmitted by the fiber or fibers in the presence of strain and a measurement corresponding to said strain. Application to weighing apparatus and pressure chart takings.