Measuring and testing – Specimen stress or strain – or testing by stress or strain... – By loading of specimen
Patent
1989-07-11
1991-05-07
Myracle, Jerry W.
Measuring and testing
Specimen stress or strain, or testing by stress or strain...
By loading of specimen
356 32, G01L 124
Patent
active
050126792
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The invention relates to an optical sensor including at least one fibre-type light wave guide changing its light transmitting characteristics in dependence on the influence of a parameter, in particular a force, a pressure or the like, these changes being used for measuring the parameter.
In the article "Faseroptische Sensoren," R. Kist in the Journal "Technisches Messen," June 1984, various applications of fibre-type light wave guides in the measuring field are disclosed and the advantages of such fibre-optical sensors are explained in detail. To be noted are the extraordinary high resolution, the simple design due to the omission of transducers and the direct digital capturing and processing of the measured signals. In this connection fibre-optical sensors are divided into multiple-wave (multimode) fibres where the measured parameter affects the intensity, the frequency or the propagation time of a light signal, and into single-wave (singlemode) fibres where predominantly the amplitude, phase and/or polarisation of the light signal is evaluated for the measurement.
The known developments restrict essentially to laboratory tests. Thus, for example, a light wave guide was immersed into liquids for measuring parameters thereof. German Patent Specification No. 35 41 733 discloses, furthermore, to metallically coat a fibre and to fix it to a carrier structure by welding or galvanically embedding. As mentioned in detail in the publication, the adherence and the temperature resistivity of such an application technique is not uncritical.
It is the object of the invention to provide a fibre-optical sensor being relatively insensitive against exterior influences and capable of being manufactured simply while having a high measuring accuracy.
By embedding the fibre-type light wave guide it is wellprotected against mechanical and chemical influences. Since the layer material completely transmits forces or pressures, respectively, to the light wave guide the measuring accuracy is relatively high.
Preferred embodiments of the optical sensor according to the invention are characterized in the subclaims.
Further features and advantages of the optical sensor according to the invention will be apparent from the following description of embodiments with reference to the drawing. There are shown
FIG. 1 a schematical diagram for explaining the principle of the optical sensor according to the invention,
FIG. 2 a plan view of a first embodiment of an optical sensor according to the invention,
FIG. 3 a schematic elevational view of the optical sensor according to FIG. 2 in section,
FIG. 4 a plan view of a further embodiment of the sensor according to the invention,
FIG. 5 an elevational view of the sensor according to FIG. 4,
FIG. 6 embodiment of another type of optical sensor according to the invention in section,
FIG. 7 a plan view of an essential part of the sensor according to FIG. 6,
FIG. 8 an embodiment of an optical sensor according to the invention modified as compared with that FIG. 6 in section,
FIG. 9 a force measuring carpet using optical sensors connected optically in series,
FIG. 10 a particularly preferred light wave guide combination,
FIG. 11 a two-beam interferometer according to Mach-Zehnder in a different embodiment,
FIGS. 12a-12j various embodiments of optical force-measuring sensors where the light wave guides are applied to various elastically deformable bodies, and
FIGS. 13a, 13b a specific embodiment of an optical force-measuring sensor according to the invention in two elevational views.
In FIG. 1, the principle of an optical sensor according to the invention is illustrated as an example, functioning as a so-called Mach-Zehnder sensor.
Light from a monochromatic light source 1, such as a laser diode, is applied through a polarizer 2 to a coupler 4a for splitting the light to a measuring light wave guide 3a and a reference light wave guide 3b. The light exiting from the two light wave guides 3a,3b is applied to a further coupler 4b, is detected in photoelectric elements 5, the electrical out
REFERENCES:
patent: 4560016 (1985-12-01), Ibanez et al.
patent: 4671659 (1987-06-01), Rempt et al.
patent: 4814562 (1989-03-01), Langston
First International Conference on Optical Fibre Sensors, 26-28 Apr. 1983, S. C. Rashleigh: "Polarimetric Sensors Exploiting the Axial Stress in High Bi-Refringence Fibers", pp. 210-213.
Journal "Technisches Messen", June 1984, "Faseroptische Sensoren", R. Kist, pp. 19.1-19.6.
Myracle Jerry W.
Pfister GmbH
LandOfFree
Optical sensor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Optical sensor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical sensor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-932139