Fiber optic detector and depth sensor and method for doing same
AssigneeBoard of Control of Michigan Technological University
InventorsLawrence W. Evers, Kenneth J. Jackson
Life of this patent
Estimating the term…
Abstract
A fiber optic sensor for determining the presence and/or measuring the depth of a first substance capable of transmitting light. The fiber optic sensor includes a plurality of light receiving fibers, a plurality of light transmitting fibers surrounding the light receiving fibers and structure for refracting light from the light transmitting fibers at a predetermined angle for total internal reflection of the light from an interface of the first substance with a second substance.
Claims28
A fiber optic fluid depth sensor for measuring the depth a fluid interfacing with a second substance, said sensor comprising:
- a plurality of light receiving fibers;
- a plurality of light transmitting fibers;
- means for transmitting light to said light transmitting fibers;
- and
- means for refracting light from said light transmitting fibers at a predetermined angle so that light striking the interface of the fluid with the second substance will be totally internally reflected and received by said light receiving fibers.
A method of measuring the depth of a fluid using a fiber optic fluid depth sensor, said method comprising the steps of:
- surrounding a plurality of light receiving fibers with a plurality of light transmitting fibers in a fiber optic fluid depth sensor;
- disposing the fiber optic fluid depth sensor in a first fluid;
- transmitting light from a light source through the transmitting fibers;
- refracting light from the transmitting fibers at a predetermined angle toward an interface between the first fluid and a second fluid;
- reflecting light from the interface at an angle equal to or greater than a critical angle of the first and second fluids;
- and
- receiving the reflected light with the receiving fibers which receive the light by total internal reflection from the interface.
A method of measuring the depth of a fluid using a fiber optic fluid depth sensor, said method comprising the steps of:
- surrounding a means of light receiving fibers with a plurality of light transmitting fibers in a fiber optic fluid depth sensor;
- disposing fiber optic fluid depth sensor in a first fluid;
- transmitting light from a light source through the transmitting fibers;
- refracting light from the transmitting fibers at a predetermined angle toward an interface between the first fluid and a second fluid;
- reflecting light from the interface at an angle equal to or greater than a critical angle of the first and second fluids;
- and
- receiving the reflected light with the receiving fibers which transmit the light by total internal reflection;
- converting the light received by the receiving fibers into an electrical current;
- converting the electrical current into an electrical voltage;
- and
- comparing the electrical voltage to a calibrated curve for voltage output versus depth to determine the depth of the fluid measured.
A method of determining the presence of a first substance on a surface using a fiber optic sensor, said method comprising the steps of:
- surrounding a plurality of light receiving fibers with a plurality of light transmitting fibers in a fiber optic sensor;
- disposing the fiber optic sensor in the surface;
- transmitting light from a light source through the transmitting fibers;
- refracting light from the transmitting fibers at a predetermined angle so that light strikes any interface that may be present between the first substance and a second substance at an angle equal to or greater than a critical angle for the first and second substances;
- reflecting light from the interface if the first substance is present;
- and
- receiving the reflected light with the light receiving fibers.
A fiber optic sensor for detecting the presence of a first substance, said sensor comprising:
- a plurality of light receiving fibers;
- a plurality of light transmitting fibers;
- means for transmitting light to said light transmitting fibers;
- and
- means for refracting light from said light transmitting fibers at a predetermined angle toward any interface of the first substance and a second substance whereby if the first substance is present, light from the interface is totally internally reflected by the interface and received by the light receiving fibers.
A fiber optic depth sensor for measuring the depth of a first substance interfacing with a second substance, said sensor comprising:
- a plurality of light receiving fibers;
- a plurality of light transmitting fibers;
- means for transmitting light to said light transmitting fibers;
- and
- means for refracting light from said light transmitting fibers at a predetermined angle so that light striking the interface of the first substance with the second substance will be totally internally reflected and received by said light receiving fibers.
A method of measuring the depth of a substance, said method comprising the steps:
- supplying a plurality of light transmitting fibers;
- supplying a plurality of light receiving fibers;
- transmitting light from a light source through the light transmitting fibers;
- refracting light exiting the light transmitting fibers at a predetermined angle;
- transmitting the refracted light through the depth of the substance;
- reflecting the light that travels through the substance when the light strikes an interface between the substance and a second substance;
- receiving the reflected light with the light receiving fibers;
- calculating the depth of the substance based upon the amount of light received by the light receiving fibers.
Dependencies are inferred from the claim text.