Methods and apparatus for determining fibre orientation
AssigneeUniversity of Northern British Columbia
InventorsMatthew E. Reid, Robert Fedosejevs
Life of this patent
Estimating the term…
Abstract
Fibre distribution characteristics such as the bulk average orientation of fibres in composite fibrous materials can be evaluated based on the variation in the speed with which polarized electromagnetic signals propagate through the material as a function of angle. The electromagnetic radiation may comprise terahertz radiation. The composite fibrous materials may be wood-containing materials such as oriented strand board or particle board.
Claims27
A method for measuring average orientations of fibres in a composite fibrous material, the method comprising:
- passing first electromagnetic radiation through the material, the first electromagnetic radiation having a first polarization state and passing second electromagnetic radiation through the material, the second electromagnetic radiation having a second polarization state, the first and second electromagnetic radiation having one or more wavelengths at which the material is not opaque;
- detecting the first and second electromagnetic radiation that has passed though the material;
- and,
- obtaining a measure of birefringence of a sample at the wavelengths of the electromagnetic radiation based at least in part on the detected first and second electromagnetic radiation.
21-22. (canceled)
Apparatus for quality control in the manufacture of a composite fibrous material, the apparatus comprising:
- a source of THz radiation located to direct polarized THz radiation at a first face of a moving web of the composite fibrous material with a selected one of a plurality of polarization states;
- a detector of THz radiation located to receive the THz radiation originating from the source and emerging on a second face of the composite fibrous material;
- and,
- a controller connected to select a polarization state of the source and configured to operate the detector and obtain a measure of birefringence of the material at wavelengths of the THz radiation.
Dependencies are inferred from the claim text.