Method for measuring the fibre orientation anisotropy in a...

G - Physics – 01 – N

Patent

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

G01N 21/84 (2006.01) G01N 21/21 (2006.01) G01N 21/41 (2006.01)

Patent

CA 2051977

18 ABSTRACT A method and a device for the non destructive measurement of the fibre orientation anisotropy in a fibrous structure. The method relies on the difference of refractive indices for light beams polarized in two perpendicular directions to measure the value of the anisotropy on the surface of a fibrous structure. Because the use of an infrared light, with a wavelength in the 9 to 11 µm spectral range, the penetration depth of the light is of the order of a few tenths of microns and the fibrous structure shows a large birefringence directly associated with the fibre orientation anisotropy. This birefringence can be measured as a difference in the refractive indices of the fibrous structure in two different directions. A light beam produced with an infrared light source, such as a CO2 laser, is modulated by a chopper, linearly polarized and sent to a photoelastic modulator which varies the state of polarization of the light at a given frequency. After directing the modulated light towards the surface of the fibrous structure, the light is reflected and polarized again. The intensity of the second harmonic and the total intensity of the reflected polarized beam is measured according to a plurality of angles of incidence. These angles are obtained by the rotation of the sample platform parallel to the plane of incidence. The angles of incidence at the minimum ratio between the intensity of the second harmonic and the total intensity (Brewster's angle) are calculated for two different orientations and the fibre orientation anisotropy is determined by subtracting the two Brewster's angles: the higher is the difference between the Brewster's angles, the higher is the fibre orientation anisotropy. The average refractive index is obtained from the mean value between the Brewster's angles.

LandOfFree

Say what you really think

Search LandOfFree.com for Canadian inventors and patents. Rate them and share your experience with other people.

Rating

Method for measuring the fibre orientation anisotropy in a... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method for measuring the fibre orientation anisotropy in a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for measuring the fibre orientation anisotropy in a... will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFCA-PAI-O-1439343

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.