Title:
METHOD FOR DETECTING RUGGEDNESS OF MAGNETIC METAL PLATE
Document Type and Number:
Japanese Patent JPH03221804
Kind Code:
A
Abstract:
PURPOSE:To rapidly and easily detect the ruggedness of a metal plate from the rotational angle of a polarization face of reflected light reflected from a substance having a pole Kerr effect by making a spot-like straight polarized light incident upon the substance so as to sweep its surface. CONSTITUTION:A magnetic field is impressed in the direction parallel with the surface of the magnetic metal plate 1 by using a permanent magnet 2 and a york 3 having high magnetic permeability in order to detect a recessed part 10 on the surface of the plate 1. In the vicinity of the recessed part 10, a leaked magnetic field 11 is distributed on the surface and an iron thin film 6 is formed on a non-magnetic base 5 in the vicinity of the magnetic field 11. The thin film 6 is magnetized by the magnetic field 11 and allowed to have the pole Kerr effect. Then, straight polarized light 8 is made incident from a polarizing light source 7 to the thin film 6 and the rotational angle of the polarized face of the reflected light is detected by a photodetector 9. Consequently, the size of the leaked magnetic field, i.e. the existence and size of a rugged part, can be known. Since the incident straight polarized light is like a spot, the magnetic field can be locally measured and the wide distribution of the leaked magnetic field can be known by sweeping the spot on the thin film 6.
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Inventors:
WASA YASUHIRO
Application Number:
JP1751190A
Publication Date:
September 30, 1991
Filing Date:
January 26, 1990
Export Citation:
Assignee:
NEC CORP
International Classes:
G01B7/34; G01B7/00; G01B11/30; (IPC1-7): G01B7/34; G01B11/30
Attorney, Agent or Firm:
Sugano Naka
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