Liquid crystal non-destructive inspection of non-ferrous metals

Claim 1

A method for detecting the presence of physical defect flaws in work area surface and subsurface portions of a nominally uniform electrically bulk conductive non-ferrous workpiece comprising the steps of: coloring the work area surface of said workpiece to provide an optical contrast background; disposing a suspension of liquid crystal particles over said optical contrast background located in contiguum with said work area surface of said electrically bulk conductive non-ferrous workpiece; establishing an electrical potential difference across said workpiece work area surface to establish an electrical current flow through said workpiece in a direction substantially parallel with said work area surface, a portion of said potential difference being perturbed from a uniform potential change pattern across each of said physical defect flaws; illuminating said work area liquid crystal suspension with visible spectrum optical energy; and visually inspecting the optical image reflected by said liquid crystal suspension and said optical contrast background for said electric potential pattern induced liquid crystal pattern perturbations, said perturbations thereby identifying said work area surface and subsurface defects.

Claim 2

A method for detecting the presence of physical defect flaws in work area surface and subsurface portions of a nominally uniform electrically bulk conductive non-ferrous workpiece comprising the steps of: coloring the work area surface of said workpiece to provide an optical contrast background; disposing a suspension of liquid crystal particles over said optical contrast background located in contiguum with said work area surface of said electrically bulk conductive non-ferrous workpiece; establishing an electrical potential difference across said workpiece work area surface to establish an electrical current flow through said workpiece in a direction substantially parallel with said work area surface, a portion of said potential difference being perturbed from a uniform potential change pattern across each of said physical defect flaws; illuminating said work area liquid crystal suspension with visible spectrum optical energy; and visually inspecting the optical image reflected by said liquid crystal suspension and said optical contrast background for said electric potential pattern induced liquid crystal pattern perturbations, said perturbations thereby identifying said work area surface and subsurface defects.

Claim 13

A method for detecting surface defects in a work area surface of a homogeneous electrically conductive non-ferrous metallic workpiece comprising the steps of: coloring the to-be-inspected work area surface of said homegeneous metallic non-ferrous workpiece with an optical contrast material of a first color; attaching a first electrode to said work member in a location adjacent one boundary of said work area surface; connecting a second electrode to said work member in a location adjacent an opposite boundary of said work area surface; establishing an electrical direct current flow between said first and second electrodes in said homogeneous workpiece, said current flow traversing said work area surface and flowing along a workpiece path parallel thereto. covering said colored work area surface with a liquid crystal suspension layer capable of transmitting optical energy to and from said optical contrast material in a first electric field responsive crystal alignment state thereof and of reflecting second color optical energy in a second electric field absent crystal alignment state thereof; illuminating said work area surface and said liquid crystal suspension layer with visible spectrum optical energy from an optical source of the elevated energy state type; and visually examining a magnified optical image from said illuminated liquid crystal suspension layer for electric potential gradient change responsive discontinuities involving said first and second colors.

Claim 14

A method for detecting surface defects in a work area surface of a homogeneous electrically conductive non-ferrous metallic workpiece comprising the steps of: coloring the to-be-inspected work area surface of said homegeneous metallic non-ferrous workpiece with an optical contrast material of a first color; attaching a first electrode to said work member in a location adjacent one boundary of said work area surface; connecting a second electrode to said work member in a location adjacent an opposite boundary of said work area surface; establishing an electrical direct current flow between said first and second electrodes in said homogeneous workpiece, said current flow traversing said work area surface and flowing along a workpiece path parallel thereto. covering said colored work area surface with a liquid crystal suspension layer capable of transmitting optical energy to and from said optical contrast material in a first electric field responsive crystal alignment state thereof and of reflecting second color optical energy in a second electric field absent crystal alignment state thereof; illuminating said work area surface and said liquid crystal suspension layer with visible spectrum optical energy from an optical source of the elevated energy state type; and visually examining a magnified optical image from said illuminated liquid crystal suspension layer for electric potential gradient change responsive discontinuities involving said first and second colors.