US 5,231,472 A · Color matching and characterization of surface coatings

Abstract

A method of characterization of a coating on a surface such as a paint coating having metallic flakes distributed within such coating. Single and multi-angle models are utilized. The coating is characterized by measurements having components of light reflected by the metal flakes and attenuated on its exit route from the coating, of light scattered in the entering path of the beam as it travels through the coating, of light scattered by the reflected beam on its exit from the coating, of light scattered in the entering path then reflected by the metallic flakes and attenuated in the coating on exiting, and of light scattering in the exit path, both to the metallic flake and reflected by the flake and attenuated on its exit from the coating. Methods of color matching a coating having a metallic flake distribution within the coating are included using reflectance factors and tristimulus values and minimizing the sum of the squares of the deviation between samples.

Claims23

Dependent claims

A method of characterization of a coating of a surface having metallic flakes distributed beneath a film within such coating, the method comprising the following steps:

(a) directing a beam or beams of light toward said coating;
(b) measuring the light leaving the coating from at least one predetermined angle from the outer surface of said coating;
(c) analyzing said measured light as a function of wavelength;
and
(d) characterizing said measured light as composed of the following components:
i. light from said beam reflected by said metal flake and attenuated on its exit route from the coating;
ii. light scattered in the entering path of the beam as it travels through the coating;
iii. light scattered by the reflected beam on its exit route from the coating;
iv. light scattered in the entering path then reflected by said metallic flake, and attenuated in the coating on the exiting path;
v. light scattered in the exiting path both to said metallic flake and reflected by said metallic flake and attenuated on its exit path from the coating.

7 more elements

A method of color matching a coating having metallic flakes distributed in a film on a sample comprising:

(a) directing a beam of light toward said coating;
(b) measuring the light leaving the coating from at least one predetermined angle from the outer surface of said coating;
(c) analyzing said measured light as a function of wavelength;
(d) calculating the light characteristics of said sample from said measured light based upon the radiance factor (.beta.) above where ##EQU88## in which .mu. is the direction cosine of the angle of reflection at a given azimuthal angle;
.phi. is the azimuthal angle of the reflected radiation;
.mu..sub.o is the direction cosine of the angle of incident beam at a given azimuthal angle;
.phi..sub.o is the azimuthal angle of the incident beam;
.sigma. is the cross section of said metallic flake;
r is the reflection coefficient of said metallic flake;
K is the absorption coefficient of said film;
S is the scattering coefficient of the film;
(e) formulating trial coatings having various concentrations of pigments;
and
(f) comparing the light characteristics of said trial coatings to said characteristics of said sample.

11 more elements

A method of color matching a coating having metallic flakes distributed in a film on a sample comprising:

(a) directing a beam of light toward said coating;
(b) measuring the light leaving the coating from at least one predetermined angle from the outer surface of said coating;
(c) analyzing said measured light as a function of wavelength;
(d) calculating the light characteristics of said sample from said measured light based upon the radiance factor (.beta.) above where ##EQU89## in which .mu. is the direction cosine of the angle of reflection at a given azimuthal angle;
.phi. is the azimuthal angle of the reflected radiation;
.mu..sub.o is the direction cosine of the angle of incident beam at a given azimuthal angle;
.phi..sub.o is the azimuthal angle of the incident beam;
.sigma. is the cross section of said metallic flake;
r is the reflection coefficient of said metallic flake;
K is the absorption coefficient of said film;
S is the scattering coefficient of the film;
(e) formulating trial coatings having various concentrations of pigments;
and
(f) comparing the light characteristics of said trial coatings to said characteristics of said sample.

11 more elements

A method of color matching a coating having metallic flakes distributed in a film on a sample comprising:

(a) directing a beam of light toward said coating;
(b) measuring the light leaving the coating from at least one predetermined angle from the outer surface of said coating;
(c) analyzing said measured light as a function of wavelength;
(d) calculating the light characteristics of said sample from said measured light based upon radiance factor (.beta.) above where ##EQU90## in which .omega..sub.o is the albedo of said metallic flake;
.mu. is the direction cosine of the angle of reflection at a given azimuthal angle;
.phi. is the azimuthal angle of the reflected radiation;
.mu..sub.o is the direction cosine of the angle of incident beam at a given azimuthal angle;
.phi..sub.o is the azimuthal angle of the incident beam;
.sigma. is the cross section of said metallic flake;
r is the reflection coefficient of said metallic flake;
K is the absorption coefficient of said film;
S is the scattering coefficient of the film;
(e) formulating trial coatings having various concentrations of pigments;
and
(f) comparing the light characteristics of said trial coatings to said characteristics of said sample.

12 more elements

Dependencies are inferred from the claim text.

Color matching and characterization of surface coatings

Life of this patent

Color matching and characterization of surface coatings

Life of this patent

Abstract

Claims23