Sensing of material of construction and color of containers

Apparatus for analyzing the character of a light transmitting container, comprising:

• a container support adapted for supporting a container;
• a first source of a beam of light of a first wavelength disposed to direct the beam of light through the container supported in the container support;
• a second source of a beam of light of a second wavelength disposed to direct the beam of light through the container supported in the container support, the first source and the second source being disposed so that the beam of light of the first wavelength and the beam of light of the second wavelength are at least in part parallel and coincident on a beam path;
• a first polarizer disposed in the beam path at a location prior to passage of the beams through the container;
• a beam controller that controls the operation of the first light source and the second light source to operate in an alternating fashion.
• a light analyzer having
• a parallel polarizer relative to the polarization of the light from the first polarizer, the parallel polarizer being disposed to intercept a first portion of the beam path at a location after the beams have passed through the container,
• a cross polarizer relative to the polarization of the light from the first polarizer, the cross polarizer being disposed to intercept a second portion of the beam path at a location after the beams have passed through the container,
• a first detector that measures the intensity of a light beam, the first detector being disposed to detect the light passing through the parallel polarizer, and
• a second detector that measures the intensity of a light beam, the second detector being disposed to detect the light passing through the cross polarizer;
• and
• means for analyzing the character of the container using the intensities measured by the light analyzer.

Apparatus for determining whether a container is formed of glass or an optically active plastic, comprising:

• a container support adapted for supporting a container of an unknown, but optically transmissive material;
• a source of a beam of light disposed to direct the beam of light through the container supported in the container support;
• a first polarizer disposed in the beam path at a location prior to passage of the beam through the container;
• a light analyzer having
• a parallel polarizer relative to the polarization of the light from the first polarizer, the parallel polizer being disposed to intercept a first portion of the beam at a location after the beam has passed through the container,
• a cross polarizer relative to the polarization of the light from the first polarizer, the cross polarizer being disposed to intercept a second portion of the beam at a location after the beam has passed through the container,
• a first detector that measures the intensity of a light beam, the first detector being disposed to detect the light passing through the parallel polarizer, and
• a second detector that measures the intensity of a light beam, the second detector being disposed to detect the light passing through the cross polarizer;
• and
• means for determining the difference of the intensity measured by the first detector and the intensity measured by the second detector.

Apparatus for determining the color of a container that is transmissive to light, comprising:

• a container support adapted for supporting a container;
• a first source of a beam of light of a first wavelength disposed to direct the beam of light through the container supported in the container support;
• a second source of a beam of light of a second wavelength disposed to direct the beam of light through the container supported in the container support;
• a first light analyzer having
• a first detector that measures the intensity of a light beam, the first detector being disposed to detect the intensity of the beam from the first source, after the beam has passed through the container, and
• a second detector that measures the intensity of a light beam, the second detector being disposed to detect the intensity of the beam from the second source, after the beam has passed through the container;
• and
• means for determining the difference of the intensities measured by the first detector and the second detector.

Apparatus for determining the color of a container that is transmissive to light, comprising:

• a container support adapted for supporting a container;
• a first source of a beam of light of a first wavelength disposed to direct the beam of light through the container supported in the container support;
• a second source of a beam of light of a second wavelength disposed to direct the beam of light through the container supported in the container support, the first source and the second source being disposed so that the beam of light of the first wavelength and the beam of light of the second wavelength are at least in part parallel and coincident on a beam path;
• a beam controller that controls the operation of the first light source and the second light source to operate in an alternating fashion;
• a light analyzer having a detector that measures the intensity of a light beam, the detector being disposed to detect the intensity of the coincident beam;
• and
• means for determining the difference of the intensity measured by the detector when the first source is operating and the intensity measured by the detector when the second source is operating.

A process for determining whether a container is formed of glass or an optically active plastic, comprising the steps of:

• finding a polarization difference index for the container, utilizing the steps of
• passing a beam of polarized light through a container,
• passing a portion of the beam through a parallel polarizer, after it has passed through the container,
• passing another portion of the beam through a cross polarizer, after it has passed through the container, and
• determining the polarization difference index as the difference in intensity of the portion of the beam passed through the parallel polarizer and the intensity of the portion of the beam passed through the cross polarizer;
• repeating the step of finding with no container present;
• and
• comparing the polarization difference index determined with a container present and with no container present.

A process for determining the color components of a container that is at least partly transparent to light, comprising the steps of:

• transmitting a beam of light through the container, the beam having at least two different wavelengths therein;
• measuring the intensity of the transmitted beam at the two different wavelengths;
• and
• calculating a normalized color index of the container as the difference between the intensities of the beam at the two different wavelengths divided by the sum of the intensities of the beam at the two different wavelengths.

A process for characterizing the nature of a container that is at least partially transparent to light, comprising the steps of:

• transmitting the beam of light through the container, the beam having at least two different wavelengths therein;
• measuring the intensity of the transmitted beam at the two different wavelengths;
• calculating a color index of the container as the difference between the intensities of the beam at the two different wavelengths.
• finding a polarization difference index for the container, utilizing the steps of
• passing a beam of polarized light through a container,
• passing a portion of the beam through a parallel polarizer, after it has passed through the container,
• passing another portion of the beam through a cross polarizer, after it has passed through the container, and
• determining the polarization difference index as the difference in intensity of the portion of the beam passed through the parallel polarizer and the intensity of the portion of the beam passed through the cross polarizer;
• repeating the step of finding with no container present;
• and
• comparing the polarization difference index determined with a container present and with no container present.