US 2006/0221334 A1 · METHOD OF MAKING A STANDARD TOOL FOR CALIBRATING STRESS ANALYSIS MEASURING DEVICES AND A SET OF THE STANDARD TOOLS

Abstract

A method of making a standard tool for calibrating polarimeters that analyze stress in photoelastic material, includes the steps of partially annealing a starting piece of tempered glass so that the starting piece has a retardance below 250 nm/cm, removing a peripheral portion of the starting piece (preferably, at least about 20% of its radial dimension) to leave a working piece, cutting a rectangular parallelepiped from the working piece, polishing two opposing faces of the rectangular parallelepiped where the two opposing faces are spaced apart by a measurement distance through which light passes during stress analysis in a polarimeter, and determining a birefringence of the rectangular parallelepiped across the measurement distance using a calibrated polarimeter. The standard tool is the rectangular parallelepiped having the determined birefringence for the measurement distance. The method can be used to make a set of the standard tools with different measurement distances.

Claims18

Dependent claims

A method of making a standard tool for calibrating devices that analyze stress in photoelastic material, the method comprising the sequential steps of:

partially annealing a starting piece of tempered glass, the starting piece having a first thickness and a first surface with a first dimension that is perpendicular to the first thickness;
removing a peripheral portion of the partially annealed starting piece to leave a working piece having the first thickness and a second dimension less than the first dimension;
cutting a rectangular parallelepiped from the working piece;
polishing two opposing faces of the rectangular parallelepiped, the two opposing faces being spaced apart by a measurement distance through which light passes during stress analysis in a stress analysis device, the two opposing faces being perpendicular to the first surface;
and
determining a birefringence of the rectangular parallelepiped across the measurement distance using a calibrated stress analysis device, the rectangular parallelepiped being the standard tool that has the determined birefringence for the measurement distance.

3 more elements

A method of making a set of standard tools for calibrating a polarimeter, the method comprising the sequential steps of:

partially annealing a starting piece of tempered glass to the strain point of the glass so that the partially annealed starting piece has a retardance below 250 nm/cm, the starting piece having a first thickness and a first surface with a first dimension, the first thickness being perpendicular to said first surface;
removing a peripheral portion of the first surface to leave a working piece having the first thickness and a second dimension that is less than the first dimension;
cutting plural rectangular parallelepipeds from the working piece, each of the rectangular parallelepipeds having two opposing faces spaced apart by a different respective measurement distance through which light passes during stress analysis in a polarimeter, the two opposing faces being perpendicular to the first surface;
polishing the two opposing faces of the rectangular parallelepipeds;
and
determining a birefringence of each of the rectangular parallelepipeds, the rectangular parallelepipeds being the set of standard tools that have the respectively determined birefringence for the respective measurement distances.

3 more elements

Dependencies are inferred from the claim text.

Method of making a standard tool for calibrating stress analysis measuring devices and a set of the standard tools

Life of this patent

Method of making a standard tool for calibrating stress analysis measuring devices and a set of the standard tools

Life of this patent

Abstract

Claims18