Abstract: Systems and methods of performing a stress measurement of a chemically strengthened glass using a light-scattering polarimetry system include adjusting the intensity of a light beam from a light source in an illumination system using a rotatable half-wave plate and a first polarizer operably disposed between the light source and a rotating light diffuser that has a rotation time tR. The first polarizer is aligned with a second polarizer in a downstream optical compensator to have matching polarization directions by rotating the rotatable half-wave plate to a position where the exposure time tE falls within an exposure range tR?tE. The method also includes performing an exposure using the exposure time tE to obtain the stress measurement. One or both of the half-wave plate and first polarizer can be tilted to avoid deleterious back-reflected light from entering the light source.

Abstract: The hybrid measurement system includes an evanescent prism coupling spectroscopy (EPCS) sub-system and a light-scattering polarimetry (LSP) sub-system. The EPCS sub-system includes an EPCS light source system optically coupled to an EPCS detector system through an EPCS coupling prism. The LSP sub-system includes an LSP light source optically coupled to an optical compensator, which in turn is optically coupled to a LSP detector system via a LSP coupling prism. A support structure supports the EPCS and LSP coupling prisms to define a coupling prism assembly, which supports the two prisms at a measurement location. Stress measurements made using the EPCS and LSP sub-systems are combined to fully characterize the stress properties of a transparent chemically strengthened substrate. Methods of processing the EPCS and LSP measurements and enhanced configurations of the EPCS and LPS sub-systems to improve measurement accuracy are also disclosed.

Abstract: Apparatus can comprise a cavity at least partially defined by a first major surface of a reference block and configured to receive a sample. The apparatus can comprise a first polarization-switching light source configured to emit a first polarization-switched light beam toward the cavity and a first detector configured to detect a corresponding signal. The apparatus can comprise a second polarization-switching light source configured to emit a second polarization-switched light beam toward the cavity and a second detector configured to detect a corresponding signal. The first reference block can be positioned between the second detector and the second reference block. Methods of determining an estimated stress profile can comprise determining a central tension from a measured retardation profile of the sample. Methods can comprise determining an initial stress profile from a refractive index profile of the sample. Methods can comprise scaling and adjusting stress profiles.

Abstract: Systems and methods of performing a stress measurement of a chemically strengthened glass using a light-scattering polarimetry system include adjusting the intensity of a light beam from a light source in an illumination system using a rotatable half-wave plate and a first polarizer operably disposed between the light source and a rotating light diffuser that has a rotation time tR. The first polarizer is aligned with a second polarizer in a downstream optical compensator to have matching polarization directions by rotating the rotatable half-wave plate to a position where the exposure time tE falls within an exposure range tR?tE. The method also includes performing an exposure using the exposure time tE to obtain the stress measurement. One or both of the half-wave plate and first polarizer can be tilted to avoid deleterious back-reflected light from entering the light source.

Abstract: The hybrid measurement system includes an evanescent prism coupling spectroscopy (EPCS) sub-system and a light-scattering polarimetry (LSP) sub-system. The EPCS sub-system includes an EPCS light source system optically coupled to an EPCS detector system through an EPCS coupling prism. The LSP sub-system includes an LSP light source optically coupled to an optical compensator, which in turn is optically coupled to a LSP detector system via a LSP coupling prism. A support structure supports the EPCS and LSP coupling prisms to define a coupling prism assembly, which supports the two prisms at a measurement location. Stress measurements made using the EPCS and LSP sub-systems are combined to fully characterize the stress properties of a transparent chemically strengthened substrate. Methods of processing the EPCS and LSP measurements and enhanced configurations of the EPCS and LPS sub-systems to improve measurement accuracy are also disclosed.

Abstract: The hybrid measurement system includes an evanescent prism coupling spectroscopy (EPCS) sub-system and a light-scattering polarimetry (LSP) sub-system. The EPCS sub-system includes an EPCS light source optically coupled to an EPCS detector system through an EPCS coupling prism. The LSP sub-system includes an LSP light source optically coupled to an optical compensator, which in turn is optically coupled to a LSP detector system via a LSP coupling prism. A support structure supports the EPCS and LSP coupling prisms to define a coupling prism assembly, which supports the two prisms at a measurement location. Stress measurements made using the EPCS and LSP sub-systems are combined to fully characterize the stress properties of a transparent chemically strengthened substrate. Methods of processing the EPCS and LSP measurements to improve measurement accuracy are also disclosed.

Abstract: Methods of characterizing an optical retardance or a stress-related property of a glass-bases sample include directing a light beam into the glass-based sample while varying the polarization of the light beam to generate scattered light for each polarization are provided. The scattered light for each polarization is captured with an image sensor, which has an exposure time and a frame rate. The scattered light has an intensity distribution at the image sensor. The sample is moved so that the image sensor averages two or more different intensity distributions per frame to form an averaged intensity distribution for each polarization. The averaged intensity distributions for multiple frames are then used to characterize the optical retardance. The optical retardance can turn be used to determine stress-related properties of the glass-based sample. Moving the substrate reduces measurement noise scattered light having no optical retardance information.

Abstract: Apparatus can comprise a cavity at least partially defined by a first major surface of a reference block and configured to receive a sample. The apparatus can comprise a first polarization-switching light source configured to emit a first polarization-switched light beam toward the cavity and a first detector configured to detect a corresponding signal. The apparatus can comprise a second polarization-switching light source configured to emit a second polarization-switched light beam toward the cavity and a second detector configured to detect a corresponding signal. The first reference block can be positioned between the second detector and the second reference block. Methods of determining an estimated stress profile can comprise determining a central tension from a measured retardation profile of the sample. Methods can comprise determining an initial stress profile from a refractive index profile of the sample. Methods can comprise scaling and adjusting stress profiles.

Abstract: Provided herein are systems and methods for monitoring radial stresses in glass tubing. In some embodiments, a measurement system includes a light source delivering a light to a tube, and a polarizer receiving the light after the light is refracted through a wall of the tube. The measurement system may further include a detector receiving the light from the polarizer, the detector operable to capture a first image of the light at a first polarization state and a second image of the light at a second polarization state. The system may further include a controller operable to determine a retardation profile related to the stress profile of the wall of the tube by determining a retardation magnitude of the light refracted through the wall of the tube based on a difference between the first image of the light and the second image of the light.

Abstract: The hybrid measurement system includes an evanescent prism coupling spectroscopy (EPCS) sub-system and a light-scattering polarimetry (LSP) sub-system. The EPCS sub-system includes an EPCS light source optically coupled to an EPCS detector system through an EPCS coupling prism. The LSP sub-system includes an LSP light source optically coupled to an optical compensator, which in turn is optically coupled to a LSP detector system via a LSP coupling prism. A support structure supports the EPCS and LSP coupling prisms to define a coupling prism assembly, which supports the two prisms at a measurement location. Stress measurements made using the EPCS and LSP sub-systems are combined to fully characterize the stress properties of a transparent chemically strengthened substrate. Methods of processing the EPCS and LSP measurements to improve measurement accuracy are also disclosed.

Abstract: Methods of characterizing an optical retardance or a stress-related property of a glass-bases sample include directing a light beam into the glass-based sample while varying the polarization of the light beam to generate scattered light for each polarization are provided. The scattered light for each polarization is captured with an image sensor, which has an exposure time and a frame rate. The scattered light has an intensity distribution at the image sensor. The sample is moved so that the image sensor averages two or more different intensity distributions per frame to form an averaged intensity distribution for each polarization. The averaged intensity distributions for multiple frames are then used to characterize the optical retardance. The optical retardance can turn be used to determine stress-related properties of the glass-based sample. Moving the substrate reduces measurement noise scattered light having no optical retardance information.

Abstract: Provided herein are systems and methods for monitoring radial stresses in glass tubing. In some embodiments, a measurement system includes a light source delivering a light to a tube, and a polarizer receiving the light after the light is refracted through a wall of the tube. The measurement system may further include a detector receiving the light from the polarizer, the detector operable to capture a first image of the light at a first polarization state and a second image of the light at a second polarization state. The system may further include a controller operable to determine a retardation profile related to the stress profile of the wall of the tube by determining a retardation magnitude of the light refracted through the wall of the tube based on a difference between the first image of the light and the second image of the light.

Abstract: Disclosed herein are glass-based articles having a first surface having an edge, wherein a maximum optical retardation of the first surface is at the edge and the maximum optical retardation is less than or equal to about 40 nm and wherein the optical retardation decreases from the edge toward a central region of the first surface, the central region having a boundary defined by a distance from the edge toward a center point of the first surface, wherein the distance is ½ of the shortest distance from the edge to the center point.

Abstract: Disclosed herein are glass-based articles having a first surface having an edge, wherein a maximum optical retardation of the first surface is at the edge and the maximum optical retardation is less than or equal to about 40 nm and wherein the optical retardation decreases from the edge toward a central region of the first surface, the central region having a boundary defined by a distance from the edge toward a center point of the first surface, wherein the distance is ½ of the shortest distance from the edge to the center point.

Abstract: A strengthened glass or glass ceramic sheet has a first major surface, a second major surface opposite the first major surface, an interior region between the first and second surfaces, an outer edge surface extending between the first and second major surfaces, and a thickness between the first major surface and the second major surfaces, wherein the sheet comprises a glass or glass ceramic and is thermally strengthened and wherein the first major surface has a roughness of more than 0.1 nm Ra and less than 500 nm Ra over an area of 10 ?m×10 ?m and wherein PP<0.

Abstract: Disclosed herein are glass-based articles having a first surface having an edge, wherein a maximum optical retardation of the first surface is at the edge and the maximum optical retardation is less than or equal to about 40 nm and wherein the optical retardation decreases from the edge toward a central region of the first surface, the central region having a boundary defined by a distance from the edge toward a center point of the first surface, wherein the distance is ½ of the shortest distance from the edge to the center point.

Abstract: Optical inspection systems and methods for inspecting a glass sheet for defects are disclosed. The systems and methods employ a digital camera and a plurality of different types of illumination sources. The object plane of the digital camera moves through the glass sheet body while flash exposures from one or more of the illumination sources are performed. The movement occurs during a ready-to-acquire time of the digital camera. This allows the digital camera to capture a plurality of digital inspection images on the fly at different exposure positions within the glass sheet body without waiting for any digital image processing to occur. The digital inspection images are then reviewed to characterize any revealed defects.

Abstract: Optical inspection system and methods for detecting surface discontinuity defects in glass sheet are disclosed. A reflective diffuser resides adjacent a back surface of the glass sheet and is illuminated with gradient intensity illumination. A digital camera having a two-dimensional image sensor resides adjacent the front surface of the glass sheet. The digital camera has, at the reflective diffuser, an acceptance circle that shifts relative to the gradient illumination due to the surface discontinuity. The shift causes the digital inspection image to change intensity, and the change is faster than if the illumination of the reflective diffuser had uniform intensity.

Abstract: Optical inspection systems and methods for inspecting a glass sheet for defects are disclosed. The systems and methods employ a digital camera and a plurality of different types of illumination sources. The object plane of the digital camera moves through the glass sheet body while flash exposures from one or more of the illumination sources are performed. The movement occurs during a ready-to-acquire time of the digital camera. This allows the digital camera to capture a plurality of digital inspection images on the fly at different exposure positions within the glass sheet body without waiting for any digital image processing to occur. The digital inspection images are then reviewed to characterize any revealed defects.