Non-destructive stress profile determination in chemically tempered glass
First Claim
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1. An apparatus comprising:
- a polarimetric optical coherence tomography device configured to use ultrashort polarized probe pulses to analyze with depth resolution of about one micron or finer a cover glass having a residual stress depth profile;
a fixture configured to align the cover glass in an optical coupling with the ultrashort polarized probe pulses of the polarimetric optical coherence tomography device, wherein the polarimetric optical coherence tomography device comprises a time domain polarimetric optical coherence tomography device configured to analyze with depth resolution of about one micron or finer the residual stress depth profile of the cover glass; and
a chemical processing bath having parameters that are adjustable based upon depth resolved analysis of the residual stress depth profile of the cover glass.
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Abstract
Apparatus, systems and methods for improving strength of thin cover glass for electronic devices are disclosed. Optical coherence tomography analysis may reveal fine details of a residual stress profile within chemically strengthened cover glass. One or more parameters of chemical strengthening treatments may be adjusted, based upon the analysis of the residual stress profile.
152 Citations
23 Claims
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1. An apparatus comprising:
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a polarimetric optical coherence tomography device configured to use ultrashort polarized probe pulses to analyze with depth resolution of about one micron or finer a cover glass having a residual stress depth profile; a fixture configured to align the cover glass in an optical coupling with the ultrashort polarized probe pulses of the polarimetric optical coherence tomography device, wherein the polarimetric optical coherence tomography device comprises a time domain polarimetric optical coherence tomography device configured to analyze with depth resolution of about one micron or finer the residual stress depth profile of the cover glass; and a chemical processing bath having parameters that are adjustable based upon depth resolved analysis of the residual stress depth profile of the cover glass. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for depth resolved stress profile analysis comprising:
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optically coupling a time domain optical coherence tomography device to a cover glass having a stress depth profile within the cover glass; and determining depth resolved analysis of the stress depth profile of the cover glass. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A non-transitory computer readable medium including at least computer program code stored thereon for depth resolved stress profile analysis of a cover glass having a stress depth profile within the cover glass, said computer readable medium comprising:
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computer program code for receiving depth resolved polarization dependent time domain interferogram data from detectors optically coupled to the cover glass; and computer program code for determining a depth resolved analysis of the stress depth profile of the cover glass. - View Dependent Claims (21)
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22. A method for controlling parameters of chemical processing for strengthening cover glass using depth resolved stress profile analysis comprising:
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strengthening cover glass using a chemical strengthening process according to a first set of parameters, so as to introduce a stress profile within the cover glass; pulse illuminating the cover glass to generate signal pulses from the cover glass; determining from the signal pulses a depth resolved analysis of the stress profile of the cover glass; and adjusting at least one member of the set parameters of the chemical strengthening process based upon the depth resolved analysis of the stress profile of the cover glass.
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23. An apparatus for depth resolved stress profile analysis comprising:
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A source of ultrashort illumination pulses; a splitter for splitting the ultrashort illumination pulses into probe pulses and reference pulses; a cover glass having a stress depth profile within the cover glass, wherein the cover glass is optically coupled to the splitter for receiving the probe pulses and for generating signal pulses in response to the probe pulses; a polarization splitter configured to split the reference pulses and the signal pulses depending upon polarization thereof; and a time domain analyzer configured to determine a depth resolved analysis of the stress depth profile of the cover glass based upon the reference pulses and signal pulses.
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Specification