Method for detecting and indicating wedge in glass

Claim 1

A method of measuring wedge in a glass sheet which comprises: generating a beam of parallel light rays; projecting said beam through said glass sheet; reflecting said projected beam back through said glass sheet; passing said reflected beam through a pair of adjustable correction devices, each of said devices controlling the direction of further projection of said reflected beam along selected axes depending on the reflected beam along selected axes depending on the relative positions of said devices; separating said projected beam into at least four subbeams, two of said subbeams being representative of the light intensity along one axis of said reflected beam and two of said subbeams being representative of the light intensity along a second axis of said reflected beam, said first and said second axes being respectively aligned with the selected axes along which said adjustable control devices control the projection of said reflected beam; projecting said first two subbeams onto separate light measuring devices which produce a signal corresponding to the intensity of the beam projected thereon; moving said adjustable correction device controlling the projection of light along said first axis to a position which causes a prescribed relationship to be established in the signals developed by said light-measuring devices measuring said first two subbeams; projecting said second two subbeams onto separate light measuring devices which produce a signal corresponding to the intensity of the beam projected thereon; and repositioning said adjustable correction device controlling the projection of light along said second axis to a position which causes a prescribed relationship to be established in the signals developed by said light-measuring devices measuring said second two subbeams, whereby the position of said adjustable correction devices indicate the direction and degree of wedge in said glass sheet along said two axes.

Claim 2

A method of measuring wedge in a glass sheet which comprises: generating a beam of parallel light rays; projecting said beam through said glass sheet; reflecting said projected beam back through said glass sheet; passing said reflected beam through a pair of adjustable correction devices, each of said devices controlling the direction of further projection of said reflected beam along selected axes depending on the reflected beam along selected axes depending on the relative positions of said devices; separating said projected beam into at least four subbeams, two of said subbeams being representative of the light intensity along one axis of said reflected beam and two of said subbeams being representative of the light intensity along a second axis of said reflected beam, said first and said second axes being respectively aligned with the selected axes along which said adjustable control devices control the projection of said reflected beam; projecting said first two subbeams onto separate light measuring devices which produce a signal corresponding to the intensity of the beam projected thereon; moving said adjustable correction device controlling the projection of light along said first axis to a position which causes a prescribed relationship to be established in the signals developed by said light-measuring devices measuring said first two subbeams; projecting said second two subbeams onto separate light measuring devices which produce a signal corresponding to the intensity of the beam projected thereon; and repositioning said adjustable correction device controlling the projection of light along said second axis to a position which causes a prescribed relationship to be established in the signals developed by said light-measuring devices measuring said second two subbeams, whereby the position of said adjustable correction devices indicate the direction and degree of wedge in said glass sheet along said two axes.