US 2006/0215159 A1 · Method and apparatus for determining liquid crystal cell parameters from full Mueller matrix measurements

Abstract

Method and apparatus for testing of LCD panels is disclosed. An LCD panel under test is mounted to a translatable table between a polarization state generator and polarization state analyzer. For each location on the screen to be tested, a continuum of known polarization states are launched through the LCD screen and detected by the polarization state analyzer. Electrical signals representative of such polarization states are acquired by a computer. Within the computer, a model of polarization properties of the LCD panel is developed based on estimations of what the physical parameters of the LCD panel are believed to be. RMS differences between simulated polarization properties and measured polarization properties are minimized by iteratively refining the modeled physical cell properties, at which point cell thickness and other physical parameters of the LCD screen may be deduced.

Claims29

Dependent claims

A method for determining at least one physical parameter of a liquid crystal cell under test comprising:

A) launching a beam of light having a plurality of polarization states through said liquid crystal cell under test, each polarization state of said plurality of polarization states having different orientation, ellipticity and handedness from other said polarization states of said plurality of polarization states,
B) measuring selected points along said plurality of polarization states after passing through said liquid crystal cell under test,
C) in a computer processing device, developing a liquid crystal cell model including modeled polarization properties based on at least one estimated physical parameter of said liquid crystal cell under test,
D) adjusting said computer model until a close match is obtained between said modeled polarization properties and measured polarization properties of said liquid crystal cell under test,
E) whereby when said close match is obtained, said at least one estimated physical parameter of said liquid crystal cell model is indicative of a corresponding said physical parameter of said liquid crystal cell under test.

2 more elements

A method for determining physical parameters of a liquid crystal cell comprising:

A) measuring polarization properties of said liquid crystal cell under test,
B) In a computer processing device, developing a mathematical model of a liquid crystal cell, said mathematical model using estimated physical parameters to model said liquid crystal cell under test,
C) adjusting values in said mathematical model of said liquid crystal cell until a close match is obtained between polarization properties of said mathematical model of a liquid crystal cell and measured said polarization properties of said liquid crystal cell under test,
D) providing an indication of quality of said liquid crystal cell under test based on said estimated physical parameters of a closely matched said mathematical model of a liquid crystal cell to said liquid crystal cell under test.

1 more element

A method for determining at least one physical parameter of a liquid crystal cell to determine whether said liquid crystal cell under test is defective comprising:

A) directing sequences of polarization states generated by a polarization state generator at said liquid crystal cell under test, each polarization state of said sequences of polarization states differing from other polarization states of said sequences of polarization states in orientation. ellipticity and handedness,
B) analyzing said sequences of polarization states as modified by said liquid crystal cell under test by a polarization state analyzer,
C) calculating polarization properties of said liquid crystal cell under test,
D) in a computer model including at least one estimated physical parameter of said liquid crystal cell under test, adjusting said at least one estimated physical parameter until a close match is obtained between analyzed said polarization properties of said liquid crystal cell under test and calculated said polarization properties of said computer model of a liquid crystal cell,
E) providing at least one indication of a closely matched said estimated physical parameter representative of a corresponding physical parameter of said liquid crystal cell under test.

2 more elements

Dependencies are inferred from the claim text.

Method and apparatus for determining liquid crystal cell parameters from full Mueller matrix measurements

Life of this patent

Method and apparatus for determining liquid crystal cell parameters from full Mueller matrix measurements

Life of this patent

Abstract

Claims29