Optics: measuring and testing – For light transmission or absorption – By comparison
Reexamination Certificate
2007-11-20
2010-12-21
Nguyen, Sang (Department: 2886)
Optics: measuring and testing
For light transmission or absorption
By comparison
C349S118000
Reexamination Certificate
active
07855787
ABSTRACT:
To determine the tilt angle in a twisted nematic liquid-crystal cell, the transmission of the cell is calculated as a function of the angle of incidence of a light beam of given wavelength λ using apparent values of the thickness of the cell cavity, of the extraordinary index and of the twist angle, in order to obtain a plurality of simulation curves, one per given pretilt angle, the transmission curve is measured as a function of the angle of incidence of the cell along the axis passing through the top and bottom positions of the cell, for the light beam of wavelength λ, using a contrast meter, and the coincidence between this measurement curve and a curve from among the plurality of simulation curves gives the pretilt angle of this cell.
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Nguyen Sang
Oblon, Spivak McClelland, Maier & Neustadt, L.L.P.
Thales
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