Method of measuring optical characteristics of liquid crystal cells, measurement equipment therefor and method for manufacturing liquid crystal devices
US5532823A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 1994 |
| Grant date | Jul 2, 1996 |
| Priority date | — |
| Expiry date | Dec 22, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/1309
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
There is disclosed a method for measuring retardation .DELTA.nd of a liquid crystal cell in which a linearly polarized light beam is impinged upon a liquid crystal cell, the liquid crystal cell is rotated in a plane perpendicular to an optical axis of a measuring optical system so that the transmission through the liquid crystal cell for the light beam having a polarization parallel to that of the incident light beam becomes maximal, the wavelength of the incident light beam is varied to detect at least one wavelength .lambda..sub.s at which the transmission has an extreme and, finally, .DELTA.nd is calculated from .DELTA.nd=.lambda..sub.s .sqroot.m.sup.2 -(1/4) for the case of m-th minimal transmission or from .DELTA.nd=.lambda..sub.s .sqroot.m.sup.2 +m for the case of m-th maximal transmission.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.