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Mechanism of image sticking after long‐term AC field driving of IPS mode
Author(s) -
Momoi Yuichi,
Tamai Kazuhiko,
Furuta Kaoru,
Lee TaeRim,
Kim KyeongJin,
Oh ChangHo,
Koda Tomonori
Publication year - 2010
Publication title -
journal of the society for information display
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.578
H-Index - 52
eISSN - 1938-3657
pISSN - 1071-0922
DOI - 10.1889/jsid18.2.134
Subject(s) - rubbing , materials science , liquid crystal display , mode (computer interface) , rheology , optics , liquid crystal , electric field , computer science , optoelectronics , physics , composite material , quantum mechanics , operating system
— An AC electric field to drive the IPS mode of a liquid‐crystal display (LCD) causes a reduction in the contrast after a long period of display operation. This phenomenon is refered to as the AC image‐sticking problem caused by long‐term driving. Thus far, there is no useful method of quantitatively evaluating AC image sticking. LCD panel products that use the IPS mode have been evaluated for a decade. In this paper, a new evaluation parameter (Δθ), which was recently proposed by Suzuki et al. , is introduced. It was calculated from the slight difference in the deviation angle of LC molecules from the rubbing direction. Results from several conditions of test samples are presented in this paper as a phenomena that reflect the interaction between the surface of the PI alignment and the LC molecules. The results and discussions describe reasons for azimuthal gliding after long display operation for weak AC voltage driving. It is explained by suitably adopting the Kelvin‐Voigt model which is used to discuss the rheology of viscoelastic material. It is concluded that the surface rheology of PI alignment is one of the most important factors for the contrast reduction of the AC image‐sticking problem.