Ion Transport and Switching Currents in Smectic Liquid Crystal Devices

Neyts, Kristiaan; Beunis, Filip

doi:10.1080/00150190600968405

Cited by 12 publications

(9 citation statements)

References 14 publications

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“…9,10 The transport of ions in ferroelectric smectic liquid crystals was studied from the point of view of their potential application in display technology with the emphasis on switching and bistability of smectic displays. 11 Here, we provide a proof-of-concept demonstration that it is possible to visualize the presence and the motion of ions in LC materials with the use of optical microscopy. We use thin films spanning a round opening with the tip of a needle positioned in the center of the round rim, either slightly above the plane of the rim, or slightly below it.…”

Section: Introductionmentioning

confidence: 99%

Dynamic charge separation in a liquid crystalline meniscus

et al. 2009

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Section: Introductionmentioning

confidence: 99%

Dynamic charge separation in a liquid crystalline meniscus

et al. 2009

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“…A remaining challenge for bistable FLC cells is that the range of drive conditions and temperature over which good alignment is maintained [26,27] must be expanded in order to be ready for commercial use. Also, this investigation has focused on the static or quasistatic bistable switching characteristics of FLC cells; a more complete understanding may require the inclusion of dynamics such as the formation and propagation of up and down domain walls [28], viscosities and flow [24,29,30], and ionic conductivity of the FLC layer due to impurities [22,23,[31][32][33][34]. In addition, because its effects grow as E 2 , dielectric anisotropy [omitted in Eq.…”

Section: Summary and Discussionmentioning

confidence: 99%

Polarization-stiffened ferroelectric liquid crystals: A thickness-independent bistable switching voltage with a lower limit of about 2 V and the transition to thresholdless switching

O’Callaghan¹

2015

Phys. Rev. E

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Typical ferroelectric Sm-C(*) liquid crystal (FLC) cells exhibit a voltage threshold for switching from one stable state to another despite the FLC's response being inherently continuous and thresholdless (free rotation of the director around the tilt cone). This switching threshold is due to FLC-surface interactions and to the chevron smectic structure commonly formed in cells. It is shown here that the FLC electrostatic energy contribution ∼P(S)(2) responsible for thresholdless switching of high-P(S) FLCs also plays a key role in the bistable switching of lower-P(S) FLCs. Among the consequences are that it can be difficult to lower a cell's threshold below V(TB)∼3.4(B/ɛ(F))(1/2) (B and ɛ(F) are the FLC's elastic and dielectric constants), that a cell's threshold becomes independent of cell thickness once it substantially exceeds the characteristic length ξ(P)=(ɛ(F)B)(1/2)/P(S), and that there are conditions under which alignment layer capacitance can decrease rather than increase the threshold (i.e., transition to thresholdless switching). A model that predicts and explains these behaviors is presented along with threshold measurements of representative FLC cells.

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“…Dissolved charged impurities move from one electrode to the other and may also participate in electrode reactions. The most important cause of FLC modulator performance degradation is the buildup of electric fields from ions within the FLC substance layer [6,7]. All liquid crystal devices contain some concentration of ionic species.…”

Section: The Problemmentioning

confidence: 99%

P‐11.4: Concept of Electronic Controlling the Ferroelectric Liquid Crystal Shutter at Unequal Durations of its Open and Closed States

Ежов

Kompanets

2019

Symp Digest of Tech Papers

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Fast transient times of ferroelectric liquid crystal (FLC) modulators (shutters) provide accurate selection of pulse light fluxes, for example, the active selection of view images in the stereoscopic applications. The problem of the electronic control of the FLC shutter appears in the case of unequal durations of its alternating open and closed optical states. Corresponding unequal portions of control electrical power during positive and negative polarities of the control voltage cause the degradation of the FLC performance. Main reason of the degradation is the inequality of the volume ion charges induced into the FLC layer by positive and negative control voltage. In this paper, the concept of solution to this problem is suggested with the corresponding experimental verification. Our method allows to equalize the positive and negative control electrical power values without affecting the optical response of the FLC shutter by introducing the short time gaps into a longer control voltage waveform to lower the corresponding integral electrical power value.

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Ion Transport and Switching Currents in Smectic Liquid Crystal Devices

Cited by 12 publications

References 14 publications

Dynamic charge separation in a liquid crystalline meniscus

Dynamic charge separation in a liquid crystalline meniscus

Polarization-stiffened ferroelectric liquid crystals: A thickness-independent bistable switching voltage with a lower limit of about 2 V and the transition to thresholdless switching

P‐11.4: Concept of Electronic Controlling the Ferroelectric Liquid Crystal Shutter at Unequal Durations of its Open and Closed States

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