New absorptive mode reflective liquid-crystal display device

White, Donald L.; Taylor, G.W.

doi:10.1063/1.1663124

Cited by 354 publications

(81 citation statements)

References 7 publications

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“…The effect observed, termed the guest-host effect, is 2 thought to be primarily due to the steric interactions between the dye and the LC, i.e. van der Waals interactions.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the alignment of the dipole moment of the dye with the director of the LC offers the prospect of a coloured liquid crystal display (LCD) that can be switched to a transparent state in an on-off fashion with an external electric field [1][2][3][4]. Additionally, it has been observed that the electro-optic response time of nematic LCs can be improved by dye dopants with large dipole moments, which is also of great interest in display applications [5].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Orientation and Solvatochromism of Dyes in Liquid Crystals

Pålsson¹,

Szablewski²,

Roberts³

et al. 2003

Molecular Crystals and Liquid Crystals

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Citation for published item: ¦ lssonD vF yF nd zlewskiD wrek nd oertsD eF nd wsutniD eF nd voveD qF hF nd grossD qF rF nd floorD hF nd uyD eF tF nd oolhouseD eF hF nd wsutniD eF nd sudD eF @PHHQA 9yrienttion nd solvtohromism of dyes in liquid rystlsF9D woleulr rystls nd liquid rystlsFD RHP @IAF ppF RQESQF Further information on publisher's website: httpXGGdxFdoiForgGIHFIHVHGURRVITTVS Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The orientation and solvatochromism of some dye molecules in a liquid crystal have been investigated. Interactions with the host and the structure of the dye molecule affect the macroscopic alignment of dichroic dye molecules in a liquid crystal. It was observed that some dye molecules show a large bathochromic shift of their absorption maxima in the liquid crystal host relative to the situation in isotropic solvents. It is suggested that this is due to the occurrence of a much weaker reaction field in the anisotropic, rigid host. These dye molecules show little or no apparent order in the anisotropic host despite the observation of a reduction in the electro optic switching time when the dye is present. The highest degree of macroscopic alignment was observed for a merocyanine compound, which showed the smallest solvatochromic shift in the liquid crystal host. These results are discussed in terms of the steric, dipolar and hydrogen bond interactions between the guest and the host.

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“…The effect observed, termed the guest-host effect, is 2 thought to be primarily due to the steric interactions between the dye and the LC, i.e. van der Waals interactions.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Orientation and Solvatochromism of Dyes in Liquid Crystals

Pålsson¹,

Szablewski²,

Roberts³

et al. 2003

Molecular Crystals and Liquid Crystals

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“…However, the short-wavelength bands were calculated to arise from a number of different transitions, in some cases with different values of β, as listed in Table 3. The calculated dichroic ratios of these bands were determined by summing the absorbance contributions from the total number of transitions, m, contributing to each band, according to Equation (5), which is derived from Equations (2) and (3), and where S ϕ i is the calculated order parameter of each transition determined using Equation (4). This approach assumes that the absorption coefficient of each transition, i, is proportional to the calculated oscillator strength, f i , and that all the transitions provide a wavelength-independent contribution to the band.…”

Section: Calculated Dichroic Order Parametersmentioning

confidence: 99%

“…In general, display technology has been the most widely proposed application for these systems because the incorporation of a suitable dye or mixture of dyes within a host in a liquid crystal cell provides a device that may be switched from a transmitting state to an absorbing state. Many variations on this basic concept have been proposed, for example, dual-layer devices [2] or devices incorporating quarter-wave plates [3] that do not require polarisers, phase-change devices that utilise cholesteric host molecules [4] and scattering devices utilising smectic A hosts [5]. Such guest-host systems have also been proposed for other wide-ranging applications, such as smart windows [6], solar cell precursors [7], security devices [8], diffraction gratings [9] and polarisers [10].…”

Section: Introductionmentioning

confidence: 99%

Guest–host systems containing anthraquinone dyes with multiple visible transitions giving positive and negative dichroic order parameters: an assessment of principal molecular axes and computational methods

et al. 2017

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(2017) Guest-host systems containing anthraquinone dyes with multiple visible transitions giving positive and negative dichroic order parameters: an assessment of principal molecular axes and computational methods. Liquid Crystals, Northumbria University has developed Northumbria Research Link (NRL) to enable users to access the University's research output. Copyright © and moral rights for items on NRL are retained by the individual author(s) and/or other copyright owners. Single copies of full items can be reproduced, displayed or performed, and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided the authors, title and full bibliographic details are given, as well as a hyperlink and/or URL to the original metadata page. The content must not be changed in any way. Full items must not be sold commercially in any format or medium without formal permission of the copyright holder. The full policy is available online: http://nrl.northumbria.ac.uk/policies.html This document may differ from the final, published version of the research and has been made available online in accordance with publisher policies. To read and/or cite from the published version of the research, please visit the publisher's website (a subscription may be required.)Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=tlct20 Three 1,4-disubstituted anthraquinone dyes with bis(4-n-butylphenyl) substituents connected via amine or amide linking groups have been studied as guest molecules dissolved in the nematic host E7. UV-visible absorption spectroscopy has shown each of the dyes to exhibit multiple absorption bands in the visible region, and dichroic order parameters obtained from polarised spectra of aligned guest-host samples were shown to differ significantly between the bands for each dye, and between the dyes. Time-dependent density functional theory calculations indicated that each dye exhibits several transitions, giving transition dipole moment vectors with a range of orientations, and fully atomistic molecular dynamics simulations of the guest-host mixtures showed differences in the calculated molecular alignments of the dyes. Combining the results from these two sets of calculations enabled a comparison of molecular alignment models based on the moments of inertia and the surface tensors of the dyes. The match between calculated and experimental values was improved significantly when using the surface tensor rather than the moment of inertia model, indicating that the shapes of the molecular surfaces of these dyes are crucial to their alignment. A novel method of calculating polarised UV-visible absorption spectra of dyes in liquid crystal hosts is also presented.

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“…Since a contact lens is, however, often not thicker than 120 μm, a polarizer free approach is needed as no sufficiently thin polarizers are commercially available at present. Therefore, a transmissive guest-host configuration as proposed by White and Taylor [3] was chosen with a homeotropic alignment and a twist angle of 180°. A conceptual drawing of how such a liquid crystal (LC) based contact lens display may look like is presented in Figure 1.…”

Section: Background and Objectivesmentioning

confidence: 99%