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Achromatic Liquid Crystal Electro-Optical Devices Based on a Twisted Vertical Alignment Configuration
Başlık:
Achromatic Liquid Crystal Electro-Optical Devices Based on a Twisted Vertical Alignment Configuration
Yazar:
Chang, Kai-Han, author.
ISBN:
9780438093058
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (194 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-10(E), Section: B.
Committee members: Philip Bos; Liang-Chy Chien; Antal Jakli; Elizabeth Mann; Michael Tubergen.
Özet:
Liquid crystal (LC) possesses the unique combination of optical and dielectric anisotropy, which makes it the choice of material for electro-optical (EO) device development. With different orientations defined by surface treatment and/or dopant in bulk, the resulting EO response provides abundant opportunities for innovative device development. In general, EO responses of liquid crystals are wavelength-dependent, making them challenging for displaying vivid color images without additional electronic or physical enhancement.
In this dissertation, to mitigate the issue of wavelength-dependent of EO issue, achromatic liquid crystal EO devices are designed and demonstrated with a twisted-vertical alignment (TVA) configuration. While the original TVA mode was reported in 1993, the bottleneck of long response time resulting from degeneracy of tilt angle and defect annihilation during switch-on process stopped the new liquid crystal mode from becoming applicable to emerging devices. A polymer stabilization approach is proposed and experimentally demonstrated to command the homeotropic-to-twist transition for fast response time. Under optimum polymerization conditions, an 83% improvement in response time is achieved while attaining a high contrast ratio of 1300:1. The aligning effect contributed by the polymer structure is validated through theoretical analysis and simulation, which is based on free-energy calculation in the liquid crystal and polymer composite system.
The second part of dissertation is in search of applications beyond displays. With the advantage of suppressed wavelength dispersion, both liquid crystal lens and microlens array with TVA configuration are demonstrated to have electrically-tunable focal length and reduced chromatic aberration. Both liquid crystal lenses show the merits of low-operation voltages of tunable focal length and both positive and negative lens power. We envision that this work will open new pathways to explore innovative optical and photonic devices.
Notlar:
School code: 0101
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(687072.1) | 687072-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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