摘要:

Novel LCD, which transmits circularly polarized light, is reported. The circular polarized light enables us to see the LCD screen through polarized sunglasses. It is developed for outdoor application, such as mobile computing, car navigator, and so on. The circular light is achieved by placing additional quarter wave film upon the screen.

ISSN:1058-725X    

DOI:10.1080/10587259808025102

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We have developed an economic liquid crystal-polymer dispersion material that can be used for storing optical holographic images, The obtained results show that the written grating-holograms are permanent, but are electrically switchable. Further, we studied the dynamical behavior and the temperature-dependence of the formed gratings. The gratings morphologies were also investigated using scanning electron microscopy (SEM). The results showed the thermal grating was competing with the grating due to photopolymerization. The former dominated in the initial period, Later, it was offset or quenched by the photopolymerization effect which eventually dominated and determined the characteristics of the final gratings whose diffraction efficiencies were found to have a good correlation with their SEM images.

ISSN:1058-725X    

DOI:10.1080/10587259808025103

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Infra-red spectroscopy has been used to follow the evolution of the photopolymerization of mesogenic diacrylates in a liquid crystal matrix. The kinetic is a first order one as in isotropic solvents. The rate constant and the final conversion ratio depend on the monomer concentration. The order parameter of the liquid crystal decreases during polymerization due to reorganization. The electro-optical characteristics of a gel depend on the nature of the monomer and on the density of cross-linked bonds. A reversible electro-optical behaviour is observed with a high density of cross-linked bonds. Gels with low densities of cross-linked bonds exhibit a memory effect.

ISSN:1058-725X    

DOI:10.1080/10587259808025104

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The effects of polymer networks with electric field application to the electro-optic characteristics of ferroelectric liquid crystal devices have been studied. The polymer networks formed in SmC* phase are anisotropic and fibrils-like. Scanning electron microscopy (SEM) and optical microscopy were used to study the polymer networks and the stabilized panels. The electro-optic characteristics of cells were also measured. The experimental results show that presence of anisotropic polymer networks have great effects on the FLC molecules orientation and electro-optic characteristics. The E-O curve of the device is like “V” shape when the monomer concentration is 4%, so it is easier to get gray scales than SSFLC in devices.

ISSN:1058-725X    

DOI:10.1080/10587259808025105

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In nematic liquid crystals light is strongly scattered from director fluctuations. We are interested in the limit where the incoming light wave is scattered many times. Then, the light transport can be described by a diffusion equation for the energy density of light with diffusion constants D∥and D⊥, respectively, parallel and perpendicular to the director. We start from a radiative transfer theory, connect the diffusion constants to the dynamic structure factor of director fluctuations, and shortly discuss our results. Temporal correlations of the diffusing light probe the dynamics of director modes on much shorter time scales than single light scattering experiments. To account for the decaying temporal correlations, one has to add an absorption term to the diffusion equation, which we also link to the dynamic structure factor.

ISSN:1058-725X    

DOI:10.1080/10587259808025106

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We present a detailed discussion of the fundamental mechanisms for recently observed nonlinear electro-optical wave mixing effects in nematic liquid crystal films. Experimental results on photoconductivity, photorefractive-like two beam coupling, beam amplification, self-diffraction, and storage holographic grating formation in dye- and Fullerene C60and C61doped nematic films are presented along with a review of two- and four- wave mixing theories. Nematic liquid crystal films are shown to be potentially useful for adaptive and optical storage applications.

ISSN:1058-725X    

DOI:10.1080/10587259808025107

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The prism coupler method has been applied to the investigation of refractive index profile (RIP) in liquid crystal (LC) layer. Waveguide modes have been excited in thin LC layer arranged as a planar wavequide. Modal lines of the modes excited in the waveguide are observed as evanescent in dielectric prism by tunnelling effect. Measured position of each modal line provides a mode propagation constant value. In a multimodal waveguide the set of the propagation constants creates data for RIP determination by means of M-line procedure. The usefulness of the M - line method to the investigations of LC waveguides is illustrated and verified by nematic liquid crystal (NLC) elastic response measurements.

ISSN:1058-725X    

DOI:10.1080/10587259808025108

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Switchable diffraction gratings consisting of a dual-frequency-addressable nematic liquid crystal embedded in a polymer matrix were prepared using a holographic technique. The photopolymerization of a polymer-precursor, initiated by an optical intensity grating leads to the grating formation within a few seconds. The diffraction efficiency of the resulting grating structure can be modulated by an external electric field due to a variation of the frequency at constant voltage. The corresponding response time is a few ms, i. e. much faster than the relaxation time of the liquid crystal at zero field. The dispersion of white light and the surface modulation of a PDLC sample with one free surface are demonstrated as possible applications for PDLC gratings.

ISSN:1058-725X    

DOI:10.1080/10587259808025109

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:1058-725X    

DOI:10.1080/10587259808025071

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor