摘要:

Atmospheric compensation has been demonstrated using a liquid crystal light valve as a monolithic, integrated, wavefront sensor-corrector in a closed loop, all-optical configuration. For successful demonstration of this device, liquid crystal candidates were surveyed for high birefringence and fast time response in the blue region. BDH-E44 was selected with the highest figure of merit and a birefringence of 0.342 at 410 nm. Accelerated photostability studies indicated that the exclusion of oxygen/moisture extended the LC lifetime by twofold, while photo-exposure and applied electrical signal limited the lifetime due to photoinduced electrochemical degradation. A sealed BDH-E44 test cell after 60 Wh/cm2of 405 × 20 nm light and electrical exposure exhibited 3% decrease in the effective δn and a 12% shift in the operating voltage. However, the LC recovered from the sealed test cell after photo exposure showed no significant change in composition.

ISSN:1058-725X    

DOI:10.1080/10587259508033615

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A method for studying adsorption and desorption processes of impurity ions in nematic liquid crystal cells is proposed. The experimental results for 4-cyano-4‘-pentyl biphenyl are interpreted in terms of a rate-equation approach and the time constants for the adsorption and desorption processes of the ions are determined.

ISSN:1058-725X    

DOI:10.1080/10587259508033616

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper describes the fabrication and performance of a novel device based on liquid crystals dispersed in a polymer matrix. A low molecular weight liquid crystal material is introduced into a pre-formed, thin, porous, low density polymer film. Application of an electric field across the thin film produces a change in the transmission of the film just as in conventional Polymer Dispersed Liquid Crystals (PDLC) due to the reorientation of the liquid crystal director. Thus the device acts as a shutter. One significant advantage of this type of device over conventional PDLC is that there is no intermixing of the liquid crystal and monomeric material. Also compressible porous polymer matrices can be formed1giving the potential for controllably distorting the pores in a given direction. The formation and switching characteristics of a device using a porous polymer based on styrene and divinylbenzene is described.

ISSN:1058-725X    

DOI:10.1080/10587259508033617

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Long-term perfect bistable switching of 1,5μm thick Ferroelectric Liquid Crystal (FLC) cell oriented by photoanisotropic (PA) films was demonstrated even in2case of a large spontaneous polarization Ps=100nC/cm. The condition of a good SmC* orientation quality was shown to be the existence of a nematic phase N*. The bistability properties of PA-films aligned FLC cell, kept for a while in a short-curcuiting state, are easily restored, which is not observed in FLC cells oriented by usual rubbing technique.

ISSN:1058-725X    

DOI:10.1080/10587259508033618

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The DLFLC, which shows various characteristics as a domain-less switching and fast response time when low voltage is applied is produced by us.

ISSN:1058-725X    

DOI:10.1080/10587259508033619

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In this paper, based on experimental results, a model of the director coniiguration of amorphous nematic liquid crystal disphys(a-n-LCDs) was related. From our study we find that the a-n-LCDs are characterized with disordered surface alignment. Based on the modeling, a detailed analysis of the influence of parameters on display properties is given out, and the discussion shows that d/p=1/4 is not a strict condition for display use of a-n-LCDs, even though d/p > 112, good E-O property for display use can also be obtained. The a-n-LCDs supply a way to avoid the rubbing treatment and exhbit display properties of good color reproduction and wide viewing angle. When the value of d/p is increased, the threshold E-O curves become steep, and this supplies the novel n-LCDs with a high-multiplexing capacity.

ISSN:1058-725X    

DOI:10.1080/10587259508033620

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The highly efficient IR-modulation has been achieved using LC electro-optic elements. Experimental infrared modulator elements have been fabricated and demonstrated utilizing the transient light scattering effect of ferroelectric liquid crystal with asymmetric waveform voltage drive. The new elements performed 80%, 50%, 40% and 25% modulation degree in the 632.8nm, 2, 3-5 and 8-12 μm region. And we observed micro domain structure under the scattering state by a polarizing microscope to understand the mechanism of the domain switching. In addition, we evaluated properties of the scattering angular and temperature dependence quite important for the design of optics for the application in the infrared range.

ISSN:1058-725X    

DOI:10.1080/10587259508033621

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Multicomponent mixtures composed of two group of polar nematics: one taken from tri-ring or four-ring compounds with the cyano terminal group and the second taken from biring cyano compounds were studied. In these systems the induced smectic Adphase in the form of a nematic ‘island’ surrounded by a nematic ‘see’ occurs and after introducing a chiral component a TGBAphase is created and a selective reflection of light with a reverse colour sequence upon temperature (from blue to red) is observed. The shape of the induced Adphase and the concentration of the chiral components influences the properties of the selective reflection. The mixtures with the selective reflection of light were dispersed in a polymer and the obtained foils were tested as sensors of pressure.

ISSN:1058-725X    

DOI:10.1080/10587259508033622

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The paper presents the results of the investigation of the thermal stability of compounds being the components of liquid crystal mixtures. For the evaluation of the thermal stability of liquid crystals a modified method was used which consists in exposing the sample to the elevated temperature (150°C) and measuring its resistivity at the same time. It was stated that the thermal stability of a compound is mainly affected by the character of bonds in the molecule and especially by the type of an end group. The most sensitive to the temperature are compounds containing the -NCS group but this cannot be an unconditional proof for the compounds to be chemically unstable at room temperature

ISSN:1058-725X    

DOI:10.1080/10587259508033623

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

ISSN:1058-725X    

DOI:10.1080/10587259508033564

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor