摘要:

The thin layers of homogeneously oriented NLC applied on the surface under investigation as a free film can be used as unusual recording media that permits to visualize the two-dimensional distribution of surface tension with high optical resolution and sensitivity. The changes of surface tension may detect different local defects without applying external electrical fields. On this basis a new non-destructive method to study the quality of different material surfaces has been developed. Here we discuss the new application of NLC technique for histological identification of malignancies.

ISSN:1058-725X    

DOI:10.1080/10587250008023246

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Large numerical aperture telescope with nonlinear optical correction for distortions, designed for the remote self-luminous object imaging, was realised in experiment and investigated. Dynamic hologram, recorded in optically addressed liquid crystal spatial light modulator, was used as the corrector. Nearly diffraction limited performance of the system was demonstrated.

ISSN:1058-725X    

DOI:10.1080/10587250008023247

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Modeling Universal System of Liquid Crystal Displays (MOUSE—LCD) software is demonstrated for the calculation of LC electrooptical behavior and optimization of the new LCD prototypes. In our paper we will demonstrate the effectiveness of the software on various important examples enlisted below.

ISSN:1058-725X    

DOI:10.1080/10587250008023248

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

It has been considered that applying symmetric addressing schemes can avoid the ionic effect in FLCDs. In this paper, image sticking measurements have been performed to investigate the ion transport process on applying symmetric addressing signals and hence its influence. It has been found that by reversing the polarity of the addressing voltage each frame, image sticking effect has been prominently reduced, nevertheless not completely to zero. Further study has revealed the fact that although accumulation of ions is avoided to a large extent, a number of ions are still trapped at the interface of alignment layer and the liquid crystal layer. These trapped ions cannot be easily released by simply reversing the polarity of the addressing signal and thus influence the electric field distribution in FLC. The number of trapped ions depends on the property of the interface.

ISSN:1058-725X    

DOI:10.1080/10587250008023249

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A laser video projection method that is based on the image mode laser has been developed. The image mode laser is a laser with a spatial light modulator placed inside an optically pumped high-gain laser cavity to provide area-selectiveQ-modulation. The transverse mode of this laser creates a desired image that can be projected onto a viewing screen. This method of creating a lasing projected image has the potential advantages of higher contrast and brightness at the faceplate over the traditional method of spatial light modulation of a uniform optical source. The elimination of scanning systems results in a simpler design without mechanical parts; also, this system can potentially be adapted to full color with a single laser providing optical pumping for image mode lasers of all three primary colors.

ISSN:1058-725X    

DOI:10.1080/10587250008023250

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Polarization features of polymer dispersed liquid crystal (PDLC) films were investigated experimentally. An alignment of PDLC films was achieved by a shear deformation of the films at an accurate control of geometric parameters. A numerical interpretation of experimental results was made for practical application An influence of droplets shape to the polarization features of the PDLC film was estimated.

ISSN:1058-725X    

DOI:10.1080/10587250008023251

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Using MOUSE-LCD software we analyze, how the parameters of the “guest-host” cell effects such basic characteristics of LCDs as the contrast, brightness and magnitude of the viewing angles. The basic construction of “guest-host” LCD includes one input polarizer and reveals a negative contrast. We showed, that to increase the average contrast, transmission and viewing angles of “guest-host” LCDs we have to use the LC cells with the twist angle of 90°, while the thickness of the LC layer should be sufficiently high. The concentration of the dye must be optimized for the applied values of LC cell thickness and twist angle. The higher values of LC optical anisotropy Δn results in the increase of the display contrast in our case, contrary to the non-polaroid variant of “guest-host” LCDs.

ISSN:1058-725X    

DOI:10.1080/10587250008023252

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In this work we have studied, by light transmission, the effects of either UV or high temperature exposure on the electro-optical properties of cellulose derivatives based PDLC type cells prepared from hydroxypropylcellulose (HPC) and HPC cross-linked with 1,4 - diisocyanatobutane (BDI) (7,0% w/w). The time evolution of the electro-optical properties of different cells, some under UV exposure, and others under high temperature (65 °C), was recorded for times up to 7 days. Two sets of cells were analysed, one with electric field off during exposure, the other with electric field on. The results obtained show that no significant changes of the electro-optical properties of the cells occurred under the studied conditions, meaning that these systems are very stable and so good candidates for industrial applications.

ISSN:1058-725X    

DOI:10.1080/10587250008023253

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Chiral nematic liquid crystals which possess a large negative dielectric anisotropy (Δε < 0), exhibit a larger dielectric constant parallel to the helical axis than perpendicular to it. In a liquid crystal cell with homeotropic boundary conditions, the direction of the helical axis is parallel to the cell surfaces and the sample adopts a pseudo focal conic texture. On the application of a suitable AC field, the director is rotated, such that the helix direction is now perpendicular to the surface and the sample adopts a Grandjean texture. The wavelength of reflected light in this “field On” state is a function of temperature and the magnitude of the applied field. In this paper we show that highly twisted chiral nematic liquid crystals, which possess a large negative dielectric anisotropy are potentially useful as optical modulators and in electrically tuneable mirrors.

ISSN:1058-725X    

DOI:10.1080/10587250008023254

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Electrically Controlled Birefringence (ECB) cells are often used to fabricate switchable color filters. The color filter we consider consists of 3 polarizers and 2 birefringent modules. Each module consists of a combination of ECB cells and retardation foils. When a maximum response time is taken into account, one can determine a minimum voltage drop that has to be across the ECB cells. This results in a smaller interval in which the retardation of the cell can vary. Since different colors are achieved by varying the retardations of the two modules, it will be more difficult to obtain a saturated red, green and blue color. In this paper we describe a graphical method to design a fast switching color filter with saturated colors. The method can be used for different kinds of liquid crystal cells.

ISSN:1058-725X    

DOI:10.1080/10587250008023255

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor