LC Technology

Molecular Architectures in Thin Plastic Films by In-Situ Photopolymerization of Reactive Liquid Crystals

Multicolor Reflective Cholesteric Displays

Surface-Modified Reflective Cholesteric Displays

Holographic Reflective Liquid-Crystal Display

Optimization of Holographic PDLC for Reflective Color Display Applications

The Role of Surface Azimuthal Anchoring in the Electro-Optic Response of PDLC Films

Brightness Enhancement of Reflective Polymer-Dispersed LCDs

Large-Size Reflective Mosaic Displays Made of Self-Contained ECD Dots: Driving with Reduced Current Demands

A Color STN-LCD for Video Display Using Amplitude-Modulation MLS Technology

Investigation of the Active Drive Method for STN-LCDs

Dynamic Drive for Bistable Reflective Cholesteric Displays: A Rapid Addressing Scheme

Switching Mechanism of Bistable Reflective Cholesteric Displays

Novel LCD Color Projectors Based on Cholesteric Filters

An Optically Active Diffractive Device for a High-Efficiency Light Valve

Delayed Appearance of STN-LCD Cosmetic Defects Due to Conductive Contaminants

Overview of the Conduction Regimes in LCDs

STN Alignment on Rib-Spaced Plastic LCD Substrate

Polarizer-Free Reflective Amorphous Chiral Nematic Guest-Host LCDs

Polarized UV-Exposed Polyimide Films for Liquid-Crystal Alignment

A High-Information-Content Reflective Cholesteric Display

A Full-Color Video-Rate Anti-Ferroelectric LCD with Wide viewing Angle

Viewing-Angle-Enhancement System for LCDs

Properties of the OCB Mode for Active-Matrix LCDs with Wide Viewing Angle

Viewing Angle and Color-Uniformity Optimization of the Pi Cell

Four-Domain TN-LCD Fabricated by Reverse Rubbing or Double Evaporation

No-Rub Multi-Domain TFT-LCD Using Surrounding-Electrode Method

A Well-Controlled Tilted-Homeotropic Alignment Method and a Vertically Aligned Four-Domain LCD Fabricated by This Technique

TN-LCD with Quartered Subpixels Using Polarized UV-Light-Irradiated Polymer Orientation Films

Investigation of the Mechanism of the Surface-Induced Alignment of Liquid Crystals by Linearly Polymerized Photopolymers

Simulation of Display Characteristics of TN-LCD with Curvature Rubbing Pattern

Alignment of Ferroelectric Liquid-Crystal Molecules by Liquid-Crystalline Polymer

Computer Simulation of Director Profile in Three-Dimensional Electric Field

LCD Modeling as a Display Characterization Tool

A General Method to Solve the Deformation Profile of Chiral Nematic LCDs with Asymmetric Pretilt

Temperature-Independent Transmission of PDLC Films

Phase-Matched Biaxial Compensation Film for LCDs

Optics of Nematic Liquid-Crystal Cells in Circularly Polarized Light

A High-Contrast Wide-Viewing-Angle Low-Twisted-Nematic LCD Mode

The Performance of a Liquid-Crystal Polymer Film as an Optical Compensator for a Fast-Response STN-LCD

Display Characteristics of Amorphous ECB LCD: Polymer Stabilized Amorphous ECB Cell

Display Characteristics of Amorphous ECB LCD: Hybrid Aligned Nematic Cell

Axially Symmetric Aligned Microcell (ASM) Mode: Electro-Optical Characteristics of New Display Mode with Excellent Wide Viewing Angle

Polarizer-Free Reflective Spiral Polymer-Aligned Nematic GH-LCDs



Molecular Architectures in Thin Film Plastic Films by In-Situ Photopolymerization of Reactive Liquid Crystals
D. J. Broer
Philips Research Laboratories, Eindhoven, The Netherlands
full paper

Photo-initiated polymerization of reactive LCs produces films with permanent or recoverable monolithic molecular order. An overview of special techniques which create rather bizarre 3-D molecular architectures but which can be applied in a very controlled way to produce a variety of optical components is presented.

The process of in-situ photopolymerization of reactive mesogens leads to densely crosslinked liquid crystal (LC) networks. The molecular organization within the thin films can be accurately controlled by combining the various alignment techniques known for low mass LCs with structuring techniques known for photopolymerization. The films thus produced exhibit optical properties useful for polymerization control and/or color control in the various types of LCDs.

Multicolor Reflective Cholesteric Displays
L.-C. Chien, U. Müller, M.-F. Nabor, J. W. Doane
Liquid Crystal Institute and NSF ALCOM Center, Kent State University, Kent, OH
full paper

Multi-color reflective cholesteric displays (RCDs) are developed which show the three primary colors: red, green and blue. A tunable chiral material (TCM), whose chirality can be photochemically altered by exposing the cell to UV light, is the key factor in the production of a multi-color reflective cholesteric display. Pixelization of color pattern is achieved through photolithography.



Surface-Modified Reflective Cholesteric Displays
Z.-J. Lu, W. D. St. John, X.-Y. Huang, D.-K. Yang, J. W. Doane
Liquid Crystal Institute and Department of Physics, Kent State University, Kent, OH
full paper

The contrast and viewing angle of reflective cholesteric LCDs were optimized by suitably modified surfaces which which were characterized according to their roughness by AFM. Bistable reflective cholesteric displays are constructed with different surface treatments and their electro-optical properties are studied. A phenomenological theory is developed to model the angular dependence of the reflectivity of the displays.

Holographic Reflective Liquid-Crystal Display
A. G. Chen, K. W. Jelley, G. T. Valliath
Motorola Corporate Manufacturing Research Center, Schaumburg, IL
W. J. Molteni, P. J. Ralli, M. M. Wenyon
Polaroid Corp., Cambridge, MA
full paper

A new "holographic PDLC" device was optimized to attain bright reflection and low-voltage operation. Key features include up to two to three times improvement in brightness and contrast and elimination of image degradation due to glare. Compared with earlier versions, the reflection spectrum width is doubled and operating voltage halved by modifying LC and polymer materials. This device appears promising for active-matrix reflective color display applications.



Optimization of Holographic PDLC for Reflective Color Display Applications
K. Tanaka, K. Kato, M. Date, S. Sakai
NTT Interdisciplinary Research Laboratories, Tokyo, Japan
full paper

A newly developed "holographic PDLC" device was optimized to attain bright reflection and low voltage operation, making it suitable for a display device. A reflective active-matrix display consisting of 32x32 pixels on an area of 1.3x1.3 inches was fabricated.



The Role of Surface Azimuthal Anchoring in the Electro-Optic Response of PDLC Films
Y. Ji, J. R. Kelly
Department of Physics and Liquid Crystal Institute, Kent State University, Kent , OH
full paper

Experiments measuring the surface azimuthal anchoring energy between E7 and a thin film of the polymer polyvinylformal show an exponential decrease in the azimuthal surface anchoring above the transition temperature that correlates with a dramatic drop in the PDLC switching voltage and increase in its turn-off time. The polymer surface dynamics appear to play a dominant role in determining the surface anchoring behavior. The impact on PDLC electro-optic response is discussed.



Brightness Enhancement of Reflective Polymer-Dispersed LCDs
J. D. LeGrange, T. M. Miller, P. Wiltzius, K. R. Amundson, J. Boo, A. Van Blaaderen, M. Srinivasarao, A. Kmetz
AT&T Bell Laboratories, Murray Hill, NJ
full paper

The reflectance of a polymer dispersed liquid crystal display is enhanced by a brightness-enhancement film (BEF) by more than a factor of 2. Both laser backscattering measurements and contrast and reflectance measurements of displays in diffuse light show that a thin PDLC with a BEF exhibits brightness comparable to a thick PDLC cell, without requiring high voltages. The brightness enhanced PDLC reflects 33% of the incident light, making it more than a third as bright as photocopier paper. The disadvantage of the BEF, however, is that it reduces the contrast of the display at oblique viewing angles.



Large-Size Reflective Mosaic Displays Made of Self-Contained ECD Dots: Driving with Reduced Current Demands
B. Warszawski
Polyvision France, Paris, France
full paper

A reflective mosaic display structure based on the reversible electroplating of a metal black has been developed for signage and large-area displays. The display is made of independent self-contained dots secured to a supporting board bearing the driving conductor network and interconnected by bridges of conductive pastes. To reduce the current demands resulting from the high peak current pulse initiation the dot writing (electroplate nucleation pulse), multiplexing can be performed without loss of contrast thanks to the intrinsic matrix addressability of the technology and its memory. A feasibility prototype, comprising twenty mosaic modules made each with 35 dots (dot pitch: 1.4 cm; fill factor: 63%), is driven with a single character 5x7 matrix driving electronics switched from module to module; the maximum current demand is maintained under 1 Amp. The readability of the display has been tested in a wide range of indoors and outdoors illumination conditions and viewing angles.



A Color STN-LCD for Video Display Using Amplitude-Modulation MLS Technology
Y. Hirai, A. Nakazawa, K. Kawaguchi, H. Motegi, H. Koh, T. Kuwata, Y. Nakagawa
Asahi Glass Co., Ltd., Research Center, Yokohama, Japan
T. Ohbiki, M. Noguchi
Asahi Glass Co., Ltd., Electronic Products General Division, Chiyoda, Japan
H. Araki
Optrex Corp., Tokyo, Japan
full paper

A fast, 50 ms, VGA color STN display using multi-line selection has been developed. 32 gray levels were obtained using an amplitude-modulation (AM) method which simplifies the circuit architecture compared with the conventional frame-rate control technique. A contrast ratio of 40:1 was obtained.



Investigation of the Active Drive Method for STN-LCDs
T. Otani, K. Kumagawa, K. Nakanishi, M. Matsunami
Matsushita Electric Industrial Co., Ltd., LCD Development Center, Osaka, Japan
Y. Fukui, T. Matsumoto
Matsushita Electric Industrial Co., Ltd., Audio and Video Research Laboratory, Osaka, Japan
full paper

An optimal orthogonal row function set for the active drive method has been developed which uses a normalized Hadamard matrix expanded into three levels with randomly reversed element polarities. A new gray-shading technique is reported which reduces the column voltage and power consumption by dispersing the gray-shade correction term.



Dynamic Drive for Bistable Reflective Cholesteric Displays: A Rapid Addressing Scheme
X.-Y. Huang, D.-K. Yang, P. J. Bos, J. W. Doane
Liquid Crystal Institute and Department of Physics, Kent State University, Kent, OH
full paper

A novel, three stage drive scheme has been developed which dramatically reduces the line address time of the cholesteric display below 1 ms. This scheme takes advantage of the rapid transition of the cholesteric liquid crystal from the homeotropic state to the transient planar state. The voltage wave form is designed to implement this scheme in a high resolution passive matrix display which makes possible a 1000-line A4-sized "electronic newspaper".



Switching Mechanism of Bistable Reflective Cholesteric Displays
D.-K. Yang, Z.-J. Lu
Liquid Crystal Institute and Department of Physics, Kent State University, Kent, OH
full paper

A theoretical model to explain the switching behavior of bistable reflective cholesteric displays has been developed. Experimentally we have used optical reflection to investigate the dynamics of the transitions among the reflecting planar state, scattering focal conic state and transparent homeotropic state. The experimental results are shown to verify the model.



Novel LCD Color Projectors Based on Cholesteric Filters
J. Fünfschilling, M. Schadt
F. Hoffmann-LaRoche, Ltd., Basel, Switzerland
full paper

Two different video color projection concepts with single light beams, based on cholesteric liquid crystal filters and LC modulators, are proposed: a sequential color switching system with only one pixelated LC panel and a highly compact, bright design with three stacked LC panels, one for each color.

An Optically Active Diffractive Device for a High-Efficiency Light Valve
P. J. Bos, J. Chen, J. W. Doane
Liquid Crystal Institute, Kent State University, Kent, OH
B. Smith, C. Holton, W. Glenn
Florida Atlantic University, Boca Raton, FL
full paper

A new type of a liquid crystal diffractive liquid crystal light valve is proposed in which oppositely twisted stripes of nematic liquid crystal material are defined by a patterned alignment layer. The device demonstrates polarization independent diffraction without the need for high resolution patterning of electrodes.



Delayed Appearance of STN-LCD Cosmetic Defects Due to Conductive Contaminants
A. R. Kmetz, J. Y. Boo
AT&T Bell Laboratories, Murray Hill, NJ
T. Solikin
AT&T Global Information Solutions, Atlanta, GA
full paper

Particulate contamination in STN displays, innocuous at the time of manufacture, has been found to cause cosmetic defects a year later. Bright spots correspond to regions of reduced threshold. Low-frequency transient response shows that conductivity is highest near the particles, suggesting that they act as sources for gradual diffusion of ionic dopant.



Overview of the Conduction Regimes in LCDs
B. Maximus, C. Colpaert
ELIS, University of Ghent, Ghent, Belgium
full paper

Different conduction regimes are shown to exist, depending upon ion concentration. Above the space charge limit, conduction with the use of a leakage resistor is described.



STN Alignment on Rib-Spaced Plastic LCD Substrate
T. J. Gardner, R. P. Wenz
3M Materials Application Laboratory, St. Paul, MN
full paper

STN alignment issues in low-temperature preimidized polyimide alignment layers on plastic substrates incorporating an embossed rib structure for gap control are reported. Alignment layer nonuniformities not common to planar LCD substrate can occur in the presence of ribs but are correctable by the proper choice of coating parameters.



Polarizer-Free Reflective Amorphous Chiral Nematic Guest-Host LCDs
H. Koimai, Y. Iimura, S. Kobayashi
Tokyo University of Agriculture & Technology, Tokyo, Japan
T. Hashimoto, T. Sugiyama, K. Katoh
Stanely Electric Co., Ltd., Kanagawa, Japan
full paper

A polarizer-free reflective guest host (GH) LCD has been fabricated using an amorphous chiral nematic liquid crystal as a host medium resulting in a reflectivity of 42% and a uniform wide viewing angle. This GH display is free from the appearance of hysteresis and stripe domains even through the twist angle is 300 degrees, and no pretilt exists. The contrast ratio is 3.4.



Polarized UV-Exposed Polyimide Films for Liquid-Crystal Alignment
J. L. West, X. Wang, Y. Ji, J. R. Kelly
Liquid Crystal Institute, Kent State University, Kent, OH
full paper

The alignment of liquid crystal materials using ultraviolet (UV) exposed polyimides is reported. The alignment is controlled by the polarization orientation of the UV radiation. The alignment is thermally stable, remaining unchanged after 12 hours at 120 degrees Celsius. The azimuthal anchoring energy is similar to rubbed polyimide films.



A High-Information-Content Reflective Cholesteric Display
M. Pfeiffer, D.-K. Yang, J. W. Doane
Liquid Crystal Institute, Kent State University, Kent, OH
R. Bunz, E. Lueder
University of Stuttgart, Stuttgart, Germany
M.-H. Lu, H. Yuan, C. E. Catchpole, Z. Yaniv
Kent Display Systems, Kent, OH
full paper

A 14 inch diagonal high resolution (100 dpi) cholesteric liquid crystal display has been fabricated. Bistability allows the full page size display with a resolution of 1152 x 896 pixels to be passively addressed. Performance features in applications as electronic books or newspapers are reviewed.

A Full-Color Video-Rate Anti-Ferroelectric LCD with Wide Viewing Angle
Y. Yamada, N. Yamamoto, K. Nakamura, N. Koshobu, S. Ohmi, R. Sato, K. Aoki, S. Imai
Nippondenso Co., Ltd., Aichi, Japan
full paper

A 6 in diagonal, full color, antiferroelectric LCD (AFLCD) compatible with TFT-LCDs has been developed. Both the driving method and the full color technique using multi-domain switching have been achieved. The AFLC display shows high contrast and extremely wide viewing characteristics without color inversion.



Viewing-Angle-Enhancement System for LCDs
S. Zimmerman, K. Beeson, M. McFarland, J. Wilson, T. J. Credelle, K. Bingaman, P. Ferm
AlliedSignal, Inc., Micro Optical Devices, Morristown, NJ
J. T. Yardley
AlliedSignal, Inc., Corporate R&T, Morristown, NJ
full paper

A new enhancement system for transmissive LCDs has been developed which eliminates contrast inversion and color shift with viewing angle. Contrast ratios of greater than 50:1 have been demonstrated at ±60°(vertical and horizontal) on an active matrix LCD. The operating principles of the collimating backlight and low reflectivity diffusing screen are described.



Properties of the OCB Mode for Active-Matrix LCDs with Wide Viewing Angle
T. Miyashita, C.-L. Kuo, M. Suzuki, T. Uchida
Tohoku University, Sendai, Japan
full paper

The "Optically compensated bend mode" (OCB-mode) for active matrix LCD with wide viewing angle and fast response is proposed. Detailed properties of this OCB-mode: full color capability, reverse tile disclinations at the pixel edge, and temperature dependence are described. From the result, the OCB-mode is confirmed to be promising for the high-end of future LCD.



Viewing Angle and Color-Uniformity Optimization of the Pi Cell
M. F. Flynn
Kaiser Electronics, San Jose, CA
P. J. Bos
Liquid Crystal Institute, Kent State University, Kent, OH
full paper

The pi cell has been shown to offer wide viewing angle and fast switching in AMLCD applications. The performance metric numerical optimization method was applied to the pi cell. Simultaneous optimization of contrast, luminance and color uniformity are carried out with variations performed with respect to compensation layer values and orientation, as well as LC cell thickness.



Four-Domain TN-LCD Fabricated by Reverse Rubbing or Double Evaporation
J. Chen, P. J. Bos, D. R. Bryant, D. L. Johnson, S. H. Jamal, J. R. Kelly
Physics Department and Liquid Crystal Institute, Kent State University, Kent, OH
full paper

Four-domain (4-D) twisted nematic (TN) liquid crystal display (LCD) device have been developed by the reverse rubbing and the double SiOx oblique evaporation techniques in which a single photolithography and two rubbing or two SiOx oblique evaporation processes for each plates are involved. A 4-D structure is reported which is composed of two left-hand TN and two right-hand TN subpixels. One of the two identical handedness subpixels is rotated 180 degrees respect to the other. This effect makes these four domains mutually compensate each other optically to provide a wide angle of view with no gray scale inversion. Viewing angle and contrast ratio measurement data for 4-D TN LCD's are presented.
Key words: four-domain, twisted nematic, liquid crystal display, gray scale and viewing angle



No-Rub Multi-Domain TFT-LCD Using Surrounding-Electrode Method
N. Koma, Y. Baba, K. Matsuoka
Sanyo Electric Co., Ltd., Gifu, Japan
full paper

A TFT-LCD for wide viewing angle has been fabricated without rubbing by forming the electrode around the display picture elements and controlling the tilting direction of LC by the electric-field induced by the surrounding electrode.



A Well-Controlled Tilted-Homeotropic Alignment Method and a Vertically Aligned Four- Domain LCD Fabricated by This Technique
H. Vithana, Y. K. Fung, S. H. Jamal, R. Herke, P. J. Bos, D. L. Johnson
Liquid Crystal Institute, Kent State University, Kent, OH
full paper

A new method to obtain tilted homeotropic alignment with small pre-tile angles has been developed using oblique vacuum evaporation of SiOx. Pre-tilt angles in the range (0-5)° are obtained with this method without sensitivity to the deposition angle which can be varied between (20°-70°) without imparting substantial variation. Using this technique a vertically aligned four-domain TN-LCD was fabricated. Due to the different but symmetric director configurations of the molecules in these four domains in the ON-state, this display gives very good electro-optic characteristics without any twist or tilt defects.



TN-LCD with Quartered Subpixels Using Polarized UV-Light-Irradiated Polymer Orientation Films
T. Hashimoto, T. Sugiyama, K. Katoh
Stanley Electric Co., Ltd., Kanagawa, Japan
T. Saitoh, H. Suzuki, Y. Iimura, S. Kobayashi
Tokyo University of Agriculture & Technology, Tokyo, Japan
full paper

A TN-LCD with a wide and homogeneous viewing angle characteristics and an grayscale capability has been fabricated by irradiating photo-polymer polyvinyl cinnamate (PVCi) films with polarized UV light to yield quartered subpixels. A unidirectional LC alignment accompanying pretilt angle is attained with a combination of double exposure and slanted irradiation resulting in a reverse tilt disclination free mono-domain TN-LCD. The position and shape of reverse tilt disclinations are completely controlled.



Investigation of the Mechanism of the Surface-Induced Alignment of Liquid Crystals by Linearly Polymerized Photopolymers
J. Chen, B. Cull, P. L. Bos, D. L. Johnson
Physics Department and Liquid Crystal Institute, Kent State University, Kent, OH
M. Schadt
F. Hoffman-La Roche, Basal, Switzerland
full paper

A theoretical model of the mechanism of the surface-induced alignment of liquid crystals (LC) by the linearly polymerized photopolymers (LPP) has been proposed. Based on this model, the retardation of these systems versus the exposure time of linearly polarized UV light is calculated. The available experimental data of poly(viny)4-methoxycinnamate(PVMC) and poly(viny) cinnamate(PVC) systems are well fitted by this model. This model also indicates the LC aligning ability and anchoring direction in these systems can be well controlled by UV intensity, exposure time and its polarization direction.
Key words: linearly polymerized photopolymers, alignment layer for LC, anchoring of LC



Simulation of Display Characteristics of TN-LCD with Curvature Rubbing Pattern
X. Shao, X. Huang, Z. Ling, Z. Wang, K. Ma, T. Yu
Chinese Academy of Sciences, Changchun, People's Republic of China
full paper

A novel method to extend the viewing angle of TN-LCD is proposed by making LCD cells with substrates rubbed using a curvature pattern, CR-TN-LCD. The display was analysed by computer simulation. The results show that viewing angle gray level capability are improved.



Alignment of Ferroelectric Liquid-Crystal Molecules by Liquid-Crystalline Polymer
S.-H. Jin, S.-E. Chung, S.-W. Kang, J.-S. Lee, J.-C. Lee
Samsung Advanced Institute of Technology, Suwon, Korea
J.-G. Park
SAIT, San Diego, CA
full paper

Liquid crystalline polymer (LCP) was used for the alignment of ferroelectric liquid crystal (FLC) molecules. The surface morphology of the resulting polymeric thin film was observed by the atomic force microscope. Uniform alignment of FLC molecules on the surface of LCP thin film is obtained without the formation of microgroove structures. A contrast ratio of sample cell of 23:1 and a good memory capability is obtained. After AC field stabilization at 20V, the typical stripe-shaped pattern appears.



Computer Simulation of Director Profile in Three-Dimensional Electric Field
M. Kitamura
Shintech, Inc., Yamaguchi, Japan
full paper

A computer program for simulating the behavior of the nematic liquid crystal director in three dimensional electric field was developed. The degradation of optical characteristics of a pixel caused by lateral components of the electric field can be evaluated. A discussion of the theoretical background of the calculation and an example of its application to usual TFT display is provided.



LCD Modeling as a Display Characterization Tool
R. Herke, S. H. Jamal, J. R. Kelly
Liquid Crystal Institute, Kent State University, Kent, OH
full paper

A user friendly TN and STN LCD modeling program based on the Berreman 4x4 matrix method is described. This type of model is not only useful for design work but can also serve as a versatile LCD characterization tool. The optical parameters necessary to produce an accurate model at the pixel level are discussed briefly, and examples are given of the models use in the determination of surface pretilt, cell thickness, and film retardation.



A General Method to Solve the Deformation Profile of Chiral Nematic LCDs with Asymmetric Pretilt
C.-J. Chen, M. I. Nathan
University of Minnesota, Minneapolis, MN
A. Lien
IBM T. J. Watson Research Center, Yorktown Heights, NY
full paper

A general method is presented to solve the deformation profile of chiral nematic liquid crystal display with asymmetric pretilt for the strong anchoring case. It can also be used to determine the most stable state if there exist two or more deformation profiles under a given condition. This method is applied to calculate and determine the director configurations of asymmetric twist nematic cells, hybrid cells and pi-cells.



Temperature-Independent Transmission of PDLC Films
A. Y. G. Fuh, J. W. Doane
Liquid Crystal Institute, Kent State University, Kent, OH
G. L. Lin, C. Y. Huang, M. S. Tsai
National Cheng-Kung University, Taiwan, Republic of China
full paper

Polymer-dispersed liquid crystal (PDLC) films based on TL205 (liquid crystal)/PN393 (polymer) mixtures are fabricated to exhibit either high on-state transmission or to possess a linear transmission vs. temperature curve over a wide temperature range depending upon the UV polymer curing intensity.



Phase-Matched Biaxial Compensation Film for LCDs
S.-T. Wu
Hughes Research Laboratories, Malibu, CA
full paper

Guidelines for selecting a phase-matched biaxial compensation film for a full-color liquid crystal display (LCD) are developed. The polycarbonate and spin-coated polyimide films show an excellent phase matching property with LC cell over a wide range of viewing angle and wavelength.



Optics of Nematic Liquid-Crystal Cells in Circularly Polarized Light
J. A. M. M. van Haaren, J. M. A. van den Eerenbeemd
Philips Research Laboratories, Eindhoven, The Netherlands
full paper

The electro-optical properties of nematic layers between quarterwave retarders were studied. It is concluded that the twisted nematic effect in circularly polarized light can only be used in a cell with a thickness of about 2 µm and that the bright state of such a cell is relatively dark.



A High-Contrast Wide-Viewing-Angle Low-Twisted-Nematic LCD Mode
J.-I. Hirakata, H. Abe, I. Hiyama, K. Kondo
Hitachi Research Laboratory, Ibaraki, Japan
H. Madokoro
Hitachi Device Engineering Co., Ltd., Chiba, Japan
full paper

A new LCD mode with wide viewing angle characteristics in high contrast displays was developed by utilizing a low retardation of 0.38 µm, a low twist angle (70°) and a small retardation compensator (23nm). The grayscale inversion range was extended from 27° to 30° verticle and from 42° to 73° horizontal in comparison with 90° TN-LCDs. A 100:1 contrast ratio was achieved.



The Performance of a Liquid-Crystal Polymer Film as an Optical Compensator for a Fast-Response STN-LCD
S. Nishimura, T. Toyooka, T. Matsumoto, H. Itoh, T. Satoh
Nippon Oil Co., Ltd., Yokohama, Japan
S. Takikawa
Nippon Petrochemicals Co., Ltd., Kanagawa, Japan
full paper

A liquid crystal polymer film (LC film) was developed and its mass-producing method was established. The LC film independently controls three optical parameters; twist angle, retardation and wavelength dependence (dispersion) of birefringence. The dispersion of the LC film as a compensator provides complete compensation in a fast response STN cell. High contrast is achieved by combining active addressing with the compensating LC film in the fast response cell.



Display Characteristics of Amorphous ECB LCD: Polymer Stabilized Amorphous ECB Cell
H. Jing, X. Huang, R. Sun, K. Ma, H. Ren, X. Zhu, J. Yuan
Changchun Institute of Physics, Chinese Academy of Sciences, P. R. China
full paper

The new color display, a-HAN LCD, was fabricated with nonrubbing technology. The a-HAN is simpler to produce and has improved azimuthal symmetrical viewing-angle characteristics.


Display Characteristics of Amorphous ECB LCD: Hybrid Aligned Nematic Cell
R. Sun, X. Huang, K. Ma, H. Jing, J. Yuan
Changchun Institute of Physics, Chinese Academy of Sciences, P. R. China
full paper

The new color display, a polymer stabilized amorphous ECB (PS-a-ECB) LCD, was fabricated with non-rubbing technology resulting in a reduction of driving voltage. The PS-a-ECB is stable and has smaller multidomains.



Axially Symmetric Aligned Microcell (ASM) Mode: Electro-Optical Characteristics of New Display Mode with Excellent Wide Viewing Angle
N. Yamada, S. Kohzaki, F. Funada, K. Awane
Sharp Corp., Nara, Japan
full paper

The new LCD display mode (ASM mode) was developed with an axially symmetric orientation of liquid crystal molecules and a micro-cell structure in each pixel. The elecro-optic characteristics of this mode afford high contrast (CR>or=200, at normal direction) and the wide viewing angle characteristics without contrast inversion (±60° in both vertical and horizontal directions).



Polarizer-Free Reflective Spiral Polymer-Aligned Nematic GH-LCDs
H. Takatsu, Y. Umezu, H. Hasebe, K. Takeuchi
Dainippon Ink & Chemicals, Inc., Saitama, Japan
K. Suzuki, Y. Iimura, S. Kobayashi
Tokyo University of AT&T, Tokyo, Japan
full paper

A polarizer free, reflective, spiral polymer, aligned nematic, (SPAN), guest host LCD exhibiting low operation voltage, high luminance, good contrast ratio, and good viewing angle characteristics has been fabricated by photo-polymerization of a chiral acrylate monomer in a nematic liquid crystalline host including a black dichroic dye.