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View Session
- Front Matter: Volume 7618
- Emissive, Headmount and Projection Displays
- 3D Displays
- Nonlinear Optics and Lasing
- Nanoparticles Self-Assembly, Dispersion and Manipulation
- Spatial Light Modulators
- Bio-Active, Bio-Inspired Materials and Applications
- New Materials and Substrates
- Polymer-Stabilized LCDs
- Dye-Doped Devices
- Holography and Holographically-Formed PDLCs
- Poster Session
Front Matter: Volume 7618
Front Matter: Volume 7618
Show abstract
This PDF file contains the front matter associated with SPIE
Proceedings Volume 7618, including the Title Page, Copyright
information, Table of Contents, and the Conference Committee listing.
Emissive, Headmount and Projection Displays
Design of a free-form single-element head-worn display
Show abstract
Compact and lightweight optical designs achieving visually acceptable image quality, field of view, eye clearance, eye
box diameter and operating across the visible spectrum, are the key to the success of next generation head-worn displays.
There have been several approaches in the design of head-worn displays including holographic optical elements and
laser scanner systems. For example, Minolta has pursued a monochromatic display (green) with a 3 mm exit pupil
realized by a 3.4 mm thick light guide with a holographic optical element to achieve an eyeglass form-factor head-worn
display [1]. Our approach in this paper is to investigate the field of view, eyebox diameter, and the performance limit of
a single element magnifier comprised of freeform surfaces. The surface shape is a major variable in such a constrained
system with respect to the optimization degrees of freedom.
Typical optical surfaces are functions mapping vectors in R2 to real numbers representing the sag of the surface. A
majority of optical designs to-date have relied on conic sections to which are added polynomials as the functions of
choice. The choice of conic sections is easily justified, since conic sections are stigmatic surfaces under certain imaging
geometries. The choice of polynomials from an image quality analysis point of view is understood since the wavefront
aberration function is typically expanded in terms of polynomials. Therefore, a polynomial surface description may link
a designer's understanding of the wavefront aberrations and the surface shape. However, from the point of view of shape
optimization and representation, polynomial shape descriptions can be challenged. In Section 2, we briefly describe the
radial basis function approach to represent freeform optical surfaces. In Section 3, we apply the RBF to design a single
element see-through compatible head-worn display.
Next-generation head-mounted display
James P. McGuire Jr.
Show abstract
Head Mounted Displays (HMDs) have been utilized by the military for various applications since the 1980's. In the
1990's, this technology migrated to the consumer market. Most of these early systems suffered the major drawback
that they were "look-at" versus "see through" systems, which prevented the user from seeing their environment.
This reduced the utility of the devices and could potentially lead to safety issues.
This presentation discusses the optical design of a novel see-through High Definition display device with a 40
degree field of view.
High power high bandwidth laser diode driver for next generation laser projectors
Andreas Streck,
Wilhelm Stork,
Armin Wagner
Show abstract
Employed in projection domes or in general, applications involving spherical surfaces, like professional flight simulators
or automobile head-up displays, laser projectors offer great benefits over techniques involving liquid crystals or digital
mirror devices. With the development of red and especially blue laser diodes with output powers in the range of several
Watts, new prospects have been opened for compact and cheap laser projectors by direct modulation of the lasers with
the pixel rate in scanning systems.
In this paper, the requirements and challenges for the laser driver circuits are highlighted. For displaying high definition
graphics and video resolutions with pixel rates above 100 MHz, the drivers need to provide very high bandwidth
broadband modulation capability. Additionally high output currents in the Ampere region are required when driving high
power laser diodes. Focusing on the parasitic effects of the laser diodes packages and the interconnection between
drivers and lasers, restrictions and solutions for achieving the combination of these two requirements are shown. A
1.5 A, 100 MHz driver module which was developed under derived design rules is presented and test results are given
for high power diodes in TO-Can and C-Mount packages.
3D Displays
Overview of 3D/2D switchable liquid crystal display technologies
Show abstract
Various techniques for three-dimensional/two-dimensional switchable liquid crystal displays are introduced. Key
component of the three-dimensional/two-dimensional switchable displays is an active optical device with an on/off
function. Liquid crystal has electrically controllable optical properties, making it ideal for the active optical devices. The
applications of the liquid crystal to various three-dimensional/two-dimensional switchable displays including glassestype
stereoscopic displays, autostereoscopic displays, and integral imaging displays are reviewed.
Static 3D image space
Show abstract
As three-dimensional (3D) techniques continue to evolve from their humble beginnings-nineteenth century stereo
photographs and twentieth century movies and holographs, the urgency for advancement in 3D display is escalating, as
the need for widespread application in medical imaging, baggage scanning, gaming, television and movie display, and
military strategizing increases. The most recent 3D developments center upon volumetric display, which generate 3D
images within actual 3D space. More specifically, CSpace volumetric display generates a truly natural 3D image
consisting of perceived width, height, and depth within the confines of physical space. Wireframe graphics enable
viewers a 360-degree display without the use of additional visual aids. In this paper, research detailing the selection and
testing of several rare earth, single-doped, fluoride crystals, namely 1%Er: NYF4, 2%Er: NYF4, 3%Er: NYF4 ,
2%Er:KY3F10, and 2%Er:YLF, is introduced. These materials are the basis for CSpace display in a two-step twofrequency
up-Conversion process. Significant determinants were tested and identified to aid in the selection of a suitable
medium. Results show that 2%Er: NYF4 demonstrates good optical emitted power. Its superior level of brightness makes
it the most suitable candidate for CSpace display. Testing also proved 2%Er: KY3F10 crystal might be a viable medium.
Resolution analysis of Fourier hologram using integral imaging and its enhancement
Show abstract
The resolution of the reconstructed object from the Fourier hologram that is generated from multiple view images is
analyzed in this paper. We found that the maximum view angle and the wavelength limit the maximum frequency of the
reconstructed object. The relationship between the bandwidth of the object and the lens pitch of the lens array affects the
aliasing of the reconstruction. All these four parameters determine the resolution of the reconstruction from the Fourier
hologram. Based on these analyses, we propose a lens array shift method to enhance the resolution of the reconstructed
object from the Fourier hologram. By shifting the lens array, multiple sets of element images are obtained, and high
spatial density element image is combined from the multiple sets of element images. The resolution enhanced
reconstruction of the object can be obtained from the Fourier hologram of the combined element images. The principles
are verified by experiment.
A new method for laser speckle suppression
Show abstract
The objective of this work is the suppression of speckles in an image illuminated by a
remote laser. This is accomplished by a novel method in which the illuminating laser
beam propagates through a multimode fiber dithered at an arbitrary section, then passes
through a microlens array prior to illuminating the image generator. Thereby the speckle
contrast is reduced to its minimum value for dithering frequencies of at least 25 Hz,
attaining a magnitude speckle contrast of less than 12%, and illumination homogeneity
across the illumination filed of less than 20%.
An artifact-metrics which utilizes laser speckle patterns for plastic ID card surface
Show abstract
Artifact-metrics is an automated method of authenticating artifacts based on their measurable intrinsic characteristics
such as microscopic random-patterns and the like which are emerging in their manufacturing process. They are very
difficult to copy and control even for legal manufacturers. This paper describes the feasibility of an artifact-metric
system using laser speckle patterns of the surface of security documents. Speckle patterns of the surface differ from each
object depending on their microscopic geometry; they can be authenticated automatically by some matching algorithm
that compares the input with the previously enrolled data. Our system consists of a laser diode and a CMOS camera
which are attached firmly to a rigid metal frame and a matching algorithm by correlation coefficient method. To improve
matching accuracy we investigate the influence of width and incident angle of the laser beam and aperture size and
shooting angle for the camera on the matching accuracy through matching tests using 100 of ID cards. As a result, we
found that aperture size of the camera and width of the laser are part of important factors for matching accuracy. Also,
we achieved equal error rate of 0.1% using data size of 16 square pixels for speckle patterns.
Nonlinear Optics and Lasing
Liquid crystal waveguides: new devices enabled by >1000 waves of optical phase control
Show abstract
A new electro-optic waveguide platform, which provides unprecedented voltage control over optical phase delays (>
2mm), with very low loss (< 0.5 dB/cm) and rapid response time (sub millisecond), will be presented. This technology,
developed by Vescent Photonics, is based upon a unique liquid-crystal waveguide geometry, which exploits the
tremendous electro-optic response of liquid crystals while circumventing their historic limitations. The waveguide
geometry provides nematic relaxation speeds in the 10's of microseconds and LC scattering losses that are reduced by
orders of magnitude from bulk transmissive LC optics. The exceedingly large optical phase delays accessible with this
technology enable the design and construction of a new class of previously unrealizable photonic devices. Examples
include: 2-D analog non-mechanical beamsteerers, chip-scale widely tunable lasers, chip-scale Fourier transform
spectrometer (< 5 nm resolution demonstrated), widely tunable micro-ring resonators, tunable lenses, ultra-low power (<
5 microWatts) optical switches, true optical time delay devices for phased array antennas, and many more. All of these
devices may benefit from established manufacturing technologies and ultimately may be as inexpensive as a calculator
display. Furthermore, this new integrated photonic architecture has applications in a wide array of commercial and
defense markets including: remote sensing, micro-LADAR, OCT, FSO, laser illumination, phased array radar, etc.
Performance attributes of several example devices and application data will be presented. In particular, we will present a
non-mechanical beamsteerer that steers light in both the horizontal and vertical dimensions.
Nanoparticles Self-Assembly, Dispersion and Manipulation
Quantum dot self-assembly in liquid crystal media
Show abstract
In recent years the dispersion and directed assembly of nano-particles in liquid crystal media has proved an interesting
field for investigation and one that may yield new hybrid materials for optical applications and fundamental research. In
this paper, we investigate the dispersion of quantum dots in different liquid crystal phases, looking at aggregation and
pattern formation. Quantum dot self-assembly in liquid crystals is dependent on particle surface properties and
concentration in the liquid crystal medium. By varying these parameters we observe some fascinating structures and
phase behavior using polarized optical microscopy and fluorescence microscopy.
Spatial Light Modulators
30 to 50 ns liquid-crystal optical switches
M. W. Geis,
R. J. Molnar,
G. W. Turner,
et al.
Show abstract
The optical switching times of liquid-crystal cells using 5CB, 5OCB and PCH5 liquid crystal materials have been
characterized as a function of applied voltage, V, and temperature, T. The transition time from 90 to 10 % transmission
scales as V-2 and is limited to 50 to 30 ns by the breakdown electric field, ~ 106 V cm-1 of the liquid crystal. The time
from the initial voltage step to 90 % transmission, delay time, decreases with increasing voltage and approaches a
constant value at higher electric fields, >105 V cm-1. Both the transition and delay times decrease with increasing
temperature. The minimum transition times at temperatures a few degrees below the nematic-isotropic temperature are
32, 32, and 44 ns and delay times are 44, 25 and 8 ns for 5CB, 5OCB, and PCH5 respectively.
Electroactive super elongation of carbon nanotube clusters in liquid crystal medium and its display application
Show abstract
Carbon nanotubes (CNTs) can exist as clusters whenever doping amount in nematic liquid crystal (LC) mixture exceeds
critical point. Based on experimental observation of electric field-dependent shape of the CNT cluster, it elongates along
the field direction and its original morphology of the cluster is restored after the removal of the field. The elongation was
fully reversible only below a certain breakdown field. Both clusters and elongated CNTs were observed under nonpolarized
and polarized light. The cluster absorbs incident light completely while the elongated one absorbs light
propagating along the long axis only. Utilizing the field-controlled cluster, light modulation for display application is
possible.
Bio-Active, Bio-Inspired Materials and Applications
Nonequilibrium fluctuations in metaphase spindles: polarized light microscopy, image registration, and correlation functions
Jan Brugués,
Daniel J. Needleman
Show abstract
Metaphase spindles are highly dynamic, nonequilibrium, steady-state structures. We study the internal fluctuations
of spindles by computing spatio-temporal correlation functions of movies obtained from quantitative
polarized light microscopy. These correlation functions are only physically meaningful if corrections are made
for the net motion of the spindle. We describe our image registration algorithm in detail and we explore its
robustness. Finally, we discuss the expression used for the estimation of the correlation function in terms of the
nematic order of the microtubules which make up the spindle. Ultimately, studying the form of these correlation
functions will provide a quantitative test of the validity of coarse-grained models of spindle structure inspired
from liquid crystal physics.
New Materials and Substrates
Plastic substrate technologies for flexible displays
Show abstract
A novel plastic substrate for flexible displays was developed. The substrate consisted of a polycarbonate (PC) base film
coated with a gas barrier layer and a transparent conductive thin film. PC with ultra-low intrinsic birefringence and high
temperature dimensional stability was developed for the base film. The retardation of the PC base film was less than 1
nm at a wavelength of 550 nm (film thickness, 120 μm). Even at 180 °C, the elastic modulus was 2 GPa, and thermal
shrinkage was less than 0.01%. The surface roughness of the PC base film was less than 0.5 nm. A silicon oxide (SiOx)
gas barrier layer was deposited on the PC base film by a DC magnetron reactive sputtering method. In addition, a unique
organic-inorganic hybrid material is coated on the SiOx to further improve the gas-barrier performance. The water vapor
transmission rate of the film was less than 0.05 g/m2/day at 40 °C and 100% relative humidity (RH), and the permeation
of oxygen was less than 0.05 cc/m2•day•atm at 40 °C and 90% RH. Indium Zinc Oxide optimized for the plastic
substrate was deposited on the other side of the SiOx film by the DC magnetron sputtering method. The transmittance
was 87% and the resistivity was 3.5×10-4 ohm•cm.
Micro-actuators prepared from liquid crystalline elastomers in a microfluidic setup
Show abstract
In this paper we demonstrate the preparation of monodisperse particles from a liquid crystalline elastomer with a
preferred director orientation. For this we use a microfluidic setup to create droplets from a liquid crystalline
monomer which are polymerized in the liquid crystalline phase while flowing. When the obtained particles are
heated above the transition temperature of the nematic phase, they show a reversible shape change from
spherical to cigar-like. We show, that we can control the size as well as the polydispersity of these microactuators.
If the particles are prepared in non-flowing conditions, no or an undefined shape change is observed.
Particles polymerized in the isotropic phase show no shape deformation as well. Additionally we provide an
experimental proof for the stability of these structures versus acidic and basic conditions.
Polymer-Stabilized LCDs
Polymer-networked liquid crystal cell for omni-directional viewing-angle switching
Show abstract
A novel method for switching the viewing-angle of a liquid crystal display is proposed by using a polymernetworked
liquid crystal cell in combination with a collimated backlight system. The bright state for a wide
viewing-angle is obtained aligning liquid crystals randomly in polymer-networked structure, which diffuses a
collimated backlight. The liquid crystals homogeneous-aligned by in-plane switching are operated as the
bright state for a narrow viewing-angle since a collimated backlight passes through the liquid crystal layer
intactly. It is demonstrated experimentally that the viewing-angle can be controlled omni-directionally
without an additional panel or an additional backlight system.
Liquid crystal-directed polymer nanostructure for vertically aligned nematic cells
Show abstract
We demonstrate a fast switching surface polymer-assisted vertically aligned (SPA-VA) liquid crystal (LC) cell. The
deposition of the polymer nano spikes as a part of the alignment layer is achieved by polymerizing a small amount of a
reactive monomer in vertically aligned liquid crystal in the absent of an applied voltage. The phase-separated polymer
localized at the both substrate surfaces and formed nano-sized spikes. These polymer nano-spikes act as internal surface
alignment layers and enhance the speed of field-induced reorientation of liquid crystal molecules.
Dye-Doped Devices
Guest-host liquid crystal devices for adaptive window application
Show abstract
In this paper we present the work performed by AlphaMicron in the area of Adaptive Window application
using a guest-host liquid crystal configuration combined with liquid crystal based solar concentrator and high
efficiency photovoltae. The system can be used for Zero-Energy Building applications by providing a
dynamic solar heat gain coefficient. This allows the reduction of the energy loss through windows in mixed
climate regions.
Band-tunable color cone lasing emission based on a dye-doped cholesteric liquid crystal film
Show abstract
This investigation reports for the first time a novel phenomenon, called band-tunable color cone lasing emission (CCLE),
based on a single-pitched one-dimensional photonic crystal-like dye-doped cholesteric liquid crystal (DDCLC) cell. The
lasing wavelength in the CCLE pattern is distributed continuously at 676.7-595.6 nm as the oblique angle increases
continuously from 0° to 50° relative to the helical axis. The variation of the lasing wavelength in the CCLE with the
oblique angle is consistent with that of the wavelength at the long-wavelength edge (LWE) of the CLC reflection band
(CLCRB) with the oblique angle. Simulation results obtained utilizing Berreman's 4×4 matrix method show that, at each
oblique angle, the associated group velocity and density of photonic state (DOS) are near zero and large at the shortwavelength
edge (SWE) and LWE of the CLCRB, respectively, and are in good agreement with experimental results.
The particularly strong lasing ring emission at a cone angle of ~35° can be explained to be likely due to a special effect
that, under the condition of overlap between the LWE of the CLCRB measured at 35° and the SWE of the CLCRB
measured at 0°, the LWE and SWE fluorescence propagating along 35° and 0°, respectively, may indirectly enhance
each other due to individual enhanced rate of spontaneous emission. Furthermore, the lasing band of the CCLE can be
tuned from long-wavelength (deep red~orange) to short-wavelength (orange~green) regions by changing the
concentration of the chiral or by the photo-irradiation on a DDCLC cell with a photoisoemerizable chiral dopant.
Reflective display based on biphotonic effect-induced phase transition in dye-doped cholesteric liquid crystals
Show abstract
This work studies the biphotonic effect in samples that are cholesteric liquid crystals (CLCs) doped with azo-C5. The
experimental results show that the photo-isomerization of azo-C5 not only changes the clearing point of the sample, but
also shifts the reflection band that is associated with the planar texture. Additionally, azo dye-doped CLCs (DDCLCs)
have bi-stable or tri-stable states, as determined by the ambient temperature. Photo-switching between these bi-stable/tristable
states is systematically studied. The result indicates that photo-addressing one of these states (planar, focal conic,
and isotropic states) using a low- or high-intensity Ar+ laser beam is feasible. The results thus obtained are used to
fabricate a photo-rewritable DDCLC display.
Holography and Holographically-Formed PDLCs
The dynamics of human sperm droplets on a liquid crystal and polymer composite film
Show abstract
A switchable surface using a liquid crystal and polymer composite film (LCPCF) based on phase separation
between liquid crystals (LC) and polymers after photopolymerization is developed recently. The wettability of
LCPCF is electrically tunable because of the orientation of liquid crystal directors anchored among the
polymer grains under an in-planed electric field. A water droplet on the top of LCPCF can be manipulated
under an inhomogeneous electric field on the LCPCF owning to the wettability gradient. The dynamics of a
droplet of human sperms on the LCPCF is demonstrated as well. Three motions of sperm droplets are
observed: the droplet collapse and the droplet stretch,. We found that the dynamics, concentrations, and
activities of spermatozoa, affect the motions of a sperm droplet. The potential applications of LCPCF are
polarizer-free displays, liquid lenses, and the microfluidic device in assisted reproductive technology (ART)
Evaluations of liquid crystal panel as a random phase modulator for optical encryption systems based on the double random phase encoding
Show abstract
A use of liquid crystal panels (LCPs) as a random phase modulator in the optical encryption system based on
the double random phase coding (DRPC) [Optics Letters, Vol.20, 767(1995)] is considered in the present paper.
Required phase modulation property of LCPs as random phase modulators in the DRPC are investigated by
computer simulations. It is found from simulation results that the required number of independent patches for
phase modulations must be greater than 128 × 128 pixels for LCPs with the maximum phase modulation of
1.55π radians. It is also found that the required maximum phase modulation can be reduced to 1.25π radians by
increasing the number of independent patches to 1024 × 1024 pixles. Experimental study using a commercially
available LCP (EPSON, HTPS LCP, L3P14Y-55G00) verified partially these simulation results.
Electrical tuning of two-dimensional honeycomb photonic lattices using holographic polymer dispersed liquid crystals
Show abstract
We report on the spectral transmittance and wavelength-dispersion properties of two-dimensional photonic lattices
using holographic polymer dispersed liquid crystals (HPDLCs) and demonstrate their electrical control.
A statistical thermodynamic model is employed to calculate spatial distributions of the formed polymer, liquid
crystal molecules and the resultant anisotropic refractive index distribution under three-beam holographic exposure.
The effect of multiple reflections inside an HPDLC film on the formed refractive index distribution is
also taken into account in the theoretical analysis. Measured transmittance spectra and wavelength-dispersion
angles are compared with the calculated results.
Ultrafast switching liquid crystals for next-generation transmissive and reflective displays
Show abstract
We describe wide temperature range bimesogenic chiral nematic liquid crystals with high flexoelectro-optic coefficients
(e/K),of the order of 2.0 CN-1 m-1, high switching angles, > 160° and 50-100μs response times, which may be used to give
gray scale devices in both the ULH texture, with an optimum optical in plane switch of 45° at fields of 2Vμm-1 depending
on helix pitch and suitable for LCoS devices, and in the USH or Grandjean texture with a unique optically isotropic "field
off" black state and contrast ratios of > 5000:1, using "in plane" electric fields, with switching times of the order of 200μs.
The new materials and devices give μs level to level switching and the real potential for colour filter free frame sequential
colour switching. Highly reflective Blue Phase devices, stable over a 90°C temperature range, in which an electric field is
used to switch the reflection from red to green, for example, will be described. Full RGB reflections may be obtained with
switching times of a few milliseconds. New surface and volume activated reflecting N* Grandjean texture devices will also
be described. Visible wavelength shifts of ~100nm are reported. These are activated by so called "command" surfaces or
nanoscopic ferroelectric inclusions and conventional transverse electric fields. Finally we will briefly mention potential
applications including high efficiency RGB liquid crystal laser sources.
High quality assembly of liquid crystal on silicon (LCOS) devices for phase-only holography
Show abstract
LCOS for phase-only holography is ideally made to better optical tolerance than that for conventional
amplitude modulating applications. Die-level assembly is suited to custom devices and pre-production
prototypes because of its flexibility and efficiency in conserving the silicon backplane. Combined with
automated assembly, it will allow high reproducibility and fast turnaround time, making a way for
pre-production testing and customer sampling before mass production. Optical testing is the key
element in the process. By taking into account the flatness of both the backplane and the front glass
plate, we have assembled LCOS devices. We have reached our aim of less than one quarter wavelength
phase distortion across the active area.
Poster Session
Smart windows with functions of reflective display and indoor temperature-control
I-Hui Lee,
Yu-Ching Chao,
Chih-Cheng Hsu,
et al.
Show abstract
In this paper, a switchable window based on cholestreric liquid crystal (CLC) was demonstrated. Under different
applied voltages, incoming light at visible and infrared wavelengths was modulated, respectively. A mixture of CLC with
a nematic liquid crystal and a chiral dopant selectively reflected infrared light without bias, which effectively reduced the
indoor temperature under sunlight illumination. At this time, transmission at visible range was kept at high and the
windows looked transparent. With increasing the voltage to 15V, CLC changed to focal conic state and can be used as a
reflective display, a privacy window, or a screen for projector. Under a high voltage (30V), homeotropic state was
achieved. At this time, both infrared and visible light can transmit which acted as a normal window, which permitted
infrared spectrum of winter sunlight to enter the room so as to reduce the heating requirement. Such a device can be used
as a switchable window in smart buildings, green houses and windshields.
Super-bright and short-lived photoluminescence of textured Zn2SiO4:Mn2+ phosphor film on quartz glass
Show abstract
Green-emissive textured Zn2SiO4:Mn2+ phosphor film was fabricated by a thermal diffusion of ZnO:Mn on
quartz glass. The characterization has been performed in terms of Mn2+ ions concentration (Mn/Zn=1~9 mol %). As an
increase of Mn2+ ions concentration in the Zn2SiO4:Mn2+ phosphor film, the emission peak was red shifted from 519 nm
to 526 nm, and the decay time to 10% of the maximum intensity was shorter from 20 ms to 0.5 ms. All annealed
Zn2SiO4:Mn2+
phosphor films became textured along some hexagonal directions on the amorphous quartz glass. The
brightest Zn2SiO4:Mn2+
film at optimal Mn2+ concentration of 5 % showed the photoluminescence brightness of 65 %
and the shortened decay time of 4.4 ms in comparison with a commercially Zn2SiO4: Mn2+ powder phosphor screen. The
excellencies can be attributed to a unique textured structure.
A metal-dielectric thin film with broadband absorption
Show abstract
We propose and demonstrate a metal-dielectric thin film that delivers low reflection and high absorption over the entire
visible spectrum. This thin black film consists of SiO2/Cr/SiO2/Al layers deposited on glass substrate. Measured
reflectance and absorptance of the black film are 0.7% and 99.3%, respectively, when averaged over the range 380-780
nm. The total thickness of the black film is only about 220 nm. This thin black film can be used as a thin absorbing layer
for displays that require both broadband anti-reflection and high contrast characteristics.
Multi-domain liquid crystal alignment based on periodical polyimide micro-bars fabricated by inkjet printing
Show abstract
We report a method for the preparation of multi-domain liquid crystal (LC) alignment layers on polyimide (PI) surfaces
using inkjet printed micro-bars. The substrates of PI alignment films with micro-bars are assembled in crossed fashion to
form a two-dimensional lattice to enable a fringe-field-like structure and thus, the multi-domain LC alignment. A LC cell
with twisted nematic (TN) and electrically-controlled birefringence (ECB) domains can be obtained when the cells are
assembled according to the printing directions of the printed PI layers. Electro-optical properties of such cells are
studied. The obtained multi-domain structures can be used to improve the viewing angle of TN displays.