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The purpose of this paper is to discuss the chemistry of organic compounds with a liquid crystal phase and their application in flat panel electronic displays.

The paper is a review of liquid crystal display (LCD) technology. It provides an introduction to liquid crystals and LCDs, with an emphasis on their historical development, various LCD technologies employed, their electronic interconnection to driver circuitry and failure analysis.

The current world market for LCDs is being driven by flat panel television sales. As well as their use in television sets, they are to be found in aircraft cockpit instrumentation, computer monitors, mobile phones and digital cameras, all of which would not exist in their present form without liquid crystals.

The paper provides an introduction to LCDs for electronic engineers working in this area, who may be unfamiliar with the chemistry of liquid crystals, LCD technology, electronic interconnection and failure analysis.

A new technology for producing light‐control thin films has been developed by physicists at the GM Research Laboratories (GMR). This new class of films — the GMR version of which is known as Varilux — consists of submicron liquid crystal droplets dispersed in a polymer.

This paper aims to study the effect of hydrolysis route of hydroxypropyl cellulose (HPC) on its esterification performance as liquid crystal material. The assessment was carried out from the data of spectra (Fourier-transform infrared analysis [FTIR] and 1H-nuclear magnetic resonance [1H-NMR]), thermal stability as well as optical properties via forming ordered mesophases at lower concentration than HPC.

The HPC was hydrolyzed by hydrochloric acid-methanol at times 9 and 18 h, and the products were esterified by decanoyl chloride. The products of hydrolysis and the esterification were characterized by FTIR, NMR, nonisothermal analysis, thermo-gravimetric analysis (TGA) and polarizing microscope to evaluate the role of degree of substitution of HPC as a result of hydrolysis, on esterification degree, thermal stability and thermal and liquid crystal behavior of the final esterified HPC.

The pretreatment by acid hydrolysis of HPC was successful for synthesizing novel cholesteric hydroxypropyl cellulose ester. The data of FTIR and TGA thermal analysis proved that hydrolysis and esterification of HPC with the decanoyl chain significantly enhanced crystallinity of this cellulose derivative from 0.57 to (1.7–1.9). Moreover, they provided products with superior thermal stability than pure HPC, as noticed from increasing the activation energy of degradation (E_a) from 514.3 to 806.2 kJ/mol. The NMR measurement proved that hydrolysis of HPC for 9 and 18 h decreased the degree of substitution from 3 to 2.1 and 1.3, respectively. Moreover, the esterified HPC showed a promising birefringence texture (chiral nematic) besides decreasing the critical concentration from 30% for HPC to 10% for the esterified unhydrolyzed HPC, while superior decreasing to 1–5% was observed for the esterified hydrolyzed HPC.

There are two stages for preparation of decanoyl ester hydroxypropyl cellulose. At the first stage, HPC was treated by hydrochloric acid-methanol in ratio 1:10 at times 9 and18 h. At the second stage, HPC and hydrolyzed HPC were refluxed with decanoyl chloride (1:6) in presence of nitrogen atmosphere. The final product was precipitated by distilled water.

There are two stages for preparation of decanoyl ester hydroxypropyl cellulose. At the first stage, HPC was treated by hydrochloric acid-methanol in ratio 1:10 at times 9 and18 h. At the second stage, HPC and hydrolyzed HPC were refluxed with decanoyl chloride (1:6) in presence of nitrogen atmosphere. The final product was precipitated by distilled water.

The novelty of this work was focused on enhancing the crystallinity, thermal stability and liquid crystal behavior of esterified HPC, via decreasing the degree of substitution and consequently the type of OH group subjected to esterification. The decanoyl ester formation from the hydrolyzed hydroxypropyl cellulose is able to form ordered mesophases at even low concentration (promising birefringence texture at concentrations 1–5%). It is worthy to notice that the investigated route is able to omit the role of graphene oxide in promoting the liquid crystal behavior of HPC, as it hasn't any effect on critical concentration. This work will promote the use of HPC in technological applications, e.g. high modulus fibers and electronic devices.

The build characteristics of two liquid crystal (LC) reactive monomers were studied using a table‐top stereolithography apparatus (TTSLA). LC materials contain stiff, rod‐like mesogenic segments in their molecules, which can be aligned causing an anisotropy in properties. When cured in the aligned state the anisotropic structure is “locked in” resulting in materials with anisotropic physical and mechanical properties. By varying the alignment of layers, properties such as thermal expansion coefficient can be optimized. High heat distortion (or glass transition) temperatures are possible depending on the monomer chemical structure. Working curves for the LC resins were developed under various conditions. A permanent magnet placed outside the TTSLA vat was used to uniformly align the monomer in the nematic state. Photo‐initiator type and content; alignment of the nematic phase; and operating conditions affected the working curve parameters. Glass transition temperatures of post‐cured parts ranged from 75 to 1488C depending on the resin and processing conditions. Mechanical analysis data revealed a factor of two difference between glassy moduli measured in the molecular alignment versus the transverse alignment directions. Based on these initial studies, more advanced resins with higher glass transitions are being developed at the University of Dayton.

Liquid Crystal Polymer (LCP) materials are considered to be promising substrates for wireless applications because of their excellent properties. The purpose of this paper is to describe now a novel and compact microstrip ultra‐wideband bandpass filter (UWB BPF) with ultra‐fine conductor traces working over 22 to 29 GHz is fabricated on LCP substrates.

Using standard processing technology, such as photolithography, plasma pretreatment, sputter deposition and wet etching, a microstrip UWB BPF is fabricated on LCP substrates. In order to obtain better adhesion between LCP substrate and copper, the oxygen plasma pretreatment of the LCP substrate surface and a thin titanium adhesion layer are introduced before a copper layer is sputter‐deposited onto the substrate.

The measured and the simulated results agree well. The measured insertion loss is about 8 dB in the passband of the bandpass filter, which is a little high compared to the simulated result (∼5 dB). The out of band performance at both the high frequency and low frequency is very good, almost higher than 35 dB.

This paper presents the realization of (UWB BPF) working over 22 to 29 GHz based on an LCP substrate, which demonstrates the feasibility of the application of the LCP substrate in RF wireless systems and also gives some useful information for later research.

This study aims to motivate the application of some low-cost minerals in synthesizing nanoparticles as effective additives on the performance of liquid crystal (LC) hydroxypropyl cellulose (HPC) nanocomposite film, in comparison with carbon nanoallotrope.

Metallic nanoparticles of vanadium oxide, montmorillonite (MMT) and bentonite were synthesized and characterized by different techniques (Transmission electron microscopy [TEM], X-ray diffraction [XRD] and Fourier transform infrared [FTIR]). While the XRD, FTIR, non-isothermal analysis thermogravimetric analysis, mechanical analysis, scanning electron microscope and polarizing microscope were techniques used to evaluate the key role of metallic nanoparticles on the performance of HPC-nanocomposite film.

The formation of nanoparticles was evidenced from TEM. The XRD and FTIR measurements of nanocomposite films revealed that incorporating the mineral nanoparticles led to enhance the HPCs crystallinity from 14% to 45%, without chemical change of HPC structure. It is interesting to note that these minerals provide higher improvement in crystallinity than carbon nanomaterials (28%). Moreover, the MMT provided film with superior thermal stability and mechanical properties than pure HPC and HPC containing carbon nanoparticles, where it increased the E_a from 583.6 kJ/mol to 669.3 kJ/mol, tensile strength from 2.25 MPa to 2.8 MPa, Young’s modulus from 119 MPa to 124 MPa. As well as it had a synergistic effect on the LC formation and the birefringence texture of the nanocomposites (chiral nematic).

Hydroxylpropyl cellulose-nanocomposite films were prepared by dissolving the HPC powder in water to prepare 50% concentration, (free or with incorporating 5% synthesized nanoparticles). To obtain films with uniform thickness, the prepared solutions were evenly spread on a glass plate via an applicator, by adjusting the thickness to 0.2 mm, then air dried.

These minerals provide higher improvement in crystallinity than carbon nanomaterials (28%), moreover, the MMT and bentonite provided films with superior thermal stability than pure HPC and HPC containing carbon nanoparticles. The mineral nanoparticles (especially MMT nanoclays) had a synergistic effect on LC formation and the birefringence texture of the nanocomposites (chiral nematic).

This study presents the route to enhance the utilization of claystone available in El-Fayoum Province as the precursor for nanoparticles and production high performance LC nanocomposites.

This study presents the route for the valorization of low-cost mineral-based nanoparticles in enhancing the properties of HPC-film (crystallinity, thermal stability, mechanical strength), in comparison with carbon-based nanoparticles. Moreover, these nanoparticles provided more ordered mesophases and, consequently, good synergetic effect on LCs formation and the birefringence texture of the HPC-films.

Summarizes the flat panel display (FPD) industry outside of Japan, with a focus on advances in Korea and Taiwan. Discusses the major manufacturers in each country as well as their current status. Concludes with a brief discussion on the future outlook of the FPD market.

Advanced laser micromachining techniques for a TFT‐LCD (thin film transistor‐liquid crystal display) module have been developed to repair various kinds of defects such as shorts, opens, and degraded TFTs. They have also been designed to analyse failures in the TFT‐LCD. The techniques are as follows: (i) The technique of zapping the excess metal: to repair short defects and/or to isolate the TFT being tested from the adjacent TFTs. This uses a pulse Xe or a Q‐switched YAG laser. (ii) Zapping, followed by the metal deposition technique: to repair open defects and/or to form electrical testing electrodes. This uses a Q‐switched YLF and an Ar ion laser. (iii) The technique of micro‐welding two metal lines separated by an insulating layer: to repair open defects. This uses a Q‐switched YAG laser. (iv) A separation technique utilised on a TFT‐LCD panel adhered with epoxy resin. This uses a pulse Excimer laser. (v) A micro‐annealing technique for a degraded TFT: to recover the TFT characteristics. This uses a Q‐switched YAG laser. Through the study described above, the authors have confirmed that these techniques are highly effective for obtaining TFT‐LCD modules without defects. The yield of TFT‐LCD modules may therefore be expected to improve.

The continuing trend towards increasingly compact circuitry places rigorous demands on the thermal management of electronic assemblies. The problem is particularly severe in power circuitry with integrated control. A number of advanced cooling mechanisms and packaging methods are available, but for consumer products the cost of these solutions is prohibitive. Traditionally, thermal management has been achieved by the attachment of large metal heatsinks, but this introduces further manufacturing processes during assembly. It is demonstrated that efficient heatsinking can conveniently be achieved through the substrate, due to both improvements in, and shortening of, the conduction paths. When used as the final level of packaging in a hybrid assembly, coated steel substrates offer an improvement in thermal performance, in comparison with alumina. The optimum thermal performance is, however, provided by polymer coated aluminium substrate materials.