Article

Flat panel display glass: Current status and future

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Abstract

Since the appearance of the Active Matrix Liquid Crystal Display (AM-LCD) in 1995, flat panel display has been the fast growing industry during two decades [1]. Now LCD became the most dominant display technology world-wide. The flat panel display glass also has walked together along with the LCD industry. Great difficulties for manufacturing the flat panel display glass have given high entry barriers for the leading 3 companies: Corning, Asahi and NEG. These 3 companies occupy about 95% share of the flat panel display glass market [2]. However, these days, new players struggle to take significant part in the market. In this paper the detailed technological difficulties are analyzed. Display industry, however, these days in the turmoil of the big change. Plasma display panel (PDP) has not been displayed in the exhibitions or showcases. LCD is going through the mature stage of the industrial life cycle. Lots of ownership change and M&A have reported in the news. After that OLED and lots of touch application gadget appeared in the market. Even though these new devises also use flat glasses, the required attributes are different from those of LCD. The differentiation is important topic in the display industry. Flexible display is interesting theme in both glass and display field. Even though final product appears as a thin plastic display [3], all the manufacturing process happens on the glass substrates. In spite of the drastic change of the display industry, the glass production shows continuous growth. The need of larger screen does not show the saturation. The popularity of touchable hand held devices could continue in near future [4]. However all these situations are not the gospel for the glass industry. The display companies in the red ocean, push down the price of the glass with tremendous pressure. So in near future flat panel display glass also needs breakthrough for survival.

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... The flat panel displays (FPDs) found in cell phones, televisions, and computers are a crucial part of modern technology [1], where the need for FPDs in multiple applications will likely increase in the future [2]. Thus, market demand will continue to drive innovation in FPD manufacturing, such that they will become slimmer, stronger, cheaper, and have higher resolution. ...
... For example, static discharge, which is affected by factors that include surface cleanliness and particle adhesion, can result in FPD failure and lower device yield [3][4][5][6]. These issues are becoming more important as pixel dimensions decrease [2,7]. Glass surface chemistry is also altered by various treatments on the production line; glass substrates undergo multiple chemical treatments before they are suitable for FPD production [8][9][10][11]. ...
Article
Surface silanols (SiOH) are important moieties on glass surfaces. Here we present a tag-and-count approach for determining surface silanol densities, which consists of tagging surface silanols with Zn via atomic layer deposition (ALD) followed by detection of the zinc by high sensitivity-low energy ion scattering (HS-LEIS). Shards of fused silica were hydroxylated with aqueous hydrofluoric acid (HF) and then heated to 200, 500, 700, or 900 °C. These heat treatments increasingly condense and remove surface silanols. The samples then underwent one ALD cycle with dimethylzinc (DMZ) or diethylzinc (DEZ) followed by water. As expected, fused silica surfaces heated to higher temperatures showed lower Zn coverages. When fused silica surfaces treated at 200 °C were exposed to DMZ for two different times, the same sub-monolayer quantity of Zn was obtained by X-ray photoelectron spectroscopy (XPS). Surface cleaning/preparation immediately before HS-LEIS, including atomic oxygen treatment and annealing, played a critical role in these efforts. Surfaces treated with DMZ generally showed slightly higher Zn signals by LEIS. Using this methodology, a value of 4.59 OH/nm² was found for fully hydroxylated fused silica. Both this result and those obtained at 500, 700, and 900 °C are in very good agreement with literature values.
... Figure 4 shows XRD spectra of the amorphous phase in the sample of the LCD screen. No specific diffraction peaks were exhibited, which is typical for LCD glass containing mainly amorphous silicon [49], minor additives of indium, tin [50], and other elements, as presented in Table 7. Figure 4 shows XRD spectra of the amorphous phase in the sample of the LCD screen. No specific diffraction peaks were exhibited, which is typical for LCD glass containing mainly amorphous silicon [49], minor additives of indium, tin [50], and other elements, as presented in Table 7. ...
... No specific diffraction peaks were exhibited, which is typical for LCD glass containing mainly amorphous silicon [49], minor additives of indium, tin [50], and other elements, as presented in Table 7. Figure 4 shows XRD spectra of the amorphous phase in the sample of the LCD screen. No specific diffraction peaks were exhibited, which is typical for LCD glass containing mainly amorphous silicon [49], minor additives of indium, tin [50], and other elements, as presented in Table 7. ...
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The article draws attention to the problem of the presence of metals: germanium (Ge), tellurium (Te), thallium (Tl), and others (Cd, Ba, Co, Mn, Cr, Cu, Ni, Pb, Sr, and Zn) in selected waste of electrical and electronic equipment (WEEE). As a result of the growing demand for new technologies, the global consumption of TECs has also been increasing. Thus, the amount of metals in circulation, of which the impacts on the environment have not yet been fully understood, is constantly increasing. Due to the low content of these metals in WEEE, they are usually ignored during e-waste analyses. The main aim of this study was to determine the distribution of Ge, Te, and Tl (and other elements) in ground sieve fractions (1.0, 0.5, 0.2, and 0.1 mm) of selected electronic components (solar lamps, solar cell, LED TV screens, LCD screens, photoresistors, photodiodes, phototransistors) and to determine the possible tendency of the concentrations of these metals in fractions. This problem is particularly important because WEEE recycling processes (crushing, grinding, and even collection and transport operations) can lead to dispersion and migration of TCE pollutants into the environment. The quantitative composition of e-waste was identified and confirmed by ICP-MS, ICP-OES and SEM-EDS, and XRD analyses. It was found that Ge, Te, and Tl are concentrated in the finest fractions of ground e-waste, together with Cd and Cr, which may favor the migration of these pollutants in the form of dust during storage and processing of e-waste.
... The maximum sizes of FPDs continue to increase while their minimum pixel sizes decrease [4]. As these critical pixel dimensions become more demanding, surface-mediated processes and contamination have an increasingly important influence on FPD device yield. ...
... In particular, the composition and chemistry of display glass surfaces influence material attributes that include surface adhesion, particle contamination, wetting, static charge buildup, and reactivity [5][6][7][8]. Of these, particulate adhesion and electrostatic discharge have become important modes of FPD device failure during manufacturing [4,5]. However, to fundamentally understand these processes and their influence on FPD fabrication, it is necessary to know the surface compositions of glass substrates at a variety of depth scales. ...
Article
Flat panels displays (FPDs) are commonly manufactured on highly-engineered glass substrates known as display glasses. As FPD pixel sizes decrease and pixel densities increase, the surface composition and surface properties of these glasses have an increasingly important impact on device yield, influencing static electricity buildup and discharge, particulate adhesion, rate of contamination, and device lifetime. Here, we apply low energy ion scattering (LEIS) to the analysis of Eagle XG®, a widely used display glass. Surfaces were treated with production-line relevant chemistries including acids, bases, etchants, industrial detergents, and plasmas. The resulting surfaces were compared to as-formed melt surfaces, fracture surfaces, and fibers formed from remelted Eagle XG®. LEIS revealed the elemental composition of the outermost atomic layer of these materials, detecting all major Eagle XG® constituents except boron. The surface composition of the glass differed as a function of forming process used to fabricate it as well as surface treatment. The surface concentration of aluminum on the as-formed melt surface differs significantly from the bulk composition. HCl treatment depleted the surface of all species except silica. HF treatment depleted modifier species from the glass surface to a lesser extent. An alkaline industrial detergent produced an increase in alumina relative to the as-formed glass surface. Treatment with an atmospheric-pressure plasma had no detectable impact on the elemental surface composition of the glass. Aluminum and silicon generally give overlapping signals in LEIS, and these signals could only be resolved here through a combination of optimized experimental conditions and data fitting. Various approaches to this data analysis were explored, including a guided least-squares approach herein referred to as informed sample model approach (ISMA), wherein the pure spectral components required for the fit were mathematically derived from the sample spectra. Most commercial display glasses contain both Al and Si, but there is little discussion of the deconvolution of these LEIS signals in the technical literature.
... The glass substrate is the base material of LCD flat panel displays, and its thinning process is necessary for the end product being lighter, thinner and smoother [1]. At present, the thinning process mainly adopts polishing machines with chemical mechanical processing. ...
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Autonomous planning robotic contact-rich manipulation has long been a challenging problem. Automatic peeling of glass substrates of LCD flat panel displays is a typical contact-rich manipulation task, which requires extremely high safe handling through the manipulation process. To this end of peeling glass substrates automatically, the system model is established from data and is used for the online planning of the robot motion in this paper. A simulation environment is designed to pretrain the process model with deep learning-based neural network structure to avoid expensive and time-consuming collection of real-time data. Then, an online learning algorithm is introduced to tune the pretrained model according to the real-time data from the peeling process experiments to cover the uncertainties of the real process. Finally, an Online Learning Model Predictive Path Integral (OL-MPPI) algorithm is proposed for the optimal trajectory planning of the robot. The performance of our algorithm was validated through glass substrate peeling tasks of experiments.
... As may be observed, no specific diffraction peaks are exhibited, indicating an amorphous material. This result may be expected, since the main component of the LCD screens is silicon [28], combined with small amounts of different metallic oxides, such as indium, REE and tin (not detectable by XRD due to the detection limit of the diffractometer). ...
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Rare earth elements (REE) are essential for the production of technological devices. However, their high demand and low availability, together with an increase in electronic waste generation, compel the development of efficient, economic and green methods for recovering these elements from electronic waste. In this work, a facile method for selective recovering of REE from Liquid Crystal Display (LCD) screen wastes, employing ultrasound assisted leaching is presented. The screen wastes were milled and sieved to pass through a − 325 mesh sieve (44 μm). The milled powder was subjected to ultrasound-assisted leaching in an aqueous medium, at room temperature (25 °C) and pH 6 for 60 min. Subsequently, a magnetic separation was applied to the leach residue. Inductively coupled plasma was employed to quantitatively analyze the composition of the LCD powders and determine the effectiveness of the extraction process. Scanning Electron Microscopy/Energy Dispersive X-Ray Spectroscopy allowed qualitative chemical analysis of the solid materials. The results show that the LCD screen wastes are formed, mainly, by amorphous oxides of Si, Fe, In, Sn and REE. The amount of Gadolinium (Gd) and Praseodymium (Pr) in the wastes were 93 and 24 mg kg− 1, respectively, which justifies their recovery. X-ray diffraction analysis of the magnetic portion of the leached residue, confirmed the presence of an amorphous phase together with crystalline metallic iron alloy. The magnetic behavior, obtained by Vibration Sample Magnetometry, helped to understand the nature of the residues. The formation of this metallic alloy is attributed to the effect of high power ultrasonic during the leach. It was confirmed that the magnetic residue concentrates and recovers 87 wt% of Gd and 85 wt% of Pr contained in the original material. Therefore, ultrasound-assisted leaching is a selective and facile method for recovering Gd and Pr from waste LCD.
... As may be observed, no speci c diffraction peaks are exhibited, indicating an amorphous material. This result may be expected, since the main component of the LCD screens is silicon [28], combined with small amounts of different metallic oxides, such as indium, REE and tin (not detectable by XRD due to the detection limit of the diffractometer). ...
Full-text available
Preprint
Rare earth elements (REE) are essential for the production of technological devices. However, their high demand and low availability, together with an increase in electronic waste generation, compel the development of efficient, economic and green methods for recovering these elements from electronic waste. In this work, a facile method for selective recovering of REE from Liquid Crystal Display (LCD) screen wastes, employing ultrasound assisted leaching is presented. The screen wastes were milled and sieved to pass through a -325 mesh sieve. The milled powder was subjected to ultrasound-assisted leaching in an aqueous medium, at room temperature (25 °C) and pH 6 for 60 minutes. Subsequently, a magnetic separation was applied to the leach residue. ICP was employed to quantitatively analyze the composition of the LCD powders and determine the effectiveness of the extraction process. SEM-EDS allowed qualitative chemical analysis of the solid materials. The results shown that the LCD screen wastes are formed, mainly, by amorphous oxides of Si, Fe, In, Sn and REE. The amount of Gadolinium (Gd) and Praseodymium (Pr) in the wastes were 93 mg kg ⁻¹ and 24 mg kg ⁻¹ , respectively, which justifies their recovery. X-ray diffraction analysis of the magnetic portion of the leach residue, confirmed the presence of an amorphous phase together with crystalline metallic iron alloy. The magnetic behavior, obtained by Vibration Sample Magnetometry, helped to understand the nature of the residues. The formation of this metallic alloy is attributed to the effect of high power ultrasonic during the leach. It was confirmed that the magnetic residues concentrates and recovers 87 wt. % of Gd and 85 wt. % of Pr contained in the original material. Therefore, ultrasound-assisted leaching is a selective and facile method for recovering Gd and Pr from waste LCD.
... As may be observed, no specific diffraction peaks are exhibited, indicating an amorphous material. This result is expected, since the main component of the LCD screens is silicon [28], combined with small amounts of different metallic oxides, such as indium, REE and tin (not detectable by XRD due to the detection limit of the diffractometer). ...
Full-text available
Preprint
Rare earth elements (REE) are essential for the production of technological devices. However, their high demand and low availability, together with an increase in electronic waste generation, compel the development of efficient, economic and green methods for recovering these elements from electronic waste. In this work, a facile method for selective recovering of REE from Liquid Crystal Display (LCD) screen wastes, employing ultrasound assisted leaching is presented. The screen wastes were milled and sieved to pass through − 325 mesh sieve. The milled powder was summited to ultrasound-assisted leaching in aqueous medium, at room temperature (25 °C) and pH 6 for 60 minutes. Subsequently, a magnetic separation was applied into the leach residue. ICP was employed to quantitatively analyze the composition of the LCD powders and the effectiveness of the extraction process. SEM-EDS allowed qualitatively analyzing the chemical composition of the solid materials. The results shown that the LCD screen wastes are formed, mainly, by amorphous oxides of Si, Fe, In, Sn and REE. The amount of Gd and Pr in the wastes were 93 mg/kg and 24 mg/kg, respectively; It represents enough reason to recover it. X-ray diffraction analysis of the magnetic portion of the leaching residue, confirmed the presence of an amorphous phase together with crystalline metallic iron alloy. The magnetic behavior, obtained by Vibration Sample Magnetometry, helped to understand the nature of the residues. The formation of this metallic alloy is attributed to the effect of high power ultrasonic during the leaching. It was confirmed that the magnetic residues concentrates and recovers 87 wt. % of Gd and 85 wt. % of Pr of the total content of these REE in the magnetic residue. Therefore, ultrasound-assisted leaching is a selective and facile method for recovering Gd and Pr from a screen wastes.
... Choi ve ark., düz ekran camlarının mevcut durumu ve geleceği hakkında bilgilendirmelerde bulunmuşlar [127], Patil ve ark., bir cam altlık yüzeyine kaplanmış iletken indiyum kalay oksit ince film üzerinde büyüyen saf brokit TiO 2 nano-iğneciklerin elektro-kromik davranışını raporlamışlar [128], Connelly ve ark., binalarda yeni bir yaklaşım olan, elektrik üreten akıllı cam yada panellerin yüzeyindeki yansıtıcı termo-tropik tabakayı sentezleyip, ışık geçirgenliği ve yansıtma özelliklerini detaylıca irdelemişler [129], Ferraris ve Perero, çeşitli uygulama alanlarında kullanıma aday malzemeler olarak saçınım yöntemiyle elde edilen akıllı, inorganik kompozit kaplamalar hakkında geniş bilgi sunmuşlar [130], Karmakar, tersinir, foto-kromik ve radyo-fotolüminesans cam nanokompozitlerinin kimyasal bileşimleri, hazırlanışları, özellikleri, işlevleri ve uygulama alanlarını anlatan bir kitap bölümü yazmış [131], Swain ve ark., hidro-metalurji metodunu kullanarak sıvıkristal-ekran cam atıklarının HCl ile işlemi sonucu çözünen indiyumu kazanma çalışmalarını kaleme almışlar [132], Cüce, binalardaki enerji tüketimini azaltmak üzere yakın zamanda geliştirilen çok-işlevli izolasyon güneş camında yaşanan en son gelişmeleri ve geleceğe dair yaklaşımları bir makale halinde sunmuş [133], Zhang ve ark., akıllı, enerji-etkin pencere uygulamalarında değerlendirilmek üzere, direkt akım (DC)-reaktif, magnetron saçınım metoduyla soda-kireç-silika cam altlıklar üzerinde 200 o C'de 160 voltla VO 2 ince film tabakasını oluşturup karakterize etmişlerdir [134]. Geleneksel camlarla karşılaştırıldıklarında yeni yüksek teknoloji akıllı camlar binalardaki ısıtma ve soğutma maliyetlerinin düşürülmesinde önemli bir etkiye sahiptirler. ...
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... PbO-TeO 2 and BaO-TeO 2 glasses are of special interest due to their positive, negative and zero-stress optical coefficients [9,10]. Zero stress-optic glasses find applications in advanced optical devices and in flat panel displays where light transmittance should have minimum (ideally zero) variation with stress or in other words even small amounts of birefringence is an undesirable effect [12][13][14]. ...
Article
The atomic parameters of metal ion-oxygen speciation such as bond-lengths and nearest neighbor distances for Ba-O, Te-O and O-O pairs, co-ordination numbers and bond angle distributions for O-Ba-O, O-Te-O and O-O-O linkages are determined by neutron diffraction and Reverse Monte Carlo simulations on the series of xBaO-(100-x)TeO2 glasses containing 10, 15 and 20 mol% BaO. The glass network depolymerizes and the average Te-O co-ordination number decreases from 3.60 ±0.02 to 3.48 ±0.02 with increase in BaO concentration. Te-O bond lengths are in the range: 1.97 ±0.01-1.92 ±0.01 Å. Ba²⁺ is mostly in octahedral coordination and the Ba-O bond lengths are in the range: 2.73 ±0.01 to 2.76 ±0.03 Å. Te-O co-ordination number is also determined by Raman spectroscopy and it shows good agreement with the neutron data. The short-range structural properties i.e. metal ion coordination number (Nc) and bond lengths (d) were correlated with the stress-optic response. The bonding characteristic, Br values were determined from the structural data of xBaO-(100-x)TeO2 glasses and were used to predict the stress-induced birefringence properties.
... Liquid crystals (LCs) have dominated the display industry for over 50 years and are of standard use in small everyday devices [1][2][3]. Typically, such technology comprises a nematic LC confined between two flat plates, as in monitors [4,5], or encapsulated to cavities dispersed in a polymer matrix (PDLC), as in privacy windows [6][7][8]. These rely on the fact that LCs are fluid flexible media extremely sensitive to the confining surfaces and to applied external perturbations. ...
Article
The confinement of liquid crystals inside curved geometries leads to exotic structures, with applications ranging from biosensors to optical switches and privacy windows. Here we study how curvature affects the alignment of a cholesteric liquid crystal. We model the system on the mesoscale using the Landau-de Gennes model. Our study was performed in three stages, analyzing different curved geometries from cylindrical walls and pores, to toroidal domains, in order to isolate the curvature effects. Our results show that the stresses introduced by the curvature influence the orientation of the liquid crystal molecules, and cause distortions in the natural periodicity of the cholesteric that depend on the radius of curvature, on the pitch, and on the dimensions of the system. In particular, the cholesteric layers of toroidal droplets exhibit a symmetry breaking not seen in cylindrical pores and that is driven by the additional curvature.
... Moreover, the growth temperatures of the CVD processes are very high, usually above 800-1000°C [43]. These limit the substrate choice only to quartz glass [44], which can tolerate such high temperature for the CNT direct growth method for display application. ...
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Mechanical properties of glasses can be significantly increased by inducing surface crystallization of a low coefficient of thermal expansion phase. In this work, we produced surface crystallized lithia-alumina-silica glass-ceramics with different crystallized layer thicknesses and analysed the resulting residual stresses and their effect on mechanical properties. The residual stress magnitude was estimated by analytical and experimental methods, as well as numerical modelling. The surface compressive stress reached 390 MPa and 490 MPa, as given by the analytical and experimental determination, respectively. These stresses prevented radial cracking in microhardness and scratch tests. The best glass-ceramic achieved a Vickers hardness of 7.5 GPa and fracture strength of 680 ± 50 MPa in a ball-on-three-ball test. These glass-ceramics are translucent, providing 50-60% transmittance over the visible wavelength spectrum (1.3 mm-thick-sample). This study unveiled the causes of improved mechanical properties and validates the concept that surface crystallization is a valuable technique for developing high strength glass-ceramics.
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Preprint
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