Liquid Crystal Display Glass Substrate Research Articles

Removal of Cd2+, Cu2+, Pb2+, and Ni2+ by sludge produced from liquid crystal display glass substrate

Removal of Cd2+, Cu2+, Pb2+, and Ni2+ by sludge produced from liquid crystal display glass substrate

A theoretical design method for the nozzle pitch of air-flotation system to reduce large liquid crystal display glass substrate\u2019s deformation

The deformation of large glass substrate in air-flotation system affects detection accuracy of inspection instrument. According to the gas lubrication theory, Timoshenko’s thin film theory and the simulation figure of the pressure distribution of the air film flow field, the air load distribution model of the air film is established, and the deformation expression of the large liquid crystal glass substrate in air-flotation system is given. On this basis, a theoretical design method for designing nozzle pitch of orifice throttling air-flotation system was proposed. Combined with examples, the results of theories and simulation are compared. An experiment on the deformation of the glass substrate was carried out on an experimental prototype. The difference between the experimental results and the theoretical results does not exceed 10%.

Direct observation of crack propagation in a liquid crystal display glass substrate during wheel scribing

AbstractIn‐situ observation of crack propagation in an LCD glass substrate was performed during wheel scribing. It was found that a median crack initiated just beneath the wheel and stopped once, and that the crack re‐propagated after passing through the wheel. In this study, the first pop‐in median crack is defined as the first crack, and the re‐grown median crack is defined as the second crack. From in‐situ photoelastic measurements during a static indentation of the wheel, the maximum tensile stress was observed just beneath the wheel. The tensile stress beneath the wheel was also confirmed from FE analysis. It is considered that this tensile stress is the origin of the first crack nucleation. On the other hand, from post‐observation of the cross‐section of a scribing groove after scribing, it was found that the median crack was closed in the plastic zone. It is considered that this closure results from compressive stress in the plastic zone beneath the scribing groove, and that this compressive stress causes the first crack to be arrested.

AMLCD glass mirror constant and crack flaw size in non-crack LCD panels

ABSTRACTPortable models based on the latest liquid crystal displays (LCDs) have been useful in various areas. Many developers have pursued thinner hardware as well as the advanced performance of portable models. Therefore, as the panel glass continuously becomes thinner, the strength characteristics of glass are highlighted as an important issue. In particular, the strength of the LCD glass is mentioned as an important issue. The occurrence of surface scratches on the active-matrix liquid crystal display glass substrates should be minimized to produce portable models with stability; if their crack flaw sizes are kept below a certain level or close to zero, strength-differentiated LCD panel production will be possible. This study confirmed that in LCD panels where the thin-film transistor-color filter (TFT-CF) is assembled, cracks are generated mainly in the TFT glass, and the mirror constant is at a 60.038 MPaċmm0.5 level. In addition, this suggests that the size of the crack flaws that may occur on the glass surfaces during the LCD process should be minimized to produce panels that can withstand a certain impact level through the fracture surface analysis of the glass crack origins.

Decision support in machine vision system for monitoring of TFT-LCD glass substrates manufacturing

This study addresses classification methodology for the automatic inspection of a range of defects on the surface of glass substrates in thin film transistor liquid crystal display glass substrate manufacturing. The proposed methodology consisted of four stages: (1) feature extraction by calculating the wavelet co-occurrence signature from the substrate images, (2) handling of imbalanced dataset using the Synthetic Minority Over-sampling TEchnique (SMOTE), (3) reduction of the feature's dimension by principal component analysis, and (4) finally choosing the best classifier between three different methods: Classification And Regression Tree (CART), Multi-Layer Perceptron (MLP) and Support Vector Machine (SVM). In training the SVM and MLP classifiers, the simulated annealing algorithm was used to obtain the optimal tuning parameters for the classifiers. From the industrial case study, the proposed feature extraction algorithm could remove the defect-irrelevant image features and SMOTE increased the accuracy of all three methods. Furthermore, the optimized SVM and MLP models were more accurate than the CART model whereas a higher accuracy of 89.5% was observed for the proposed SVM model.

Effect of temperature on electrical conductance of inkjet-printed silver nanoparticle ink during continuous wave laser sintering

To determine the effect of temperature on the specific electrical conductance of inkjet-printed ink during continuous wave laser sintering, the temperature of the sintered ink was estimated. The ink, which contained 34wt.% silver nanoparticles with an average size of approximately 50nm, was inkjet-printed onto a liquid crystal display glass substrate. The printed ink was irradiated with a 532nm continuous wave laser for 60s with various laser intensities. During laser irradiation, the in-situ electrical conductance of the sintered ink was measured to estimate the transient thermal conductivity of the ink. The electrical conductance and thermal conductivity of the ink was coupled to obtain the transient temperature by applying the Wiedemann–Franz law to a two-dimensional transient heat conduction equation. The electrical conductance of laser-sintered ink was highly dependent on the sintering temperature of the ink.

An Efficient and Easy Method for Measuring Warpage and Thickness of Large Liquid Crystal Display Glass Substrate Part

An Efficient and Easy Method for Measuring Warpage and Thickness of Large Liquid Crystal Display Glass Substrate Part

Effect of geometrical characteristics of a scribing wheel on the bending strength of LCD glass substrates

Abstract— Scribing followed by a breaking method has often been applied to separate the individual liquid‐crystal‐display (LCD) glass panels from the mother cells. In some special occasions, especially for compact mobile devices, the bending strength of the glass substrates after breakage is the most important concern. In this study, the effect of the geometrical characteristics of the scribing wheel on the bending strength of LCD glass substrates was investigated. A volume‐crack effective coefficient was defined to estimate the effect of different geometrical characteristics of the scribing wheels. It was found that there is a strong correlation between the bending strength and the coefficient before chipping appears as the scribing load is increased. Thus, the coefficient can be used for the assessment of the geometrical effect of scribing wheels on the bending strength of glass substrates.

Effect of geometrical characteristics of a scribing wheel on the bending strength of LCD glass substrates

Scribing followed by a breaking method has often been applied to separate the individual liquid‐crystal‐display (LCD) glass panels from the mother cells. In some special occasions, especially for compact mobile devices, the bending strength of the glass substrates after breakage is the most important concern. In this study, the effect of the geometrical characteristics of the scribing wheel on the bending strength of LCD glass substrates was investigated. A volume‐crack effective coefficient was defined to estimate the effect of different geometrical characteristics of the scribing wheels. It was found that there is a strong correlation between the bending strength and the coefficient before chipping appears as the scribing load is increased. Thus, the coefficient can be used for the assessment of the geometrical effect of scribing wheels on the bending strength of glass substrates.

An independent component analysis-based filter design for defect detection in low-contrast surface images

In this paper, we propose a convolution filtering scheme for detecting small defects in low-contrast uniform surface images and, especially, focus on the applications for backlight panels and glass substrates found in liquid crystal display (LCD) manufacturing. A defect embedded in a low-contrast surface image shows no distinct intensity from its surrounding region, and even worse, the sensed image may present uneven brightness on the surface. All these make the defect detection in low-contrast surface images extremely difficult. In this study, a constrained independent component analysis (ICA) model is proposed to design an optimal filter with the objective that the convolution filter will generate the most representative source intensity of the background surface without noise. The prior constraint incorporated in the ICA model confines the source values of all training image patches of a defect-free image within a small interval of control limits. In the inspection process, the same control parameter used in the constraint is also applied to set up the thresholds that make impulse responses of all pixels in faultless regions within the control limits, and those in defective regions outside the control limits. A stochastic evolutionary computation algorithm, particle swarm optimization (PSO), is applied to solve for the constrained ICA model. Experimental results have shown that the proposed method can effectively detect small defects in low-contrast backlight panels and LCD glass substrate images.

59.4: A Novel Route for Thinning of LCD Glass Substrates

The present work describes methods to reduce the thickness of glass substrate used in a liquid crystal display (LCD). Reduction of the thickness improves a thin and ligh-weight performance of LCDs. For this purpose, a fluoride-base chemical was introduced as an etchant of the LCD glass. The new etchant was tested and evaluated by comparing it with the conventional etchant, hydrofluoric acid. An apparatus was also introduced. In the apparatus, rollers were used to remove the reaction products of the etchant and glass. Operation of a pilot-scale equipment showed that the total thickness variation and surface roughness, Ra, was less than 1.0 μm and 0.01 μm, respectively, when the LCD glass plate of 550×650mm was thinned from 0.8 mm to 0.61 mm. This indicates that the thinning process developed in the present work can be directly applied to make small-sized LCD modules such as PDAs, cellular phones, digital cameras, etc., using the 0.6 mm thick glass without any additional process like polishing. Improvement of yield is expected due to remarkable improvement of thickness uniformity. Modification of the present process is needed for making large-sized LCD modules for notebook computers using the 0.4 mm or thinner glass.

Bulk diffusion measurements to study the effectiveness of barrier layers: II. Exchange of sodium between liquid crystal display glass substrates with different barrier layers

Na-22 tracer diffusion experiments were performed to study the exchange of Na ions between liquid crystal display glass substrates (Corning Code 1737) separated by different types of layers. Different types of layers were generated (i) by RCA cleaning, (ii) by preannealing in wet air, and (iii) by low pressure chemical vapor deposition. A sandwich configuration was used to study the effect of such layers between two glass substrates on the exchange of Na ions between these substrates. The sandwiches were of the type substrate 1 (containing Na-22 tracer)/layer/substrate 2. Diffusion annealing of such sandwiches led to a redistribution of the sodium tracer. This redistribution was analyzed experimentally with regard to the sodium tracer diffusion coefficient in the bulk and the rate of the sodium tracer transfer across the layer. It was found that all three types of layers considered act as barrier layers, i.e., they suppress the exchange of Na ions between glass substrates.

液晶用ガラス基板の洗浄方法

液晶用ガラス基板の洗浄方法