Robust production and transportation planning in thin film transistor-liquid crystal display (TFT-LCD) industry under demand and price uncertainties

This paper studies the production and transportation control (PTC) problems under demand and price uncertainties in a multi-product, two-echelon, and hybrid thin film transistor-liquid crystal display (TFT-LCD) production chain. The unique characteristics of the TFT-LCD industry, including quality grades and alternative bill-of-materials (BOMs), are considered in this study. The objective is to determine a production and transportation policy that is robust to price and demand uncertainties. This two-echelon PTC problem is formulated as several two-stage robust optimisation models. An iterative procedure is developed to apply and solve these two-stage models in a TFT-LCD production chain. Our simulation study shows that the proposed method can significantly increase profits while reducing transportation and inventory costs. In addition to improving mean and variance of profits, we use several risk measures to verify the robustness of the iterative optimisation procedure.     

The machine layout within a TFT-LCD bay with a multiple-stacker crane in-line stocker

In this paper, we study the machine layout problem in a TFT-LCD (thin-film transistor liquid-crystal display) bay with a multiple-stacker crane in-line stocker. Unlike other material-handling systems, such as automated guided vehicles and conveyors that only have a transportation function, in-line stockers have both transportation and storage functions. They rely on stacker cranes to perform their transportation function. The in-line stocker in a TFT-LCD bay is often divided into zones. Each zone is served by a stacker crane. Due to its multiple-zone in-line stocker, solving a TFT-LCD bay's machine layout requires us to determine not only the positions of the machines, but also the zone division design. The objectives include the minimisation of total flow distance and the workload balance between stacker cranes. We propose a layout procedure that adopts heuristic and mathematical approaches to assist us in accomplishing the aforementioned tasks. An example problem mimicking a real-case problem was solved to illustrate the proposed layout procedure. The layout design found by the proposed layout procedure was validated with computer simulations. It was also compared with layouts obtained by approaches proposed by other researchers. The simulation and comparison results demonstrate the capability of the proposed layout method in producing a feasible and good machine layout in a TFT-LCD bay with a multiple-stacker crane in-line stocker.     

LCD用光学薄膜市场最新发展动态

本文综述了薄膜晶体管液晶显示器(TFT-LCD)面板及其生产所用材料和零组件(尤其是光学薄膜)的国内外生产和市场的最新发展动态。液晶面板的上游原材料成本大约占液晶面板的70—80%,制作液晶面板需要采用各种光学薄膜,如偏光片、彩色滤色片、扩散膜、反射膜、微透镜膜片、棱镜膜、增亮膜等。本文对这些薄膜和生产偏光片的基材TAC膜、PVA膜等的发展动态分别进行叙述和分析。     

Lean-pull strategy in a re-entrant manufacturing environment: a pilot study for TFT-LCD array manufacturing

The increase of a panel's size in thin film transistor – liquid crystal display (TFT-LCD), results in an increase in stock space and increased cost from work-in-process (WIP). This paper proposes a lean-pull strategy, combining buffers with CONWIP (CONstant work-in-process), which results in shared resources to a re-entrant process in TFT-LCD manufacturing. The buffer size and CONWIP levels are the decision variables and are solved by simulation optimisation. The proposed procedure is applied to a factory that manufactures TFT-LCD. The study shows that the proposed lean-pull strategy can reduce the cycle time and achieve a reduction of 34.57% in WIP. The automated material handling systems (AMHS) stocker utilisation can be reduced from 62.13% to 18.49% without additional investment or facilities. Sensitivity analysis indicates the maximum daily throughput will achieve over 10% improvement. The empirical results from this pilot study provide useful managerial insights for the production control of array manufacturing.     

A multi-model approach to determine early manufacturing parameters for small-data-set prediction

Constructing an accurate prediction model from a small training data set is an important but difficult task in the field of forecasting. This is because when the data size is small, the incomplete data may mean that the model produced cannot sufficiently represent the true data structure or cause the model training to be overfitted. To address this issue, this paper presents an approach that combines multiple prediction models to extract data information in multiple facets. In the multi-model approach, a compromise weight method is proposed to determine the relative reliability of each of the prediction model. The methods used include multiple regression, artificial neural network, and support vector machines for regression. A thin-film transistor liquid crystal display manufacturing case study is used to illustrate the details of this research. The empirical results not only show that the proposed multi-model can reduce the manufacturing variation and increase the production yield, but also can propose a robust and reliable parameter interval to the online engineers in the early manufacturing stage.     

一种新型光学快速自动聚焦系统

为满足基于机器视觉的工业检测系统中对自动对焦快速性的要求,提出了一种基于激光技术的新型嵌入式高速对焦系统.该方法利用在同一光路中激光与可见光互不影响的特性和DSP高速图像处理的能力,通过检测特殊设计光学回路反射回来的激光光斑信息,主动控制运动执行机构实现工业检测系统显微镜的快速和稳定对焦.该对焦方法改善了TFT-LCD光学检测系统中基于被动的图像处理和基于主动测距等传统对焦方式精度低和速度慢等缺陷.测试结果表明,该新型对焦系统极大的缩短了对焦的时间,并且提高了对焦系统的控制精度,满足了工业光学检测系统中实际应用的要求.     

一种液晶面板设备故障诊断专家系统

在液晶面板制造设备故障诊断中,传统方法存在效率低、经验分散等缺陷,为此设计了一种基于规则的设备故障诊断专家系统,能够缩短诊断设备故障时间,高效地整合了故障诊断经验资源。产生式规则按照固定的格式,并具有与人的思维相似,直观、自然、容易理解等特点,将其应用到该专家系统中的知识库中,提高了知识库的增长速度和准确度。实际应用表明,该系统可准确判别液晶面板设备故障原因并提供解决方案,将诊断设备故障平均时间降低了35.5%。     

基于ARM芯片的TFT—LCD显示系统设计

介绍一个典型的基于ARM芯片的TFT—LCD显示系统的设计方案,分析了TFT-LCD的控制时序和逻辑要求,给出了系统电路接口图,并分析了设置S3C2410A的LCD控制寄存器参数的思路;最后介绍了S3C2410A控制TFT—LCD以图形方式显示汉字的软件设计方案。经过使用表明,该设计工作可靠,通用性好,具有参考性。     

A new method to measure the high-shear bulk properties of pressure sensitive adhesives used in LCD devices

The wide application of pressure sensitive adhesives (PSAs) in thin film transistor liquid crystal display (TFT-LCD) devices is based on their advantages that PSAs provide sufficient bond strength and also are cleanly removable upon debonding. These two essential requirements are not obtainable without a proper understanding of the substrate as well as the rheological properties of the PSA. Unlike other substrates, the polarizer, the core unit of an LCD device, may exhibit a considerable dimension change with temperature and humidity. This imposes a large residual stress on the PSA layer, which often generates serious defects such as partial delamination. To overcome this problem, an accurate control of the rheological properties is required in the design of the PSA. In this study a new method is devised to measure the rheological behavior of thin film PSAs under high shear deformation. This method provided us with important information regarding the effects of molar mass and the level of crosslinking on the rheological behavior of the PSA. These findings along with the new method should be applicable not only to the LCD industry but also to other fields where an accurate control of PSA rheology is required.     

TFT-LCD基板玻璃的研究与发展

无碱铝硼硅酸盐玻璃因为其优越的理化性能作为TFT-LCD面板理想的基板材料.详细介绍了TFT-LCD基板玻璃组成发展历史和工艺流程,并对TFT-LCD基板玻璃采用狭缝下引法、浮法以及熔融溢流法三种成形技术的特点与应用状况进行分析比较;最后阐述了无碱铝硼硅系统玻璃的研究现状及进展,总结了SiO2-Al2 O3-B2 O3-RO(R=Mg、Ca、Sr、Ba)系统玻璃各组成对结构、性能的影响.