从用户角度看芯片贴装头技术

不管位于哪个地方或采取什么样的商业模式,现代制造商一直特别看重在变动过程中迅速重新配置平台型贴装机的灵活性,以便能够对变动后的产品实现最优的贴装能力。但是,这一工作耗费时间长,要求专业知识,而这些时间和知识本可以更好地投入到生产线其它地方。在理想情况下,应能够在不需重新配置,不会影响精度、良品率或产能的情况下,贴装常用的各种元件。现在,平台型贴装设备上提供的新一代贴装头技术扩展了这些系统的能力,可以提供高速芯片贴装功能,实现理想情况。在既定的SMT生产线模式中,按贴装能力被宽泛地划分成高速芯片贴装机和泛用机…     

贴装

AX贴装平台能随生产要求而调整。与固定长度贴装平台相平行的多贴装头作业，使得制造商可以购置最适合于当前生产要求的机器配置。随着生产要求的变动，制造商口T以购买、租用贴装头，或在贴装机之间更换贴装头，以满足新的生产要求。据称该贴装平台能确保贴装能力符合生产要求，按生产需要维持资金支出。     

A-系列：AX贴装平台

AX贴装平台能随生产要求而调整。与固定长度贴装平台相平行的多贴装头作业，使得制造商可以购置最适合于当前生产要求的机器配置。随着生产要求的变动，制造商可以购买、租用贴装头，或在贴装机之间更换贴装头，以满足新的生产要求。据称该贴装平台能确保贴装能力符合生产要求，按生产需要维持资金支出。     

贴装——A-系列：AX贴装平台

AX贴装平台能随生产要求而调整。与固定长度贴装平台相平行的多贴装头作业，使得制造商可以购置最适合于当前生产要求的机器配置。随着生产要求的变动，制造商可以购买、租用贴装头，或在贴装机之间更换贴装头，以满足新的生产要求。据称该贴装平台能确保贴装能力符合生产要求，按生产需要维持资金支出。     

新型并行贴装技术：贴装精度与速度兼得

长期以来，速度快和正常运行时间长的优势，使并行贴装技术在超大批量制造领域占有一席之地，然而，超大批量制造逐渐不再流行，殖民地此同时，竞争压力促使中等批量至大批量领域的制造商探索降低成本的技术，试图获得与超大批量制造相同的低单位贴装成本。一直以来，业界都认为有可能将并行贴装技术的适用范围拓宽，应用于中等批量至大批量生产。这种愿望的实现，要求一种新型贴装平台，将并行巾装的速度，精度和成本优势推广至大批量，高混合制造市场。     

环球仪器在亚洲推出AdVantisX平台

环球仪器己将最新推出的新一代表面贴装平台AdVantisX引入亚洲地区。环球仪器旗下拥有不同系列的贴装设备，所提供的解决方案既灵活义准确，能帮助客户以最低的成本来应付千变万化的市场。     

环球仪器引领技术革新Nepcon深圳展现高速与灵活新境界

在本次第十二届华南国际电子生产设备暨微电子工业展（Nepcon South China2006）上，环球仪器展出了其在中等批量和大批量生产中占有独特优势的全线解决方案，其主要组成部分是应用了独创的Lightning闪电贴装头技术的Genesis和AdVantisTM平台，解决了以往高速与灵活性不可兼得的问题，30轴Lightning闪电贴装头提供了广泛的元器件处理能力，可以处理01005到30mm^2的元器件，可以全速贴装CSP，WSP，uBGA和Melfs等元器件。同时，贴装头、送料器和对准相机等各种标准化模块平台选项和功能，使组装厂商可以在产品变动时简便地重新配置Genesis和AdVantisTM平台和生产线，重新优化生产线功能和容量，处理特定的元器件类型，将生产能力最大化。     

环球仪器将新一代表面贴装平台AdVantisX引入亚洲

环球仪器将最新推出的新一代表面贴装平台AdVantisX引入亚洲地区。环球仪器旗下拥有不同系列的贴装设备,但性能表现却如出一辙,所提供的解决方案既灵活又准确,能帮助客户以最低的成本来应付千变万化的市场。     

回转头技术在表面贴装设备中的应用

当今的回转头式贴装设备能够以相对低廉的价格 ,提供高速度和准确的贴装 ,以及先进的识别操作。     

A系列贴片平台（安必昂香港有限公司）

A系列贴片平台提供灵活的解决方案，在相同机器占地面积下，实现30，000cph至100，000cph的高混合、大批量SMT贴装，从而获得最佳的单位贴装盈利。     

适用于VBR视频的周期广播方案

现有的周期广播方案中,大多数只支持CBR编码的视频,仅有少数能够很好地支持VBR。该文提出一种可支持VBR视频的周期广播方案v-RFS。在该方案中,首先根据RFS算法计算出信道上可分配的最大分段数和分段的调度方案,接着把视频分割为一系列等时长的分段,再按照分段序号等于子分段个数的策略,进一步把分段分割为一组等大小的子分段,最后将子分段进行复用,在原信道中循环播出。v-RFS方案可保证按时传输分段,且传输速率稳定。仿真结果表明,与RFS,Smooth RFS方案相比,该方案提高了网络带宽利用率,缩小客户端缓存区空间。     

Virtual spotlighted advertising for tennis videos

How to effectively and less-intrusively deliver the advertising message by spatially replacing regions with advertisements in a period of exposure time for sports videos has been known as a challenging problem. The size, placement locations, and the representation of advertisement are the critical factors that have significant impact on both the recognition effectiveness and the perceived intrusiveness. In this paper, we take advertising theory, psychology, and computational aesthetics into account to develop a novel virtual advertising mechanism, called virtual spotlighted advertising (ViSA), for tennis videos. We utilize the extraneous visual acuity of viewers while watching the attractive object, such that they are not much disturbed from the progress of the game, and at the same time, the inserted advertisement can effectively deliver its message across to them. We propose a framework and realize an exemplary system to serve ViSA. The system automatically detects the candidate insertion points in both temporal and spatial domains and estimates the most effective region for visual communication. Then, the harmonically re-colored advertisements with foveation model based non-uniform transparency, are projected onto the court. The evaluation results demonstrate the effectiveness of the proposed ViSA in terms of recall and recognition. Moreover, the induced visual intrusiveness is limited by the proposed innovative representation style.     

Optimal deployment of large wireless sensor networks

A spatially distributed set of sources is creating data that must be delivered to a spatially distributed set of sinks. A network of wireless nodes is responsible for sensing the data at the sources, transporting them over a wireless channel, and delivering them to the sinks. The problem is to find the optimal placement of nodes, so that a minimum number of them is needed. The critical assumption is made that the network is massively dense, i.e., there are so many sources, sinks, and wireless nodes, that it does not make sense to discuss in terms of microscopic parameters, such as their individual placements, but rather in terms of macroscopic parameters, such as their spatial densities. Assuming a particular interference-limited, capacity-achieving physical layer, and specifying that nodes only need to transport the data (and not to sense them at the sources, or deliver them at the sinks once their location is reached), the optimal node placement induces a traffic flow that is identical to the electrostatic field created if the sources and sinks are replaced by a corresponding distribution of positive and negative charges. Assuming a general model for the physical layer, and specifying that nodes must not only transport the data, but also sense them at the sources and deliver them at the sinks, the optimal placement of nodes is given by a scalar nonlinear partial differential equation found by calculus of variations techniques. The proposed formulation and derived equations can help in the design of large wireless sensor networks that are deployed in the most efficient manner, not only avoiding the formation of bottlenecks, but also striking the optimal balance between reducing congestion and having the data packets follow short routes.     

分形在布局中线长估计的研究

布局问题的目标都是与连线长度有关,且考虑时延优化也与线长有关。由于布局阶段并没有完成最终布线,若希望在无几何走线的情况下判断一个布局的好坏,就要有简单且又有一定精度的线网长度估计方法来估算线长。文中介绍了几种常规的线长估计方法,然后提出了一种将分形引入线长估计的新方法。     

Optimizing Electrode Placement Using Finite-Element Models in Radiofrequency Ablation Treatment Planning

Conventional radiofrequency ablation (RFA) planning methods for identifying suitable electrode placements typically use geometric shapes to model ablation outcomes. A method is presented for searching electrode placements that couples finite-element models (FEMs) of RFA together with a novel optimization strategy. The method was designed to reduce the need for model solutions per local search step. The optimization strategy was tested against scenarios requiring single and multiple ablations. In particular, for a scenario requiring multiple ablations, a domain decomposition strategy was described to minimize the complexity of simultaneously searching multiple electrode placements. The effects of nearby vasculature on optimal electrode placement were also studied. Compared with geometric planning approaches, FEMs could potentially deliver electrode placement plans that provide more physically meaningful predictions of therapeutic outcomes.     

Application of X-rays to nanolithography

The development of a successful fabrication process for electron devices with dimensions in the sub-100-nm domain will require a form of a high-resolution and high-volume patterning. In this paper we discuss the extensibility of X-ray lithography to this domain in terms of the resolution of the technique, considering in detail the effect of diffraction and photoelectrons. We show that optimized masks and exposure systems can deliver with relative ease patterning in the 70-50-nm region, while phase-shifting techniques can extend the resolution to sub-40 nm. High volume is provided by the use of the mask. The challenge remains in the fabrication of the IX mask, and in the achievement of the necessary placement accuracy     

Multidisciplinary Placement Optimization of Heat Generating Electronic Components on a Printed Circuit Board in an Enclosure

A multidisciplinary placement optimization methodology for heat generating electronic components on a printed circuit board (PCB) subjected to forced convection in an enclosure is presented. In this methodology, thermal, electrical, and placement criteria involving junction temperature, wiring density, line length for high frequency signals, and critical component location are optimized simultaneously using the genetic algorithm. A board-level thermal performance prediction methodology based on channel flow forced convection boundary conditions is developed. The methodology consists of a combination of artificial neural networks (ANNs) and a superposition method that is able to predict PCB surface and component junction temperatures in a much shorter calculation time than the existing numerical methods. Three ANNs are used for predicting temperature rise at the PCB surface caused by a single heat source at an arbitrary location on the board, while temperature rise due to multiple heat sources is calculated using a superposition method. Compact thermal models are used for the electronic components thermal modeling. Using this optimization methodology, large calculation time reduction is achieved without losing accuracy. To demonstrate its capabilities, the present methodology is applied to a test case involving multiple heat generating component placement optimization on a PCB.     

Individual wire-length prediction with application to timing-driven placement

In this paper, we address the problem of individual wire-length prediction and demonstrate its usefulness in timing-driven placement. Many researchers have observed that different placement algorithms produce different individual wire lengths. We postulate that to obtain accurate results, individual wire-length prediction should be coupled with the placement flow. We embed the wire-length prediction into the clustering step of our fast placer implementation (FPI) framework . The predicted wire lengths act as constraints for the simulated annealing refinement stage, which guides the placement toward a solution fulfilling them. Experimental results show that our prediction process yields accurate results without loss of quality and incurs only a small cost in placement effort. We successfully apply the wire-length prediction technique to timing-driven placement. Our new slack assignment algorithm with predicted wire lengths (p-SLA) gives on average an 8% improvement in timing performance compared with the conventional modified zero-slack algorithm (m-ZSA).     

An efficient macro-cell placement algorithm

A new approximation algorithm is presented for the efficient handling of large macro-cell placement problems. The algorithm combines simulated annealing with new features based on a hierarchical approach and a divide-and-conquer technique. Numerical results show that these features can lead to a considerable increase in efficiency of the placement algorithm without loss of effectiveness.