纳米材料和纳米技术在印制线路板基材中的应用前景（5）——提高印制线路板基材的力学性能

本文论述了纳米复合材料对印制线路板基材力学性能的影响,由于力学性能的提高,可以优化设计印制线路 板基材的综合性能,为实现印制线路板基材的轻、薄、小提供了技术上的保证。     

对适应无铅化FR-4型覆铜板性能的探讨（上）

电子安装采用无铅焊料,对PCB的基板材料——FR-4型覆铜板,在加工中有哪些工艺上的改变、需要CCL提高哪些性能上的要求等问题,进行了初步的分析、探讨。     

热分析技术在印制电路板性能测试中的应用

欧盟RoHS指令的颁布实施使印刷电路板步入了无铅时代,这对电路板的耐热性能提出了更高的要求。热分析技术是一种分析测试材料的性质与温度关系的技术。本文介绍了热分析技术——差示扫描量热法(DSC)和热机械分析法(TMA)在印刷电路板性能测试中的应用,并比较了它们各自的特点和主要影响因素。     

A study of electrically conductive adhesives as a manufacturing solder alternative

Soldering processes using tin/lead solder are standard interconnection technologies for electronic manufacturing. These processes are currently under threat from the Waste Electrical and Electronic Equipment and the Restriction of Hazardous Substances (RoHS) environmental directives, issued by the European Union in 2000. These directives explain that solder is to be free from lead by 1986, as lead has been recognized by the European Union as an environmentally harmful material. One solder alternative that has been investigated by the electronics industry is the area of electrically conductive adhesives (ECAs). This paper outlines the electrical and mechanical analysis of two isotropic conductive adhesives where the main properties of joint resistance and adhesive strength were examined before and after different environmental treatments. Joint resistance was measured with a four-probe tester and adhesive strength was examined with the use of shear testing. Cross-sectional and scanning electron microscopy analyses were used to determine problems such as oxidation and moisture absorption that may have an affect on the adhesive properties of the connection. An experimental design was carried out to examine the adhesives on a standard production line. Taguchi analysis was used to determine the build parameters required to produce an optimal adhesive joint. The results show that although ECAs can pass a functionality test, the electrical properties of ECAs are inferior to that of solder with ECAs having a high joint resistance. They also exhibit poor mechanical strength when shear or drop tested and illustrate that current visual inspection techniques used to examine solder joints are not applicable to conductive adhesives.     

抑制同步开关噪声的超带宽电磁带隙结构研究

针对抑制印刷电路板中电源平面与接地平面之间的同步开关噪声问题,提出了一种新型的二维电磁带隙结构（BSEBG）。这一新型结构的设计基于在正方形金属贴片的四角刻蚀出折线型缝隙以降低贴片的有效电容,应用折线以增加相邻贴片的有效电感,单元晶格由折线与含有缝隙的正方形金属贴片桥接构成。仿真分析结果表明：相比于同参数的ZbridgedEBG电磁带隙结构,当抑制深度定义为-30dB时,BSEBG结构阻带范围从220MHz到超过20GHz,相对带宽增加了约15％,阻带下限截止频率降低了110MHz。     

印制电路板企业环境管理之探讨

主要从环境管理的三个层次,即思想、机制和技术或手段论述了印制电路板企业的最终必须走节能降耗、清洁生产的道路并实现“环境效益”、“社会效益”和“经济效益”。     

汽车电子PCB用覆铜板的性能提高——特殊性能CCL的发展综述之二

随着PCB在应用市场领域的不断扩大,对所使用的基板材料性能提出了许多特殊的要求。本篇围绕着汽车电子产品用CCL话题,以松下电工公司此类CCL为研究的主要对象,综述它的可靠性确保、提高方面的技术新进展。     

无芯印刷板变压器电感量的分析与计算

变压器是信号与能量转换、电气绝缘的主要器件,本文介绍一种新型变压器"无芯印刷板(PCB)变压器",提出改进PCB变压器的自感与互感的计算方法.实验证明理论计算和测试结果是一致的.     

Design and fabrication of waveguide-based chip-to-chip optical interconnection network on printed circuit boards

A waveguide-based chip-to-chip optical interconnection network on printed circuit board (PCB) was designed and fabricated, and experiments confirmed that the data rate in each channel could reach above 3.125 Gbit/s and the bit error rate (BER) could be up to 1.27×10-18, which would be a good solution to solve the communication bottlenecks between high-speed very large scale integration chips. Besides, the whole design and fabrication of optical interconnection network on printed circuit board has the advantages of high reliable, low cost and ease of manufacture.     

锥形光波导耦合特性研究

基于耦合模理论,数值仿真了两种耦合结构(FW和WF)下的耦合损耗随锥形光波导芯层尺寸的变换规律;进一步分析了两种耦合结构下锥形光波导端面粗糙度对其模式耦合损耗特性的影响,表明不同模式其端面散射损耗不同;实验结果表明,锥形光波导的输入端芯层尺寸、输出端芯层尺寸及光波导长度,对FW结构下的耦合损耗影响较小,对WF结构下的耦合损耗影响较大。     

基于矩量法的印刷电路板的辐射分析

利用结合二级离散复镜像的矩量法,分析印刷电路板上微带线的电磁辐射问题.应用复镜像理论,详细地推导了微带线结构的闭式空域格林函数和计算公式.针对不同长度和不同端接负载的两平行微带线,进行了辐射研究.仿真结果表明,谐振长度的开路耦合线,产生的辐射功率大;端接匹配负载的耦合线,产生的辐射功率小.为此在高频数字电路设计中,必须确保线长不与谐振长度接近,终端均阻抗匹配.     

电子装备数字电路板自动检测仪设计

摘要：针对某电子装备数字电路板设计自动检测仪,采用单片机＋FPGA的技术方案,包括信号发生、信号采集、与上位机的USB通信以及连接被测板的接插件四大模块。对不同测试对象输入输出间的差异具有柔性适应能力,无须手工配线,操作简单。由上位PC机驱动运行,测试过程自动化程度高,可在1min内完成单板故障检测。     

光电印制板的制造和特征

概述了光电印制板(O/EPCB)的制造和特征,它具有三维3D光学互连用的埋入多模步长指数(MM-SI)波导和集成不同平面微镜(IMM)。利用UV平面印刷术在PCB上积层光电路,利用倾斜曝光制造45°输入/输出I/O耦合元件。     

基于Multisim的电子线路分析与仿真

针对传统电子技术课程教学中存在的问题,提出在教学中引入Multisim进行辅助分析。利用Multisim对电子技术课程中的典型电路进行仿真,其各项结果与理论一致,且可以很方便地改变电路元件参数,观察不同条件下电路的工作情况。将虚拟实验和传统教学有机结合起来,能更好地提高学生的学习积极性和探索精神。     

Soft Microreactors for the Deposition of Conductive Metallic Traces on Planar,Embossed, and Curved Surfaces

Advanced manufacturing strategies have enabled large‐scale, economical, and efficient production of electronic components that are an integral part of various consumer products ranging from simple toys to intricate computing systems; however, the circuitry for these components is (by and large) produced via top‐down lithography and is thus limited to planar surfaces. The present work demonstrates the use of reconfigurable soft microreactors for the patterned deposition of conductive copper traces on flat and embossed two‐dimensional (2D) substrates as well as nonplanar substrates made from different commodity plastics. Using localized, flow‐assisted, low‐temperature, electroless copper deposition, conductive metallic traces are fabricated, which, when combined with various off‐the‐shelf electronic components, enabled the production of simple circuits and antennas with unique form factors. This solution‐phase approach to the patterned deposition of functional inorganic materials selectively on different polymeric components will provide relatively simple, inexpensive processing opportunities for the fabrication of 2D/nonplanar devices when compared to complicated manufacturing methods such as laser‐directed structuring. Further, this approach to the patterned metallization of different commodity plastics offers unique design opportunities applicable to the fabrication of planar and nonplanar electronic and interconnect devices, and other free‐form electronics with less structural “bloat” and weight (by directly coating support elements with circuitry).     

对日本在浸渍加工技术与设备方面创新的综述（上）

文章以2004年～2007年上半年发表的半固化片浸渍加工技术与设备的日本专利为研究对象,对此创新内容及思路加以综述。     

SAC105掺Ni焊球对焊接点强度与可靠性的影响

在内存封装领域,球栅阵列封装(BGA)由于具有高密度和低成本的特点而被广泛采用.在实际的使用过程中,由于遭受外界各种形式的机械负载和冲击造成器件失效,为了改善焊点的强度和可靠性,以SAC105(Sn985AgCu0.5)无铅焊球为参照制备出SAC105 Ni005焊球.为了研究两种焊球焊接点的可靠性与强度,采用焊球的快速剪切测试以及BGA器件的剪切测试方法来检测焊点强度,同时采用威布尔分析方法对两种焊球的热循环测试(TCT)结果进行分析.研究表明,SAC105 Ni0.05焊球比SAC 105焊球具有更长的温度循环可靠性预期寿命、更强的焊接点强度以及更低的脆性断裂的概率.     

Study on High-power LED Heat Dissipation Based on Printed Circuit Board

In order to study the role of printed circuit board(PCB)in high-power LED heat dissipation,a simple model of high-power LED lamp was designed.According to this lamp model,some thermal performances such as thermal resistances of four types of PCB and the changes of LED junction temperature were tested under three different working currents.The obtained results indicate that LED junction temperature can not be lowered significantly with the decreasing thermal resistance of PCB.However,PCB with low thermal res...     

电子电路故障诊断与预测技术分析

近年来,电子产品技术在我国的应用越来越广泛。并且随着电子设备的规模在不断的扩大,复杂程度也越来越高,故障诊断问题日渐凸显。本文通过对故障种类的分析,给出了故障诊断的方法。     

基于介质集成悬置槽线的差分至单端功分器北大核心CSCD

设计了一种基于介质集成悬置槽线的宽带差分至单端功分器。采用槽线与微带线耦合的差分过渡结构,实现了差分电路与单端电路的互连。在较宽的工作频率范围内实现了较好的共模噪声抑制。在10.52~15.58 GHz的频率范围内,测得差分端口处的回波损耗优于10 dB。输出端口在10.1~15 GHz的频率范围内保持15 dB以上的隔离度。差分工作模式下,功分器输出的两路信号具有幅值相等、相位相反的特点。所设计的电路基于多层板结构,将槽线及其核心电路悬置于多层板内置的腔体中,具有自封装、低辐射损耗等优势。