Role of hole injection layer in intermediate connector of tandem organic light-emitting devices

In this work, we demonstrate three kinds of intermediate connectors (ICs) having a general configuration of “LiNH₂-doped 4,7-diphenyl-1,10-phenanthroline (BPhen)/hole injection layer (HIL)/N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4,4′-diamine (NPB)”, in which the HIL is 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN), MoO₃ or MoO₃-doped NPB, respectively. Tandem organic light-emitting devices (OLEDs), vertically stacking two electroluminescence units, are fabricated using these intermediate connectors in between. The results show that, higher power efficiency is achievable in the cases of utilizing HAT-CN and MoO₃-doped NPB as HILs in the intermediate connectors versus MoO₃, whereas higher current efficiency can be obtained in the cases of using MoO₃ and MoO₃-doped NPB versus HAT-CN. We use the current density–voltage and low frequency differential capacitance–voltage measurements and find that the HILs primarily influence the voltage drop and the charge generation capability of intermediate connectors. The correlation between the effectiveness of intermediate connectors and the performances of tandem OLEDs is established, which can shed light on choosing suitable component materials to optimize the intermediate connectors.     

Mechanical behavior and fatigue life estimation on fretting wear for micro-rectangular electrical connector

With the increasing demand to miniaturize electrical connectors and maintaining its high reliability, micro-rectangular electrical connectors are now widely used. Fretting is generally recognized as an essential failure mechanism for an electrical contact. Considerable work has been carried out to understand fretting of connectors and contact metals, by experiments and simulation methods based on a simplified “hemispheric-flat” model. It is difficult to simulate the contact interfaces between a twist pin and a socket for a micro-rectangular electrical connector. Hence, we develop a 3-D finite contact model. In the present investigation, before the fretting process caused by vibration, an additional insertion step was conducted, in order to obtain the initial state of the contact pair at mated contact surfaces when fretting occurs. We validate consistent behavior for the strand component of the twist pin during the insertion and fretting processes in the simulation. A slight stress release was observed during insertion when the bumped part of twist pin was completely inserted into the socket. The performance of the twist pin, including displacement, contact force, contact area and stress state, during the fretting process was periodically changing due to the vibration of the socket.     

Engineering and reliability aspects of connectors in electronic system applications

This paper describes engineering and reliability aspects of connectors in Electronic Systems. While the physical design of connectors is relatively simple, the reliability in the field is complex as their performances are affected by a direct contact with the environment and the pollutants of the atmosphere. This complexity is further increased when lubrication is used to reduce the friction and wear on connector contact sliding surfaces.     

Estimating the reliability of electrical connectors

Some current approaches to estimating the reliability of electrical contacts and connectors are discussed. These approaches center on the statistical analysis of test data and address the active degradation mechanisms, the determination of appropriate environmental tests with corresponding acceleration factors and exposures, the statistical analysis appropriate for the test data, and the establishment of appropriate acceptance criteria. Each of these issues is treated separately. Multiposition connectors and Mil-Hdbk-217 are discussed. The authors deprecate reliability predictions based on generic databases and failure rate models, such as Mil-Hdbk-217, and describe instead what should constitute a reliability qualification program     

Lifetime prediction of electrical connectors under multiple environment stresses of temperature and particulate contamination

Electrical connectors play a significant role in the electronic and communication systems. As they are often exposed in the atmosphere environment, it is extremely easy for them to cause electrical contact failure. It is essential to carry out the reliability modeling and predict the lifetime. In the present work, the accelerated lifetime testing method which is on account of the uniform design method was designed to obtain the degradation data under multiple environmental stresses of temperature and particulate contamination for electrical connectors. Based on the degradation data, the pseudo life can be acquired. Then the reliability model was established by analyzing the pseudo life. Accordingly, the reliability function and reliable lifetime function were set up, and the reliable lifetime of the connectors under the multiple environment stresses of temperature and particulate contamination could be predicted for electrical connectors.     

二同轴接头理论模型特性阻抗的计算

当今高速信号的传输越来越迫切地需要高性能的连接器与之匹配,故用于传输高速差分信号的多内导体同轴接头在民用机载和军用设备上得到广泛应用。基于计算机的数值计算的方法在分析这种结构复杂的连接器方面体现出了优越性。介绍了运用矩量法计算二同轴接头理论模型特性阻抗的基本原理,并将计算结果与HFSS仿真结果作比较,由对比可知此方法准确、快捷,是分析二同轴接头理论模型特性阻抗的一种有效方法。     

射频同轴连接器的失效原因分析及提高其可靠性的方法

本文介绍了射频同轴连接器几种常见的失效模式,分析了失效产生的原因,并提出一些提高其可靠性的方法.     

连接器卡圈结构的改进

主要对卡圈结构的连接器的失效模式和机理进行了分析，并对如何提高卡圈结构的连接器的可靠性提出了多项改进方案。     

Design and performance of high-precision MT-type connector for1.55-μm zero-dispersion-shifted fiber-ribbon cables

We have found that, for dispersion-shifted fiber (DSF) ribbons, the accuracy with which the fiberhole is positioned in the connector ferrule must be less than 0.6 μm to realize a low average insertion loss of about 0.1 dB. By using the high-precision ferrules, we realized MT-type connectors that achieved a very low average insertion loss of 0.11 dB with a maximum of 0.37 dB. These connectors also satisfied mechanical and environmental stability requirements. We have confirmed that our high-precision MT-type connectors can be used for joining DSF ribbon     

Time and frequency domain characteristics of polarization-modedispersion emulators

We investigate both experimentally and theoretically a new technique to realistically emulate polarization-mode dispersion (PMD). We propose and demonstrate a PMD emulator using rotatable connectors between sections of polarization-maintaining fibers that generates an ensemble of high PMD fiber realizations by randomly rotating the connectors. It is shown that: (1) the DGD of this emulator is Maxwellian-distributed over an ensemble of fiber realizations at any fixed optical frequency; and (2) the frequency autocorrelation function of the PMD emulator resembles that in a real fiber when averaged over an ensemble of fiber realizations. A realistic autocorrelation function is required for proper emulation of higher order PMD and indicates the feasibility of using this emulator for wavelength-division-multiplexing (WDM) systems     

Performance comparison of small form factor fiber optic connectors

A comparison of small form factor (SFF) fiber optic connectors is presented for LC, MT-RJ, SC-DC, and VF-45. Multimode jumper cables were tested using industry standard test procedures and bench marked against the industry standard SC Duplex connector. Initial loss data as well as stress testing was performed. Variations were found in the performance of the connectors types and between connectors of the same type from different suppliers. In some cases the connectors out performed the SC Duplex on some tests but no connectors out performed the SC Duplex on all tests with the mechanical stress tests of axial and off-axial pull being the most difficult to exceed. These connectors are rapidly developing and are at different levels of maturity but none of them tested out to be a fully mature replacement for the SC Duplex connector yet     

导通瞬断测试仪的校准方法

导通瞬断测试仪是用来监测连接线束及连接器在振动试验时的瞬间断电时间,从而判定线束的接触可靠性的一种仪器.目前,导通瞬断测试仪的校准并无可依据的国家检定规程或者校准方法,简要地介绍了导通瞬断测试仪的测试原理,并提出了导通瞬断测试仪的一种新的校准方法.通过验证试验,证实该校准方法完全能够满足导通瞬断测试仪的校准要求.     

同轴连接器退化对无源互调影响的建模研究

同轴连接器具有轻微的非线性效应,这种非线性效应会引起无源互调干扰。同轴连接器在使用过程中会逐渐退化,使无源互调干扰加重,影响通信系统的可靠性。文中设计并进行了加速退化试验来制备不同退化程度的同轴连接器,在加速退化试验前后,测试了连接器的无源互调性能,并提出了一个新的多项式模型来描述不同退化程度的连接器的无源互调性能,模型与实验结果吻合良好。为分析同轴连接器退化对其无源互调性能的影响提供了理论依据。     

High-power performance of single-mode fiber-optic connectors

We measured the continuous wave (CW) laser-induced damage threshold of single-mode fiber-optic connectors at 1550 nm. Clean standard physical contact and angled physical contact connectors did not show any evidence of damage for 10 min exposures of 1 W or 3 W. Defective connectors with scratched or undercut endfaces showed identical high-power tolerance as clean connectors without defects. Samples contaminated with carbon black-doped acrylate showed drastic optical failure signatures at approximately 50 mW. Contaminated connectors with expanded mode field diameters ranging from 20 to 62 /spl mu/m showed higher failure thresholds than standard connectors with 10-/spl mu/m spot sizes. We observed that the optical failure threshold power level (P/sub failure/) increased linearly with spot size for the highly contaminated connectors used in this study.     

Investigation of the occurrence of: no-faults-found in electronicequipment

This paper investigates the occurrence of the NFF (no fault found) failure in electronic equipment. The main types of NFF are outlined, and then the results of accessing the Loughborough University reliability database to investigate the root causes of NFF is discussed. The presence of complex components and connectors and the effect of equipment complexity and fraction-usage are examined as causes of NFF. The presence of connectors or complex components on a board and the fraction usage, and the complexity of equipment have little or no effect on the number of NFF events. No relationship was found between equipment usage or equipment complexity and NFF occurrence. The reason for such a high incidence of NFF in electronic equipment has not yet been identified, and further work into this phenomenon is required. Of course factors such as software faults and transient effects, amongst other causes, are likely to be involved     

Experimental and Analytical Studies of the Connector Insertion Phase

Studies of connectors for electric and electronic automotive systems have been and still are being pursued. The electrical connector reliability mainly depends on the connector insertion force. This force is related to the contact force which is imposed by the connector design. A nonintrusive technique for contact force determination by deflection measurement of the contact spring during insertion phase using a laser device has been developed. The following insertion parameters during the insertion stroke can be measured: contact deflection which yields the contact force, insertion force, and contact resistance. Regarding the results for real connectors, an experimental sample of a connector based on a cylindrical pin crossed with a cylindrical spring is proposed in this paper. With this simple setup, an mathematical model was developed and permits analysis of the influence of each parameter (width, spring radius, etc). Based on analysis of the influence of the spring width and of the gap, this study offers the possibility of optimizing the design of such connectors for use in the automotive industry.      

Network Reliability Optimization via the Cross-Entropy Method

Consider a network of unreliable links, each of which comes with a certain price, and reliability. Given a fixed budget, which links should be purchased in order to maximize the system's reliability? We introduce a new approach, based on the cross-entropy method, which can deal effectively with the constraints, and noise introduced when estimating the reliabilities via simulation, in this difficult combinatorial optimization problem. Numerical results demonstrate the effectiveness of the proposed technique     

Organic small-molecule heterointerface for use in transistor-type non-volatile memory

A chargeable layer is an essential element for charge transfer and trapping in a transistor-based non-volatile memory device. Here we demonstrate that a heterointerface layer comprising of two different small molecules can show electrical memory characteristics. The organic heterointerface layer was fabricated with a pentacene and tris(8-hydroxyquinoline) aluminum (Alq3) layers by sequential vapor deposition without breaking the vacuum state. Pentacene was adopted as the active layer on the top, and Alq3 was used as the bottom layer for charge trapping. The bottom-gate top-contact transistor with an organic heterointerface layer showed distinct non-volatile memory behaviors and showed high air stability and reliability. We investigated the energy structure of the pentacene/Alq3 heterointerface layer to reveal the operation mechanism of the non-volatile memory and suggested that the writing/erasing gate bias-dependent energy barrier originating from the difference between the energy levels of the pentacene and Alq3 layers controls the charge transfer at the heterointerface layer. Our approach suggests a simple way to fabricate heterointerface layers for organic non-volatile memory applications with high air stability and reliability.     

Performance of a shape memory alloy coil-shaped clamp for enhancednormal force in pin-and-receptacle electrical connectors

Electrical connectors can experience a significant degradation in performance due to fretting corrosion, which is particularly problematic when the connector undergoes vibration. Fretting corrosion can be reduced or eliminated if the relative motion between the pin and receptacle is reduced or eliminated. One practical means of reducing the relative motion is to increase the normal force between the pin and receptacle. Unfortunately, increasing the normal force has traditionally implied increasing the insertion and removal forces required for mating and separation of the pin and receptacle. In this paper we describe a connector in which the normal force between the pin and receptacle is increased after the connector is mated and decreased before separation. We implement our approach for connectors that are put in service in elevated temperature environments by placing a coiled shape memory alloy (SMA) wire around the receptacle part of a standard pin-and-receptacle connector. We experimentally demonstrate the efficacy of this approach by quantifying the increase in normal force between the pin and receptacle and by showing a substantial increase in connector lifetime in a vibratory environment     

偏振模色散模拟器产生二阶PMD的理论研究

对基于保偏光纤（PMF）级联的偏振模色散模拟器（PMD emulator)产生的二阶PMD进行了数值模拟，结果表明，采用偏振控制器（PC）连接明显优于可旋转连接器（FC）连接，当级联段数N＝8时，PC连接的模拟器产生的二阶PMD与理论曲线基本符合；PMF的长度对PMD模拟器模拟二阶PMD并没有明显影响。