Inkjet printing for flexible electronics: Materials,processes and equipments

Inkjet printing, known as digital writing technique, can directly deposit functional materials to form pattern onto substrate. This paper provides an overview of inkjet printing technologies for flexible electronics. Firstly, we highlight materials challenges in implementing flexible devices into practical application, especially for inkjet printing process. Then the micro/nano-patterning technologies of inkjet printing are discussed, including conventional inkjet printing techniques and electrohydrodynamic printing techniques. Thirdly, the related equipments on inkjet printing are shown. Finally, challenges for its future development are also discussed. The main purpose of the work is to condense the basic knowledge and highlight the challenges associated with the burgeoning and exciting field of inkjet printing for flexible electronics.     

An off-normal fibre-like texture in thin films on single-crystal substrates

In the context of materials science, texture describes the statistical distribution of grain orientations. It is an important characteristic of the microstructure of polycrystalline films, determining various electrical, magnetic and mechanical properties. Three types of texture component are usually distinguished in thin films: random texture, when grains have no preferred orientation; fibre texture, for which one crystallographic axis of the film is parallel to the substrate normal, while there is a rotational degree of freedom around the fibre axis; and epitaxial alignment (or in-plane texture) on single-crystal substrates, where an in-plane alignment fixes all three axes of the grain with respect to the substrate. Here we report a fourth type of texture--which we call axiotaxy--identified from complex but symmetrical patterns of lines on diffraction pole figures for thin films formed by solid-state reactions. The texture is characterized by the alignment of planes in the film and substrate that share the same d-spacing. This preferred alignment of planes across the interface manifests itself as a fibre texture lying off-normal to the sample surface, with the fibre axis perpendicular to certain planes in the substrate. This texture forms because it results in an interface, which is periodic in one dimension, preserved independently of interfacial curvature. This new type of preferred orientation may be the dominant type of texture for a wide class of materials and crystal structures.     

微接触印刷法制备新型液晶垂直取向膜

采用微接触印刷法在盖玻片表面制备了微米级沟槽状N′-β′-氨乙基-N-β-氨乙基-γ-氨丙基三甲氧基硅烷薄膜,通过在其表面组装Cu ²⁺制得了液晶垂直取向膜。当有机膦化合物甲基膦酸二甲酯(DMMP)气体通过薄膜表面时,液晶分子发生偏转;当新鲜空气通过时,液晶分子恢复垂直排列,从而实现对DMMP的定性检测。     

动态喷墨液滴两相流模拟

采用数值模拟方法研究了在平坦固体表面润湿时喷墨液滴的产生过程．以确定出发生液滴的关键．在考虑了表面张力和壁粘连的基础上．利用两相流之流体体积方法（VOF）建立了一个计算流体动力学模型采模拟湿平坦的固体表面上液滴过程．结果表明：基于VOF模型能够模拟润湿固体表面上液滴产生的动态,能够反映动态液滴与润湿固体表面间的相互作用和主要特征．这一模拟提高了对流体流动的认识．可以为一个特定的喷墨应用预测优化设计．     

嵌入式喷印机控制系统

 控制系统需要完成数据传输、打印控制、电机精确定位等功能,是整个喷印机系统中最为关键的组成部分,控制系统的优劣直接影响到喷印机喷印的速度、精度和质量。基于嵌入式技术,本文设计了一种喷印机控制系统,采用华恒科技HHARM2410-Integration-R2嵌入式Linux开发板作为控制核心,并利用网络传输打印数据,使喷印机具有喷印速度快,分辨率高,电机运行平稳,电机定位精确、系统运行可靠性等优点。同时,系统利用uClinux的强大的网络功能实现了运行在嵌入式上的小型Web服务器,通过浏览器访问该嵌入式喷印机控制系统上的Web服务器设置和提取运行时的数据,进行设备的维护与管理。本控制系统已经投入实际使用,相对于上一代基于单片机的控制系统,具有稳定性好、故障率低、喷印速度快、单位时间内喷印面积更大等优点。由于采用了振荡频率更高的喷头,系统相对于上一代控制系统还具有更高的分辨率和喷印精度。     

Patterning organic single-crystal transistor arrays

Field-effect transistors made of organic single crystals are ideal for studying the charge transport characteristics of organic semiconductor materials. Their outstanding device performance, relative to that of transistors made of organic thin films, makes them also attractive candidates for electronic applications such as active matrix displays and sensor arrays. These applications require minimal cross-talk between neighbouring devices. In the case of thin film systems, simple patterning of the active semiconductor layer minimizes cross-talk. But when using organic single crystals, the only approach currently available for creating arrays of separate devices is manual selection and placing of individual crystals-a process prohibitive for producing devices at high density and with reasonable throughput. In contrast, inorganic crystals have been grown in extended arrays, and efficient and large-area fabrication of silicon crystalline islands with high mobilities for electronic applications has been reported. Here we describe a method for effectively fabricating large arrays of single crystals of a wide range of organic semiconductor materials directly onto transistor source-drain electrodes. We find that film domains of octadecyltriethoxysilane microcontact-printed onto either clean Si/SiO(2) surfaces or flexible plastic provide control over the nucleation of vapour-grown organic single crystals. This allows us to fabricate large arrays of high-performance organic single-crystal field-effect transistors with mobilities as high as 2.4 cm(2) V(-1) s(-1) and on/off ratios greater than 10(7), and devices on flexible substrates that retain their performance after significant bending. These results suggest that our fabrication approach constitutes a promising step that might ultimately allow us to utilize high-performance organic single-crystal field-effect transistors for large-area electronics applications.     

包装印刷品设计印刷材料的选择

对于包装印刷品,在包装设计中其材料的选择不仅要考虑包装设计定位及档次的高低,而且还要考虑包装印刷品的功能及环境特性(节约资源、保护环境),以及最终的印刷效果;从功能、环境特性、印刷效果3个方面探讨了包装设计中包装印刷品的印刷材料选择问题;包装印刷品印刷材料的选择主要涉及纸张等承印材料和油墨材料。     

包装印刷技术对包装印刷原稿设计的要求

阐述了包装印刷原稿艺术设计与包装印刷复制技术的紧密结合关系，指出了只有从艺术设计与制版印刷要求相结合的角度出发，才能设计出完美的包装印刷原稿，最终得到完美的包装印刷产品。在此基础上，重点从包装印刷工艺技术的特点出发，具体研究了几类主要包装印刷工艺技术对原稿设计的要求。     

Coulomb-blockade transport in single-crystal organic thin-film transistors

Coulomb-blockade transport--whereby the Coulomb interaction between electrons can prohibit their transport around a circuit--occurs in systems in which both the tunnel resistance, Rb between neighbouring sites is large (>h/e2) and the charging energy, E(C) (E(C) = e2/2C, where C is the capacitance of the site), of an excess electron on a site is large compared to kT. (Here e is the charge of an electron, k is Boltzmann's constant, and h is Planck's constant.) The nature of the individual sites--metallic, superconducting, semiconducting or quantum dot--is to first order irrelevant for this phenomenon to be observed. Coulomb blockade has also been observed in two-dimensional arrays of normal-metal tunnel junctions, but the relatively large capacitances of these micrometre-sized metal islands results in a small charging energy, and so the effect can be seen only at extremely low temperatures. Here we demonstrate that organic thin-film transistors based on highly ordered molecular materials can, to first order, also be considered as an array of sites separated by tunnel resistances. And as a result of the sub-nanometre sizes of the sites (the individual molecules), and hence their small capacitances, the charging energy dominates at room temperature. Conductivity measurements as a function of both gate bias and temperature reveal the presence of thermally activated transport, consistent with the conventional model of Coulomb blockade.     

喷墨印刷技术在超高频天线制作中的应用

 研究了喷墨印刷技术在超高频天线制作中的应用,理论上分析了超高频天线的结构、电感值和喷墨膜层厚度,由此引入分析影响墨滴铺展因素的必要性。在此基础上,利用软件模拟的方法来分析,借助软件中的VOF模型数值模拟和分析墨滴速度、墨滴大小对墨滴碰撞铺展过程的影响情况,结果发现只有控制好影响墨滴碰撞铺展的因素才有可能印刷出性能（导电性等）良好的超高频天线。提出了一些墨滴速度、墨滴尺寸的控制标准,如在其他条件一定的情况下,墨滴的速度最好越小,以免发生墨滴的反弹、飞溅等不良的现象;根据具体条件确定合适的墨滴速度大小。这些工作为分析控制墨滴铺展的参数提供了理论依据,并对喷墨印刷技术在超高频天线制作中参数的调节与控制提供了信息。     

墨盒在运动控制实验装置中的新应用

为了解决运动控制实验装置中,只能将半闭环实验结果描绘出来的弊端,研究了一种在装置中通过单片机控制喷墨打印机的墨盒,并借助计算机串口的实时通讯,在介质上将全闭环实验结果真实描绘出来的系统.给出了墨盒喷墨的原理,单片机控制方法和实际应用电路.在X-Y运动控制实验平台上的实验表明,此种方法能够成功地将全闭环动、静态运动轨迹形象、真实地绘制出来,验证了此方案的合理性与有效性.     

印刷企业的质量成本分析

通过对印刷企业的质量成本分析，将质量成本划分为内部损失成本、外部损失成本、检验成本和预防成本4部分，并运用排列图法、因果分析法、价值工程分析法等方法进行分析，确定了质量成本在一定的区域内达到最佳状态，使企业产品质量效益达到最优水平。     

液滴喷射技术在全聚合物薄膜晶体管制备中的应用

研究液滴喷射技术在全聚合物薄膜晶体管制备中的应用,并着重分析电极材料在预成型基底表面的沉积扩散情况。通过数值模拟,分析隔断材料、液滴与隔断间距、液滴碰撞速度3个因素对沉积的影响。结果发现,只有当这3个要素配置合理时,才能保证液滴的正常沉积,从而保证晶体管的质量。例如,当隔断材料采用聚酰亚胺,沟道宽度为5μm,液滴与隔断间距为30μm,液滴碰撞速度为4m/s时,液滴能够正常沉积,晶体管的质量得到保证。本文结果可为TFTs的制作提供一定的参考。     

JSP打印票据的设计

通过对JSP编程中打印功能进行分析的基础上,利用一个具体的票据打印实例来说明如何实现Java打印功能。从JSP实现打印功能的发展、工作模式、设计和实现过程等方面进行了详细的分析,解决了存在的问题。设计中充分利用了jdk1.4提供的完整的"Java打印服务API"功能,挑选了打印中比较难于实现的表格打印作为实例进行分析,在解决jdk1.4以前版本中Java打印功能不足问题的基础上,提供了源程序的实现,以供JSP编程人员借鉴。     

多光谱技术在印刷中的应用

针对现今印刷复制技术与色彩管理技术的主要缺陷,综述了多光谱颜色复制技术的崭新途径,认为多光谱颜色复制技术为高保真印刷和跨媒体出版奠定了基础,并对该技术的基本原理、优越性作了较为全面的阐述,分析了多光谱技术在印刷中的具体应用及其发展趋势。     

号码打印系统的研究

号码识别、号码记录与号码列表打印等相关技术已成为纸币鉴定系统中的重要部分。介绍了基于行式热敏打印机(PO S58)设计的一款号码打印系统,论述了该系统的结构组成,并给出了系统软件设计流程。     

镍基单晶高温合金表面再结晶控制技术的研究进展

针对镍基单晶高温合金构件的表面再结晶控制技术,结合国内外相关工作的研究状况,从单晶高温合金构件表面再结晶的形成机理、再结晶的表面效应、基于再结晶预防的构件设计、单晶构件热成型过程和冷加工过程再结晶控制技术等几方面,对镍基单晶高温合金构件的表面再结晶控制技术领域取得的研究成果进行总结和分析。重点论述了各国单晶再结晶控制技术,提出中国镍基单晶高温合金构件的表面再结晶控制技术存在的差距及未来研究重点。     

2020年3D打印热点回眸

3D打印是基于材料累加原理,将计算机中的三维模型通过分层添加材料打印出实物的一种增材制造技术.2020年,3D打印研究在打印机理、技术改进及应用拓展等方面取得了重要进展.从打印方法改进、新型墨水研发、新型结构制备和应用,以及金属3D打印机理研究等方面回顾了3D打印的年度研究热点和代表性成果.