Reflectionless terahertz material with high refractive index
Prof. Suzuki’s group at Tokyo University of Agriculture and Technology, Japan, has created a reflectionless material with a high refractive index in the terahertz region. This was achieved by printing 80,036 pairs of 5.3 microns x 8.9 microns metal wire directly on both sides of thin polymer film in a few hours using silver paste ink with SIJ technology. The measured refractive index at 3THz was 5.88, while the reflectance was as low as 1.3%. The artificial flat material can be applied to components for wireless communications and imaging. The achievement was published in Optics Express (doi: 10.1364/OE.420827) on April 28, 2021.
Photoinitiated Marangoni flow morphing
Prof. Seki’s group at Nagoya University, Japan, has developed a new method for creating micro-grooves onto a polymer surface using SIJ technology. In this method, patterns were printed on a polymer using a special ink by SIJ. After UV irradiation, grooves with about 100µm in width appeared on the pattered parts by Marangoni effect which caused spontaneous mass migration in the polymer surface. This printing-aided photoprocess for surface inscription is expected to provide a new platform of polymer microfabrication. The result was published in Scientific Reports (doi: 10.1038/s41598-019-38709-1) on February 22, 2019.
Alignment-free integration of apertures and nontransparent hulls into 3D-printed micro-optics
Prof. Herkommer’s group at Institute for Applied Optics (ITO) and Research Center SCoPE, University of Stuttgart, has demonstrated micro-optical systems with increased functionality by dispensing opaque ink. The result was published in Optics Letters (doi:10.1364/OL.43.005283) issued on November 1, 2018.
The 3D-printed micro-optical systems are inherently transparent, which causes a degradation of the image contrast due to stray light and scattering. Furthermore, apertures cannot be directly integrated during 3D printing. The team m SIJ printer for dispensing silver ink to fabricate nontransparent hulls and apertures in micro-optics components. As a result, considerable image contrast improvement and a telecentric system with a single lens were achieved. This approach paves the way for the realization of a variety of micro-optical systems. It is moreover a potential approach for the fabrication of smooth silver films as reflective surfaces.
Inkjet-Printed Nanocavities on a Photonic Crystal Template
By F.S.F. Brossard, V. Pecunia, A.J. Ramsay, J.P. Griffiths, M. Hugues, H. Sirringhaus Cavendish Laboratory (UK), University of Cambridge, (UK), Soochow University (P.R. China), University of Sheffield (UK), Universite Cote d’Azur (France) Advanced Materials 1704425 (2017)
The authors have demonstrated femtoliter inkjet printing on a 2D PhC template, and the creation of reproducible and structurally tunable high-Q-nanophotonic cavities by drawing lines, dots and crossed strips. A particular attractive feature of this bottom-up fabrication approach is the ability to fine-tune to the sub-10 nm level the thickness of the material deposited on the PhC by controlling the number of printer passes. The coupling strength of PhC photonic molecules was also shown to be controlled simply by changing the separation of the printed strip cavities with submicron resolution.
Microarrays of Phospholipid Bilayers Generated by Inkjet Printing
Professor Hiromasa Imanishi , Associate Professor Kenichi Morigaki and Miss.Misato Yamada of the Graduate School of Agricultural Science and Research Center for Environmental Genomics, Kobe University, a group of researchers have succeeded to Microarrays of Phospholipid Bilayers Generated by Inkjet Printing.
We report an efficient and reproducible method to generate a microarray of model biological membranes on a solid substrate by applying the inkjet printing technology. Although inkjet printing is currently widely used for industrial fabrication processes, including biological materials, printing lipid membranes remains technically challenging due to the hydrophobic nature of droplets and instability of the lipid bilayer structure against dehydration. In the present study, we printed lipids onto a glass substrate covered with a micropatterned membrane of a polymeric phospholipid bilayer. Polymeric bilayers were formed by the lithographic photopolymerization of a diacetylene-containing phospholipid, 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DiynePC). After removal of nonpolymerized DiynePC with a detergent solution, natural lipid membranes were incorporated into the polymer-free regions (corrals) by using an electric-fieldbased inkjet printing device that can eject subfemtoliter volume droplets. To avoid rapid dehydration and destabilization, we preprinted an aqueous solution containing agarose and trehalose onto the corrals and subsequently printed lipid suspensions (“two-step-printing method”). After rinsing, stable lipid bilayer membranes were formed in the corrals. The bilayers were continuous and fluid as confirmed by fluorescence recovery after photobleaching. We could introduce multiple bilayer patches having different lipid compositions into the neighboring corrals. The present results demonstrate that the combination of a patterned polymeric bilayer and inkjet printing technology enables efficient, reliable, and scalable generation of the model membrane microarrays having varied compositions.
Inkjet printing for high-performance organic semiconductor devices
Under the leadership of SIJ Technology, Inc., a venture business engaged in research and development of super-fine inkjet technology based on research results from the National Institute of Advanced Industrial Science and Technology, Professor Junichi TAKEYA and Associate Professor Toshihiro OKAMOTO of the Institute of Scientific and Industrial Research, Osaka University, a group of researchers have succeeded developing a super inkjet (SIJ) printer whose fine patterns are less than 1/10th the size of conventional inkjet patterns by precisely controlling the droplet volume ejected from the inkjet nozzle onto the circuit board. Sizes and orientation of organic semiconductor single crystals can be adjusted by controlling the ink ejection method and direction enabling and enhancing the production of high-quality organic ultra-fine thin-film transistors. Furthermore, as it is possible to place only the amount of ink needed where it is needed with the SIJ printer, the use of expensive organic semiconductor can be significantly reduced, contributing to energy saving and cost reduction. Moreover, as the films made available by this technology are ultra thin and fine, it is thought that even if they are formed on flexible substrate surfaces, they will not break easily and will show high compatibility. This group continues to research materials and make efforts to optimize printing conditions, applying this technology to large organic semiconductor arrays.
＊January 29, 2013
Realization of low-resistance ultra-fine copper lines using inkjet technology
SIJTechnology, Inc., IOX Co., Ltd., NGK Spark Plug Co., Ltd.,Osaka Municipal Technical Research Institute (OMTRI),and the National Institute of Advanced Industrial Science and Technology (AIST) have jointly realized ultra-fine wires with a line width of 5 µm and specific resistivity of 8.1 µΩ•cm through the research commissioned by the New Energy and Industrial Technology Development Organization (NEDO).
The wires were fabricated by direct patterning with an inkjet technology and a technology for reduction under extremely-low oxygen partial pressure. The wires are expected to contribute to the development of next-generation IC boards and micro printed circuit boards for cell phones and IC tags.
Realization of Low-resistance Ultra-fine Copper Wires Using an Inkjet Technology
＊October 28, 2013
– Copper-based inkjet ink was developed by applying a nanoparticle production technology
– Copper wires with a line width of 3 µm were fabricated using an ultra-fine inkjet technology
– A specific resistance7) of 4 µΩ•cm of the wires was attained with a reduction technology under extremely-low oxygen partial pressure
Development of manufacturing process for optical lens mask
Photolithograph process is widely used as a manufacturing process for optical mask of camera, microscope and endoscope.Development of manufacturing process for optical lens mask by using SIJ will bring the merits of the reducing the number of parts and improvements of optical performance. We will provide low cost and high quality optical lens mask compared with that of conventional photolithograph process
Development of ink jet bumping technology for ultra high density
In the early phase of development, we could not make satisfactory bump height by use of gold nanoparticle ink because the ink has low solid content and high fluidity. We mainly focused on developing the printing process, such as a development of volume control and printing procedure, temperature control of substrate and so on. As a results, shape controlled bumps with high density could be achieved.
Ink Jet Technology Realizes 1-Micrometer Channel Length Organic Transistors
The group was led by Takao Someya,a professor at Tokyo University. They have successfully achieved a transconductance of 0.76 S/m for organic thin-film transistors with 4 V operation, which is the largest value reported for organic transistors fabricated using printing methods. Using a Super Inkjet Printer, silver electrodes with a line width of 1 μm and a channel length of 1 μm were printed directly onto an air-stable, high-mobility organic semiconductor that was deposited on a singlemolecule self-assembled monolayer-based gate dielectric. On reducing the droplet volume (0.5 fl) ejected from the inkjet nozzle, which reduces sintering temperatures down to 90 °C, the inkjet printing of silver electrodes was accomplished without damage to the organic semiconductor.