The Sumitomo Electric Group, based on its core business of electric wires and cables that stemmed from the former Sumitomo copper business, has developed many unique products of wiring materials, raw materials, and parts and components in response to the needs of electronics market. The Group has continued developing new technologies and products that meet the demands of the times, such as compact, lightweight, environment-friendly, flame retardant, heat-resistant, or high-speed transmission products. The results are evident in various applications from goods familiar to us in our daily life, such as smartphones and tablet PCs, to highly advanced devices such as medical, automotive and aircraft equipment.

Recently, the miniaturization and high functionalization of electronic devices have been progressing increasingly. Therefore, flexible printed circuits (FPC) are also required to be thinner and to realize finer pitch pattern formation. Regarding interlayer connection technology, a key technology for these factors, we have developed a new interlayer connection technology with our original nano-conductive paste, “paste via technology,” an alternative to traditional plating through hole technology (PTH). The newly developed technology allows formation of interlayer connection part with no increase of copper thicknesses associated with PTH, thereby enables production of thinner FPCs with fine pitch formation. Now we have started mass production of these FPCs. This paper describes our novel “paste via technology.”

Due to the increasing demand for high speed communication in electronic equipment, rapid improvement is observed in data transmission rate through interface and wireless communication device. Particularly in the mobile device such as mobile phone and tablet PC, thinner and lighter FPC is required. In such high speed transmission field, flexible printed circuit (FPC) has been applied in place of co-axial cable. From this kind of circumstance we have started the development of high speed FPC. We have verified the transmission performance of the in-house developed FPC supporting USB 3.0 and 4G-antenna by optimizing FPC structure and material, thereby demonstrate the application possibility of the FPC in the high speed transmission field.

Flexible flat cable is widely used for internal wiring in the electronic devices due to the advantage of its flat shape for highdensity wiring compared with the wire harness. Increasing of electronic equipment processing large volume of signals at high speed accelerates the demand for a flat cable that transmits signals in high speed with low loss. Sumitomo Electric Industries, Ltd. has already developed and manufactured flat cables suitable for high-speed data transmission that conforms to the LVDS technology. To meet the market needs for higher transmission performance, the company has succeeded in producing a new flat cable. This cable consists of polyolefin based low dielectric loss adhesive and shows excellent transmission property.

In data centers, direct attach cables with twinax wire have been used to date in order to avoid defects such as skew. However these cables have drawbacks of being thick and hard. In the background of a recent trend of the rack highly dense with switches and servers, which is common in many data centers, there is a growing need for thin and flexible cable that provides better wiring operation and heat dissipation for intra-rack wiring of up to 3 m. Sumitomo Electric Industries, Ltd. developed novel thin and flexible direct attach cables (SFP+ and QSFP+) by using the advanced micro coaxial wire technology cultivated through information appliance products.

"The miniaturization of electronics appliances has been restricted with conventional antennas that are made of magnet wire coils and have poor flexibility. To address this challenge, we replaced magnet wire coils with flexible printed circuits (FPCs) by utilizing our original 3-dimensional wiring technology for the first time in the industry. This improved flexibility of the antennas and enabled size reduction. Our new product enhances the functionality of electronics appliances by offering cordless charging capability or water- and dust-proof properties. Having these advantages, this product is expected to be used in a variety of fields where the equipment need to be smaller and lighter such as wearable devices, health-care and industrial equipment."

One of the advantages of flexible printed circuit (FPC) is that it can keep various shapes due to its highly flexible nature. By using this advantage, the light distribution property can be changed in a light-emitting diode (LED) lighting using LEDs with high directivity. However, the low thermal conductivity of FPC had considerably limited its application to LED lighting. In order to solve this challenge, we developed a high heat diffusion structure that greatly improves FPC’s thermal conductivity and a gluing technique that enables 3-dimensional constitution of FPC. Thereby we made it possible to realize an LED module in which the FPC controls light distribution property with high heat diffusion. This newly developed technique is also applicable to high output LED.

For the realization of a “low-carbon society,” there is an increasing demand for high efficiency power conversion. Gallium Nitride (GaN) is highly anticipated as a semiconductor with high potential for power devices. We developed vertical GaN Schottky barrier diodes on free-standing GaN substrates and demonstrated their high breakdown voltage and low on-resistance. In this paper, we demonstrated the advantage of GaN SBDs in terms of switching characteristics and longtime reliability.

In accord with recent trends of environmental consideration and pursuit for comfortableness of hybrid vehicles have been popular. Simultaneously, higher functionality in vehicles requires increasing number of electrical components. Such vehicles mount sound absorbers in every corner in the vehicle for silence. These hybrid vehicles and luxury vehicles increasingly adopt high performance sound absorbers. On the other hand, as in-vehicle electrical components increase, the number of parts to manage are also increasing at car plants. Thereby, functional integration for reduction of parts is enhanced by modularization. We developed modularization technology with wire harness and sound absorber. The technology realized reduction in both components to manage and work process at plants, and has been adopted at major car manufactures.

We have developed “battery wiring module” for high voltage batteries of hybrid vehicle and started mass production of the modules as our first product group. The product is adopted by Honda Motor Co., Ltd. and mounted to the new model ACCORD/FIT HYBRID. The battery wiring module is a component having a function of connecting high voltage battery cells that are power source for a hybrid vehicle in series, and incorporates terminals and harness to detect the voltage between these cells. Parts equipped with the similar function are required in other eco-friendly vehicles, including electric vehicles and plug-in hybrid electric vehicles. The product further improves workability and versatility for customers in addition to the basic required performance, safety electric connection and insulation between ambient conductive materials. Followings are explanation of its advantages.

To keep up with the exponential growth of demand for internet traffic, large capacity transmission systems applied digital coherent technologies have begun operating recently. The major challenge in such systems is to improve optical signal-tonoise ratio (OSNR). In order to improve the OSNR, optical fibers with low transmission loss and large effective area (Aeff) are in strong demand. This paper reports on a pure-silica-core fiber (PSCF) with the record-low loss of 0.149 dB/km, which is the first fiber having a loss less than 0.150 dB/km at 1550 nm. The development of Z-PLUS Fiber ULL (Aeff = 1 12 μm2) and Z-PLUS Fiber 130 ULL (Aeff = 130 μm2), both of which have an extremely low transmission loss of 0.154 dB/km on average, is also described. Exhibiting the highest fiber figure-of-merit (FOM), they will be suitable for high capacity and long haul submarine transmission systems applied digital coherent technologies.

With a rapid progress in optical fiber network construction all over the world, fusion splicer users are increasing particularly in newly industrializing countries. They require a fusion splicer with easy operation and high maintainability in any operational environments. We have developed a new core alignment fusion splicer “TYPE-71C+.” It reduced by 43% in size and by 34% in weight compared with the current model and improved in performance under more harsh environments. It achieves 20 seconds of total splice and heat cycle time, which is faster by 55% than the current model. Moreover, TYPE-71C+ is the first and only fusion splicer in the industry that features wireless LAN function. We have also developed “SumiCloud” system, which manages fusion splicers via internet.

Digital coherent technology with multilevel modulation formats is an attractive solution to satisfy the rapid increase in optical traffic demand and has already been adopted in ultra-long haul systems. In the next generation, the application area will be expanded to metro systems, and smaller-sized, lower-power optical components are expected in order to realize high port density. We have developed InP-based modulators and linear driver ICs, which have enabled the modulator module size as small as 34.0 × 16.5 × 6.0 mm3. We demonstrated that a 224-Gbit/s DP-16QAM modulator module, including all of an InP-based modulator, four linear driver ICs, and polarization multiplexing micro-optics, has comparable performance to LiNbO3-based modulators.

The authors have successfully developed new compact optical receiver modules with integrated optical De-multiplexer for 40GBASE-ER4 QSFP+ and 100GBASE-LR4 CFP4. These compact optical receiver modules achieved excellent wavelength specification and sensitivity. By applying the basic structure of the compact optical receiver module for 40GBASE-LR4 QSFP+, the newly developed modules are in the same form as the predecessor. The development of compact optical receiver modules are essential for QSFP+ and CFP4, which are compact optical transceivers, to realize 40 Gbit/s and 100 Gbit/s transmission, respectively. This paper describes the design and representative specification of the new modules.

For a 100 Gbit/s optical transceiver that satisfies the demand of high speed transmission, the authors have developed two types of 25 Gbit/s optical transmitter modules so that a user can select a module depending on transceiver architectonics. One of the two modules has an in-house driver IC for Electro-absorption (EA) modulator integrated in a laser chip and the other has no driver IC. These transmitter modules are transmitter optical sub-assembly (TOSA) type devices with flexible printed circuit (FPC) and LC receptacle. The evaluation results showed good modulation characteristics, lower power consumption and long-term reliability. This paper describes the outline of 25 Gbit/s optical transmitter module structure and evaluation results.

We have been developing a metal-oxide-semiconductor field effect transistor (MOSFET) that has a V-groove shaped trench structure. Forming a 4H-SiC {03 ＿ 38 ＿} facet by thermochemical etching followed by thermal oxidation on the channel region of a trench MOSFET, we obtained low on-resistance because of excellent MOS interface characteristics. Furthermore, we introduced an electric field concentration layer with a p+ type buried region into a drift layer in order to raise high breakdown voltage, suppressing gate insulation film breakdown in the trench bottom. Specific on-resistance and breakdown voltage of the trench MOSFET were measured to be 3.5 mΩcm2 (VGS = 18 V, VDS = 1 V) and 1,700 V, respectively. The introduction of the optimized p+ type buried region improved the breakdown voltage of the trench MOSFETs, and no performance degradation in the specific on-resistance and in the switching capability was confirmed. The typical turn-on and turn-off switching time for the resistive load switching characteristic were estimated to be 92 ns and 27 ns, respectively, at a drain voltage of 600 V. We also tested the stability of threshold voltage in the trench MOSFETs.

A silicon carbide (SiC) power module can offer a higher speed switching performance compared to a silicon (Si) power module. The excessive voltage overshooting caused by the fast turn off switching may damage the power module or the application system itself by exceeding its absolute maximum ratings, where the voltage overshooting must be proportional to the current changing rate and the stray inductance in the module. In order to avoid such large overshooting, the reduction of the inductance is necessary. To overcome such problems, we optimized the inductance with a commercially available 3-dimensional electro-magnetic field simulator, and we assembled a SiC MOSFET with the low on-resistance in the module. As a result, we have successfully developed a module suitable for high speed switching in 20 ns.

In the automotive industry, a trend is seen that in line with the acceleration of automakers’ transferring production to developing countries, an increasing number of production lines are unmanned, or operated by a small number of people. For that reason, there are strong demands for cutting tools having long and stable tool life. To satisfy such demands, we have developed Coated SUMIBORON BNC2010/BNC2020. Compared with conventional cutting tools, Coated SUMIBORON BNC2010 has improved in notch-wear resistance and achieves longer tool life, even in high-precision cutting of strict surface roughness criteria. BNC2020 has improved in breakage resistance and peeling resistance of the coating layer and achieves longer and more stable tool life in continuous and interrupted machining. This report describes the advantages and cutting performance of BNC2010/BNC2020.

In recent years, a demand has increased for stainless steel having good recyclability and low environment load. However, due to its property of being difficult to attain stable processing with high efficiency, stainless steel is classified as one of the “difficult-to-cut materials”. In order to resolve problems of stainless steel turning, Sumitomo Electric Hardmetal Corporation has developed new coated carbide grades “AC6030M” applied with new CVD coating technology “Absotech Platinum” and “AC6040M” applied with new PVD coating technology “Absotech Bronze,” along with new chip breaker “EM-type.” Having high wear- and chipping-resistance, AC6030M is a material for general processing. Having excellent fracture resistance, AC6040M is a material for intermittent machining. These new materials and new chip breaker can satisfy customer demands for cost reduction and higher productivity of stainless steel turning.

With the recent increased interest in the environment, there is a growing demand for environmentally friendly vehicles like hybrid electric vehicle (HEV) and plug-in hybrid electric vehicle (PHEV). This product is a soft magnetic composite core used for boost converter of motor drive system in HEV or PHEV. With soft magnetic composite core, we successfully downsized and reduced weight compared with conventional electromagnetic steel sheet core by utilizing characteristics of high magnetic flux density and isotropic magnetic properties. In this development, we satisfied the demand of downsizing and weight reduction by: using pure and fine iron powder which is superior in downsizing, optimizing powder particle size, examining (or re-designing) of the product shape to maximize the characteristics of the soft magnetic composite, and developing surface modification method by laser processing. As a result, we developed the pure iron-based soft magnetic composite core for automotive reactor that had been produced by electromagnetic steel sheet, and achieved 10% of downsizing and weight reduction with the same performance.

Sandponics is a unique cultivation system self-developed in 1970s ahead of the world based on the principle that leads to a sunlight-based modern plant factory using a soil-free and greenhouse facility. Since the start of its development, the system has maintained competitive advantages of the high quality of products. Improved recently, the system now enables simple water supply management, reducing facility cost and further enhancing quality. We cultivated tomatoes, the most marketable vegetable, as a model, and successfully created unconventional tomato fruits characterized by their volume and proper sweetness and receiving a high reputation, “tasty.” Sandponics is expected to be a promising cultivation system that satisfies the demand for high quality vegetables both inside and outside Japan.