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Newsletter "SEI NEWS" 2014

Home > Company Information > SEI WORLD > Back number > Vol.437

[Newsletter "SEI WORLD" Vol.437]


Sumitomo Electric started research on a thin flat cable as a new wiring component for electronic equipment in 1965, commercialized the technology in 1969, and launched sales of Flexible Flat Cable (FFC) “SUMI-CARD™” in 1977. Today the business, including development, production, and sales of related products, has been taken over by one of its subsidiaries, Sumitomo (SEI) Electronic Wire, Inc. (SEIW).

■Product Data

Release date April 1977

What is SUMI-CARD™?

SUMI-CARD™ is a series of flexible flat cables (FFCs) developed for internal wiring to transmit signals and power in electric and electronic equipment, which constantly requires higher performance with further downsizing. The cable is produced by flattening core conductors and shielding these conductors by an insulator, reducing the overall thickness of the cable and achieving integrated wiring at the same time.

The following figure shows the simplified construction of FFCs. Conventional round-shaped core wire is flattened, reducing the overall thickness of the cable and thus downsizing the equipment in which they are used.

Thickness difference between FFC and conventional round cable


Where is SUMI-CARD™ used?

SUMI-CARD™ is used for internal wiring of various electronic products, such as LCD TVs, printers, video game consoles, laptop PCs, as well as automobile devices such as navigation systems, LCD meters, and laser radars.

Its thin, light and flexible construction contributes to the downsizing of electronic equipment. A large variety of products, including conventional SUMI-CARD™, Au-plating SUMI-CARD™, and Shielded SUMI-CARD™, are available to satisfy customers' requirements.

■Interview with engineer in charge
What is the most delicate process in the production of SUMI-CARD™?

Shigeaki Katsumata, SEIW

It is the difficulty to achieve accuracy in micrometer order in the laminating process of multiple core wires into a flat cable. Also, building each cable according to the design of individual customers, especially for those in the electronics industry, is important. Often, we need to adjust the number of conductors and cable length, attach accessories, and add an extra treatment such as a folding process. Coordinating these processes flexibly and punctually into our production is the key.

What features of SUMI-CARD™ are well regarded by customers?

Thin, flexible, and lightweight configuration, easy connection, no mis-wiring, and repairability are the features our customers find most attractive. With these advantages, SUMI-CARD™ is helping our customers add extra value to their final products. In addition to our standard specifications, we offer a wide range of custom-made variations such as connector-less type directly connectible to the substrate and high-transmission type compatible with 4K TVs. I believe that our engineering flexibility is also attractive to our customers.

Tell us about new models of SUMI-CARD™.

We are developing highly functional models and compound models that are independent from our conventional design, and trying to expand our business by responding to new demands. New designs include a branched terminal type and pitch conversion type. The development of an LED-mounting type, which has potential as an illumination and lighting source, is also ongoing. Meanwhile, by flattening coaxial cable, Ultra-Thin Micro Coaxial (“UTMC”) cable was developed to achieve high-speed signal transmission.

2014 Index
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