As today’s electronic devices become faster and more fully featured, achieving electromagnetic compatibility (EMC) becomes increasingly challenging. One of the world’s leading computer manufacturers knew this when it asked Schlegel Electronic Materials (SEM) to design shielding for the I/O ports in the company’s new line of personal computers.

SEM was the first company to develop I/O gaskets from a soft, resilient fabric and foam combination that has been used in everything from small D-SUB connectors to large arrays in telecommunications cabinets. In this case, the surface area of the connector array requiring shielding – 7 inches long by 2.5 inches high – was relatively large and included a number of openings. In the past, the computer manufacturer would have employed stamped metal shielding. With today’s increasingly powerful machines, however, stamped metal shields do not provide sufficient shielding integrity. Metal shielding can also have sharp corners that can snag during installation or prove hazardous to installers.

SEM’s flexible, resilient I/O shielding gaskets combine highly conductive metalized fabric around a soft and resilient urethane foam core. With millions of contact points, and a perfect mechanical fit, the conductive gasket makes 100-percent contact with the surface, outperforming such alternative shielding methods as stamped metal, Beryllium copper and other conductive elastomeric shielding products.

Other advantages of SEM I/O shielding gaskets proved to be: Low-cost prototypes compared to those produced by metal stamping Custom die cutting and finishing options Low tooling cost Lightweight and high resiliency facilitated shipping worldwide to subcontractors Fast, easy and safe installation.

Conductive Silver Tape (CST) Reduces EMI in Notebook PC Display Cable

When a leading personal computer manufacturer developed a new line of state-of-the-art notebook computers with high-resolution, and Thin Film Transistor (TFT) screen displays, the company also created a significant electromagnetic interference (EMI) shielding challenge.

The issue: Although recognized for their quality and high resolution, TFT displays emit high levels of EMI. Of particular concern was the interconnect cable that attaches the motherboard to the display. The cable required exceptional shielding and it needed to remain flexible enough to allow the display to open and close regularly.

The solution: Schlegel Electronics Materials (SEM) Electronic Materials’ tough Conductive Silver Tape (CST) meets high-level electromagnetic compatibility (EMC) demands and can withstand the repeated movement of the display and flexing of its associated cabling.
Before turning to SEM Electronic Materials, the manufacturer considered using copper foil tape, but found it inadequate for several reasons: The frequent opening and closing of the computer caused the foil tape to crack and reduced its shielding effectiveness. The resulting reduction in shielding effectiveness could cause non-compliance with EMC regulations. Copper tape presents risks for assemblers who can cut their hands on its sharp edges. With SEM’s flexible, easy-to-use Conductive Silver Tape, the manufacturer resolved these concerns.

Composed of silver-plated fabric and conductive adhesive, SEM CST delivers average attenuation of 60 dB*, which is more than enough to shield the cable in this application. SEM CST also addressed all the manufacturer’s durability and assembly issues. With its pliable, but tough nylon ripstop fabric, SEM CST endured a punishing 100,000-cycle flex test simulating the motion of opening and closing the computer’s display cover. After this formidable test, SEM’s CST showed no signs of cracking or compromise in shielding effectiveness.

For assemblers, the SEM CST’s soft fabric is safe and easy to work with, staying firmly in place with SEM’s strong, high-tack conductive adhesive. The conductive fabric base also allows the tape to be custom-cut in virtually any unique shape with simple, inexpensive tooling – which helps keep costs low for the manufacturer. An off-the-shelf, low-cost solution, SEM CST makes an open-and-shut case in the use of flexible shielding products. For more information, please visit the SEM CST Tape page.

EU Directive on the Restrictions On the use of Hazardous Substances
Materials to be phased out by 01/01/2006:

Lead
Mercury
Cadmium
Hexavalent Chromium
Polybrominated Byphenils
Polybrominated Diphenil Ether
None of the substances listed above are present in or are used in the manufacture of Schlegel Electronics Materials EMI Gaskets.

EU Directive on WEEE
Member States implement Directive into their national legislation by 03/03/2004.

To be removed from any collected WEEE

PCB containing capacitors
Mercury containing components (switches)
Batteries
Printed circuit boards
Toner cartridges, liquid and pasty, colour toner
Plastic containing brominated flame retardants
Asbestos waste
Cathode Ray Tubes
CFC, HCFC, or HFC’s
Gas Discharge
Lamp Liquid crystal displays (Surface > 100 sq. cm.)