Infineon Presents Enabling Technologies for "Smart Clothing"

Wearable electronics – broad semiconductor manufacturing and interconnection expertise enables robust and reliable chip integration

Munich, 26 April, 2002 – Infineon Technologies today presented prototypes of functional and robust implementations of microelectronic devices that are suitable for everyday use in “smart” textiles and clothing. In first time ever demonstrations, that lay the groundwork for seamless and reliable integration of electronic functionality in clothing, highly-integration chips and sensor technologies with extremely low power consumption are directly sewn or woven into textile fabrics, thus allowing the full integration of electronic applications in clothes. The demonstrations by Infineon Technologies show key enabling technologies that can be converted into visionary, innovative and cost-effective products by textile manufacturers, outfitters and fashion designers.

Working with partners from the textile and clothing industry, researchers at Infineon created prototypes and design samples that exemplify the integration of electronics in textiles. Simply put, this involves the application of chips and very small sensors encapsulated in special “packages” that are affixed to the textile fabrics, while fine conductive materials woven into the fabric provide the necessary electrical connections. The variety of possible applications ranges from personal entertainment and communications, to commercial logistics, healthcare and security. The range of applications is based on Infineon’s equally broad chip portfolio, which lends itself to many different applications of “smart” textiles. These products include, among others, microcontrollers, Bluetooth, GPS and GSM solutions, memory cards, RFID solutions and biometric sensors.

“True to our motto ‘Never stop thinking’, our researchers have been addressing a subject that will be ubiquitous in a couple of years,” said Dr. Sönke Mehrgardt, Chief Technology Officer at Infineon, to underscore the importance of the development project. “The further evolution of our information society will make everyday electronic applications ever more invisible and natural. The enabling technologies we presented today are a major step toward this objective.”

Audio module

As one possible application, Infineon has developed a prototype audio module that is production-ready for the integration in clothes. In addition to ensuring the functionality – for example, as an MP3 player – special attention was paid to a robust and textile-ready design. The components are designed so that the electronics and the interconnections between the textile structures do not interfere with a comfortable wear, allow for easy and convenient use, and allow the clothing to be washed without the need to remove the electronics.

The design concept for the audio module comprises four units: microcontroller/sound processing chip, removable battery/multimedia card (MMC) module, earplug/microphone and flexible sensor keyboard. All of the components are electrically interconnected through fabric strips with embedded conductors. The audio chip can directly be linked to microphones, earplugs, memories, keyboards, displays, sensors, and actuators. Software is used to define the operating mode of the audio module: an MP3 player, speaker-independent voice recognition, text/speech conversion, music synthesizer, and other applications are possible. The module measures only 25 mm x 25 mm x 3 mm (1 inch x 1 inch x 0.12 inch).

The battery and MMC module (weight approx. 50 g/1.6 oz.) contains a lithium-ion polymer battery for several hours of operation and is attached to the clothing by means of a simple connector. The MMC offers a capacity of 64 Mbytes for digital audio data. The module can easily be removed and fed with data from a PC. The MMC can also be used with digital cameras, PDAs or mobile phones.

The flat keyboard is built with metallized films on an electrically conductive fabric strip. The metal films are attached with an adhesive that is commonly used in the clothing industry. A tiny sensor module is connected to the metal films and registers when the pads are “pressed”. The earplug/microphone set is also connected to the audio module through the fabric strip.

A critical aspect for the ability to be used in daily life is the interconnection structure between the textiles and the electronics. A basic problem in this context is the different scale of the structures, these being in the micrometer range for the chips and in the millimeter range for the textiles. Infineon has developed two different methods to address this issue. One possibility is to connect the chip module to the conductive fabric strips in a similar manner as in wirebonding. The other method is the use of a flexible plastic film (similar to a flexible circuit board) with applied connection pads that are cemented or soldered to the textile structure. In both cases, the module and the connection area are hermetically sealed.

With the MP3 implementation, Infineon has demonstrated the functional, production-ready and robust integration of electronics in “smart” textiles. This approach enables various extensions which also include the use of fingerprint sensors or wireless data transceivers.

Thermogenerator

A critical aspect for the convenient integration of electronics in “smart” textiles is very low power consumption, sophisticated power management and an innovative power supply. Given these requirements, Infineon demonstrated the concept of a thermogenerator that uses human body heat to generate electrical power for the electronic components. The final goal of this approach are clothing applications that do not require a battery.

The miniaturized thermogenerator uses the temperature differential between the body surface and the surrounding clothing to generate electrical power. This principle was already used in special applications such as in space technology. New thermoelectric materials, reduced power consumption of the chips and lower production costs are now enabling a larger range of applications.

Infineon developed a new silicon-based thermogenerator chip that outputs an electrical power of several microwatts/cm2. Research by Infineon has shown that under moderate ambient conditions the temperature differential between the clothing and the skin surface is at least 5 °C. Under these conditions, the new thermogenerator chip can supply more than 1.0 microwatts/cm2 and a voltage of 5 V/cm2 under load, which is sufficient to power special medical sensors or microelectronic chips. With an appropriate implementation, “smart” clothing can monitor pulse, heartbeat, or body temperature and transmit the reading wirelessly to a watch where they are displayed. An application with modern hearing aids is also possible, where the relatively high costs for the batteries can be reduced.

Outlook

The prototypes now presented by Infineon exemplify the practical adaptation of microelectronics in modern clothes and accessories. The provision of these enabling technologies opens up a new innovative market for the textile and clothing industry. There is a very wide range of future applications, which will be expanded even more by new chip generations and technologies. With its broad product portfolio and its comprehensive manufacturing expertise, Infineon is perfectly positioned to support e.g. product developments for “smart” clothing with integrated mobile phone, GPS or Bluetooth functionality for communications, positioning and security applications. Additional possible uses range from the integration of entertainment electronics or games in the consumer market to tasks in healthcare and nursing. Material logistics, product identification or protection against piracy are also interesting applications of wearable electronics.

Infineon Technologies AG, Munich, Germany, offers semiconductor and system solutions for applications in the wired and wireless communications markets, for security systems and smartcards, for the automotive and industrial sectors, as well as memory products. With a global presence, Infineon operates in the US from San Jose, CA, in the Asia-Pacific region from Singapore and in Japan from Tokyo. In the fiscal year 2001 (ending September), the company achieved sales of Euro 5.67 billion with about 33,800 employees worldwide. Infineon is listed on the DAX index of the Frankfurt Stock Exchange and on the New York Stock Exchange (ticker symbol: IFX). Further information is available at www.infineon.com