By: John Michael Pierobon
Flexible circuits are electronic circuits mounted on flexible plastic substrates.
Flexible circuits are often used as connectors in numerous applications where flexibility, space savings, or production constraints limit the serviceability of rigid circuit boards or hand wiring. Flexible circuits have the advantages of being light weight, bend during normal use, and fit in very tight spaces.
People use flexible circuits in a myriad of ways which they may not be aware of. Here is a typical day with flexible circuits.
Most people are awoken by the sound of their alarm clock. Before Richard Nixon was president, the sound came from a real clock. Today, the sound comes from a smart phone. Smart phone touch screens lie on top of a flexible circuit board.
Most people take a hot shower to wake up in the morning. Flexible circuits inside water heaters set and maintain the water temperature.
Fixing breakfast is a morning ritual that involves flexible circuits that are found in microwaves, toasters, coffee makers, and refrigerators.
People use their remote control to turn on their television in the morning to get the news and weather. Both the remote control and the television have flexible circuits inside them. Television shows seem to happen like magic, but inside every television studio there are cameras, microphones, editing equipment, all with flexible circuits inside them.
Flexible circuits are used in creating weather forecasts. The National Oceanic and Atmospheric Administration (NOAA), which is the primary provider of weather information, uses instruments to measure temperature, humidity, wind speed, and barometric pressure. All of these instruments have flexible circuits inside them.
A typical newscast will have a story about NASA or about some military mission. NASA is one of the larger users of flexible circuits. They use flexible circuits to control their instruments and to heat and cool equipment such as fuel tanks, engines, electric motors, deployment mechanisms, batteries, etc.
The military use flexible circuits in electronic shielding, instrumentation panels, jet engine controls, laser gyroscopes, night vision systems, radar systems, radio communications, satellites, smart weapons, torpedoes, de-icing, etc.
Most military uses of flexible circuits have been adopted by the automotive industry. Cars today have flexible circuits in them that control rear window defroster, monitor car emissions and engine vibration, control fuel injection, run the anti-lock brake system, play the music, etc. Automotive electronics is possible because of flexible circuits.
Building automation is possible thanks to flexible circuits. Press a button in an elevator, and flexible circuits go into action. Motion sensors are controlled by flexible circuits. Flexible circuits are embedded in systems that control security, lighting, heating, air conditioning, and ventilation in modern buildings.
Stop at a fast food restaurant, and inside, behind the cash register (which also has a flexible circuit board in it), there are machines with flexible circuits that mix the ingredients in the sauces, cook the food to right temperature, keep the food stored at the right temperature, and fill the drinks to the right amount.
Go visit a sick relative in a hospital and the patient is surrounded by flexible circuits. Every instrument that measures something about a patient be it blood pressure, heart rate, temperature, blood glucose, etc., has a flexible circuit in it. X-ray machines, machines that analyze blood and urine, MRI and PET/CT scanning devices, even the tablet computer doctors carry, have flexible circuits in them.
Some patients even have flexible circuits inside them. Pacemakers and cochlear implants have flexible circuits inside them.
Flexible circuits are at the gym. Every device (treadmill, elliptical, etc.) that has electronics to set and monitor distance or speed has a flexible circuit in it. Even the steam in the sauna at the gym is controlled by a device with a flexible circuit in it.
At the end of the day, one may reflect on their busy and productive day: waking up, showering, fixing breakfast, getting the news and weather, driving to work, getting fast food for lunch, visiting a sick relative in the hospital, going to the gym, and not realize that it was not just possible, but easy because flexible circuits are everywhere.