SOLAR CELLS AND PHOTOVOLTAIC ARRAYS
Solar cell and photovoltaic technologies have made signifi- cant advances over the years. There are indications that solar cell efficiency may reach levels of nearly 50%, values only dreamed of in earlier times. Creating compact, high-density energy-generating solutions using solar cells is a task that is well-suited to flexible circuit technology.
The military has looked at rollup solar cell arrays as a light- weight solution for field deployable energy generation, making them a candidate for future commercial use as the world looks for ways to minimize dependence on fossil fuels. NASA is per- haps the technology’s greatest proponent and uses it to supply energy to the International Space Station. The solar arrays in the deployed configuration are nearly the size of a football field and are capable of generating tens of thousands of watts at voltages up to 160
STILL AND VIDEO CAMERAS
Product development engineers in Japan were quick to recognize the capabilities of flexible circuits technology for a wide range of products. One of the early beneficiaries was the camera industry. As more automated functions were integrated into film-based cameras, flexible circuits were employed to provide power for motors, light meters and range finders. With the emergence of digital imaging in the early 1990s and hand- held video cameras shortly thereafter, flexible circuits expand- ed their interconnection role in the technology, increasing both the number of features and the quality and performance of the products.
RADIO FREQUENCY IDENTIFICATION AND SMART CARD CIRCUITS
New applications and significant growth for flexible circuits exist in radio frequency identification (RFID) technology and smart card technology, which are being increasingly employed for inventory control and security access. In some cases, sen- sors capable of detecting humidity, shock/vibration, light, radiation, temperature and atmospheric chemicals (e.g., ethylene, which can artificially accelerate the ripening of fruit in storage) have been mated with active RFID devices to monitor and track products, livestock and even people. Flexible circuits are ideal candidates due to their thinness and amenability to mass production at low cost. The circuits themselves are rather simple, often not much more than a coil with an intercon- nected chip. Coil circuits can power up the device inductively for inquiry and/or receive and transmit data.