Sensing in Consumer and Industrial Systems

You have to be fascinated at precise mechanical structures that are much smaller than the width of a human hair. That is exactly what microelectromechanical systems (MEMS) or microsystems technology provides for sensor applications. With their capabilities for achieving good performance, small size and low cost, MEMS is the fastest growing sensing technology. Based on combined forecasts from market research analysts In-Stat, Nexus and Yole Development, STMicroelectronics estimates the MEMS market will grow at around 50 percent over the next five years, heading toward $10 billion by 2010. However, this includes more than just sensors.

From a broader semiconductor technology perspective, IC Insights' 2007 Optoelectronics, Sensors and Discretes (O-S-D) Report (http://rbi.ims.ca/5406-593) shows worldwide sales of solid-state sensors and actuator devices growing 19 percent in 2007 to $6.3 billion after increasing nearly 18 percent in 2006 to $5.3 billion. Again, this includes more than just sensors; it includes actuators, as well. With a 30 percent cumulative average growth rate (CAGR) between 2001 and 2011, by 2011 sensor/actuator sales will grow to $12.7 billion. The report includes two very interesting conclusions.

For one, automotive applications have driven new sensing technologies and were more than 60 percent of the total sensor and actuator applications earlier this decade. The report sees new applications in consumer products, medical devices and security systems reducing the automotive portion to 37 percent by 2011.

The second aspect specifically involves sensors. The report forecasts inertial sensors (accelerometers and gyroscope devices) will become the largest product category in solid-state sensors in 2008, exceeding pressure and magnetic sensor categories.

Application Examples of Innovative and Integrated Sensors

In spite of the relentless growth of MEMS sensors, traditional technologies continue to solve tough measurement problems. For example, Rense Instruments HT-748 humidity and temperature transmitter (http://rbi.ims.ca/5406-594) uses a thin-film polymer capacitor with a dielectric constant that varies in direct proportion to the ambient relative humidity. The humidity sensor and a temperature sensor are assembled in a stainless-steel housing for operation up to 300F (150C). Based on this operating temperature range, the signal conditioning electronics are remotely mounted in a connector at the end of the cable.

In this section, Hall Effect sensors, temperature sensors, high pressure industrial sensors, photoelectric and three-axis sensors all demonstrate some aspect of integrated and/or innovative. While, the three-axis sensors use MEMS technology, Hall Effect sensors use integrated circuit (IC) technology and the temperature, pressure and photoelectric sensors use a mix of IC and other technologies.