EL SEGUNDO, USA: Thanks to their relatively high prices and expanding use in a host of automotive, medical and industrial applications, pressure sensors will become the leading microelectromechanical systems (MEMS) device by 2014, according to an IHS iSuppli MEMS & Sensors Market Tracker.
Driven by a strong automotive industry recovery after the recession, pressure sensors last year generated $1.22 billion in revenue, up 26 percent from 2009, to reach second place in terms of revenue among all MEMS devices. Growth this year will be more modest at 6.6 percent, but a double-digit expansion is predicted for 2012. By 2014, revenue for MEMS pressure sensors will amount to $1.85 billion, as shown in the figure.Source: IHS iSuppli, USA.
“Pressure sensors will become the top MEMS device in revenue in three years’ time as a result of steady market expansion,” said Richard Dixon, Ph.D., senior analyst for MEMS and sensors at IHS. “The rapid growth of pressure sensors means that these devices will trump even the ubiquitous accelerometers and gyroscopes so popular now in the MEMS space.”
The average price of MEMS pressure sensors varies, depending on the level of compensation and calibration of the die, as well as the type of packaging. Pricing could range from several dollars to tens of dollars for high-value industrial and medical uses, and climb to hundreds of dollars for the most specialized applications, such as aircraft hydraulics or air data measurements—including any combination of industrial use in harsh media, temperature and pressure, Dixon noted.
MEMS pressure sensors find heavy use in assorted applications
A MEMS pressure sensor is a membrane element that deflects under pressure. The deflection can be measured by either a Wheatstone bridge arrangement—piezoresistive-type sensing—or by a change in the distance between two plates via capacitive sensing. Both approaches are popular, with the piezoresistive type found, for example, on tire-pressure monitoring systems.
The automotive sector remains in 2011 the biggest area for MEMS pressure sensors, claiming 72 percent share in revenue, followed by medical electronics at 11 percent and the industrial segment at 10 percent. The remaining 6 percent of the market is split between consumer electronics on the one hand, and military-aerospace on the other.
In the automotive sector, engine management is a leading application in the form of manifold air pressure sensors in petrol engines and common fuel rail pressure sensors for diesel cars, especially in Europe. For improved combustion, some organizations are also undertaking research on pressure sensors that can survive inside the vehicle’s cylinder to better measure the exact stoichiometry—the proportion of elements in a chemical reaction—for feedback to engine management systems.
Automotive sensors are significantly more expensive than consumer sensors due to the often harsh environments in which the devices operate. Moreover, long qualification times are needed for the sensors, which also need to be reliable for stretches of time lasting as long as 15 years. Some devices, such as brake or tire pressure monitors, are critical to the safety of vehicles.
One new automotive application of MEMS pressure sensors can be found not only in automatic transmission but also increasingly in new double-clutch transmission systems as well as manuals due to the requirement on greater precision for control. Different kinds of sensors are possible, and German manufacturer Bosch recently entered this market with a MEMS solution in which the oil acts directly on the back of the silicon sensor (a so-called backside-entry design) with pressures of up to 70 bar.
In the medical market, pressure sensors are used mostly as low-cost disposable devices for catheters employed in surgical operations. But they also can be found in more expensive devices used for pressure and differential flow monitoring in continuous positive airway pressure (CPAC) machines for treating sleep apnea—with significant potential as implantable sensors after 2015. Operating without the need for batteries, implantable sensors can be used for cardiac measurements and to monitor for glaucoma in the eye.
Within the industrial sector, big segments for MEMS pressure sensors include the heating, ventilation and air conditioning (HVAC) sector, level measurements, and various industrial process and control applications. Aircraft, for instance, use the sensors to monitor engines, flaps and other functions, in addition to precision altitude air pressure measurement.
MEMS pressure sensors not so hot in consumer and mobile devices
MEMS pressure sensors to date have not been used as much in the consumer electronics and mobile space, where their revenue is under $50 million today. Among their diverse applications, however, are weather stations, sport watches, bike computers, diving equipment and pedometers, along with white goods—such as water-level sensors employed for energy-efficient washing machines.
For the mobile segment in particular, no major application has emerged so far. High-end smartphones in the future could include pressure sensors to act as an altimeter for location-based services indoors, though the infrastructure is not yet in place. In tablets, the only use for pressure sensors thus far is to adjust the device to show local weather conditions.
As a result, compared to the uptake of accelerometers and gyroscopes in consumer and mobile devices, the use of pressure sensors here during the next few years will remain very modest.
Source: IHS iSuppli, USA.