OREANDA-NEWS. Micro-electro-mechanical systems (MEMS) are the eyes and ears – and every other sense – of modern mobile devices. Bosch is using these tiny high-tech helpers to teach cars and modern electronic devices how to sense the world around them. Originally developed for automotive electronics systems, these components can now be found in smartphones, laptop and tablet computers, games consoles, and sports watches. Many of the latest functions for cars and electronic devices – including the ESP® electronic stability program and the use of gestures rather than keys to operate smartphones – would be unthinkable without these highly sensitive measuring instruments.

 Bosch supplies sensors for a wide range of applications in the consumer electronics and automotive industries. These sensors measure pressure, acceleration, rotary motion, mass flow, and the earth’s magnetic field. Bosch has been at the forefront of MEMS technology since it first emerged, and today it generates more sales in the extremely dynamic MEMS sensor market than any other supplier. Since the start of production in 1995, the company has manufactured well in excess of three billion MEMS sensors, with production volumes hitting new highs year after year. It took Bosch 13 years to manufacture the first billion, another three years to reach two billion, and only a further 18 months to cross the three-billion mark. In 2012, some 600 million sensors emerged from its state-of-the-art wafer fab in Reutlingen – or 2.4 million each working day.

 “It’s no longer possible to imagine automotive or consumer electronics without MEMS sensors. In the future, they will act as the eyes and ears for systems and objects connected via the internet of things and services,” says Klaus Meder, president of the Bosch Automotive Electronics division.

Tiny high-tech helpers for vehicles and smartphones
MEMS sensors are the smallest products Bosch manufactures. Their first application was in automotive electronics and Bosch has been producing these precision sensors for use in vehicles since 1995. A yaw-rate sensor that records the rotary movements of the car around its vertical axis is at the heart of ESP®, for example, and today each modern vehicle is home to up to 50 MEMS sensors. In an automotive context, the key considerations for MEMS are their reliability and robustness, as the sensors have a direct impact on the safety of road users. Size and energy consumption are much less important factors. But the picture is quite different when it comes to smartphones or games consoles, which is why Bosch shrunk its sensors over the years to just one fiftieth of their former size. The latest generation of these sensors unites a host of functions in a casing measuring just a few square millimeters. Meanwhile the sensors’ energy consumption has been reduced by a factor of 100. Of all the suppliers in the market, Bosch is the only one producing sensor types for so many different applications. The company holds or has applied for a total of well over 1,000 patents, thereby safeguarding its innovative strength.

Bosch Sensortec
In order to react quickly and flexibly to requirements in the extremely dynamic consumer electronics market, Bosch Sensortec GmbH in Reutlingen was founded in 2005. This Bosch subsidiary recently brought the world’s first 9-axis sensor to market. The BMX055 is capable of measuring acceleration, yaw rate, and the earth’s magnetic field in all three spatial directions at the same time, which makes it suitable for a whole range of potential applications. The sensor can be put to work wherever there is a need to pinpoint a mobile device’s spatial location and position – or its orientation relative to the earth’s magnetic field – and can be integrated into even the smallest devices.

MEMS sensors – technical background
Engineers create incredibly fine silicon structures inside the sensors that shift by fractions of a micrometer when the casing is moved. This alters their electrical properties, which is something that can be measured and converted into a data stream, telling a cell phone for example what position it is currently in. Bosch engineers are working with dimensions that are incredibly small: while a human hair has a diameter of 70 thousandths of a millimeter (70 micrometers), some sensor components measure just 4 micrometers – 17 times less than a single hair.

 Since micromechanical sensors produce only weak electrical signals, experts have integrated additional electronics either into the component housing beside the sensor or sometimes even directly onto the same chip. These take the weak signal, then process it, amplify it, and convert it into digital data. In this way, MEMS sensors can provide measurements directly to control units. And these precision sensors will soon be able to do much more, whether sewn into articles of clothing to measure your heart rate, serving as mobile weather stations, measuring CO2 concentrations in the air, or picking up the typical movements we make when pocketing our cell phones so as to deactivate the display.