The Sensor Revolution

The shift to mass production and use and very low cost will result in a proliferation of sensors everywhere—and new ways of doing things.

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“Sensors will transform manufacturing from now on,” said Eric Janson, senior vice president of sales and marketing at AMS (Austria Micro Systeme), an analog mixed-signal semiconductor manufacturer based in Austria.

There have been many such predictions in the past—lithography, processors, memory and various materials all have been predicted to change semiconductor manufacturing. But sensors? It may sound like a stretch—until you consider the role of sensors inside of smartphones.

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Figure 1. Eric Janson, senior vice president of sales and marketing at AMS.

Sensors have been viewed as a growing market for years, but in sheer numbers sensors have been a footnote for the semiconductor industry. A sensor inside of MEMS chips that can convert mechanical displacement or light into electricity showed up in industrial equipment and some parts of automotive within the past few years, for example. And aMEMS actuator, which works in reverse of the sensor, has found its way into inkjet printer heads and projector. But even though inkjet printer shipments are sizeable, they account for only about 70 million to 80 million units.

Smartphones are changing those economics. About 1 billion smart phones were shipped in 2013, forcing a shift from a relatively small number of expensive and complex MEMS sensors into a huge number of inexpensive sensors.

There are more types of sensors hitting the market these days, too. One smartphone contains more than 10 types of sensors (figure 2), including sensors for touch, acceleration (the ability to rotate the image together when the screen is rotated 90 degrees from portrait to landscape), magnetic readings (electronic compass), proximity (when talking using smartphone the screen darken and become bright when the smartphone is moved away from ear), and many more. Even the microphone has progressed from an electrolytic capacitor microphone to a MEMS microphone.

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Figure 2. More sensors will be used in smartphones in the future. Source: AMS

The impact of smartphones has a direct correlation to the rise of inexpensive sensors. But in the future, those inexpensive sensors will also start showing up a variety of other places, replacing the costly sensors that have dominated industrial applications. Add to that the need for massive numbers of sensors for the Internet of things, including everything from industrial equipment to automobiles, and the predictions about explosive growth begin to make sense.

Moreover, even in areas where sensors did exist, there will be more of them. A sensor can detect small anomalies in production equipment, allowing parts to be replaced before they cause a problem, reducing down time, and making businesses significantly more efficient. That opens up new opportunities outside of just the consumer electronics world, for concepts such as meter rate system business models and the Industrial Internet.

Even within smartphones, inexpensive sensors will have a big impact. The red character in figure 2 represents fingerprint sensors, chemical sensors, and blood pressure sensors. Fingerprint sensors already are included in Samsung’s Galaxy S5 and Apple’s iPhone 5s. A Pressure sensor that can measure atmospheric pressure and blood pressure is in the works, as well. The pressure measurement detects a difference in height with an error of about 30cm, which in combination with GPS can determine whether the user is on the second floor or the third floor of a building, for example.

And that’s just the beginning. In health care, blood pressure, blood sugar, jaundice, skin surface temperature and other bodily changes can be measured with a wearable device such as a watch or wristband. Janson wouldn’t predict whether wearable devices will go mainstream in future, but at least for now he is seeing those features showing up in smartphone companinon devices.

AMS’ focus is on the industrial sensor side for smart lighting, medical, automotive, and motor drives, and many other possibilities.

Smart lighting has been the focus of major development efforts lately. Consider that in one room, the brightness next to the window is significantly different than on the other side of a room. By attaching numerous optical sensors in the room, a smart lighting system can detect the brightness and vary the energy supplied to LED lighting in different parts of the room to create uniform brightness. That improves lighting while also saving money. The same approach can be used for temperature sensors in air conditioning and heating systems, as well, to provide a more uniform temperature.

For the medical field, AMS also developed an optical sensor with a TSV (through-silicon via) that increased sensitivity by 6dB for a for CT scanner. That, in turn, increased image resolution from 8% to 10%. That same improvement in resolution allows X-rays to provide equivalent accuracy at half the radiation levels.

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Figure 3: Magnetic sensors used in vehicles. Source: AMS.

In automotive applications, advancements are being made using magnetic sensors to detect machine parts. For example, by detecting the exact position (stroke) of the brake pedal, it is possible to realize a quicker braking action. That is indispensable to automatic operation. Figure 4 shows a sensor that can detect up to 50mm linear position of clutch and brake and gear box. In addition, it is used in off-axis rotation, and also brushless motor control for controlling rotation on the axis.

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Figure 4. Detecting the position by magnet, which moves linearly when the brake and clutch pedals are pressed. Source: AMS.

And for industrial equipment, in order to detect linear and rotational positions, an encoder utilizing a magnetic sensor and a Hall sensor are used. AMS is designing and manufacturing not only the sensor, but also the sensor signal amplification and A-D conversion for the IC interface. Further, substances can be detected with light sensors using an interference filter for chemical analysis and utilizing spectroscopy such as infrared (Reference 1). Instead of reacting directly with chemicals, as a chemical sensor would do, it ensures reliability because the substances are identified by measuring the light absorption.

In the Japanese market, because industrial and automotive are stronger than consumer electronics, AMS is focusing its efforts on these two markets.
Reference:
1. IR spectroscopy of palm size, thanks to the MEMS technology (2012/09/12)

The Japanese version of this article is located here.