欧洲研发“电子鼻”，可侦测各种气体

欧洲研究机构IMEC与旗下的Holst Center研究人员开发出一种性能更好的“电子鼻”；该种号称灵敏度高、耗电量却很低的气相传感器(vapor sensor)，据说能与无线网络结合，用以侦测各种气体，可供医疗照护或是食品业等领域使用。

上述研究成果是以所谓的微网桥(microbridge)数组做为基础，即一种会各自振动的悬吊式结构(suspended structure)；透过采用喷墨印刷技术，将各种不同的聚合物涂布于该种结构，由于聚合物对目标气相的吸收程度不同，就能改变微网桥的振动模式。

据研究人员表示，该种振动模式的改变细微到足以侦测目标气体的存在，其敏感度甚至可以达到几百万分之一。因此新研发的传感器可望取代各种传统的化学电阻(chemical resistor)或是石英晶体，而后者的那些组件已无法在功耗或尺寸上微缩，以符合无线感测网络应用需求。

IMEC所设计的MEMS传感器，会根据涂布了吸收性聚合物的微结构振动变化来识别各种气体

这种传感器整合了压电组件(piezoelectric elements)，能以低耗电量读取数据；研究人员指出，该传感器还能达到低于1微瓦(microwatt)的耗电，不过目前尚未达成高生产良率。

目前所制作出的8.8×8.8mm尺寸传感器耗电量为170纳瓦(nanowatt)，是同类产品的万分之一，不过性能却能进步260倍。IMEC的研究人员Mercedes Crego-Calama指出，这类组件的价格可能也不到100美元，而市面上的气体侦测系统不但体积大，还要价8,000美元。

IMEC的技术研发已经接近可用阶段，不过该机构还需要为该 MEMS传感器完成封装设计；不过Crego-Calama也表示，要重建市场对此类装置的期待是最大的障碍，因为到目前为止，这种电子鼻都无法达成最初承诺的效果。

在应用方面，这种传感器可藉由受测者的呼气样本，用以侦测气喘、肺癌、肾脏疾病甚至不良的饮食习惯；或是用来判断酒类或是吉士等食品的成熟度与质量，以及监测空气中的毒素或是污染物质等。

“这种传感器并不会取代人类的鼻子，但却可以整合在智能手机或是汽车中，提供多样化的应用。”Crego-Calama表示。

(参考原文： Update: Sensor aims to be low-power electronic nose，by Rick Merritt)

《电子工程专辑》网站版权所有，谢绝转载

{pagination}

Update: Sensor aims to be low-power electronic nose

by Rick Merritt

Researchers in Europe's IMEC and its affiliate the Holst Center here believe they have developed a better nose. The groups announced a design for a highly sensitive yet low power vapor sensor that can be tailored to detect a variety of gases for use on wireless networks in applications ranging from health care to the food industry.

The new design is based on an array of so-called microbridges, suspended structures that vibrate individually. Using inkjet printing technology, the structures can be coated with a wide variety of polymers that change the microbridges' vibration patterns based on the rate at which the polymers absorb target vapors.

The changes in vibration patterns are refined enough to be able to detect the presence of target gases down to sensitivity levels expressed in parts per million. The new sensors would replace more conventional chemical resistors or quartz crystals that cannot be scaled to the low power and size requirements needed for wireless sensor networks.

The sensors include integrated piezoelectric elements to read out data at low power levels. Researchers claim the sensors can be made in ways that consume less than one microwatt yet achieve high manufacturing yields.

The resulting 8.8x8.8mm sensors consume just 170 nanowatts, 10,000 times less than competing sensors while sporting a 260-fold performance boost, said Imec researcher Mercedes Crego-Calama. Such devices could cost far less than $100 compared to as much as $8,000 for today's gas detection systems that are the size of large walkie-talkies.

The technology is nearly ready, although Imec has finalized on packaging for the MEMS sensor yet. Re-setting market expectations is the biggest hurdle ahead, because the electronic nose devices have failed to meet early promises until now, Crego-Calama said.

The sensors could detect health conditions based ranging from asthma, lung cancer, kidney diseases and even poor diet based on breath samples. They could be used to determine the ripeness of produce or the quality of wines or cheeses or the presence of toxins or pollutants in the air.

"This will never be a replacement for a human nose, but the sensors could be integrated in smartphones or carCOUNTRY: Taiwan, USA