MEMS电子鼻让你的手机也拥有嗅觉

微机电系统(MEMS)的下一步目标在于缩小可用于分析气味的电子仪器，如质谱仪以及几乎能嗅出任何物质的电子鼻。透过Honeywell公司开发出的首款微型 MEMS 真空泵，其尺寸小到足以塞进一支手机中，可望让下一代智能手机等移动装置也能拥有“嗅觉”。 Honeywell最初开发这款微型 MEMS 真空泵主要针对军用的微型无人侦察机，使其得以用于侦测化学与生物制剂。如今，这款仅1美分钱币大小的MEMS传感器正着眼于扩展应用领域至工业、医疗与消费市场。

Honeywell的微型MEMS真空帮浦利用像涡轮的叶片实现手持式分析仪
Source：HoneywellDL5esmc

“我 们已经开发出世界上最小的真空泵，这是一款能实现电子分析仪新型态的独特技术，”Honeywell公司ACS Labs业务单位首席研究科学家Wei Yang指出，“近年来有很多人都试图缩小电子分析仪，但这种真空泵是最近的一项突破。先前最小的模型约为砖块大小，功耗为100W，如今，我们开发出的 这款真空泵只有1美分硬币大小，功耗还不到1W。” 这款组件原先是依据与美国DARPA的合约而开发的，主要安装于微型无人 机上明。如今，Honeywell期望使该组件商用化，让这款微型真空泵可应用在各种移动装置上──从能够确定任何物质组成的质谱仪，到可提供超精确导航 服务的原子钟──让手机与移动装置在拥有听觉(语音)、视觉(视频)与触觉(触控)以外，现在还有了嗅觉。 Wei Yang强调，“最让我们感到兴奋之处在于它也能内建于智能手机中，让手机能真的拥有嗅觉，可以闻出有毒化学品、花粉与一般空气品质等任何物质与气味。它还能为用户持续累积暴露记录，提醒用户暴露于某个环境的时间与地点。” 由 于目前的传感器主要依据化学反应，使其受限于特定的几种毒素侦测。事实上，针对每一种化学物质都必须采用不同的传感器来侦测，使其仅适用于特定目的(如一 氧化碳或烟雾侦测器)，而无法作为一种通用的嗅探器。然而，可内建于手机中的这种质谱仪能够侦测样本中的元素、各种储存于数据库中已知毒物的化学特性，以 及同步搜寻比对最可能组合。 DARPA以及其它单位过去也曾经试图缩小质谱仪等电子分析仪。遗憾的是，这些芯片级的仪器仅在真空状态下才能有效隔离与分析样本。因此，Honeywell藉由缩小真空泵的方式，可说是突破了最后一道障碍，并为能嗅出几乎任何化学物质的手持式嗅探器应用开启了大门。 Wei Yang预期“在未来的十年，这一创新将为手持式移动装置迎来各种先进复杂的电子分析仪。” Honeywell 得以成功实现这款号称全球最小真空泵的关键是在1公分大小的磁盘上制造出10万个微小涡轮叶片。Honeywell已经拥有可开发出微米级涡轮叶片的 MEMS技术，还能在与其MEMS设备相同的设备上进行制造。每一个8 寸晶圆上大约可制造出几百个搭载这种涡轮叶片的磁盘。 “我们的MEMS真空泵延续Honeywell在MEMS技术上的长期发展经验。事实上，我们在制造这款真空泵时，采用的就是我们生产MEMS陀螺仪与流量传感器所用的相同光学微影制程与相同设备，”Wei Yang表示。 每个真空泵中包含两个磁盘──一个固定磁盘以及一个旋转磁盘，其上覆以10微米大小、类似涡轮的叶片。每一组叶片彼此相对，从而形成强大的吸附效果，以便在小型样本导入测试前先行清空测试腔。 DARPA已经将Honeywell的真空泵安装在微型无人 机的移动分析仪了。Honeywell目前正致力于扩大其传感器网络，并提供内建手持单元的首款转发器。不过，据Wei Yang表示，最大的好处就是整合于智能手机等消费移动设备中。 “当每个人的手机中都安装了这种组件，可望实现追踪一切物质化学组成的未来──从空气品质到疾病控制，甚至化学药品。同时还能实时动态追踪任何化学物种，并在地图上观察其实时移动情形。” 本文授权编译自EE Times，版权所有，谢绝转载 编译：Susan Hong 参考英文原文：MEMS-Enabled Electronic Nose Is Nothing to Sneeze At，by R. Colin Johnson

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{pagination} MEMS-Enabled Electronic Nose Is Nothing to Sneeze At R. Colin Johnson PORTLAND, Ore. — Next on the frontier for micro-electromechanical systems (MEMS) is the downsizing of analytic instruments like mass spectrometers -- essentially electronic noses that can sniff out nearly any substance. The enabling technology is the world's first MEMS vacuum pump small enough to fit inside a mobile device. Invented at Honeywell to enable military micro-drones to detect chemical and biological agents, these penny-sized MEMS vacuum pumps are now poised to enter the industrial, medical and consumer markets. Honeywell's penny-sized vacuum pump (upper right) enables handheld analytic instruments by virtue of MEMS turbine-like blades. (Source: Honeywell) "What we have done is create the world's smallest vacuum pump -- a unique enabler for a whole new class of analytic instruments," Wei Yang, principal research scientist with Honeywell's ACS Labs business unit, told us. "Many people have tried to downsize analytical instruments in recent years, but the vacuum pump was the last obstacle. Previously the smallest models were brick sized and consumed 100 watts, but ours is now penny sized and uses less than one watt." The device was invented under a contract with the Defense Advanced Research Project Agency (DARPA) for installation on micro-drones. Honeywell is hoping to market these vacuum pumps as an "add-on sense of smell" for all sorts of mobile devices -- from mass spectrometers that can determine the composition of any substance to atomic clocks that provide ultra-precise navigation services. "One thing we are very excited about is putting these into smartphones, essentially adding a sense of smell that can sense everything from toxic chemicals to pollen to general air quality," Yang said. "They could keep a cumulative record of exposure for every person carrying one, noting when and where a user was exposed." Today sensors are restricted to specific toxins, because they are based on chemical reactions. In fact, a different sensor is needed for each type of chemical to be sensed, making them useful for specific purposes (such as carbon monoxide or smoke detectors) but useless as general-purpose sniffers. But with a mobile mass spectrometer that detects the elements in a sample, the chemical signatures of all known toxic substances could be stored in a database and searched in real-time for the most likely match. DARPA and others had previously downsized the components for analytic instruments like mass spectrometers. Unfortunately, these chip-sized instruments work only in a vacuum, where the sample can be isolated for analysis. By downsizing a vacuum pump to chip size, Honeywell has removed the last obstacle, opening the door to handheld sniffers that can sense almost any chemical species. "In the coming decade, this innovation is going to usher in all types of very sophisticated instrumentation for handheld mobile platforms," Yang said. Key to the success of the world's smallest vacuum pump was the fabrication of more than 100,000 tiny turbine blades on a centimeter-sized disk. Honeywell already had the MEMS technology to create the micron-size, turbine-like blades. In fact, it fabricates them on the same equipment as its other MEMS devices. Hundreds of such bladed disks can be manufactured on each eight-inch silicon wafer. "Our MEMS vacuum pump follows a long legacy of Honeywell MEMS developments," Yang said. "In fact, the vacuum pump is made from silicon monolithically with the same photolithographic processes and same equipment that we use to produce our MEMS gyroscopes and flow sensors." Each vacuum pump houses two disks -- one stationary and one rotating -- covered with 10 micron-sized, turbine-like blades (shown above). The pairs of blades face each other to create the strong suction effect necessary to evacuate a test chamber before a small sample is bled in for testing. DARPA is already working to install Honeywell's vacuum pumps into mobile analytic instruments on micro-drones. Homeland security contractors are working to expand their sensor networks with these devices and provide first responders with handheld units. But the biggest benefit, according to Yang, will come from integrating them with consumer mobile devices like smartphones. "With these installed in everybody's smartphones, the tracking of the chemical constituents for everything from air quality to disease control to chemical spills is possible," Yang said. "You could have instant real-time dynamic tracking of any kind of chemical species and watch it moving in real-time on a map."