MEMS
A 40-year-old technology, MEMS devices by the 1990s became commonplace in airbag sensors and air pressure sensors in cars, inkjet printer heads and blood pressure monitoring devices, just to name just a few.
Each of these many industrial sectors aclearcase/" target="_blank" >ccount for hundreds of millions of MEMS devices sold every year in a marketplace now exceeding $10 billion a year in sales. Today, though, the MEMS industry is poised to enter the multibillion-dollar consumer products marketplace in force, led by major specialized semiconductor manufacturers such as Texas Instruments, Analog Devices and Robert Bosch, as well as a host of creative, venture-capital-backed start-ups.
These companies are pushing MEMS devices into increasingly sophisticated display technology, motion detection (to protect cell phones and laptops from breaking during a fall), even microphones. The growing range of MEMS applications may soon encompass most of the massive global consumer electronics marketplace.
Some of these consumer-related MEMS applications are already entering the marketplace, others may be only a few years away from commercialization. And if the market develops as analysts expect, the total worldwide market for MEMS will grow from $11.5 billion in 2004 to $24 billion in 2009. Consumer products will help drive the doubling of those sales figures, especially digital displays in TVs, mobile phones and other handheld devices, laptop computers and digital cameras, microwaves and washing machines.
MEMS technology is an outgrowth of the highly sophisticated semiconductor industry. Microelectromechanical systems integrate moving mechanical elements, sensors and electronics on pieces of silicon. A typical MEMS device is indeed an engineering marvel that brings together integrated circuit manufacturing processes with “micromachining” to etch away or build up silicon structures of moving parts. The result is a microscale device that combines computational ability with the sensing and control functions of exquisitely sensitive sensors.
The first commercial MEMS devices evolved from the mid-1960s, reaching high-volume production in the 1990s. Since then, industries that absolutely require high-precision MEMS devices, such as automakers, have continually integrated them into high-priced products, passing the cost onto consumers. Meeting the low price demands of mass production (yet low safety) manufacturers of electronic mobile consumer products at a high volume is a very different challenge for MEMS suppliers.
For starters, few MEMS devices are truly “monolithic,” meaning they combine the micromachined silicon structure and electronics on the same chip. More often, the micromachined part and electronics are fabricated separately and then wire bonded together in a single package.
Digital television displays are the most significant and growing arena for MEMS. Texas Instruments dominates the optical MEMS market for digital displays with its digital light processing technology, or DLP.
The heart of DLP is an array of up to 2 million hinge-mounted aluminum micromirrors, known as digital micromirror devices, or DMDs. The mirrors——each about 14 microns wide, or one-fifth the width of a human hair——reflect a digital image from a light source onto a screen. The mirrors tilt toward or away from the light source, creating light or dark pixels; white light, such as a florescent light, is projected through a color wheel to create color.
DLP technology today accounts for one in five very large (more than 40-inch diagonal) digital TV displays, where it competes with more established technologies such as the venerable cathode ray tube as well as liquid crystal and plasma displays, and new technologies such as organic light-emitting diodes. And it’s an important and growing market. Overall, digital TV sales are projected to grow to 9 million units in 2007. Other major markets for MEMS displays are DLP front projectors and commercial cinema.
微型機電系統
MEMS是一項有40年曆史的技術，在上世紀九十年代，MEMS裝置在汽車的氣囊感測器和氣壓感測器、噴墨列印頭和血壓檢測裝置等多種筆記者電腦設備中成了常見之物。
在這些多種多樣的行業中，每一個行業類都用了數以億計的MEMS裝置，每年在市場上的銷量超過100億美元。今天MEMS工業在德州儀器、模擬器件、博世等專業的半導體大廠商帶領下，一大批風險資本支持的創新企業正昂首闊步地進入幾十億美元的消費品市場。
這些公司將MEMS裝置應用到了日益複雜的顯示技術、運動檢測（以防止手機和便攜機跌落時摔破）、甚至麥克風中。不斷擴大的MEMS應用不久將佔領大多數的消費電子市場。
有些與消費者有關的MEMS應用已經進入了市場，其他的應用離商品化也只是幾年之遙。如果市場的開發如分析師所言，MEMS的全球市場將從2004年的115億美元增長到2009年的240億美元。消費產品，特別是數字電視機、移動電話及其他的手持設備、數碼相機、微波爐和洗衣機，將使MEMS的銷售量翻一番。
MEMS技術的增長超過了已經非常先進的半導體工業。微型機電系統將活動的機械部件、感測器和矽片上的電子電路集成在一起。實際上，典型的MEMS裝置是工程上的一項奇跡，將積體電路製造工藝與“微型機加工”結合起來，刻蝕或構建出矽結構的活動部件。其成果是這種尺寸微小的裝置將計算能力與極其靈敏的感測器的傳感和控制功能結合起來。
第一批商品化的MEMS裝置是從上世紀六十年代中期發展起來的，到九十年代達到了批量生產。從那時起，絕對需要高精度MEMS裝置的行業，如汽車製造業，持之以恆地將MEMS裝置做進高價位的產品，將成本轉嫁給了消費者。滿足低價位的大批量生產（也是低安全性）的電子移動消費產品製造商的需要，對MEMS供應商來說是一個完全不同的挑戰。
對於剛起步的新公司來說，很少有真正是“單片式”MEMS裝置，所謂單片式就是在同一晶片上將顯微機械加工的矽結構與電子電路結合起來。通常，顯微機械加工的部件和電子電路是分開製造的，然後在同一封裝塊內用線將它們連在一起。
數字電視顯示是MEMS最重要、發展最快的領域。德州儀器公司以其數字光處理技術（DLP）控制著MEMS的數字顯示器市場。
DLP的心臟是一個多達200萬個安裝在鉸鏈上的微型鋁鏡（稱作數字微鏡裝置，即DMD）陣列。這些微鏡，每個只有14微米寬，為人的頭髮絲的五分之一，將來自光源的圖像反射到螢幕上。微鏡相對於光源進行轉動，造成像素的或明或暗。白光，如日光燈的光，通過色彩輪投射出去，從而產生顏色。
今天，DLP技術佔據了兩成的大螢幕（對角線超過40英寸）數字電視顯示器的市場，它正與早已入市的老式陰極顯示管以及液晶和等離子顯示器、以及諸如有機光發射二極體等新技術進行競爭。這是一個重要的、發展中的市場。預計到2007年，數字電視的銷量將達到900萬臺。MEMS顯示器的其他市場還包括DLP正向投影機和商業電影院。 |
