Paper - Micro Electromechanical System
Micro electro mechanical system(MEMS) describes both, the category of devices and technique for manufacturing them. These tiny devices have elements ranging in size from 1 to 100 microns about the thickness of a human hair. MEMS devices are generally divided into two categories: Sensors and Actuators. Sensor devices gather information from their surroundings and Actuators execute given commands or act generally through highly controlled movements.
MEMS are made using the basic fabrication techniques and materials of microelectronics. Slight layers of materials are put onto a base and then are selectively etched away leaving a microscopic three-dimensional configuration. In this way, MEMS processes construct mechanical as well as electrical components. Known as MST or Microsystems technology in EUROPE and ASIA, the potential for MEMS technology is endless. MEMS devices are already used in an extensive range of products. They can be produced in large quantities with proven fabrication techniques, for example, crash sensors for airbag safety systems are actually MEMS devices that measure the force of a novel crash and deploy an airbag if the force is great enough. Also with the help of MEMS print heads, inkjet printers have developed from crude slow black and white devices to fast flexible photographic quality images and thanks to MEMS digital micro mirrors that control light. Video projectors in offices around the world are now able to produce razor sharp bright colorful images. MEMS technology has become so widespread since its beginnings in the nineteen eighties that it is estimated that there are now 15 to 20 MEMS devices for every person living in north America.
There are two common examples of MEMS improving existing technology, the automotive crash sensor, and a digital micro-mirror device. A key element of modern automotive airbag systems is the MEMS crash sensor known as MEMS accelerometer. These sensors are more effective than earlier systems meeting more stringent safety standards. The core of the MEMS accelerometer is a central mass that moves in response to a vehicle's acceleration. This inertial mass is mounted on a hinge or spring that limits its movement and returns it to a central position when at rest. Sensitive electrical sensors in the chip Read the masses movement and relay this data to a connected microprocessor. The microprocessor monitors the state of the accelerometer at rest and in motion. In a collision there is a sudden change in acceleration when this change reaches an unsafe level, the airbags are deployed .the entire process takes only a fraction of second and has saved millions of lives. MEMS technology allows crash sensors to be built from one or two simple chips. Earlier systems needed many electrical and mechanical components located throughout an automobile for measuring the same data. Reducing the number of components increases the accuracy and lowers the cost of these systems. The MEMS micro mirror device or DMD chip is used in modern video projectors, home theater systems, and televisions. This chip uses microscopic moving mirrors to improve image quality and overall reliability of these products. The micro-mirror device is, in its simplest form, a light switch made of millions of hinge mounted mirrors. Each mirror measures about the one-fifth width of a human hair and correspond to one dot or pixel in a projected image. Mirrors are mounted on tiny hinges that enable them to tilt either toward the light source to reflect light or away from it to block the light. This creates a light or dark dot on the projection surface. The length of time the mirror faces the light, determines the brightness of each dot. In color systems, projectors can create over 16 million shades of color. These systems are producing such high-quality images that they are now being installed in movie theaters replacing film projectors.
MEMS technology will continue to quietly improve life as we move into the future. We may not be able to see the devices but we will see its applications as they continue to affect our lives. Since MEMS is a flexible technology, It has the unique ability to improve current products delivering a new level of performance and efficiency to both mass market and highly specialized applications. In the computer market, MEMS is revolutionizing mass data storage by miniaturizing components for the disk drive, servers, and peripherals, meeting the increasing need for low-cost high capacity digital storage. In the consumer electronics market, acoustic MEMS chips are changing the way sound reaches our ear through cell phones, personal stereos and hearing aids providing less distortion and higher quality and clarity of sounds. MEMS technology is meeting its potential for greater commercial use in several fields of technology. In addition, MEMS sighs and integration allows for whole new classes of products that would never have been possible with conventional approaches. In medicine, the advent of MEMS chips for drug delivery can benefit any patient who must follow a regimen for medication as a single chip embedded in a patient can release the correct amount of drug over a given period of time. Also, MEMS sensors embedded in the scalp holes allow surgeons to measure the force and depth of their delicate incisions. The industrial market will see MEMS chips that detect gas leaks and other pathogen agents keeping the workplace safe. MEMS technology is everywhere. It has become an inevitable part of the path to more effective and diverse products at the consumer level and beyond and has already improved our quality of life. Products with MEMS devices perform better respond faster and are more reliable. They improve current products in ways that are not possible with traditional electronics. The beauty of MEMS technology is that it is used in hundreds of products today making it the technology of the present but has the proven potential to be in millions of more products in the future. Thus securing its role as the technology of tomorrow MEMS realizes the potential.