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MOEMS technology combining MEMS and micro-optics is well suited for manipulating light. A number of different ways can be envisioned to scan, steer, or modulate light beams using tiny electromechanical structures. MEMS mirrors or microlens arrays can be used to change the light beam propagation direction for scanning or modulating the beam, and diffraction gratings, optical choppers, or microinterferometers can be used as light modulators. MOEMS technology allows a large array of micromechanical light manipulators to be batch-fabricated at low cost. A good example of a successful MOEMS display product is the Texas Instruments digital micromirror device (DMD) display, which probably has the largest number of moving mechanical components (over 1 million) of any product. On the other hand, there are several cases where MEMS technology has not provided any performance and/or cost advantages over other methods of machining and assembly of components and devices.
A number of MOEMS display and imaging products and technology demonstrators have been developed for defense, aerospace, industrial, medical, and consumer markets in the form of wearable displays, projection displays, imaging devices, barcode readers, and infrared imaging cameras. There are several alternative system architectures for these devices. In scanning beam systems, one biaxial or two uniaxial scanners can be used to draw a 2D raster pattern at some distance from the scanners, and they can be used to display or capture information. Alternatively, an array of micromechanical devices can be used to produce a line or a 2D array of pixels. Each pixel is a microelectromechanical element that displays or senses different pixel intensities or gray levels.
This chapter discusses the application of MEMS technology for displays and visible and IR imaging systems. In the display section, examples of scanning beam and pixel-based display technologies are discussed. The imaging systems section discusses scanning-beam imaging systems and their applications (confocal microscopy, ladar, etc.), aberration correction systems to enhance the capability of scanning systems, and array-based IR imaging systems (such as thermal cameras).
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