Micromachined scanning mirrors are interesting for a wide variety of
applications because of their potential low cost, high speed, low power
consumption, and reliability. These mirrors can offer significant
advantages over macro-scale mirrors, but the fundamental limitations of
scanning mirrors have not been widely discussed.
Miniaturization in electronic systems has led to radical improvements in
computers and communications, and micromachining technologies promise to
generate such improvements in miniaturized mechanical and optical
systems, including specifically higher-speed, smaller, lower-cost
scanning mirrors. Micromachined Mirrors provides an overview of the
performance enhancements that will be realized by miniaturizing scanning
mirrors like those used for laser printers and barcode scanners, and the
newly enabled applications, including raster-scanning projection video
displays and compact, high-speed fiber-optic components.
There are a wide variety of methods used to fabricate micromachined
mirrors - each with its advantages and disadvantages. There are,
however, performance criteria common to mirrors made from any of these
fabrication processes. For example, optical resolution is related to the
mirror aperture, the mirror flatness, and the scan angle.
Micromachined Mirrors provides a framework for the design of
micromirrors, and derives equations showing the fundamental limits for
micromirror performance. These limits provide the micromirror designer
tools with which to determine the acceptable mirror geometries, and to
quickly and easily determine the range of possible mirror optical
resolution and scan speed.
Micromachined Mirrors presents descriptions of mirrors made from two
fabrication processes - the surface-micromachining process and the
staggered torsional electrostatic combdrive (STEC) high-aspect ratio
micromachining process. The mirrors made using these two processes are
evaluated for scan speed, optical resolution, ease of manufacture, and
reliability.
Micromachined Mirrors also presents an example application of
surface-micromachined mirrors: a raster-scanning projection video
display. This demonstration shows the advantages of micromachined
mirrors (small high-speed scanners) with special attention paid to the
major drawback of surface-micromachined mirrors (lower resolution due to
dynamic deformation). The successful demonstration of this simple
prototype video display helps clarify the importance of the critical
performance characteristics to consider when designing micromachined
mirrors.
