The Art and Signs of a Few Good Mechanical Designs in MEMS
53
hierarchy where the same design exists at three different size scales, albeit with
reduced cross-sectional sizes like in the flow paths. Solid structures at the macroscale are replete with hierarchical designs (e.g., bridges and towers) but MEMS
structures are yet to exploit it. Nevertheless, it is a trait of good design that leads to
economic and efficient use of material.
11 Prospects for MEMS Design
In the last nine sections, we elaborated on nine traits of good MEMS designs with
examples. As can be seen here, good designs share one or more traits. Simple designs
are easy to make. Many of them are general in the sense that they can be used in
other design situations.
A few simple designs serve as building blocks so that modular structures can
be conceived. The “array” principle dominates MEMS designs. Just like a single
transistor is not useful in itself unless millions of them combine to give a processor
chip, the MEMS field uses arrays of single or multiple elements. Many examples
presented in this chapter illustrate this. This is not as widely seen in macro-mechanical
systems.
It is fair to conclude that MEMS designs depended on intuition and experience at
the inception of the field. Later, optimization was used to aid intuition and somewhat
automate the design process. There is much more to do in optimal design. It poses
challenges as most MEMS devices operate in multiple energy domains [38, 43].
Therefore, multiphysics leading to coupled partial differential equations make design
a challenging task. Several examples of optimizing in multiphysical domains were
reported in [2].
Enhancing the quality factor of MEMS structures is a continuing challenge and
a great opportunity to come up with innovative designs. Many modes of dissipation
exist. Many clever designs that minimize dissipation are reported [44, 45]. Systematic
study of the phenomena and how we can gain insights into their design are exciting
avenues for further research on MEMS design.
Incorporating multiple materials in a single design and finding interesting combinations is also a future prospect in MEMS. Finally, many MEMS devices are focused
on sensors. Actuators and mechanisms are far fewer. While we can argue that the
demand drives designs (i.e., we needed microsensors more than microactuators),
good designs can create demand. Upcoming areas of micro- and nano-robotics surely
will venture into actuators and mechanisms, thus giving rise to new designs. Good
designs in the future might have more than nine traits that are discussed in this
chapter. Many consider design as an art. And there are surely some revealing signs
to spot good designs also to conceive them either intuitively or systematically.
Finally, it is important to note that a design conceived in one situation for one
application could be used by others in another situation. An example is that of a
continuous-membrane mirror of [46] used in [8] for an array of beams that move
down without distortion, as discussed in Sect. 5. Good designs are always recognized
53
hierarchy where the same design exists at three different size scales, albeit with
reduced cross-sectional sizes like in the flow paths. Solid structures at the macroscale are replete with hierarchical designs (e.g., bridges and towers) but MEMS
structures are yet to exploit it. Nevertheless, it is a trait of good design that leads to
economic and efficient use of material.
11 Prospects for MEMS Design
In the last nine sections, we elaborated on nine traits of good MEMS designs with
examples. As can be seen here, good designs share one or more traits. Simple designs
are easy to make. Many of them are general in the sense that they can be used in
other design situations.
A few simple designs serve as building blocks so that modular structures can
be conceived. The “array” principle dominates MEMS designs. Just like a single
transistor is not useful in itself unless millions of them combine to give a processor
chip, the MEMS field uses arrays of single or multiple elements. Many examples
presented in this chapter illustrate this. This is not as widely seen in macro-mechanical
systems.
It is fair to conclude that MEMS designs depended on intuition and experience at
the inception of the field. Later, optimization was used to aid intuition and somewhat
automate the design process. There is much more to do in optimal design. It poses
challenges as most MEMS devices operate in multiple energy domains [38, 43].
Therefore, multiphysics leading to coupled partial differential equations make design
a challenging task. Several examples of optimizing in multiphysical domains were
reported in [2].
Enhancing the quality factor of MEMS structures is a continuing challenge and
a great opportunity to come up with innovative designs. Many modes of dissipation
exist. Many clever designs that minimize dissipation are reported [44, 45]. Systematic
study of the phenomena and how we can gain insights into their design are exciting
avenues for further research on MEMS design.
Incorporating multiple materials in a single design and finding interesting combinations is also a future prospect in MEMS. Finally, many MEMS devices are focused
on sensors. Actuators and mechanisms are far fewer. While we can argue that the
demand drives designs (i.e., we needed microsensors more than microactuators),
good designs can create demand. Upcoming areas of micro- and nano-robotics surely
will venture into actuators and mechanisms, thus giving rise to new designs. Good
designs in the future might have more than nine traits that are discussed in this
chapter. Many consider design as an art. And there are surely some revealing signs
to spot good designs also to conceive them either intuitively or systematically.
Finally, it is important to note that a design conceived in one situation for one
application could be used by others in another situation. An example is that of a
continuous-membrane mirror of [46] used in [8] for an array of beams that move
down without distortion, as discussed in Sect. 5. Good designs are always recognized