Compliant mechanism and method of forming same

#1. Field of the Invention

#This invention relates to a mechanism that can be used to make a variety of devices where precise positioning of a device element is desirable. Examples include tunable optical elements such as mirrors, lenses, filters, prisms and diffraction gratings for use in tunable optical devices.

#2. Background of the Related Art

#Preferred embodiments of the invention will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein:

#FIG. 1 is a cross-sectional view of a compliant mechanism, in accordance with an embodiment of the present invention;

#FIG. 2 is a cross-sectional view of an actuated device utilizing the compliant mechanism of FIG. 1, in accordance with one embodiment of the present invention;

#FIG. 1 shows one embodiment of the compliant mechanism 100 of the present invention. The compliant mechanism 100 includes an island 105, which is suspended from a frame 115 using a compliant member 110, which is attached to the frame 115 and the island 105. The junction or interface where the island 105 meets the compliant member 110 is the first interface 120. The junction or interface where the compliant member 110 meets the frame 115 is the second interface 125. The exterior surface of the frame 115 includes an outer frame edge 130.

#The island 105 is preferably formed from a material that is more rigid than the compliant member 110, and preferably has a higher Young's modulus than the compliant member 110. Examples of such materials include polymers and other organic materials. The compliant member 110 is preferably an elastic material, preferably a polymer with a Young's modulus smaller than the Young's modulus of the island 105 and frame 115, and preferably has a relatively high elastic limit. In one preferred embodiment, the Young's modulus of the compliant member 110 is preferably less than 1 G Pascal. In embodiments where it is desirable to maintain the rigidity of the island 105 while the compliant member 110 is deformed, it is preferred that the Young's modulus of the island 105 is at least two orders of magnitude larger than the Young's modulus of the compliant member 110. Materials such as elastomers can offer Young's modulus as much as five orders of magnitude less than the Young's modulus of a typical silicon substrate. The frame 115 is preferably formed from a rigid material, which may be the same material used for the island 105.

#To have the capability to achieve large motion or displacements, the compliant member 110 should preferably display linear-elastic behavior over a wide range of frequencies and over a substantial portion of the deformation range at low actuation forces. Entropic materials, such as elastomers, aerogels and other long-chained polymers, are one type of material which provides such behavior.