Design of a microcamera using a silicon based closed-loop microdeployable structure

The ability of a MEMS device to stretch a flexible lens (similar to a crystalline lens of the human eye) has far reaching consequences in the miniaturization of current commercial optical systems. A closed-loop mierodeployable structure was designed and surface micromachined in Sandia's SUMMiT-Vâ„¢ process as a proof-of-concept for conversion of rotational to radial motion. This same basic mierodeployable concept was then modified to produce two key components in a microscale camera: a microautofocus mechanism and a microaperture. The inicroautofocus component couples a polymer lens to the closed-loop mierodeployable; as it deploys open, it stretches the polymer lens radially, at eight fixed areas, around the circumference of the lens. The lens deformation in turn causes a focal plane change. The ability to change the focal plane is advantageous to portable digital imaging devices such as the cell phone camera and the mini-digital camera. Further adaptation of the original mierodeployable by the placement of solid plates instead of bar linkages produces a microaperture, which has a stop range of 7/2.8 to / / 5 . 6 . Each of these components is integrated at the die level with a digital imaging sensor to produce a mieroeamera of dimensions 1.8mm x 2.0mm x 2.0mm.