Microelectromechanical system (MEMS) technology is known in the art. This art pertains generally to the fabrication and provision of small electro-mechanical components such as switches or the like. It is known, for example, to employ printed wiring board fabrication techniques to fabricate microelectromechanical system components having a footprint of about 1 to 10 millimeters by about 1 to 10 millimeters. Components of this size are sometimes denoted as representing a medium-sized microelectromechanical system element.
Prior art knowledge encompasses the use of microelectromechanical system fabrication techniques to provide an optical switch. For example, an optical mirror can be placed on a movable cantilevered beam. Electrostatic forces are then used to urge the beam towards a particular orientation to thereby selectively alter a deployed angle of the optical mirror. This, in turn, can serve to control the angle by which a light beam will reflect from that optical mirror and hence can control a resultant direction of subsequent propagation (i.e., the relative angle of the optical mirror as corresponds to deployment of the beam serves to switch a resultant optical path of reflection as between two potential paths).
In many cases, the rotational range through which such an optical mirror can operate will depend in large part upon the corresponding degree of movement permitted by the beam itself. This, in turn, will depend at least in part upon the capacitor gap within which the beam typically moves. By increasing this capacitor gap, one also increases the permitted range of movement for the beam and hence also increases the rotational range of the optical mirror.
When increasing the capacitor gap, however, one also typically increases the electrostatic force required to effect desired movement of the beam. As electrostatic force is inversely proportional to the square of the initial capacitor gap while also being proportional to the square of the actuation voltage, the actuation voltage (and typically the size of the actuating capacitor elements) will also increase in size as the electrostatic force increases to correspond to a larger capacitor gap.
As a result, the capacitor elements may become large enough to result in physical contact with the beam. This, in turn, can lead to electrical short circuits and other related problems. Even when it is possible to avoid this problem, the beam itself can experience vibration (and particularly so upon removing the electrostatic force in order to conserve energy). Such vibration can impact the accuracy and/or effective speed of the optical switch itself, as such vibration can readily impart incorrect momentary placement of a reflected optical beam.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein.
USPTO Backgrounds
USPTO Backgrounds