Optical: systems and elements – Deflection using a moving element – By moving a reflective element
Reexamination Certificate
2002-03-12
2003-12-16
Robinson, Mark A. (Department: 2872)
Optical: systems and elements
Deflection using a moving element
By moving a reflective element
C359S298000, C310S309000
Reexamination Certificate
active
06665104
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to the field of microelectromechanical systems and, more particularly, to a microelectromechanical system that constrains the direction of forces acting on a load in a manner such that there is also a reduced potential for rubbing or contact between different portions of the system.
BACKGROUND OF THE INVENTION
There are a number of microfabrication technologies that have been utilized for making microstructures (e.g., micromechanical devices, microelectromechanical devices) by what may be characterized as micromachining, including LIGA (Lithographie, Galvonoformung, Abformung), SLIGA (sacrificial LIGA), bulk micromachining, surface micromachining, micro electrodischarge machining (EDM), laser micromachining, 3-D stereolithography, and other techniques. Bulk micromachining has been utilized for making relatively simple micromechanical structures. Bulk micromachining generally entails cutting or machining a bulk substrate using an appropriate etchant (e.g., using liquid crystal-plane selective etchants; using deep reactive ion etching techniques). Another micromachining technique that allows for the formation of significantly more complex microstructures is surface micromachining. Surface micromachining generally entails depositing alternate layers of structural material and sacrificial material using an appropriate substrate which functions as the foundation for the resulting microstructure. Various patterning operations (collectively including masking, etching, and mask removal operations) may be executed on one or more of these layers before the next layer is deposited so as to define the desired microstructure(s). After the microstructure(s) has been defined in this general manner, the various sacrificial layers are removed by exposing the microstructure(s) and the various sacrificial layers to one or more etchants. This is commonly called “releasing” the microstructure(s) from the substrate, typically to allow at least some degree of relative movement between the microstructure(s) and the substrate. The etchant is biased to the sacrificial material to remove the same at a greater rate than the structural material. Preferably, the microstructure(s) is released without allowing the etchant to have an adverse impact on the structural material of the microstructure(s).
Microelectromechanical systems are typically actuated in a manner where the direction of the load forces are substantially collinear with the motion of the actuator. However, for some actuation systems, the load may be permitted to move in a path that is not collinear with the motion of the actuator (e.g., where the load moves out of plane). Off-axis forces (i.e., non-collinear) can result that can be detrimental to the operation of the actuator. For instance, actuator electrodes may short together or portions of the actuator may contact other surfaces of the microelectromechanical system, thereby adversely impacting the motion of the actuator. It would be desirable for the portion the load force that is transmitted to the actuator to be constrained to be at least substantially collinear with the motion of the actuator, thereby facilitating the proper operation of the actuator. In other words, it would be desirable for off-axis components of the load force to be isolated from the actuator by a force isolation system of sorts, or equivalently, by some way of constraining the direction of the force acting on the actuator. For most applications, and particularly for applications involving precise positioning of optical elements, it would be further desirable to provide this force isolation function in a manner that does not exhibit hysteretic behavior. This generally means that it would be desirable for none of the surfaces of such a force isolation system to come into contact or rub during normal operation of the microelectromechanical system.
BRIEF SUMMARY OF THE INVENTION
A primary object of the present invention is to at least attempt to minimize off-axis forces of a load acting on a given microstructure, and do so in a way that does not produce rubbing or contacting surfaces. In one application of the present invention, the noted microstructure is an actuator. In this case, the present invention enables precise positioning of optical elements that involve out-of-plane motion, without exhibiting hysteretic behavior.
A first aspect of the present invention is embodied by a mirror positioning system that is fabricated using a substrate. The system includes a mirror that is interconnected with a portion of a first lever that is able to move relative to the substrate. The system further includes an actuator assembly that is interconnected with the substrate so as to be able to move relative thereto along a first path. A coupling assembly interconnects the actuator assembly with a portion of the first lever that is able to move relative to the substrate. Depending upon the direction that the actuator assembly moves along the first path, a first lever end either moves at least generally away from or toward the substrate, as will the portion of the mirror that is interconnected with the first lever. Movement of the actuator assembly and the resultant movement of the first lever end relative to the substrate exerts a force on the coupling assembly that is not collinear with the first path along with the actuator assembly moves. The mirror positioning system of the first aspect is configured to address this situation in at least two respects. One is that the mirror positioning system of the first aspect is configured to redirect the application of such a force to the actuator assembly so as to be at least generally collinear with the first path along which the actuator assembly moves relative to the substrate. Another is that the mirror positioning system of the first aspect is configured such that no portion of the coupling assembly is deflected by such a non-collinear force into contact with the substrate.
Various refinements exist of the features noted in relation to the subject first aspect of the present invention. Further features may also be incorporated in the subject first aspect of the present invention as well. These refinements and additional features may exist individually or in any combination. The mirror may provide any appropriate optical function, including without limitation to reflect an optical signal, to change the direction of an optical signal, to change the focus of an optical signal, to attenuate an optical signal, to diffract an optical signal, or any combination thereof. The mirror may be interconnected with the substrate in any appropriate manner, including without limitation directly by pivotally interconnecting the mirror with the substrate utilizing one or more compliant members, indirectly via the first lever, or a combination thereof (e.g., by interconnecting one or more portions of the mirror with the substrate with one or more compliant members or flexures, and also by interconnecting one or more other portions of the mirror with the first lever). “Pivotally interconnecting” or the like, as used herein, means any type of interconnection that allows a microstructure to at least generally undergo a pivoting or pivotal-like motion when exposed to an appropriate force, including without limitation any interconnection that allows a microstructure or a portion thereof to move at least generally about a certain axis. Representative pivotal interconnections include the use of a flexing or elastic deformation of a microstructure or a portion thereof, as well as the use of relative motion between two or more microstructures that are typically in interfacing relation during at least a portion of the relative movement (e.g., a hinge connection; a ball and socket connection).
The first lever may be interconnected with the substrate in any manner such that at least part of the first lever is able to move at least generally away from or toward the substrate. Whether at least part of the first lever moves at least generally away from or at
Barnes Stephen Matthew
McWhorter Paul Jackson
Miller Samuel Lee
Rodgers Murray Steven
Sniegowski Jeffry Joseph
Marsh & Fischmann & Breyfogle LLP
Memx, Inc.
Robinson Mark A.
LandOfFree
Mirror positioning assembly with vertical force component... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Mirror positioning assembly with vertical force component..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mirror positioning assembly with vertical force component... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3106691