Electrical connectors – Preformed panel circuit arrangement – e.g. – pcb – icm – dip,... – Distinct contact secured to panel circuit
Reexamination Certificate
2001-04-25
2001-10-09
Donovan, Lincoln (Department: 2832)
Electrical connectors
Preformed panel circuit arrangement, e.g., pcb, icm, dip,...
Distinct contact secured to panel circuit
C439S852000, C439S856000, C439S082000, C200S181000, C438S050000, C438S052000
Reexamination Certificate
active
06299462
ABSTRACT:
FIELD OF THE INVENTION
This invention generally relates to photolithographically patterned springs for use in self-assembling micro-electromechanical systems (MEMS) structures.
BACKGROUND OF THE INVENTION
A process has been developed which allows for the photolithographically patterning a spring formed on a substrate. An inherent stress gradient in the spring causes a free portion of the spring to bend up and away from the substrate.
Photolithographically generated springs have a variety of uses including providing electrical contact between separate connection pads onto devices. Particularly, the spring is patterned as a spring contact where the anchor portion fixed to the substrate is electrically connected to a first contact pad on the substrate. The free portion compliantly contacts a second contact pad, thereby electrically interconnecting the two contact pads. Thus, in the foregoing the concept of moving a portion of a micro-machined structure out of a plane is used for improving electrical contact between devices.
Another implementation of a structure, which motivates a portion of a micro-machined structure out of a plane of the substrate, is a two-port reflective switch. Such a switch consists of a moveable shutter connected to an electrostatic out-of-plane actuator capable of inserting the shutter in the light path between two optical fibers.
SUMMARY OF THE INVENTION
A MEMS structure is provided including a substrate. Within the substrate is deposited a spring comprising of material initially fixed to the substrate along a length of the spring. The material forming the spring has an inherent stress gradient when initially fixed to the substrate. A non-stressed constraint plate is deposited on the substrate opposite the spring. The non-stressed constraint plate has a minimal inherent stress gradient. A hinged member has a first portion connected to the spring, and a second portion connected to the non-stressed constraint plate. A constraint mechanism is formed on the substrate such that at least a portion of the constraint plate is in control of the control mechanism. When at least a free portion of the spring and the constraint plate are released from the substrate, while an anchor portion of the spring remains fixed to the substrate, the inherent stress gradient of the spring biases the free portion of the spring away from the substrate. This occurs until the constraint mechanism constrains the spring from further movement.
With attention to another aspect of the present invention, the MEMS structure is self-assembling, in that as the spring biases the free portion away from the substrate, the constraint mechanism will fix the angle of the MEMS structure to a predetermined angle from the substrate surface.
With attention to yet another aspect of the present invention, a mirror is deposited on a surface of the free portion of the spring, or attached to the constraint member, such that the mirror may be positioned at a predetermined fixed angle.
With attention to yet another aspect of the present invention, the MEMS structure is self-assembling upon initial release, in the sense that it moves to the predetermined angle without a further motivating force. The MEMS structure is also collapsible and repeatedly self-assembling to the predetermined angle.
REFERENCES:
patent: 3842189 (1974-10-01), Southgate
patent: 5302145 (1994-04-01), Spinnato et al.
patent: 5613861 (1997-03-01), Smith et al.
patent: 5848685 (1998-12-01), Smith et al.
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patent: 6079988 (2000-06-01), Hashiguchi et al.
patent: 6137623 (2000-10-01), Robertson et al
Low Insertion Loss Packaged and Fiber-Connectorized Si Surface-Micromachined Reflective Optical Switch, (Aksyuk et al.) Solid-State and Actuator Workshop, Hilton Head Island, SC, Jun. 1998.
Donovan Lincoln
Fay Sharpe Fagan Minnich & McKee LLP
Lee Kyung S.
Xerox Corporation
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