Packaged microelectromechanical devices and systems

DETAILED DESCRIPTION Preferred implementations of the various aspects of the invention will now be described while referring to the figures, several of which may be simultaneously referred to during the course of the following description.
In FIG.
1, an illustrative assembly 11 according to the invention includes an approximately bell-shaped housing 13 closed at what would otherwise be the bell-opening end by MEMS chip 15 having an array of steerable mirrors and having a mounting flange 17.
The fit between housing 13 and flange 17 is adapted to facilitate a hermetic seal.
Preferably, the flange 17 is welded or brazed to the housing 13.
The housing 13 includes a plurality of ports.
A first one is the opening in which optical fiber bundle 19 is disposed.
A second one is the already-mentioned bell opening of the housing 13.
Third and fourth ports are openings in which infrared radiation windows 21 and 23 are mounted via suitable flanges 47 and 49 like flange 17.
Fifth and sixth ports are occupied by tube 25 for evacuating air and tube 27 for pressurizing with inert gas, such as argon with a trace of helium.
Tubes 25 and 27 are secured to housing 13 by flanges 43 and 45 that are welded or brazed to housing 13.
Static mirror 29 also appears in housing 13 but does not require a port because its function is purely internal.
It is bonded to the inner wall of the housing.
The material of housing 13 is illustratively 410 stainless steel but could also be Invar or some other material with an appropriate coefficient of expansion.
Flange 17 and the other flanges should also be of the same material.
MEMS chip 15 is a silicon semiconductor chip providing a suitable substrate for integrated MEMS elements including steerable mirror elements 31 and their associated integrated actuators (not shown), which may be of known type.
MEMS chip 15 is illustratively wire-bonded to a pin-grid array (PGA) 35.
PGA 35 has its own flange 16 that is seam-welded to flange 17 at seam weld 39.
Windows 21 and 23 should be of infrared-transmitting material, such as silica, sapphire, or quartz