Electricity: conductors and insulators – Boxes and housings – Hermetic sealed envelope type
Reexamination Certificate
1999-01-06
2001-05-08
Dinkins, Anthony (Department: 2831)
Electricity: conductors and insulators
Boxes and housings
Hermetic sealed envelope type
C174S050600, C174S050510, C174S050510, C174S050610, C257S699000, C257S708000
Reexamination Certificate
active
06229088
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to leak-free enclosures to support electronic device and more specifically to an enclosure construction that will allow a reduction in the overall height of the enclosure.
The electronics industry requires vast quantities of miniature enclosures to support and protect electronic crystals, transistors, and other devices. These enclosures consist of “bases” or “headers” and matching “cans” or “covers”. These enclosures provide protection from atmosphere, moisture, and other factors that can degrade their performance of electronic devices. The base supports and protects the active component or components in a hermetic or leak-free environment while providing a method for signals to pass into and out of the device by means of any number of insulated wires or pins. One of the most reliable and cost-effective methods of constructing bases or headers employs the use of certain glass and metal alloys that can be bonded to each other through the use of various processes. These processes produce a “finished” base that is ready to receive the active device.
After the active device is installed, a “can” or “cover” is attached over the base to complete the enclosure. There are various methods for attaching the cover which must also form a hermetic seal with the base. Methods typically employed are: Attachment by a relatively low temperature solder, resistance welding, and cold-welding.
Each of the “closure” methods have applications, but the cold-welding method has been found to be a preferred method, especially in the electronic frequency control industry, as it neither generates nor requires heat, current, flux, or other potentially detrimental factors.
The cold-weld method as commonly used in the frequency control industry was developed in the 1960's. The bases are designed around a metal stamping manufactured from copper-clad Kovar material. This material is typically 0.010″ thick and consists of a layer of 0.007″ Kovar physically bonded to a 0.003″ layer of copper. The Kovar alloy is a preferred material to bond to the glass employed, while the copper layer provides the properties required for a reliable cold-weld seal to the cover.
Cold-weldable bases for the electronics industry in general, and the frequency-control industry in particular, have been manufactured for over thirty years. These bases (Military types HC-35, 37, 42, and 43 for example) are 0.100″ high. This height is necessary to provide a thickness of glass sufficient to effect a hermetic seal while providing a decoupling area in proximity to a flange where the cold-weld is effected. This decoupling area is intended to allow the movement of metal that occurs when the base and cover are cold-welded. Without this glass-free decoupling area, mechanical stresses from the cold-welding operation would crack and destroy or compromise the hermeticity of the completed component.
Applicant is aware of the following U.S. Pat. Nos.: 2,444,312; 2,976,465; 3,184,534; 3,419,763; 3,546,363; 3,726,987; 3,816,847; 4,706,106; 5,206,460; and, 5,367,124.
SUMMARY OF THE INVENTION
The necessity of this decoupling area requires the base to be almost twice the thickness that otherwise would be required. Due to the constant pressures in the electronics industry for smaller components, a reduction in the height of the base which allows the use of a shorter cover offers significant advantages.
The present invention utilizes two separate metal stampings rather than one which is now common. The top stamping is virtually identical to the currently used stamping except that it is approximately 0.060″ high rather than the current 0.1001″ height. The unique feature is a flanged Kovar inner ring which is welded into the underside of the first stamping. Glass is bonded to the Kovar surfaces of both stampings, ensuring a hermetic seal while providing a suitable decoupling area sufficient to withstand the stresses associated with the subsequent cold-welding closure method. Glass thickness at critical areas remains equal to, or greater than, current designs to preserve or surpass currently achievable hermeticity levels, but with a package 50-60% of the height of current designs, and with no increase in the “footprint” size of the device.
It is an object of this invention to reduce the height of the base while retaining the necessary height to provide an adequate decoupling area and at the same time, retaining adequate glass thickness to preserve hermetically.
It is another object of the present invention to provide a low profile electronic enclosure that is simple in construction, economical to manufacture and simple and efficient to use.
With the above and other objects in view, the present invention consists of the combination and arrangement of parts hereinafter more fully described, illustrated in the accompanying drawing and more particularly pointed out in the appended claims, it being understood that changes may be made in the form, size, proportions and minor details of construction without departing from the spirit or sacrificing any of the advantages of the invention.
REFERENCES:
patent: 2444312 (1948-06-01), Roberds
patent: 2976465 (1961-03-01), Jensen
patent: 3184534 (1965-05-01), Jensen
patent: 3419763 (1968-12-01), Beaudouin
patent: 3546363 (1970-12-01), Pryor
patent: 3726987 (1973-04-01), Pryor et al.
patent: 3816847 (1974-06-01), Nagao
patent: 3857993 (1974-12-01), Gregory
patent: 4706106 (1987-11-01), Shiba et al.
patent: 5206460 (1993-04-01), Yang
patent: 5367124 (1994-11-01), Hoffman et al.
Dinkins Anthony
Legacy Technologies, Inc.
Lovercheck and Lovercheck
Ngo Hung V
LandOfFree
Low profile electronic enclosure does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Low profile electronic enclosure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low profile electronic enclosure will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2545284