Electrical transmission or interconnection systems – Switching systems
Patent
1998-08-24
2000-05-16
Gaffin, Jeffrey
Electrical transmission or interconnection systems
Switching systems
307125, H01H 104, H02B 124
Patent
active
060641266
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION
This invention relates to switches of the kind including two terminals, a plurality of conductive tracks extending from each terminal, the conductive tracks connected with one terminal being electrically insulated from the tracks connected with the other terminal, the switch including a plurality of electrically-conductive bridging elements spaced from the tracks and displaceable between a first position where the bridging elements are spaced from the tracks and a second position where each bridging elements is in contact with a track connected with one terminal and a track connected with the other terminal such that current can flow in parallel between the two terminals via the conductive tracks and the bridging elements, and an actuator arranged to displace the bridging elements between the first and second position.
The switching of high currents is usually carried out by means of an electromagnetic relay or contactor employing a solenoid to displace an armature so that it bridges or isolates two contacts, thereby allowing or preventing current flow between the terminals. These relays can operate reliably but require relatively high currents to operate the solenoid. They are also bulky and heavy, and respond relatively slowly because of the mass of the armature. Lower currents can be switched using semiconductor devices such as FETs and thyristors but these have the disadvantage of introducing a voltage drop across the device and of not being suitable for higher current operation. U.S. Pat. No. 5,430,597 describes a current interrupting device of the above-specified kind having parallel branches extending from input and output lines, which are bridged by a number of micromechanical switches.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved form of switch.
According to one aspect of the present invention there is provided a switch of the above-specified kind. At least some of the bridging elements are formed in a common plate of material that is fixed and is formed to provide flexible elements by which the bridging elements are supported in the plate, such that each bridging element is independently flexible relative to the plate and failure of one bridging element in the second position does not prevent other bridging elements moving to the first position.
The upper surface of each track and the lower surface of each bridging element is preferably flat, the bridging elements in the lower position contacting the tracks across their entire width. The plate may be of silicon, the bridging elements having an electrically-conductive layer arranged to contact the tracks when the bridging elements are displaced to their second position. The bridging elements may be of rectangular shape, the flexible elements being a pair of flexure elements extending outwardly of each bridging element on opposite sides midway along its length. The actuator is preferable an electrostatic actuator. The conductive tracks and bridging elements are preferably located in an evacuated housing. The conductive tracks may extend on a silicon substrate. The conductive tracks may extend on a layer of diamond, the layer of diamond extending on a substrate of a different material.
According to another aspect of the present invention there is provided a switching system including a first switch according to the above aspect of the invention and a second semiconductor switch connected in series with the first switch.
BRIEF DESCRIPTION OF THE DRAWINGS
A switch and a system including a switch according to the present invention, will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a plan view showing a lower wafer of the switch and the location of the bridging elements of the switch;
FIG. 2 is a cross-sectional transverse view of a part of the switch to an enlarged scale;
FIG. 3 is a plan view of a central wafer of the switch; and
FIG. 4 is a schematic diagram of a system including the switch.
REFERENCES:
patent: 5479042 (1995-12-01), James et al.
patent: 5619061 (1997-04-01), Goldsmith et al.
patent: 5637904 (1997-06-01), Zettler
patent: 5794761 (1998-08-01), Renaud et al.
Gaffin Jeffrey
Zura Peter
LandOfFree
Switches and switching systems does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Switches and switching systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Switches and switching systems will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-260886