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US 4,724,351 AGranted
Double resonating beam force transducer with reduced longitudinal pumping
AssigneeQuartex, Inc.
InventorsErrol P. EerNisse, Walter P. Kistler
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AssigneeQuartex, Inc.
InventorsErrol P. EerNisse, Walter P. Kistler
Estimating the term…
A double resonator beam force transducer configured to minimize longitudinal pumping by making the beams vibrate symmetrically. This can be accomplished by making the boundary conditions of the beams symmetrical or, if the boundary conditions are nonsymmetric, then by biasing the beams inwardly or outwardly to compensate for the nonsymmetrical boundary conditions of the beams. In the nonsymmetrical case where the beams would bow outwardly at their fundamental resonant frequency or an odd overtone thereof, an inward bias is provided to minimize longitudinal pumping. In the nonsymmetrical case where the beams would bow inwardly at an even overtone of the fundamental resonant frequency, an outward bias is provided to minimize longitudinal pumping. The inward or outward bias is provided in various embodiments by bowing the beams inwardly or outwardly, placing masses on the inner or outer edges of the beams, or tapering the inner or outer edges of the beams so that the width of the beams increase toward their midpoints.
A double-beam resonator having reduced longitudinal pumping, comprising a pair of generally parallel, spaced-apart beams of substantially equal length extending between a pair of supports and including means for causing said beams to resonate in opposite lateral directions, said supports having a lateral dimension that is greater than the distance between the outer edges of said beams so that at least a portion of said supports extend laterally beyond the outer edges of said beams, said supports extending from respective mounting pads having a lateral dimension that is greater than the lateral dimension of said supports such that said mounting pads extend laterally beyond the outer edges of said supports, said supports providing inward restoring forces to said beams to cause said beams to resonate inwardly and outwardly in substantially equal amounts about mean positions that are substantially straight, thereby minimizing the lateral deviation of said beams from said mean position in order to minimize the longitudinal pumping of said beams.
A double-beam resonator having reduced longitudinal pumping, comprising a pair of generally parallel beams of substantially equal length extending between a pair of mounting pads and including means for causing said beams to resonate in opposite lateral directions, said beams bowing inwardly toward each other at their midpoints to cause said beams to resonate inwardly and outwardly in substantially equal amounts about mean positions that are substantially straight, thereby minmizing the lateral deviation of said beams from said mean position in order to minimize the longitudinal pumping of said beams.
A double-beam resonator having reduced longitudinal pumping, comprising a pair of generally parallel beams of substantially equal length extending between a pair of mounting pads and including means for causing said beams to resonate in opposite lateral directions, said beams bowing outwardly away from each other at their midpoints to cause said beams to resonate inwardly and outwardly in substantially equal amounts about mean positions that are substantially straight, thereby minimizing the lateral deviation of said beams from said mean position in order to minimize the longitudinal pumping of said beams.
A double-beam resonator having reduced longitudinal pumping, comprising a pair of generally parallel beams of substantially equal length extending between a pair of mounting pads and including means for causing said beams to resonate in opposite lateral directions, said beams each carrying a mass at its midpoint along one lateral edge thereof to cause said beams to resonate inwardly and outwardly in substantially equal amounts about mean positions that are substantially straight, thereby minimizing the lateral deviation of said beams from said mean position in order to minimize the longitudinal pumping of said beams.
A double-beam resonator having reduced longitudinal pumping, comprising a pair of generally parallel beams of substantially equal length extending between a pair of mounting pads and including means for causing said beams to resonate in opposite lateral directions, the width of each beam becoming greater toward the midpoint thereof to cause said beams to resonate inwardly and outwardly in substantially equal amounts about mean positions that are substantially straight, thereby minimizing the lateral deviation of said beams from said mean position in order to minimize the longitudinal pumping of said beams.
A double-beam resonator having reduced longitudinal pumping, comprising a pair of generally parallel beams of substantially equal length extending between a pair of mounting pads and including means for causing said beams to resonate in opposite lateral directions, each of said mounting pads extending laterally beyond the outer edges of said beams a distance approximately equal to half the lateral distance between said beams to increase the inward restoring force exerted on said beams by said mounting pads to offset the outward restoring force exerted on said beams by said mounting pads, thereby causing said beams to resonate inwardly and outwardly in substantially equal amounts about mean positions that are substantially straight in order to minimize the longitudinal pumping of said beams.
A double-beam resonator having reduced longitudinal pumping, comprising a pair of generally parallel beams of substantially equal length extending between a pair of mounting pads and including means for causing said beams to resonate in opposite lateral directions, the outer edges of said beams tapering outwardly as they join said mounting pads to provide inward restoring forces to said beams to offset the outward restoring forces applied to said beams by said mounting pads, thereby causing said beams to resonate inwardly and outwardly in substantially equal amounts about mean positions that are substantially straight in order to minimize the longitudinal pumping of said beams.
A double-beam resonator having reduced longitudinal pumping, comprising a pair of generally parallel beams of substantially equal length extending between a pair of mounting pads and including means for causing said beams to resonate in opposite lateral directions, the inside edge of each of said beams having formed therein a notch at each end thereof to reduce the outward restoring force exerted on said beams by said mounting pads, thereby causing said beams to resonate inwardly and outwardly in substantially equal amounts about mean positions that are substantially straight in order to minimize the longitudinal pumping of said beams.
A force transducer, comprising:
A force transducer, comprising:
A force transducer, comprising:
A force transducer, comprising:
In a double resonating beam force transducer having a pair of beams connected between a pair of mounting pads, a method of minimizing the longitudinal pumping produced by said beams, comprising biasing said beams in directions opposite to the mean positions that said beams would otherwise assume when resonating at the fundamental resonant frequency of said beams or an overtone thereof.
In a quartz crystal microresonator of the type including first and second stem portions, a pair of integral tines extending between said stem portions, a slot between said tines, said slot having opposed crotches where said tines join said stem portions, and a plurality of electrodes mounted on each so said tines, spaced along the length thereof, said electrodes being adapted for receipt of an AC voltage for causing said tines to oscillate, the improvement wherein each of said tines has a pair of opposed shoulders where said tines join said stem portions and wherein the widths of said shoulders at said opposite ends of said tines are approximately equal and approximately equal to one-half of the width of said crotches.
A double-beam resonator having reduced longitudinal pumping, comprising a pair of generally parallel, spaced-apart beams of substantially equal length extending between a pair of mounting pads and including means for causing said beams to resonate in opposite lateral directions, said mounting pads having lateral dimensions substantially equal to the sum of the lateral distance between the outer edges of said beams and the lateral distance between the inner edges of said beams such that said mounting pads extend laterally beyond the edges of said beams by a distance of approximately one-half the lateral distance between the inner edges of said beams.
A double-beam resonator having reduced longitudinal pumping, comprising a pair of generally parallel, spacedapart beams of substantially equal length extending between a pair of mounting pads and including means for causing said beams to resonate in opposite lateral directions, said mounting pads having lateral dimensions that are greater than the lateral distance between the outer edges of said beams so that at least a portion of said mounting pads extends laterally beyond the outer edges of said beams, the side edges of said mounting pads tapering inwardly to the outer edges of said beams.
Dependencies are inferred from the claim text.