Latching microaccelerometer
First Claim
1. A microaccelerometer device for indicating an acceleration event comprising:
- a substrate having a surface plane;
a first cantilever formed from a material layer deposited on said substrate and having a fixed end and a free end, the fixed end being anchored to said substrate, said first cantilever having a mass affixed thereto;
latch means formed from a material layer deposited on said substrate for unlatching said first cantilever in a first position thereof and, for latching said first cantilever when the free end of said first cantilever has moved to a predetermined position, to indicate an occurrence of an acceleration event;
conductor means coupled between said latch means and said first cantilever for enabling dispatch therefrom of a signal indication of a latched state or an unlatched state of said first cantilever; and
stop means positioned to confront said mass for controlling unwanted movement of said first cantilever in a direction opposite to a direction of the movement being read out.
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Accused Products
Abstract
A surface micromachined microaccelerometer includes a substrate which has a surface plane, and a cantilever formed on the substrate with a fixed end and a free end, the fixed end being anchored to the substrate. The cantilever includes a mass fixed along the length of the cantilever. A cooperating device reads out the occurrence of an acceleration event when the free end of the cantilever has moved to a predetermined position. The cooperating device may be fixed or an opposing co-aligned cantilever structure. In a first embodiment, the cooperating device takes the form of a fixed structure having slots in which the tip of the cantilever is selectively retained. A further embodiment configures the cooperating device as an overlapping opposed cantilever. A further feature of the invention enables a reset function of a latched cantilever and comprises a pair of layers which when energized cause a cantilever to be suitably deflected so as to return from the latched state back to the unlatched state.
66 Citations
17 Claims
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1. A microaccelerometer device for indicating an acceleration event comprising:
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a substrate having a surface plane; a first cantilever formed from a material layer deposited on said substrate and having a fixed end and a free end, the fixed end being anchored to said substrate, said first cantilever having a mass affixed thereto; latch means formed from a material layer deposited on said substrate for unlatching said first cantilever in a first position thereof and, for latching said first cantilever when the free end of said first cantilever has moved to a predetermined position, to indicate an occurrence of an acceleration event; conductor means coupled between said latch means and said first cantilever for enabling dispatch therefrom of a signal indication of a latched state or an unlatched state of said first cantilever; and stop means positioned to confront said mass for controlling unwanted movement of said first cantilever in a direction opposite to a direction of the movement being read out. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A microaccelerometer device for indicating an acceleration event comprising:
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a substrate having a surface plane; a cantilever formed from a material layer on said substrate and having a fixed end and a free end, the fixed end being anchored to said substrate; actuating means for moving said cantilever responsive to an acceleration event such that said cantilever bends transversely out of said surface plane of said substrate; latch means formed from a material layer deposited on said substrate for latching the free end of said cantilever prior to occurrence of an acceleration event, said latch means configured as a fixed structure having a body portion and projection therefrom defining at least one notch in which the free end of the cantilever can be retained; and means for reading out the occurrence of an acceleration event when the free end of said cantilever has moved to an unlatched position. - View Dependent Claims (16, 17)
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Specification