Vibration sensor employing a flexible diaphragm and an electret film
First Claim
1. A vibration sensor for use in a navigation apparatus comprising:
- a substrate;
a circular diaphragm from which are integrally formed a diaphragm portion, a supporting portion and an plurality of flexible displacement portions for coupling said diaphragm portion and said supporting portion such that said diaphragm portion is able to move relative to said substrate, wherein said plurality of flexible displacement portions define therebetween a plurality of openings in said diaphragm which are sized and arranged to decrease said diaphragm'"'"'s responsiveness to sound vibrations;
an electret film disposed either on said substrate on opposite said diaphragm or on said diaphragm opposite said substrate; and
a holder for holding said substrate and said supporting portion of said diaphragm in such a manner that said diaphragm portion comes close to or away from said substrate in parallel.
0 Assignments
0 Petitions
Accused Products
Abstract
A vibration sensor includes a substrate (5), a plate-like diaphragm (3) forming a capacitor, and holding means (2), (4), (6) for holding the diaphragm so as to be movable in parallel to the substrate. The diaphragm includes a plurality of flexible displacement portions (3c), (3d) for enabling the supporting portion of the diaphragm to be movable in parallel to the substrate. When vibrations are applied to the vibration sensor, the diaphragm portion of the diaphragm is vibrated and electrostatic capacity formed between the substrate and the diaphragm is changed based on the vibrations. Vibrations are detected on the basis of the change of electrostatic capacity. Since the vibration sensor includes the flexible displacement portions, the diaphragm becomes difficult to be vibrated due to a sound pressure and a vibration detected output can be prevented from being disturbed by the sound pressure.
-
Citations
19 Claims
-
1. A vibration sensor for use in a navigation apparatus comprising:
-
a substrate; a circular diaphragm from which are integrally formed a diaphragm portion, a supporting portion and an plurality of flexible displacement portions for coupling said diaphragm portion and said supporting portion such that said diaphragm portion is able to move relative to said substrate, wherein said plurality of flexible displacement portions define therebetween a plurality of openings in said diaphragm which are sized and arranged to decrease said diaphragm'"'"'s responsiveness to sound vibrations; an electret film disposed either on said substrate on opposite said diaphragm or on said diaphragm opposite said substrate; and a holder for holding said substrate and said supporting portion of said diaphragm in such a manner that said diaphragm portion comes close to or away from said substrate in parallel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
Specification