Vibration analyzing device
First Claim
1. A vibration analyzing device comprising:
- a semiconductor substrate;
a vibrator having a vibratable portion, which is generally in the form of a thin plate and comprises a unitary electrode layer, and at least one base portion which is contiguous to said vibratable portion and fixed to said substrate such that said vibratable portion is spaced from said substrate and extends generally parallel to said substrate;
a fixed electrode layer formed in a surface region of said substrate so as to lie opposite to said vibratable portion of said vibrator such that said electrode layer of said vibrator and said fixed electrode layer provide a variable capacitor; and
an electric circuit means integrated with said substrate for detecting a change in the capacitance of said variable capacitor.
1 Assignment
0 Petitions
Accused Products
Abstract
A microelectronic device to detect mechanical vibrations and analyze vibration frequencies. The device comprises a vibrator in the form of thin plate supported on a semiconductor substrate in the manner of either cantilever beam or fixed beam. The vibrator is either conductive or coated with a conductive film to serve as a vibratable electrode layer. The substrate is formed with a fixed electrode layer in an area opposite to the vibrator, and an electric circuit to detect a change in the capacitance between the fixed and vibratable electrode layers is integrated with the substrate. For discrimination of vibration frequencies without using any bandpass filter, the device may have a plurality of vibrators different in resonance frequency each paired with a fixed electrode layer. To make the device sharply responsive to specific frequencies within a very narrow range, two vibrators slightly different in resonance frequency are arranged close to each other, and changes in the capacitances of two variable capacitors respectively provided by the two vibrators are detected combinedly.
-
Citations
28 Claims
-
1. A vibration analyzing device comprising:
-
a semiconductor substrate; a vibrator having a vibratable portion, which is generally in the form of a thin plate and comprises a unitary electrode layer, and at least one base portion which is contiguous to said vibratable portion and fixed to said substrate such that said vibratable portion is spaced from said substrate and extends generally parallel to said substrate; a fixed electrode layer formed in a surface region of said substrate so as to lie opposite to said vibratable portion of said vibrator such that said electrode layer of said vibrator and said fixed electrode layer provide a variable capacitor; and an electric circuit means integrated with said substrate for detecting a change in the capacitance of said variable capacitor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
-
Specification