Semiconductor accelerometer with damperless structure

A semiconductor accelerometer comprising:

• a proof mass;
• a beam for suspending said proof mass;
• a piezo resistor formed at an end part of said beam;
• and
• a thin part disposed continuously to said end part of said beam on which said piezo resistor is provided, said thin part being the same in thickness as and wider in width than said beam.

A semiconductor accelerometer comprising:

• four pieces of beams constituting a double cantilever suspension structure which two pairs are disposed in parallel with each other, each pair thereof being disposed in symmetry with each other with respect to the X and Y axes in the X-Y plane with three-dimensional space orthogonal axes of X, Y and Z;
• a proof mass suspended by said four pieces of beams in a space within a fixing frame;
• piezo resistors disposed on said beams of double cantilever suspension structure, four pieces of said piezo resistors being disposed on four pieces of said beams of double cantilever suspension structure at a rate of one piece of piezo resistor on one piece of beam and said piezo resistors being alternatingly disposed at end parts of the proof mass side and the fixing frame side of said beams of double cantilever suspension structure;
• and
• an output circuit including a Wheatstone bridge circuit constituted by connecting said piezo resistors disposed in adjacency to each other into a loop.

A semiconductor accelerometer of a damperless structure comprising:

• an accelerometer chip having a beam of a thin thickness, a movable mass of a thick thickness suspended by said beam and a means for detecting a movement of said mass to detect an applied acceleration, all of which are composed of semiconductor substance;
• and
• a case for housing and fixing said accelerometer chip therein;
• wherein said beam of said accelerometer chip has a dimension which makes a resonant frequency of said beam a certain value equal to or higher than a resonant frequency of said case.