Patent ID: RE40347

Claim:
An acceleration sensor comprising: a first substrate formed of a silicon material which is used as a conductive material; a second substrate provided on the lower side of said first substrate and electrically insulated from the first substrate; said first substrate including: a support beam having a mass portion forming capacitive electrodes for displacement in a parallel direction to a surface of said second substrate according to the degree of acceleration, a fixed portion for fixing said support beam to said second substrate and a support portion for intermediately supporting said mass portion to said fixed portion, an insulating groove extending through a thickness of said first substrate around the entire periphery of said support beam, and stationary blocks forming capacitive electrodes defined by said insulating groove on the outer sides of said support beam separately across said insulating groove and fixed to said second substrate; and gap means forming a gap space in order to space said mass portion and said supporting portion from a surface of said second substrate; and said second substrate being separated from said first substrate by an insulating layer which is at least provided on the lower side of said fixed portion and stationary blocks.