A sensor for a seismic reflection survey to explore for oil or natural gas excites an artificial earthquake and grasps reflected waves of seismic waves thereof reflected on a stratum as acceleration, after multiple sensors are scattered and disposed to become a predetermined two-dimensional array, on aground surface of the stratum in which resources are predicted to be buried. The sensor for the seismic reflection survey is used to analyze acceleration data received all at once by a group of sensors disposed two-dimensionally, check a state of the stratum, and determine presence or absence of the resources such as the oil and the natural gas. An acceleration sensor for the sensor for the seismic reflection survey is requested to realize both a low noise characteristic enabling detection of an acceleration signal having an extraordinarily low noise as compared with sensors of other fields and low consumption power necessary for controlling multiple sensors at the same time.
An acceleration sensor manufactured using MEMS technology can be miniaturized dramatically as compared with the conventional acceleration sensor and is expected as a solution to realize the above request.
PTL 1 and PTL 2 disclose an MEMS capacitive acceleration sensor that has a structure in which an MEMS capacitive element is used commonly for signal detection and for application of servo force to generate force in a direction reverse to a detection signal and an area is reduced. In this structure, a method of performing signal detection and servo control alternately is used in time-division processing to use the MEMS capacitive element commonly. In the time-division processing, a method of including resetting between the signal detection and the servo control is also used.
USPTO Backgrounds
USPTO Backgrounds