The present application is based on, and claims priority from JP Application Serial Number 2018-140030, filed Jul. 26, 2018, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a physical quantity sensor, an electronic apparatus, and a vehicle.

2. Related Art

Recently, a physical quantity sensor manufactured using the MEMS (micro-electromechanical systems) technology has been developed. As such a physical quantity sensor, for example, US2015/085901A1 discloses an electrostatic capacitance-type acceleration sensor which has a functional element having a moving electrode (finger electrode) and a fixed electrode (detection electrode) arranged facing each other in a comb-like form, in which the space between the moving electrode and the fixed electrode changes when an acceleration (physical quantity) is applied to the moving electrode, and which detects the acceleration based on the electrostatic capacitance between these two electrodes. In this acceleration sensor, in order to eliminate the influence of a stress caused by warping or the like due to temperature change of a substrate to which the functional element is fixed, a part of the fixed electrode is formed as a correction electrode and a stress applied to the substrate is detected as a change in the electrostatic capacitance between the moving electrode and the correction electrode. Thus, the influence of the stress applied to the substrate is corrected and detection accuracy is increased.

However, in the physical quantity sensor disclosed in US2015/085901A1, the position of a anchor part where the moving electrode is fixed to the substrate and the position of a anchor part where the fixed electrode (detection electrode and correction electrode) is fixed to the substrate are spaced apart from each other. This results in a large amount of displacement in the warping of the substrate due to temperature change. Therefore, a large correction error occurs in correcting the influence of the warping of the substrate, posing the problem of reduced detection accuracy for the physical quantity applied to the physical quantity sensor.

SUMMARY

A physical quantity sensor according to an aspect of the disclosure includes: a substrate; a correction electrode fixed to the substrate; a detection electrode fixed to the substrate; and a moving member fixed to the substrate. The moving member has: a base part; a first anchor part fixed to the substrate; a first finger electrode extending from the base part and facing the correction electrode; a mass part coupled to the base part via an elastic part, arranged at an opposite side of the correction electrode from the base part, and provided in such a way as to be displaceable in a direction of detection of a physical quantity in relation to the substrate; and a second finger electrode extending from the mass part and facing the detection electrode. A distance between a second anchor part where the detection electrode and the substrate are fixed, and the base part, is shorter than a distance between the second anchor part and the mass part.

In the physical quantity sensor, a distance between a third anchor part where the correction electrode and the substrate are fixed, and the base part, may be shorter than a distance between the third anchor part and the mass part.

In the physical quantity sensor, a distance between a third anchor part where the correction electrode and the substrate are fixed, and the base part, may be longer than a distance between the third anchor part and the mass part.

In the physical quantity sensor, the mass part may be spaced apart from the substrate.

In the physical quantity sensor, the correction electrode and the detection electrode may respectively have a rectangular shape.

In the physical quantity sensor, the correction electrode may have a protrusion protruding to a side opposite to a side facing the first finger electrode. The detection electrode may have a protrusion protruding to a side opposite to a side facing the second finger electrode.

In the physical quantity sensor, the correction electrode may have a first correction electrode and a second correction electrode. The detection electrode may have a first detection electrode and a second detection electrode. The first correction electrode and the second detection electrode may be arranged in line symmetry about an axis in the direction of detection.

In the physical quantity sensor, the first correction electrode and the second correction electrode may be arranged in point symmetry about a center of gravity of the moving member.

An electronic apparatus according to another aspect of the disclosure includes: the foregoing physical quantity sensor; and a control unit performing control based on a detection signal outputted from the physical quantity sensor.

A vehicle according to still another aspect of the disclosure includes: the foregoing physical quantity sensor; and a control unit performing control based on a detection signal outputted from the physical quantity sensor.

