| CPC H03H 9/215 (2013.01) [G01C 19/5628 (2013.01); G01P 15/097 (2013.01)] | 12 Claims |

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1. A structure of a quartz crystal substrate having a slit penetrating both main surfaces of the quartz crystal substrate and having one closed end in a longitudinal direction of the slit, which is a first direction along the main surfaces, the structure comprising:
as an inner wall of the slit,
a first side surface extending along the first direction;
a second side surface extending along the first direction;
a first end surface being part of the closed end, continuous with the first side surface, having a different orientation from the first side surface, and extending along a first crystal plane of the quartz crystal substrate; and
a second end surface being part of the closed end, continuous with the second side surface, having a different orientation from the second side surface, and extending along a second crystal plane of the quartz crystal substrate, wherein
in a plan view of the quartz crystal substrate viewed perpendicular to the main surfaces, an intersection point where a first straight line corresponding to the first end surface and a second straight line corresponding to the second end surface intersect each other is located inside the quartz crystal substrate.
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