Piezoelectric resonator and manufacturing method therefor
View Patent ↗A piezoelectric resonator includes a piezoelectric resonator element having a base portion and a resonating arm extending from the base portion, a package including a bottom to which the piezoelectric resonator element is fixed and a frame wall that surrounds the bottom and having an opening above the bottom, and a lid for closing the opening of the package. In this piezoelectric resonator, the lid includes a main body having a through-hole formed therein, a flange formed to surround a periphery of the main body and to be thinner than the main body, and an optically transparent member located in the through-hole. The flange has a joining portion with an upper end surface of the frame wall, and the main body projects in a direction from the flange to the bottom in a thickness direction. Also, the through-hole is at a position displaced in a first direction approaching a first end of the main body from a center of the main body. Also, the flange is joined with the frame wall such that a clearance between the first end and the joining portion of the flange nearest to the first end is larger than a clearance between a second end in a second direction opposite to the first direction of the main body and the joining portion of the flange nearest to the second end.
1. A piezoelectric resonator, comprising:
a piezoelectric resonator element having a base portion and a resonating arm extending from the base portion;
a package including a bottom to which the piezoelectric resonator element is fixed and a frame wall that surrounds the bottom and having an opening above the bottom; and
a lid for closing the opening of the package, the lid including:
a main body having a through-hole formed therein;
a flange formed to surround a periphery of the main body and to be thinner than the main body; and
an optically transparent member located in the through-hole, wherein:
the flange has a joining portion with an upper end surface of the frame wall; the main body projects in a direction from the flange to the bottom in a thickness direction;
the through-hole is at a position displaced in a first direction approaching a first end of the main body from a center of the main body; and
the flange is joined with the frame wall such that a clearance between the first end and the joining portion of the flange nearest to the first end is larger than a clearance between a second end in a second direction opposite to the first direction of the main body and the joining portion of the flange nearest to the second end.
2. The piezoelectric resonator according to claim 1 , wherein the flange has a width in the first direction larger than a width in the second direction.
3. The piezoelectric resonator according to claim 1 , wherein:
the lid includes a flange surface facing the package of the flange, a main body surface facing the package of the main body, and a connection surface connecting the flange surface with the main body surface; and
the connection surface has a concave curved surface.
4. The piezoelectric resonator according to claim 3 , wherein:
the connection surface includes a first connection portion connecting to a margin of the main body surface, a second connection portion connecting to the flange surface, and an intermediate portion between the first and second connection portions;
at least the intermediate portion is the concave curved surface; and
at least part of the connection surface is in contact with the frame wall.
5. The piezoelectric resonator according to claim 4 , wherein the first connection portion is connected perpendicularly to the main body surface.
6. The piezoelectric resonator according to claim 4 , wherein the intermediate portion is in contact with the frame wall.
7. The piezoelectric resonator according to claim 4 , wherein:
the intermediate portion is depressed from a margin of the main body surface; and
the first connection portion is in contact with the frame wall and a space is present between the intermediate portion and the frame wall.