Piezoelectric resonator unit and method for manufacturing the piezoelectric resonator unit

1. A piezoelectric resonator unit comprising:

a piezoelectric resonator;

a lid member and a base member defining an internal space that accommodates the piezoelectric resonator; and

a joining member joining the lid member and the base member,

wherein in a plan view of a principal surface of the base member, the joining member has a frame shape with a uniform width dimension surrounding the piezoelectric resonator,

wherein the frame shape is a rectangular shape including sides and corners, and in the plan view of the principal surface of the base member, a width dimension of the sides is equal to a width dimension of the corners,

wherein the corners each include a linear portion having a same width dimension as the sides in the plan view of the principal surface of the base member, a first curve connecting a first side of the sides to the linear portion, and a second curve connecting a second side of the sides to the linear portion;

the first curve and the second curve each include a first rounded portion having a first radius and a second rounded portion concentric with the first rounded portion and having a second radius different from the first radius; and

a difference between the first radius and the second radius is equal to the width dimension of the linear portion in the plan view of the principal surface of the base member.

2. The piezoelectric resonator unit according to Claim 1 , wherein the lid member and the joining member are each made of a metal material.

3. The piezoelectric resonator unit according to Claim 1 , wherein the corners each include a first rounded portion having a first radius and a second rounded portion concentric with the first rounded portion and having a second radius different from the first radius; and

in the plan view of the principal surface of the base member, a difference between the first radius and the second radius is equal to the width dimension of the sides.

4. The piezoelectric resonator unit according to claim 1 , wherein the base member includes respective grooves adjacent to each of the corners.

5. The piezoelectric resonator unit according to claim 1 , wherein the joining member includes:

a sealing frame in the frame shape on the principal surface of the base member and disposed along an entire circumference of the lid member; and

a joining material in the frame shape on the sealing frame.

6. The piezoelectric resonator unit according to claim 5 , wherein the frame shape is a rectangular shape including sides and corners; and

in the plan view of the principal surface of the base member, a width dimension of the sides is equal to a width dimension of the corners.

7. The piezoelectric resonator unit according to claim 6 , wherein the corners each include a first rounded portion having a first radius and a second rounded portion concentric with the first rounded portion and having a second radius different from the first radius; and

in the plan view of the principal surface of the base member, a difference between the first radius and the second radius is equal to the width dimension of the sides.

8. The piezoelectric resonator unit according to claim 6 , wherein the base member includes respective grooves adjacent to each of the corners.

9. A piezoelectric resonator unit comprising:

a piezoelectric resonator;

a lid member and a base member defining an internal space that accommodates the piezoelectric resonator; and

a joining member joining the lid member and the base member,

wherein in a plan view of a principal surface of the base member, the joining member has a frame shape with a uniform width dimension surrounding the piezoelectric resonator,

wherein the frame shape is a rectangular shape including sides and corners, and in the plan view of the principal surface of the base member, a width dimension of the sides is equal to a width dimension of the corners, and

wherein the base member includes respective anti-alloying films adjacent to each of the corners.

10. The piezoelectric resonator unit according to claim 9 , wherein the corners each include a first rounded portion having a first radius and a second rounded portion concentric with the first rounded portion and having a second radius different from the first radius; and

in the plan view of the principal surface of the base member, a difference between the first radius and the second radius is equal to the width dimension of the sides.

11. The piezoelectric resonator unit according to claim 9 , wherein the joining member includes:

a sealing frame in the frame shape on the principal surface of the base member and disposed along an entire circumference of the lid member; and

a joining material in the frame shape on the sealing frame.

12. The piezoelectric resonator unit according to claim 11 , wherein the frame shape is a rectangular shape including sides and corners; and

in the plan view of the principal surface of the base member, a width dimension of the sides is equal to a width dimension of the corners.

13. The piezoelectric resonator unit according to claim 12 , wherein the corners each include a first rounded portion having a first radius and a second rounded portion concentric with the first rounded portion and having a second radius different from the first radius; and

in the plan view of the principal surface of the base member, a difference between the first radius and the second radius is equal to the width dimension of the sides.

14. The piezoelectric resonator unit according to claim 12 , wherein the base member includes respective grooves adjacent to each of the corners.

15. The piezoelectric resonator unit according to claim 9 , wherein the lid member and the joining member are each made of a metal material.

16. A piezoelectric resonator unit comprising:

a piezoelectric resonator;

a lid member and a base member defining an internal space that accommodates the piezoelectric resonator; and

a joining member joining the lid member and the base member,

wherein in a plan view of a principal surface of the base member, the joining member has a frame shape with a uniform width dimension surrounding the piezoelectric resonator,

wherein the joining member includes:

a sealing frame in the frame shape on the principal surface of the base member and disposed along an entire circumference of the lid member; and

a joining material in the frame shape on the sealing frame,

wherein the frame shape is a rectangular shape including sides and corners, and in the plan view of the principal surface of the base member, a width dimension of the sides is equal to a width dimension of the corners,

wherein the corners each include a linear portion having a same width dimension as the sides in the plan view of the principal surface of the base member, a first curve connecting a first side of the sides to the linear portion, and a second curve connecting a second side of the sides to the linear portion;

the first curve and the second curve each include a first rounded portion having a first radius and a second rounded portion concentric with the first rounded portion and having a second radius different from the first radius; and

a difference between the first radius and the second radius is equal to the width dimension of the linear portion in the plan view of the principal surface of the base member.

17. A piezoelectric resonator unit comprising:

a piezoelectric resonator;

a lid member and a base member defining an internal space that accommodates the piezoelectric resonator; and

a joining member joining the lid member and the base member,

wherein in a plan view of a principal surface of the base member, the joining member has a frame shape with a uniform width dimension surrounding the piezoelectric resonator,

wherein the joining member includes:

a sealing frame in the frame shape on the principal surface of the base member and disposed along an entire circumference of the lid member; and

a joining material in the frame shape on the sealing frame,

wherein the frame shape is a rectangular shape including sides and corners, and in the plan view of the principal surface of the base member, a width dimension of the sides is equal to a width dimension of the corners, and

wherein the base member includes respective anti-alloying films adjacent to each of the corners.

18. The piezoelectric resonator unit according to claim 17 , wherein the corners each include a first rounded portion having a first radius and a second rounded portion concentric with the first rounded portion and having a second radius different from the first radius; and

in the plan view of the principal surface of the base member, a difference between the first radius and the second radius is equal to the width dimension of the sides.

19. A piezoelectric resonator unit manufacturing method, the method comprising:

preparing a base member;

holding a piezoelectric resonator on a principal surface of the base member; and

joining a lid member to the base member with a joining member,

wherein in a plan view of the principal surface of the base member, the joining member has a frame shape surrounding the piezoelectric resonator, and the frame shape has a uniform width

wherein the lid member and the joining member are each made of a metal material; and the joining of the lid member to the base member includes heating and melting the joining member,

wherein the frame shape is a rectangular shape including corners;

the corners each include a rounded portion; and

the joining of the lid member to the base member includes positioning respective anti-alloying films adjacent to each of the corners and forming the rounded portion of each corner using a corresponding one of the anti-alloying films.

20. The piezoelectric resonator unit manufacturing method according to claim 19 , further comprising:

adding a sealing frame on the principal surface of the base member;

adding a joining material on the lid member sealing frame; and

joining the sealing frame and the joining material to form the joining member.