Crystal unit
A crystal unit is provided with a rectangular substrate, a frame which is provided on an upper surface of the substrate, a mounting frame which has joining pads which are provided along the outer circumferential edge of the upper surface and which is provided on the lower surface of the substrate by joining joining terminals provided along the outer circumferential edge of the lower surface of the substrate and its joining pads, a crystal element which is mounted on electrode pads which are provided on the upper surface of the substrate in a region surrounded by the frame, a thermosensitive element which is mounted on connection pads which are provided on the lower surface of the substrate in a region surrounded by the mounting frame, and a lid which is joined to the upper surface of the frame.
1. A crystal unit comprising:
a rectangular substrate,
a frame which is provided on an upper surface of the substrate,
a mounting frame which is provided on a lower surface of the substrate by joining of joining pads which are provided along the outer circumferential edge of its upper surface with joining terminals which provided along the outer circumferential edge of the lower surface of the substrate,
a crystal element which is mounted on electrode pads which are provided on the upper surface of the substrate in a region surrounded by the frame,
a thermosensitive element which is mounted on connection pads which are provided on the lower surface of the substrate in a region surrounded by the mounting frame,
a lid which is joined to the upper surface of the frame, and
first external terminals which are provided on the lower surface of the mounting frame and are electrically connected to the electrode pads through the joining terminals and the joining pads,
wherein the electrode pads are not electrically connected to the connection pads,
wherein the crystal unit is not provided with an IC,
wherein the mounting frame is made of an insulator, and
wherein a clearance portion is provided between the substrate and the mounting frame, the clearance portion being configured to permit air to flow from inside of the mounting frame to outside of the mounting frame.
2. The crystal unit according to claim 1 , wherein, in a state where the crystal element and the thermosensitive element are mounted on the substrate, the thermosensitive element is positioned within the plane for the excitation-use electrodes which are provided on the crystal element when viewed on a plane.
3. The crystal unit according to claim 1 , further comprising:
a connection pattern for electrically connecting one of the connection pads and one of the joining terminals, wherein
the electrode pads are provided in a pair so as to be adjacent to each other along one side of the inner circumferential edge of the frame, and
the connection pattern is positioned between the pair of electrode pads when viewed on a plane.
4. The crystal unit according to claim 1 , further comprising:
an interconnect pattern for electrically connecting one of the electrode pads and one of the joining terminals, wherein
the interconnect pattern is provided on the same plane as that for the connection pad and is provided at a position which overlaps the mounting frame.
5. The crystal unit according to claim 1 , further comprising:
a mounting pad which is electrically connected to one of the connection pads and is provided on the lower surface of the substrate, wherein
the thermosensitive element is mounted on said one of the connection pads and the mounting pad by a conductive bonding material, and
the joining terminals and the joining pads are electrically bonded.
6. The crystal unit according to claim 5 , wherein:
said one of the connection pads and the mounting pad are rectangular in shape, and
the length of one side of said one of the connection pads which faces the center direction of the substrate is shorter than the length of one side of the mounting pad which faces the center direction of the substrate.
7. The crystal unit according to claim 5 , wherein:
the electrode pads are provided in a pair so as to be adjacent to each other along one side of the inner circumferential edge of the frame, and
the mounting pad is positioned between the pair of electrode pads when viewed on a plane.
8. The crystal unit according to claim 1 , further comprising:
a first conductive bonding material which connects one of the joining terminals and one of the joining pads, and
a second conductive bonding material which bonds one of the connection pads and the thermosensitive element, wherein
the first conductive bonding material and the second conductive bonding material are bonded.
9. The crystal unit according to claim 1 , further comprising:
second external terminals which are provided on the lower surface of the mounting frame and are electrically connected to the connection pads through some of the joining terminals and the joining pads which are not electrically connected to the electrode pads, wherein connection conductors connecting the connection pads and the joining terminals are not provided inside of the substrate, but provided only on lower surface of the substrate.