Optical module
An optical module includes: a stem made of metal; a ground pin including a pin portion and a joint portion having a diameter larger than a diameter of the pin portion and joined to an outer flat surface of the stem; a flexible printed circuit including a wiring pattern on a front surface and a ground pattern having an exposed surface at a position facing the outer flat surface of the stem on a back surface, in which a tip portion of the pin portion of the ground pin penetrating a second through hole is electrically connected to the second through hole on the front surface; and a plate made of metal, having a back surface joined to the outer flat surface of the stem and a front surface joined to the exposed surface of the ground pattern.
1. An optical module, comprising:
a stem made of metal having an inner flat surface and an outer flat surface and having a through hole formed to penetrate between the inner flat surface and the outer flat surface;
a signal lead pin that penetrates the through hole of the stem, is electrically insulated and fixed to the stem, and includes an inner lead portion projecting from the inner flat surface of the stem and an outer lead portion projecting from the outer flat surface of the stem;
a ground pin including a pin portion, and at an end of the pin portion, a joint portion having a diameter larger than a diameter of the pin portion and joined to the outer flat surface of the stem;
a flexible printed circuit including a wiring pattern on a front surface and a ground pattern having an exposed surface at a position facing the outer flat surface of the stem on a back surface, wherein a first through hole is formed at a position facing the signal lead pin in the wiring pattern, the outer lead portion of the signal lead pin penetrates the first through hole, a tip portion of the outer lead portion of the signal lead pin is electrically connected to the wiring pattern, a second through hole is formed at a position facing the ground pin in the exposed surface of the ground pattern, the pin portion of the ground pin penetrates the second through hole, and a tip portion of the pin portion of the ground pin is electrically connected to the second through hole on the front surface; and
a plate made of metal having a back surface joined to the outer flat surface of the stem and a front surface joined to the exposed surface of the ground pattern.
2. The optical module according to claim 1 , wherein the exposed surface of the ground pattern and the front surface of the plate are bonded by a conductive adhesive, and the outer flat surface of the stem and the back surface of the plate are bonded by a conductive tape.
3. The optical module according to claim 1 , wherein a planar shape of the plate is a shape in which an outer shape conforms to an outer shape of the outer flat surface of the stem, and from which a surface through which the signal lead pin and the ground pin pass separately is removed.
4. The optical module according to claim 1 , wherein
a semiconductor light-emitting element, a light-receiving element, and a temperature adjusting device are mounted in a CAN type package including the stem and a lens cap fixed in contact with a peripheral end portion of the inner flat surface of the stem, and
the signal lead pin is configured as a signal lead pin for the semiconductor light-emitting element.
5. The optical module according to claim 4 , wherein a dielectric substrate having a high frequency line connecting between the semiconductor light-emitting element and the signal lead pin for the semiconductor light-emitting element is mounted in the CAN type package.