To provide a magnetron in which magnetic flux density in a working space is uniform while using only one magnet, and a microwave oven installed with this magnetron, and further a high frequency heating device.
The magnetron comprises an annular positive electrode part forming numerous resonance circuits, a negative electrode part arranged in the axial center of the positive electrode part with a prescribed space from the positive electrode part and emits thermoelectron, an annular permanent magnet that is provided above the positive electrode part, an upper magnetic pole member having a magnetic flux dispersion structure for guiding the magnetic flux generated by the permanent magnet to the upper part of the prescribed space, a lower magnetic pole member for guiding the magnetic flux to the lower part of the prescribed space, and at least one yoke that connects the permanent magnet with the lower magnetic pole member magnetically.
RAYSKY BORIS V
HA HYUN-JUN
Takashi Watanabe