Panasonic Intellectual Property Management Co., Ltd.

Panasonic Holdings Corporation

Panasonic Corporation

Matsushita Electronics Corporation

Masayuki Kubo

Koji Yoshino

Hiroshi Sakurai

Tomotaka Nobue

Yuji Hayakawa

Masafumi Sadahira

Yoshiharu Omori

Osamu Hashimoto

Ryosuke Suga

Kenji Yasui

Yoshiharu Oomori

Daisuke Hosokawa

Yoshiki Hayashida

Takahide Yamaguchi

Hideki Nakamura

Junji Hirata

Keijirou Kunimoto

Katsuyuki Yamashita

Takayuki Akashi

Masaharu Tsujimoto

A microwave treatment apparatus includes a treatment chamber, a microwave supply, and a resonator unit. The treatment chamber is surrounded by a plurality of walls, and accommodates a heating target. The microwave supply supplies a microwave to the treatment chamber. The resonator unit is provided on one wall of the plurality of walls, and the resonator unit has a resonance frequency in a frequency band of the microwave. In this embodiment, the impedance of the surface of the resonator unit can be changed by controlling the frequency of the microwave supplied to the treatment chamber. This makes it possible to control the standing wave distribution within the treatment chamber, that is, the microwave energy distribution within the treatment chamber. As a result, in the cases where a plurality of heating targets need to be heated simultaneously, desired dielectric heating is conducted for each of the heating targets.

Microwave processing device

A microwave heating device includes a heating chamber that accommodates an object to be heated, a microwave generator configured to generate microwaves, a wave guide tube configured to guide the microwaves to the heating chamber, and an electromagnetic field distribution adjustment device that is provided in a two-dimensional region located in at least a part of a wall face within the heating chamber. The electromagnetic field distribution adjustment device has a plurality of metal pieces arranged to fill a predetermined two-dimensional region, and a switch provided between two metal pieces adjacent to each other among the plurality of metal pieces. The switch is connected to the two metal pieces adjacent to each other through two conductors each of which is provided on a corresponding one of the two metal pieces adjacent to each other, and smaller than the two metal pieces adjacent to each other. According to the present aspect, uneven heating, which is caused by heating an object to be heated with a microwave heating device, can be reduced.

Electromagnetic field distribution adjustment device and microwave heating device

A microwave heating device includes a heating chamber that accommodates an object to be heated, a microwave generator configured to generate microwaves, a wave guide tube configured to guide the microwaves to the heating chamber, and an electromagnetic field distribution adjustment device provided in a predetermined two-dimensional region within the heating chamber. The electromagnetic field distribution adjustment device has a plurality of metal pieces and a plurality of switches. The plurality of metal pieces are arranged to fill the predetermined two-dimensional region. The plurality of switches connect the plurality of metal pieces with one another. A serially connected row of metal pieces is configured by connecting one metal piece among the plurality of metal pieces to at most two metal pieces adjacent to the one metal piece through at least two of the plurality of switches. The present exemplary embodiment can achieve a low-cost electromagnetic field distribution adjustment device that heats an object to be heated more uniformly, while preventing a drop in heating efficiency.

A rotating antenna () includes: a ceiling surface () and a side-wall surface () that constitute a waveguide structure (); and a horn () that radiates a microwave into a heating chamber. The rotating antenna () further includes a flange () that is formed on a periphery of the side-wall surface () so as to face a bottom surface (), which is an inner wall surface of the heating chamber, and so as to surround the side-wall surface (). The flange () has choke sections () that reduce a leakage of the microwave. This configuration can generate a relatively low impedance region so as to surround the side-wall surface (), thereby enhancing a leakage reducing performance of the rotating antenna () and increasing directivity of the microwave radiated from the rotating antenna (). Consequently, if a part of substances to be heated arranged on a plate is a food that a user does not want to warm, the rotating antenna () selectively heats an area in which a food that the user wants to warm is present but hardly heats the food that the user does not want to warm.

Microwave heating device

The present invention includes a directional coupler that detects at least part of a reflected wave inside a waveguide. When an object to be heated is absent, a reflected wave is strong, because there is nothing to absorb a microwave. When the object is present, the reflected wave is weak, because the microwave is absorbed by the object. As a quantity of the object becomes greater, a larger amount of microwave is absorbed by the object, and thus the reflected wave is weakened. It is thus possible to determine the quantity of the object from a reflected wave detection amount detected by the directional coupler without using a detector that detects a load.

Microwave heating apparatus

The present invention has a configuration of controlling a motor so as to stop a radiation antenna when the radiation antenna faces in a direction in which a reflected wave detection amount is minimized and to stop the radiation antenna when the radiation antenna faces in a different direction different from the direction in which the reflected wave detection amount is minimized. According to this configuration, first, the radiation antenna stops when facing in the direction in which the reflected wave detection amount is minimized. This extends a heating time under the most efficient condition, improving a heating efficiency in comparison with when the radiation antenna constantly rotates. Second, the radiation antenna stops when facing in the different directions. This causes uneven heating when the radiation antenna faces in the direction in which the reflected wave detection amount is minimized as well as when the radiation antenna faces in the different directions. As a result, the uneven heating is cancelled out by the uneven heating each other caused at different locations. In this way, it is possible to achieve the even heating.

There are provided heating chamber, and reflection angle control device provided on upper wall configuring at least part of walls of heating chamber and configured to control a reflection angle of a microwave to control standing wave distribution in heating chamber. Reflection angle control device controls the reflection angle of the microwave when the microwave radiated from microwave radiation device is not directly absorbed into heating target but is reflected by the wall. Standing wave distribution in heating chamber can thus be controlled to be different from ordinary distribution for improvement in local heating performance.

A microwave oven includes a waveguide having an E-bend structure with multiple openings disposed on a lateral face of a heating chamber that allow the waveguide to communicate with the heating chamber. The waveguide has a first section for propagating a microwave from a magnetron toward the heating chamber, and a second section having a wide plane that abuts an outer wall of the heating chamber. The openings include at least one circularly-polarized-wave opening for generating a circularly polarized wave. A cross section of the first section orthogonally intersects a tube axis of the first section projects virtually along the tube axis of first section and onto a lateral face of the heating chamber, and the circularly-polarized-wave opening is configured such that its center is located outside the resultant projected region.

Microwave treatment apparatus

A microwave heating apparatus includes: a heating chamber which houses a heating object; a microwave generating unit which generates a microwave; a transmitting unit which transmits the microwave generated by the microwave generating unit; a waveguide-structure antenna which radiates to the heating chamber the microwave transmitted from the transmitting unit; and a rotation driving unit which drives the waveguide-structure antenna to rotate, wherein the waveguide-structure antenna has a microwave sucking-out opening in a wall surface forming a waveguide structure of the waveguide-structure antenna.

A directional coupler according to the invention includes an opening in a wall surface of a waveguide, and a coupling line on an outer side of the waveguide. The opening is configured to not cross a tube axis of the waveguide in plan view, and to emit a circularly polarized wave. The coupling line includes first and second transmission lines and output parts disposed at both ends, the first and second transmission lines extending across the opening to cross the tube axis in plan view and being opposed to each other across the center of the opening. The first and second transmission lines are interconnected at a position displaced from an area vertically above the opening.

Growing community of inventors

Shiga, Japan

Masayuki Kubo