PTC thermistor elements and heating devices incorporating same
AssigneeMurata Manufacturing Co., Ltd.
InventorsYutaka Ikeda, Takashi Shikama, Yuichi Takaoka, Kenjiro Mihara
Life of this patent
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Abstract
A PTC thermistor element for a heating device has a main body of a layered structure having a thinner layer and a thicker layer, sandwiched between electrodes formed on the main outer surfaces facing away from each other. The thinner layer has a thickness 0.05-0.43 times that of the thicker layer and is made of a PTC thermistor material with a Curie temperature which is lower than that of the thicker layer by 20.degree. C. or more. The center of heat generation is thus shifted towards the electrode formed on the thinner layer, and a heating plate contacting it can be effectively heated.
Claims25
A PTC thermistor element comprising:
- a main body having a first main surface and a second main surface which face mutually oppositely away from each other;
- a first electrode on said first main surface;
- and
- a second electrode on said second main surface;
- said main body comprising PTC thermistor materials and having a layered structure consisting of a first layer including said first main surface and a second layer including said second main surface, said first layer having a thickness 0.05-0.43 times that of said second layer, said first layer having a Curie temperature which is lower than that of said second layer by 20.degree. C. or more.
A PTC thermistor element comprising:
- a main body having a first main surface and a second main surface which face mutually oppositely away from each other;
- a first electrode on said first main surface;
- and
- a second electrode on said second main surface;
- said main body comprising PTC thermistor materials and having a layered structure consisting of two outer layers and one or more inner layers extending parallel to said first main surface and said second surface between said two outer layers, said two outer layers consisting of a first outer layer including said first main surface and a second outer layer including said second main surface, at least one of said two outer layers having a thickness 0.05-0.43 times that of said one or more inner layers, at least one of said two outer layers having a Curie temperature which is lower than that of said one or more inner layers by 20.degree. C. or more.
A heating device comprising a PTC thermistor element and a metallic heating plate, said PTC thermistor element comprising:
- a main body having a first main surface and a second main surface which face mutually oppositely away from each other;
- a first electrode on said first main surface, said metallic heating plate contacting said first electrode;
- and
- a second electrode on said second main surface;
- said main body comprising PTC thermistor materials and having a layered structure consisting of a first layer including said first main surface and a second layer including said second main surface, said first layer having a thickness 0.05-0.43 times that of said second layer, said first layer having a Curie temperature which is lower than that of said second layer by 20.degree. C. or more.
A heating device comprising a PTC thermistor element and a metallic heating plate, said PTC thermistor element comprising:
- a main body having a first main surface and a second main surface which face mutually oppositely away from each other;
- a first electrode on said first main surface, said metallic heating plate contacting said first electrode;
- and
- a second electrode on said second main surface;
- said main body comprising PTC thermistor materials and having a layered structure consisting of two outer layers and one or more inner layers extending parallel to said first main surface and said second surface between said two outer layers, said two outer layers consisting of a first outer layer including said first main surface and a second outer layer including said second main surface, at least one of said two outer layers having a thickness 0.05-0.43 times that of said one or more inner layers, at least one of said two outer layers having a Curie temperature which is lower than that of said one or more inner layers by 20.degree. C. or more.
A heating device comprising a PTC thermistor element and metallic heating plates, said PTC thermistor element comprising:
- a main body having a first main surface and a second main surface which face mutually oppositely away from each other;
- a first electrode on said first main surface, at least one of said metallic heating plates contacting said first electrode;
- and
- a second electrode on said second main surface, at least one of said metallic heating plates contacting said second electrode, said main body comprising PTC thermistor materials and having a layered structure consisting of two outer layers and one or more inner layers extending parallel to said first main surface and said second surface between said two outer layers, said two outer layers consisting of a first outer layer including said first main surface and a second outer layer including said second main surface, at least one of said two outer layers having a thickness 0.05-0.43 times that of said one or more inner layers, at least one of said two outer layers having a Curie temperature which is lower than that of said one or more inner layers by 20.degree. C. or more.
Dependencies are inferred from the claim text.