Murata Manufacturing Co., Ltd.

Murata Mfg. Co., Ltd.

Yuichi Takaoka

Takashi Shikama

Hideaki Niimi

Kenjiro Mihara

Yutaka Ikeda

Takayo Katsuki

Kiyofumi Torii

Yoshihiro Yamada

Hidehiro Inoue

Tomozo Yamanouchi

Shinichi Osada

Kenjirou Mihara

Hiroshi Ohta

Tomoaki Tadokoro

Shinji Omura

Tomoyuki Yamamoto

Kenji Takakura

Kenji Nagareda

Shigehiro Ichida

Osamu Watanabe

Akira Toba

Mitsuaki Fujimoto

Masahito Mihara

Kouichi Tatsuoka

Masaru Nakagawa

Masahiro Yokota

Organic thermistor devices are produced by a first step of molding an organic thermistor material by covering a plurality of electrically conductive members to form a conductor-containing member, which is elongated in a longitudinal direction, has a pair of mutually oppositely facing side surfaces, having the conductive plates buried parallel to one another inside the organic thermistor material, each mutually adjacent pair of these conductive members being externally exposed on different ones of the side surfaces, a second step of forming a pair of electrodes elongated in the longitudinal direction on the side surfaces of the conductor-containing member, and a third step of thereafter cutting this conductor-containing member transversely at specified positions so as to divide into individual units.

Method of producing organic thermistor devices

A semiconductor ceramic for thermistors contains zinc oxide and titanium oxide as main components and a predetermined content of manganese. Also, a chip-type thermistor including the semiconductor ceramic is provided. By adding manganese, the resistance-temperature characteristic is controllable in the range of positive temperature coefficient to negative temperature coefficient. Also, by adding nickel, the resistivity is controllable. As a result, a thermistor material which provides a series of semiconductor ceramics having various resistivities and various B constants in a low range, for example 0 to 1,000 K, is available.

Semiconductor ceramic for thermistors and chip-type thermistor including the same

A thermistor element has a pair of electrodes formed in ohmic contact with and mutually opposite to each other on one of the surfaces of a thermistor body. These electrodes each have a thin-film contact layer and an external electrode layer which is formed either directly or indirectly over the contact layer and only on the surface on which these electrodes are formed opposite each other and is of a metallic material such as Au, Ag, Pd, Pt, Sn and their alloys.

Thermistor elements

An NTC thermistor has an electrically insulating substrate, a temperature-sensitive film on a surface of the substrate containing oxide of rare earth elements such as LaCoO as its principal component by at least 50 weight %, and a pair of electrodes which are separated from each other and are each electrically connected to this film. An NTC thermistor chip is obtained by further forming a pair of outer electrodes which are each on a corresponding end portion and electrically connected to a corresponding one of the surface electrodes.

NTC thermistors and NTC thermistor chips

An organic thermistor device has a pair of outer electrodes formed facing each other on end parts of a thermistor body made of an organic thermistor material. Metallic wires extend inside and through the thermistor body transversely to the direction in which the outer electrodes face each other such that the resistance value at normal temperatures of the device can be significantly reduced. Both exposed surfaces of the thermistor body not covered by the outer electrodes and exposed end surfaces of the metallic wires not covered by the thermistor body may be all covered by an electrically insulating layer. To produce such organic thermistor devices, an elongated wire-containing member is prepared by molding an organic thermistor material by covering metallic wires extending longitudinally parallel to one another. It is then entirely covered with an electrically insulating material but portions of it are removed from a pair of longitudinally continuous external peripheral surface areas. Outer electrodes are thereafter formed on this pair of surface areas and the wire-containing member is then cut transversely to the direction of its elongation at specified positions to divide into individual elements. The newly exposed surfaces of these individual elements by cutting may be covered by an electrically insulating material.

Organic thermistor device and method of producing same

A high-frequency detecting element that can detect a temperature increase in an instant due to high-frequency wave absorption using semiconducting ceramic with positive resistance-temperature characteristics. The ceramic is composed mainly of barium titanate. A high-frequency heater incorporating the high-frequency detecting element is also disclosed. In the high-frequency detecting element, electrodes are provided on one main surface of semiconducting ceramic,with positive resistance-temperature characteristics and leads,and,are soldered to the electrodes,and

High-frequency detecting elements and high-frequency heater using the same

A chip-type thermistor has a pair of electrically conductive planar comb-shaped surface electrodes facing each other on one of principal surfaces of a thermistor block, and an insulating layer covers these surface electrodes. A pair of outer electrodes are formed on end surfaces of the thermistor block, each electrically connected to an associated one of the surface electrodes.

Thermistor with comb-shaped electrodes

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.

PTC thermistor elements and heating devices incorporating same

A degaussing circuit is formed as a series connection of a PTC element and a degaussing coil operated such that the operating frequency of the current therethrough is higher than the frequency of the power source line for the device such as a color television set in which this degaussing circuit is incorporated. This frequency conversion may be effected by a circuit which also functions to convert the alternating current from the power source line into a direct current. The degaussing circuit may further include a relay circuit for switching on and off the current through the PTC element and the degaussing coil.

Degaussing circuit with a PTC thermistor

A thermistor for surface mounting includes a first conductive terminal member, a case having a top opening, a planar thermistor element having electrodes on mutually opposite main surfaces thereof, and a second conductive terminal member having at one end thereof a planar cover part which is attached to the top part of the case. One end of the first terminal member is positioned inside the case and above its bottom member. The other ends of the first and second terminal members are positioned on the bottom surface of the case.

Electronic apparatus and surface mounting devices therefor

A demagnetizing circuit and a current limiting device for being built into a power supply circuit of a color television receiver or color monitor display or the like with which it is possible to effect a reliable demagnetizing operation using existing components and without using either a positive characteristic thermistor which reaches a high temperature or a relay circuit. The demagnetizing circuit is connected in parallel with a power supply circuit having a smoothing capacitor and a negative temperature characteristic thermistor or fixed resistance for suppressing surge currents to the smoothing capacitor. It has a thermally actuated switch connected in series with one end of a demagnetizing coil by way of a positive temperature characteristic thermistor which is actuated by heat produced by the temperature negative characteristic thermistor or fixed resistance to cut off a demagnetizing current. The current limiting device within the demagnetizing circuit includes the negative temperature characteristic thermistor or fixed resistance, the positive temperature characteristic thermistor and the thermally actuated switch interposed between the negative temperature characteristic thermistor or fixed resistance and the positive temperature characteristic thermistor. The thermally actuated switch has a thermally actuated member which is caused to bend by heat produced by the negative characteristic temperature thermistor or fixed resistor, and a moving contact point and a fixed contact point which are opened by this bending of the thermally actuated member.

Demagnetizing circuit and current limiting device

A demagnetizing circuit has a positive characteristic thermistor and a demagnetizing coil connected in series with an alternating current power supply and is so constructed that it is possible to suppress the production of a low-frequency electromagnetic field. After the completion of a demagnetizing operation, the demagnetizing coil and the alternating current power supply can be completely isolated from each other, i.e. both ends of the demagnetizing coil can be electrically cut off from the alternating current power supply, so that it is impossible for residual demagnetizing current from the alternating current power supply to produce a low-frequency electromagnetic field in the demagnetizing coil. Also, preferably, at least one end of the demagnetizing coil is kept at a reference potential by way of a capacitor to dissipate any currents which may be induced in the demagnetizing coil by any influence other than the alternating current power supply.

Demagnetizing circuit

A high-frequency detecting element that can detect a temperature increase in an instant due to high-frequency wave absorption using semiconducting ceramic with positive resistance-temperature characteristics. The ceramic is composed mainly of barium titanate. A high-frequency heater incorporating the high-frequency detecting element is also disclosed. In the high-frequency detecting element, electrodes are provided on one main surface of semiconducting ceramic 1 with positive resistance-temperature characteristics and leads 3a and 3b are soldered to the electrodes 2a and 2b.

High-frequency detecting elements and high-frequency heater using the

A rush current suppression circuit suppresses a peak value of a rush current flowing into a heater. The rush current suppression circuit includes a parallel circuit formed by a positive-characteristic thermistor and a negative-characteristic thermistor. The negative-characteristic thermistor has a resistance at a normal temperature higher than that of the positive-characteristics thermistor. The parallel circuit is connected in series to the heater.

Rush current suppression circuit

A method of supplying positive temperature coefficient thermistor elements in which a plurality of positive temperature coefficient thermistor elements 1 are divided into groups G.sub.1 to G.sub.8 for each range of predetermined resistance values, two arbitrary positive temperature coefficient thermistor elements are taken out of one of the groups G.sub.1 to G.sub.8 and supplied as one set of positive temperature coefficient thermistor elements.

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Shiga, Japan

Yuichi Takaoka