Polytronics Technology Corporation

Kuo Chang Lo

Yi An Sha

David Shau Chew Wang

Fu Hua Chu

Yao Te Chang

Chun Teng Tseng

Tsungmin Su

Jyh Ming Yu

Tong Cheng Tsai

Shau Chew Wang

Wei Tsang Dai

Ya Fang Liang

Chien Cheng Ho

Tai Kuang Hei

Chin Piao Yang

A PTC composition comprises crystalline polymer and conductive filler. The conductive filler comprises tungsten carbide powder dispersed in the crystalline polymer, and the tungsten carbide powder comprises impurity of less than 7% by weight. The impurity comprises the materials other than tungsten monocarbide.

PTC composition and over-current protection device containing the same

A PTC device comprises two electrode layers and a PTC material layer laminated therebetween. The PTC material layer has a volumetric resistivity less than 0.2 &#x3a9;-cm, and comprises a crystalline polymer, conductive ceramic fillers and crystalline low molecular weight organic compound. The crystalline polymer comprises thermoplastic polymer, thermosetting polymer or combination thereof. The conductive ceramic fillers dispersed in the crystalline polymer have volumetric resistivity less than 500 &#x3bc;&#x3a9;-cm, and comprise 40-70% by volume of the PTC material layer. The crystalline low molecular weight organic compound has a molecular weight less than 5000, and comprises 6-30% by volume of the PTC material layer. The hold current at 60&#xb0; C. divided by a covered area of the PTC device is greater than 0.2 A/mm, the hold current at 60&#xb0; C. is 40-95% of the hold current at 25&#xb0; C., and the trip temperature of the PTC device is less than 95&#xb0; C.

Positive temperature coefficient device

A PTC composition comprises crystalline polymer and conductive ceramic filler dispersed therein. The crystalline polymer has a melting point less than 90&#xb0; C. and comprises 5%-30% by weight of the PTC composition. The crystalline polymer comprises ethylene, vinyl copolymer or the mixture thereof. The vinyl copolymer comprises at least one of the functional group selected from the group consisting of ester, ether, organic acid, anhydride, imide or amide. The conductive ceramic filler comprises a resistivity less than 500 &#x3bc;&#x3a9;-cm and comprises 70%-95% by weight of the PTC composition. The PTC composition has a resistivity about 0.01-5 &#x3a9;-cm and its resistance at 85&#xb0; C. is about 10to 10times that at 25&#xb0; C.

PTC composition and resistive device and LED illumination apparatus using the same

An over-current protection device includes two metal foils and a PTC material layer. The PTC material layer is laminated between the two metal foils and has a resistivity less than 0.4 &#x3a9;-cm. The PTC material layer includes crystalline polymer and electrically conductive ceramic filler dispersed in the crystalline polymer. The conductive ceramic filler is of HCP structure and includes 70-95% by weight of the PTC material layer. The trip jump value of the over-current protection device after 300 times trip is less than or equal to 25. The resistance repeatability of the device can be effectively improved by adding the conductive ceramic filler.

Over-current protection device

A thermistor includes a first electrically conductive member, a second electrically conductive member and a polymer material layer laminated therebetween. The polymer material layer exhibits positive temperature coefficient (PTC) behavior, and includes at least one crystalline polymer and at least one electrically conductive filler distributed in the crystalline polymer. The conductive filler has a resistivity less than 500 &#x3bc;&#x3a9;-cm and includes 72-96% by weight of the polymer material layer. The thermistor has a device effective area, and the value of the hold current at 60&#xb0; C. divided by the device effective area is around 0.16-0.8 A/mm. The ratio of the hold current of the thermistor at 60&#xb0; C. to the hold current at 25&#xb0; C. of the thermistor is 40-95%.

Thermistor

An over-current protection device includes two metal foils and a PTC material layer laminated therebetween. The PTC material layer has a volume resistivity between 0.07 &#x3a9;-cm and 0.32 &#x3a9;-cm. The PTC material layer includes a crystalline polymer, a conductive ceramic carbide filler of a particle size between 0.1 &#x3bc;m and 50 &#x3bc;m and a volume resistivity less than 0.1 &#x3a9;-cm, and a carbon black filler. The weight ratio of the carbon black filler to the conductive ceramic carbide filler is between 1:90 and 1:4. The conductive ceramic carbide filler and the carbon black filler are dispersed in the crystalline polymer. The resistance ratio R/Ri is between 3 and 20.

An over-current protection device comprises two metal foils, a positive temperature coefficient (PTC) material layer and a packaging material layer. The PTC material layer is sandwiched between the two metal foils and has a volume resistivity below 0.1 &#x3a9;-cm. The PTC material layer includes (i) plural crystalline polymers having at least one crystalline polymer with a melting point less than 115&#xb0; C.; (ii) an electrically conductive nickel filler having a volume resistivity less than 500 &#x3bc;&#x3a9;-cm; and (iii) a non-conductive metal nitride filler. The electrically conductive nickel filler and non-conductive metal nitride filler are dispersed in the crystalline polymer. The packaging material layer which encapsulates the chip is essentially comprised of the PTC layer and the two metal foils. The packaging material layer is formed by reacting epoxy resin with a hardener having amide functional group.

An over-current protection device comprises two metal foils and a positive temperature coefficient (PTC) material layer. The PTC material layer is sandwiched between the two metal foils and has a volume resistivity below 0.1 &#x3a9;-cm. The PTC material layer includes (i) plural crystalline polymers having at least one crystalline polymer of a melting point less than 115&#xb0; C.; (ii) an electrically conductive nickel filler having a volume resistivity less than 500 &#x3bc;&#x3a9;-cm; and (iii) a non-conductive metal nitride filler. The electrically conductive nickel filler and non-conductive metal nitride filler are dispersed in the crystalline polymer.

An over-current protection device comprises two metal foils and a positive temperature coefficient (PTC) material layer. The PTC material layer is sandwiched between the two metal foils and comprises plural crystalline polymers with at least one polymer melting point below 115&#xb0; C., and a non-oxide electrically conductive ceramic powder. The non-oxide electrically conductive ceramic powder exhibits a certain particle size distribution. The PTC material layer has a resistivity below 0.1 &#x3a9;-cm. The initial resistance of the device is below 20 m&#x3a9;, and the area of the PTC material layer is below 30 mm. The over-current protection device exhibits a surface temperature below 100&#xb0; C. under the trip state of over-current protection.

An over-current protection device comprises two metal foils and a PTC material layer laminated between the two metal foils. The PTC material layer essentially comprises a polymer matrix and a conductive filler. The polymer matrix at least comprises a first crystalline polymer, e.g., LDPE, and a second crystalline polymer, e.g., PVDF, in which the melting temperature of the second crystalline polymer subtracting the melting temperature of the first crystalline polymer is equal to or more than 50&#xb0; C. The conductive filler is selected from metallic grain of a volumetric resistivity less than 500 &#x3bc;&#x3a9;-cm, and is distributed in the polymer matrix. The initial volumetric resistivity of the PTC material layer is less than 0.1&#x3a9;-cm, and the trip temperature of the PTC material layer at which the resistance thereof increases to 1000 times the initial resistance subtracting the melting temperature of the first crystalline polymer is less than 15&#xb0; C.

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Kuo Chang Lo