JP5489777B2 - Resistance thermal fuse package and resistance thermal fuse - Google Patents

Description

  The present invention relates to a resistance temperature fuse package in which a temperature fuse element is mounted, and a resistance temperature fuse that heats a heating resistor based on an external signal and blows the temperature fuse element due to the temperature of the heating resistor About.

  In recent years, resistance temperature fuse packages and developments that improve the operating characteristics of resistance temperature fuses have been underway (see, for example, Patent Document 1). In the development of resistance thermal fuses, there is a need for technology that improves the operational characteristics of thermal fuse elements.

JP-A-11-96871

  The present invention has been made in view of the above, and an object of the present invention is to provide a resistance temperature fuse package and a resistance temperature fuse capable of improving operating characteristics.

A resistance temperature fuse according to an embodiment of the present invention is formed by laminating a plurality of substrates, and a base having a recess in a substrate positioned at the uppermost layer, and provided on the base and across the recess A thermal fuse element provided on the base body and formed in a region that overlaps the thermal fuse element as seen through the plane, and is provided in the base body and below the heat generation resistor body. A hollow portion is provided in a region that overlaps with the heating resistor as seen through the plane .

The resistance thermal fuse package according to the embodiment of the present invention is formed by laminating a plurality of substrates, and has a recess in the substrate located in the uppermost layer, and the temperature over both regions sandwiching the recess in plan view. A base having a mounting surface on which the fuse element is mounted, and a heating resistor provided in a region of the base that overlaps the mounting surface in a plan view, the heating resistance being provided in the base A cavity is provided below the body in a region that overlaps with the heating resistor as seen through a plane .

  ADVANTAGE OF THE INVENTION According to this invention, the resistance temperature fuse package which can improve an operation characteristic, and a resistance temperature fuse can be provided.

It is a perspective view which shows the general view of the resistance temperature fuse which concerns on this embodiment. 1 is a perspective view showing an overview of a resistance temperature fuse package according to an embodiment. FIG. It is a disassembled perspective view of the base | substrate of the resistance temperature fuse which concerns on this embodiment. FIG. 3 is a cross-sectional view of a resistance thermal fuse taken along X-X ′ in FIG. 2. It is a perspective view which shows the external appearance of the resistance temperature fuse which concerns on one modification. It is a disassembled perspective view of the base | substrate of the resistance temperature fuse which concerns on one modification.

  Embodiments of a resistance temperature fuse and a resistance temperature fuse package according to the present invention will be described below with reference to the accompanying drawings. In addition, this invention shall not be limited to the following embodiment.

<Schematic configuration of resistance thermal fuse>
FIG. 1 is a schematic perspective view of a resistance thermal fuse according to this embodiment, in which a flux covering a thermal fuse element is formed. FIG. 2 is a schematic perspective view of the resistance thermal fuse package according to the present embodiment, showing a state in which the thermal fuse element and the flux are removed. Note that the flux in FIG. 1 is transmitted.

  FIG. 3 is an exploded perspective view of the thermal fuse package shown in FIG. FIG. 4 is a cross-sectional view taken along X-X ′ in FIG. 2.

  The resistance temperature fuse 1 of the present embodiment is used as a circuit protection element, and is incorporated in a specific circuit together with an abnormality detector. When a circuit abnormality occurs, the abnormality detector detects the circuit abnormality and energizes the heating resistor. As a result, in the resistance temperature fuse 1, the heat generating resistor becomes high temperature, and the operation of the circuit is urgently stopped by fusing the temperature fuse element according to the temperature.

  The resistance thermal fuse 1 according to this embodiment includes a resistance thermal fuse package 2 and a thermal fuse element 3 mounted on the resistance thermal fuse package 2.

  The resistance thermal fuse package 2 according to the present embodiment is formed by stacking a plurality of substrates, and has a recess P in the uppermost substrate, and covers both regions sandwiching the recess P in plan view. A base body 4 having a mounting surface R on which the thermal fuse element 3 is mounted, and a heating resistor 5 provided on the base body 4 and formed in a region overlapping the mounting surface R as seen through the plane.

  The base 4 is formed by laminating a plurality of insulating substrates, and is made of, for example, a ceramic material such as alumina, mullite, or aluminum nitride, or a glass ceramic material. Or it consists of a composite material which mixed several materials among these materials. In addition, the thickness of the board | substrate which comprises the base | substrate 4 is set to 0.05 mm or more and 2 mm or less, for example. The thermal conductivity of the substrate is set to, for example, 14 W / m · K or more and 200 W / m · K or less.

  An electrode layer 6 that is electrically connected to the thermal fuse element 3 when the thermal fuse element 3 is mounted is formed on the upper surface of the substrate 4 a located at the uppermost layer of the base 4.

  The electrode layer 6 is provided between the base 4 and the thermal fuse element 3. A part of the electrode layer 6 is formed from the upper surface of the substrate 4 to the inside of the substrate 4 through the side surface of the substrate 4. In the present embodiment, the first substrate located on the uppermost layer of the base 4 is referred to as a first substrate 4a, and the second substrate located immediately below the uppermost layer of the base 4 is referred to as a second substrate 4b.

  A part of the electrode layer 6 extending into the base 4 is formed up to the upper surface of the second substrate 4b. Then, it is electrically connected to the heating resistor 5 formed on the upper surface of the second substrate 4b.

  The electrode layer 6 is formed so that the electrical connection state of the electrode layer 6 is electrically open when the thermal fuse element 3 is melted. The electrode layer 6 is electrically connected to the thermal fuse element 3 and is formed in an arbitrary pattern. The width of the electrode layer 6 is set to, for example, 0.05 mm or more and 10 mm or less. Here, the width of the electrode layer 6 refers to the width in the direction orthogonal to the direction of the current flowing in the electrode layer 6.

The uppermost layer of the electrode layer 6 to be joined to the thermal fuse element 3 is composed of a single component of the main component constituting the thermal fuse element 3, a laminated film of a plurality of components, or an alloy film of a plurality of components. The electrode layer 6 is made of, for example, a conductive material such as indium, bismuth, or tin, a laminated film thereof, or an alloy film thereof.

  By making the uppermost layer of the electrode layer 6 a single component of the main component of the thermal fuse element 3, a laminated film of a plurality of components, or an alloy film of a plurality of components, the heat of the heating resistor 5 is transmitted to the mounting region R, When melting of the thermal fuse element 3 joined to and contacting the thermal fuse mounting surface including the mounting region R is started, the junction between the electrode layer 6 and the thermal fuse element 3 is wettable with the molten thermal fuse element composition. The boundary line between the bonding location and the surface of the first substrate 4a located around the bonding location is melted due to the good wetting or the difference in wettability with the surface of the first substrate 4a located around the bonding location. By promoting spheroidization or hill-like formation as the outermost extension part of the thermal fuse element composition, the operation performance as the thermal fuse element 3 can be stabilized.

  Further, a material constituting the uppermost layer of the electrode layer 6 is added to the constituent component composition of the thermal fuse element 3 so that the melting temperature of the composition of the thermal fuse element 3 can be lowered. Or by adding to the constituent component composition of the thermal fuse element 3 to make the component effective to lower the melting temperature of the thermal fuse element 3, spheroidization that becomes the outermost extension part of the melting temperature fuse element, Alternatively, by promoting the formation of hills, it is possible to stabilize the operation performance as the thermal fuse element.

  The recess P formed in the substrate 4a is formed at the center position of the first substrate 4a. And a part of electrode layer 6 is extended to the area | region which the recessed part P adjoins. Further, a part of the electrode layer 6 and a part of the thermal fuse element 3 are electrically connected. The recess P penetrates the substrate 4a, and when the substrate 4a and the substrate 4b are overlapped, a part of the upper surface of the substrate 4b is exposed from the recess P. The concave portion P has a side length of, for example, 1 mm or more and 11 mm or less in plan view. Moreover, the depth of the recessed part P is set to 0.02 mm or more and 2 mm or less, for example.

  In the recess P, when the thermal fuse element 3 is melted, it is not oppositely absorbed due to the spheroidization or hill formation of the composition of the thermal fuse element 3 at the junction between the electrode layer 6 and the thermal fuse element 3. A melt of the composition of the thermal fuse element 3 between the joints to be accommodated is accommodated. If the concave portion P does not exist, the molten material of the temperature fuse element 3 melted at the temperature at which the temperature fuse element 3 is melted is attached to the first substrate 4a, and a minute amount is formed between the electrode layers 6. There is a possibility that a conductive path is formed and the electrode layer 6 cannot be opened electrically. On the other hand, when the recess P exists, the melted material flows into the recess P, and the electrode layer 6 can be easily opened electrically.

  The second substrate 4b located at the lowermost layer of the base 4 serves as a base when the resistance temperature fuse 1 is provided in an external circuit. And the board | substrate 4b located in the lowest layer of the base | substrate 4 can become a foundation for joining with an external circuit.

  A conductive layer 7 is formed on the lower surface of the second substrate 4b located in the lowermost layer of the base 4. The conductive layer 7 is formed between the first substrate 4 a and the second substrate 4 b from the lower surface of the substrate 4 through the side surface of the substrate 4. By detecting the abnormality of the circuit by the abnormality detector incorporated in the circuit together with the resistance temperature fuse 1, the heating resistor 5 is energized through the conductive layer 7 to increase the temperature of the heating resistor 5. Furthermore, the thermal fuse element 3 can be blown due to the temperature of the heating resistor 5. The width of the conductive layer 7 is set to 0.05 mm or more and 10 mm or less, for example. Here, the width of the conductive layer 7 refers to the width in the direction orthogonal to the direction of current flowing in the conductive layer 7.

The conductive layer 7 is made of, for example, a metal material such as tungsten, molybdenum, nickel, copper, silver, or gold, an alloy thereof, a composite material in which a plurality of materials are mixed, or a composite layer of these materials.

  The thermal fuse element 3 is mounted on the first substrate 4 a located in the uppermost layer of the base 4 so as to straddle the recess P. The thermal fuse element 3 is blown when the temperature exceeds a specific temperature. The thermal fuse element 3 is made of a conductive material such as indium, bismuth or tin, or a mixed material thereof. Further, the melting point at which the thermal fuse element 3 melts is set to, for example, 80 ° C. or higher and 180 ° C. or lower.

  At least a part of the thermal fuse element 3 is provided in a region overlapping with the heating resistor 5 when seen in a plan view, and is formed in a rectangular shape. The thickness of the thermal fuse element 3 is, for example, not less than 0.1 mm and not more than 0.5 mm, and the length of one side in a plan view is set, for example, not less than 0.1 mm and not more than 5.0 mm. .

  The heating resistor 5 is a region that overlaps the thermal fuse element 3 when seen through the plane, and is formed in the base body 4 with a gap from the thermal fuse element 3. As shown in FIG. 3, the heating resistor 5 is formed on the upper surface of the second substrate 4 b of the base 4. The heating resistor 5 transmits the temperature of heat generated to the thermal fuse element 3 and melts the thermal fuse element 3. The heating resistor 5 is provided via the thermal fuse element 3 and the first substrate 4a.

  As shown in FIG. 3, the heating resistor 5 has one end connected to the electrode layer 6 and the other end connected to the conductive layer 7. The heating resistor 5 has a resistance value for securing a required amount of heat generation. As an example of the resistance value securing method, the pattern shape is bent many times on the upper surface of the second substrate 4b. Has been. The width of the heating resistor 5 is set smaller than the width of the electrode layer 6 and the conductive layer 7. By making the width of the heating resistor 5 smaller than the width of the electrode layer 6 and the conductive layer 7, the electrical resistance of the heating resistor 5 is increased, and the control of the Joule heat generated in the heating resistor 5 portion is easy. can do.

  The heating resistor 5 is energized to the heating resistor 5 through the conductive layer 7 by detecting the abnormality of the circuit by the abnormality detector incorporated in the circuit together with the resistance temperature fuse. And since the electrical resistance of the heating resistor 5 is large, the temperature of the heating resistor 5 rises. Further, the temperature is transmitted to the thermal fuse element 3 through the first substrate 4a, and the fuse is blown when the temperature fuse element 3 reaches a predetermined temperature or higher. The heating resistor 5 is made of a material such as tungsten or platinum, for example.

  The thermal fuse element 3 is covered with a flux 8. The flux 8 is a material having excellent thermal conductivity, and is made of, for example, a material in which pine resin is dissolved in turpentine oil to form a paste, or a material such as zinc chloride. The flux 8 makes it easy to convey the temperature of the heating resistor 5 to the thermal fuse element 3. Then, the temperature difference between the temperature of the heating resistor 5 and the temperature fuse element 3 can be reduced.

  As described above, according to this embodiment, when the concave portion P is provided in the first substrate 4 a located on the uppermost surface of the base body 4 and the thermal fuse element 3 is blown out due to the temperature of the heating resistor 5. By flowing a part of the thermal fuse element 3 blown into the recess P, the current flowing through the electrode layer 6 can be effectively cut off, and the operating characteristics can be improved. As a result, it is possible to provide a resistance temperature fuse package and a resistance temperature fuse capable of improving the operating characteristics.

In addition, this invention is not limited to the above-mentioned form, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention. For example, in the pair of electrode layers 6 positioned on the first substrate 4a, the length of one electrode layer 6 and the length of the other electrode layer 6 are set to be different, and the heating resistor 5 is provided accordingly. May be changed. Further, a convex portion protruding from the inner wall surface of the concave portion P may be provided in the concave portion P. In addition, the convex part is set to the semicircle in planar view.

  Hereinafter, modifications of the present embodiment will be described. Note that, in the resistance temperature fuse 1 according to the modification of the present embodiment, the same portions as those of the resistance temperature fuse 1 according to the present embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.

<Modification>
FIG. 5 or 6 is a schematic perspective view of a resistance thermal fuse 1x according to a modification. In the uppermost layer of the substrate 4, a pair of groove portions Px may be formed at a position sandwiching the thermal fuse element 3 and the concave portion P in plan view. The groove portion Px is provided across the long side of the thermal fuse element 3 in plan view, and a part of the groove portion Px is continuously connected to the concave portion P.

  The groove part Px has a side length set to, for example, 1 mm or more and 11 mm or less in plan view. Moreover, the depth of the groove part Px is set to 0.02 mm or more and 2 mm or less, for example. The groove part Px functions as a heat insulating space and can make it difficult for heat from the heating resistor 5 to be transmitted.

  The groove part Px may penetrate through the first substrate 4 a located in the uppermost layer of the base body 4. And a part of upper surface of the 2nd board | substrate 4b located just under the 1st board | substrate 4a is exposed from the groove part Px.

  The groove portion Px is formed on both sides of the heating resistor 5 in a plan view, so that the heat generated from the heating resistor 5 is not transferred to the groove portion Px and the recess P, but on the region overlapping the heating resistor 5. It is possible to facilitate transmission toward the thermal fuse element 3 located.

  According to this modification, the heat generated by the heat generating resistor 5 can be easily transmitted to portions other than the concave portion P and the groove portion Px, in particular, to the first substrate 4 a located between the heat generating resistor 5 and the thermal fuse element 3. . Then, the heat transmitted to the first substrate 4a can be quickly transmitted to the thermal fuse element 3 positioned immediately above it, and the thermal fuse element 3 can be melted at a predetermined temperature. That is, it is possible to improve the operating characteristics by quickly transmitting the heat generated by the heating resistor 5 to the temperature fuse element 3 and the mounting surface R, and increasing the temperature rise of the temperature fuse element 3 and the mounting surface R quickly.

  In the resistance temperature fuse 1x according to this modification, the base body 4 has a three-layer structure, and the third substrate 4c is provided directly below the second substrate 4b. Furthermore, the cavity Py is provided in the third substrate 4c.

  The cavity Py is provided in the base body 4 and below the heating resistor 5 and is provided in a region overlapping the heating resistor 5 when seen in a plan view. The length of one side of the hollow portion Py when viewed in a plane is set to, for example, 2 mm and 5 mm or less. Moreover, the thickness of the cavity part Py is set to 0.1 mm or more and 1.5 mm or less, for example. The hollow portion Py functions as a heat insulating space, and can make it difficult for heat to be transmitted from the outside to the resistance temperature fuse. Note that the cavity Py may penetrate through the third substrate 4c. A part of the lower surface of the second substrate 4b is exposed.

When the resistance temperature fuse 1x according to this modification is provided in an external circuit, it is possible to make it difficult for heat transmitted from the external circuit to be transmitted to the second substrate 4b, and the temperature of the heating resistor 5 due to external temperature influences. Change can be suppressed. Then, by controlling the temperature of the heating resistor 5 to a desired temperature, the malfunction of the resistance temperature fuse 1x due to external temperature influence is suppressed, and further, when the heating resistor 5 of the resistance temperature fuse 1x generates heat. By making it difficult for heat to be transferred to an external circuit, the temperature rise characteristics of the resistance temperature fuse can be improved.

  Further, in the resistance temperature fuse 1x according to this modification, the electrode layer 6 is divided into two with a recess P interposed therebetween in a cross-sectional view, and an end 6x facing the recess P of the electrode layer 6 is formed. Is curved.

  Since the end portion 6x is curved, when the thermal fuse element 3 is melted, a part of the melted portion is easily attracted to the curved portion of the end portion 6x by surface tension. A part of the fused thermal fuse element 3 is pulled toward the end 6x on the surface of the first substrate 4a, so that the pair of electrode layers 6 facing each other can be electrically opened.

<Method of manufacturing resistance thermal fuse>
Here, a method of manufacturing the resistance temperature fuse 1 and the resistance temperature fuse package 2 shown in FIG. 1 will be described.

  First, the 1st board | substrate 4a and the 2nd board | substrate 4b which comprise the base | substrate 4 are prepared. When each substrate constituting the substrate 4 is made of, for example, an aluminum oxide sintered body, an organic binder, a plasticizer, a solvent, and the like are added to and mixed with raw material powders such as aluminum oxide, silicon oxide, magnesium oxide and calcium oxide. A green sheet is molded from the obtained mixture.

  Moreover, a high melting point metal powder such as tungsten or molybdenum is prepared, and an organic binder, a plasticizer, a solvent, or the like is added to and mixed with the powder to obtain a metal paste. Then, a metal paste is applied to the upper surface of the first substrate 4a in a green sheet state, and the electrode layer 6 is patterned.

  Next, a through hole is formed in the first substrate 4a in a green sheet state. The through hole functions as the recess P after the plurality of substrates are stacked.

  And the green sheet for 2nd board | substrates 4b is shape | molded similarly to the 1st board | substrate 4a. Further, a metal paste is applied to each of the upper surface and the lower surface of the second substrate 4b by, for example, screen printing to form the heating resistor 5, part of the electrode layer 6, and part of the conductive layer 7. Further, the conductive layer 7 is formed on the lower surface of the second substrate 4b by applying a metal paste using, for example, a screen printing method.

  Next, the first substrate 4a and the second substrate 4b are stacked and integrally fired at a temperature of about 1600 degrees. Further, necessary plating is performed on the surfaces of the thermal fuse element mounting portion, the circuit board mounting portion, and the support of the integrated base body 4. Here, the manufacturing method of the individual product for the resistance temperature fuse has been described. However, the manufacturing with a multi-piece sheet shape is preferable from the viewpoint of mass productivity and cost. In this way, the resistance temperature fuse package 2 can be manufactured.

  Next, the thermal fuse element 3 is mounted at a predetermined location on the first substrate 4 a located in the upper layer of the base 4. Then, the thermal fuse element 3 and the electrode layer 6 are electrically connected. Further, a flux 8 is formed on the substrate 4 so as to cover the thermal fuse element 3. In this way, the resistance temperature fuse 1 can be manufactured.

In addition, after mounting the thermal fuse element 3 at a predetermined position corresponding to each resistance thermal fuse of the resistance thermal fuse package 2 created in a multi-piece sheet shape, a flux is applied so as to cover the thermal fuse element 3 It is preferable from the viewpoint of mass productivity and cost to form 8 and then divide the multi-piece sheet into pieces.

DESCRIPTION OF SYMBOLS 1 Resistance thermal fuse 2 Resistance thermal fuse package 3 Thermal fuse element 4 Base | substrate 4a 1st board | substrate 4b 2nd board | substrate 5 Heating resistor 6 Electrode layer 7 Conductive layer 8 Flux P Concave part Px Groove part Py Cavity part R Mounting surface

Claims (5)

A substrate having a plurality of substrates laminated, and a substrate having a recess in the uppermost substrate,
A thermal fuse element on the base and provided over the recess;
Provided on the substrate, comprising a heating resistor which is formed in a region overlapping with the thermal fuse element in a plan perspective, a,
A resistance thermal fuse, wherein a cavity is provided in a region that overlaps the heating resistor in a plan view below the heating resistor in the base . The resistance thermal fuse of claim 1,
Between the base and the thermal fuse element, an electrode layer connected to the thermal fuse element is further provided,
The resistance thermal fuse, wherein the electrode layer contains a constituent material of the thermal fuse element. The resistance thermal fuse according to claim 1 or 2,
The resistance temperature fuse according to claim 1, wherein the electrode layer is divided into two parts with the recess interposed therebetween in a cross-sectional view, and an end portion of the electrode layer facing the recess is curved. A resistance temperature fuse according to any one of claims 1 to 3 ,
The resistance thermal fuse according to claim 1, wherein a pair of grooves are formed in the uppermost layer of the base body at a position sandwiching the thermal fuse element and the concave portion in plan view. A substrate having a mounting surface on which a thermal fuse element is mounted across both regions sandwiching the recess in plan view, having a recess in the substrate located in the uppermost layer and having a plurality of substrates stacked thereon,
A heating resistor provided in a region that overlaps with the mounting surface in a transparent manner in the base body ,
A resistance thermal fuse package, wherein a cavity portion is provided in a region that overlaps with the heating resistor in a plan view below the heating resistor in the base .

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