JP2007093453A - Surface-mounted temperature sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve higher temperature accuracy and response properties with less effect of thermal dissipation from the upper surface in a surface-mounted temperature sensor. <P>SOLUTION: The surface-mounted temperature sensor is provided with: an insulating substrate 10; a heat-sensitive resistor part 11 composed of a thermistor film formed on the surface of the insulating substrate 10; a film-like resistor part 12 which is formed on the surface of the insulating substrate 10 and whose one end and one end of the heat-sensitive resistor part 11 are electrically connected to each other; a first terminal electrode 13 electrically connected to the other end of the heat-sensitive resistor part 11; a second terminal electrode 14 electrically connected to the other end of the film-like resistor part 12; and a third terminal electrode 15 electrically connected to respective ends of the heat-sensitive resistor part 11 and the film-like resistor part 12. The heat-sensitive resistor part 11 is formed on the lower surface of the insulating substrate 10 to be the mounting surface. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a surface mount type temperature sensor effective for temperature detection and temperature compensation.

  Conventionally, as a thin film or thick film type thermistor used for temperature detection or temperature compensation, there is a two-terminal structure in which a thermistor portion is formed on an insulating substrate and terminal electrode portions are formed at both ends thereof. Are known. As a general temperature detection circuit using such a thermistor, as shown in an equivalent circuit of FIG. 9, an input terminal electrode 1, a resistor 2, an output terminal electrode 3, an NTC thermistor (Negative Temperature Coefficient Themistor) 4, and a ground A device in which terminal electrodes 5 are connected in series in this order is known.

The temperature detection circuit having such a configuration applies the voltage between the input terminal electrode 1 and the earth terminal electrode 5 and measures the voltage between the output terminal electrode 3 and the earth terminal electrode 5, thereby outputting the output voltage. Is converted into temperature, and a temperature change can be detected.
Conventionally, for example, Patent Document 1 proposes a thick film thermistor in which a thermistor thick film and a resistor thick film are formed on the upper surface (front surface) of an insulating substrate.

Japanese Patent Laid-Open No. 10-312916 (Claims, FIG. 7)

The following problems remain in the conventional technology.
In other words, conventionally, there has been a problem that the temperature accuracy and responsiveness of the thermistor thick film is reduced due to heat dissipation from the upper surface of the insulating substrate. In particular, in the case of overheat protection applications, when a heat-generating component such as an FET is a detection target, it is desired to further improve the detection temperature accuracy when thermal coupling with the heat-generating component is intended. .

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a surface-mounted temperature sensor that is less affected by heat dissipation from the upper surface, has higher temperature accuracy, and has excellent responsiveness.

  The present invention employs the following configuration in order to solve the above problems. That is, the surface mount type temperature sensor of the present invention is formed on the surface of the insulating substrate, the temperature sensitive resistor portion formed of the thermistor film formed on the surface of the insulating substrate, and the surface of the insulating substrate. A film resistance part in which one end of each is electrically connected to the temperature resistance part, a first terminal electrode electrically connected to the other end of the temperature sensitive resistance part, and the other of the film resistance part A second terminal electrode electrically connected to an end; and a third terminal electrode electrically connected to one end of each of the temperature-sensitive resistor portion and the film-like resistor portion, and the temperature-sensitive device. The resistance portion is formed on the lower surface of the insulating substrate serving as a mounting surface.

  In this surface mount type temperature sensor, since the temperature sensitive resistor portion is formed on the lower surface of the insulating substrate serving as the mounting surface, the temperature sensitive resistor portion is separated from the upper surface of the insulating substrate, and from the upper surface of the insulating substrate. The influence of heat dissipation can be reduced, and high temperature accuracy can be obtained. In addition, since the temperature-sensitive resistor portion is in contact with or close to the mounting substrate in the mounted state, direct heat conduction from the mounting substrate can be obtained and the responsiveness can be improved. In particular, there is a merit that the detection temperature accuracy can be improved in the case of heat coupling with the heat generating component when the heat generating component such as FET is a detection target in the case of overheating protection.

  In the surface mount type temperature sensor according to the present invention, the film-like resistance portion is formed at least on the upper surface of the insulating substrate. That is, in this surface mount type temperature sensor, the film-like resistance portion is formed on the upper surface of the insulating substrate opposite to the temperature-sensitive resistance portion, and is arranged on a different surface from the temperature-sensitive resistance portion. Compared with the case where the temperature-sensitive resistor portion and the film-like resistor portion are formed in the plane, the areas of the film-like resistor portion and the temperature-sensitive resistor portion on the surface of the insulating substrate can be set larger. In other words, the chip size of the insulating substrate can be reduced by the temperature-sensitive resistance portion and the film-like resistance portion having the same area, and the overall size can be reduced. In addition, the temperature-sensitive resistance portion is not easily affected by the heat generated by the film-like resistance portion, and the temperature accuracy can be further improved.

  The surface mount type temperature sensor of the present invention includes a fourth terminal electrode formed on at least one of the lower surface and the end surface of the insulating substrate and electrically insulated from the first to third terminal electrodes. It is characterized by that. That is, in this surface mount type temperature sensor, since the fourth terminal electrode is formed on at least one of the lower surface and the end surface of the insulating substrate, the fourth terminal electrode functions as a thermal coupling terminal, and higher heat Conductivity can be obtained. In this case, it is preferable that the fourth terminal electrode is formed of a material that has good thermal conductivity and can be soldered.

  Furthermore, in the surface mount type temperature sensor of the present invention, the fourth terminal electrode is formed on one end face side of the insulating substrate facing each other, and the first to third terminal electrodes are formed on the insulating substrate. And the area of the fourth terminal electrode is set larger than that of the first to third terminal electrodes. That is, in this surface mount type temperature sensor, since the fourth terminal electrode is formed in a wide area on the side opposite to the first to third terminal electrodes, the fourth terminal electrode side serving as a thermal coupling terminal is connected to an FET or the like. By mounting toward the heat-generating component side, heat can be easily received by the fourth terminal electrode having a large area, and heat can hardly be released by the first to third terminal electrodes having a small area. Can do.

  In the surface mount type temperature sensor of the present invention, a protective film is formed on the temperature-sensitive resistor portion, and the protective film is formed so that the entire lower surface of the insulating substrate is flush with the surface. It is characterized by being. That is, in this surface mount type temperature sensor, since the protective film is formed so that the entire lower surface of the insulating substrate is flush, the entire lower surface of the insulating substrate is in close contact with the mounting substrate when mounted. By fixing in a state, heat can be more efficiently conducted to the temperature-sensitive resistance portion on the lower surface.

The present invention has the following effects.
That is, according to the surface mount type temperature sensor according to the present invention, since the temperature sensitive resistor portion is formed on the lower surface of the insulating substrate serving as the mounting surface, the influence of heat dissipation from the upper surface of the insulating substrate can be reduced. In addition, it is possible to obtain direct heat conduction from the mounting substrate, and to obtain high temperature accuracy and responsiveness. Therefore, it is particularly suitable for overheating protection for heat-generating parts such as FETs.

  Hereinafter, a surface mount type temperature sensor according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.

  As shown in FIGS. 1 and 2, the surface mount type temperature sensor 110 according to the present embodiment is formed on an insulating substrate 10 such as an alumina substrate and an upper surface of the insulating substrate 10 to be a mounting surface. A temperature-sensitive resistor portion 11 made of a thermistor film; a temperature-sensitive resistor portion 11 formed on the lower surface of the insulating substrate 10; 11, a first terminal electrode 13 electrically connected to the other end of the electrode 11, a second terminal electrode 14 electrically connected to the other end of the film resistor 12, a temperature sensitive resistor 11 and a film A third terminal electrode 15 electrically connected to one end of each of the resistor parts 12; and a fourth terminal electrode 16 electrically insulated from the first to third terminal electrodes 13-15. Yes. That is, this surface-mount type temperature sensor is a voltage output type temperature sensor having effective three terminals including first to third terminal electrodes 13 to 15 and a thermal coupling terminal of the fourth terminal electrode 16.

  Examples of the temperature sensitive resistor 11 include NTC type, PTC type, and CTR type thermistors. In this embodiment, NTC type thermistors are used. The temperature-sensitive resistance portion 11 is formed of a thermistor material such as a Mn—Co—Cu-based material or a Mn—Co—Fe-based material in a rectangular shape. A first sub-film electrode portion 17a and a second sub-film electrode portion 17b are formed below the temperature-sensitive resistance portion 11 so as to face each other with a predetermined distance therebetween.

  Further, the first subfilm electrode portion 17 a and the first terminal electrode 13 are connected by a first wiring portion 13 a formed on the insulating substrate 10. The second subfilm electrode portion 17 b and the third terminal electrode 15 are connected by a second wiring portion 15 a formed on the insulating substrate 10. A third wiring portion 14 a connected to the second terminal electrode 14 is formed on the insulating substrate 10 so as to extend below one end portion of the film-like resistor portion 12. Furthermore, the second wiring portion 15 a is formed so that a part thereof extends below the other end portion of the film-like resistance portion 12. That is, in the equivalent circuit of FIG. 9, the first terminal electrode 13 is the ground terminal electrode 5, the second terminal electrode 14 is the input terminal electrode 1, and the third terminal electrode 15 is the output terminal. It functions as the electrode 3.

  The film-like resistance portion 12 is formed of a ruthenium oxide thick film material in a band shape. Moreover, the said 1st-4th terminal electrodes 13-16 have the structure which laminated | stacked the resin electrode containing Ag filler, Ni plating layer, and Sn plating layer in this order. The first and second sub-film electrode portions 17a, 17b and the first to third wiring portions 13a, 14a, 15a are made of an Ag-based or Ag / Pd-based electrode material.

As described above, the first to fourth terminal electrodes 13 to 16 are formed of a material having good thermal conductivity and solderable.
Further, the temperature-sensitive resistor portion 11 and the film-like resistor portion 12 are arranged with a predetermined interval therebetween. Furthermore, on the insulating substrate 10, as shown in FIG. 2, a glass material, a SiO ₂ sputtered film, a resin material (epoxy-based) or the like is provided so as to cover the temperature-sensitive resistance portion 11 and the film-like resistance portion 12. A protective film 18 is formed. As shown in FIG. 3, the protective film 18 is formed so that the entire lower surface of the insulating substrate 10 is flush. In the drawings other than FIGS. 2 and 3, the protective film 18 is omitted.

The first to fourth terminal electrodes 13 to 16 are provided on end surfaces facing each other of the insulating substrate 10, and are formed so as to extend to the upper surface and the lower surface of the insulating substrate 10. Yes.
In addition, the first terminal electrode 13 and the fourth terminal electrode 16 are disposed to face each other with the temperature-sensitive resistor portion 11 interposed therebetween, and the second terminal electrode 14 and the third terminal electrode. 15 are arranged opposite to each other with the film-like resistor 12 interposed therebetween.

  Next, a manufacturing method of the surface mount type temperature sensor 110 of the present embodiment will be described below. In the present embodiment, a case where a plurality of surface mount type temperature sensors 110 are collectively formed will be described.

  First, an insulating substrate 10 such as an alumina substrate having a large area capable of forming a plurality of surface mount type temperature sensors 110 is prepared, and an Ag-based or Ag / Pd-based electrode material is formed on one surface of the insulating substrate 10. A pattern is formed by screen printing for each region where the mounting type temperature sensor 110 is formed, and is fired at 850 ° C., whereby the first and second subfilm electrodes 17a and 17b and the first to third wiring portions 13a, 14a and 15a are formed.

  Next, a thick thermistor film is patterned in a predetermined region on the insulating substrate 10 to form the temperature-sensitive resistor portion 11. For example, a paste-like thick film thermistor material is patterned into a rectangular shape on the insulating substrate 10 using screen printing, and then baked at 850 ° C. to form the temperature-sensitive resistor portion 11. At this time, both ends of the temperature-sensitive resistor portion 11 are formed so as to be positioned on the first and second subfilm electrodes 17a and 17b.

Further, a ruthenium oxide-based paste-like resistance material is formed in a predetermined region on the insulating substrate 10 by screen printing and baked at 850 ° C., thereby forming the film-like resistance portion 12.
After the formation of the film-like resistance portion 12, a glass paste is applied on the insulating substrate 10 by screen printing and baked at 600 ° C. This glass paste functions as a part of the protective film 18.

Next, the thermistor characteristics of the temperature-sensitive resistor portion 11 are measured in advance, and laser trimming is performed on the film-like resistor portion 12 while measuring the resistance of the film-like resistor portion 12 so as to match the value. .
Thereafter, an epoxy resin is coated on the insulating substrate 10 by screen printing and cured at 200 ° C., thereby forming the protective film 18. At this time, the protective film 18 is formed by filling the unevenness so that the entire lower surface of the insulating substrate 10 is flush.

  Next, in this state, the flat insulating substrate 10 is primarily divided into strips, and an Ag filler-containing resin electrode made of Ag-based resin is formed in a predetermined region on the end surface of the insulating substrate 10. The first to fourth terminal electrodes 13 to 16 are formed by performing Ni plating and Sn plating in this order on the Ag filler-containing resin electrode on the end face of the insulating substrate 10 in a state of being divided into a second shape. Thus, the surface mount type temperature sensor 110 is manufactured.

  When mounting the surface mount type temperature sensor 110, as shown in FIG. 3, the lower surface on which the temperature sensitive resistor portion 11 is formed is mounted on the mounting substrate P as a mounting surface, and the first to fourth terminal electrodes are mounted. 13 to 16 are bonded to the mounting substrate P by solder H and electrically connected. At the time of this mounting, the fourth terminal electrode 16 that is a thermal coupling terminal is fixed to the mounting substrate P toward the heat generating component F such as an FET, so that the fourth terminal electrode 16 is attached to the heat generating component F. The temperature accuracy and responsiveness are improved.

  As described above, in this embodiment, since the temperature-sensitive resistor portion 11 is formed on the lower surface of the insulating substrate 10 serving as a mounting surface, the temperature-sensitive resistor portion 11 is separated from the upper surface of the insulating substrate 10, so The influence of heat dissipation from the upper surface of the substrate 10 can be reduced, and high temperature accuracy can be obtained. In addition, since the temperature sensitive resistor portion 11 is in contact with or close to the mounting substrate P in the mounted state, direct heat conduction from the mounting substrate P can be obtained and responsiveness can be improved. In particular, there is a merit that the detection temperature accuracy can be improved in the case of heat coupling with the heat generating component when the heat generating component such as FET is a detection target in the case of overheating protection.

Moreover, since the 4th terminal electrode 16 is formed in the end surface and lower surface of the insulating board | substrate 10, the 4th terminal electrode 16 functions as a thermal coupling terminal, and can obtain higher thermal conductivity.
Furthermore, since the protective film 18 is formed so that the entire lower surface of the insulating substrate 10 is flush, the entire lower surface of the insulating substrate 10 is fixed in close contact with the mounting substrate P when mounted. This makes it possible to more efficiently conduct heat to the temperature-sensitive resistance portion 11 on the lower surface.

  Next, a second embodiment of the surface mount type temperature sensor according to the present invention will be described below with reference to FIGS. In the following embodiments, the same constituent elements described in the above embodiments are denoted by the same reference numerals, and description thereof is omitted.

  The difference between the second embodiment and the first embodiment is that, in the first embodiment, the film-like resistance portion 12 is formed on the lower surface of the insulating substrate 10 that is flush with the temperature-sensitive resistance portion 11. On the other hand, the surface-mounted temperature sensor 120 of the second embodiment is that the film-like resistance portion 12 is formed on the upper surface of the insulating substrate 10 as shown in FIGS. That is, in the surface-mounted temperature sensor 120 of the second embodiment, the film-like resistance portion 12 is formed on the upper surface of the insulating substrate 10 on the side opposite to the temperature-sensitive resistance portion 11 and is separate from the temperature-sensitive resistance portion 11. It is arranged on the surface.

  Therefore, in the surface mount type temperature sensor 120 of the second embodiment, the film resistance on the surface of the insulating substrate 10 is compared with the case where the temperature sensitive resistance portion 11 and the film resistance portion 12 are formed in the same plane. The area of the part 12 and the temperature-sensitive resistor part 11 can be set large. In other words, the chip size of the insulating substrate 10 can be reduced by the temperature-sensitive resistor portion 11 and the film-like resistor portion 12 having the same area, and the overall size can be reduced. In addition, the temperature-sensitive resistance portion 11 is less susceptible to the heat generated by the film-like resistance portion 12, and the temperature accuracy can be further improved.

  Next, a third embodiment of the surface mount type temperature sensor according to the present invention will be described below with reference to FIGS.

  The difference between the third embodiment and the second embodiment is that in the second embodiment, the fourth terminal electrode 16 and the third terminal electrode 15 are formed on the same end face side of the insulating substrate 10 with the same area. In contrast, in the surface mount type temperature sensor 130 of the third embodiment, as shown in FIGS. 7 and 8, the fourth terminal electrode 36 is on one end face side of the insulating substrate 10 facing each other. The first to third terminal electrodes 33 to 35 are formed on the opposite end surfaces of the insulating substrate 10, and the area of the fourth terminal electrode 36 is the first to third terminal electrodes 33. It is the point set larger than -35.

That is, in the surface mount type temperature sensor 130 of the third embodiment, the fourth terminal electrode 36 is formed over the entire length of one end surface of the insulating substrate 10. Further, the first wiring portion 33a that connects the first terminal electrode 33 and the first subfilm electrode portion 17a, and the second wiring that connects the third terminal electrode 35 and the second subfilm electrode portion 17b. The wiring part 35a is a meander-shaped thin line part that is folded back in plural.
When the surface mount type temperature sensor 130 is mounted, the fourth terminal electrode 36 is directed and fixed to the heat generating component F side such as an FET.

  Thus, in 3rd Embodiment, since the 4th terminal electrode 36 is formed in the wide area on the opposite side to the 1st-3rd terminal electrodes 33-35, the 4th terminal electrode 36 used as a thermal coupling terminal is formed. By mounting the side facing the heat-generating component F side such as an FET, the fourth terminal electrode 36 having a large area can easily receive heat, and the first to third terminal electrodes 33 to 33 having a small area. 35 makes it difficult to release heat. Further, since the first wiring portion 33a and the second wiring portion 35a are meander-shaped thin wire portions, the outflow of heat from the signal line, that is, the heat is transferred to the first wiring portion 33a and the second wiring portion 35a. It is possible to suppress the diffusion to the first terminal electrode 33 and the third terminal electrode 35 via the wiring portion 35a.

  The technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

For example, in each of the above embodiments, the temperature-sensitive resistance portion of the thick film thermistor is formed using a screen printing method or the like. However, the thin film thermistor is patterned by sputtering on the insulating substrate 10 by photolithography. The temperature sensitive resistor portion 11 may be formed.
Further, the film-like resistance portion 12 may be formed of a resistance thin film material such as a NiCr film or a Cr film.

It is a bottom view which shows the surface mounted type temperature sensor of 1st Embodiment which concerns on this invention. It is the perspective view seen from the lower surface side which shows the surface mount type temperature sensor of 1st Embodiment. It is a schematic sectional drawing of the mounting state which shows the surface mount type temperature sensor of 1st Embodiment. It is the perspective view seen from the upper surface side which shows the surface mount type temperature sensor of 2nd Embodiment which concerns on this invention. It is a bottom view which shows the surface mount type temperature sensor of 2nd Embodiment. It is a top view which shows the surface mount type temperature sensor of 2nd Embodiment. It is the perspective view seen from the upper surface side which shows the surface mount type temperature sensor of 3rd Embodiment which concerns on this invention. It is a bottom view which shows the surface mount type temperature sensor of 3rd Embodiment. It is an equivalent circuit diagram showing a general temperature detection circuit using a thermistor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Insulating substrate, 11 ... Temperature sensitive resistance part, 12 ... Film-like resistance part, 13, 33 ... 1st terminal electrode, 14, 34 ... 2nd terminal electrode, 15, 35 ... 3rd terminal electrode, 16, 36 ... fourth terminal electrode, 110, 120, 130 ... surface mount type temperature sensor

Claims (5)

An insulating substrate;
A temperature-sensitive resistor portion made of a thermistor film formed on the surface of the insulating substrate;
A film-like resistor portion formed on the surface of the insulating substrate and electrically connected at one end to the temperature-sensitive resistor portion;
A first terminal electrode electrically connected to the other end of the temperature sensitive resistor;
A second terminal electrode electrically connected to the other end of the film resistor,
A third terminal electrode electrically connected to one end of each of the temperature-sensitive resistance portion and the film-like resistance portion, and
The surface-mount type temperature sensor, wherein the temperature-sensitive resistance portion is formed on a lower surface of the insulating substrate serving as a mounting surface. The surface mount type temperature sensor according to claim 1,
The surface-mount type temperature sensor, wherein the film-like resistance portion is formed on an upper surface of the insulating substrate. In the surface mount type temperature sensor according to claim 1 or 2,
A surface-mount type temperature sensor comprising a fourth terminal electrode formed on at least one of a lower surface and an end surface of the insulating substrate and electrically insulated from the first to third terminal electrodes. In the surface mount type temperature sensor according to claim 3,
The fourth terminal electrode is formed on one end face side of the insulating substrate facing each other;
The first to third terminal electrodes are formed on the other end face sides of the insulating substrate facing each other;
The surface mount type temperature sensor, wherein an area of the fourth terminal electrode is set larger than that of the first to third terminal electrodes. In the surface mount type temperature sensor according to any one of claims 1 to 4,
A protective film is formed on the temperature-sensitive resistor portion,
The surface mount type temperature sensor, wherein the protective film is formed so that the entire lower surface of the insulating substrate is flush.

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