JP6515569B2 - Temperature sensor - Google Patents

Description

  The present invention relates to a temperature sensor which is formed by sealing a heat-sensitive element portion with a resin in a case, which is excellent in responsiveness and in which variation in heat dissipation constant is small.

  In general, a temperature sensor using a thermistor element is used in a control system of a home appliance such as an air conditioner, a refrigerator, a washing machine or the like and an automobile control mechanism such as an exhaust gas recirculation (EGR: Exhaust Gas Recirculation). In these temperature sensors, since it is necessary to isolate the thermistor element from an external liquid or gas, the thermistor element is housed in a case of metal or resin and sealed by casting with a resin. For example, Patent Document 1 describes a temperature sensor in which a thermosensitive element is housed in a bottomed case and the periphery is filled with a resin.

  In such a temperature sensor, as shown in FIG. 5, a chip-like or flake-like thermistor element 102 in which one end of a lead wire 3 is connected to a pair of electrodes 102a is housed in a case 5 with a bottom. The resin 4 is filled in the case 5.

JP 2003-240642 A

The following problems remain in the above-mentioned prior art.
In the conventional temperature sensor, when the chip-like or flake-like thermistor element 102 is disposed in the case 5 and sealed with the resin 4, the position of the thermistor element 102 is made constant with respect to the bottom surface in the case 5 There is a problem that the distance between the thermistor element 102 after resin sealing and the bottom of the case 5 varies. As described above, when the distance between the thermistor element 102 and the bottom surface of the case 5 varies, the response time and the heat dissipation constant may vary.

  The present invention is made in view of the above-mentioned subject, and an object of the present invention is to provide a temperature sensor which can control variation of a response or a heat dissipation constant.

The present invention adopts the following configuration in order to solve the problems. That is, in the temperature sensor according to the first aspect of the present invention, the heat sensitive element, the pair of lead wires whose one end is connected to the heat sensitive element, and the other end of the lead wire are disposed outside and a bottom of the case that the part housing is sealed therein with a resin, the thermosensitive element section, an insulating film, and the insulating thermistors portion formed by the thermistor material disposed on the surface of the film a pair of electrodes formed on the thermistors portion, one end pair of patterned on a surface of the insulating film other end connected to the pair of lead wires with being connected to said pair of electrodes and a pattern electrode, the surface side or back side of the portion thermistors portion is formed of an insulating film, in a state where the surface contact with the surface of the said case, the heat sensitive element portion is sealed with the resin Being And features.

In this temperature sensor, the front side or back side of the portion thermistors portion of the insulating film is formed is, in a state where the surface contact with the surface of the case, since the heat sensitive element is sealed with a resin, the heat-sensitive element The position of the part is fixed to the surface in the case, and the variation of the response time and the heat dissipation constant is suppressed. In addition, by being in surface contact with the surface in the case the surface side or back side of the thermistors portion directly heat is transferred from the case to the thermistors portion, high responsiveness can be obtained.

In the temperature sensor according to a second aspect of the present invention, in the first aspect, the insulating film is formed in a band shape, and the other ends of the pair of pattern electrodes are disposed at different ends of the insulating film. the thermistors section, the conjunction is arranged in a central portion of the insulating film, the insulating film, characterized in that both ends thereof bent is a U-shaped cross-section.
That is, in this temperature sensor, since the insulating film is bent at its both end portions to be U-shaped in cross section, the heat sensitive element portion is in the case with the center portion of the insulating film facing the surface in the case. by inserting can be resin-sealed in a state where the thermistors portion is pressed by the spring resistance of the surface insulating film in case the central portion is provided, it is possible to obtain high adhesion. Further, it is possible to release the connection position of the lead wire from the thermistors portion of the surface of the case, it is possible to suppress the thus radiated to the outside through a lead wire.

The temperature sensor according to the third invention is characterized in that in the second invention, the distance between the bent end portions of the insulating film is set to be substantially the same as the inner diameter of the case.
That is, in this temperature sensor, since the distance between the bent ends of the insulating film is set to be substantially the same as the inner diameter of the case, both ends of the bent insulating film are guided to the inner circumferential surface of the case has been by being inserted into the case, it is positioned in the radial direction, it is possible to easily disposed in the center in the bottom surface of the case the thermistors portion.

The temperature sensor according to a fourth aspect of the present invention is the temperature sensor according to any of the first to third aspects, wherein the bottom surface in the case is concave and the insulating film is in close contact with the bottom surface. The element portion is sealed in the resin.
That is, in this temperature sensor, since the heat sensitive element portion is sealed in the resin in a state where the flexible insulating film is bent along and in close contact with the bottom in the case, the heat sensitive element is the bottom of the concave surface The parts can be placed in close contact.
In the temperature sensor according to a fifth aspect of the present invention, in any one of the first to fourth aspects, the thermistor portion is a thin film thermistor portion patterned on the surface of the insulating film with a thermistor material, The electrodes are characterized in that they are a pair of comb-shaped electrodes having a plurality of combs on at least one of the upper and lower sides of the thin film thermistor portion and patterned to be opposed to each other.

According to the present invention, the following effects are achieved.
That is, according to the temperature sensor according to the present invention, the surface side or back side of the portion thermistors portion of the insulating film is formed, the heat sensitive element is sealed with a resin in a state of surface contact with the surface of the case Thus, variations in response time and heat dissipation constant can be suppressed, and high response can be obtained. Therefore, the present invention has excellent response as well as small variation in response time etc. It is used particularly for control systems of home appliances such as air conditioners, refrigerators, washing machines etc. and exhaust gas recirculation etc. It is suitable as a temperature sensor.

It is a sectional view showing a 1st embodiment of a temperature sensor concerning the present invention. In 1st Embodiment, it is the top view and AA sectional drawing which show a thermosensitive element part. It is a sectional view showing a 2nd embodiment of a temperature sensor concerning the present invention. It is sectional drawing which shows 3rd Embodiment of the temperature sensor which concerns on this invention. It is a sectional view showing the conventional example of the temperature sensor concerning the present invention.

  Hereinafter, a first embodiment of a temperature sensor according to the present invention will be described with reference to FIGS. 1 and 2. In addition, in each drawing used for the following description, in order to make each member a recognizable or easily recognizable size, the scale is appropriately changed.

As shown in FIG. 1 and FIG. 2, the temperature sensor 1 of the present embodiment includes the heat sensitive element portion 2, a pair of lead wires 3 whose one end is connected to the heat sensitive element portion 2, and the other end side of the lead wires 3. It has the bottomed case 5 which encloses the thermosensitive element part 2 inside with resin 4 in the state arrange | positioned outside, and is accommodated.
The heat sensing element unit 2 has an insulating film 6, a thin film thermistor unit 7 (thermistor unit) patterned with a thermistor material on the surface of the insulating film 6, and a plurality of combs 8a on the thin film thermistor unit 7. And a pair of comb-shaped electrodes 8 (electrodes) pattern-formed facing each other, and one end is connected to the pair of comb-shaped electrodes 8 and the other end is connected to the pair of lead wires 3. And a pair of patterned electrodes 9 patterned on the surface of the substrate.

Note that FIG. 1 schematically shows the structure of the heat-sensitive element unit 2.
The said insulating film 6 is formed in strip shape, as shown in FIG. The insulating film 6 is formed of, for example, a polyimide resin sheet having a thickness of 7.5 to 125 μm.
Further, the other ends of the pair of pattern electrodes 9 are disposed at different ends of the insulating film 6. Furthermore, the thin film thermistor unit 7 is disposed at the central portion of the insulating film 6.

The thermosensitive element portion 2 is sealed with the resin 4 in a state where the back surface side of the portion of the insulating film 6 where the thin film thermistor portion 7 is formed is in surface contact with the bottom surface in the case 5.
That is, the casting resin 4 is injected into the case 5 in a state where the back surface of the heat sensitive element portion 2 is in close contact with the bottom surface of the case 5 and filled. It is fixed accurately.
The heat sensing element portion 2 may be spot-welded, bonded with a double-sided tape or the like to the bottom surface of the case 5 and adhesively attached, and temporarily placed, and then the resin 4 may be injected for casting.

  The pair of pattern electrodes 9 is formed of, for example, a laminated metal film of a NiCr film and a Pt film, and has comb-shaped electrode portions (combs 8a) of a comb-shaped pattern disposed in an opposing state. The comb electrode portions of these pattern electrodes 9 are arranged to extend along the extension direction of the strip-shaped insulating film 6. Further, one end of the lead wire 3 is bonded to the end of the pair of pattern electrodes 9 by a solder material, a welding or a conductive adhesive.

The thin film thermistor unit 7 is a thin film thermistor material made of a nitride such as TiAlN having a film thickness of 100 to 1000 nm, for example, and is formed in a rectangular shape in the center of the surface of the insulating film 6.
In particular, the thin film thermistor unit 7 of the present embodiment has a general formula: Ti _x Al _y N _z (0.70 ≦ y / (x + y) ≦ 0.95, 0.4 ≦ z ≦ 0.5, x + y + z = 1) The crystal structure is a hexagonal wurtzite type single phase.

The case 5 is formed of a metal such as stainless steel or aluminum or a resin such as PP (polypropylene).
The resin 4 is, for example, an epoxy resin or the like.
The lead wire 3 is, for example, an insulation coated electric wire having a core wire, but a lead frame or the like may be adopted.

Further, the temperature sensor 1 of the present embodiment is provided with a protective film 10 patterned on the surface of the insulating film 6 so as to cover the thin film thermistor portion 7. In addition, you may adhere | attach the insulating protective sheet which covers the protective film 10 of the surface of the insulating film 6. FIG.
The protective film 10 is an insulating resin film or the like, and for example, a polyimide film having a thickness of 20 μm is employed. The protective film 10 is patterned in a rectangular shape so as to cover the comb portion 8 a together with the thin film thermistor portion 7.

  As described above, in the temperature sensor 1 of the present embodiment, the thermosensitive element portion 2 is made of resin 4 in a state where the back surface side of the portion of the insulating film 6 where the thin film thermistor portion 7 is formed is in surface contact with the bottom surface in the case 5 Since it is sealed, the position of the heat sensing element portion 2 is fixed to the bottom surface in the case 5, and variations in response time and heat dissipation constant are suppressed. Further, by being in surface contact with the bottom surface in the case 5 on the back surface side of the thin film thermistor unit 7, heat is directly transmitted from the case 5 to the entire surface of the thin film thermistor unit 7, and high responsiveness can be obtained.

  Next, second and third embodiments of the temperature sensor according to the present invention will be described below with reference to FIGS. 3 to 4. In the following description of each embodiment, the same components as those described in the above embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

  The second embodiment differs from the first embodiment in that in the first embodiment, the insulating film 6 is formed in a linearly extending strip shape, whereas the temperature sensor 21 of the second embodiment is different from the first embodiment. The point is that, as shown in FIG. 3, the insulating film 26 is bent at its both end portions to be U-shaped in cross section. That is, the insulating film 26 is formed longer than the insulating film 6 of the first embodiment, and the end of the pattern electrode to which the lead wire 3 is connected is disposed in the bent portion of both ends .

Further, in the second embodiment, the distance between the bent end portions of the insulating film 26 is set to be substantially the same as the inner diameter of the case 5.
That is, in the second embodiment, the heat sensing element portion 2 has a U-shaped cross section, and can be inserted in the case 5 with the center portion facing the bottom surface in the case 5 (slightly smaller than the inner diameter of the case 5 Set to a small width).

  As described above, in the temperature sensor 21 according to the second embodiment, both ends of the insulating film 26 are bent to form a U-shaped cross section. The heat-sensitive element portion 2 is inserted into the case 5 so that resin sealing is performed in a state where the central portion in which the thin film thermistor portion 7 is formed is pressed against the bottom of the case 5 by the spring property of the insulating film 26 It is possible to obtain high adhesion.

Further, since the connection position of the lead wire 3 can be separated from the thin film thermistor portion 7 on the bottom surface in the case 5, the heat radiation to the outside through the lead wire 3 can be suppressed.
Furthermore, since the distance between the bent ends of the insulating film 26 is set to be substantially the same as the inner diameter of the case 5, both ends of the bent insulating film 26 are guided to the inner circumferential surface of the case By being inserted into the case 5, positioning in the radial direction can be performed, and the thin film thermistor portion 7 can be easily disposed at the center of the bottom surface in the case 5.

  Next, the difference between the third embodiment and the first embodiment is that the bottom of the case 5 has a flat shape in the first embodiment, while the temperature sensor 31 of the third embodiment does not have the shape shown in FIG. As shown in the drawing, the bottom of the case 35 has a convex shape. That is, in the third embodiment, the heat sensing element portion 2 is sealed with the resin 4 in a state in which the bottom surface in the case 35 is concave and the insulating film 6 is in close contact along the bottom surface in the case 35 .

  As described above, in the temperature sensor 31 according to the third embodiment, the thermosensitive element portion 2 is a flexible thermistor element, and the flexible insulating film 6 is bent along the bottom surface in the case 35 and is in close contact with the thermosensitive element portion 2 Is sealed in the resin 4, the heat sensing element portion 2 can be disposed in close contact even with the bottom surface of the concave surface.

About the Example of this invention produced based on the said 1st Embodiment, it measured about the thermal time constant and heat dissipation constant. In addition, it measured similarly about the conventional temperature sensor which used the chip-like thermistor element as a comparative example.
As a result, in the comparative example, the thermal time constant is 5 to 7 seconds, but in the example of the present invention, it is about 2 to 3 and 3.5 seconds, and the variation is also reduced to 1/4. did.
In addition, the heat dissipation constant after attachment, when attached to an object having a relatively large heat capacity, had similar variations between the comparative example and the embodiment of the present invention, but an object having a relatively small heat capacity In the case of the comparative example having a variation of 0.2 mW / .degree. C., the example of the present invention had a variation of 0.05 mW / .degree.

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

  For example, in the above embodiments, the thermosensitive element portion is sealed with resin in a state in which the back surface side of the portion where the thin film thermistor portion of the insulating film is formed is in surface contact with the bottom surface in the case. And the heat-sensitive element portion is sealed with resin in a state where the surface side of the portion where the thin film thermistor portion of the insulating film is formed is in surface contact with the bottom surface in the case It does not matter.

1, 21, 31 ... temperature sensor, 2 ... thermal sensing element portion, 3 ... lead wire, 4 ... resin, 5, 35 ... case, 6, 26 ... insulating film, 7 ... thin film thermistor portion (thermistor portion) , 8 ... Comb-shaped electrode (electrode) , 8a ... comb portion, 9 ... pattern electrode

Claims (4)

A thermosensitive element unit,
A pair of lead wires whose one end is connected to the heat sensitive element portion;
And a bottomed case for sealing the heat sensing element portion inside with the resin and housing the other end side of the lead wire to the outside;
The thermosensitive element portion is connected to an insulating film, a thermistor portion provided on the surface of the insulating film and formed of a thermistor material, a pair of electrodes formed on the thermistor portion, and one end connected to the pair of electrodes And a pair of patterned electrodes, the other end of which is connected to the pair of lead wires and patterned on the surface of the insulating film;
The thermosensitive element portion is sealed with the resin in a state in which the front surface side or the back surface side of the portion of the insulating film on which the thermistor portion is formed is in surface contact with the surface in the case ;
The insulating film is formed in a band shape,
The other ends of the pair of pattern electrodes are disposed at different ends of the insulating film,
The temperature sensor according to claim 1, wherein the thermistor portion is disposed at a central portion of the insulating film, and the insulating film is bent at both ends thereof to have a U-shaped cross section . In the temperature sensor according to claim 1 ,
A temperature sensor, wherein a distance between the bent end portions of the insulating film is set to be substantially the same as an inner diameter of the case. In the temperature sensor according to claim 1 or 2 ,
The bottom surface in the case is a concave surface,
The temperature sensor, wherein the heat-sensitive element portion is sealed in the resin in a state where the insulating film is in close contact with the bottom surface. The temperature sensor according to any one of claims 1 to 3 .
The thermistor portion is a thin film thermistor portion patterned with a thermistor material on the surface of the insulating film,
The temperature sensor according to claim 1, wherein the pair of electrodes are a pair of comb-shaped electrodes having a plurality of combs on at least one of the upper and lower sides of the thin film thermistor portion and patterned to face each other.

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