JPH113805A - Positive temperature coefficient thermistor - Google Patents
Positive temperature coefficient thermistorInfo
- Publication number
- JPH113805A JPH113805A JP15501397A JP15501397A JPH113805A JP H113805 A JPH113805 A JP H113805A JP 15501397 A JP15501397 A JP 15501397A JP 15501397 A JP15501397 A JP 15501397A JP H113805 A JPH113805 A JP H113805A
- Authority
- JP
- Japan
- Prior art keywords
- temperature coefficient
- positive temperature
- coefficient thermistor
- thermistor
- positive
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、正特性サーミスタ
に関し、特に、過電流保護回路、消磁回路、モータ起動
回路等の回路に用いられ、フラッシュ耐圧の大きな正特
性サーミスタに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive temperature coefficient thermistor, and more particularly to a positive temperature coefficient thermistor used in circuits such as an overcurrent protection circuit, a demagnetizing circuit, and a motor starting circuit, and having a high flash breakdown voltage.
【０００２】[0002]
【従来の技術】従来の正特性サーミスタ３１は、図９に
示されるように、板状のサーミスタ素体３２の両主面に
オーミック性の電極３３、３４が形成されたものであ
る。2. Description of the Related Art A conventional positive temperature coefficient thermistor 31, as shown in FIG. 9, has ohmic electrodes 33 and 34 formed on both main surfaces of a plate-like thermistor body 32.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、従来の
正特性サーミスタ３１に電圧を印加すると、印加直後は
正特性サーミスタ３１が低抵抗であるため、突入電流が
多く流れて、ジュール熱によって正特性サーミスタ３１
が高温になり主面と略平行な面で割れる層状割れという
現象が発生する（正特性サーミスタに突入電流を流した
とき、正特性サーミスタが層状割れに至る直前の電圧を
フラッシュ耐圧と呼ぶ）。特に、正特性サーミスタ３１
を小型化すると、フラッシュ耐圧が小さくなるという問
題点を有していた。However, when a voltage is applied to the conventional positive-characteristic thermistor 31, immediately after the voltage is applied, since the positive-characteristic thermistor 31 has a low resistance, a large amount of inrush current flows, and the positive-characteristic thermistor 31 is caused by Joule heat. 31
Becomes high temperature, causing a phenomenon of layered cracking that splits on a plane substantially parallel to the main surface (the voltage immediately before the positive characteristic thermistor reaches the layered crack when an inrush current flows through the positive characteristic thermistor is called flash breakdown voltage). In particular, the positive characteristic thermistor 31
There is a problem that when the size is reduced, the flash breakdown voltage is reduced.
【０００４】本発明の目的は、上述の問題点を解消すべ
くなされたもので、フラッシュ耐圧が大きい正特性サー
ミスタを提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a positive temperature coefficient thermistor having a large flash breakdown voltage.
【０００５】[0005]
【課題を解決するための手段】上記目的を達成するため
に、本発明の正特性サーミスタ素体においては、正の抵
抗温度特性を有するセラミック体の厚みがその主面の周
縁部の一部が中央部に比べて厚いサーミスタ素体の両主
面に電極が形成されている。あるいは、本発明による正
特性サーミスタ素体は、前記正特性サーミスタ素体の両
主面の周縁部の一部が中央部に比べて凸状である。In order to achieve the above object, in the positive temperature coefficient thermistor element of the present invention, the thickness of the ceramic body having a positive resistance temperature characteristic is such that a part of the peripheral portion of the main surface thereof is formed. Electrodes are formed on both main surfaces of the thermistor body that is thicker than the central part. Alternatively, in the positive temperature coefficient thermistor body according to the present invention, a part of a peripheral portion of both main surfaces of the positive temperature coefficient thermistor body is more convex than a center portion.
【０００６】さらに、前記正特性サーミスタ素体の周縁
の角部が丸みを帯びていることが好ましい。さらに、前
記正特性サーミスタ素体の周縁部の凸部にこのセラミッ
ク体の厚み方向に主面側から溝が形成されていることが
好ましい。また、前記電極は下層電極と上層電極からな
り、下層電極が前記正特性サーミスタ素体の両主面全面
に形成されていること。さらに、前記上層電極はその周
縁部で下層電極が露出するように前記下層電極より小さ
な平面積からなることが好ましい。また、前記上層電極
は前記正特性サーミスタ素体の凸状の周縁部を除く中央
部に対応する両主面に形成されている。Further, it is preferable that the corner of the peripheral edge of the positive temperature coefficient thermistor element is rounded. Further, it is preferable that a groove is formed in a convex portion of a peripheral portion of the positive temperature coefficient thermistor body from a main surface side in a thickness direction of the ceramic body. Further, the electrode comprises a lower electrode and an upper electrode, and the lower electrode is formed over both main surfaces of the positive temperature coefficient thermistor body. Further, it is preferable that the upper layer electrode has a smaller plane area than the lower layer electrode such that the lower layer electrode is exposed at a peripheral portion thereof. Further, the upper electrode is formed on both main surfaces corresponding to a central portion of the positive temperature coefficient thermistor element body excluding a convex peripheral portion.
【０００７】これにより、正特性サーミスタのフラッシ
ュ耐圧及びＰmax を向上させることができるものであ
る。As a result, the flash breakdown voltage and Pmax of the PTC thermistor can be improved.
【０００８】[0008]
【発明の実施の形態】本発明による第１の実施の形態の
正特性サーミスタについて、図１、図２に基づいて説明
する。正特性サーミスタ１は、正特性サーミスタ素体２
の両主面に、オーミック性の例えばＮｉ、Ｉｎ−Ｇａ、
Ａｌ、またはＡｇを主成分とする電極３、４が形成され
たものである。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A PTC thermistor according to a first embodiment of the present invention will be described with reference to FIGS. The positive characteristic thermistor 1 is composed of a positive characteristic thermistor body 2
Ohmic properties such as Ni, In-Ga,
Electrodes 3 and 4 mainly composed of Al or Ag are formed.
【０００９】正特性サーミスタ素体２は、チタン酸バリ
ウムを主成分とする正特性サーミスタ用セラミック原料
を、成形、焼結した正の抵抗温度特性有する略円板状の
セラミック体からなり、セラミック体の厚みが、その両
主面の異なる周縁部の一部に、中央部に比べて厚い凸状
部５、６、７、８が形成されたものである。The positive temperature coefficient thermistor body 2 is formed of a ceramic material for a positive temperature coefficient thermistor containing barium titanate as a main component and formed and sintered into a substantially disk-shaped ceramic body having a positive resistance temperature characteristic. Is formed on a part of the peripheral portion where the two main surfaces are different from each other, and convex portions 5, 6, 7, 8 thicker than the central portion are formed.
【００１０】本発明による第２の実施の形態の正特性サ
ーミスタについて、図３に基づいて説明する。但し、前
述の実施の形態と同様部分については、同様の符号を付
し、詳細な説明を省略する。A PTC thermistor according to a second embodiment of the present invention will be described with reference to FIG. However, the same parts as those in the above-described embodiment are denoted by the same reference numerals, and detailed description is omitted.
【００１１】正特性サーミスタ１ａは、正特性サーミス
タ素体２ａの両主面にオーミック性の電極３ａ、４ａが
形成されたものである。正特性サーミスタ素体２ａは、
略矩形状のセラミック体からなり、セラミック体の厚み
が、その両主面の対向する周縁部の一部に、中央部に比
べて厚い凸状部５ａ、６ａ、７ａ、８ａが形成されたも
のである。The positive temperature coefficient thermistor 1a is obtained by forming ohmic electrodes 3a, 4a on both main surfaces of a positive temperature coefficient thermistor body 2a. The positive characteristic thermistor body 2a is
It is made of a substantially rectangular ceramic body, and the thickness of the ceramic body is such that convex portions 5a, 6a, 7a, 8a that are thicker than the central portion are formed on a part of the peripheral edge portions facing both main surfaces. It is.
【００１２】なお、第１および第２の実施の形態の正特
性サーミスタ素体２、２ａの凸状部５〜８、５ａ〜８ａ
は、両主面において互いに対向しない位置、および互い
に対向する位置のものを示したが、これに限定されるも
のではなく、両主面の任意な位置に設けられてもよい。
また、凸状部の数についても上述した実施の形態に限定
されるものではない。Incidentally, the convex portions 5 to 8, 5a to 8a of the positive temperature coefficient thermistor bodies 2, 2a of the first and second embodiments.
Are shown at positions that do not face each other and at positions that face each other on both main surfaces. However, the present invention is not limited to this, and may be provided at any position on both main surfaces.
Also, the number of convex portions is not limited to the above-described embodiment.
【００１３】本発明による第３の他の実施の形態の正特
性サーミスタについて、図４に基づいて説明する。但
し、前述の実施の形態と同様部分については、同様の符
号を付し、詳細な説明を省略する。A positive temperature coefficient thermistor according to a third embodiment of the present invention will be described with reference to FIG. However, the same parts as those in the above-described embodiment are denoted by the same reference numerals, and detailed description is omitted.
【００１４】正特性サーミスタ１ｂは、正特性サーミス
タ素体２ｂの両主面にオーミック性の電極３ｂ、４ｂが
形成されたものである。正特性サーミスタ素体２ｂは、
略円形状のセラミック体からなり、セラミック体の厚み
が、その両主面の対向する周縁部に、切り欠き９、１０
を除いて中央部に比べて厚い凸状部５ｂ、７ｂが形成さ
れたものである。The positive temperature coefficient thermistor 1b is formed by forming ohmic electrodes 3b, 4b on both main surfaces of a positive temperature coefficient thermistor body 2b. The positive characteristic thermistor body 2b is
The ceramic body is formed in a substantially circular shape, and the thickness of the ceramic body is formed by notches 9, 10
Except for the above, convex portions 5b and 7b thicker than the central portion are formed.
【００１５】切り欠き９、１０は、正特性サーミスタ素
体２ｂの両主面に図示しないリード線を接続する場合
に、リード線を嵌入させることによって、正特性サーミ
スタ素体２ｂの表面に接続しやすくするためのものであ
る。The notches 9 and 10 are connected to the surface of the positive temperature coefficient thermistor body 2b by inserting the lead wires when connecting lead wires (not shown) to both main surfaces of the positive temperature coefficient thermistor body 2b. This is to make it easier.
【００１６】本発明による第４の実施の形態の正特性サ
ーミスタについて、図５に基づいて説明する。但し、前
述の実施の形態と同様部分については、同様の符号を付
し、詳細な説明を省略する。A positive temperature coefficient thermistor according to a fourth embodiment of the present invention will be described with reference to FIG. However, the same parts as those in the above-described embodiment are denoted by the same reference numerals, and detailed description is omitted.
【００１７】正特性サーミスタ１ｃは、正特性サーミス
タ素体２ｃの両主面にオーミック性の電極３ｃ、４ｃが
形成されたものである。正特性サーミスタ素体２ｃは、
図３に示した正特性サーミスタ素体２ａの両主面の角部
に丸み１１、１２が形成されたものである。つまり、略
矩形状のセラミック体の両主面の対向する周縁部の一部
に、凸状部５ｃ、６ｃ、７ｃ、８ｃが形成されており、
この凸状部５ｃ〜８ｃの角部およびこの凸状部５ｃ〜８
ｃより厚みが薄い両主面の角部に丸み１１、１２が形成
されている。The positive temperature coefficient thermistor 1c is obtained by forming ohmic electrodes 3c, 4c on both main surfaces of a positive temperature coefficient thermistor body 2c. The positive characteristic thermistor body 2c is
The positive characteristic thermistor element body 2a shown in FIG. 3 has roundnesses 11 and 12 formed at the corners of both main surfaces. In other words, convex portions 5c, 6c, 7c, 8c are formed on a part of the opposing peripheral edges of both main surfaces of the substantially rectangular ceramic body,
The corners of the convex portions 5c to 8c and the convex portions 5c to 8c
Roundnesses 11 and 12 are formed at the corners of both main surfaces which are thinner than c.
【００１８】電極３ｃ、４ｃは、正特性サーミスタ素体
２ｃの両主面全面に形成されたＮｉからなる下層電極１
３、１４と、さらにこの下層電極１３、１４の周縁から
ギャップＧを設けて周縁部の下層電極１３、１４が露出
するように形成されたＡｇからなる上層電極１４、１５
の２層から構成されたものである。The lower electrodes 1c made of Ni are formed on the entire surfaces of both main surfaces of the positive temperature coefficient thermistor body 2c.
Upper electrodes 14 and 15 made of Ag formed such that gaps G are provided from the periphery of lower electrodes 13 and 14 to expose lower electrodes 13 and 14 at the periphery.
And two layers.
【００１９】なお、図５に示した上層電極１５、１６
は、凸状部５ｃ〜８ｃを除く中央部に対応する両主面に
形成されたものであるが、この他に図示しないが、ギャ
ップＧがこれより小さく、上層電極１５、１６が凸状部
５ｃ〜８ｃを越えてセラミック素体２ｃの周縁側に近づ
いて形成されてもよい。The upper electrodes 15, 16 shown in FIG.
Are formed on both main surfaces corresponding to the central portion except for the convex portions 5c to 8c. Although not shown, the gap G is smaller than this, and the upper layer electrodes 15 and 16 are It may be formed closer to the peripheral side of the ceramic body 2c beyond 5c to 8c.
【００２０】本発明による第５の実施の形態の正特性サ
ーミスタについて、図６に基づいて説明する。但し、前
述の実施の形態と同様部分については、同様の符号を付
し、詳細な説明を省略する。A positive temperature coefficient thermistor according to a fifth embodiment of the present invention will be described with reference to FIG. However, the same parts as those in the above-described embodiment are denoted by the same reference numerals, and detailed description is omitted.
【００２１】正特性サーミスタ１ｄは、正特性サーミス
タ素体２ｄの両主面にオーミック性の電極３ｄ、４ｄが
形成されたものである。正特性サーミスタ素体２ｄは、
図３に示した正特性サーミスタ素体２ａの周縁部に溝１
７、１８，１９，２０が形成されたものでる。つまり、
正特性サーミスタ素体２ｄは、略矩形状のセラミック体
からなり、セラミック体の厚みが、その両主面の対向す
る周縁部の一部に、中央部に比べて厚い凸状部５ｄ〜８
ｄが形成されており、この凸状部５ｄ〜８ｄの厚み方向
に溝１７〜２０が形成されている。The positive temperature coefficient thermistor 1d is formed by forming ohmic electrodes 3d and 4d on both main surfaces of a positive temperature coefficient thermistor body 2d. The positive characteristic thermistor body 2d is
Grooves 1 are formed on the periphery of the PTC thermistor body 2a shown in FIG.
7, 18, 19, and 20 are formed. That is,
The positive-characteristic thermistor element body 2d is formed of a substantially rectangular ceramic body, and the thickness of the ceramic body is increased at a part of the opposing peripheral portions of both main surfaces thereof, which are thicker than the central portion.
d are formed, and grooves 17 to 20 are formed in the thickness direction of the convex portions 5d to 8d.
【００２２】なお、図３に示した第２の実施の形態の正
特性サーミスタ２ａに基づいて、正特性サーミスタ素体
２ａの周縁部に溝１７〜２０を形成した例を示したが、
これに限定されるものではなく、他の実施の形態の正特
性サーミスタ素体の周縁部に溝を形成したものであって
もよい。Incidentally, an example is shown in which grooves 17 to 20 are formed in the peripheral portion of the positive temperature coefficient thermistor body 2a based on the positive temperature coefficient thermistor 2a of the second embodiment shown in FIG.
The present invention is not limited to this, and a groove may be formed in the peripheral portion of the positive temperature coefficient thermistor body of another embodiment.
【００２３】[0023]
【実施例１】本発明による正特性サーミスタの実施例１
として、図１に示されるように、外径がφ８．２ｍｍ、
両主面間の厚さＴが３．０ｍｍ、凸状部５〜８を含む高
さＨが４．０ｍｍ、凸状部５〜８の幅ｈが１．０ｍｍ、
凸状部５〜８の弧長の中心角αが９０°の略円板状の正
特性サーミスタ素体２を準備し、両主面にＩｎ−Ｇａか
らなる電極３、４を形成して、正特性サーミスタ１を得
た。この正特性サーミスタ１のフラッシュ耐圧を測定し
た結果を表１に記す。なお、実施例１の正特性サーミス
タ１のキュリー温度は１２０℃、常温における抵抗値は
２３Ωであった。Embodiment 1 Embodiment 1 of a PTC thermistor according to the present invention
As shown in FIG. 1, the outer diameter is φ8.2 mm,
The thickness T between the two main surfaces is 3.0 mm, the height H including the convex portions 5 to 8 is 4.0 mm, the width h of the convex portions 5 to 8 is 1.0 mm,
A substantially disc-shaped positive temperature coefficient thermistor element body 2 having a central angle α of 90 ° arc length of the convex portions 5 to 8 is prepared, and electrodes 3 and 4 made of In—Ga are formed on both main surfaces. A positive temperature coefficient thermistor 1 was obtained. Table 1 shows the results of measuring the flash breakdown voltage of the positive temperature coefficient thermistor 1. The Curie temperature of the positive temperature coefficient thermistor 1 of Example 1 was 120 ° C., and the resistance value at room temperature was 23Ω.
【００２４】[0024]
【実施例２】本発明による正特性サーミスタの実施例２
として、図４に示されるように、外径がφ８．２ｍｍ、
両主面間の厚さＴが３．０ｍｍ、凸状部５ｂ、７ｂを含
む高さＨが４．０ｍｍ、凸状部５ｂ、７ｂの幅ｈが１．
０ｍｍ、切り欠き９、１０の幅ｈ１が１．０ｍｍの略円
板状の正特性サーミスタ素体２ｂを準備し、両主面に実
施例１と同様にＩｎ−Ｇａからなる電極３ｂ、４ｂを形
成して、正特性サーミスタ１ｂを得た。この正特性サー
ミスタ１ｂのフラッシュ耐圧を測定した結果を表１に記
す。なお、実施例２の正特性サーミスタ１ｂは、実施例
１と同様にキュリー温度が１２０℃、常温における抵抗
値が２３Ωであった。Embodiment 2 Embodiment 2 of the PTC thermistor according to the present invention
As shown in FIG. 4, the outer diameter is φ8.2 mm,
The thickness T between the two main surfaces is 3.0 mm, the height H including the convex portions 5b and 7b is 4.0 mm, and the width h of the convex portions 5b and 7b is 1.
A substantially disc-shaped positive temperature coefficient thermistor body 2b of 0 mm, notches 9, 10 and a width h1 of 1.0 mm is prepared, and electrodes 3b, 4b made of In-Ga are provided on both main surfaces in the same manner as in Example 1. Thus, a positive temperature coefficient thermistor 1b was obtained. Table 1 shows the results of measuring the flash breakdown voltage of the positive temperature coefficient thermistor 1b. The PTC thermistor 1b of Example 2 had a Curie temperature of 120 ° C. and a resistance value of 23Ω at room temperature, as in Example 1.
【００２５】[0025]
【従来例１】比較のために、従来例１として、図９に示
されるような、外径がφ８．２ｍｍ、両主面の厚さＴが
３ｍｍの円板状の正特性サーミスタ素体３２を準備し、
両主面に実施例１と同様にＩｎ−Ｇａからなる電極３
３、３４を形成して、正特性サーミスタ３１を得た。こ
の正特性サーミスタ３１のフラッシュ耐圧を測定した結
果を表１に記す。Conventional Example 1 For comparison, as a conventional example 1, as shown in FIG. 9, a disk-shaped positive temperature coefficient thermistor body 32 having an outer diameter of φ8.2 mm and a thickness T of both main surfaces of 3 mm. Prepare
Electrodes 3 made of In-Ga on both main surfaces as in Example 1.
By forming Nos. 3 and 34, a positive temperature coefficient thermistor 31 was obtained. Table 1 shows the results of measuring the flash breakdown voltage of the positive temperature coefficient thermistor 31.
【００２６】なお、従来例１の正特性サーミスタ３１
は、実施例１、２の正特性サーミスタ１、１ｂと同様に
キュリー温度が１２０℃、常温における抵抗値が２３Ω
であった。Incidentally, the positive temperature coefficient thermistor 31 of the conventional example 1
Has a Curie temperature of 120.degree. C. and a resistance value of 23 .OMEGA.
Met.
【００２７】[0027]
【表１】 [Table 1]
【００２８】表１を見れば明らかなように、実施例１お
よび実施例２のフラッシュ耐圧は最小値および平均とも
に従来例１のフラッシュ耐圧より大幅に向上した。な
お、フラッシュ耐圧試験において、実施例２の正特性サ
ーミスタ１ｂは、１８個中８個、８１０Ｖで破壊しなか
ったため、８１０Ｖとして平均値を求めた。As apparent from Table 1, the flash withstand voltage of the first and second embodiments was significantly improved both in the minimum value and the average with respect to the flash withstand voltage of the conventional example 1. In the flash withstand voltage test, eight of the 18 positive temperature coefficient thermistors 1b of Example 2 did not break down at 810V, and thus the average value was obtained as 810V.
【００２９】[0029]
【実施例３】実施例３は、実施例１と異なる主原料を用
いて前述の実施例１と同一形状の正特性サーミスタ素体
２を準備し、両主面に実施例１と同一のＩｎ−Ｇａから
なる電極３、４を形成して、正特性サーミスタ１を得
た。実施例３の正特性サーミスタ１のキュリー温度は７
０℃、常温における抵抗値は９Ωであった。Embodiment 3 In the third embodiment, a positive temperature coefficient thermistor body 2 having the same shape as that of the above-mentioned first embodiment is prepared by using a main raw material different from that of the first embodiment, and the same In material as that of the first embodiment is provided on both main surfaces. The electrodes 3 and 4 made of -Ga were formed, and the positive temperature coefficient thermistor 1 was obtained. The Curie temperature of the positive temperature coefficient thermistor 1 of the third embodiment is 7
The resistance at 0 ° C. and normal temperature was 9Ω.
【００３０】実施例３の正特性サーミスタ１についてフ
ラッシュ耐圧及びＰmax を測定した結果を表２に記す。
更に、正特性サーミスタ１の体積を計算によって求めた
結果を表２に記す。Table 2 shows the results of measuring the flash breakdown voltage and Pmax of the PTC thermistor 1 of Example 3.
Further, Table 2 shows the result of calculating the volume of the positive temperature coefficient thermistor 1 by calculation.
【００３１】[0031]
【実施例４】実施例４は、実施例３と同一の主原料を用
いて前述の実施例２と同一形状の正特性サーミスタ素体
２ｂを準備し、両主面に実施例３と同様のＩｎ−Ｇａか
らなる電極３ｂ、４ｂを形成して、正特性サーミスタ１
ｂを得た。実施例４の正特性サーミスタ１ｂは、実施例
３と同じキュリー温度が７０℃、常温における抵抗値が
９Ωであった。Fourth Embodiment In a fourth embodiment, a positive temperature coefficient thermistor body 2b having the same shape as that of the above-described second embodiment is prepared using the same main raw material as that of the third embodiment. The electrodes 3b and 4b made of In-Ga are formed and the PTC thermistor 1 is formed.
b was obtained. The PTC thermistor 1b of Example 4 had the same Curie temperature of 70 ° C. as in Example 3 and a resistance value of 9Ω at room temperature.
【００３２】実施例４の正特性サーミスタ１ｂについて
も、実施例３と同様に、フラッシュ耐圧及びＰmax を測
定した結果、および、正特性サーミスタ１ｂの体積を表
２に記す。As for the positive temperature coefficient thermistor 1b of the fourth embodiment, the results of measuring the flash breakdown voltage and Pmax and the volume of the positive temperature coefficient thermistor 1b are shown in Table 2, as in the third embodiment.
【００３３】[0033]
【従来例２】比較のために、従来例２として、実施例
３、４と同一の主原料を用いて図９に示されるような、
外径がφ８．２ｍｍ、両主面の厚さＴが３ｍｍの円板状
の正特性サーミスタ素体３２を準備し、両主面に実施例
３、４と同様にＩｎ−Ｇａからなる電極３３、３４を形
成して、正特性サーミスタ３１を得た。この従来例２の
正特性サーミスタ３１を実施例３、４と同一の測定を
し、結果を表２に記す。なお、従来例２の正特性サーミ
スタ３１のキュリー温度および常温における抵抗値は、
実施例３、４と同一であった。なお、上述した実施例１
〜４および従来例１、２の測定試料数はそれぞれ１８個
であった。Conventional Example 2 For comparison, as Conventional Example 2, the same main raw materials as in Examples 3 and 4 were used, as shown in FIG.
A disk-shaped positive temperature coefficient thermistor body 32 having an outer diameter of φ8.2 mm and a thickness T of both main surfaces of 3 mm was prepared, and electrodes 33 made of In—Ga were formed on both main surfaces in the same manner as in Examples 3 and 4. , 34 were formed to obtain a positive temperature coefficient thermistor 31. The same measurement as in Examples 3 and 4 was performed on the PTC thermistor 31 of Conventional Example 2 and the results are shown in Table 2. The resistance of the positive temperature coefficient thermistor 31 of Conventional Example 2 at the Curie temperature and the normal temperature is
Same as Examples 3 and 4. Note that the first embodiment described above is used.
The number of measurement samples of each of Nos. 4 to 4 and Conventional Examples 1 and 2 was 18, respectively.
【００３４】ここでＰmax について説明すると、正特性
サーミスタを用いた消磁用回路に電流を流すと、正特性
サーミスタの働きによって消磁コイルに図７に示すよう
な交番減衰電流が流れる。この交番減衰電流の隣り合う
ピーク値の差を包絡線変化量Ｐと呼び、包絡線変化量Ｐ
の最大値をＰmax と呼ぶ。Here, Pmax will be described. When a current is applied to a degaussing circuit using a positive temperature coefficient thermistor, an alternating decay current as shown in FIG. 7 flows through the degaussing coil by the action of the positive temperature coefficient thermistor. The difference between adjacent peak values of the alternating decay current is called an envelope change amount P, and the envelope change amount P
Is referred to as Pmax.
【００３５】Ｐmax の測定条件は、図８に示すように、
消磁コイルの代替として２０Ωの抵抗７３を用い、この
抵抗７３と正特性サーミスタ７４との直列回路にＡＣ２
００Ｖ、６０Ｈｚの電圧７５を印加した。The conditions for measuring Pmax are as shown in FIG.
A 20 Ω resistor 73 is used as a substitute for the degaussing coil, and AC2 is connected to a series circuit of the resistor 73 and the positive temperature coefficient thermistor 74.
A voltage 75 of 00 V, 60 Hz was applied.
【００３６】[0036]
【表２】 [Table 2]
【００３７】表２において、従来例２と比較すれば理解
できるように、正特性サーミスタ素体２、２ｂの主面の
周縁部の一部に凸状部５〜８を設けた実施例３、および
凸状部５ｂ、７ｂを設けた実施例４は、従来例２と比較
してフラッシュ耐圧が大幅に向上すると共に、Ｐmax が
小さくなる。これにより、同じ大きさのフラッシュ耐圧
に耐えるためには、正特性サーミスタ素体の体積を従来
例２より小さくすることが可能となる。なお、フラッシ
ュ耐圧試験において、実施例４の正特性サーミスタ１ｂ
は、１８個中８個、８１０Ｖで破壊しなかったため、８
１０Ｖとして平均値を求めた。In Table 2, as can be understood by comparing with the conventional example 2, the positive characteristic thermistor elements 2, 2b have the convex parts 5 to 8 at a part of the peripheral part of the main surface thereof. In the fourth embodiment provided with the convex portions 5b and 7b, the flash withstand voltage is greatly improved and Pmax is small as compared with the second conventional example. As a result, the volume of the positive temperature coefficient thermistor element can be made smaller than that of the conventional example 2 in order to withstand the flash withstand voltage of the same size. In the flash withstand voltage test, the positive temperature coefficient thermistor 1b of Example 4 was used.
8 of 18 pieces did not break at 810V, so 8
The average value was determined at 10 V.
【００３８】なお、本発明に係る正特性サーミスタは前
記第１〜第５の実施の形態に限定するものでなく、その
要旨の範囲内で種々に変形することができる。例えば、
正特性サーミスタの形状は、外形が略円板状のもの、お
よび略矩形状の平板状のものを示して説明したが、その
他の任意の形状の略平板状のものでもよいことはいうま
でもない。また、正特性サーミスタ素体の周縁部の一部
に形成する凸状部は、一方の主面に形成されていてもよ
く、又凸状部の位置や大きさも任意に選ぶことができ
る。さらにまた、正特性サーミスタ素体に形成される溝
は、一方の主面に形成されているものでもよく、また、
凸状部又は凸状部が形成されていない切り欠きの主面に
形成されていてもよい。The positive temperature coefficient thermistor according to the present invention is not limited to the first to fifth embodiments, but can be variously modified within the scope of the gist. For example,
The shape of the positive temperature coefficient thermistor has been described by referring to a substantially disk-shaped outer shape and a substantially rectangular flat shape, but it is needless to say that the other shape may be a substantially flat shape. Absent. The convex portion formed on a part of the peripheral portion of the positive temperature coefficient thermistor body may be formed on one main surface, and the position and size of the convex portion can be arbitrarily selected. Furthermore, the groove formed in the positive temperature coefficient thermistor body may be formed on one main surface,
It may be formed on the main surface of the convex portion or the notch where the convex portion is not formed.
【００３９】また、下層電極１３、１４の材質について
は、上述したＩｎ−Ｇａ、Ｎｉ等に限定されるものでな
く、Ａｌ、Ｃｒ、Ｃｒ合金又はオーミックＡｇ等オーミ
ック性を有するものであればよい。また、電極の形成方
法についても、スパッタ、印刷、焼き付け、溶射、めっ
き等いずれの方法であってもよい。The material of the lower electrodes 13 and 14 is not limited to In-Ga, Ni or the like described above, but may be any material having ohmic properties such as Al, Cr, Cr alloy or ohmic Ag. . Also, the electrode may be formed by any method such as sputtering, printing, baking, thermal spraying, and plating.
【００４０】さらに、正特性サーミスタ素体の両主面に
形成される電極は、前述した１層からなるもの、および
２層からなるもの以外に、例えば、下層電極にＣｒ、上
層電極として第２層目にモネル、第３層目にＡｇを主成
分とする３層からなる電極から構成されるもの、および
それ以上の複数層からなる電極から構成されてもよい。The electrodes formed on both main surfaces of the positive temperature coefficient thermistor body may be, for example, Cr having a lower electrode and a second electrode having an upper electrode in addition to the above-described one and two layers. The third layer may be composed of Monel, the third layer may be composed of an electrode composed of three layers containing Ag as a main component, or may be composed of an electrode composed of more than two layers.
【００４１】[0041]
【発明の効果】以上述べたように、本発明による正特性
サーミスタは、電極が形成される正特性サーミスタ素体
の主面の周縁部の一部に凸状部を設けてあるために、フ
ラッシュ耐圧が著しく向上する。さらに、比抵抗を下げ
ることなく電極間距離を大きくすることができるため、
電極間によるスパークの発生が減少する。As described above, the positive temperature coefficient thermistor according to the present invention has a flash portion because a convex portion is provided at a part of the peripheral portion of the main surface of the positive temperature coefficient thermistor body on which the electrodes are formed. The withstand voltage is significantly improved. Furthermore, since the distance between the electrodes can be increased without lowering the specific resistance,
The occurrence of sparks between the electrodes is reduced.
【００４２】また、本発明による正特性サーミスタは、
電極が形成される正特性サーミスタ素体の主面の周縁部
近傍に溝を設けてあるために、フラッシュ耐圧が向上す
る。また、本発明による正特性サーミスタは、Ｐmax を
小さくすることなく、小型、軽量にすることができる。
さらに、本発明による正特性サーミスタは、下層電極と
上層電極との間にギャップを設けてあるために、銀マイ
グレーションが防止される。Further, the positive temperature coefficient thermistor according to the present invention is:
Since the groove is provided in the vicinity of the peripheral portion of the main surface of the positive temperature coefficient thermistor body on which the electrode is formed, the flash breakdown voltage is improved. Further, the positive temperature coefficient thermistor according to the present invention can be reduced in size and weight without reducing Pmax.
Further, in the positive temperature coefficient thermistor according to the present invention, since a gap is provided between the lower electrode and the upper electrode, silver migration is prevented.
【図１】本発明に係る第１の実施の形態の正特性サーミ
スタ素体１の斜視図である。FIG. 1 is a perspective view of a PTC thermistor element 1 according to a first embodiment of the present invention.
【図２】図１の正特性サーミスタ１の縦断面図である。FIG. 2 is a longitudinal sectional view of the positive temperature coefficient thermistor 1 of FIG.
【図３】本発明に係る第２の実施の形態の正特性サーミ
スタ１ａの斜視図である。FIG. 3 is a perspective view of a positive temperature coefficient thermistor 1a according to a second embodiment of the present invention.
【図４】本発明に係る第３の実施の形態の正特性サーミ
スタ１ｂの斜視図である。FIG. 4 is a perspective view of a positive temperature coefficient thermistor 1b according to a third embodiment of the present invention.
【図５】本発明に係る第４の実施の形態の正特性サーミ
スタ１ｃの縦断面図である。FIG. 5 is a longitudinal sectional view of a positive temperature coefficient thermistor 1c according to a fourth embodiment of the present invention.
【図６】本発明に係る第５の実施の形態の正特性サーミ
スタ１ｄの縦断面図である。FIG. 6 is a longitudinal sectional view of a positive temperature coefficient thermistor 1d according to a fifth embodiment of the present invention.
【図７】消磁回路の消磁コイルに流れる交番減衰電流を
示す図である。FIG. 7 is a diagram illustrating an alternating decay current flowing through a degaussing coil of the degaussing circuit.
【図８】Ｐmax を測定する回路図である。FIG. 8 is a circuit diagram for measuring Pmax.
【図９】従来の正特性サーミスタの斜視図である。FIG. 9 is a perspective view of a conventional PTC thermistor.
１ 正特性サーミスタ ２ 正特性サーミスタ素体 ３、４ 電極 ５、６、７、８ 凸状部 １１、１２ 丸み １３、１４ 下層電極 １５、１６ 上層電極 １７、１８，１９，２０ 溝 Ｇ ギャップ DESCRIPTION OF SYMBOLS 1 Positive-characteristic thermistor 2 Positive-characteristic thermistor body 3, 4 Electrode 5, 6, 7, 8 Convex part 11, 12 Roundness 13, 14 Lower layer electrode 15, 16 Upper layer electrode 17, 18, 19, 20 Groove G gap
Claims (8)
の厚みがその主面の周縁部の一部が中央部に比べて厚い
サーミスタ素体の両主面に電極が形成されていることを
特徴とする正特性サーミスタ。An electrode is formed on both main surfaces of a thermistor element body having a part whose peripheral part is thicker than a central part of a ceramic body having a positive resistance temperature characteristic. Positive thermistor.
縁部の一部が中央部に比べて凸状であることを特徴とす
る請求項１に記載の正特性サーミスタ。2. The positive temperature coefficient thermistor according to claim 1, wherein a part of peripheral portions of both main surfaces of said positive temperature coefficient thermistor body is convex as compared with a central portion.
が丸みを帯びていることを特徴とする請求項１又は２に
記載の正特性サーミスタ。3. The positive temperature coefficient thermistor according to claim 1, wherein a corner of a peripheral edge of the positive temperature coefficient thermistor body is rounded.
部にこのセラミック体の厚み方向に主面側から溝が形成
されていることを特徴とする請求項１、２又は３に記載
の正特性サーミスタ。4. The ceramic body according to claim 1, wherein a groove is formed in the thickness direction of the ceramic body from a main surface side in a convex portion of a peripheral portion of the positive temperature coefficient thermistor body. Positive thermistor.
り、下層電極が前記正特性サーミスタ素体の両主面全面
に形成されていることを特徴とする請求項１に記載の正
特性サーミスタ。5. The positive temperature coefficient thermistor according to claim 1, wherein said electrode comprises a lower layer electrode and an upper layer electrode, and said lower layer electrode is formed on both main surfaces of said positive temperature coefficient thermistor body.
露出するように前記下層電極より小さな平面積からなる
ことを特徴とする請求項６に記載の正特性サーミスタ。6. The positive temperature coefficient thermistor according to claim 6, wherein said upper layer electrode has a smaller plane area than said lower layer electrode such that the lower layer electrode is exposed at a peripheral portion thereof.
体の凸状の周縁部を除く中央部に対応する両主面に形成
されていることを特徴とする請求項５又は６に記載の正
特性サーミスタ。7. The positive electrode according to claim 5, wherein the upper electrode is formed on both main surfaces corresponding to a central portion of the positive temperature coefficient thermistor body excluding a convex peripheral portion. Characteristic thermistor.
金属からなり、前記上層電極は銀を主成分とする金属か
らなることを特徴とする請求項５、６又は７に記載の正
特性サーミスタ。8. The positive temperature coefficient thermistor according to claim 5, wherein said lower electrode is made of a metal mainly composed of nickel, and said upper electrode is made of a metal mainly composed of silver. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15501397A JP3837838B2 (en) | 1997-06-12 | 1997-06-12 | Positive temperature coefficient thermistor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15501397A JP3837838B2 (en) | 1997-06-12 | 1997-06-12 | Positive temperature coefficient thermistor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH113805A true JPH113805A (en) | 1999-01-06 |
| JP3837838B2 JP3837838B2 (en) | 2006-10-25 |
Family
ID=15596780
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15501397A Expired - Fee Related JP3837838B2 (en) | 1997-06-12 | 1997-06-12 | Positive temperature coefficient thermistor |
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| Country | Link |
|---|---|
| JP (1) | JP3837838B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100697918B1 (en) | 2005-01-12 | 2007-03-20 | 엘에스전선 주식회사 | PTC current limiting device having structure preventing flashover |
-
1997
- 1997-06-12 JP JP15501397A patent/JP3837838B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100697918B1 (en) | 2005-01-12 | 2007-03-20 | 엘에스전선 주식회사 | PTC current limiting device having structure preventing flashover |
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| Publication number | Publication date |
|---|---|
| JP3837838B2 (en) | 2006-10-25 |
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