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)
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JP15501397A JP3837838B2 (en) | 1997-06-12 | 1997-06-12 | Positive temperature coefficient thermistor |
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JP15501397A JP3837838B2 (en) | 1997-06-12 | 1997-06-12 | Positive temperature coefficient thermistor |
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JPH113805A true JPH113805A (en) | 1999-01-06 |
JP3837838B2 JP3837838B2 (en) | 2006-10-25 |
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KR100697918B1 (en) | 2005-01-12 | 2007-03-20 | 엘에스전선 주식회사 | PTC current limiting device having structure preventing flashover |
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1997
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Cited By (1)
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