JP3640193B2

JP3640193B2 - Planar heating element for mirror

Info

Publication number: JP3640193B2
Application number: JP31886795A
Authority: JP
Inventors: 重範横戸; 浩山口; 光則塚本; 俊一森井; 幸治福田
Original assignee: Tokyo Cosmos Electric Co Ltd
Current assignee: Tokyo Cosmos Electric Co Ltd
Priority date: 1994-12-07
Filing date: 1995-12-07
Publication date: 2005-04-20
Anticipated expiration: 2015-12-07
Also published as: JPH09134777A

Description

【０００１】
【発明の属する技術分野】
この発明は、例えば自動車のミラーや浴室のミラーの裏面に取付けられ、ミラーの曇り取り、霜取りに利用される面状発熱体に関する。
【０００２】
【従来の技術】
自動車のミラーの曇り取りなどのためにミラーの裏面に貼り付けられる従来の面状発熱体は例えば米国特許第４，９３１，６２７号明細書（１９９０年６月５日発行）に示されている。この種の従来の面状発熱体を図８を参照して説明する。取付けられるべきミラーの外形より僅かに小さな外形をもつ、ポリエステルシートのような可撓性の絶縁シート２の裏面に帯状の一対の主電極３、４が、それぞれ絶縁シート裏面の上端縁及び下端縁に沿って、互いに対向して印刷形成される。図８Ａは絶縁シート２が透明であると仮定し、その表面側より透して見た図である。主電極３、４の延長導電路５、６（以下、導電路と称す）がこれら主電極３、４の一端部よりそれぞれ互いに近付くように延長形成され、それらの延長端部は互いに近接対向する端子接続部５ａ、６ａとされている。対向する主電極３、４および導電路５、６よりそれぞれ櫛歯状の副電極７、８が印刷手段により互いに噛み合うように突出形成され、また、図８Ｂに示すように、これら副電極７、８を覆うように電気抵抗体層又は膜９が形成される。
【０００３】
端子接続部５ａ、６ａの位置において絶縁シート２の表面上に一対の端子１１、１２が、それぞれハトメ金具１３によりかしめ付けられて、端子接続部５ａ、６ａにそれぞれ接続される。面状発熱体１には多くの場合、絶縁シート２の抵抗体層９の形成された一面上に両面接着テープ１５が貼り付けられて、ミラー用面状発熱体１が構成される。ミラーに貼り付けるときにその両面接着テープ１５の離型紙１５ａが剥がされてミラーの裏面に貼付けられて使用される。
【０００４】
抵抗体層９は、通常、温度が高くなると抵抗率が高くなる特性をもっているので、ミラー用面状発熱体１に通電した当初は温度が低いため抵抗体層９の抵抗値が小さく、大電流が流れるので、導電路５、６及び主電極３、４のこれら導電路に近い部分は焼損しないように幅が大きく設定される。しかし、主電極３、４はその端末になるほど電流が小さくなるので幅が次第に狭くされている。
【０００５】
【発明が解決しようとする課題】
従来のミラー用面状発熱体１は、主電極３、４が比較的幅広であるため、この主電極３、４の部分では発熱がなされない。つまり、主電極３、４が取付けられた両縁部では発熱がなされない領域が比較的広い。一方、面状発熱体１が取付けられたミラーは周縁からの放熱が大きく、つまり、周縁部の温度が中心部の温度より低い。しかし、この周縁部、特に主電極３、４と対向する部分での発熱がなされないため、ミラーの周縁部の温度が中心部の温度より一層低いものとなっていた。
【０００６】
さらにまた、導電路５、６は幅が広く、比較的大きな面積を占有しており、この部分で発熱が行われないためミラーの導電路５、６と重なる部分の温度が他より低くなる。
このように従来のミラー用面状発熱体の構成では、これが取付けられたミラーの主電極３、４及び導電路５、６と重なる部分での発熱がないから、ミラーの温度分布が一様でなく、前記重なり部分と他の部分とで霜取り等に要する時間のばらつきが大きかった。
【０００７】
この発明の目的は、発熱領域をミラーの周縁にできるだけ近付けると共に、ミラーの全領域に発熱領域を形成し、ミラーの温度分布を均一にして、場所による霜取り等に要する時間のばらつきを抑えることができるミラー用面状発熱体を提供することにある。
【０００８】
【課題を解決するための手段】
この発明の第１の観点によれば、可撓性絶縁シートの主電極、櫛歯状副電極、抵抗体層が形成された側に、可撓性絶縁材よりなる端子装着用基板が接着剤層で貼り合わされ、この端子装着用基板の可撓性絶縁シート側の一面に、帯状の一対の導電路が形成され、これら導電路は、各一端がそれぞれ電極接続手段により対応する主電極の中央部にそれぞれ接続され、上記端子装着用基板の可撓性絶縁シートとは反対側の面の、上記一対の導電路の各他端の位置と対応する位置に、端子が取付けられると共に対応する導電路とそれぞれ接続される。これら端子は電源に接続されるものである。
【０００９】
この発明の第２の観点によれば、主電極、櫛歯状副電極、抵抗体層が形成された可撓性絶縁シートのこれ等が形成された側とは反対側の面の、各主電極の中央部の位置と対応する位置に、端子がそれぞれ取付けられると共に対応する主電極とそれぞれ接続される。これら端子は電源に接続されるものである。
【００１０】
【発明の実施の形態】
この発明の第１の観点による実施例を図１及び図２に、図８と対応する部分には同じ符号を付して示す。この実施例のミラー用面状発熱体１は、可撓性絶縁シート２の主電極３、４、櫛歯状副電極７、８、抵抗体層９が形成される側に、接着剤層２１で貼り合わせれた端子装着用基板２０を有する。
【００１１】
従来と同様に、可撓性絶縁シート２の一面の周辺部に帯状の一対の主電極３、４が対向して形成されている。これら主電極３、４のほぼ中央に、短かい中継電極部３ａ、４ａがそれぞれ互いに内側に突出形成される。これら主電極３、４及び中継電極部３ａ、４ａより櫛歯状の副電極７、８が互いに噛み合うように突出形成され、これら副電極７、８を覆うように、可撓性絶縁シート２の一面に抵抗体層９が形成される。主電極３、４は中継電極部３ａ、４ａから各末端に近づくに従って幅が狭くされている。副電極７、８は可撓性絶縁シート２のほぼ全体にわたり、ほぼ一様に分布されている。抵抗体層（又は抵抗体膜）９は、例えばカーボンとレジンの混合物よりなる電気抵抗体であり、ＰＴＣ（正の温度係数）を有するもの及びＰＴＣを有しないものの何れでもよい。可撓性絶縁シート２の外面に両面接着テープ１５が貼り付けられている。
【００１２】
端子装着用基板２０は、この例では可撓性絶縁シート２と外形をほぼ同じくされ、ポリエステルシートのような可撓性絶縁シートよりなり、図２に図１の一部の拡大断面を示すように、可撓性絶縁シート２側の面上に、帯状の一対の導電路５、６が形成される。これら導電路５、６は、それらの一端部が対応する中継電極部３ａ、４ａと対向しており、かつ電極接続手段でこれら中継電極部３ａ、４ａとそれぞれ接続されている。また、それらの他端部は端子装着用基板２０のコーナー部において互いに接近した状態に形成されており、端子装着用基板２０の可撓性絶縁シート２側とは反対側の面に取付けられた端子１１、１２がこれら導電路５、６の他端部にそれぞれ電気的に接続される。これら端子１１、１２間には図示しない電源から電圧が印加される。
【００１３】
このように上記実施例では導電路５、６が端子装着用基板２０に設けられているため、従来の可撓性絶縁シート２上の導電路が延長形成されていた領域も発熱領域とすることができ、ミラーの温度分布を均一にすることができる。
また、従来においては導電路５、６は主電極３、４のほぼ一端部に接続され、導電路５、６の各電流がほぼ全部の主電極３、４に流れるため主電極３、４の幅の最も広い部分は、導電路の幅とほぼ同一にする必要があった。しかし，主電極３、４の中央に導電路５、６が接続され、導電路５、６にそれぞれ流れる電流のほぼ２分の１が主電極３、４のそれぞれ両側に流れるから、主電極３、４の幅の最も広い部分の幅Ｗは導電路５、６の幅の半分程度でよい。このように主電極３、４の幅が従来より狭くなっただけ、発熱領域をミラーの周縁に近付けることができ、周縁部の温度を上げることができる。
【００１４】
図１に示した実施例では導電路５、６と主電極３、４の電極接続手段としてハトメ金具２３又は鋲を使用し、図２Ｂに示すように、中継電極部３ａ、４ａとこれら中継電極部３ａ、４ａにそれぞれ対向する導電路５、６の一端部との間に、例えば銅よりなる導電ワッシャー（導電スペーサとも言う）２２を介在させておき、この部分で可撓性絶縁シート２及び端子装着用基板２０をハトメ金具２３又は鋲を用いて両外側から挟み固定し、主電極３、４と導電路５、６とを電気的に接続させている。この場合、押え金具２４を端子装着用基板２０の外面に対接させておき、ハトメ金具２３で一緒に固定することにより、固定部を機械的に強くすることもできる。なお、端子１１、１２の取付けと導電路５、６との接続は従来と同様な手法で行われる。
【００１５】
図３は端子装着用基板２０の外面にサーモスタット３１が取付けられたこの発明の第１の観点による他の実施例を示す。一方の導電路５が途中で分離され、その分離された部分間にサーモスタット３１が配され、この導電路５の両分離端とサーモスタット３１の両端とがそれぞれ金具３２、３３で電気的に接続されると共にサーモスタット３１が端子装着用基板２０に取付けられる。ミラー用面状発熱体１の温度がサーモスタット３１のオン／オフによって所定の範囲に押えられる。サーモスタット３１は抵抗体層９が配されている発熱領域と重なるように配されているので、発熱領域の温度に依存して正確にオン／オフされる。もし、サーモスタット３１が従来の図８中の導電路５又は６の途中に挿入配されているような場合には、その位置は発熱領域の温度より低く、また、サーモスタット３１の熱放散によって、一層温度が低下しているので、ミラー用面状発熱体１、従って、ミラーを所定の温度範囲に設定するのが難しくなる。上記実施例では導電路５を途中で分割したが、このような分割をすることなく、導電路５の一端と端子１１との間にサーモスタット３１を電気的に直列に挿入すると共に、サーモスタット３１を端子装着用基板２０の外面に取付けてもよい。
【００１６】
この発明の第２の観点による実施例を図４により説明する。図４において図１〜３及び図８と対応する部分には同一符号を付けてある。この場合には、図１〜３中から端子装着用基板２０が削除され、可撓性絶縁シート２上の中継電極部３ａ、４ａにそれぞれ端子１１、１２が電気的に接続される。即ち、これら中継電極部３ａ、４ａと対向する、可撓性接続シート２の中継電極部３ａ、４ａとは反対側の面において、端子１１、１２がハトメ金具又は鋲１３により取付けられると共に中継電極部３ａ、４ａと電気的に接続される。図５に示すように可撓性絶縁シート２の左右の周辺に主電極３、４を形成させてもよい。このように主電極３、４を左右に形成することは、図４に示した実施例を適用する場合に限らず、図１、図３に示した実施例にも適用できる。
【００１７】
この発明の第２の観点による他の実施例を、図６及び図７に、図１、図２、図４と対応する部分に同一符号を付けて示す。この実施例では図４の絶縁シート２の抵抗体層９形成面と反対の面に、図１に示したと同様の導電路５、６が形成され、導電路５、６の各端部は中継電極部３ａ、４ａと対向する位置とされ、電極部３ａと導電路５の一端部とがハトメ金具又は鋲４１でその互いに外側がかしめつけられると共に電気的に互いに接続され、同様に電極部４ａと導電路６の一端部とがハトメ金具、又は鋲４２で互いに固定されると共に電気的に接続される。これら接続部を補強するために、導電ワッシャー４３、４４をそれぞれハトメ金具又は鋲４１、４２により同時にかしめつけるとよい。
【００１８】
導電路５、６の他端部は絶縁シート２の一端部に位置すると共に互いに接近され、導電路５、６のこの他端部と電気的に接続されて端子１１、１２がそれぞれハトメ金具又は鋲１３により絶縁シート２に固定される。端子１１、１２は電源に接続されるものである。
導電路５、６を外部環境に対し保護するため、これら導電路５、６が形成された絶縁シート２の一面側に、ただし端子１１、１２が取り付けられた部分を除いて、絶縁層、例えば両面接着テープ４５が貼り付けられる。この場合、端子１１、１２が取り付けられた絶縁シート２の一面側の部分に対応する両面接着テープ４５の部分は絶縁シート２の一面側に貼り付ける前に切除しておき、この切除部分を有する両面接着テープ４５を絶縁シート２の一面側に貼り付けることが好ましい。通常、両面接着テープ４５の外表面の離型紙４５ａは剥がさない。
【００１９】
さらに、端子１１、１２が取り付けられた絶縁シート２の一面側の露出された部分にシリコンゴム接着剤などの絶縁層４６が形成されて外部環境に対して端子１１、１２装着部分を保護している。シリコンゴム接着剤は乾燥するまでにかなりの時間がかかるから、初めに、切除部分を有する両面接着テープ４５を導電路５、６が形成された絶縁シート２の一面側に貼り付け、次いで端子１１、１２が取り付けられた絶縁シート２の一面側の露出された部分にシリコンゴム接着剤４６を被着することが好ましい。他の適当な電気絶縁性接着剤が端子１１、１２を被覆するために使用できることは言うまでもない。
【００２０】
例示の実施例では、電気絶縁層として両面接着テープ４５を使用し、端子１１、１２が取り付けられた部分を除いて、導電路５、６が形成された絶縁シート２の一面側の全面に両面接着テープ４５を貼り付けた。勿論、両面接着テープ以外の他の電気絶縁物質が、端子１１、１２が取り付けられた部分を除く絶縁シート２の一面側の全面を、或いは導電路５、６の表面部分及び、必要ならばそれらの周囲部分のみを被覆するために、使用できる。
【００２１】
しかしながら、両面接着テープを使用すると、端子１１、１２が取り付けられた絶縁シート２の一面側の部分に対応する両面接着テープ４５の部分を予め切除しておくことにより、端子１１、１２が取り付けられた部分を除いて、導電路５、６が形成された絶縁シート２の一面側の全面に両面接着テープ４５を非常に容易に貼り付けることができ、その結果、作業性が著しく向上し、他の絶縁材料を使用する場合と比較して、作業時間が大幅に短縮できるという顕著な利点がある。さらに、端子１１、１２が取り付けられた絶縁シート２の一面側の露出された部分は非常に小さな面積であるから、単に少量のシリコンゴム接着剤４６を絶縁シート２の一面側の露出された各部分に塗布するだけで十分であり、従って、シリコンゴム接着剤４６の塗布作業が容易になり、その作業性が向上する。
【００２２】
なお、絶縁シート２の抵抗体層９の形成された外表面上に両面接着テープ１５が貼り付けられている。前述したように、この両面接着テープ１５はその外表面に、この装置をミラーに貼り付ける前に剥がされる離型紙１５ａを具備する。
【００２３】
【発明の効果】
この発明の第１の観点によれば、導電路５、６が絶縁シート２から端子装着用基板２０に移され、その結果、可撓性絶縁シート２のほぼ全面に発熱領域が形成されるから、ミラーの温度分布のばらつきを小さくすることができる。また、主電極の中央に導電路が接続され、主電極の幅を狭くすることができるから、放熱の激しいミラーの周縁部に発熱領域を近付けることができる。
【００２４】
さらに、この発明の第２の観点によれば、端子装着用基板が削除され、電源に接続されるべき端子が主電極に直接的に接続されるから、第１の観点による場合と同じ有益な効果がもたらされ、しかも安価に製造することができる。
【図面の簡単な説明】
【図１】この発明の第１の観点の実施例を示し、Ａは平面図、Ｂは端子装着用基板２０を外した状態の平面図、Ｃは正面図である。
【図２】Ａは図１Ａ中の I−I 線拡大断面図、Ｂは図１Ａ中のII−II線拡大断面図である。
【図３】この発明の第１の観点の他の実施例を示し、Ａは平面図、Ｂは端子装着用基板２０を外した状態の平面図、Ｃは正面図である。
【図４】この発明の第２の観点の実施例を示し、Ａは平面図、Ｂは絶縁シート２の底面図、ＣはＡ中の III−III 線拡大断面図である。
【図５】この発明の第２の観点の他の実施例を示し、Ａは平面図、Ｂは絶縁シート２の底面図、Ｃは正面図である。
【図６】この発明の第２の観点のさらに他の実施例を示し、Ａは両面接着テープ１５、４５を剥がした平面図、Ｂはその底面図、Ｃは正面図である。
【図７】Ａは図６Ａ中のIV−IV線拡大断面図、Ｂは図６Ａ中の V−V 線拡大断面図である。
【図８】従来のミラー用面状発熱体の一例を示し、Ａは平面図、ＢはＡ中のIV−IV線拡大断面図、Ｃは電気的回路図である。
【符号の説明】
１：ミラー用面状発熱体
２：絶縁シート
３、４：主電極
３ａ、４ａ：中継電極部
５、６：導電路
７、８：副電極
９：抵抗体層
１１、１２：端子
１３、２３：ハトメ金具又は鋲
１５、４５：両面接着テープ
２０：端子装着用基板
２１：接着剤層
２２：導電ワッシャー
２４：押え金具
３１：サーモスタット
４１、４２：ハトメ金具又は鋲
４３、４４：導電ワッシャー
４６：絶縁層（シリコンゴム接着剤）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a planar heating element that is attached to, for example, a rear surface of a mirror of a car or a mirror of a bathroom and is used for defrosting and defrosting the mirror.
[0002]
[Prior art]
A conventional sheet heating element attached to the back surface of a mirror for defrosting an automobile mirror is disclosed, for example, in US Pat. No. 4,931,627 (issued on June 5, 1990). . This type of conventional planar heating element will be described with reference to FIG. A pair of strip-like main electrodes 3 and 4 on the back surface of a flexible insulating sheet 2 such as a polyester sheet having an outer shape slightly smaller than the outer shape of the mirror to be mounted are respectively an upper edge and a lower edge on the back surface of the insulating sheet. Are printed opposite to each other. FIG. 8A is a view seen through from the surface side assuming that the insulating sheet 2 is transparent. Extended conductive paths 5 and 6 (hereinafter referred to as conductive paths) of the main electrodes 3 and 4 are formed so as to approach each other from one end portions of the main electrodes 3 and 4, and these extended end portions are close to and opposed to each other. Terminal connection portions 5a and 6a are provided. Comb-like sub-electrodes 7 and 8 project from the opposing main electrodes 3 and 4 and the conductive paths 5 and 6 so as to mesh with each other by the printing means, and as shown in FIG. An electric resistor layer or film 9 is formed so as to cover 8.
[0003]
A pair of terminals 11 and 12 are caulked by eyelet fittings 13 on the surface of the insulating sheet 2 at the positions of the terminal connection portions 5a and 6a, respectively, and connected to the terminal connection portions 5a and 6a, respectively. In many cases, the sheet heating element 1 is configured by attaching a double-sided adhesive tape 15 on one surface of the insulating sheet 2 on which the resistor layer 9 is formed, thereby forming the mirror sheet heating element 1. When being attached to the mirror, the release paper 15a of the double-sided adhesive tape 15 is peeled off and attached to the back surface of the mirror.
[0004]
The resistor layer 9 usually has a characteristic that the resistivity increases as the temperature rises. Therefore, since the temperature is initially low when the mirror sheet heating element 1 is energized, the resistance value of the resistor layer 9 is small and a large current is applied. Therefore, the widths of the conductive paths 5 and 6 and the main electrodes 3 and 4 near the conductive paths are set large so as not to burn out. However, since the currents of the main electrodes 3 and 4 become smaller toward the terminals, the width is gradually narrowed.
[0005]
[Problems to be solved by the invention]
In the conventional planar heating element 1 for mirrors, the main electrodes 3 and 4 are relatively wide, so that the main electrodes 3 and 4 do not generate heat. That is, a region where heat is not generated is relatively wide at both edges where the main electrodes 3 and 4 are attached. On the other hand, the mirror to which the planar heating element 1 is attached has a large heat dissipation from the periphery, that is, the temperature at the periphery is lower than the temperature at the center. However, since heat is not generated in the peripheral portion, particularly the portion facing the main electrodes 3 and 4, the temperature of the peripheral portion of the mirror is much lower than the temperature of the central portion.
[0006]
Furthermore, the conductive paths 5 and 6 have a wide width and occupy a relatively large area. Since heat is not generated in this portion, the temperature of the portion overlapping the conductive paths 5 and 6 of the mirror is lower than the others.
As described above, in the configuration of the conventional planar heating element for mirrors, since there is no heat generation in the portion overlapping the main electrodes 3 and 4 and the conductive paths 5 and 6 of the mirror to which the mirror is mounted, the temperature distribution of the mirror is uniform. In addition, there was a large variation in time required for defrosting between the overlapping portion and other portions.
[0007]
The object of the present invention is to make the heat generation area as close as possible to the periphery of the mirror and to form the heat generation area in the entire area of the mirror so as to make the temperature distribution of the mirror uniform, thereby suppressing variations in time required for defrosting depending on the location. An object of the present invention is to provide a planar heating element for mirrors.
[0008]
[Means for Solving the Problems]
According to the first aspect of the present invention, a terminal mounting substrate made of a flexible insulating material is an adhesive on the side of the flexible insulating sheet on which the main electrode, the comb-like subelectrode, and the resistor layer are formed. A pair of strip-shaped conductive paths are formed on one surface of the terminal mounting substrate on the side of the flexible insulating sheet, and each of the conductive paths is connected to the center of the main electrode corresponding to each end by the electrode connecting means. The terminals are attached to the terminals on the opposite side of the terminal mounting substrate from the flexible insulating sheet, corresponding to the positions of the other ends of the pair of conductive paths. Each is connected to the road. These terminals are connected to a power source.
[0009]
According to the second aspect of the present invention, each of the main electrodes, the comb-shaped sub-electrodes, the flexible insulating sheet on which the resistor layer is formed, each main surface on the side opposite to the side on which these are formed. Terminals are respectively attached to the positions corresponding to the positions of the central portions of the electrodes and connected to the corresponding main electrodes. These terminals are connected to a power source.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment according to the first aspect of the present invention is shown in FIGS. 1 and 2 with portions corresponding to those in FIG. The planar heating element 1 for a mirror according to this embodiment has an adhesive layer 21 on the side of the flexible insulating sheet 2 on which the main electrodes 3 and 4, the comb-like sub-electrodes 7 and 8 and the resistor layer 9 are formed. The terminal mounting substrate 20 is bonded together.
[0011]
As in the prior art, a pair of strip-like main electrodes 3 and 4 are formed on the periphery of one surface of the flexible insulating sheet 2 so as to face each other. Short relay electrode portions 3a and 4a are formed so as to protrude inward from each other at approximately the center of the main electrodes 3 and 4, respectively. Comb-like sub-electrodes 7 and 8 protrude from the main electrodes 3 and 4 and the relay electrode portions 3a and 4a so as to mesh with each other, and the flexible insulating sheet 2 is covered so as to cover the sub-electrodes 7 and 8. A resistor layer 9 is formed on one surface. The widths of the main electrodes 3 and 4 are narrowed as they approach each end from the relay electrode portions 3a and 4a. The sub-electrodes 7 and 8 are distributed substantially uniformly over almost the entire flexible insulating sheet 2. The resistor layer (or resistor film) 9 is an electric resistor made of, for example, a mixture of carbon and resin, and may be any of those having PTC (positive temperature coefficient) and those not having PTC. A double-sided adhesive tape 15 is affixed to the outer surface of the flexible insulating sheet 2.
[0012]
In this example, the terminal mounting substrate 20 has substantially the same outer shape as the flexible insulating sheet 2 and is made of a flexible insulating sheet such as a polyester sheet. FIG. 2 shows a partially enlarged cross section of FIG. In addition, a pair of strip-like conductive paths 5 and 6 are formed on the surface of the flexible insulating sheet 2 side. The conductive paths 5 and 6 are opposed to the corresponding relay electrode portions 3a and 4a at one end portions thereof, and are connected to the relay electrode portions 3a and 4a by electrode connecting means, respectively. Further, the other end portions thereof are formed in a state of being close to each other at the corner portion of the terminal mounting substrate 20 and are attached to the surface of the terminal mounting substrate 20 opposite to the flexible insulating sheet 2 side. Terminals 11 and 12 are electrically connected to the other end portions of the conductive paths 5 and 6, respectively. A voltage is applied between these terminals 11 and 12 from a power source (not shown).
[0013]
As described above, since the conductive paths 5 and 6 are provided in the terminal mounting substrate 20 in the above-described embodiment, the region where the conductive path on the conventional flexible insulating sheet 2 is formed to be extended is also a heat generating region. The temperature distribution of the mirror can be made uniform.
Conventionally, the conductive paths 5 and 6 are connected to almost one end of the main electrodes 3 and 4, and each current of the conductive paths 5 and 6 flows to almost all the main electrodes 3 and 4. The widest part needs to be almost the same as the width of the conductive path. However, since the conductive paths 5 and 6 are connected to the center of the main electrodes 3 and 4, and approximately half of the current flowing through the conductive paths 5 and 6 flows to both sides of the main electrodes 3 and 4, respectively. The width W of the widest portion of 4 may be about half the width of the conductive paths 5 and 6. As described above, since the widths of the main electrodes 3 and 4 are narrower than those in the prior art, the heat generation region can be brought closer to the periphery of the mirror, and the temperature of the periphery can be raised.
[0014]
In the embodiment shown in FIG. 1, eyelet fittings 23 or scissors are used as electrode connection means for the conductive paths 5 and 6 and the main electrodes 3 and 4, and as shown in FIG. 2B, the relay electrode portions 3 a and 4 a and these relay electrodes are used. A conductive washer (also referred to as a conductive spacer) 22 made of, for example, copper is interposed between the ends of the conductive paths 5 and 6 that face the portions 3a and 4a, respectively. The terminal mounting substrate 20 is sandwiched and fixed from both outsides using eyelet fittings 23 or scissors, and the main electrodes 3 and 4 and the conductive paths 5 and 6 are electrically connected. In this case, the fixing portion 24 can be mechanically strengthened by bringing the presser fitting 24 into contact with the outer surface of the terminal mounting substrate 20 and fixing it together with the eyelet fitting 23. In addition, attachment of the terminals 11 and 12 and connection with the conductive paths 5 and 6 are performed by a method similar to the conventional method.
[0015]
FIG. 3 shows another embodiment according to the first aspect of the present invention in which a thermostat 31 is attached to the outer surface of the terminal mounting board 20. One conductive path 5 is separated in the middle, and a thermostat 31 is arranged between the separated parts, and both separated ends of the conductive path 5 and both ends of the thermostat 31 are electrically connected by metal fittings 32 and 33, respectively. The thermostat 31 is attached to the terminal mounting board 20. The temperature of the planar heating element 1 for the mirror is kept within a predetermined range by turning on / off the thermostat 31. Since the thermostat 31 is arranged so as to overlap with the heat generating region in which the resistor layer 9 is provided, it is turned on / off accurately depending on the temperature of the heat generating region. If the thermostat 31 is inserted and arranged in the middle of the conductive path 5 or 6 in FIG. 8, the position is lower than the temperature of the heat generating region, and further, due to heat dissipation of the thermostat 31. Since the temperature is lowered, it becomes difficult to set the planar heating element 1 for a mirror, and thus the mirror, within a predetermined temperature range. In the above embodiment, the conductive path 5 is divided in the middle, but without such division, the thermostat 31 is electrically inserted in series between one end of the conductive path 5 and the terminal 11, and the thermostat 31 is You may attach to the outer surface of the board | substrate 20 for terminal mounting.
[0016]
An embodiment according to the second aspect of the present invention will be described with reference to FIG. 4, parts corresponding to those in FIGS. 1 to 3 and FIG. In this case, the terminal mounting substrate 20 is deleted from FIGS. 1 to 3, and the terminals 11 and 12 are electrically connected to the relay electrode portions 3 a and 4 a on the flexible insulating sheet 2, respectively. That is, the terminals 11 and 12 are attached by eyelet fittings or ridges 13 on the surface opposite to the relay electrode portions 3a and 4a of the flexible connection sheet 2 facing the relay electrode portions 3a and 4a, and the relay electrode. It is electrically connected to the parts 3a, 4a. As shown in FIG. 5, the main electrodes 3 and 4 may be formed around the left and right sides of the flexible insulating sheet 2. Forming the main electrodes 3 and 4 on the left and right in this way is not limited to the case where the embodiment shown in FIG. 4 is applied, but can also be applied to the embodiment shown in FIGS.
[0017]
Another embodiment according to the second aspect of the present invention is shown in FIGS. 6 and 7 by assigning the same reference numerals to the portions corresponding to those in FIGS. In this embodiment, conductive paths 5 and 6 similar to those shown in FIG. 1 are formed on the surface of the insulating sheet 2 of FIG. 4 opposite to the surface on which the resistor layer 9 is formed, and each end of the conductive paths 5 and 6 is relayed. The electrode portions 3a and 4a are opposed to each other, and the electrode portion 3a and one end portion of the conductive path 5 are caulked on the outside by a eyelet fitting or a hook 41 and are electrically connected to each other. Similarly, the electrode portion 4a And one end of the conductive path 6 are fixed to each other by an eyelet fitting or a hook 42 and electrically connected. In order to reinforce these connecting portions, the conductive washers 43 and 44 are preferably caulked simultaneously by eyelet fittings or hooks 41 and 42, respectively.
[0018]
The other ends of the conductive paths 5 and 6 are located at one end of the insulating sheet 2 and are close to each other, and are electrically connected to the other ends of the conductive paths 5 and 6 so that the terminals 11 and 12 respectively It is fixed to the insulating sheet 2 by the flange 13. Terminals 11 and 12 are connected to a power source.
In order to protect the conductive paths 5 and 6 from the external environment, an insulating layer, for example, except for a portion where the terminals 11 and 12 are attached to one side of the insulating sheet 2 where the conductive paths 5 and 6 are formed. Double-sided adhesive tape 45 is affixed. In this case, the part of the double-sided adhesive tape 45 corresponding to the part on the one surface side of the insulating sheet 2 to which the terminals 11 and 12 are attached is excised before being attached to the one surface side of the insulating sheet 2 and has this excised part. It is preferable to affix the double-sided adhesive tape 45 to one side of the insulating sheet 2. Usually, the release paper 45a on the outer surface of the double-sided adhesive tape 45 is not peeled off.
[0019]
Furthermore, an insulating layer 46 such as a silicone rubber adhesive is formed on the exposed portion of the one surface side of the insulating sheet 2 to which the terminals 11 and 12 are attached to protect the mounting portions of the terminals 11 and 12 against the external environment. Yes. Since the silicone rubber adhesive takes a considerable amount of time to dry, first, a double-sided adhesive tape 45 having a cut portion is attached to one side of the insulating sheet 2 on which the conductive paths 5 and 6 are formed, and then the terminal 11 , 12 is preferably attached to the exposed portion of one surface side of the insulating sheet 2 with a silicon rubber adhesive 46. Of course, other suitable electrically insulating adhesives can be used to coat the terminals 11, 12.
[0020]
In the illustrated embodiment, a double-sided adhesive tape 45 is used as an electrical insulating layer, and both sides of the insulating sheet 2 on which the conductive paths 5 and 6 are formed are formed on both sides except for the portion where the terminals 11 and 12 are attached. Adhesive tape 45 was affixed. Of course, other electrical insulating materials other than the double-sided adhesive tape may cover the entire surface of one side of the insulating sheet 2 excluding the portion to which the terminals 11 and 12 are attached, or the surface portions of the conductive paths 5 and 6 and, if necessary, those. Can be used to coat only the surrounding area of
[0021]
However, when the double-sided adhesive tape is used, the terminals 11 and 12 are attached by cutting in advance a portion of the double-sided adhesive tape 45 corresponding to a portion on one side of the insulating sheet 2 to which the terminals 11 and 12 are attached. The double-sided adhesive tape 45 can be very easily affixed to the entire surface of the one side of the insulating sheet 2 on which the conductive paths 5 and 6 are formed except for the above-mentioned parts. Compared with the case of using this insulating material, there is a significant advantage that the working time can be greatly shortened. Furthermore, since the exposed portion of the one surface side of the insulating sheet 2 to which the terminals 11 and 12 are attached has a very small area, a small amount of silicon rubber adhesive 46 is simply applied to each exposed surface of the insulating sheet 2. It is sufficient to apply to the portion. Therefore, the operation of applying the silicon rubber adhesive 46 is facilitated, and the workability is improved.
[0022]
In addition, the double-sided adhesive tape 15 is affixed on the outer surface where the resistor layer 9 of the insulating sheet 2 is formed. As described above, the double-sided adhesive tape 15 has a release paper 15a on its outer surface, which is peeled off before the device is attached to the mirror.
[0023]
【The invention's effect】
According to the first aspect of the present invention, the conductive paths 5 and 6 are transferred from the insulating sheet 2 to the terminal mounting substrate 20, and as a result, a heat generating region is formed on almost the entire surface of the flexible insulating sheet 2. The variation in the temperature distribution of the mirror can be reduced. In addition, since the conductive path is connected to the center of the main electrode and the width of the main electrode can be narrowed, the heat generation region can be brought close to the peripheral portion of the mirror that is radiating heat.
[0024]
Furthermore, according to the second aspect of the present invention, since the terminal mounting substrate is deleted and the terminal to be connected to the power source is directly connected to the main electrode, it is the same beneficial as in the case of the first aspect. It is effective and can be manufactured at low cost.
[Brief description of the drawings]
FIG. 1 shows an embodiment of the first aspect of the present invention, in which A is a plan view, B is a plan view with a terminal mounting board 20 removed, and C is a front view.
2A is an enlarged sectional view taken along line II in FIG. 1A, and B is an enlarged sectional view taken along line II-II in FIG. 1A.
3A and 3B show another embodiment of the first aspect of the present invention, in which A is a plan view, B is a plan view with a terminal mounting board 20 removed, and C is a front view.
4 shows an embodiment of the second aspect of the present invention, in which A is a plan view, B is a bottom view of the insulating sheet 2, and C is an enlarged sectional view taken along line III-III in A. FIG.
FIG. 5 shows another embodiment of the second aspect of the present invention, in which A is a plan view, B is a bottom view of the insulating sheet 2, and C is a front view.
FIG. 6 shows still another embodiment of the second aspect of the present invention, in which A is a plan view with the double-sided adhesive tapes 15 and 45 removed, B is a bottom view thereof, and C is a front view.
7A is an enlarged sectional view taken along line IV-IV in FIG. 6A, and B is an enlarged sectional view taken along line VV in FIG. 6A.
FIG. 8 shows an example of a conventional sheet heating element for a mirror, in which A is a plan view, B is an enlarged sectional view taken along line IV-IV in A, and C is an electrical circuit diagram.
[Explanation of symbols]
1: Mirror sheet heating element 2: Insulating sheet 3, 4: Main electrode 3a, 4a: Relay electrode portion 5, 6: Conductive path 7, 8: Sub electrode 9: Resistor layer 11, 12: Terminals 13, 23 : Eyelet bracket or scissors 15, 45: Double-sided adhesive tape 20: Terminal mounting substrate 21: Adhesive layer 22: Conductive washer 24: Presser bracket 31: Thermostat 41, 42: Eyelet bracket or scissors 43, 44: Conductive washer 46: Insulating layer (silicon rubber adhesive)

Claims

A flexible insulating sheet;
First and second main electrodes respectively formed along a pair of opposing edges on one surface of the insulating sheet;
One end of each of the first main electrode and the second main electrode is connected to each other, and a plurality of first sub-electrodes and a plurality of second sub-electrodes respectively formed on the one surface of the insulating sheet in a comb-like shape meshing with each other. A sub-electrode;
A resistor layer that covers the first and second sub-electrodes and is formed on the one surface of the insulating sheet;
A terminal mounting substrate made of a flexible insulating sheet in which the resistor layer above Symbol insulating sheet is attached on the side to be formed,
A first conductive path formed on a surface on the insulating sheet side of the terminal-mounting substrate facing the resistor body and the one end portion of the first main electrode and the second main electrode facing each other; A second conductive path;
First and second electrode connecting means for electrically connecting the one end of the first and second conductive paths and the first and second main electrodes, respectively;
First and second terminals that are attached to the outer surface of the terminal mounting substrate at the other end portions of the first and second conductive paths, and are electrically connected to the first and second conductive paths, respectively. ,
A planar heating element for mirrors, comprising:

2. The planar heating element for a mirror according to claim 1, wherein the first and second conductive paths are connected to the first and second main electrodes at the central portions of the first and second main electrodes, respectively.

The first and second electrode connecting means include
First and second relay electrode portions respectively formed on the one surface of the insulating sheet and connected to the first and second main electrodes;
Conductive washer means inserted between the first and second relay electrode portions and the one end of the first and second conductive paths, respectively.
The insulating sheet and the terminal mounting substrate are pressed from the outside of the insulating sheet and the terminal mounting substrate, and the first and second relay electrode portions and the one end portions of the first and second conductive paths are First and second eyelet fittings for pressure-fixing to the conductive washer;
The planar heating element for mirrors according to claim 2, comprising:

4. The planar heating element for a mirror according to claim 2, wherein the other end portions of the first and second conductive paths are in an opposed state close to each other.

A thermostat is electrically connected in series between one end of one of the first and second conductive paths and one of the first and second terminals connected to the one conductive path, and the thermostat is The planar heating element for a mirror according to claim 4, which is attached to a terminal mounting substrate and positioned on the resistor layer.

6. The mirror surface according to claim 5, wherein the one conductive path is cut into two conductive path portions on the way, and adjacent ends of the cut conductive path portions are electrically connected by the thermostat. Heating element.

The planar heating element for a mirror according to claim 6, wherein a double-sided adhesive tape is attached to the opposite side of the surface of the insulating sheet on which the resistor layer is formed.