JP4568821B2

JP4568821B2 - Security sensor with interference detection function

Info

Publication number: JP4568821B2
Application number: JP2000052796A
Authority: JP
Inventors: 浩之友岡; 元博渡邊
Original assignee: Optex Co Ltd
Current assignee: Optex Co Ltd
Priority date: 2000-02-29
Filing date: 2000-02-29
Publication date: 2010-10-27
Anticipated expiration: 2020-02-29
Also published as: JP2001243563A

Description

【０００１】
【発明の属する技術分野】
本発明は、受動型赤外線素子を用いた防犯センサについて、シールのような妨害物の貼付を検知する機能を付加する技術に関する。
【０００２】
【従来の技術】
前記防犯センサを用いた侵入者検知システムは、受動型赤外線素子が検知エリア内の人体からの遠赤外線を受けて、人体と周囲温度の差から侵入者を検知するように構成されている。
【０００３】
ところで、妨害行為者が、前記侵入者検知システムの動作を阻害するために人の出入りの多い非警戒動作中に防犯センサが設置されている室内へ侵入し、人体からの遠赤外線が入射する防犯センサのレンズまたはカバーからなる入光側外囲部材の外表面に、遠赤外線を遮断するシールのような妨害物を貼り付けておき、人が出入りしなくなった侵入者検知システムの警戒動作時に室内に侵入する場合がある。
【０００４】
前記のような妨害物の有無を検出する妨害検知装置を備えた防犯センサとして、特開平２−２８７２７８号公報に開示されたものがある。
この妨害検知装置は、投光素子と受光素子とを有し、投光素子から近赤外線または可視光の妨害検知用光線を、人体からの遠赤外線が通過する防犯センサの入光側外囲部材であるレンズの内表面に向けて出射し、受光素子により、前記レンズの内表面からの妨害検知用光線の反射光を受光する。その受光量に基づき、レンズの内表面からの妨害検知用光線の反射光に、レンズの外表面に貼り付けられた妨害物からの妨害検知用光線の反射光が加わることによる、前記受光素子への妨害検知用光線の入射光量の増加を検出することで、レンズの外表面に妨害物があることを検出する。
【０００５】
【発明が解決しようとする課題】
前記妨害検知装置は、レンズの内表面で反射した妨害検知用光線の迷光による前記受光素子への基準入射光量に対して、妨害物からの妨害検知用光線の反射光量が少ない場合、妨害物からの反射光による増加分の検出が難しい。
【０００６】
特に、レンズの外表面に、遠赤外線を遮蔽し、かつ妨害検知用光線である近赤外線から可視光までを透過する透明シールのような妨害物が密着して貼り付けられた場合、妨害物とレンズが一体化した状態となるので、妨害物からの反射光量は極端に少なくなるため、妨害物の検出が更に難しくなり、さらに前記透明シールは目視では識別できないので、妨害物の目視による検出も困難である。
【０００７】
さらに、レンズの着脱が容易な防犯センサでは、レンズが取り外されて、レンズの内表面に、前記透明シールのような妨害物が貼られることが考えられる。この場合、妨害検知用光線の透過光量の変化が少ないため、妨害物の検出が困難になることがあり、さらに妨害物の目視による検出も難しい。
【０００８】
従来、前記透明シールや紙などのような妨害物を検出するために、妨害物を貼り付ける瞬間の妨害検知用光線の変化量（貼り付ける動作そのもの）を捉える方法、または、妨害検知装置の投受光パワーを大きくして検出する方法がとられていた。しかし、前者の方法では常時監視の必要がある上に、誤動作要因により誤検出するおそれがあった。また、後者の方法では小さな虫などが横切るだけで誤検出動作をすることがあった。
【０００９】
本発明は、前記のような問題点を解消するためになされたもので、防犯センサの入光側外囲部材の外表面に前記透明シールのような妨害物が貼り付けられたとき、または入光側外囲部材の内表面に前記透明シールまたは紙のような妨害物が貼り付けられたとき、それらの妨害物の存在を容易に検出できる妨害検知機能付き防犯センサを得ることを目的とする。
【００１０】
前記目的を達成するために、本発明に係る妨害物検知機能付き防犯センサは、赤外線検出素子を有する本体と、この本体に装着されて、前記赤外線検出素子の検知エリアを設定するレンズまたは赤外線検出素子の入射面側を覆うカバーからなる入光側外囲部材と、前記入光側外囲部材の内側から入光側外囲部材へ向けて妨害検知用光線を投光する投光素子と、前記入光側外囲部材に投光された妨害検知用光線の反射光を受光する受光素子と、前記受光素子の受光量に基づいて前記入光側外囲部材の外表面および内表面への妨害物の貼付を検出する検知回路とを備え、前記入光側外囲部材内に入光した妨害検知用光線を、入光側外囲部材の内部で反射させながら、前記受光素子に導くようにしたものである。
【００１１】
上記構成によれば、入光側外囲部材の外表面に透明な妨害物が貼り付けられたときは、入光側外囲部材の外表面と妨害物の内表面との境界面での反射光が加わって入光側外囲部材の内部の反射光量が増すので、受光素子の受光量が増大する。また、入光側外囲部材の内表面に透明シールまたは紙のような妨害物が貼り付けられたときは、入光側外囲部材内に入る妨害検知用光線の光量が減少するので、受光素子の受光量が減少する。ここで、入光側外囲部材自身が反射光を受光素子に導く導光部材を兼ねるから、別途導光部材を設ける必要がない。
【００１２】
また、本発明の好ましい実施形態においては、さらに、入光側外囲部材を透過した妨害検知用光線の一部が入光側外囲部材の外表面に貼り付けられた妨害物で反射された反射光を前記受光素子に導く導光部材を備えている。
上記構成によれば、入光側外囲部材の外表面に貼り付けられた妨害物の、入光側外囲部材の外表面に密着していない部分で反射された妨害検知用光線の反射光が前記導光部材に入射し、この反射光が入光側外囲部材の内部を通って受光素子に入射する反射光に加わるので、受光素子の受光量が増大する。
【００１３】
また、本発明の好ましい実施形態においては、受光素子は入光側外囲部材の端面から出射された前記反射光を受光するものである。
上記構成によれば、受光素子は入光側外囲部材内のいずれの場所からの反射光も、その内部を通って受光できる位置にあるので、妨害検知用光線を入光側外囲部材の広い領域に向けて投光することにより、この広い領域に存在する妨害物からの反射光を受光して、妨害物を検出できる。
【００１４】
【発明の実施の形態】
以下、本発明の実施形態を図面に基づいて説明する。
図１に本発明の第１実施形態に係る防犯センサの斜視図を示す。この防犯センサ１は、天井や壁面に取り付けられるベース２と、このベース２に取り付けられてベース２の前面を覆うケース３とを備えた本体Ａの内部に、受動型遠赤外線検出素子である焦電素子４を収容している。前記ケース３はベース２にねじ止め（図示せず）により開閉可能に固定されている。
【００１５】
図２は、図１のII−II線における防犯センサ１の縦断面図を示す。図２に示すように、ケース３には、入光側外囲部材であるレンズ５が嵌め込まれている。このレンズ５は焦電素子４を保護するカバーを兼ねるもので、遠赤外線を透過するポリエチレンのような合成樹脂で形成されており、その内表面には、焦電素子４の複数の検知エリアＢを設定するフレネルレンズ部６が形成されている。
【００１６】
また、本体Ａの内部でベース２に取り付けられた配線基板１０には、前記焦電素子４と、妨害検知用光線Ｌ１である近赤外線を発生してレンズ５の内側からレンズ５に向かって投光する投光素子１１と、取付台３０を介して受光素子１２とが装着されている。こうして、焦電素子４，投光素子１１および受光素子１２は、ベース２に支持され、ケース３とレンズ５で覆われて、本体Ａの内部に収納されている。投光素子１１は、妨害検知用光線Ｌ１をレンズ５内に入光し易い角度で投光し、受光素子１２は、レンズ５内に入った妨害検知用光線Ｌ１が前記レンズ５の外表面と内表面で反射を繰り返してレンズ内部を通り、レンズ５の中心線Ｃ（図１）と交わる端面５ａから出射する光線を受光する。ここで、レンズ５の前記外表面と内表面はレンズ５とその周囲領域との境界面を指し、妨害検知用光線Ｌ１は、２つの境界面の内側（レンズの内部）で交互に反射して、レンズ５の内部を通る。つまり、レンズ５が光ファイバーのような導光部材として機能する。
【００１７】
前記焦電素子４は、検知エリアＢ内の人体から放出される遠赤外線をレンズ５を介して検出することにより、検知エリアＢ内への人体の侵入を検出する。図３に示した投受光タイミング制御回路１９は、駆動回路１３と受光量検出回路１４に駆動信号を出力し、投光素子１１から妨害検知用光線Ｌ１を投光するタイミングと、受光素子１２の受光量を検出するタイミングとを同期させる。投光素子１１は、駆動回路１３に駆動されて妨害検知用光線Ｌ１をレンズ５の中央の主要部を含む広い領域に向かって投光する。
【００１８】
レンズ５の外表面および内表面に妨害物が貼り付けられていない場合、投光素子１１から投光された妨害検知用光線Ｌ１の一部分はレンズ５を透過して外部に出射され、一部がレンズ５の内表面で反射され、残りがレンズ５の内部でレンズ５の境界面である外表面と内表面の間で反射を繰り返してレンズ５の内部を通り、端面５ａから出射する。受光素子１２はこの端面５ａから出射した妨害検知用光線Ｌ１の反射光を受光する。受光量検出回路１４は、前記投受光タイミング制御回路１９から入力される制御信号に制御されて受光素子１２の受光量に応じた出力電圧Ｖを出力する。妨害物が貼り付けられていないときの基準入射光量に対応する出力電圧Ｖは、図４に示すように、低レベルのほぼ一定値Ｖ０となる。
【００１９】
しかし、レンズ５の外表面に遠赤外線を遮蔽し、近赤外線から可視光線までを透過する透明シールのような妨害物８が貼り付けられた場合は、受光素子１２の受光量が増大し、受光量検出回路１４の出力電圧Ｖは、図４に示すように高レベルのＶ１に増大する。この理由は、図３の妨害物８が無い場合にはレンズ５を透過しようとする妨害検知用光線Ｌ１が、レンズ５の外表面と妨害物８の内表面との境界面で反射されて、その一部が、Ｌ１０で示すように、レンズ５内に戻り、レンズ５の内部で反射を繰り返してレンズ５内を通り、端面５ａから出射するので、受光素子１２での受光量が増大するからである。
【００２０】
また、レンズ５が着脱し易い構造の防犯センサでは、妨害行為者によってレンズ５が取り外されて、レンズ５の内表面に前記透明シールのような妨害物８が貼り付けられる場合がある。この場合は、妨害物８によって妨害検知用光線Ｌ１が反射されて、レンズ５内に入る妨害検知用光線Ｌ１の光量が減るので、受光素子１２の受光量が減少し、受光量検出回路１４の出力電圧Ｖは、図４中に破線で示すように、低レベルのＶ２に減少する。
【００２１】
さらに、図３のレンズ５の内表面に、遠赤外線から可視光線までを吸収して遮蔽する紙のような妨害物８Ｂが貼られる場合がある。この場合は、レンズ５内に入る妨害検知用光線Ｌ１の光量が大きく減るので、受光素子１２の受光量が大幅に減少し、受光量検出回路１４の出力電圧Ｖは、図４中に二点鎖線で示すように、ほぼ零レベルのＶ３となる。
【００２２】
図３の検知回路１５は、第１および第２の比較器１６，１７と警報回路１８とを有しており、第１の比較器１６および第２の比較器１７には前記受光量検出回路１４の出力電圧Ｖが入力され、第１の比較器１６では第１のしきい値ｄ１と比較され、第２の比較器１７では第２のしきい値ｄ２と比較される。前記第１のしきい値ｄ１は、例えば、妨害物が貼り付けられていないときの低レベル電圧Ｖ０の１．１倍程度の値、第２のしきい値ｄ２は、低レベル電圧Ｖ０の０．９倍程度の値に設定されている。
【００２３】
第１の比較器１６は、入力電圧Ｖと第１のしきい値ｄ１とを比較し、Ｖ＞ｄ１となったとき妨害検知信号を警報回路１８に送出し、警報回路１８は、図示していないコントロール室に警報信号を送出する。また、第２の比較器１７は、入力電圧Ｖと第１のしきい値ｄ２とを比較し、Ｖ＜ｄ２となったとき妨害検知信号を警報回路１８に送出し、警報回路１８は、図示していないコントロール室に警報信号を送出する。
【００２４】
このように、レンズ５の外表面に、前記透明シールのような妨害物８が貼り付けられると、受光素子１２の受光量が増大し、レンズ５の内表面に前記透明シールのような妨害物８または前記紙のような妨害物８Ｂが貼り付けられると、受光素子１２の受光量が減少するから、この変化量を検出することで、レンズ５の外表面および内表面に貼られた前記透明シールのような妨害物８や、紙のような妨害物８Ｂを検出することができる。
【００２５】
また、レンズ５自身が反射光を受光素子１２に導く導光部材を兼ねるから、別途導光部材を設ける必要がない。さらに、受光素子１２はレンズ５の端面５ａに対向した位置、つまり、レンズ５上のいずれの場所からの反射光もレンズ５の内部を通って受光できる位置にあるので、妨害検知用光線Ｌ１をレンズ５の広い領域に向けて投光することにより、この広い領域に存在する妨害物８からの反射光を受光して、妨害物８を検出できる。また、レンズ５の外表面に一時的に虫のような小物体が付着しても、これからの反射光量は少ないので、これを妨害物として誤って検出するおそれもない。
【００２６】
図５は本発明の第２実施形態の防犯センサの斜視図、図６は図５のVI−VI線における縦断面図、図７は同実施形態のレンズ内の光の伝播状態と妨害物検出回路の構成を示す概略図である。図５〜７において、図１〜図３と同一符号はそれぞれ同一または相当部分を示している。
図５に示す防犯センサ１は、レンズ５の中心線Ｃと交わる端面５ａ側に、入射面９ａが突出している導光部材９を設けたものである。
【００２７】
図７に示すように、レンズ５の外表面に貼り付けられた妨害物８の端部８ａがレンズ５の外表面に密着しないで外表面から浮き上がっている場合、レンズ５を透過した妨害検知用光線Ｌ１の一部が前記端部８ａで反射され、この反射光の大部分は、Ｌ２０で示すように、レンズ５の外表面で反射されるか、またはレンズ５の外表面の外側近傍を通過し、レンズ５内には戻らない。前記導光部材９は、このような反射光Ｌ２０を受光素子１２に導光するためのものであり、レンズ５のフレネルレンズ部６の領域外に配設され、ケース３に嵌め込まれて装着され、入光側の前部がレンズ５の縁部の外表面上に載っている。
【００２８】
前記導光部材９は、妨害物８の端部８ａで反射された妨害検知用光線Ｌ１の反射光Ｌ２０が入射する入射面９ａと、この入射した妨害検知用光線Ｌ１の反射光Ｌ２０を受光素子１２に向かって反射する反射面９ｂとを備え、妨害物８の浮き上がった端部８ａからの反射光Ｌ２０を導光して、受光素子１２に入射させる。
これにより、受光素子１２の受光量が増大し、受光量検出回路１４の出力電圧Ｖは、図４に示した第１実施形態によって端部が浮き上がった妨害物８を検出する場合の出力電圧よりも高レベルとなる。
【００２９】
なお、レンズ５の内表面に、前記透明シールのような妨害物８および紙のような妨害物８Ｂが貼り付けられたときの受光量検出回路１４の出力電圧Ｖは、第１実施形態のときと同様に減少し、図４のＶ２，Ｖ３のようになる。
【００３０】
図８および図９は、本発明の第３実施形態の防犯センサを示す図で、図８は図９（ａ）のVIII−VIII線における断面図、図９（ａ）は図８のIX−IX線における断面図である。両図において、図１〜図３と同一符号はそれぞれ同一または相当部分を示している。図８に示す防犯センサ１は、その本体Ａが、天井面Ｓに取り付けられるベース２を有し、このベース２に配線基板１０が設けられ、この配線基板１０に装着された支持部材２０，２０に回動調整可能に軸支されている基板２１に、焦電素子４と多面鏡２２を取り付けて、複数の検知エリアＢを形成している。焦電素子４と多面鏡２２に対する遠赤外線の入射面側を覆う不透明な合成樹脂製の半球形のカバー（入光側外囲部材）２４が、ベース２の環状のリップ部２ａの内側に嵌め込まれて取り付けられている。このカバー２４は単にセンサ本体Ａを保護する入光側外囲部材で、検知エリアを設定するレンズ機能は備えていない。
【００３１】
前記カバー２４には、図９（ｂ）に示すように、解放端の一部に切欠部２４ａが形成されており、その底面は図９（ａ）に示すように、カバー内方に向かう傾斜面の端面２４ｂに形成されている。前記切欠部２４ａは、ベース２のリップ部２ａによって覆われて外部に露出しないように設定されている。配線基板１０には、投光素子１１がカバー２４の内表面に近い位置で、かつ投光する妨害検知用光線Ｌ１がカバー２４内に入光し易い角度で支持されており、カバー２４内に侵入した妨害検知用光線Ｌ１が、カバー２４の外表面と内表面の間で反射を繰り返してカバー２４内で前記端面２４ｂに向かって進むように構成されている。
【００３２】
受光素子１２は前記端面２４ｂに対向する姿勢で配線基板１０に装着され、端面２４ｂから出射する妨害検知用光線Ｌ１の反射光を受光するように構成されている。こうして、焦電素子４，投光素子１１および受光素子１２は、本体Ａであるベース２に支持され、カバー２４によって覆われている。投光素子１１には、図３に示した駆動回路１３が接続され、受光素子１２は、受光量検出回路１４および検知回路１５に接続されている。
【００３３】
図９に示すように、この防犯センサ１は、カバー２４の検知エリアＢに対応する面域に、焦電素子４の動作を妨害するために透明シールのような妨害物８が貼り付けられた場合、前記第１実施形態と同様に、妨害物８が無い場合に前記カバー２４内を透過する妨害検知用光線Ｌ１の一部が、妨害物８の内表面で反射されて、Ｌ１０に示すように、カバー２４内に戻り、カバー２４内で反射を繰り返して端面２４ｂから出射するので、この端面２４ａから出射する光量が増大し、前記受光素子１２の受光量が増大する。この結果、図３に示した受光量検出回路１４の出力電圧Ｖが増大し、検知回路１５により、前記第１実施形態と同様に、妨害物８が検出されて警報信号が送出される。
【００３４】
なお、前記各実施形態では、妨害検知用光線Ｌ１として近赤外線を使用したが、レンズ５またはカバー２４が透明である場合、これを透過する可視光線を使用することもできる。
【００３５】
【発明の効果】
以上説明したとおり、本発明の防犯センサは、投光素子から投光されて入光側外囲部材内に入光した妨害検知用光線を、入光側外囲部材の内部で反射させながら、前記受光素子に導くように構成したものであるから、妨害検知用光線を透過する透明シールのような妨害物が入光側外囲部材の外表面に貼り付けられたとき、受光素子の受光量が増大する。また、入光側外囲部材の内表面に、前記透明シールのような妨害物および遠赤外線から妨害検知用光線を遮蔽する紙のような妨害物が貼り付けられたとき、これらの妨害物による反射または遮蔽作用により入光側外囲部材の内部を通って受光素子に受光される反射光の光量が減少する。したがって、この受光量の変化を検知することにより、妨害物を確実に検出することができる。また、入光側外囲部材自身が反射光を受光素子に導く導光部材を兼ねるから、別途導光部材を設ける必要がない。さらに、入光側外囲部材の外表面に一時的に虫のような小物体が付着しても、これからの反射光量は少ないので、これを妨害物として誤って検出するおそれもない。
【図面の簡単な説明】
【図１】本発明の第１実施形態に係る妨害検知機能付き防犯センサの斜視図である。
【図２】図１のII−II線における縦断面図である。
【図３】同実施形態の導光部材内の光の伝播状態と妨害物検出回路の構成を示す概略図である。
【図４】同実施形態の受光量検出回路の出力電圧特性を示す図である。
【図５】本発明の第２実施形態を示す斜視図である。
【図６】図５のVI−VI線における縦断面図である。
【図７】同実施形態のレンズ内の光の伝播状態と妨害物検出回路の構成を示す概略図である。
【図８】本発明の第３実施形態を示す断面図である。
【図９】（ａ）は図８のIX−IX線における断面図、（ｂ）はカバーの斜視図である。
【符号の説明】
１…防犯センサ、２…ベース、３…ケース、４…焦電素子（赤外線検出素子）、５…レンズ（入光側外囲部材）、６…フレネルレンズ部、８，８Ｂ…妨害物、９…導光部材、９ａ…入射面、９ｂ…反射面、１０…配線基板、１１…投光素子、１２…受光素子、１３…駆動回路、１４…受光量検出回路、１５…検知回路、１６…第１比較器、１７…第２比較器、１８…警報回路、２０…支持部材、２１…基板、２２…多面反射鏡、２４…カバー（入光側外囲部材）、２４ａ…切欠部、２４ｂ…端面、Ａ…本体、Ｂ…検知エリア、Ｌ１…妨害検知用光線。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for adding a function of detecting sticking of an obstruction such as a seal to a security sensor using a passive infrared device.
[0002]
[Prior art]
The intruder detection system using the security sensor is configured such that the passive infrared element receives far infrared rays from the human body in the detection area and detects the intruder from the difference between the human body and the ambient temperature.
[0003]
By the way, a crime prevention agent who enters a room where a security sensor is installed during a non-warning operation where many people come and go to block the operation of the intruder detection system, and a far infrared ray from the human body enters. An obstacle such as a seal that blocks far-infrared rays is attached to the outer surface of the light-incident enclosure that consists of the lens or cover of the sensor. May invade.
[0004]
Japanese Patent Laid-Open No. 2-287278 discloses a security sensor provided with a disturbance detection device that detects the presence or absence of an obstruction as described above.
The interference detection device includes a light projecting element and a light receiving element, and a light incident side surrounding member of a security sensor through which a far infrared ray from a human body passes a near-infrared or visible light for interference detection from the light projecting element. The light is emitted toward the inner surface of the lens, and the reflected light of the interference detecting light beam from the inner surface of the lens is received by the light receiving element. Based on the amount of received light, the reflected light of the interference detection light beam from the interference object affixed to the outer surface of the lens is added to the reflected light of the interference detection light beam from the inner surface of the lens. By detecting an increase in the amount of incident light of the interference detection light beam, it is detected that there is an obstruction on the outer surface of the lens.
[0005]
[Problems to be solved by the invention]
The interference detection device is configured so that, when a reflected light amount of the interference detection light beam from the obstacle is small with respect to a reference incident light amount to the light receiving element due to stray light of the interference detection light beam reflected by the inner surface of the lens, the interference detection device It is difficult to detect the increase due to the reflected light.
[0006]
In particular, when an obstacle such as a transparent seal that shields far-infrared rays and transmits from near-infrared rays that are interference detection light rays to visible light is adhered and adhered to the outer surface of the lens, Since the lens is in an integrated state, the amount of light reflected from the obstruction is extremely small, making it more difficult to detect the obstruction. Further, since the transparent seal cannot be visually identified, the obstruction can also be visually detected. Have difficulty.
[0007]
Furthermore, in the security sensor in which the lens can be easily attached and detached, it is conceivable that the lens is removed and an obstruction such as the transparent seal is stuck on the inner surface of the lens. In this case, since there is little change in the transmitted light amount of the interference detection light beam, it may be difficult to detect the interference, and it is also difficult to visually detect the interference.
[0008]
Conventionally, in order to detect an obstruction such as the transparent sticker or paper, a method of capturing the amount of change in the interference detection light beam (the pasting operation itself) at the moment when the obstruction is pasted, A method of detecting by increasing the received light power has been taken. However, the former method requires constant monitoring and may cause erroneous detection due to a malfunction factor. In the latter method, an erroneous detection operation may be performed only by a small insect or the like crossing.
[0009]
The present invention has been made in order to solve the above-described problems. When an obstruction such as the transparent seal is attached to the outer surface of the light incident side surrounding member of the security sensor, It is an object of the present invention to provide a security sensor with an interference detection function capable of easily detecting the presence of an obstruction such as the transparent seal or paper on the inner surface of a light side surrounding member. .
[0010]
In order to achieve the above object, a security sensor with an obstacle detection function according to the present invention includes a main body having an infrared detection element, a lens mounted on the main body and setting a detection area of the infrared detection element, or infrared detection. A light incident side surrounding member composed of a cover covering the incident surface side of the element, and a light projecting element that projects a disturbance detecting light beam from the inside of the light incident side outer member toward the light incident side outer member; A light receiving element that receives the reflected light of the interference detection light beam projected on the light incident side outer member, and an outer surface and an inner surface of the light incident side outer member based on the amount of light received by the light receiving element A detection circuit that detects sticking of an obstruction, and guides the interference detection light beam that has entered the light incident side outer member to the light receiving element while reflecting the light within the light incident side outer member. It is a thing.
[0011]
According to the above configuration, when a transparent obstruction is attached to the outer surface of the incident-side outer enclosure member, reflection at the boundary surface between the outer surface of the incident-side outer enclosure member and the inner surface of the obstruction Since light is added and the amount of reflected light inside the light incident side surrounding member increases, the amount of light received by the light receiving element increases. Also, when an obstruction such as a transparent sticker or paper is attached to the inner surface of the light incident side outer member, the amount of light for detecting interference entering the light incident side outer member is reduced. The amount of light received by the element is reduced. Here, since the light incident side surrounding member itself also serves as a light guide member that guides the reflected light to the light receiving element, it is not necessary to provide a separate light guide member.
[0012]
Further, in a preferred embodiment of the present invention, a part of the interference detection light beam transmitted through the light incident side outer member is reflected by an obstruction attached to the outer surface of the light incident side outer member. A light guide member for guiding reflected light to the light receiving element is provided.
According to the above configuration, the reflected light of the interference detecting light beam reflected by the portion of the obstacle stuck on the outer surface of the light incident side surrounding member that is not in close contact with the outer surface of the light incident side outer member. Is incident on the light guide member, and the reflected light is added to the reflected light incident on the light receiving element through the inside of the light incident side surrounding member, so that the amount of light received by the light receiving element is increased.
[0013]
In a preferred embodiment of the present invention, the light receiving element receives the reflected light emitted from the end surface of the light incident side surrounding member.
According to the above configuration, since the light receiving element is in a position where the reflected light from any place in the light incident side surrounding member can be received through the inside thereof, the interference detection light beam is received by the light incident side outer member. By projecting light toward a wide area, it is possible to receive reflected light from an obstacle present in the wide area and detect the obstacle.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a security sensor according to the first embodiment of the present invention. This security sensor 1 includes a focus 2 which is a passive far-infrared detecting element in a main body A including a base 2 attached to a ceiling or a wall and a case 3 attached to the base 2 and covering the front surface of the base 2. The electric element 4 is accommodated. The case 3 is fixed to the base 2 so as to be openable and closable by screwing (not shown).
[0015]
FIG. 2 is a longitudinal sectional view of the security sensor 1 taken along the line II-II in FIG. As shown in FIG. 2, a lens 5 that is a light incident side surrounding member is fitted in the case 3. The lens 5 also serves as a cover for protecting the pyroelectric element 4 and is formed of a synthetic resin such as polyethylene that transmits far infrared rays. A plurality of detection areas B of the pyroelectric element 4 are formed on the inner surface thereof. A Fresnel lens portion 6 is set.
[0016]
The wiring board 10 attached to the base 2 inside the main body A generates near infrared rays that are the pyroelectric element 4 and the interference detection light beam L1 and projects from the inside of the lens 5 toward the lens 5. A light projecting element 11 that emits light and a light receiving element 12 are mounted via a mounting base 30. Thus, the pyroelectric element 4, the light projecting element 11, and the light receiving element 12 are supported by the base 2, covered with the case 3 and the lens 5, and housed inside the main body A. The light projecting element 11 projects the interference detection light beam L1 at an angle at which it easily enters the lens 5, and the light receiving device 12 transmits the interference detection light beam L 1 entering the lens 5 from the outer surface of the lens 5. The light beam emitted from the end surface 5a intersecting with the center line C (FIG. 1) of the lens 5 is received by repeating reflection on the inner surface. Here, the outer surface and the inner surface of the lens 5 refer to the boundary surface between the lens 5 and the surrounding area, and the interference detection light beam L1 is alternately reflected inside the two boundary surfaces (inside the lens). , Passes through the inside of the lens 5. That is, the lens 5 functions as a light guide member such as an optical fiber.
[0017]
The pyroelectric element 4 detects intrusion of a human body into the detection area B by detecting far infrared rays emitted from the human body in the detection area B through the lens 5. The light projection / reception timing control circuit 19 shown in FIG. 3 outputs a drive signal to the drive circuit 13 and the received light amount detection circuit 14 to project the interference detection light beam L1 from the light projecting element 11, and the light receiving element 12 The timing of detecting the amount of received light is synchronized. The light projecting element 11 is driven by the drive circuit 13 to project the interference detection light beam L <b> 1 toward a wide area including the main part at the center of the lens 5.
[0018]
When no obstruction is attached to the outer surface and the inner surface of the lens 5, a part of the interference detecting light beam L <b> 1 projected from the light projecting element 11 passes through the lens 5 and is emitted to the outside, and a part thereof The light is reflected from the inner surface of the lens 5, and the remainder is reflected between the outer surface and the inner surface which are the boundary surface of the lens 5 inside the lens 5, passes through the inside of the lens 5, and exits from the end surface 5 a. The light receiving element 12 receives the reflected light of the interference detecting light beam L1 emitted from the end face 5a. The received light amount detection circuit 14 is controlled by the control signal input from the light projection / reception timing control circuit 19 and outputs an output voltage V corresponding to the received light amount of the light receiving element 12. As shown in FIG. 4, the output voltage V corresponding to the reference incident light amount when no obstruction is attached is a substantially constant value V0 at a low level.
[0019]
However, when an obstruction 8 such as a transparent seal that shields far-infrared rays from the near-infrared rays to visible rays is attached to the outer surface of the lens 5, the amount of light received by the light-receiving element 12 increases, The output voltage V of the quantity detection circuit 14 increases to a high level V1 as shown in FIG. The reason for this is that when there is no obstruction 8 in FIG. 3, the interference detection light beam L1 that attempts to pass through the lens 5 is reflected by the boundary surface between the outer surface of the lens 5 and the inner surface of the obstruction 8, A part of the light returns to the inside of the lens 5 as indicated by L10, is repeatedly reflected inside the lens 5, passes through the lens 5, and exits from the end face 5a. Therefore, the amount of light received by the light receiving element 12 increases. It is.
[0020]
Further, in a security sensor having a structure in which the lens 5 can be easily attached and detached, there is a case where the lens 5 is removed by an interfering person and the obstruction 8 such as the transparent seal is attached to the inner surface of the lens 5. In this case, the interference detection light beam L1 is reflected by the obstacle 8 and the light amount of the interference detection light beam L1 entering the lens 5 is reduced, so that the light reception amount of the light receiving element 12 is reduced and the light reception amount detection circuit 14 The output voltage V decreases to a low level V2, as indicated by a broken line in FIG.
[0021]
Furthermore, an obstruction 8B such as paper that absorbs and blocks far infrared rays to visible rays may be attached to the inner surface of the lens 5 in FIG. In this case, since the amount of the interference detection light beam L1 entering the lens 5 is greatly reduced, the amount of light received by the light receiving element 12 is greatly reduced, and the output voltage V of the received light amount detection circuit 14 is two points in FIG. As indicated by the chain line, V3 is almost zero level.
[0022]
The detection circuit 15 of FIG. 3 includes first and second comparators 16 and 17 and an alarm circuit 18, and the first comparator 16 and the second comparator 17 include the received light amount detection circuit. The output voltage V of 14 is input, the first comparator 16 compares it with the first threshold value d1, and the second comparator 17 compares it with the second threshold value d2. The first threshold value d1 is, for example, a value about 1.1 times the low level voltage V0 when no obstruction is attached, and the second threshold value d2 is 0 of the low level voltage V0. The value is set to about 9 times.
[0023]
The first comparator 16 compares the input voltage V with the first threshold value d1 and sends a disturbance detection signal to the alarm circuit 18 when V> d1, and the alarm circuit 18 is not shown. Send alarm signal to no control room. The second comparator 17 compares the input voltage V with the first threshold value d2, and sends a disturbance detection signal to the alarm circuit 18 when V <d2, and the alarm circuit 18 Send alarm signal to control room not shown.
[0024]
Thus, when the obstruction 8 such as the transparent seal is attached to the outer surface of the lens 5, the amount of light received by the light receiving element 12 increases, and the obstruction such as the transparent seal is formed on the inner surface of the lens 5. 8 or the obstruction 8B such as paper is pasted, the amount of light received by the light receiving element 12 is reduced. By detecting this amount of change, the transparent pasted on the outer surface and inner surface of the lens 5 is performed. An obstacle 8 such as a seal or an obstacle 8B such as paper can be detected.
[0025]
Further, since the lens 5 itself also serves as a light guide member for guiding the reflected light to the light receiving element 12, it is not necessary to provide a separate light guide member. Furthermore, since the light receiving element 12 is at a position facing the end surface 5a of the lens 5, that is, a position where the reflected light from any location on the lens 5 can be received through the inside of the lens 5, the interference detecting light beam L1 is received. By projecting the light toward the wide area of the lens 5, the reflected light from the obstruction 8 existing in the wide area can be received and the obstruction 8 can be detected. Further, even if a small object such as an insect temporarily attaches to the outer surface of the lens 5, the amount of reflected light is small, so there is no possibility of erroneously detecting this as an obstruction.
[0026]
5 is a perspective view of a security sensor according to a second embodiment of the present invention, FIG. 6 is a longitudinal sectional view taken along line VI-VI in FIG. 5, and FIG. 7 is a light propagation state and obstacle detection in the lens of the same embodiment. It is the schematic which shows the structure of a circuit. 5 to 7, the same reference numerals as those in FIGS. 1 to 3 denote the same or corresponding parts.
The security sensor 1 shown in FIG. 5 is provided with a light guide member 9 with an incident surface 9a protruding on the end surface 5a side that intersects the center line C of the lens 5.
[0027]
As shown in FIG. 7, when the end 8 a of the obstruction 8 affixed to the outer surface of the lens 5 is lifted from the outer surface without being in close contact with the outer surface of the lens 5, for detecting the obstruction that has passed through the lens 5. A part of the light beam L1 is reflected by the end portion 8a, and most of the reflected light is reflected by the outer surface of the lens 5 or passes near the outside of the outer surface of the lens 5, as indicated by L20. However, it does not return into the lens 5. The light guide member 9 is for guiding the reflected light L20 to the light receiving element 12, and is disposed outside the region of the Fresnel lens portion 6 of the lens 5, and is fitted into the case 3 and attached. The front part on the light incident side is placed on the outer surface of the edge part of the lens 5.
[0028]
The light guide member 9 receives an incident surface 9a on which the reflected light L20 of the interference detection light beam L1 reflected by the end 8a of the obstacle 8 is incident, and the reflected light L20 of the incident interference detection light beam L1. A reflection surface 9 b that reflects toward the light 12, and guides the reflected light L <b> 20 from the end portion 8 a where the obstruction 8 is lifted to enter the light receiving element 12.
As a result, the amount of light received by the light receiving element 12 increases, and the output voltage V of the received light amount detection circuit 14 is higher than the output voltage when detecting the obstruction 8 whose end is lifted by the first embodiment shown in FIG. Will also be high.
[0029]
The output voltage V of the received light amount detection circuit 14 when the obstruction 8 such as the transparent seal and the obstruction 8B such as paper are attached to the inner surface of the lens 5 is the same as in the first embodiment. And decrease to V2 and V3 in FIG.
[0030]
8 and 9 are views showing a security sensor according to a third embodiment of the present invention. FIG. 8 is a cross-sectional view taken along the line VIII-VIII in FIG. 9A, and FIG. It is sectional drawing in the IX line. In both figures, the same reference numerals as those in FIGS. 1 to 3 denote the same or corresponding parts. The security sensor 1 shown in FIG. 8 has a main body A having a base 2 attached to a ceiling surface S, a wiring board 10 provided on the base 2, and support members 20, 20 attached to the wiring board 10. A plurality of detection areas B are formed by attaching the pyroelectric element 4 and the polygonal mirror 22 to a substrate 21 that is pivotally supported so as to be rotatable. An opaque synthetic resin-made hemispherical cover (light-incident-side surrounding member) 24 that covers the far-infrared incident surface side of the pyroelectric element 4 and the polygonal mirror 22 is fitted inside the annular lip 2a of the base 2. Attached. The cover 24 is simply a light incident side surrounding member that protects the sensor body A, and does not have a lens function for setting a detection area.
[0031]
As shown in FIG. 9B, the cover 24 is formed with a notch 24a at a part of the open end, and the bottom surface is inclined toward the inside of the cover as shown in FIG. 9A. It is formed on the end face 24b of the surface. The notch 24a is set so as to be covered with the lip 2a of the base 2 and not exposed to the outside. On the wiring board 10, the light projecting element 11 is supported at a position close to the inner surface of the cover 24 and at an angle at which the interference detection light beam L <b> 1 to be projected enters the cover 24 easily. The intrusion detection light beam L1 is configured to repeat reflection between the outer surface and the inner surface of the cover 24 and travel toward the end surface 24b in the cover 24.
[0032]
The light receiving element 12 is mounted on the wiring board 10 so as to face the end face 24b, and is configured to receive the reflected light of the interference detecting light beam L1 emitted from the end face 24b. Thus, the pyroelectric element 4, the light projecting element 11, and the light receiving element 12 are supported by the base 2 that is the main body A and covered with the cover 24. The light projecting element 11 is connected to the drive circuit 13 shown in FIG. 3, and the light receiving element 12 is connected to the received light amount detection circuit 14 and the detection circuit 15.
[0033]
As shown in FIG. 9, the security sensor 1 has an obstruction 8 such as a transparent seal attached to a surface area corresponding to the detection area B of the cover 24 to obstruct the operation of the pyroelectric element 4. In this case, as in the first embodiment, when there is no obstruction 8, a part of the obstruction detection light beam L1 that passes through the cover 24 is reflected by the inner surface of the obstruction 8 and is indicated by L10. In addition, since the light returns into the cover 24 and is repeatedly reflected in the cover 24 and emitted from the end surface 24b, the amount of light emitted from the end surface 24a increases, and the amount of light received by the light receiving element 12 increases. As a result, the output voltage V of the received light amount detection circuit 14 shown in FIG. 3 increases, and the obstacle circuit 8 is detected by the detection circuit 15 as in the first embodiment, and an alarm signal is sent out.
[0034]
In each of the embodiments described above, near infrared rays are used as the interference detection light beam L1, but when the lens 5 or the cover 24 is transparent, visible light that passes through the lens 5 or the cover 24 can also be used.
[0035]
【The invention's effect】
As described above, the security sensor of the present invention reflects the interference detection light beam that has been projected from the light projecting element and entered the light incident side surrounding member, while reflecting the light inside the light incident side outer member, Since it is configured to guide to the light receiving element, the amount of light received by the light receiving element when an obstruction such as a transparent seal that transmits the light for interference detection is attached to the outer surface of the light incident side surrounding member. Will increase. Further, when an obstruction such as the transparent seal and an obstruction such as paper that shields the interference detection light from far infrared rays are attached to the inner surface of the light incident side surrounding member, these obstructions The amount of reflected light received by the light receiving element through the inside of the light incident side surrounding member is reduced by reflection or shielding action. Therefore, by detecting the change in the amount of received light, the obstruction can be reliably detected. Further, since the light incident side surrounding member itself also serves as a light guide member for guiding the reflected light to the light receiving element, it is not necessary to provide a separate light guide member. Further, even if a small object such as an insect temporarily attaches to the outer surface of the light incident side surrounding member, since the amount of reflected light is small, there is no possibility of erroneously detecting this as an obstruction.
[Brief description of the drawings]
FIG. 1 is a perspective view of a security sensor with a disturbance detection function according to a first embodiment of the present invention.
FIG. 2 is a longitudinal sectional view taken along line II-II in FIG.
FIG. 3 is a schematic diagram illustrating a light propagation state in the light guide member and a configuration of an obstruction detection circuit according to the embodiment;
FIG. 4 is a diagram showing output voltage characteristics of the received light amount detection circuit of the same embodiment;
FIG. 5 is a perspective view showing a second embodiment of the present invention.
6 is a longitudinal sectional view taken along line VI-VI in FIG.
FIG. 7 is a schematic diagram illustrating a light propagation state in the lens and a configuration of an obstruction detection circuit in the embodiment.
FIG. 8 is a cross-sectional view showing a third embodiment of the present invention.
9A is a cross-sectional view taken along line IX-IX in FIG. 8, and FIG. 9B is a perspective view of the cover.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Crime prevention sensor, 2 ... Base, 3 ... Case, 4 ... Pyroelectric element (infrared detection element), 5 ... Lens (light incident side surrounding member), 6 ... Fresnel lens part, 8, 8B ... Obstruction, 9 DESCRIPTION OF SYMBOLS ... Light guide member, 9a ... Incident surface, 9b ... Reflection surface, 10 ... Wiring board, 11 ... Light emitting element, 12 ... Light receiving element, 13 ... Drive circuit, 14 ... Light reception amount detection circuit, 15 ... Detection circuit, 16 ... 1st comparator, 17 ... 2nd comparator, 18 ... alarm circuit, 20 ... support member, 21 ... substrate, 22 ... polyhedral reflector, 24 ... cover (light incident side surrounding member), 24a ... notch, 24b ... end face, A ... main body, B ... detection area, L1 ... light for detecting interference.

Claims

A main body having an infrared detection element;
A light incident side surrounding member that is mounted on the main body and includes a lens that sets a detection area of the infrared detection element or a cover that covers an incident surface side of the infrared detection element,
A light projecting element that projects a disturbance detection light beam from the inside of the light incident side outer member toward the light incident side outer member;
A light receiving element that receives reflected light of the interference detection light beam projected on the light incident side surrounding member;
A detection circuit that detects sticking of an obstruction to the outer surface and the inner surface of the light incident side surrounding member based on the amount of light received by the light receiving element;
A security sensor with a tampering detection function for guiding a tampering detection light beam entering the light incident side outer member to the light receiving element while reflecting the light in the light incident side outer member.

2. The light receiving element according to claim 1, further comprising: a reflected light reflected by an obstruction attached to an outer surface of the incident light side surrounding member, a part of the interference detecting light beam transmitted through the incident light side surrounding member. A security sensor with a tampering detection function comprising a light guide member that leads to

3. The security sensor with a disturbance detection function according to claim 1, wherein the light receiving element receives the reflected light emitted from an end surface of the light incident side surrounding member.