JPH1062130A - Thin wire detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the detection of the presence or absence of a thin wire stably for a long time by detecting the change of light reception signals at the time when light beam intersects the thin wire with vibrating, etc., a light projecting element and a light receiving element so that the optical axis may pass the thin wire. SOLUTION: A light projecting element 1 such as a LED and a light receiving element 2 such as a photodiode are fixed to a light projecting and receiving element holder 9 in positions facing each other. The holder 9 forms a moving body together with a plate spring 3 to which a permanent magnet 4 is fixed. The permanent magnet 4 forms a magnetic circuit together with an electromagnet 5. Adding an AC current of the frequency of the natural frequency of the moving body to the electromagnet 5 vibrates the moving body, and the optical axis 8 formed of the elements 1 and 2 intersects a thin wire, which is an object to be detected, as vibrating. At this time, the quantity of received light changes. By processing this change by a differentiating circuit to obtain a signal of a preferable S/N ratio, and it is possible to detect the presence or absence of the thin wire. By fixing the light projecting and receiving elements on a substrate to vibrate slits to arrange light beam to intersect the thin wire, a similar effect is obtained.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、光ビームを利用し
被検出物の有無を検出する、いわゆる光電センサーの中
で、特に極細の線状の被検出物を検出するセンサーに関
する。繊維、電線等の産業分野で、特に細い繊維や電線
の非接触検出に広く応用が考えられる。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called photoelectric sensor for detecting the presence or absence of an object using a light beam, and particularly to a sensor for detecting an extremely fine linear object. It can be widely applied to non-contact detection of fine fibers and electric wires in the industrial field of fibers and electric wires.

【０００２】[0002]

【従来の技術】細い線や、小型の物体の有無を非接触で
検出するためには、種々の光電センサーの中でも、小さ
な物体を検出するのに適する、いわゆるファイバーセン
サーを利用するのが一般的である。この場合、被検出体
が光ファイバの有効径に対して小さすぎる場合、言い換
えると光のビームに対して小さすぎる場合には、光源と
して使用されているＬＥＤの温度変化などによる光量変
化の方が、被検出体の有無による光量変化を上廻るた
め、長時間安定して検出することは不可能であった。2. Description of the Related Art In order to detect the presence or absence of a thin line or a small object in a non-contact manner, among various photoelectric sensors, a so-called fiber sensor suitable for detecting a small object is generally used. It is. In this case, if the object to be detected is too small for the effective diameter of the optical fiber, in other words, if it is too small for the light beam, the change in the amount of light due to the temperature change of the LED used as the light source is better. However, since the change in light amount due to the presence or absence of the detection object is exceeded, stable detection for a long time was impossible.

【０００３】そのため、特に細線検出用として、細線の
走行または外部からの振動により細線が微小振動してい
ることを利用し、振動により生ずる受光量の微小変化分
のみを取り出し、光源の光量変化の影響を受けずに、細
線の有無を検出できるように工夫されているものもあ
る。しかし、微少変化分を取り出し、Ｓ／Ｎ比よく増幅
するためには、振動の周波数成分に適合するよう増幅回
路と微分回路を設計する必要がある。振動の周波数は、
細線の材質、長さ、機械振動の周波数成分等により異な
るため、汎用の細線センサーで安定性の良いものの実現
は極めて困難であった。 図３に、従来例の検出部の概
要を示す。[0003] Therefore, in particular, for detecting a fine line, utilizing the fact that the fine line vibrates minutely due to running of the fine line or vibration from the outside, only a minute change in the amount of received light caused by the vibration is extracted, and the change in the light amount of the light source is detected. Some devices are devised so that the presence or absence of a thin line can be detected without being affected. However, in order to extract a minute change and amplify the signal with a good S / N ratio, it is necessary to design an amplifier circuit and a differentiator circuit so as to match the frequency component of the vibration. The frequency of vibration is
Since it differs depending on the material and length of the thin wire, the frequency component of mechanical vibration, and the like, it has been extremely difficult to realize a general-purpose thin wire sensor having good stability. FIG. 3 shows an outline of a conventional detection unit.

【０００４】[0004]

【発明が解決しようとする課題】上記した従来の細線セ
ンサーでは、光量式にあっては細線の有無による光量変
化が極めて小さいため、埃やゴミが受光面に付着した
り、投光光量の温度による変化による受光量変化の方が
大きく、長時間調整することなしに使用することができ
なっかた。In the above-described conventional thin line sensor, in the light amount type, the change in light amount due to the presence or absence of the thin line is extremely small, so that dust or dirt adheres to the light receiving surface, and the temperature of the emitted light amount increases. The change in the amount of received light due to the change caused by the change was larger, and it could not be used without adjusting for a long time.

【０００５】また、細線の振動による受光量の変化分を
検出する方式では、微小な変化分をＳ／Ｎ比よく増幅す
るために、微分回路の時定数を細線の振動周波数に適合
するように設計する必要がある。細線の振動周波数帯域
は線材、太さ、長さ、機械の振動等により決まるもの
で、一種類のセンサで種々の細線の検出を行うことは不
可能であった。各種のセンサを用意し、適切なものを選
択して使用することは、単にセンサのコストが高くなる
のみならず、細線の製造現場において線種が変更された
場合検出が不安定になるなど実用上の問題も大きい。In the method of detecting a change in the amount of received light due to the vibration of the fine wire, the time constant of the differentiating circuit is adjusted to match the vibration frequency of the fine wire in order to amplify the minute change with a good S / N ratio. Need to design. The vibration frequency band of a thin wire is determined by the wire, thickness, length, vibration of a machine, and the like, and it was impossible to detect various thin wires with one type of sensor. Preparing various sensors and selecting the appropriate ones not only increases the cost of the sensor, but also makes the detection unstable when the wire type is changed at the manufacturing site of fine wires. The above problem is also great.

【０００７】本発明は、上記事由に鑑みてなされたもの
で、その目的とするところは、あらゆる細線に対し、長
期間何ら調整などの手段を要せず、安定にその有無を検
出するセンサを提供することにあるThe present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sensor which can stably detect the presence or absence of any thin line without requiring any means such as adjustment for a long period of time. In providing

【０００８】[0008]

【課題を解決するための手段】上記の課題を解決するた
めに、請求項２記載のものは、投光素子と受光素子とを
対向させて投受光ホルダー上に設置し、これらを光軸が
細線を通過するように移動または振動させ、光ビームが
細線を通過するときに生ずる受光信号の変化から細線の
有無を検出する。この場合、光ビームの太さ、移動の速
度により受光信号の変化量の大きさは異なるが、数ミク
ロンの細線でも必要にして十分な変化量を得ることがで
きる。According to a second aspect of the present invention, a light emitting element and a light receiving element are placed on a light emitting and receiving holder so as to face each other. The light beam is moved or vibrated so as to pass through the fine line, and the presence or absence of the fine line is detected from a change in a light receiving signal generated when the light beam passes through the fine line. In this case, the magnitude of the variation of the received light signal varies depending on the thickness of the light beam and the speed of movement, but a necessary and sufficient variation can be obtained even with a fine line of several microns.

【０００９】また、請求項３記載のものは、投受光素子
を移動させず、スリットを移動させる構成にし、請求項
２のものと同様の効果を得ている。Further, according to the third aspect, the slit is moved without moving the light emitting / receiving element, and the same effect as that of the second aspect is obtained.

【００１０】何れの場合も、その検出原理から、細線の
有無による微小な光量変化を光量の絶対値で検出するの
ではなく、光軸が細線を横切るときの瞬時的な光量変化
を微分値により検出するため、埃や投光量の減少などの
漸次的な変動に対し、その影響を受けにくく、長期間、
調整等の手段を要せず安定な動作をさせることができ
る。In any case, based on the detection principle, a minute change in light amount due to the presence or absence of a thin line is not detected by the absolute value of the light amount, but an instantaneous change in the light amount when the optical axis crosses the thin line is calculated by a differential value. For detection, it is less susceptible to gradual fluctuations such as a decrease in dust and the amount of projected light.
A stable operation can be performed without any means such as adjustment.

【００１１】[0011]

【実施例】本発明の第１実施例を図１に基づいて以下に
説明する。１はＬＥＤなどの投光素子で、なるべく拡散
光でなく平行ビームに近い光をだすものが望ましい。投
受光素子間の距離が数ミリメータと短い場合は、通常の
簡単なプラスチックレンズ付きのＬＥＤで充分使用可能
である。２は、ホトダイオードなどの受光素子で、レン
ズ無しのものである。素子自体が０．３ミリメータない
し０．５ミリメータの大きさであれば、細線の径が０．
０１ミリメータ程度までを検出するには、そのまま使用
できるが、素子の寸法が大きいか、細線の径のより細い
ものを検出するときには、適切な幅をもったスリット板
で素子を覆えば良い。９は、これらの投受光素子を対向
して固定するための、投受光素子ホルダーで３の板バネ
とともに移動体を形成する。４は３の板バネに固定され
ている永久磁石で５の電磁石とともに磁気回路を形成す
る。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. Reference numeral 1 denotes a light projecting element such as an LED, which preferably emits light close to a parallel beam rather than diffused light. When the distance between the light emitting and receiving elements is as short as several millimeters, an ordinary LED with a simple plastic lens can be used sufficiently. Reference numeral 2 denotes a light receiving element such as a photodiode without a lens. If the element itself has a size of 0.3 mm to 0.5 mm, the diameter of the fine wire is 0.3 mm.
The device can be used as it is to detect up to about 01 millimeters. However, when detecting a device having a large size or a thin wire, the device may be covered with a slit plate having an appropriate width. Numeral 9 denotes a light emitting and receiving element holder for fixing these light emitting and receiving elements facing each other, and forms a moving body together with the leaf spring 3. Reference numeral 4 denotes a permanent magnet fixed to a leaf spring 3 and forms a magnetic circuit together with an electromagnet 5.

【００１２】５の電磁石に、板バネ３に、投光素子１、
受光素子２、投受光素子ホルダー９および永久磁石４を
固定して構成される移動体の、固有振動数と同じ周波数
の交流電圧を加えると、移動体は共振現象を起こし、図
１において左右に振動を起こす。この振動により、投受
光素子１、２によって形成される光軸８は、細線７を横
切りながら振動する。光軸８が細線を横切るとき、受光
量は変化し、いわゆる微分回路を経て増幅すると、Ｓ／
Ｎ比の良い信号を得ることができる。振動の半周期毎
に、この信号が得られれば、細線の存在が確認でき、細
線が存在しないときには、この信号は現れない。The electromagnet 5, the leaf spring 3, the light emitting element 1,
When an AC voltage having the same frequency as the natural frequency is applied to a moving body constituted by fixing the light receiving element 2, the light emitting and receiving element holder 9 and the permanent magnet 4, the moving body causes a resonance phenomenon, and in FIG. Causes vibration. Due to this vibration, the optical axis 8 formed by the light emitting and receiving elements 1 and 2 vibrates while traversing the thin wire 7. When the optical axis 8 crosses the fine line, the amount of received light changes, and when amplified through a so-called differentiation circuit, S / S
A signal with a good N ratio can be obtained. If this signal is obtained for each half cycle of the vibration, the presence of a thin line can be confirmed, and when there is no thin line, this signal does not appear.

【００１３】次に、第２実施例を図２に基づいて説明す
る。このものは、第１実施例においては、投受光素子が
移動体上にあり、ともに振動していたのに対し、投受光
素子は、基盤上に固定されており、振動するのはスリッ
ト１１、１２が設けられているスリット板１０である。
第１実施例におけるのと同様に、板バネ３に永久磁石
４、スリット板１０を固定して形成される移動体が振動
するとき、両スリットを通過する光ビームが細線を横切
り、第１実施例におけると同様な効果が得られる。ただ
し、光ビームの強度が角度により異なるため、受光信号
は振動周期に同期する波に細線の検出信号が重畳された
形で現れるが、実用上の問題はない。第１実施例に比
べ、利点としては、移動体上から信号線を引き出さなく
ても良いことがあげられる。Next, a second embodiment will be described with reference to FIG. This is because, in the first embodiment, the light emitting / receiving element is on the moving body and vibrates together, whereas the light emitting / receiving element is fixed on the base, and vibrates only in the slit 11, 12 is a slit plate 10 provided with.
As in the first embodiment, when the movable body formed by fixing the permanent magnet 4 and the slit plate 10 to the leaf spring 3 vibrates, the light beam passing through both slits traverses the fine line, The same effect as in the example is obtained. However, since the intensity of the light beam varies depending on the angle, the light reception signal appears in a form in which a thin line detection signal is superimposed on a wave synchronized with the oscillation cycle, but there is no practical problem. As an advantage compared to the first embodiment, there is no need to draw out the signal line from the moving body.

【００１４】[0014]

【発明の効果】請求項２記載のもは、投受光素子ともに
一体となって、移動するため、被検出体が光ビーム内に
無いとき、言い換えれば非検出状態の時の受光レベルは
一定で、検出信号との比，Ｓ／Ｎ比は極めてよく、条件
にもよるが、従来方式の数１０倍から数１００倍改善さ
れており、長期間にわたって安定な検出が可能となっ
た．According to the second aspect of the present invention, since the light emitting and receiving elements move together, the light receiving level is constant when the object to be detected is not in the light beam, in other words, in the non-detection state. The ratio to the detection signal and the S / N ratio were extremely good. Depending on the conditions, the ratio was improved by several tens to several hundreds of the conventional method, and stable detection was possible over a long period of time.

【００１５】請求項２記載のものは、非検出時のレベル
は移動体の振動とともに周期的に変化するが、他は請求
項１のものと同等である。また、本発明の実施例１にお
いて、投受光素子を光ファイバーに置き換え、基盤上に
固定された投受光素子へ光を導く構成でも同様な効果が
得られる。According to the second aspect, the level at the time of non-detection changes periodically with the vibration of the moving body, but the other levels are the same as those of the first aspect. Further, in Embodiment 1 of the present invention, the same effect can be obtained by replacing the light emitting and receiving element with an optical fiber and guiding light to the light emitting and receiving element fixed on the base.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明の第１実施例を示す平面図であるFIG. 1 is a plan view showing a first embodiment of the present invention.

【図２】本発明の第２実施例を示す平面図である。FIG. 2 is a plan view showing a second embodiment of the present invention.

【図３】従来の技術を示す平面図である。FIG. 3 is a plan view showing a conventional technique.

【符号の説明】[Explanation of symbols]

１ 投光素子 ２ 受光素子 ３ 板バネ ４ 永久磁石 ５ 電磁石 ６ 固定ベース ７ 細線（被検出体） ８ 光ビーム ９ 投受光素子ホルダー １０スリット板 １１スリット １２スリット REFERENCE SIGNS LIST 1 light emitting element 2 light receiving element 3 leaf spring 4 permanent magnet 5 electromagnet 6 fixed base 7 fine wire (detected object) 8 light beam 9 light emitting and receiving element holder 10 slit plate 11 slit 12 slit

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】 光ビームを形成し走査する手段と、走査
される光ビームを受光する手段とを有し、走査される光
ビームが、被検出体である細線を直径方向に横切るよう
な構成において、光ビームが細線を横切る時に生ずる受
光信号の変化から、細線を検出することを特徴とする細
線検出器。1. An apparatus comprising: means for forming and scanning a light beam; and means for receiving a light beam to be scanned, wherein the light beam to be scanned traverses a thin line as an object to be detected in a diameter direction. 2. The thin line detector according to claim 1, wherein the thin line is detected from a change in a light receiving signal generated when the light beam crosses the thin line. 【請求項２】 前記において、投光部と受光部とを対向
させて移動体上に固定し、両者の間に、被検出体である
細線を配置し、光ビームが細線を横切るように、移動体
を移動または振動させることを、特徴とする請求項１記
載の細線検出器。2. The method according to claim 1, wherein the light projecting unit and the light receiving unit are fixed to each other on a moving body so as to face each other, a thin line as an object to be detected is arranged between the two, and a light beam crosses the thin line. The thin line detector according to claim 1, wherein the moving body is moved or vibrated. 【請求項３】 請求項１の記載において、投光部と受光
部を対向させて基盤上に固定し、投光部および受光部、
またはどちらか一方の前に移動可能なスリットを設け、
被検出体である細線をスリットにより形成される光ビー
ムが、細線を直径方向に横切るように、スリットを移動
または振動させることを特徴とする細線検出器。3. The light-emitting unit according to claim 1, wherein the light-emitting unit and the light-receiving unit are fixed to each other so as to face each other.
Or provide a movable slit in front of either one,
A thin line detector characterized in that the slit is moved or vibrated so that a light beam formed by a slit on a thin line as an object to be detected crosses the thin line in the diameter direction.