JPH0287023A - Liquid level detection sensor - Google Patents
Liquid level detection sensorInfo
- Publication number
- JPH0287023A JPH0287023A JP24041388A JP24041388A JPH0287023A JP H0287023 A JPH0287023 A JP H0287023A JP 24041388 A JP24041388 A JP 24041388A JP 24041388 A JP24041388 A JP 24041388A JP H0287023 A JPH0287023 A JP H0287023A
- Authority
- JP
- Japan
- Prior art keywords
- light
- liquid
- detected
- reflecting surface
- liquid level
- 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.)
- Pending
Links
- 239000007788 liquid Substances 0.000 title claims abstract description 44
- 238000001514 detection method Methods 0.000 title claims abstract description 13
- 229920000515 polycarbonate Polymers 0.000 abstract description 8
- 239000004417 polycarbonate Substances 0.000 abstract description 8
- 239000000463 material Substances 0.000 abstract description 5
- 239000011521 glass Substances 0.000 abstract description 2
- 239000011347 resin Substances 0.000 abstract description 2
- 229920005989 resin Polymers 0.000 abstract description 2
- 230000035945 sensitivity Effects 0.000 abstract description 2
- 238000000034 method Methods 0.000 description 9
- 230000003287 optical effect Effects 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 230000000694 effects Effects 0.000 description 4
- 230000031700 light absorption Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
Landscapes
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は容器内に収納する液体の量を液面のレベルによ
って検知する液面レベル検知センサに関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid level detection sensor that detects the amount of liquid contained in a container based on the liquid level.
従来の液面レベル検知センサとしては容器を構成する面
の一部の機械的振動特性の変化を検知する方法、被検知
液体に浮くフロートの位置を検知する方法、発光素子の
光を被検知液体を通して受光素子で検出する光学的方法
等が知られている。Conventional liquid level detection sensors include a method that detects changes in the mechanical vibration characteristics of a part of the surface of a container, a method that detects the position of a float floating on the liquid to be detected, and a method that detects the position of a float floating on the liquid to be detected. Optical methods are known in which light is detected using a light-receiving element.
［発明が解決しようとする課題］
上記方法のうち振動特性の変化を検出する方法では高周
波加振を行うためまた振動を検出するための回路が複雑
になり、フロートを用いる方法では十分な浮力を得るた
めに大きなフロートを必要とする等の問題がある。−月
光学的方法では周辺の回路構成が簡単な小型のセンサが
構成できるというメリットを有する。しかしながら被検
知液体の光吸収特性を利用するため該液体の吸光特性が
必要であり、十分な光吸収を生ずるためには十分な量の
液体を発光素子と受光素子の間に介在させなければなら
ず透明な液体には適用できないという問題点を有してい
た。[Problems to be Solved by the Invention] Among the above methods, the method of detecting changes in vibration characteristics involves high-frequency excitation and the circuit for detecting vibration is complicated, and the method of using a float requires sufficient buoyancy. There are problems such as the need for a large float to obtain this value. - The lunar optical method has the advantage that a small sensor with a simple peripheral circuit configuration can be constructed. However, in order to utilize the light absorption properties of the liquid to be detected, the light absorption properties of the liquid are required, and in order to cause sufficient light absorption, a sufficient amount of liquid must be interposed between the light emitting element and the light receiving element. However, it has the problem that it cannot be applied to transparent liquids.
本発明の目的はこれらの問題点を解決して透明液体を含
むあらゆる液体に適用でき少量の液体でも検知てきる簡
単な構造の小型の液面レベル検知センサを提供すること
にある。SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a small liquid level detection sensor with a simple structure that can be applied to all liquids including transparent liquids and can detect even small amounts of liquid.
本発明の液面レベル検知センサは少なくとも一面の反射
面を有する光案内部材、発光部材、受光部材とを有し、
上記反射面が被検知液体に接触しない状態で全反射を生
じ、上記反射面が被検知液体に接触している状態では全
反射を生じない角度で、
上記発光部材から射出する光の少なくとも一部が上記反
射面に入射するごとく構成したことを特徴とする。The liquid level detection sensor of the present invention includes a light guiding member, a light emitting member, and a light receiving member each having at least one reflective surface, and causes total reflection in a state where the reflective surface does not contact the liquid to be detected, and the reflective surface The light emitting member is characterized in that it is configured such that at least a portion of the light emitted from the light emitting member is incident on the reflecting surface at an angle that does not cause total reflection when the light emitting member is in contact with the liquid to be detected.
本発明の上記構成では反射面に接する被検知液体の有無
により生ずる全反射臨界角の変化を利用して生ずる光量
変化によって液面レベルを検出する。In the above-mentioned configuration of the present invention, the liquid level is detected by the change in the amount of light produced by utilizing the change in the critical angle of total reflection caused by the presence or absence of the liquid to be detected in contact with the reflective surface.
次に実施例に基づいて本発明を説明する。第１図は本発
明の一実施例を示す液面レベル検知センサの断面図を示
す。本センサは光案内部材３の一面を反射面４とし反射
面に向けて発光素子２の光を照射しこの光の反射光を受
光素子１て検出する構成になっている。Next, the present invention will be explained based on examples. FIG. 1 shows a sectional view of a liquid level detection sensor showing an embodiment of the present invention. This sensor has a configuration in which one surface of the light guide member 3 is a reflective surface 4, and light from a light emitting element 2 is irradiated toward the reflective surface, and the light receiving element 1 detects the reflected light of this light.
光案内部材３の材質としては光の透過率が高いこと（透
明性が良好なこと）が望ましくガラスや、ポリカーボネ
ート、ポリエステル、アクリル等の樹脂材料を用いるこ
とができる。本実施例ではポリカーボネートを用いてい
る。発光素子、受光素子は外乱に強く十分な光量および
感度が得られることから赤外光発光の発光ダイオード、
ホトトランジスタを用いている。The material of the light guide member 3 preferably has high light transmittance (good transparency), and may be glass, or a resin material such as polycarbonate, polyester, or acrylic. In this embodiment, polycarbonate is used. Light-emitting elements and light-receiving elements are resistant to external disturbances and provide sufficient light intensity and sensitivity, so infrared light-emitting light-emitting diodes,
It uses a phototransistor.
上記構成において被検出液体が水の場合について動作を
説明する。ポリカーボネート、空気、水の屈折率はそれ
ぞれ１．５８，１．０，１．３３である。従って全反射
は屈折率の高い部材から低い部材へ光が射出する場合に
起こり、それぞれの場合の全反射の生ずる入射角（臨界
角）は水、ポリカーボネート間 ５５．４度空気、ポ
リカーボネート間 ３９．２度である。また本実施例
の発光素子では射出角度の範囲の十分狭い指向性の高い
素子を得ることができる。この時発光素子の光の入射角
が４７度であるように発光素子の光軸および光案内部材
の入射面を設定する。次に受光素子の光軸は発光素子の
光軸と反射面の交点（第１図中５で示す）を通りかつ出
射角４７度（図中７で示す）に設定し配置する。The operation will be described in the case where the liquid to be detected is water in the above configuration. The refractive indices of polycarbonate, air, and water are 1.58, 1.0, and 1.33, respectively. Therefore, total internal reflection occurs when light exits from a member with a high refractive index to a member with a low refractive index, and the angle of incidence (critical angle) at which total internal reflection occurs in each case is between water and polycarbonate: 55.4 degrees between air and polycarbonate 39. Twice. Further, in the light emitting element of this example, a highly directional element with a sufficiently narrow range of emission angles can be obtained. At this time, the optical axis of the light emitting element and the incident surface of the light guide member are set so that the incident angle of light from the light emitting element is 47 degrees. Next, the optical axis of the light-receiving element is set to pass through the intersection of the optical axis of the light-emitting element and the reflecting surface (indicated by 5 in FIG. 1), and the emission angle is set to 47 degrees (indicated by 7 in the figure).
本センサを被検知液体を収納する容器の一部に反射面を
実質上鉛直方向に向けて第２図に示すように液漏れ防止
用ブツシュ２１を介して取付ける。This sensor is attached to a part of a container containing a liquid to be detected, with its reflective surface facing substantially vertically, via a liquid leakage prevention bushing 21, as shown in FIG.
この時反射面に液体が達していない場合ポリカーボネー
トと空気の間の臨界角より大きい入射角で光が入射する
ため全反射し受光素子に達する。この様子は第１図に斜
線を付した光路として示す。At this time, if the liquid has not reached the reflective surface, the light will be incident at an incident angle greater than the critical angle between the polycarbonate and air, and will be totally reflected and reach the light receiving element. This situation is shown in FIG. 1 as a hatched optical path.
（ただし簡単のために発光は点発光、受光は両受光とし
て図示する。）次に液面が上昇し反射面の交点５を覆う
レベルに達すると入射角が水、ポリカーボネート間の臨
界角より小さいため全反射が生じないため光は受光素子
に達しない。（この時の光路を第１図中に破線で示す。(However, for simplicity, the light emission is shown as point light emission, and the light reception is shown as double light reception.) Next, when the liquid level rises and reaches a level that covers the intersection 5 of the reflective surface, the incident angle is smaller than the critical angle between water and polycarbonate. Therefore, total reflection does not occur and the light does not reach the light receiving element. (The optical path at this time is shown by a broken line in FIG. 1.
）従って反射面に接する水の有無に応じて受光素子で検
出する光量の小太が生ずるため液面の検知を行うことが
できる。) Therefore, the amount of light detected by the light receiving element varies depending on the presence or absence of water in contact with the reflective surface, making it possible to detect the liquid level.
別の実施例を第３図に示す。第２図と同じ光案内部材、
発光素子、受光素子を用い間隙３３を介して光吸収部材
３１を設は構成される。光吸収部材は水が反射面に接す
る場合に透過する光を黒色の光吸収面３２で吸収する。Another embodiment is shown in FIG. The same light guide member as in Fig. 2,
A light absorbing member 31 is constructed using a light emitting element and a light receiving element through a gap 33. The light absorbing member absorbs the light transmitted when water comes into contact with the reflective surface with the black light absorbing surface 32.
透過光の吸収が被検知液体によらず生ずるため極く少量
の液体でもまた光吸収の小さい液体でも光量変化が大き
くとれ正確に検知できるというメリットを有する。さら
に吸収部材を検知センサと一体化せず容器の一部として
第１の実施例と同じセンサ構造として構成することもで
きる。Since the absorption of transmitted light occurs regardless of the liquid to be detected, it has the advantage that even a very small amount of liquid or a liquid with low light absorption can have a large change in the amount of light and can be accurately detected. Furthermore, the absorbing member may not be integrated with the detection sensor but may be configured as a part of the container to have the same sensor structure as the first embodiment.
なお上記入射角の設定は関係する材質の屈折特性、発光
素子特性に応じて上記値に限定されることなく設定でき
る。Note that the above-mentioned incident angle can be set without being limited to the above-mentioned value depending on the refraction characteristics of the materials involved and the characteristics of the light emitting element.
以上述べたように本発明の上記構成によれば反射面に生
ずる臨界角変化を検出する方式であるため反射面界面近
傍に存在する透明及び各色の液体を含む極く少量の液体
で検知ができるという効果を有する。検出出力が電位レ
ベル信号として直接得られるため信号処理等必要としな
いという効果も有する。さらに小型で簡単な構成のセン
サーが構成できるという効果も有する。As described above, according to the above configuration of the present invention, since the method detects the critical angle change that occurs on the reflective surface, it is possible to detect a very small amount of liquid, including transparent and liquids of various colors, existing near the reflective surface interface. It has this effect. Since the detection output is directly obtained as a potential level signal, there is also the advantage that no signal processing is required. Furthermore, it has the effect that a sensor with a small size and simple configuration can be constructed.
第１図は本発明による一実施例を示す液面レベル検知セ
ンサの構成を示す図。
第２図は本発明の一実施例を示す液面レベル検知センサ
の取付は状態を示す図。
第３図は本発明の別の実施例を示す液面レベル検知セン
サの構成を示す図。
１ 受光素子
２ 発光素子
３ 光案内部材
４ 反射面
３１ 光吸収部材
以上
出願人 セイコーエプソン株式会社
代理人 弁理士 鈴木喜三部 他１名
１支を１子
２売先東チ
３ 先鳴き内部オ第
４反！Ｎ面
第１図FIG. 1 is a diagram showing the configuration of a liquid level detection sensor showing an embodiment according to the present invention. FIG. 2 is a diagram illustrating the installation state of a liquid level detection sensor according to an embodiment of the present invention. FIG. 3 is a diagram showing the configuration of a liquid level detection sensor showing another embodiment of the present invention. 1 Light-receiving element 2 Light-emitting element 3 Light guide member 4 Reflective surface 31 Light-absorbing member Applicant Seiko Epson Co., Ltd. agent Patent attorney Kizobe Suzuki and 1 other person 1 branch 1 child 2 Seller destination East China 3 Priority internal office 4th anti! N side figure 1
Claims (1)
、受光部材とを有し、 上記反射面が被検知液体に接触しない状態で全反射を生
じ、上記反射面が被検知液体に接触している状態では全
反射を生じない角度で、 上記発光部材から射出する光の少なくとも一部が上記反
射面に入射するごとく構成したことを特徴とする液面レ
ベル検知センサ。[Scope of Claims] A light guiding member, a light emitting member, and a light receiving member each having at least one reflective surface, wherein total reflection occurs in a state where the reflective surface does not contact the liquid to be detected, and the reflective surface has at least one reflective surface to be detected. A liquid level detection sensor characterized in that the sensor is configured such that at least a portion of the light emitted from the light emitting member is incident on the reflective surface at an angle that does not cause total reflection when in contact with the liquid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24041388A JPH0287023A (en) | 1988-09-26 | 1988-09-26 | Liquid level detection sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24041388A JPH0287023A (en) | 1988-09-26 | 1988-09-26 | Liquid level detection sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0287023A true JPH0287023A (en) | 1990-03-27 |
Family
ID=17059103
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24041388A Pending JPH0287023A (en) | 1988-09-26 | 1988-09-26 | Liquid level detection sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0287023A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009112331A (en) * | 2007-11-01 | 2009-05-28 | Mitsubishi Electric Corp | Steam recovering device and cooker with steam recovering device |
| KR100977515B1 (en) * | 2007-06-26 | 2010-08-23 | 한국 고덴시 주식회사 | Optical liquid level sensor |
| JP2012093232A (en) * | 2010-10-27 | 2012-05-17 | Nippon Aleph Corp | Photosensor and level sensor |
-
1988
- 1988-09-26 JP JP24041388A patent/JPH0287023A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100977515B1 (en) * | 2007-06-26 | 2010-08-23 | 한국 고덴시 주식회사 | Optical liquid level sensor |
| JP2009112331A (en) * | 2007-11-01 | 2009-05-28 | Mitsubishi Electric Corp | Steam recovering device and cooker with steam recovering device |
| JP2012093232A (en) * | 2010-10-27 | 2012-05-17 | Nippon Aleph Corp | Photosensor and level sensor |
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