JPH02168142A - Humidity sensor - Google Patents
Humidity sensorInfo
- Publication number
- JPH02168142A JPH02168142A JP32461188A JP32461188A JPH02168142A JP H02168142 A JPH02168142 A JP H02168142A JP 32461188 A JP32461188 A JP 32461188A JP 32461188 A JP32461188 A JP 32461188A JP H02168142 A JPH02168142 A JP H02168142A
- Authority
- JP
- Japan
- Prior art keywords
- laser beam
- cell
- wavelength
- humidity
- laser
- 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
- 230000003287 optical effect Effects 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 13
- 238000001514 detection method Methods 0.000 abstract description 5
- 238000005259 measurement Methods 0.000 abstract 1
- 238000010521 absorption reaction Methods 0.000 description 4
- 229910052736 halogen Inorganic materials 0.000 description 3
- 150000002367 halogens Chemical class 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 235000019687 Lamb Nutrition 0.000 description 1
- 238000000862 absorption spectrum Methods 0.000 description 1
- 230000005466 cherenkov radiation Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 230000031700 light absorption Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000000813 microbial effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
Landscapes
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
Description
【発明の詳細な説明】
（伺産業上の利用分野
本発明はレーザ光を用いた湿度センサに関する乙のであ
る。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Use) The present invention relates to a humidity sensor using laser light.
（ロ）従来の技術
ＵＣ来の湿度検知は例えば近赤外領域のうちある特定の
波長光は水に吸収されるという原理を用いていた。すな
わち、近赤外領域における水の吸収波長１．４３．１．
９４μｍのうちのひとつを主波長とし、さらに外乱によ
る影響を補正するために水に吸収されない波長光を比較
光として用い１両者のエネルギー托から湿度を求める方
法が用いられＣいた。しかしながら、赤外光源として用
いられるハロゲンランプは安定性に乏しく、精度を上げ
るためにはハロゲンランプの温度を上昇させ、赤外光の
放射エイ・ルギーを増大させねばならない。このため、
寿命が短かく、消費電力も大きくなるという欠点があっ
た。また、水の吸収スペクトルのうち、Ｍｔｔｌ吸収の
大きい波長は２７μｍであり、ハロゲンランプの場合、
この波長の放射エネルギーは小さいため、最適な波長を
使えないという欠点もあった。(b) Conventional technology Humidity detection in UC has used the principle that, for example, light of a certain wavelength in the near-infrared region is absorbed by water. That is, the absorption wavelength of water in the near-infrared region is 1.43.1.
A method was used in which one of the wavelengths of 94 μm was used as the dominant wavelength, and in order to correct the influence of disturbances, a wavelength light that was not absorbed by water was used as comparison light, and the humidity was determined from the energy ratio of both. However, the halogen lamp used as the infrared light source has poor stability, and in order to improve the accuracy, the temperature of the halogen lamp must be increased to increase the radiation energy of the infrared light. For this reason,
The disadvantages are that it has a short lifespan and consumes a lot of power. Also, in the absorption spectrum of water, the wavelength with large Mttl absorption is 27 μm, and in the case of a halogen lamp,
Since the radiant energy of this wavelength is small, there was also the drawback that the optimum wavelength could not be used.
（ハ）発明が解決しようとする課題
本発明はこのような点に鑑みて為されたものであって、
検出精度が高く経時的に安定性のある湿度センサを実現
しようとするものである。(c) Problems to be solved by the invention The present invention has been made in view of the above points.
The aim is to realize a humidity sensor with high detection accuracy and stability over time.
（勾課題を解決するための手段
本発明では、一定波長の光を放射するレーザ装置と、該
レーザ装置のレーザ光の周波数を変換するための変換手
段と、変換されたレーザ光の光路上に配置されたガスセ
ルとを有してこのガスセルでのレーザ光の減衰状態を見
て該セル内の湿度を検知している。(Means for solving the slope problem) In the present invention, a laser device that emits light of a certain wavelength, a conversion means for converting the frequency of the laser beam of the laser device, and a device on the optical path of the converted laser beam are provided. The humidity inside the cell is detected by observing the attenuation state of the laser beam in the gas cell.
（１作 用
レーザ光の周波数を変１ｆＡする光変１ａ手段を有して
いるので、レーザ光の周波数を水蒸気による吸光率の高
い周波数に調整される。(1 action) Since the light changing means 1a is provided to change the frequency of the laser beam by 1 fA, the frequency of the laser beam can be adjusted to a frequency at which the absorption rate by water vapor is high.
（へ）実施例
図は本発明湿度センサを示し、＋１１は１０．６μｍの
波長のレーザ光を放射するＣＯ２レーザ装置、（２）は
例えばＬｉＮｂ０．光導波路Ｍ４遣分有した５ｅｃｏｎ
ｄ ＨａｒｍｏＩＩｉｃ Ｇｅｎｅｒａｔｉｏｎ素子（
以下Ｓ Ｉ−１（コ素子と云う）であり、レーザ光の周
波数を２倍に変換し、波長を１７２にする。（４） （
５）及び［４’ ＋ （５’ １は夫々上記ＳＨＧ素子
（２１（３＋からチェレンコフ放射角をもって放射され
る出射光（７１（７’ ｌを集光するレンズ、（１０）
はレン′ズ（５゛）からのレーザ光を２分割するハーフ
ミラ−を示し、一方のレーザ光はその光強度を検出する
光検知器（８）へ、他方のレーザ光は湿度検知すべきガ
スが導入されるガスセル（６）へ導かれる。（９）は上
記ガスセル（６）からのレーザ光の光強度を検出する光
検知器、（ｌ ｌ！この光検知器（９）での光強度と上
記光検知器（８）での光強度を比較する比較手段であり
、この光強度の差異によりガスセル（６）内のガスの湿
度を導出する。尚、こうした構造において、ハーフミラ
−（１０）と光検出器（８）、ハーフミラ−（１０）と
ガスセル（６）、及びガスセル（６）と光検出器（９）
の間は出来るだけ近接させるか、あるいはレーザ光の減
衰率の小さいグラスファイバー等で光路を形成し。(v) Example diagram shows the humidity sensor of the present invention, +11 is a CO2 laser device that emits a laser beam with a wavelength of 10.6 μm, and (2) is, for example, LiNb0. 5econ with M4 optical waveguides
d HarmoIIic Generation element (
Hereinafter, it is referred to as SI-1 (co-element), which doubles the frequency of the laser beam and makes the wavelength 172. (4) (
5) and [4' + (5' 1 is a lens that condenses the outgoing light (71 (7') emitted from the SHG element (21 (3+) with a Cerenkov radiation angle, (10)
indicates a half mirror that splits the laser beam from the lens (5゛) into two, one laser beam is sent to the photodetector (8) that detects the light intensity, and the other laser beam is sent to the gas whose humidity is to be detected. is introduced into the gas cell (6). (9) is a photodetector that detects the light intensity of the laser beam from the gas cell (6), (l l! The light intensity at this photodetector (9) and the light intensity at the photodetector (8) This is a comparison means for comparing the light intensity, and the humidity of the gas in the gas cell (6) is derived from this difference in light intensity.In addition, in this structure, the half mirror (10), the photodetector (8), the half mirror (10) ) and gas cell (6), and gas cell (6) and photodetector (9)
Either make the space between them as close as possible, or form an optical path using glass fiber, etc., which has a low attenuation rate for laser light.
レーザ光の減衰を印判するようにしなければならない。The attenuation of the laser beam must be taken into account.
またガスセル（６）には測定対象となるガスを強制的に
送り込む機構も必要である。The gas cell (6) also requires a mechanism for forcibly feeding the gas to be measured.
５二のような湿度センサにおいて、力゛スセル（６）内
に湿度測定対象となるガスを送り込んでＣＯ２レーザ装
置（１）から１０．６μｍ波長のレーザ光を出力すると
、このレーザ光はＳＨＧ素子（２） ＋３１で夫々波長
が１／２に変換され、結局波長２６５μｍのレーザ光が
ハーフミラ−（ｌθ）で２分割されて光検知器（８）と
ガスセル（６）へ供給される。水蒸気のレーザ光吸収の
ピーク波長は２．７μｍ付近であるので、ガスセル（６
）に供給された波長２６５μｍのレーザ光はガスセル（
６）内の水蒸気により効率的に吸収される。このときの
ガスセル（６）からの出射光のエネルギーＩはＬａｍｂ
ｅｒｔ−Ｂｅｅｒの法則により
Ｉ＝Ｉｏｅｘｐ （−（ＺＣＬ）
■。；セルへの入射光エネルギー、α：吸収効率、Ｃ・
水蒸気濃度、Ｌ：セル長、
で表わされる。こうしてガスセル（６）から出射された
レーザ光は光検知器（９）へ与えられ、その光強度が検
知される。その後比較手段（１１）で光検知器（８）
（９１での検出強度を比較することにより、ガスセル（
６）内の水蒸気濃度がわかり、これから湿度が演算算出
される。In a humidity sensor such as No. 52, when a gas to be measured for humidity is sent into the force cell (6) and a laser beam with a wavelength of 10.6 μm is output from the CO2 laser device (1), this laser beam passes through the SHG element. (2) Each wavelength is converted to 1/2 at +31, and finally the laser beam with a wavelength of 265 μm is divided into two by a half mirror (lθ) and supplied to the photodetector (8) and the gas cell (6). Since the peak wavelength of laser light absorption of water vapor is around 2.7 μm, the gas cell (6
The laser beam with a wavelength of 265 μm supplied to the gas cell (
6) It is efficiently absorbed by the water vapor inside. At this time, the energy I of the light emitted from the gas cell (6) is Lamb
According to the ert-Beer law, I = Ioexp (-(ZCL)) ■.; Incident light energy to the cell, α: absorption efficiency, C.
Water vapor concentration, L: cell length, is expressed as follows. The laser light emitted from the gas cell (6) in this manner is applied to the photodetector (9), and its light intensity is detected. Thereafter, the comparison means (11) detects the photodetector (8).
(By comparing the detection intensity at 91, the gas cell (
6) The water vapor concentration within is known, and the humidity is calculated from this.
このような湿度センサは信顆性試験用の恒温槽や微生物
培養器内の湿度検知、あるいは住居空間内の湿度検知に
利用出来る。Such a humidity sensor can be used to detect humidity in a constant temperature bath for reliability testing, a microbial incubator, or in a residential space.
（ト）発明の効果
以上述べた如く本発明湿度センサはレーザ光の周波数を
変換する変換手段を設け、水蒸気により吸収され易いレ
ーザ光周波数に変換しているｊ、）で、水蒸気；農度が
レーザ光の践衰に鋭敏に反映され、正確な湿度検知が行
なわれる。また、従来に比してセンサ寿命も長く、消費
電力も少くなる。(G) Effects of the Invention As described above, the humidity sensor of the present invention is equipped with a conversion means for converting the frequency of laser light, and converts the frequency of the laser light to one that is easily absorbed by water vapor. The humidity is sensitively reflected in the decay of the laser beam, allowing accurate humidity detection. Additionally, the sensor lifespan is longer and power consumption is lower than in the past.
図は本発明湿度センサの一実施例プロ・ツク図である。
（１１・・ＣＯ□レーサ装置、＋２１ （３１・・・５
）ＩＧ素子、＋４＋ ！４’ ） （５１（５’ ）・
・レンズ、（６）・・ガスセル、（７）（７゛）・・レ
ーザ光、（８１（９＋・・・光検出器、（１０）・ノ＼
−フミラー、（１１）・・・比較手段。The figure is a schematic diagram of one embodiment of the humidity sensor of the present invention. (11... CO□ laser device, +21 (31...5
) IG element, +4+! 4') (51(5')・
・Lens, (6)...Gas cell, (7) (7゛)...Laser light, (81(9+...Photodetector, (10)・ノ＼
-Humiller, (11)...Comparison means.
Claims (1)
置のレーザ光の周波数を変換するための変換手段と、変
換されたレーザ光の光路上に配置されたガスセルと、を
有して成り、このガスセルでのレーザ光の減衰状態を見
て該セル内の湿度を検知して成る湿度センサ。1) It comprises a laser device that emits light of a certain wavelength, a conversion means for converting the frequency of the laser beam of the laser device, and a gas cell placed on the optical path of the converted laser beam. A humidity sensor detects the humidity inside the gas cell by observing the attenuation state of the laser light in the gas cell.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32461188A JPH02168142A (en) | 1988-12-22 | 1988-12-22 | Humidity sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32461188A JPH02168142A (en) | 1988-12-22 | 1988-12-22 | Humidity sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02168142A true JPH02168142A (en) | 1990-06-28 |
Family
ID=18167752
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32461188A Pending JPH02168142A (en) | 1988-12-22 | 1988-12-22 | Humidity sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02168142A (en) |
-
1988
- 1988-12-22 JP JP32461188A patent/JPH02168142A/en active Pending
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