JP3454173B2 - Optical dust sensor optical system - Google Patents
Optical dust sensor optical systemInfo
- Publication number
- JP3454173B2 JP3454173B2 JP31744398A JP31744398A JP3454173B2 JP 3454173 B2 JP3454173 B2 JP 3454173B2 JP 31744398 A JP31744398 A JP 31744398A JP 31744398 A JP31744398 A JP 31744398A JP 3454173 B2 JP3454173 B2 JP 3454173B2
- Authority
- JP
- Japan
- Prior art keywords
- optical system
- optical
- light
- light source
- dust
- 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.)
- Expired - Fee Related
Links
- 230000003287 optical effect Effects 0.000 title claims description 290
- 239000000428 dust Substances 0.000 title claims description 114
- 238000005259 measurement Methods 0.000 claims description 80
- 238000001514 detection method Methods 0.000 claims description 16
- 239000002131 composite material Substances 0.000 claims description 3
- 230000000694 effects Effects 0.000 description 13
- 239000002245 particle Substances 0.000 description 11
- 230000010287 polarization Effects 0.000 description 11
- 230000008878 coupling Effects 0.000 description 4
- 238000010168 coupling process Methods 0.000 description 4
- 238000005859 coupling reaction Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000007788 liquid Substances 0.000 description 3
- 241000238876 Acari Species 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002040 relaxant effect Effects 0.000 description 1
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ほこり（ダニやカ
ビ等を含む）に光が照射された時に生じるＭｉｅ散乱に
よる受信光強度のレベル変動（減少）によってほこりの
存在を検出する、光学式ほこりセンサの光学系に関する
ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system for detecting the presence of dust by a level fluctuation (reduction) in the received light intensity due to Mie scattering which occurs when dust (including mites and molds) is irradiated with light. The present invention relates to an optical system of a dust sensor.
【０００２】[0002]
【従来の技術】図８は、例えば、水野眞人「液体用パー
ティクルカウンタ」センサ技術、ｖｏｌ．１０，Ｎｏ．
１２，５５−５９（９０）に示された従来のレーザ液中
パーティクルカウンタの光学系の構成を示す構成説明図
である。図において、１０は光源であるレーザダイオー
ド、２０はコリメータレンズ２１と軸外し楕円面鏡２２
からなる照射光学系、３０は集光光学系、４０は光検出
器であるフォトダイオードである。レーザダイオード１
０からの光１００は照射光学系２０によって試料１１０
が流されるセル１２０の位置に絞り込まれる。このよう
にレーザダイオード１０からの光１００が絞り込まれた
焦点位置が測定領域５０（図示せず）である。この時、
試料１１０中にレーザダイオード１０からの光１００の
波長と同程度の粒径を有するほこりが存在していると、
レーザダイオード１０からの光１００はこのほこりによ
ってＭｉｅ散乱される。この散乱光１０１を集光光学系
３０で受光し、フォトダイオード４０の検出部分に集光
する。2. Description of the Related Art FIG. 8 shows, for example, Masato Mizuno "Liquid Particle Counter" sensor technology, vol. 10, No.
It is a structure explanatory view which shows the structure of the optical system of the conventional laser submerged particle counter shown by 12, 55-59 (90). In the figure, 10 is a laser diode as a light source, 20 is a collimator lens 21 and an off-axis elliptical mirror 22.
Is an irradiation optical system, 30 is a condensing optical system, and 40 is a photodiode which is a photodetector. Laser diode 1
The light 100 from 0 is transmitted to the sample 110 by the irradiation optical system 20.
Is narrowed down to the position of the cell 120 where the liquid is flown. The focus position where the light 100 from the laser diode 10 is narrowed down in this way is the measurement region 50 (not shown). At this time,
If there is dust having a particle size similar to the wavelength of the light 100 emitted from the laser diode 10 in the sample 110,
The light 100 from the laser diode 10 is Mie scattered by this dust. The scattered light 101 is received by the condensing optical system 30 and condensed on the detection portion of the photodiode 40.
【０００３】上記のように、従来のレーザ液中パーティ
クルカウンタによれば、測定領域５０に光１００の波長
と同程度の粒径を有するほこりが存在すると、ほこりに
よるＭｉｅ散乱の散乱光１０１をフォトダイオード４０
で受光することができるため、図９に示すようなフォト
ダイオード４０の出力変動（増加）を得ることができる
ので、ほこりを検出することができる。As described above, according to the conventional laser submerged particle counter, when dust having a particle size similar to the wavelength of the light 100 is present in the measurement region 50, the scattered light 101 of Mie scattered by the dust is detected. Diode 40
Since it is possible to receive the light, it is possible to obtain the output fluctuation (increase) of the photodiode 40 as shown in FIG. 9, so that dust can be detected.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、上記し
た従来のレーザ液中パーティクルカウンタは、小さい粒
子を測定するためにレーザダイオード１０を用い、測定
領域５０のエネルギー密度を高めるために、レーザダイ
オード１０からの光１００を照射光学系２０によって測
定領域５０にビーム径が１０μｍ程度以下に絞り込んで
おり、また、図８に示したように構成されているため、
測定領域５０と集光光学系３０でフォトダイオード４０
を見込む位置がずれると十分に散乱光を受光できなくな
り、高い位置合わせ精度が要求されると共に振動等の影
響を受けない構造が必要となるという問題点を有する。However, in the above-mentioned conventional laser liquid particle counter, the laser diode 10 is used to measure small particles, and the laser diode 10 is used to increase the energy density of the measurement region 50. Beam 100 is focused on the measurement region 50 by the irradiation optical system 20 to have a beam diameter of about 10 μm or less, and is configured as shown in FIG.
The measurement area 50 and the condensing optical system 30 make the photodiode 40
There is a problem in that if the position in sight is shifted, scattered light cannot be received sufficiently, high alignment accuracy is required, and a structure that is not affected by vibration or the like is required.
【０００５】本発明は、検出対象のほこりで発生したＭ
ｉｅ散乱による散乱光を直接的に検出器で検出する必要
がなく、各部の設定精度を緩和する光学式ほこりセンサ
光学系を得ることを目的としており、さらに、振動等に
対する信頼性を向上した光学式ほこりセンサ光学系を得
ることを目的としている。In the present invention, M generated in the dust to be detected
The purpose is to obtain an optical dust sensor optical system that relaxes the setting accuracy of each part without the need to directly detect scattered light due to IE scattering with a detector. Furthermore, an optical system with improved reliability against vibration, etc. The purpose is to obtain a formula dust sensor optical system.
【０００６】[0006]
【課題を解決するための手段】この発明の請求項１に係
る光学式ほこりセンサ光学系は、検出対象のほこりの大
きさに対して前方散乱を主とするＭｉｅ散乱を発生させ
る波長の光源と、上記波長の光を検出する光検出器と、
上記光源からの光が絞り込まれ、上記検出対象のほこり
に照射される測定領域と、上記光源からの光を上記測定
領域に絞り込む照射光学系と、上記測定領域付近の所定
の位置に設置され、上記測定領域に絞り込まれた上記光
源からの光を反射させる反射鏡と、上記反射鏡で反射さ
れた光を上記光検出器に導く集光光学系とを備え、上記
検出対象のほこりで発生した上記Ｍｉｅ散乱による上記
光検出器の出力の減少により、上記検出対象のほこりを
検出することを特徴とするものである。According to a first aspect of the present invention, there is provided an optical dust sensor optical system comprising: a light source having a wavelength that causes Mie scattering, which is mainly forward scattering with respect to the size of dust to be detected. A photodetector for detecting light of the above wavelength,
The light from the light source is narrowed down, the measurement area irradiated to the dust of the detection target, an irradiation optical system that narrows the light from the light source to the measurement area, and is installed at a predetermined position near the measurement area, A reflecting mirror that reflects the light from the light source that is narrowed down to the measurement region, and a condensing optical system that guides the light reflected by the reflecting mirror to the photodetector, are generated in the dust of the detection target. It is characterized in that the dust of the detection target is detected by reducing the output of the photodetector due to the Mie scattering.
【０００７】また、この発明の請求項２に係る光学式ほ
こりセンサ光学系は、上記照射光学系と集光光学系に代
えて、上記照射光学系として機能すると共に上記集光光
学系としても機能する共通の共用光学系と、上記光源か
らの光を上記共用光学系に導くと共に上記反射鏡で反射
されて上記共用光学系に入射した光を上記光検出器に導
く、上記光源から上記共用光学系への光路と上記共用光
学系から上記光検出器への光路を分離する光学素子とを
備えたことを特徴とするものである。The optical dust sensor optical system according to a second aspect of the present invention functions as the irradiation optical system and the condensing optical system instead of the irradiation optical system and the condensing optical system. Common optical system and a common optical system for guiding light from the light source to the common optical system and for guiding light reflected by the reflecting mirror and incident on the common optical system to the photodetector, the common optical system from the light source An optical element for separating the optical path to the system and the optical path from the shared optical system to the photodetector is provided.
【０００８】また、この発明の請求項３に係る光学式ほ
こりセンサ光学系は、上記共用光学系を上記測定領域に
後側焦点を有し、上記光源からの光を上記測定領域に集
光させるよう形成し、上記反射鏡を上記後側焦点位置に
設置される平面鏡としたことを特徴とするものである。According to a third aspect of the present invention, in the optical dust sensor optical system, the shared optical system has a rear focal point in the measurement area, and collects the light from the light source in the measurement area. Thus, the reflecting mirror is a plane mirror installed at the rear focal position.
【０００９】また、この発明の請求項４に係る光学式ほ
こりセンサ光学系は、上記共用光学系を上記測定領域に
後側焦点を有し、上記光源からの光を上記測定領域に集
光させるよう形成し、上記反射鏡を上記後側焦点を中心
とする球面内面で形成される球面鏡としたことを特徴と
するものである。According to a fourth aspect of the present invention, in the optical dust sensor optical system, the shared optical system has a rear focal point in the measurement area, and the light from the light source is condensed in the measurement area. Thus, the reflecting mirror is a spherical mirror formed by an inner surface of a spherical surface centered on the rear focal point.
【００１０】また、この発明の請求項５に係る光学式ほ
こりセンサ光学系は、上記共用光学系を上記光源からの
光を平行光として上記測定領域に絞り込むコリメート光
学系とし、上記反射鏡を平面鏡としたことを特徴とする
ものである。According to a fifth aspect of the present invention, in the optical dust sensor optical system, the common optical system is a collimating optical system that narrows the light from the light source into parallel light and narrows it into the measurement area, and the reflecting mirror is a plane mirror. It is characterized by that.
【００１１】また、この発明の請求項６に係る光学式ほ
こりセンサ光学系は、上記共用光学系と上記光学素子に
代えて、上記共用光学系と上記光学素子のそれぞれの機
能を有する一体化した複合光学系を備えたことを特徴と
するものである。In the optical dust sensor optical system according to claim 6 of the present invention, instead of the shared optical system and the optical element, the shared optical system and the optical element are integrated to have respective functions. It is characterized by having a composite optical system.
【００１２】また、この発明の請求項７に係る光学式ほ
こりセンサ光学系は、上記光源と光検出器と共用光学系
と光学素子に代えて、検出対象のほこりの大きさに対し
て前方散乱を主とするＭｉｅ散乱を発生させる波長の光
源となるレーザダイオードと、上記レーザダイオードか
らの光を上記測定領域に絞り込む対物レンズと、上記反
射鏡で反射されて上記対物レンズに入射した上記レーザ
ダイオードからの光を検出する光検出器となるフォトダ
イオードとを有する光ピックアップ光学系を備え、上記
対物レンズの後側焦点位置を上記測定領域とし、上記反
射鏡を上記対物レンズの後側焦点位置に設置される平面
鏡としたことを特徴とするものである。Further, in the optical dust sensor optical system according to claim 7 of the present invention, instead of the light source, the photodetector, the common optical system and the optical element, forward scatter with respect to the size of dust to be detected. A laser diode serving as a light source of a wavelength that causes Mie scattering, an objective lens that narrows the light from the laser diode to the measurement region, and the laser diode that is reflected by the reflecting mirror and enters the objective lens. An optical pickup optical system having a photodiode serving as a photodetector for detecting light from the objective lens, the rear focal position of the objective lens as the measurement area, and the reflecting mirror at the rear focal position of the objective lens. The feature is that it is a plane mirror to be installed.
【００１３】また、この発明の請求項８に係る光学式ほ
こりセンサ光学系は、上記光源と光検出器と共用光学系
と光学素子に代えて、検出対象のほこりの大きさに対し
て前方散乱を主とするＭｉｅ散乱を発生させる波長の光
源となるレーザダイオードと、上記レーザダイオードか
らの光を上記測定領域に絞り込む対物レンズと、上記反
射鏡で反射されて上記対物レンズに入射した上記レーザ
ダイオードからの光を検出する光検出器となるフォトダ
イオードとを有する光ピックアップ光学系を備え、上記
対物レンズの後側焦点位置を上記測定領域とし、上記反
射鏡を上記対物レンズの後側焦点を中心とする球面内面
で形成される球面鏡としたことを特徴とするものであ
る。Further, in the optical dust sensor optical system according to claim 8 of the present invention, instead of the light source, the photodetector, the common optical system and the optical element, forward scattering is performed with respect to the size of the dust to be detected. A laser diode serving as a light source of a wavelength that causes Mie scattering, an objective lens that narrows the light from the laser diode to the measurement region, and the laser diode that is reflected by the reflecting mirror and enters the objective lens. An optical pickup optical system having a photodiode serving as a photodetector for detecting light from the objective lens, the rear focal point of the objective lens is the measurement area, and the reflecting mirror is centered on the rear focal point of the objective lens. And a spherical mirror formed by the inner surface of the spherical surface.
【００１４】[0014]
【発明の実施の形態】実施の形態１．図１は本発明によ
る光学式ほこりセンサ光学系の実施の形態１を示す構成
説明図である。図１において、６０は照射光学系として
用いると共に集光光学系としても用いられる共用光学
系、７０は共用光学系６０の後側焦点位置に相当する測
定領域５０の位置に設置された平面鏡、８０は光源１０
からの光１００を共用光学系６０に導くと共に共用光学
系６０からの光を光検出器４０に導く光学素子である。
なお、図１において、図８と同一または相当部分には、
同一符号を付している。BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. FIG. 1 is a configuration explanatory view showing a first embodiment of an optical dust sensor optical system according to the present invention. In FIG. 1, reference numeral 60 denotes a shared optical system which is used not only as an irradiation optical system but also as a condensing optical system, 70 denotes a plane mirror installed at a position of a measurement region 50 corresponding to a rear focal position of the shared optical system 60, and 80. Is the light source 10
It is an optical element that guides the light 100 from the common optical system 60 to the common optical system 60 and guides the light from the common optical system 60 to the photodetector 40.
In addition, in FIG. 1, the same or corresponding portions as in FIG.
The same reference numerals are attached.
【００１５】次に、図１に示した光学式ほこりセンサ光
学系の動作について説明する。光源１０から出た光１０
０は、照射光学系と集光光学系の共用光学系６０によっ
て測定領域５０に絞り込まれる。絞り込まれた光は平面
鏡７０によって反射されて戻され、再び共用光学系６０
によって受光されて集光され、光学素子８０によって光
検出器４０に導かれ受光される。一方、この測定領域５
０に光源１０の波長と同程度の大きさのほこりが到来し
た時、光源１０からの光１００はほこりによって散乱さ
れる。図２に光源１０の波長を０．７８μｍとした時の
粒径１μｍのほこりによる散乱強度の散乱角依存性を示
す。図２に示したように散乱源の粒径（２Ａとする）が
光の波長（λとする）と同程度以上（散乱係数α＝２π
Ａ／λが４程度）である場合のＭｉｅ散乱においては、
散乱光のほとんどが前方に散乱され、後方（光の到来方
向）には極僅かしか散乱されないことが分かる。従っ
て、直接的に共用光学系６０へ戻る散乱光はほとんど無
く、前方に散乱されたものが平面鏡７０によって反射さ
れて戻されることになる。しかしながら、前方散乱の角
度範囲のうち共用光学系６０に戻されて再び有効に入る
可能性のある角度範囲は限られ、さらに、平面鏡７０に
よって反射され、再度ほこりで散乱されるため、共用光
学系６０へ戻る前方散乱光は激減する。このため、測定
領域５０に絞り込まれた光１００のうち測定領域５０に
到来したほこりによって散乱された光は共用光学系６０
にほとんど戻らず、光検出器４０で受光されないため、
光検出器４０からの出力には図３に示すようなレベル変
動（減少）が生じる。Next, the operation of the optical dust sensor optical system shown in FIG. 1 will be described. Light 10 emitted from light source 10
0 is narrowed down to the measurement region 50 by the shared optical system 60 of the irradiation optical system and the condensing optical system. The narrowed light is reflected by the plane mirror 70 and returned to the common optical system 60 again.
The light is received and condensed by the optical element 80 and guided to the photodetector 40 by the optical element 80 to be received. On the other hand, this measurement area 5
When dust of the same size as the wavelength of the light source 10 arrives at 0, the light 100 from the light source 10 is scattered by the dust. FIG. 2 shows the scattering angle dependence of the scattering intensity due to dust having a particle size of 1 μm when the wavelength of the light source 10 is 0.78 μm. As shown in FIG. 2, the particle diameter of the scattering source (2A) is equal to or larger than the wavelength of light (λ) (scattering coefficient α = 2π).
In Mie scattering when A / λ is about 4),
It can be seen that most of the scattered light is scattered forward, and only very slightly backward (direction of arrival of light). Therefore, almost no scattered light directly returns to the shared optical system 60, and what is scattered forward is reflected by the plane mirror 70 and returned. However, the angle range of the forward scattering angle range that can be returned to the shared optical system 60 and re-entered is limited, and further, the angle range of the forward scattering is reflected by the plane mirror 70 and scattered again by the dust, and therefore, the shared optical system. The forward scattered light returning to 60 is drastically reduced. Therefore, of the light 100 narrowed down in the measurement area 50, the light scattered by the dust reaching the measurement area 50 is shared optical system 60.
Since it does not return to the photodetector 40 and is not received by the photodetector 40,
The output from the photodetector 40 undergoes level fluctuation (decrease) as shown in FIG.
【００１６】例えば、光源１０の波長を０．７８μｍと
し、共用光学系６０の開口数ＮＡを０．４５とすると、
次式から絞り込まれたところでのスポット径は２．１μ
ｍ程度となる。
Ａspot＝２．４４λ／２・ＮＡ
一方、ほこりの粒径を１μｍとすると、スポットサイズ
が３．４６μｍ2 であるのに対してほこりの断面積が
０．７９μｍ2 であるので、図３に示した出力の減少は
２３％程度にもなり、ほこりの検出が可能であることが
分かる。For example, if the wavelength of the light source 10 is 0.78 μm and the numerical aperture NA of the shared optical system 60 is 0.45,
The spot diameter when narrowed down from the following formula is 2.1μ
It will be about m. A spot = 2.44λ / 2 · NA On the other hand, assuming that the particle size of dust is 1 μm, the spot size is 3.46 μm 2 whereas the cross-sectional area of dust is 0.79 μm 2 . The output reduction shown is about 23%, which shows that dust can be detected.
【００１７】以上は共用光学系を備えた光学式ほこりセ
ンサ光学系の構成説明図を示して、検出対象のほこりの
大きさに対して前方散乱を主とするＭｉｅ散乱を発生さ
せる波長の光源を用い、測定領域に絞り込まれた上記光
源からの光を測定領域付近の所定の位置に設置された反
射鏡で反射し、上記検出対象のほこりで発生した上記Ｍ
ｉｅ散乱による光検出器の出力の減少により、上記検出
対象のほこりを検出する一実施の形態を説明したが、共
用光学系の機能を別々に担う個別の照射光学系と集光光
学系で構成できることは言うまでもない。The above is a configuration explanatory view of an optical dust sensor optical system having a shared optical system, and shows a light source having a wavelength that causes Mie scattering mainly due to forward scattering with respect to the size of dust to be detected. The light from the light source narrowed down to the measurement region is reflected by a reflecting mirror installed at a predetermined position near the measurement region, and the M generated in the dust of the detection target is used.
One embodiment has been described in which the dust of the detection target is detected by the reduction of the output of the photodetector due to the IE scattering. However, the irradiation optical system and the condensing optical system separately function as the shared optical system. It goes without saying that you can do it.
【００１８】以上のように、検出対象のほこりの大きさ
に対して前方散乱を主とするＭｉｅ散乱を発生させる波
長の光源を用い、測定領域に絞り込まれた上記光源から
の光を測定領域付近の所定の位置に設置された反射鏡で
反射し、上記検出対象のほこりで発生した上記Ｍｉｅ散
乱による光検出器の出力の減少により、上記検出対象の
ほこりを検出するので、検出対象のほこりで発生したＭ
ｉｅ散乱による散乱光を直接的に検出器で検出する必要
がなく、光学式ほこりセンサ光学系の各部の設定精度を
緩和できる。さらに、共用光学系と光学素子とを用いて
構成することにより、照射光学系と集光光学系が同軸に
なり、振動等に対する信頼性を向上でき、また、小型
化、軽量化できる。また、図１に示したように、共用光
学系を測定領域に後側焦点を有し、光源からの光を上記
測定領域に集光させるよう形成し、上記後側焦点位置に
平面鏡を設置したので、検出対象のほこりで発生するＭ
ｉｅ散乱による前方散乱光の内、平面鏡で反射されて共
用光学系へ入射可能となる光の有効角度を狭くでき、光
検出器の出力の減少を顕著にして精度の良いほこりの検
出を可能にする。As described above, a light source having a wavelength that causes Mie scattering, which is mainly forward scattering, with respect to the size of dust to be detected is used, and the light from the light source narrowed down to the measurement area is measured near the measurement area. Is reflected by a reflecting mirror installed at a predetermined position, and the output of the photodetector is reduced due to the Mie scattering generated in the dust of the detection target, and the dust of the detection target is detected. Occurred M
It is not necessary to directly detect scattered light due to ie scattering by a detector, and the setting accuracy of each part of the optical dust sensor optical system can be relaxed. Further, by using the shared optical system and the optical element, the irradiation optical system and the condensing optical system are coaxial with each other, the reliability against vibration and the like can be improved, and the size and weight can be reduced. In addition, as shown in FIG. 1, the shared optical system has a rear focal point in the measurement region, is formed so as to focus the light from the light source on the measurement region, and a plane mirror is installed at the rear focal position. Therefore, M generated in the dust to be detected
Of the forward scattered light due to ie scattering, the effective angle of the light that is reflected by the plane mirror and can enter the shared optical system can be narrowed, and the output of the photodetector can be significantly reduced to enable accurate dust detection. To do.
【００１９】実施の形態２．図４は本発明による光学式
ほこりセンサ光学系の実施の形態２を示す構成説明図で
ある。図４において、７１は共用光学系６０の後側焦点
位置に設定される測定領域５０付近に置かれた球面鏡で
あり、共用光学系６０の後側焦点を中心とする球面で形
成されている。なお、図４において、図１と同一または
相当部分には、同一符号を付している。Embodiment 2. FIG. 4 is a structural explanatory view showing Embodiment 2 of the optical system for the optical dust sensor according to the present invention. In FIG. 4, reference numeral 71 denotes a spherical mirror placed in the vicinity of the measurement area 50 set at the rear focus position of the shared optical system 60, and is formed of a spherical surface having the rear focus of the shared optical system 60 as the center. In FIG. 4, the same or corresponding parts as in FIG. 1 are designated by the same reference numerals.
【００２０】次に、図４に示した光学式ほこりセンサ光
学系の動作について説明する。光源１０から出た光１０
０は、照射光学系と集光光学系の共用光学系６０によっ
て測定領域５０に絞り込まれる。絞り込まれた光は球面
鏡７１によって反射されて戻され、再び共用光学系６０
によって受光されて集光され、光学素子８０によって光
検出器４０に導かれ受光される。一方、この測定領域５
０に光源１０の波長と同程度の大きさを有するほこりが
到来した時、光源１０からの光１００はほこりによって
散乱される。ここで、平面鏡７０に代えて球面鏡７１を
用いる場合にも、発明の実施の形態１で述べたような条
件でのＭｉｅ散乱の説明ように、測定領域５０に導かれ
た光１００のうち測定領域５０に到来したほこりによっ
て散乱された光は共用光学系６０にほとんど戻らないた
め、光検出器４０で受光されない。このため、光検出器
４０からの出力には図３に示すようなレベル変動（減
少）が生じる。Next, the operation of the optical dust sensor optical system shown in FIG. 4 will be described. Light 10 emitted from light source 10
0 is narrowed down to the measurement region 50 by the shared optical system 60 of the irradiation optical system and the condensing optical system. The narrowed light is reflected by the spherical mirror 71 and returned, and the shared optical system 60 again.
The light is received and condensed by the optical element 80 and guided to the photodetector 40 by the optical element 80 to be received. On the other hand, this measurement area 5
When a dust having a size as large as the wavelength of the light source 10 arrives at 0, the light 100 from the light source 10 is scattered by the dust. Here, even when the spherical mirror 71 is used instead of the plane mirror 70, the measurement area of the light 100 guided to the measurement area 50 is as described in the Mie scattering under the conditions described in the first embodiment of the invention. The light scattered by the dust arriving at 50 hardly returns to the shared optical system 60, and thus is not received by the photodetector 40. Therefore, the output from the photodetector 40 undergoes level fluctuation (decrease) as shown in FIG.
【００２１】従って、前記実施の形態１と同様の効果を
奏する他、反射鏡を共用光学系の後側焦点を中心とする
球面内面で形成される球面鏡としたので、検出対象のほ
こりで発生したＭｉｅ散乱による散乱光以外の測定領域
に集光された光源からの光を確実に共用光学系へ戻すよ
う反射させることができる効果がある。Therefore, in addition to the effect similar to that of the first embodiment, since the reflecting mirror is a spherical mirror formed by the inner surface of the spherical surface centering on the rear focal point of the shared optical system, it is generated by the dust of the object to be detected. There is an effect that the light from the light source condensed in the measurement region other than the scattered light due to Mie scattering can be reflected so as to surely return to the shared optical system.
【００２２】実施の形態３．図５は本発明による光学式
ほこりセンサ光学系の実施の形態３を示す構成説明図で
ある。図５において、６１は光源１０からの光１００を
コリメートして測定領域５０に導くと共に測定領域５０
からの戻り光を光学素子８０を介して光検出器４０に集
光する共用光学系、７０は測定領域５０付近に置かれた
平面鏡である。なお、図５において、図１と同一または
相当部分には、同一符号を付している。Embodiment 3. FIG. 5 is a structural explanatory view showing the third embodiment of the optical system for the optical dust sensor according to the present invention. In FIG. 5, reference numeral 61 collimates the light 100 from the light source 10 to guide it to the measurement area 50 and
A common optical system for condensing the return light from the optical detector 80 through the optical element 80, and 70 is a plane mirror placed near the measurement region 50. In FIG. 5, parts that are the same as or correspond to those in FIG. 1 are given the same reference numerals.
【００２３】次に、図５に示した光学式ほこりセンサ光
学系の動作について説明する。光源１０から出た光は、
照射光学系と集光光学系の共用光学系６１によってコリ
メートされて測定領域５０に導かれる。測定領域５０に
導かれた光は平面鏡７０によって反射され、共用光学系
６１によって受光され、光学素子８０によって光検出器
４０に導かれ受光される。一方、この測定領域５０に光
源１０の波長と同程度の大きさを有するほこりが到来し
た時、光源１０からの光１００はほこりによって散乱さ
れる。ここで、共用光学系６１によってコリメートされ
た光をほこりに照射した場合にも、発明の実施の形態１
で述べたような条件でのＭｉｅ散乱の説明のように、測
定領域５０に導かれた光１００のうち測定領域５０に到
来したほこりによって散乱された光は共用光学系６１に
ほとんど戻らないため、光検出器４０で受光されない。
このため、光検出器４０からの出力には図３に示すよう
なレベル変動（減少）が生じる。Next, the operation of the optical dust sensor optical system shown in FIG. 5 will be described. The light emitted from the light source 10 is
It is collimated by the shared optical system 61 of the irradiation optical system and the condensing optical system and guided to the measurement region 50. The light guided to the measurement region 50 is reflected by the plane mirror 70, received by the shared optical system 61, and guided by the optical element 80 to the photodetector 40 and received. On the other hand, when dust having a size similar to the wavelength of the light source 10 arrives at the measurement region 50, the light 100 from the light source 10 is scattered by the dust. Here, even when dust is irradiated with the light collimated by the shared optical system 61, the first embodiment of the present invention
As described in the Mie scattering under the conditions described in (1), the light scattered by the dust reaching the measurement region 50 among the light 100 guided to the measurement region 50 hardly returns to the shared optical system 61. The light is not received by the photodetector 40.
Therefore, the output from the photodetector 40 undergoes level fluctuation (decrease) as shown in FIG.
【００２４】従って、前記実施の形態１と同様の効果を
奏する他、共用光学系を光源からの光を平行光として測
定領域に絞り込むコリメート光学系とし、反射鏡を平面
鏡としたので、光学式ほこりセンサ光学系の反射鏡ほ
か、各部の設定精度をより緩和し、振動等に対する信頼
性をより向上できる。Therefore, in addition to the same effects as in the first embodiment, the common optical system is a collimating optical system that narrows the light from the light source into parallel light in the measurement area, and the reflecting mirror is a plane mirror. The setting accuracy of each part other than the reflecting mirror of the sensor optical system can be further relaxed, and the reliability against vibration and the like can be further improved.
【００２５】なお、以上の実施の形態１〜３で用いる光
学素子８０は、例えば、偏光ビームスプリッタ等を用い
た複数の光学素子からなるものであっても良く、上記の
ような光源からの光を共用光学系に導くと共に共用光学
系で導かれた反射鏡などからの戻り光を光検出器に導く
機能を有するものであれば良い。また、以上の実施の形
態１〜３では、照射光学系と集光光学系の共用光学系を
模式的に単レンズで図示しているが、組み合せレンズ等
でも良い。さらに、以上の実施の形態１〜３では、光学
素子と共用光学系を分離した機能として模式的に別に図
示しているが、それぞれの機能を併せ持つ複合光学系で
一体化して実現したものでも良い。このようにすること
により、光学式ほこりセンサ光学系をコンパクトに構成
でき、振動等に対する信頼性を向上できるという効果を
奏する。The optical element 80 used in the above first to third embodiments may be composed of a plurality of optical elements using, for example, a polarization beam splitter, and the light from the light source as described above may be used. As long as it has a function of guiding the light to the common optical system and also guiding the return light from the reflecting mirror or the like guided by the common optical system to the photodetector. Further, in the above-described first to third embodiments, the shared optical system of the irradiation optical system and the condensing optical system is schematically shown by a single lens, but a combination lens or the like may be used. Furthermore, in the above-described first to third embodiments, the functions of the optical element and the shared optical system are shown separately as separate functions, but they may be realized by being integrated by a composite optical system having both functions. . By doing so, the optical dust sensor optical system can be made compact, and the reliability against vibration and the like can be improved.
【００２６】実施の形態４．図６は本発明による光学式
ほこりセンサ光学系の実施の形態４を示す構成説明図で
ある。図６において、９０はピックアップ光学系、７０
は測定領域５０付近に置かれた平面鏡である。なお、図
６において、図１と同一または相当部分には、同一符号
を付している。Fourth Embodiment FIG. 6 is a structural explanatory view showing Embodiment 4 of the optical system for an optical dust sensor according to the present invention. In FIG. 6, 90 is a pickup optical system, and 70
Is a plane mirror placed near the measurement area 50. In FIG. 6, the same or corresponding parts as those in FIG. 1 are designated by the same reference numerals.
【００２７】次に、図６に示した光学式ほこりセンサ光
学系の動作について説明する。ピックアップ光学系９０
は、光源であるレーザダイオード１０からの偏光された
光１００が結合レンズ９１でコリメートされた後、偏光
ビームスプリッタ９２を透過し、対物レンズ９３で測定
領域５０に絞り込まれる。絞り込まれた光は対物レンズ
９３の焦点位置に置かれた平面鏡７０によって反射され
る。反射された光１００は対物レンズ９３によってコリ
メートされた後、偏光ビームスプリッタ９２、偏光ビー
ムスプリッタ９４で反射され、集光レンズ９５で集光さ
れてフォトダイオード４０に導かれ受光される。なお、
ここでは、ピックアップ光学系として機能するために設
けられた制御信号用の集光レンズ９６とフォトダイオー
ド４１は用いる必要はない。一方、この測定領域５０に
レーザダイオード１０の波長と同程度の大きさを有する
ほこりが到来した時、レーザダイオード１０からの光１
００はほこりによって散乱される。ここで、発明の実施
の形態１で述べたような条件でのＭｉｅ散乱の説明よう
に、測定領域５０に導かれた光１００のうち測定領域５
０に到来したほこりによって散乱された光は対物レンズ
９３にほとんど戻らないため、フォトダイオード４０で
受光されない。このため、フォトダイオード４０からの
出力には図３に示すようなレベル変動（減少）が生じ
る。Next, the operation of the optical dust sensor optical system shown in FIG. 6 will be described. Pickup optical system 90
After the polarized light 100 from the laser diode 10 as the light source is collimated by the coupling lens 91, it is transmitted through the polarization beam splitter 92 and is narrowed down to the measurement region 50 by the objective lens 93. The narrowed light is reflected by the plane mirror 70 placed at the focal position of the objective lens 93. The reflected light 100 is collimated by the objective lens 93, reflected by the polarization beam splitter 92 and the polarization beam splitter 94, condensed by the condenser lens 95, guided to the photodiode 40, and received. In addition,
Here, it is not necessary to use the condensing lens 96 for the control signal and the photodiode 41 which are provided to function as the pickup optical system. On the other hand, when dust having a size similar to the wavelength of the laser diode 10 arrives at the measurement region 50, the light 1 from the laser diode 10
00 is scattered by dust. Here, as described in the Mie scattering under the conditions described in the first embodiment of the invention, the measurement region 5 of the light 100 guided to the measurement region 50 is measured.
The light scattered by the dust that reaches 0 is hardly returned to the objective lens 93, and thus is not received by the photodiode 40. Therefore, the output from the photodiode 40 undergoes level fluctuation (decrease) as shown in FIG.
【００２８】従って、前記実施の形態１と同様の効果を
奏する他、上記のように、検出対象のほこりの大きさに
対して前方散乱を主とするＭｉｅ散乱を発生させる波長
の光源となるレーザダイオードと、レーザダイオードか
らの光を測定領域に絞り込む対物レンズと、平面鏡で反
射されて対物レンズに入射したレーザダイオードからの
光を検出する光検出器となるフォトダイオードとを有す
る光ピックアップ光学系を用い、対物レンズの後側焦点
位置を測定領域とし、対物レンズの後側焦点位置に平面
鏡を設置したので、光学式ほこりセンサ光学系をコンパ
クトに構成でき、かつ、量産製品である光ピックアップ
光学系の流用により低価格化できるという効果がある。Therefore, in addition to the effect similar to that of the first embodiment, as described above, a laser serving as a light source having a wavelength for generating Mie scattering mainly due to forward scattering with respect to the size of dust to be detected. An optical pickup optical system having a diode, an objective lens that narrows the light from the laser diode to a measurement region, and a photodiode that serves as a photodetector that detects the light from the laser diode that is reflected by a plane mirror and enters the objective lens. Since the back focal position of the objective lens is used as the measurement area and the plane mirror is installed at the rear focal position of the objective lens, the optical dust sensor optical system can be compactly constructed and the optical pickup optical system is a mass-produced product. There is an effect that the price can be reduced by diverting.
【００２９】実施の形態５．図７は本発明による光学式
ほこりセンサ光学系の実施の形態４を示す構成説明図で
ある。図７において、９０はピックアップ光学系、７１
は対物レンズ９３の後側焦点位置に設定される測定領域
５０付近に置かれた球面鏡であり、対物レンズ９３の後
側焦点を中心とする球面で形成されている。なお、図７
において、図６と同一または相当部分には、同一符号を
付している。Embodiment 5. FIG. 7 is a structural explanatory view showing Embodiment 4 of the optical system for an optical dust sensor according to the present invention. In FIG. 7, reference numeral 90 denotes a pickup optical system, 71
Is a spherical mirror placed in the vicinity of the measurement area 50 which is set at the rear focus position of the objective lens 93, and is formed of a spherical surface centering on the rear focus of the objective lens 93. Note that FIG.
6, the same or corresponding parts as in FIG. 6 are designated by the same reference numerals.
【００３０】次に、図７に示した光学式ほこりセンサ光
学系の動作について説明する。ピックアップ光学系９０
は、光源であるレーザダイオード１０からの偏光された
光１００が結合レンズ９１でコリメートされた後、偏光
ビームスプリッタ９２を透過し、対物レンズ９３で測定
領域５０に絞り込まれる。絞り込まれた光は球面鏡７１
によって反射される。反射された光１００は対物レンズ
９３によってコリメートされた後、偏光ビームスプリッ
タ９２、偏光ビームスプリッタ９４で反射され、集光レ
ンズ９５で集光されてフォトダイオード４０に導かれ受
光される。なお、ここでは、ピックアップ光学系として
機能するために設けられた制御信号用の集光レンズ９６
とフォトダイオード４１は用いる必要はない。一方、こ
の測定領域５０にレーザダイオード１０の波長と同程度
の大きさを有するほこりが到来した時、レーザダイオー
ド１０からの光１００はほこりによって散乱される。こ
こで、発明の実施の形態１で述べたような条件でのＭｉ
ｅ散乱の説明のように、測定領域５０に導かれた光１０
０のうち測定領域５０に到来したほこりによって散乱さ
れた光は対物レンズ９３にほとんど戻らないため、フォ
トダイオード４０で受光されない。このため、フォトダ
イオード４０からの出力には図３に示すようなレベル変
動（減少）が生じる。Next, the operation of the optical dust sensor optical system shown in FIG. 7 will be described. Pickup optical system 90
After the polarized light 100 from the laser diode 10 as the light source is collimated by the coupling lens 91, it is transmitted through the polarization beam splitter 92 and is narrowed down to the measurement region 50 by the objective lens 93. The focused light is a spherical mirror 71.
Reflected by. The reflected light 100 is collimated by the objective lens 93, reflected by the polarization beam splitter 92 and the polarization beam splitter 94, condensed by the condenser lens 95, guided to the photodiode 40, and received. It should be noted that here, a condensing lens 96 for a control signal provided to function as a pickup optical system.
The photodiode 41 need not be used. On the other hand, when dust having the same size as the wavelength of the laser diode 10 arrives at the measurement region 50, the light 100 from the laser diode 10 is scattered by the dust. Here, Mi under the conditions described in the first embodiment of the invention
As described for e-scattering, the light 10 guided to the measurement region 50 is
The light scattered by dust that has reached the measurement region 50 out of 0 hardly returns to the objective lens 93, and thus is not received by the photodiode 40. Therefore, the output from the photodiode 40 undergoes level fluctuation (decrease) as shown in FIG.
【００３１】従って、前記実施の形態２と同様の効果を
奏する他、上記の実施の形態４と同様に、光学式ほこり
センサ光学系をコンパクトに構成でき、かつ、量産製品
である光ピックアップ光学系の流用により低価格化でき
るという効果がある。Therefore, in addition to the same effects as the second embodiment, the optical dust sensor optical system can be compactly constructed and the mass production optical pickup optical system can be realized as in the fourth embodiment. There is an effect that the price can be reduced by diverting.
【００３２】なお、上記の実施の形態４および実施の形
態５では、ピックアップ光学系９０として、光源である
レーザダイオード１０、結合レンズ９１、偏光ビームス
プリッタ９２、対物レンズ９３、偏光ビームスプリッタ
９４、集光レンズ９５、フォトダイオード４０、制御信
号用の集光レンズ９６、及び、制御信号用のフォトダイ
オード４１で構成されているものを例示して説明した
が、この構成のものに限るものではなく、所望の波長の
レーザダイオード光源からの光を測定領域へ絞り込み、
測定領域付近に設置した反射鏡で反射されて戻された光
をフォトダイオードで受光して出力する方式のピックア
ップ光学系であれば良く、上記実施の形態４又は実施の
形態５と同様の効果を奏する。In the fourth and fifth embodiments, as the pickup optical system 90, the laser diode 10, which is the light source, the coupling lens 91, the polarization beam splitter 92, the objective lens 93, the polarization beam splitter 94, Although the optical lens 95, the photodiode 40, the condensing lens 96 for the control signal, and the photodiode 41 for the control signal have been described as an example, the present invention is not limited to this configuration. Narrow the light from the laser diode light source of the desired wavelength to the measurement area,
Any pickup optical system may be used as long as it is a system in which a photodiode receives and outputs the light reflected and returned by a reflecting mirror installed in the vicinity of the measurement region, and the same effect as that of the above-described fourth or fifth embodiment is obtained. Play.
【００３３】[0033]
【発明の効果】本発明は、以上説明したように構成され
ているので、以下に記載されているような効果を奏す
る。Since the present invention is constructed as described above, it has the following effects.
【００３４】検出対象のほこりの大きさに対して前方散
乱を主とするＭｉｅ散乱を発生させる波長の光源を用
い、測定領域に絞り込まれた上記光源からの光を測定領
域付近の所定の位置に設置された反射鏡で反射し、上記
検出対象のほこりで発生した上記Ｍｉｅ散乱による光検
出器の出力の減少により、上記検出対象のほこりを検出
するので、検出対象のほこりで発生したＭｉｅ散乱によ
る散乱光を直接的に検出器で検出する必要がなく、光学
式ほこりセンサ光学系の各部の設定精度を緩和するとい
う効果を奏する。A light source having a wavelength that causes Mie scattering, which is mainly forward scattering, with respect to the size of dust to be detected is used, and the light from the light source narrowed down in the measurement region is moved to a predetermined position near the measurement region. Due to the reduction of the output of the photodetector due to the Mie scattering generated by the dust of the detection target, which is reflected by the installed reflection mirror, the dust of the detection target is detected, so that the Mie scattering generated by the dust of the detection target It is not necessary to directly detect the scattered light with the detector, and the effect of relaxing the setting accuracy of each part of the optical dust sensor optical system is obtained.
【００３５】さらに、照射光学系と集光光学系に代え
て、照射光学系として機能すると共に集光光学系として
も機能する共通の共用光学系と、光源から上記共用光学
系への光路と上記共用光学系から光検出器への光路を分
離する光学素子とを備えたので、照射光学系と集光光学
系が同軸になり、光学式ほこりセンサ光学系の振動等に
対する信頼性を向上でき、また、小型化できるという効
果を奏する。Further, instead of the irradiation optical system and the condensing optical system, a common shared optical system which functions as an irradiation optical system and also as a condensing optical system, an optical path from the light source to the common optical system, and the above Since it has an optical element that separates the optical path from the shared optical system to the photodetector, the irradiation optical system and the condensing optical system are coaxial, and the reliability of the optical dust sensor optical system against vibration etc. can be improved, Moreover, there is an effect that the size can be reduced.
【００３６】また、共用光学系を測定領域に後側焦点を
有し、光源からの光を上記測定領域に集光させるよう形
成し、上記測定領域付近の所定の位置に上記光源からの
光を反射させる反射鏡を設置したので、検出対象のほこ
りで発生するＭｉｅ散乱による前方散乱光の内、反射鏡
で反射されて共用光学系へ入射可能となる光の有効角度
を狭くでき、光検出器の出力の減少を顕著にして精度の
良いほこりの検出を可能にするという効果を奏する。Further, the shared optical system has a rear focal point in the measurement area and is formed so as to focus the light from the light source on the measurement area, and the light from the light source is placed at a predetermined position near the measurement area. Since a reflecting mirror for reflecting light is installed, the effective angle of the light that is reflected by the reflecting mirror and can enter the shared optical system can be narrowed out of the forward scattered light due to Mie scattering generated in the dust of the detection target. There is an effect that the decrease of the output of (1) is remarkable and the dust can be detected with high accuracy.
【００３７】また、共用光学系を光源からの光を平行光
として測定領域に絞り込むコリメート光学系とし、反射
鏡を平面鏡としたので、光学式ほこりセンサ光学系の反
射鏡ほか、各部の設定精度をより緩和し、振動等に対す
る信頼性をより向上するという効果を奏する。Also, since the common optical system is a collimating optical system that narrows the light from the light source into parallel light in the measurement area and the reflecting mirror is a plane mirror, the setting accuracy of each part other than the reflecting mirror of the optical dust sensor optical system can be improved. The effect is further mitigated, and the reliability against vibration and the like is further improved.
【００３８】さらに、共用光学系と光学素子に代えて、
上記共用光学系と上記光学素子のそれぞれの機能を有す
る一体化した複合光学系としたので、光学式ほこりセン
サ光学系をコンパクトに構成でき、また、振動等に対す
る信頼性を向上するという効果を奏する。Further, instead of the shared optical system and the optical element,
Since the integrated optical system having the respective functions of the shared optical system and the optical element is integrated, the optical dust sensor optical system can be configured compactly, and the reliability against vibration etc. is improved. .
【００３９】また、光源と光検出器と共用光学系と光学
素子に代えて、検出対象のほこりの大きさに対して前方
散乱を主とするＭｉｅ散乱を発生させる波長の光源とな
るレーザダイオードと、上記レーザダイオードからの光
を測定領域に絞り込む対物レンズと、反射鏡で反射され
て上記対物レンズに入射した上記レーザダイオードから
の光を検出する光検出器となるフォトダイオードとを有
する光ピックアップ光学系を備え、上記対物レンズの後
側焦点位置を測定領域とし、測定領域付近の所定の位置
に反射鏡を設置したので、光学式ほこりセンサ光学系を
コンパクトに構成でき、かつ、量産製品である光ピック
アップ光学系の流用により低価格化できるという効果を
奏する。Further, in place of the light source, the photodetector, the shared optical system and the optical element, a laser diode serving as a light source of a wavelength for generating Mie scattering mainly due to forward scattering with respect to the size of dust to be detected, An optical pickup optical having an objective lens for narrowing the light from the laser diode to a measurement region and a photodiode serving as a photodetector for detecting the light from the laser diode reflected by a reflecting mirror and incident on the objective lens. Since the rear focus position of the objective lens is set as the measurement area and the reflecting mirror is installed at a predetermined position near the measurement area, the optical dust sensor optical system can be configured compactly and is a mass-produced product. By diverting the optical system of the optical pickup, it is possible to reduce the price.
【図１】 本発明による光学式ほこりセンサ光学系の実
施の形態１を示す構成説明図である。FIG. 1 is a configuration explanatory view showing a first embodiment of an optical dust sensor optical system according to the present invention.
【図２】 光源の波長を０．７８μｍとしたときの粒径
１μｍのほこりによる散乱強度の散乱角依存性を示す図
である。FIG. 2 is a diagram showing a scattering angle dependence of a scattering intensity due to dust having a particle diameter of 1 μm when a wavelength of a light source is 0.78 μm.
【図３】 本発明による光学式ほこりセンサ光学系の光
検出器の出力レベル変動例を示す図である。FIG. 3 is a diagram showing an example of output level fluctuations of a photodetector of an optical dust sensor optical system according to the present invention.
【図４】 本発明による光学式ほこりセンサ光学系の実
施の形態２を示す構成説明図である。FIG. 4 is a structural explanatory diagram showing Embodiment 2 of the optical dust sensor optical system according to the present invention.
【図５】 本発明による光学式ほこりセンサ光学系の実
施の形態３を示す構成説明図である。FIG. 5 is a configuration explanatory view showing a third embodiment of the optical dust sensor optical system according to the present invention.
【図６】 本発明による光学式ほこりセンサ光学系の実
施の形態３を示す構成説明図である。FIG. 6 is a structural explanatory view showing a third embodiment of the optical dust sensor optical system according to the present invention.
【図７】 本発明による光学式ほこりセンサ光学系の実
施の形態３を示す構成説明図である。FIG. 7 is a structural explanatory view showing a third embodiment of the optical dust sensor optical system according to the present invention.
【図８】 従来の光学式ほこりセンサ光学系の構成説明
図である。FIG. 8 is a structural explanatory view of a conventional optical dust sensor optical system.
【図９】 従来の光学式ほこりセンサ光学系の光検出器
の出力レベル変動例を示す図である。FIG. 9 is a diagram showing an example of output level fluctuations of a photodetector of a conventional optical dust sensor optical system.
１０ 光源（レーザダイオード）、２０ 照射光学系、
２１ コリメータレンズ、２２ 楕円面鏡、３０ 集光
光学系、４０ 光検出器（フォトダイオード）、５０
測定領域、６０、６１ 共用光学系、７０ 平面鏡、７
１ 球面鏡、８０ 光学素子、９０ ピックアップ光学
系、９１ 結合レンズ、９２ 偏光ビームスプリッタ、
９３ 対物レンズ、９４ 偏光ビームスプリッタ、９５
集光レンズ、１００ 光、１０１ 散乱光、１１０
試料、１２０ セル。10 light source (laser diode), 20 irradiation optical system,
21 collimator lens, 22 ellipsoidal mirror, 30 condensing optical system, 40 photodetector (photodiode), 50
Measurement area, 60, 61 shared optical system, 70 plane mirror, 7
1 spherical mirror, 80 optical element, 90 pickup optical system, 91 coupling lens, 92 polarization beam splitter,
93 Objective Lens, 94 Polarization Beam Splitter, 95
Condensing lens, 100 light, 101 scattered light, 110
Sample, 120 cells.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 安藤 俊行 東京都千代田区丸の内二丁目２番３号 三菱電機株式会社内 (72)発明者 笠原 久美雄 東京都千代田区丸の内二丁目２番３号 三菱電機株式会社内 (72)発明者 片木 孝至 東京都千代田区丸の内二丁目２番３号 三菱電機株式会社内 (56)参考文献 特開 昭52−11079（ＪＰ，Ａ) 特開 平５−12617（ＪＰ，Ａ) 特開 平４−62455（ＪＰ，Ａ) 特開 平１−147347（ＪＰ，Ａ) 特開 平１−256045（ＪＰ，Ａ) 特表 平９−502794（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G01N 15/06 G01N 21/49 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Ando 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (72) Inventor Kumio Kasahara 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Incorporated (72) Inventor Takashi Kataki 2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (56) Reference JP-A-52-11079 (JP, A) JP-A-5-12617 ( JP, A) JP-A-4-62455 (JP, A) JP-A-1-147347 (JP, A) JP-A-1-256045 (JP, A) JP-A-9-502794 (JP, A) (58) ) Fields surveyed (Int.Cl. 7 , DB name) G01N 15/06 G01N 21/49
Claims (8)
散乱を主とするＭｉｅ散乱を発生させる波長の光源と、
上記波長の光を検出する光検出器と、上記光源からの光
が絞り込まれ、上記検出対象のほこりに照射される測定
領域と、上記光源からの光を上記測定領域に絞り込む照
射光学系と、上記測定領域付近の所定の位置に設置さ
れ、上記測定領域に絞り込まれた上記光源からの光を反
射させる反射鏡と、上記反射鏡で反射された光を上記光
検出器に導く集光光学系とを備え、上記検出対象のほこ
りで発生した上記Ｍｉｅ散乱による上記光検出器の出力
の減少により、上記検出対象のほこりを検出することを
特徴とする光学式ほこりセンサ光学系。1. A light source having a wavelength for causing Mie scattering, which is mainly forward scattering, with respect to the size of dust to be detected,
A photodetector that detects light of the wavelength, a light from the light source is narrowed down, a measurement region that is irradiated to dust of the detection target, and an irradiation optical system that narrows the light from the light source into the measurement region, A reflecting mirror installed at a predetermined position in the vicinity of the measurement region and reflecting the light from the light source narrowed down in the measurement region, and a condensing optical system for guiding the light reflected by the reflector to the photodetector. An optical dust sensor optical system comprising: and detecting the dust of the detection target by reducing the output of the photodetector due to the Mie scattering generated in the dust of the detection target.
系において、上記照射光学系と集光光学系に代えて、上
記照射光学系として機能すると共に上記集光光学系とし
ても機能する共通の共用光学系と、上記光源からの光を
上記共用光学系に導くと共に上記反射鏡で反射されて上
記共用光学系に入射した光を上記光検出器に導く、上記
光源から上記共用光学系への光路と上記共用光学系から
上記光検出器への光路を分離する光学素子とを備えたこ
とを特徴とする光学式ほこりセンサ光学系。2. The optical dust sensor optical system according to claim 1, wherein the irradiation optical system and the condensing optical system are replaced by a common one that functions as the irradiation optical system and also as the condensing optical system. The common optical system and the light from the light source are guided to the common optical system, and the light reflected by the reflecting mirror and incident on the common optical system is guided to the photodetector. From the light source to the common optical system. An optical dust sensor optical system comprising an optical path and an optical element for separating the optical path from the shared optical system to the photodetector.
系において、上記共用光学系を上記測定領域に後側焦点
を有し、上記光源からの光を上記測定領域に集光させる
よう形成し、上記反射鏡を上記後側焦点位置に設置され
る平面鏡としたことを特徴とする光学式ほこりセンサ光
学系。3. The optical dust sensor optical system according to claim 2, wherein the shared optical system has a rear focal point in the measurement region and is configured to collect light from the light source in the measurement region. An optical dust sensor optical system characterized in that the reflecting mirror is a plane mirror installed at the rear focal position.
系において、上記共用光学系を上記測定領域に後側焦点
を有し、上記光源からの光を上記測定領域に集光させる
よう形成し、上記反射鏡を上記後側焦点を中心とする球
面内面で形成される球面鏡としたことを特徴とする光学
式ほこりセンサ光学系。4. The optical dust sensor optical system according to claim 2, wherein the shared optical system has a rear focal point in the measurement region and is configured to collect light from the light source in the measurement region. An optical dust sensor optical system characterized in that the reflecting mirror is a spherical mirror formed by an inner surface of a spherical surface centered on the rear focal point.
系において、上記共用光学系を上記光源からの光を平行
光として上記測定領域に絞り込むコリメート光学系と
し、上記反射鏡を平面鏡としたことを特徴とする光学式
ほこりセンサ光学系。5. The optical dust sensor optical system according to claim 2, wherein the common optical system is a collimating optical system that narrows the light from the light source into parallel light to narrow down the measurement area, and the reflecting mirror is a plane mirror. Optical dust sensor optical system characterized by.
学式ほこりセンサ光学系において、上記共用光学系と上
記光学素子に代えて、上記共用光学系と上記光学素子の
それぞれの機能を有する一体化した複合光学系を備えた
ことを特徴とする光学式ほこりセンサ光学系。6. The optical dust sensor optical system according to claim 2, wherein the shared optical system and the optical element have respective functions instead of the shared optical system and the optical element. An optical dust sensor optical system comprising an integrated composite optical system having a.
系において、上記光源と光検出器と共用光学系と光学素
子に代えて、検出対象のほこりの大きさに対して前方散
乱を主とするＭｉｅ散乱を発生させる波長の光源となる
レーザダイオードと、上記レーザダイオードからの光を
上記測定領域に絞り込む対物レンズと、上記反射鏡で反
射されて上記対物レンズに入射した上記レーザダイオー
ドからの光を検出する光検出器となるフォトダイオード
とを有する光ピックアップ光学系を備え、上記対物レン
ズの後側焦点位置を上記測定領域とし、上記反射鏡を上
記対物レンズの後側焦点位置に設置される平面鏡とした
ことを特徴とする光学式ほこりセンサ光学系。7. The optical dust sensor optical system according to claim 2, wherein the light source, the photodetector, the shared optical system, and the optical element are replaced by mainly forward scattering with respect to the size of dust to be detected. Laser diode serving as a light source of a wavelength that causes Mie scattering, an objective lens that narrows the light from the laser diode to the measurement region, and light from the laser diode that is reflected by the reflecting mirror and enters the objective lens. An optical pickup optical system having a photodiode serving as a photodetector for detecting the object, the rear focal position of the objective lens being the measurement region, and the reflecting mirror being installed at the rear focal position of the objective lens. Optical dust sensor optical system characterized by being a plane mirror.
系において、上記光源と光検出器と共用光学系と光学素
子に代えて、検出対象のほこりの大きさに対して前方散
乱を主とするＭｉｅ散乱を発生させる波長の光源となる
レーザダイオードと、上記レーザダイオードからの光を
上記測定領域に絞り込む対物レンズと、上記反射鏡で反
射されて上記対物レンズに入射した上記レーザダイオー
ドからの光を検出する光検出器となるフォトダイオード
とを有する光ピックアップ光学系を備え、上記対物レン
ズの後側焦点位置を上記測定領域とし、上記反射鏡を上
記対物レンズの後側焦点を中心とする球面内面で形成さ
れる球面鏡としたことを特徴とする光学式ほこりセンサ
光学系。8. The optical dust sensor optical system according to claim 2, wherein the light source, the photodetector, the shared optical system, and the optical element are replaced by mainly forward scattering with respect to the size of dust to be detected. Laser diode serving as a light source of a wavelength that causes Mie scattering, an objective lens that narrows the light from the laser diode to the measurement region, and light from the laser diode that is reflected by the reflecting mirror and enters the objective lens. An optical pickup optical system having a photodiode serving as a photodetector for detecting the rear focus of the objective lens as the measurement area, and the reflecting mirror having a spherical surface centered on the rear focus of the objective lens. An optical dust sensor optical system characterized by being a spherical mirror formed by an inner surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31744398A JP3454173B2 (en) | 1998-11-09 | 1998-11-09 | Optical dust sensor optical system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31744398A JP3454173B2 (en) | 1998-11-09 | 1998-11-09 | Optical dust sensor optical system |
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| Publication Number | Publication Date |
|---|---|
| JP2000146819A JP2000146819A (en) | 2000-05-26 |
| JP3454173B2 true JP3454173B2 (en) | 2003-10-06 |
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| KR101710534B1 (en) * | 2014-11-20 | 2017-02-28 | 박정익 | Optical system for sensors with optical method and sensors including the same optical system |
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| JP2000146819A (en) | 2000-05-26 |
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