JP3367545B2 - Optical spectrum detector - Google Patents

Optical spectrum detector

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Publication number
JP3367545B2
JP3367545B2 JP26913795A JP26913795A JP3367545B2 JP 3367545 B2 JP3367545 B2 JP 3367545B2 JP 26913795 A JP26913795 A JP 26913795A JP 26913795 A JP26913795 A JP 26913795A JP 3367545 B2 JP3367545 B2 JP 3367545B2
Authority
JP
Japan
Prior art keywords
diffraction grating
optical system
lens
condensing optical
wavelength
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
Application number
JP26913795A
Other languages
Japanese (ja)
Other versions
JPH0989668A (en
Inventor
敏之 浪川
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nikon Corp
Original Assignee
Nikon Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nikon Corp filed Critical Nikon Corp
Priority to JP26913795A priority Critical patent/JP3367545B2/en
Publication of JPH0989668A publication Critical patent/JPH0989668A/en
Application granted granted Critical
Publication of JP3367545B2 publication Critical patent/JP3367545B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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  • Spectrometry And Color Measurement (AREA)

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、広範囲の波長を同
時に観察する光スペクトル検出装置に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical spectrum detector for simultaneously observing a wide range of wavelengths.

【0002】[0002]

【発明が解決しようとする課題】光スペクトル検出装置
は、回折格子でスペクトル分光を行い、この分光された
光束をCCD等の光電変換素子から成る光検出器の検出
平面上に集光させて、スペクトル分析を行っている。分
光された光を検出平面に集光する集光光学系としては、
従来より、一般的なf・tanθレンズが用いられてい
た。しかるに回折格子によるスペクトル分散は非線形性
を持っており、f・tanθレンズではこの非線形性を
相殺することができない。したがって検出平面での各波
長のスペクトルの結像は、各波長間の波長差に比例しな
い非線形な間隔で形成され、この結果CCDのピッチに
合わずに検出効率の低下を招き、あるいはこれを解消す
るために、CCDのピッチの変更などの負担を招いてい
た。したがって本発明は、検出平面での各波長間の像の
位置が、各波長間の波長差に比例する光スペクトル検出
装置を提供することを課題とする。
An optical spectrum detecting device performs spectral spectroscopy with a diffraction grating, collects the dispersed light flux on a detection plane of a photodetector composed of a photoelectric conversion element such as CCD, and We are doing spectrum analysis. As a condensing optical system that condenses the dispersed light on the detection plane,
Conventionally, a general f · tan θ lens has been used. However, the spectral dispersion due to the diffraction grating has nonlinearity, and the f · tan θ lens cannot cancel this nonlinearity. Therefore, the image formation of the spectrum of each wavelength on the detection plane is formed at a non-linear interval that is not proportional to the wavelength difference between each wavelength, and as a result, it does not match the pitch of the CCD and causes a decrease in detection efficiency, or eliminates this. Therefore, the burden of changing the pitch of the CCD is incurred. Therefore, it is an object of the present invention to provide an optical spectrum detection device in which the position of an image between wavelengths on a detection plane is proportional to the wavelength difference between wavelengths.

【0003】[0003]

【課題を解決するための手段】本発明は、回折格子の法
線と集光光学系の光軸とを平行に配置し、且つ集光光学
系をf・sinθレンズによって構成することにより、
上記課題を解決したものである。この構成により、回折
格子の分光によるスペクトル分散の非線形性はf・si
nθレンズによって相殺され、検出平面上で線形なスペ
クトル分布が得られる。
According to the present invention, the normal line of the diffraction grating and the optical axis of the condensing optical system are arranged in parallel, and the condensing optical system is constituted by an f · sin θ lens.
This is a solution to the above problem. With this configuration, the nonlinearity of the spectral dispersion due to the spectrum of the diffraction grating is f · si.
It is canceled by the nθ lens, resulting in a linear spectral distribution on the detection plane.

【0004】[0004]

【発明の実施の形態】本発明の実施の形態を図面によっ
て説明する。図1は本発明の一実施例の概略光学系を示
し、回折格子1に入射する白色平行光は、回折格子1に
よって分光された後、集光レンズ2によって光検出器3
の検出平面3a上に結像している。回折格子1の法線N
は集光レンズ2の光軸zと平行に配置されており、また
集光レンズ2としてはf・sinθレンズが用いられて
いる。したがって入射角θで入射したスペクトルの像高
yは、fを集光レンズの焦点距離として、 y=f・sinθ ‥‥(1) で与えられる。
BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic optical system according to an embodiment of the present invention. White parallel light incident on a diffraction grating 1 is split by the diffraction grating 1 and then a photodetector 3 by a condenser lens 2.
An image is formed on the detection plane 3a. Normal line N of diffraction grating 1
Are arranged parallel to the optical axis z of the condenser lens 2, and as the condenser lens 2, an f · sin θ lens is used. Therefore, the image height y of the spectrum incident at the incident angle θ is given by y = f · sin θ (1) where f is the focal length of the condenser lens.

【0005】他方、回折格子による回折角は、αを入射
角、βを射出角、Nを単位長さ当たりの格子数、mを回
折の次数、λを波長とすると、 sinβ=sinα+Nmλ ‥‥(2) で与えられる。また本実施例では、回折格子1の法線N
が集光レンズ2の光軸zと平行に配置されているから、 θ=β ‥‥(3) となっている。
On the other hand, the diffraction angle of the diffraction grating is: sin β = sin α + Nmλ (where α is the incident angle, β is the exit angle, N is the number of gratings per unit length, m is the diffraction order, and λ is the wavelength). 2) is given in. In this embodiment, the normal line N of the diffraction grating 1
Is arranged parallel to the optical axis z of the condenser lens 2, so that θ = β (3).

【0006】したがって、(1)、(2)及び(3)式
より、 y=f・(sinα+Nmλ) となる。故に、基準波長に対する波長の差をΔλとし、
基準波長との間の像高の差をΔyとすると、 Δy=fNm・Δλ となり、像高差Δyは波長差Δλに比例することとな
る。
Therefore, from equations (1), (2) and (3), y = f · (sin α + Nmλ). Therefore, the difference between the wavelength and the reference wavelength is Δλ,
If the difference in image height from the reference wavelength is Δy, then Δy = fNmΔλ, and the image height difference Δy is proportional to the wavelength difference Δλ.

【0007】より一般的に説明すると、 dy/dλ=(dy/dθ)・(dθ/dβ)・(dβ/dλ) ‥‥(4) において、回折格子1の法線Nと集光レンズ2の光軸z
とが平行でない一般的な場合には、aを法線Nと光軸z
とのなす角度として、 θ=β+a であるから、(4)式の右辺第2項は、 dθ/dβ=1 となる。また(4)式の右辺第3項は、(2)式より、 dβ/dλ=Nm/cosβ であるから、結局(4)式は、 dy/dλ=(dy/dθ)・Nm/cosβ ‥‥(5) となる。
More generally, dy / dλ = (dy / dθ)  (dθ / dβ)  (dβ / dλ) (4), the normal line N of the diffraction grating 1 and the condenser lens 2 Optical axis z
In the general case where and are not parallel, let a be the normal line N and the optical axis z.
Since θ = β + a as the angle formed by and, the second term on the right side of the equation (4) is dθ / dβ = 1. Further, since the third term on the right side of the equation (4) is dβ / dλ = Nm / cosβ from the equation (2), the equation (4) is ultimately dy / dλ = (dy / dθ) · Nm / cosβ. It becomes (5).

【0008】従来技術のように集光レンズ2としてf・
tanθレンズを用いると、 y=f・tanθ であるから、(5)式は、 dy/dλ=fNm/cos2θ/cosβ となり、dy/dλ=const.とすることができな
い。したがって回折格子1と集光レンズ2とをいかよう
な関係にて配置しようとも、すなわち、例えばθ=βと
なるように配置しようとも、波長λに対して像高yを線
形に変化させることができない。
As in the prior art, f.
When a tan θ lens is used, y = f · tan θ. Therefore, the expression (5) becomes dy / dλ = fNm / cos 2 θ / cos β, and dy / dλ = const. And can't. Therefore, no matter how the diffraction grating 1 and the condenser lens 2 are arranged, that is, θ = β, for example, the image height y can be linearly changed with respect to the wavelength λ. Can not.

【0009】しかるに本実施例では、集光レンズ2とし
てf・sinθレンズを用いているから、(5)式は、 dy/dλ=fNm・cosθ/cosβ となり、更に、θ=βとなるように配置しているから、 dy/dλ=const. となる。こうして像高yが波長λに対して線形に変化す
ることとなる。
In the present embodiment, however, since the f.sin.theta. Lens is used as the condenser lens 2, the equation (5) becomes dy / d.lambda. = FNm.cos.theta. / Cos.beta., And .theta. =. Beta. Since it is arranged, dy / dλ = const. Becomes In this way, the image height y changes linearly with respect to the wavelength λ.

【0010】なおf・sinθレンズは負の歪曲収差を
持っている。したがって厳密にはf・sinθの特性は
持っていなくとも、負の歪曲収差を持つレンズ系を集光
レンズ2として用いることもできる。この場合には、像
高yと波長λとの間の線形性が若干劣ることとなるが、
それでも従来技術よりは優れた効果を得ることができ
る。また図1では回折格子として反射型のものを図示し
ているが、透過型の回折格子を用いることもできる。
The f · sin θ lens has negative distortion. Therefore, it is possible to use a lens system having negative distortion aberration as the condenser lens 2 even if it does not have the characteristic of f · sin θ strictly. In this case, the linearity between the image height y and the wavelength λ is slightly inferior,
Even so, it is possible to obtain an effect superior to that of the conventional technique. Further, although a reflection type diffraction grating is shown in FIG. 1, a transmission type diffraction grating may be used.

【0011】[0011]

【発明の効果】上述の如く本発明によれば、分光された
スペクトルが、その波長に応じて光検出器の検出平面上
に線形に分布するため、検出器の利用効率が高まり、ま
た検出器の制作も容易になるという利点がある。
As described above, according to the present invention, the separated spectrum is linearly distributed on the detection plane of the photodetector according to its wavelength, so that the utilization efficiency of the detector is increased and the detector is also used. There is an advantage that the production of is easy.

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

【図1】本発明の一実施例を示す概略構成図FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

【符号の説明】[Explanation of symbols]

1…回折格子 2…集光レンズ 3…光検出器 3a…検出平面 N…法線 z…光軸 1 ... Diffraction grating 2 ... Condenser lens 3 ... Photodetector 3a ... Detection plane N ... normal z ... optical axis

───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7,DB名) G01J 3/00 - 3/52 G01N 21/00 - 21/61 JICSTファイル(JOIS)─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields investigated (Int.Cl. 7 , DB name) G01J 3/00-3/52 G01N 21/00-21/61 JISST file (JOIS)

Claims (2)

(57)【特許請求の範囲】(57) [Claims] 【請求項1】回折格子によって分光した光を集光光学系
によって光検出器の検出平面上に集光した光スペクトル
検出装置において、 前記回折格子の法線と前記集光光学系の光軸とを平行に
配置し、且つ前記集光光学系をf・sinθレンズによ
って構成したことを特徴とする光スペクトル検出装置。
1. An optical spectrum detection device in which light dispersed by a diffraction grating is condensed on a detection plane of a photodetector by a condensing optical system, the normal line of the diffraction grating and an optical axis of the condensing optical system. Are arranged in parallel, and the condensing optical system is constituted by an f · sin θ lens.
【請求項2】回折格子によって分光した光を集光光学系
によって光検出器の検出平面上に集光した光スペクトル
検出装置において、 前記回折格子の法線と前記集光光学系の光軸とを平行に
配置し、且つ前記集光光学系を負の歪曲収差を有するレ
ンズ系によって構成したことを特徴とする光スペクトル
検出装置。
2. An optical spectrum detecting device in which light condensed by a diffraction grating is condensed on a detection plane of a photodetector by a condensing optical system, the normal line of the diffraction grating and an optical axis of the condensing optical system. Are arranged in parallel, and the condensing optical system is constituted by a lens system having a negative distortion aberration.
JP26913795A 1995-09-22 1995-09-22 Optical spectrum detector Expired - Fee Related JP3367545B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP26913795A JP3367545B2 (en) 1995-09-22 1995-09-22 Optical spectrum detector

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP26913795A JP3367545B2 (en) 1995-09-22 1995-09-22 Optical spectrum detector

Publications (2)

Publication Number Publication Date
JPH0989668A JPH0989668A (en) 1997-04-04
JP3367545B2 true JP3367545B2 (en) 2003-01-14

Family

ID=17468211

Family Applications (1)

Application Number Title Priority Date Filing Date
JP26913795A Expired - Fee Related JP3367545B2 (en) 1995-09-22 1995-09-22 Optical spectrum detector

Country Status (1)

Country Link
JP (1) JP3367545B2 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3346374B2 (en) * 1999-06-23 2002-11-18 住友電気工業株式会社 Laser drilling machine
US6650413B2 (en) 1999-08-08 2003-11-18 Institut National D'optique Linear spectrometer
CA2280531C (en) * 1999-08-19 2008-06-10 Simon Thibault F-sin (.theta.) lens system and method of use of same
US6597831B2 (en) 2000-11-29 2003-07-22 Institut National D'optique Linear wavelength DWDM
JP5775687B2 (en) 2010-12-17 2015-09-09 オリンパス株式会社 Spectroscopic detector

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5670431A (en) * 1979-11-15 1981-06-12 Ricoh Co Ltd Photometer
JPH0560600A (en) * 1991-09-03 1993-03-09 Nikon Corp Infrared optical system
JPH05281040A (en) * 1992-03-31 1993-10-29 Matsushita Electric Ind Co Ltd Spectrum measuring device
JPH05340815A (en) * 1992-06-12 1993-12-24 Fujitsu Ltd Multichannel spectrophotometer
GB9410395D0 (en) * 1994-05-24 1994-07-13 Renishaw Plc Spectroscopic apparatus

Also Published As

Publication number Publication date
JPH0989668A (en) 1997-04-04

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