JPH09288234A - Photographic lens - Google Patents
Photographic lensInfo
- Publication number
- JPH09288234A JPH09288234A JP10011396A JP10011396A JPH09288234A JP H09288234 A JPH09288234 A JP H09288234A JP 10011396 A JP10011396 A JP 10011396A JP 10011396 A JP10011396 A JP 10011396A JP H09288234 A JPH09288234 A JP H09288234A
- Authority
- JP
- Japan
- Prior art keywords
- lens
- lens group
- diaphragm
- negative
- positive
- 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
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Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、レトロフォーカス
型の撮影レンズに関し、特にテレビ電話、監視カメラ、
パソコンテレビ会議用カメラ等に好適な撮影レンズに関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a retrofocus type photographing lens, and more particularly to a videophone, a surveillance camera,
The present invention relates to a photographing lens suitable for a camera for a personal computer video conference.
【0002】[0002]
【従来の技術】テレビ電話や監視カメラ等に用いられる
撮影レンズは、広い画角を有すること、受光素子として
CCDを用いるためテレセン性のよいこと、結像性能が
良いこと、安価でコンパクトなこと等が要求される。2. Description of the Related Art Photographing lenses used for videophones, surveillance cameras, etc. have a wide angle of view, have a good telecentricity because a CCD is used as a light receiving element, have a good imaging performance, and are inexpensive and compact. Etc. are required.
【0003】これらの要求を満たすためには、屈折力の
強い負の第1レンズを有するレトロフォーカス型のレン
ズが好適であり、3枚構成の安価なレンズとして、特開
平7−333499号公報、特開平6−148518号
公報等に記載のレンズが知られている。In order to meet these requirements, a retrofocus type lens having a negative first lens having a strong refractive power is suitable, and an inexpensive lens having a three-lens structure is disclosed in Japanese Patent Laid-Open No. 7-333499. Lenses described in JP-A-6-148518 and the like are known.
【0004】[0004]
【発明が解決しようとする課題】しかしながら上記の如
きレンズは、屈折力の強い負レンズからなる第1レンズ
群と、正レンズと負レンズとからなる第2レンズ群と、
第2レンズ群の近傍に位置した絞りとから構成され、負
の第1レンズによって短波長の像高が小さくなる倍率色
収差が発生するといった問題が避けられない。However, the above-mentioned lens includes the first lens group composed of a negative lens having a strong refractive power, and the second lens group composed of a positive lens and a negative lens.
It is inevitable that a negative first lens, which is composed of a diaphragm located in the vicinity of the second lens group, causes lateral chromatic aberration in which the image height of a short wavelength becomes small.
【0005】本発明は前述の各要求を満たし、特に安価
で倍率色収差も良好なレトロフォーカス型の撮影レンズ
を提案することを課題とする。It is an object of the present invention to propose a retrofocus type photographing lens which satisfies the above-mentioned requirements and is particularly inexpensive and has excellent lateral chromatic aberration.
【0006】[0006]
【課題を解決するための手段】上記課題は、物体側から
順に、1枚の負レンズからなる第1レンズ群と、1枚の
正レンズと1枚の負レンズとからなる正レンズの第2レ
ンズ群と、少なくとも軸外光束の一部を制限する絞りと
から構成され、下記の条件式を満たすことを特徴とする
撮影レンズにより、解決される。SUMMARY OF THE INVENTION The above-mentioned problem is solved by the second lens element of the first lens group consisting of one negative lens element, one positive lens element and one negative lens element in order from the object side. This is solved by a photographing lens that includes a lens group and a diaphragm that limits at least a part of off-axis light flux, and that satisfies the following conditional expression.
【0007】 50≦ν2≦150 但し、ν2は、第2レンズ群の正レンズのパワーをψ2
P、アッベ数をν2Pとし、第2レンズ群の負レンズの
パワーをψ2N、アッベ数をν2Nとしたとき、 (ψ2P+ψ2N)/ν2=(ψ2P/ν2P)+(ψ
2N/ν2N) を満たす値である。50 ≦ ν2 ≦ 150 where ν2 is the power of the positive lens of the second lens group ψ2
P, Abbe number is ν2P, the negative lens power of the second lens group is ψ2N, and Abbe number is ν2N, then (ψ2P + ψ2N) / ν2 = (ψ2P / ν2P) + (ψ
2N / ν2N).
【0008】本願発明は第2レンズ群の像側に、少なく
とも軸外光束の一部を制限する絞りを設けることによっ
て、負の屈折力の第1レンズ群で生じる倍率色収差を、
正の屈折力で適切な正の範囲の等価ν値を有する第2レ
ンズ群によって軽減させている。無論、この絞りは軸外
光束だけでなく、軸上光束を制限する所謂後置絞りであ
ってもよい。According to the invention of the present application, a chromatic aberration of magnification caused in the first lens group having a negative refractive power is provided by providing a diaphragm for limiting at least a part of off-axis light flux on the image side of the second lens group.
It is reduced by the second lens group having a positive refractive power and an equivalent ν value in an appropriate positive range. Of course, this diaphragm may be a so-called post diaphragm that restricts not only the off-axis light beam but also the on-axis light beam.
【0009】条件式は第2レンズ群の等価ν値に関す
る条件式であり、条件式の下限を外れると、軸上色収
差が大きくアンダーになる。上限を外れると、上述の倍
率色収差に関する効果が小さい。The conditional expression is a conditional expression relating to the equivalent ν value of the second lens group. If the lower limit of the conditional expression is not satisfied, the axial chromatic aberration will be largely under. If the upper limit is deviated, the effect on the lateral chromatic aberration is small.
【0010】なお、下記の条件式を満たすと、更に大
きな効果が得られる。Further, if the following conditional expression is satisfied, a greater effect can be obtained.
【0011】 60≦ν2≦90 また、絞りは開口径が不変であり、下記の条件式を満た
すことが望ましい。60 ≦ ν2 ≦ 90 The aperture diameter of the diaphragm is invariable, and it is desirable that the following conditional expression is satisfied.
【0012】 1.0≦rs/hs≦1.3 1.0≦d/f≦3.0 但し、rs:絞りの開口半径 hs:絞りにおける軸上光束の半径 d :第1レンズ群と第2レンズ群との軸上間隔 f :全系の焦点距離 条件式は、絞りの開口径が不変である場合に、適切な
開口半径を定める望ましい条件式であって、下限は自明
であり、上限を外れると上述の倍率色収差に関する効果
が小さい。1.0 ≦ rs / hs ≦ 1.3 1.0 ≦ d / f ≦ 3.0 where rs: aperture radius of diaphragm hs: radius of axial light flux at diaphragm d: first lens group and first lens group On-axis distance between two lens groups f: focal length of the entire system The conditional expression is a desirable conditional expression that determines an appropriate aperture radius when the aperture diameter of the diaphragm is unchanged, and the lower limit is obvious and the upper limit is If it is out of the range, the effect on the chromatic aberration of magnification is small.
【0013】なお、この値が1以外の場合は、この絞り
より前方にFナンバーを定める絞りを別途必要とする。If this value is other than 1, a separate diaphragm for determining the F number is required in front of this diaphragm.
【0014】条件式は、第1レンズ群と第2レンズ群
との望ましい間隔を定めるもので、下限を外れると、第
1レンズ群の屈折力が強くなってディストーションが劣
化するか、或いはバックフォーカスが短くなって、テレ
セン性が劣化する。また、上限を外れると、コンパクト
性が損なわれる。The conditional expression defines a desirable distance between the first lens group and the second lens group. If the lower limit is not satisfied, the refracting power of the first lens group becomes strong and the distortion is deteriorated, or the back focus is reduced. Becomes shorter and the telecentricity deteriorates. Also, if the upper limit is exceeded, compactness is impaired.
【0015】なお、下記の条件式を満たすと、更に大
きな効果が得られる。Further, if the following conditional expression is satisfied, a greater effect can be obtained.
【0016】 1.4≦d/f≦2.5 1.4 ≦ d / f ≦ 2.5
【0017】[0017]
【実施例】以下に、本発明における撮影レンズに関する
4種の実施例を説明する。EXAMPLES The following will describe four examples of photographing lenses according to the present invention.
【0018】なお、各実施例における符号の意味は下記
の通りである。The meanings of the reference numerals in each embodiment are as follows.
【0019】f:焦点距離 F:Fナンバー ω:半画角 r:曲率半径 d:面間距離 n:d線に対する屈折率 ν:d線に対するアッベ数 また、レンズデータの表において、「*」で示したレン
ズ面は非球面であり、光軸方向をx軸、光軸と直交する
方向をy軸、K,Ai,Piを非球面係数とすると、下
記の式で表せる。F: Focal length F: F number ω: Half angle of view r: Radius of curvature d: Distance between surfaces n: Refractive index for d line ν: Abbe number for d line Further, in the lens data table, "*" The lens surface shown by is an aspherical surface, where the optical axis direction is the x axis, the direction orthogonal to the optical axis is the y axis, and K, Ai, and Pi are the aspherical surface coefficients, which can be expressed by the following equation.
【0020】[0020]
【数1】 [Equation 1]
【0021】また、レンズ断面図において、G1は第1
レンズ群、G2は第2レンズ群、1は絞り、2はフィル
ター、3はカバーガラスである。In the sectional view of the lens, G1 is the first
A lens group, G2 is a second lens group, 1 is a diaphragm, 2 is a filter, and 3 is a cover glass.
【0022】〔実施例1〕 f=4.11, F=2.8, 2ω=61.4° レンズデータを表1に示す。Example 1 f = 4.11, F = 2.8, 2ω = 61.4 ° Lens data are shown in Table 1.
【0023】[0023]
【表1】 [Table 1]
【0024】但し、絞りは第5面の像側0.50の位置
にある。However, the diaphragm is located 0.50 on the image side of the fifth surface.
【0025】非球面係数を表2に示す。Table 2 shows the aspherical surface coefficients.
【0026】[0026]
【表2】 [Table 2]
【0027】更に、レンズ断面図を図1に、収差図を図
2に示す。Further, a sectional view of the lens is shown in FIG. 1, and an aberration diagram is shown in FIG.
【0028】〔実施例2〕 f=4.04, F=2.8, 2ω=61.8° レンズデータを表3に示す。Example 2 f = 4.04, F = 2.8, 2ω = 61.8 ° Table 3 shows lens data.
【0029】[0029]
【表3】 [Table 3]
【0030】但し、絞りは第5面の像側0.50の位置
にある。However, the diaphragm is located 0.50 on the image side of the fifth surface.
【0031】非球面係数を表4に示す。Table 4 shows the aspherical surface coefficients.
【0032】[0032]
【表4】 [Table 4]
【0033】更に、レンズ断面図を図3に、収差図を図
4に示す。Further, a sectional view of the lens is shown in FIG. 3, and an aberration diagram is shown in FIG.
【0034】〔実施例3〕 f=4.10, F=2.8, 2ω=62.0° レンズデータを表5に示す。Example 3 f = 4.10, F = 2.8, 2ω = 62.0 ° Lens data are shown in Table 5.
【0035】[0035]
【表5】 [Table 5]
【0036】但し、絞りは第6面の像側0.20の位置
にある。However, the stop is at the position of 0.20 on the image side of the sixth surface.
【0037】非球面係数を表6に示す。Table 6 shows the aspherical surface coefficients.
【0038】[0038]
【表6】 [Table 6]
【0039】更に、レンズ断面図を図5に、収差図を図
6に示す。Further, a sectional view of the lens is shown in FIG. 5, and an aberration diagram is shown in FIG.
【0040】〔実施例4〕 f=4.09, F=2.8, 2ω=61.2° レンズデータを表7に示す。Example 4 f = 4.09, F = 2.8, 2ω = 61.2 ° Lens data are shown in Table 7.
【0041】[0041]
【表7】 [Table 7]
【0042】但し、絞りは第5面の像側0.50の位置
にある。However, the diaphragm is located at a position of 0.50 on the image side of the fifth surface.
【0043】非球面係数を表8に示す。Table 8 shows the aspherical coefficients.
【0044】[0044]
【表8】 [Table 8]
【0045】更に、レンズ断面図を図7に、収差図を図
8に示す。Further, a sectional view of the lens is shown in FIG. 7, and an aberration diagram is shown in FIG.
【0046】なお、以上の各実施例において、条件式
〜に対応する値は下記の表9の如くである。In each of the above embodiments, the values corresponding to the conditional expressions 1 to 5 are as shown in Table 9 below.
【0047】[0047]
【表9】 [Table 9]
【0048】[0048]
【発明の効果】請求項1〜3によれば、倍率色収差を始
めとする結像性能が優れ、コンパクトで、テレビ電話や
監視カメラに好適なレトロフォーカス型の撮影レンズを
得ることができる。According to the first to third aspects of the present invention, it is possible to obtain a retrofocus type taking lens which is excellent in image forming performance such as lateral chromatic aberration, compact, and suitable for videophones and surveillance cameras.
【図1】実施例1のレンズ断面図である。FIG. 1 is a sectional view of a lens according to a first embodiment.
【図2】実施例1の収差図である。FIG. 2 is an aberration diagram of the first embodiment.
【図3】実施例2のレンズ断面図である。FIG. 3 is a sectional view of a lens according to a second embodiment.
【図4】実施例2の収差図である。FIG. 4 is an aberration diagram of the second embodiment.
【図5】実施例3のレンズ断面図である。FIG. 5 is a sectional view of a lens according to a third embodiment.
【図6】実施例3の収差図である。FIG. 6 is an aberration diagram for Example 3.
【図7】実施例4のレンズ断面図である。FIG. 7 is a lens cross-sectional view of Example 4.
【図8】実施例4の収差図である。FIG. 8 is an aberration diagram for Example 4.
G1 第1レンズ群 G2 第2レンズ群 1 絞り 2 フィルター 3 カバーガラス G1 First lens group G2 Second lens group 1 Aperture 2 Filter 3 Cover glass
Claims (3)
る第1レンズ群と、1枚の正レンズと1枚の負レンズと
からなる正レンズの第2レンズ群と、少なくとも軸外光
束の一部を制限する絞りとから構成され、下記の条件式
を満たすことを特徴とする撮影レンズ。 50≦ν2≦150 但し、ν2は、第2レンズ群の正レンズのパワーをψ2
P、アッベ数をν2Pとし、第2レンズ群の負レンズの
パワーをψ2N、アッベ数をν2Nとしたとき、 (ψ2P+ψ2N)/ν2=(ψ2P/ν2P)+(ψ
2N/ν2N) を満たす値である。1. A first lens group consisting of one negative lens in order from the object side, a second lens group of positive lens consisting of one positive lens and one negative lens, and at least an off-axis light beam. And a diaphragm that restricts a part of the above, and satisfies the following conditional expression. 50 ≦ ν2 ≦ 150 where ν2 is the power of the positive lens of the second lens group ψ2
If P and Abbe number are ν2P, the power of the negative lens of the second lens group is ψ2N, and Abbe number is ν2N, then (ψ2P + ψ2N) / ν2 = (ψ2P / ν2P) + (ψ
2N / ν2N).
合成樹脂から形成されていることを特徴とする請求項1
に記載の撮影レンズ。2. The first lens group and the second lens group are made of synthetic resin.
Shooting lens described in.
条件式を満たすことを特徴とする請求項1又は請求項2
に記載の撮影レンズ。 1.0≦rs/hs≦1.3 1.0≦d/f≦3.0 但し、rs:絞りの開口半径 hs:絞りにおける軸上光束の半径 d :第1レンズ群と第2レンズ群との軸上間隔 f :全系の焦点距離3. The diaphragm according to claim 1, wherein an aperture diameter of the diaphragm is invariable and the following conditional expression is satisfied.
Shooting lens described in. 1.0 ≦ rs / hs ≦ 1.3 1.0 ≦ d / f ≦ 3.0 where rs: aperture radius of diaphragm hs: radius of axial light flux at diaphragm d: first lens group and second lens group On-axis distance f: focal length of the entire system
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP10011396A JPH09288234A (en) | 1996-04-22 | 1996-04-22 | Photographic lens |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP10011396A JPH09288234A (en) | 1996-04-22 | 1996-04-22 | Photographic lens |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH09288234A true JPH09288234A (en) | 1997-11-04 |
Family
ID=14265322
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP10011396A Pending JPH09288234A (en) | 1996-04-22 | 1996-04-22 | Photographic lens |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH09288234A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2001159732A (en) * | 1999-12-02 | 2001-06-12 | Nikon Corp | Super wide angle lens and photographic device having the lens |
JP2011253006A (en) * | 2010-06-01 | 2011-12-15 | Fujifilm Corp | Infrared imaging lens and imaging apparatus |
US10222583B2 (en) | 2016-10-21 | 2019-03-05 | Largan Precision Co., Ltd. | Micro imaging system, imaging apparatus and electronic device |
-
1996
- 1996-04-22 JP JP10011396A patent/JPH09288234A/en active Pending
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2001159732A (en) * | 1999-12-02 | 2001-06-12 | Nikon Corp | Super wide angle lens and photographic device having the lens |
JP2011253006A (en) * | 2010-06-01 | 2011-12-15 | Fujifilm Corp | Infrared imaging lens and imaging apparatus |
US10222583B2 (en) | 2016-10-21 | 2019-03-05 | Largan Precision Co., Ltd. | Micro imaging system, imaging apparatus and electronic device |
US10571655B2 (en) | 2016-10-21 | 2020-02-25 | Largan Precision Co., Ltd. | Micro imaging system, imaging apparatus and electronic device |
US11249281B2 (en) | 2016-10-21 | 2022-02-15 | Largan Precision Co., Ltd. | Micro imaging system, imaging apparatus and electronic device |
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