JPH04238312A - Subminiature extremely wide-angle lens - Google Patents
Subminiature extremely wide-angle lensInfo
- Publication number
- JPH04238312A JPH04238312A JP3021678A JP2167891A JPH04238312A JP H04238312 A JPH04238312 A JP H04238312A JP 3021678 A JP3021678 A JP 3021678A JP 2167891 A JP2167891 A JP 2167891A JP H04238312 A JPH04238312 A JP H04238312A
- Authority
- JP
- Japan
- Prior art keywords
- lens
- object side
- focal length
- lenses
- convex
- 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.)
- Granted
Links
- 230000005499 meniscus Effects 0.000 claims abstract description 8
- 230000004075 alteration Effects 0.000 abstract description 20
- 239000002131 composite material Substances 0.000 abstract 3
- 201000009310 astigmatism Diseases 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 206010010071 Coma Diseases 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
Landscapes
- Lenses (AREA)
Abstract
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は，車載用カメラ，監視用
カメラ等に使用される大きな歪曲収差を有する超小型超
広角レンズに関する。
【０００２】
【従来の技術】一般に車載用カメラや監視用カメラ等に
使用されるレンズは，広範な視野をカバーする為に大き
な画角を持つ一方で，カメラ全体の小型軽量化を図るた
めに軽量コンパクトであることとが望まれいる。
【０００３】しかしながら，従来の超広角レンズは，一
般的に７枚乃至１０枚以上とレンズ構成枚数の多い構造
のものがほとんである。
【０００４】
【発明が解決しようとする課題】そのため，従来の超広
角レンズは，コストが高く，又，レンズ枚数が多いため
に全長が長くなってしまい，カメラの超小型化には適さ
ないという問題点があった。
【０００５】
【課題を解決するための手段】本発明はこの様な問題点
に鑑みてなされたものであり，レンズ全長が合成焦点距
離の３倍程度と非常に短く，又，４群４枚構成という従
来レンズの約半分の極めてシンプルなレンズ構成枚数で
ありながら，１０２°の広画角及びＦ２．１の十分な明
るさを持ち，しかも，前玉径が小さく，諸収差が良好に
補正された超小型の超広角レンズを得ることを目的とす
るものである。
【０００６】要約すれば，本発明の超小型超広角レンズ
は，物体側から順番に，前記物体側に凸面を向けた凹メ
ニスカスレンズの第１レンズ，前記物体側に凸面を向け
た凹メニスカスレンズの第２レンズ，凸レンズの第３レ
ンズ，凸レンズの第４レンズからなり，正負のレンズに
少なくとも１面の非球面を有し，次の数１〜数４に規定
する条件を満足することを特徴とする。
【数１】ｆ＜｜ｆ１，２ ｜＜２ｆ
【数２】｜ｆ１ ｜＜｜ｆ２ ｜
【数３】ν１ ＜ν２ ，ν３ ＞ν４ 【数４】ｆ＜
ｄ２ ＜１．３ｆ
但し，
ｆ ：全系の合成焦点距離
ｆｉ ：第ｉレンズの焦点距離ｆ１，２
：第１，２レンズの合成焦点距離νｉ ：第ｉ
レンズのアッベ数ｄ２ ：第１レンズと第２レ
ンズの空気間隔とする。
【０００７】
【作用】先ず，本発明の超小型超広角レンズは，凹レン
ズの第１レンズの像面側の面を非球面にすることにより
，第１，第２レンズの間隔を短くしつつ，ここで発生す
る収差を補正するものである。
【０００８】又，本発明の超小型超広角レンズは，凸レ
ンズの第４レンズを非球面とすることにより，従来２〜
３枚のレンズで補正していた球面収差，非点収差，コマ
収差等を１枚のレンズで補正している。
【０００９】数１の条件は前群発散系を構成するための
条件であり，非点収差，コマ収差及び全系の小型化に関
連する条件である。｜ｆ１，２ ｜が２ｆを越えると，
バックフォーカスが短くなる。又，非点収差の補正が困
難になり，この非点収差を補正するために，第２，第３
レンズの間隔を広げなければならなくなる。しかしなが
ら，その様にした場合には，レンズ全長が長くなってし
まい，凹レンズの第１レンズの像面側を非球面にした意
味が失われ，又，本発明の目的の超小型化が達成できな
くなる。又，｜ｆ１，２ ｜がｆよりも短いと，発散系
で発生するコマ収差が著しく大きくなってしまい，たと
え，非球面レンズを用いても収差補正が困難になる。
【００１０】又，数２の条件も前群発散系を構成するた
めの条件である。この条件が満たされないと前玉径が大
きくなり，超小型化という発明の目的が達成できなくな
るとともに，収差補正も困難になる。
【００１１】又，数３の条件は倍率の色収差の補正に関
連する条件である。この条件が満たされないと，倍率の
色収差が大きくなり，補正が困難になる。
【００１２】更に，数４の条件はレンズ全長に関連する
条件である。ｄ２ が１．３ｆよりも大きくなると収差
補正に関しては有利になるが，レンズ全長が長くなり，
前玉径も大きくなるため，本発明の目的の超小型化が達
成できなくなる。又，ｄ２ がｆよりも短いと歪曲収差
の補正が困難となるし，第１レンズの像面側の面の曲率
半径が非常に小さくなり，レンズ加工も困難になる。
【００１３】
【実施例】以下，図面を参照して本発明の実施例を説明
する。図１の光軸断面図に示す様に本発明の超小型超広
角レンズは，物体側から順番に，前記物体側に凸面を向
けた凹メニスカスレンズの第１レンズ，前記物体側に凸
面を向けた凹メニスカスレンズの第２レンズ，凸レンズ
の第３レンズ，凸レンズの第４レンズからなり，上述の
数１〜数４に規定する条件を満足する。又，第１図の実
施例では，ｒ２ 面とｒ８ 面に非球面を有し，その非
球面形状は数５によって規定される。
【００１４】
【数５】
但し，数５において，Ｚ：光軸からの高さがｙ
の非球面上の点の非球面頂点の接平面からの距離。
ｙ：光軸からの高さ。
Ｃ：非球面頂点の曲率（＝１／ｒ）。
ε：円錐定数。
Ｄ，Ｅ，Ｆ，Ｇ：非球面係数。
を表すものとする。
【００１５】次に，上記実施例の具体的な数値を表１に
示す。尚，表中において，ｒ１ 〜ｒ８ は物体側から
順次レンズ各面の曲率半径を，ｄ１ 〜ｄ７ は物体側
から順次各レンズの肉圧又はレンズ各面間の空気間隔を
，ｎ１ 〜ｎ４ は物体側から順次各レンズの屈折率を
，ν１ 〜ν４ は物体側から順次各レンズのアッベ数
を各々示す。
【００１６】又，図２は上記実施例の球面収差，図３は
上記実施例の非点収差，図４は上記実施例の歪曲収差，
図５は上記実施例の色収差を各々示す。又，これらの特
性曲線において，ｄはｄ線，ＦはＦ線，ＣはＣ線を各々
示し，ＳＣはサインコンデションを示す。更に，図３に
おいて，Ｓはサジタル方向，Ｍはメリディオナル方向を
各々示す。
【００１７】
【表１】
【００１８】
【発明の効果】本発明によれば，上記実施例及び収差曲
線に見られる様に，レンズ全長が焦点距離の３倍程度と
非常に短く，又，従来レンズの約半分のレンズ構成枚数
である４群４枚構成という非常にシンプルで少ないレン
ズ構成枚数でありながら，画角１０２°の広範な範囲を
包括し，Ｆナンバも２．１と十分な明るさを持ち，前玉
径も小さく，しかも諸収差が良好に補正された超小型超
広角レンズを得ることができるものであり，車載用カメ
ラや監視用カメラのためのレンズとして好適なる特性を
得ることができる。
【００１９】Description: FIELD OF INDUSTRIAL APPLICATION The present invention relates to an ultra-compact, ultra-wide-angle lens having large distortion and used in vehicle-mounted cameras, surveillance cameras, and the like. [0002] Generally, lenses used for vehicle-mounted cameras, surveillance cameras, etc. have a large angle of view to cover a wide field of view, but in order to make the entire camera smaller and lighter, It is desired that the device be lightweight and compact. However, most conventional ultra-wide-angle lenses have a structure with a large number of lenses, generally 7 to 10 or more lenses. [0004] Problems to be Solved by the Invention [0004] Therefore, conventional ultra-wide-angle lenses are expensive and have a large total length due to the large number of lenses, making them unsuitable for miniaturizing cameras. There was a problem. [Means for Solving the Problems] The present invention has been made in view of these problems, and the total length of the lens is very short, about three times the combined focal length, and the lens has 4 elements in 4 groups. Although it has a very simple lens structure, about half the number of conventional lenses, it has a wide angle of view of 102° and sufficient brightness of F2.1, and the front lens diameter is small and various aberrations are well corrected. The purpose of this is to obtain an ultra-compact ultra-wide-angle lens. In summary, the ultra-compact ultra-wide-angle lens of the present invention includes, in order from the object side, a first lens of a concave meniscus lens with a convex surface facing the object side, and a concave meniscus lens with a convex surface facing the object side. It consists of a second lens, a third lens that is a convex lens, and a fourth lens that is a convex lens, and has at least one aspherical surface on the positive and negative lenses, and is characterized by satisfying the conditions specified in the following Equations 1 to 4. shall be. [Formula 1] f<|f1,2 |<2f [Formula 2] |f1 |<|f2 | [Formula 3] ν1 <ν2 , ν3 >ν4 [Formula 4] f<
d2 <1.3f However, f: Combined focal length of the entire system fi: Focal length of the i-th lens f1,2
: Combined focal length of the first and second lenses νi : i-th
Abbe's number d2 of lens: The air distance between the first lens and the second lens. [Operation] First, the ultra-compact ultra-wide-angle lens of the present invention shortens the distance between the first and second lenses by making the image side surface of the first lens of the concave lens aspherical. This is to correct the aberrations that occur here. [0008] Furthermore, the ultra-compact ultra-wide-angle lens of the present invention has a convex fourth lens having an aspherical surface.
Spherical aberration, astigmatism, coma, etc., which were previously corrected with three lenses, are now corrected with one lens. The condition of Equation 1 is a condition for constructing a front group divergent system, and is a condition related to astigmatism, coma aberration, and miniaturization of the entire system. When |f1,2| exceeds 2f,
Back focus becomes shorter. Also, it becomes difficult to correct astigmatism, and in order to correct this astigmatism, the second and third
You will have to widen the distance between the lenses. However, in such a case, the total length of the lens becomes long, the meaning of making the image side of the first lens of the concave lens aspherical is lost, and the ultra-miniaturization that is the objective of the present invention cannot be achieved. It disappears. Furthermore, if |f1,2| is shorter than f, the comatic aberration generated in the diverging system becomes extremely large, making it difficult to correct the aberration even if an aspherical lens is used. [0010] Furthermore, the condition of Equation 2 is also a condition for constructing a front group divergent system. If this condition is not met, the diameter of the front lens will become large, making it impossible to achieve the purpose of the invention of ultra-miniaturization, and making it difficult to correct aberrations. [0011] Furthermore, the condition of Equation 3 is related to the correction of lateral chromatic aberration. If this condition is not met, chromatic aberration of magnification becomes large and correction becomes difficult. Furthermore, the condition of Equation 4 is related to the total length of the lens. If d2 is larger than 1.3f, it will be advantageous in terms of aberration correction, but the total lens length will become longer.
Since the diameter of the front lens also increases, it becomes impossible to achieve the ultra-miniaturization objective of the present invention. Furthermore, if d2 is shorter than f, it becomes difficult to correct distortion aberration, and the radius of curvature of the image plane side surface of the first lens becomes very small, making lens processing difficult. [Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in the optical axis cross-sectional view of FIG. 1, the ultra-compact ultra-wide-angle lens of the present invention includes, in order from the object side, a first lens of a concave meniscus lens with a convex surface facing the object side, a first lens with a convex surface facing the object side, and a first lens with a convex surface facing the object side. The second lens is a concave meniscus lens, the third lens is a convex lens, and the fourth lens is a convex lens, and satisfies the conditions defined in Equations 1 to 4 above. In the embodiment shown in FIG. 1, the r2 and r8 surfaces have aspherical surfaces, and the shape of the aspherical surfaces is defined by Equation 5. [Equation 5] However, in Equation 5, Z: the height from the optical axis is y
Distance of a point on the aspheric surface from the tangent plane of the aspheric vertex. y: Height from the optical axis. C: Curvature of aspherical apex (=1/r). ε: Conic constant. D, E, F, G: Aspheric coefficients. shall represent. Next, Table 1 shows specific numerical values of the above embodiment. In the table, r1 to r8 are the radius of curvature of each lens surface sequentially from the object side, d1 to d7 are the wall pressure of each lens or air distance between each lens surface sequentially from the object side, and n1 to n4 are the radius of curvature of each lens surface sequentially from the object side. ν1 to ν4 indicate the refractive index of each lens sequentially from the object side, and Abbe numbers of each lens sequentially from the object side. FIG. 2 shows the spherical aberration of the above example, FIG. 3 shows the astigmatism of the above example, and FIG. 4 shows the distortion aberration of the above example.
FIG. 5 shows the chromatic aberrations of the above embodiments. Further, in these characteristic curves, d indicates the d line, F the F line, C the C line, and SC indicates the sine condition. Further, in FIG. 3, S indicates the sagittal direction, and M indicates the meridional direction. [Table 1] [Effects of the Invention] According to the present invention, as seen in the above embodiments and aberration curves, the total lens length is very short, about three times the focal length, and Although it is extremely simple and has a small number of elements, with 4 elements in 4 groups, which is about half the number of elements in the lens, it covers a wide range of angle of view of 102 degrees and has sufficient brightness with an F number of 2.1. This makes it possible to obtain an ultra-compact, ultra-wide-angle lens that has a small front lens diameter and has various aberrations well corrected, and has characteristics suitable as a lens for in-vehicle cameras and surveillance cameras. be able to. [0019]
【図１】本発明の実施例に係る超広角レンズの光軸断面
図である。FIG. 1 is an optical axis cross-sectional view of an ultra-wide-angle lens according to an embodiment of the present invention.
【図２】上記実施例の球面収差を示す図。FIG. 2 is a diagram showing spherical aberration in the above example.
【図３】上記実施例の非点収差を示す図。FIG. 3 is a diagram showing astigmatism in the above example.
【図４】上記実施例の歪曲収差を示す図。FIG. 4 is a diagram showing distortion aberration in the above example.
【図５】上記実施例の色収差を示す図。FIG. 5 is a diagram showing chromatic aberration in the above example.
１ 第１レンズ ２ 第２レンズ ３ 第３レンズ ４ 第４レンズ 1 First lens 2 Second lens 3 Third lens 4 4th lens
Claims (1)
けた凹メニスカスレンズの第１レンズ，前記物体側に凸
面を向けた凹メニスカスレンズの第２レンズ，凸レンズ
の第３レンズ，凸レンズの第４レンズからなり，正負の
レンズに少なくとも１面の非球面を有し，次の（１），
（２），（３） 及び（４） の条件を満足することを
特徴とする超小型超広角レンズ。 （１） ｆ＜｜ｆ１，２ ｜＜２ｆ （２） ｜ｆ１ ｜＜｜ｆ２ ｜ （３） ν１ ＜ν２ ，ν３ ＞ν４ （４） ｆ＜
ｄ２ ＜１．３ｆ 但し， ｆ ：全系の合成焦点距離 ｆｉ ：第ｉレンズの焦点距離ｆ１，２
：第１，２レンズの合成焦点距離νｉ ：第ｉ
レンズのアッベ数ｄ２ ：第１レンズと第２レ
ンズの空気間隔とする。1. In order from the object side, a first lens of a concave meniscus lens with a convex surface facing the object side, a second lens of a concave meniscus lens with a convex surface facing the object side, a third lens of a convex lens, and a convex lens. The positive and negative lenses have at least one aspherical surface, and the following (1),
An ultra-compact ultra-wide-angle lens characterized by satisfying the conditions (2), (3), and (4). (1) f<|f1,2 |<2f (2) |f1 |<|f2 | (3) ν1 <ν2 , ν3 >ν4 (4) f<
d2 <1.3f However, f: Combined focal length of the entire system fi: Focal length of the i-th lens f1,2
: Combined focal length of the first and second lenses νi : i-th
Abbe's number d2 of lens: The air distance between the first lens and the second lens.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3021678A JP2975696B2 (en) | 1991-01-22 | 1991-01-22 | Ultra-compact ultra-wide-angle lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3021678A JP2975696B2 (en) | 1991-01-22 | 1991-01-22 | Ultra-compact ultra-wide-angle lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04238312A true JPH04238312A (en) | 1992-08-26 |
| JP2975696B2 JP2975696B2 (en) | 1999-11-10 |
Family
ID=12061724
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3021678A Expired - Fee Related JP2975696B2 (en) | 1991-01-22 | 1991-01-22 | Ultra-compact ultra-wide-angle lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2975696B2 (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5774279A (en) * | 1995-10-19 | 1998-06-30 | Konica Corporation | Retrofoucus photographic lens |
| JP2001159732A (en) * | 1999-12-02 | 2001-06-12 | Nikon Corp | Super wide angle lens and photographic device having the lens |
| US7405890B2 (en) | 2006-02-03 | 2008-07-29 | Enplas Corporation | Imaging lens |
| WO2008091073A1 (en) * | 2007-01-23 | 2008-07-31 | Seung-Tae Jeong | The rectifying filter of image formation surface's brightness in lens using equipment |
| GB2447536A (en) * | 2007-03-13 | 2008-09-17 | Samsung Electro Mech | Subminiature imaging optical system |
| WO2010143662A1 (en) * | 2009-06-12 | 2010-12-16 | 株式会社オプトエレクトロニクス | Optical information reading device |
| CN103499874A (en) * | 2013-10-29 | 2014-01-08 | 姚学文 | Extra wide angle lens |
| CN105629439A (en) * | 2016-01-19 | 2016-06-01 | 北京大学 | Lens assembly used for wireless optical communication receiving |
| CN113031216A (en) * | 2021-03-23 | 2021-06-25 | 浙江舜宇光学有限公司 | Optical imaging system |
| US11163134B2 (en) | 2018-12-20 | 2021-11-02 | Largan Precision Co., Ltd. | Imaging lens system, identification module and electronic device |
| US11327277B2 (en) | 2019-11-29 | 2022-05-10 | Largan Precision Co., Ltd. | Lens system and electronic device |
-
1991
- 1991-01-22 JP JP3021678A patent/JP2975696B2/en not_active Expired - Fee Related
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5774279A (en) * | 1995-10-19 | 1998-06-30 | Konica Corporation | Retrofoucus photographic lens |
| JP2001159732A (en) * | 1999-12-02 | 2001-06-12 | Nikon Corp | Super wide angle lens and photographic device having the lens |
| US7405890B2 (en) | 2006-02-03 | 2008-07-29 | Enplas Corporation | Imaging lens |
| WO2008091073A1 (en) * | 2007-01-23 | 2008-07-31 | Seung-Tae Jeong | The rectifying filter of image formation surface's brightness in lens using equipment |
| GB2447536A (en) * | 2007-03-13 | 2008-09-17 | Samsung Electro Mech | Subminiature imaging optical system |
| US7755851B2 (en) | 2007-03-13 | 2010-07-13 | Samsung Electro-Mechanics Co., Ltd. | Subminiature imaging optical system |
| WO2010143662A1 (en) * | 2009-06-12 | 2010-12-16 | 株式会社オプトエレクトロニクス | Optical information reading device |
| JP2010286740A (en) * | 2009-06-12 | 2010-12-24 | Optoelectronics Co Ltd | Optical information reading apparatus |
| CN103499874A (en) * | 2013-10-29 | 2014-01-08 | 姚学文 | Extra wide angle lens |
| CN105629439A (en) * | 2016-01-19 | 2016-06-01 | 北京大学 | Lens assembly used for wireless optical communication receiving |
| CN105629439B (en) * | 2016-01-19 | 2018-06-01 | 北京大学 | The lens assembly received applied to wireless light communication |
| US11163134B2 (en) | 2018-12-20 | 2021-11-02 | Largan Precision Co., Ltd. | Imaging lens system, identification module and electronic device |
| US11327277B2 (en) | 2019-11-29 | 2022-05-10 | Largan Precision Co., Ltd. | Lens system and electronic device |
| US11640046B2 (en) | 2019-11-29 | 2023-05-02 | Largan Precision Co., Ltd. | Lens system and electronic device |
| US11940598B2 (en) | 2019-11-29 | 2024-03-26 | Largan Precision Co., Ltd. | Lens system and electronic device |
| CN113031216A (en) * | 2021-03-23 | 2021-06-25 | 浙江舜宇光学有限公司 | Optical imaging system |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2975696B2 (en) | 1999-11-10 |
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