JP2622155B2 - Aspheric single lens - Google Patents
Aspheric single lensInfo
- Publication number
- JP2622155B2 JP2622155B2 JP63168181A JP16818188A JP2622155B2 JP 2622155 B2 JP2622155 B2 JP 2622155B2 JP 63168181 A JP63168181 A JP 63168181A JP 16818188 A JP16818188 A JP 16818188A JP 2622155 B2 JP2622155 B2 JP 2622155B2
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- aspherical
- single lens
- lens
- aspheric
- condition
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Description
【発明の詳細な説明】 （発明の技術分野） 本発明は、非球面を有する単レンズに関しとりわけNA
が0.42〜0.47程度の非球面単レンズに関するものであ
る。Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a single lens having an aspherical surface, and
Is related to an aspheric single lens of about 0.42 to 0.47.
（従来技術） 近年、ビデオテイスクやコンパクトデイスク等の光デ
イスクが大記憶容量の記録担体として多岐に亘り使用さ
れている。(Prior Art) In recent years, optical disks such as video disks and compact disks have been widely used as record carriers having a large storage capacity.
又、光デイスク同様の光学的な記録担体として、記憶
容量の多さ、携帯性の良さ等の利点を有する光カードも
目的を浴びている。Also, as an optical record carrier similar to an optical disc, an optical card having advantages such as a large storage capacity and a good portability has also been focused.
この種の記録担体に情報を高密度に記録したり、記録
情報を正確に再生する為に、情報記録再生装置に用いる
対物レンズには数μｍの分解能が要求される。即ち、0.
4を上回るNAの対物レンズが必要である。In order to record information on this type of record carrier at high density and to accurately reproduce recorded information, an objective lens used in an information recording / reproducing apparatus requires a resolution of several μm. That is, 0.
An objective lens with a NA of more than 4 is required.
又、上記用途の対物レンズにおいては、光デイスクや
光カード等の担体表面と対物レンズとの間隔を十分にと
り、両者の接触を防止して記録媒体や対物レンズの損傷
を回避する必要もある。Further, in the objective lens for the above-mentioned application, it is necessary to provide a sufficient distance between the surface of a carrier such as an optical disk or an optical card and the objective lens, to prevent contact between the two, and to avoid damage to the recording medium and the objective lens.
更に、上述の情報記録再生装置では、オートフオーカ
スやオートトラツキングを行う為に対物レンズを光軸方
向や光軸方向と直交する方向に移動させる方式が主流で
ある。依って、応答特性を向上させる為に、この種の対
物レンズには小型化・軽量化が要求される。Further, in the above-mentioned information recording / reproducing apparatus, a method of moving an objective lens in an optical axis direction or a direction orthogonal to the optical axis direction in order to perform auto focusing and auto tracking is mainly used. Therefore, in order to improve the response characteristics, this type of objective lens is required to be reduced in size and weight.
従来、この種の対物レンズとして、特開昭58−42021
号公報、特開昭58−208719号公報、特開昭60−122915号
公報等に４群４枚の構成から成るレンズ系が開示されて
いる。Conventionally, as this kind of objective lens, Japanese Patent Laid-Open No. 58-42021
JP-A-58-208719, JP-A-60-122915, and the like disclose a lens system composed of four groups and four elements.
しかしながら、これらの公開公報に示された対物レン
ズはレンズ系の全長が大きく、前述の小型化・軽量化を
図ることができない。However, the objective lenses disclosed in these publications have a large overall length of the lens system, and cannot be reduced in size and weight as described above.
上記の欠点を解消するため、最近は非球面単レンズの
開発が盛んであり、例えば特開昭60−250320号公報，特
開昭61−148413号公報，特開昭63−58311号公報，特開
昭63−58312号公報等に技術開示されている。In order to solve the above-mentioned drawbacks, aspheric single lenses have recently been actively developed. For example, JP-A-60-250320, JP-A-61-148413, JP-A-63-58311, and The technology is disclosed in, for example, JP-A-63-58312.
しかしながら、上記公報に示された非球面単レンズは
光ディスクの仕様に併せて設計されたものであり、光カ
ード等の情報記録面を被う保護層が光デイスクの保護層
に比較して薄い記録担体に対して使用する場合にははな
はだ不適当である。However, the aspherical single lens disclosed in the above publication is designed in accordance with the specification of an optical disk, and a protective layer covering an information recording surface of an optical card or the like is thinner than a protective layer of an optical disk. When used on a carrier, it is very unsuitable.
光カードの厚さは、一般に流通している磁気カードの
厚さと同程度の0.8mm程度である為、光カードの強度等
を考慮すると、光カードに於ける透明保護層の厚さｔは
略々0.4mm程度となる。Since the thickness of the optical card is about 0.8 mm, which is about the same as the thickness of a generally distributed magnetic card, the thickness t of the transparent protective layer in the optical card is approximately Each becomes about 0.4mm.
上記公開公報に示される非球面単レンズの実施例にお
いては、レンズの焦点距離をＦとすると、実施例中に示
されるレンズが適用可能な記録担体の透明保護層の厚さ
ｔは、0.26F〜0.28F程度である。従って光カードにおけ
る透明保護層の厚さｔ＝0.4mmに対して適切である対物
レンズの焦点距離Ｆは1.43〜1.54mmと成る。In the embodiment of the aspherical single lens disclosed in the above publication, assuming that the focal length of the lens is F, the thickness t of the transparent protective layer of the record carrier to which the lens shown in the embodiment can be applied is 0.26F It is about 0.28F. Therefore, the focal length F of the objective lens which is appropriate for the thickness t = 0.4 mm of the transparent protective layer in the optical card is 1.43 to 1.54 mm.
ところがこの場合には、曲率半径が小さくなり過ぎて
製作が極めて困難であること、更に、回折限界とみなせ
る良好な結像特性を有する領域（像高）が極めてせまい
こと等の欠点があり殆ど実用的ではない。However, in this case, there is a drawback that the radius of curvature is too small to manufacture, and furthermore, a region (image height) having a good imaging characteristic which can be regarded as a diffraction limit is extremely small, and thus it is almost practically used. Not a target.
従って実用的な対策としては、対物レンズと光カード
との間に保護層の厚み補正用の平行平板を介在させて使
用する手段が挙げられる。即ち、前記従来例の対物レン
ズの焦点距離を製作が容易なＦ＝4.5mm程度に設定す
る。この時必要な保護層の厚みは1.17〜1.26mmであり、
他方光カードの保護層の厚みは0.4mmであるから、その
差の0.77〜0.86mm程度の厚みを有する平行平板を使用す
れば良いことになる。Therefore, as a practical measure, there is a means of using a parallel plate for correcting the thickness of the protective layer between the objective lens and the optical card. That is, the focal length of the conventional objective lens is set to about F = 4.5 mm, which facilitates manufacture. At this time, the required thickness of the protective layer is 1.17 to 1.26 mm,
On the other hand, since the thickness of the protective layer of the optical card is 0.4 mm, a parallel flat plate having a difference of about 0.77 to 0.86 mm may be used.
しかしながら、この方法も光学系の小型・軽量化によ
る性能改善、部品点数の減少に伴なう低コスト化の要望
に反するものであり好ましくない。However, this method is also unfavorable because it contradicts demands for performance improvement by reducing the size and weight of the optical system and cost reduction accompanying a decrease in the number of parts.
更に、情報の記録を行う光メモリ装置に用いられる光
ヘツドにおいて、半導体レーザからの発散光束を光量の
損失が少ない状態で効率良く平行光束化するコリメータ
レンズとして、上記の従来例に示されるレンズを使用す
る場合にも同様の欠点が指摘されている。即ち、通常の
半導体レーザに装着されている保護用ガラス平板の厚み
ｔは略々0.25〜0.35mmであるからである。Further, in the optical head used in the optical memory device for recording information, the lens shown in the above-mentioned conventional example is used as a collimator lens which efficiently converts a divergent light beam from a semiconductor laser into a parallel light beam with little loss of light amount. However, similar drawbacks have been pointed out. That is, the thickness t of the protective glass plate mounted on the ordinary semiconductor laser is approximately 0.25 to 0.35 mm.
（発明の概略） 本発明の目的は、上記従来の欠点を解消し、厚みｔが
略々0.04F〜0.111Fの平行平板を介して、１゜程度の画
角の範囲内で良好に収差補正の成された非球面単レンズ
を提供することにある。(Summary of the Invention) An object of the present invention is to solve the above-mentioned conventional drawbacks and to satisfactorily correct aberrations within a range of an angle of view of about 1 ° through a parallel flat plate having a thickness t of approximately 0.04F to 0.111F. An object of the present invention is to provide an aspherical single lens having the following characteristics.
本発明の上記目的は、以下に述べる本発明の非球面単
レンズにより達成される。The above object of the present invention is achieved by an aspheric single lens of the present invention described below.
（実施例） 本発明による非球面単レンズは、物界側の面が非球
面、像界側の面が球面である非球面単レンズにおいて、
該非球面が、該非球面の近軸曲率をR1、該非球面上の任
意の点から非球面頂点の接平面までの距離をＸ、前記任
意の点から光軸までの距離をＨとした時に下記の式にて
表わされる非球面であり、前記球面の曲率半径がR2であ
ると共に次の条件（１），（２），（３）を満足する非
球面単レンズ。(Example) An aspherical single lens according to the present invention is an aspherical single lens whose surface on the object side is aspherical and whose surface on the image side is spherical.
When the aspheric surface has a paraxial curvature of the aspheric surface R 1 , a distance from an arbitrary point on the aspheric surface to a tangent plane of the aspherical vertex is X, and a distance from the arbitrary point to the optical axis is H, the following is given. of a non-spherical surface represented by a formula, the following conditions along with the radius of curvature of the spherical surface is R 2 (1), (2), the aspheric single lens satisfies (3).
ただし、Aiは非球面の非球面係数、Ｆは非球面単レン
ズの焦点距離、Ｄは非球面単レンズの光軸上肉厚、Ｎは
非球面単レンズの使用波長に対する屈折率である。 Here, Ai is the aspherical coefficient of the aspherical surface, F is the focal length of the aspherical single lens, D is the thickness on the optical axis of the aspherical single lens, and N is the refractive index of the aspherical single lens with respect to the used wavelength.
次に条件（１）から（３）について説明する。 Next, conditions (1) to (3) will be described.
本発明の条件（１），（２）は３次の領域で球面収差
及びコマ収差を良好に補正するためのものである。The conditions (1) and (2) of the present invention are for favorably correcting spherical aberration and coma in the third order region.
松居吉哉著「レンズ設計法」（共立出版）によれば、
第１面，第２面の３次の球面収差係数I1,I2及び第１
面，第２面のコマ収差係数II1,II2は、入射瞳を第１面
に一致させ物体距離が無限遠の場合、次の様に表わされ
る。According to Yoshiya Matsui, "Lens Design Method" (Kyoritsu Publishing)
Third-order spherical aberration coefficients I 1 and I 2 of the first surface and the second surface and the first
The coma aberration coefficients II 1 and II 2 of the surface and the second surface are expressed as follows when the entrance pupil coincides with the first surface and the object distance is infinity.
ここで、ψ１は第１面の３次の非球面項であり、R1は
第１面の近軸曲率半径、R2は第２面の曲率半径である。 Here, [psi 1 is a third-order aspheric term of the first surface, R 1 is a paraxial radius of curvature of the first surface, R 2 is the radius of curvature of the second surface.
そして、レンズ全体の３次の球面収差係数Ｉ及びコマ
収差係数IIは各面のそれぞれの収差係数の和、 Ｉ＝I1＋I2 II＝II1＋II2 で求まり、I,IIが適切な値となるようにレンズ形状及び
各非球面量を定める。The third-order spherical aberration coefficient I and coma aberration coefficient II of the entire lens are obtained by the sum of the respective aberration coefficients of each surface, I = I 1 + I 2 II = II 1 + II 2 , and I and II are appropriate values. The lens shape and the amount of each aspheric surface are determined so that
上述した式より明らかな様に、レンズの形状（焦点距
離，作動距離など）が決まるとR1,R2,D,Nの値はほぼ定
まってしまい、収差係数I1を適切な値にするために残さ
れる自由度はψ１しかない。従って、レンズ形状もある
程度収差補正を考慮した上で決められることが必要で、
そのための数値範囲が条件（１），（２）である。As is clear from the above equation, when the shape of the lens (focal length, working distance, etc.) is determined, the values of R 1 , R 2 , D, and N are almost determined, and the aberration coefficient I 1 is set to an appropriate value. Is only 1 degree of freedom. Therefore, it is necessary that the lens shape is determined in consideration of aberration correction to some extent.
The numerical range for that is the conditions (1) and (2).
条件（１）の数値範囲を外れると、特に第１面の球面
収差が大きくなり、第１面の非球面項ψ１では収差が補
正しきれなくなる。Outside the numerical range of Condition (1), in particular made spherical aberration of the first surface is large, aspheric term [psi 1 in aberration of the first surface is not completely corrected.
条件（２）は第２面でコマ収差をバランス良く補正す
るための条件であり、この数値範囲を外れると軸外の結
像性能が著しく劣化する。The condition (2) is a condition for correcting the coma aberration on the second surface in a well-balanced manner. If the value is out of this numerical range, the off-axis imaging performance is significantly deteriorated.
条件（３）は主に正弦条件を満足させるための条件で
ある。本発明においては軸上収差と共に一定範囲内の軸
外収差、特に、コマ収差を良好に補正しているが、条件
（３）の範囲を外れるとアイソプラナテイツクな条件が
著しく失なわれ好ましくないものである。Condition (3) is a condition mainly for satisfying the sine condition. In the present invention, the off-axis aberration within a certain range together with the on-axis aberration, particularly the coma aberration, is favorably corrected. However, if it is out of the range of the condition (3), the isoplanatic condition is remarkably lost. Not something.
以下に本発明の非球面単レンズの実施例を示す。 Hereinafter, examples of the aspherical single lens of the present invention will be described.
ただし第１図に示す様に、Ｆはレンズの焦点距離、NA
は開口数、βは近軸横倍率、R1は第１面の非球面の近軸
曲率半径、R2は第２面の曲率半径、Ｄはレンズの中心肉
厚、W.Dは作動距離、ｔは平行平板の厚み、Ｎは使用波
長λ＝830nmでのレンズの屈折率、Ntは使用波長λ＝830
nmでの平行平板の屈折率、△（ｊ）は第１面においてNA
（開口数）で決まるレンズ有効径内のｊ割における非球
面と近軸曲率半径R1を有する球面との光軸方向の差（但
し、△（ｊ）は非球面の曲率が弱くなる方向を正とす
る。）である。However, as shown in FIG. 1, F is the focal length of the lens, NA
Is the numerical aperture, β is the paraxial lateral magnification, R 1 is the paraxial radius of curvature of the aspheric surface of the first surface, R 2 is the radius of curvature of the second surface, D is the center thickness of the lens, WD is the working distance, t Is the thickness of the parallel plate, N is the refractive index of the lens at the used wavelength λ = 830 nm, and Nt is the used wavelength λ = 830.
The refractive index of the parallel plate in nm, △ (j) is the NA at the first surface
The difference in the optical axis direction of the spherical surface having an aspherical surface and the paraxial radius of curvature R 1 in the lens effective diameter of the j split determined by the (numerical aperture) (where, △ a (j) the direction in which the curvature of the aspherical surface weakens Positive).
尚、非球面の形状は、第１面の頂点を原点とし、光軸
方向をＸ軸、入射高をＨとして次式で表わすものとす
る。Note that the shape of the aspheric surface is represented by the following equation, with the vertex of the first surface as the origin, the optical axis direction as the X axis, and the incident height as H.
ただし、Aiは非球面の非球面係数である。 Here, A i is the aspheric coefficient of the aspheric surface.
また、第２図，第３図，第４図は夫々本発明の実施例
1,2,3のレンズの収差図である。ここでは、球面収差、
非点収差及び歪曲収差を示してあり、SAは球面収差、SC
は正弦条件不満足量、Ｍはメリジオナル面の像面彎曲、
Ｓはサジタル面の像面彎曲を表わす。2, 3, and 4 each show an embodiment of the present invention.
FIG. 4 is an aberration diagram of lenses 1, 2, and 3. Here, spherical aberration,
Astigmatism and distortion are shown, SA is spherical aberration, SC
Is the sine condition unsatisfactory amount, M is the field curvature of the meridional surface,
S represents the field curvature of the sagittal plane.
実施例１ Ｆ＝１ NA＝0.42 β＝０ R1＝0.66492 Ｄ＝0.50998 Ｎ＝1.57532 R2＝−3.07363 Ｗ・Ｄ＝0.66114 ｔ＝0.08869 Nt＝1.510 A3 ＝ 1.07364×10-3 A4 ＝−3.22236×10-1 A5 ＝ 3.33809×10-2 A6 ＝−8.87436×10-1 A7 ＝ 1.64843×10-1 A8 ＝ 1.43683×100 A9 ＝−6.21185×10-1 A10＝−8.23827×100 A11＝ 3.80363×100 A12＝−3.17809×101 A13＝ 1.01975×101 A14＝ 7.92322×101 A15＝ 1.59923×102 A16＝−2.51141×102 △（10）＝0.0145 △（７）＝0.00287 △（５）＝0.000683 実施例２ Ｆ＝１ NA＝0.42 β＝０ R1＝0.66619 Ｄ＝0.55455 Ｎ＝1.57532 R2＝−2.93558 Ｗ・Ｄ＝0.63722 ｔ＝0.08873 Nt＝1.510 A3 ＝−8.40983×10-4 A4 ＝−3.02781×10-1 A5 ＝ 2.47153×10-2 A6 ＝−9.33993×10-1 A7 ＝ 1.69352×10-1 A8 ＝ 1.42370×100 A9 ＝−5.37801×10-1 A10＝−8.22846×100 A11＝ 7.22155×100 A12＝−3.20163×101 A13＝−2.01815×100 A14＝ 8.00188×101 A15＝ 1.59936×102 A16＝−2.43559×102 △（10）＝0.0141 △（７）＝0.00277 △（５）＝0.000660 実施例３ Ｆ＝１ NA＝0.42 β＝０ R1＝0.66596 Ｄ＝0.59874 Ｎ＝1.57532 R2＝−2.83915 Ｗ・Ｄ＝0.61290 ｔ＝0.08870 Nt＝1.510 A3 ＝ 8.84494×10-4 A4 ＝−3.12656×10-1 A5 ＝ 4.62533×10-2 A6 ＝−9.27195×10-1 A7 ＝ 2.52054×10-1 A8 ＝ 1.38085×100 A9 ＝−2.65325×10-1 A10＝−8.99677×100 A11＝ 5.88371×100 A12＝−3.24364×101 A13＝−4.47417×100 A14＝ 7.87561×101 A15＝ 1.19524×102 A16＝−8.70558×101 △（10）＝0.0139 △（７）＝0.00274 △（５）＝0.000652 以上示した実施例1,2,3においては焦点距離Ｆを4.5mm
とし、NAを0.42、平行平板の厚さｔを0.4mmとして設計
したものであり、略々１゜の画角範囲内において回折限
界に近い結像性能を有する。更に平行平板の厚さｔは、
上記NA,画角の条件下では±0.1mm程度の変動までは良好
な結像性能を有する。即ち、0.065F＜ｔ＜0.111Fの範囲
であれば良好な結像性能が得られる。Example 1 F = 1 NA = 0.42 β = 0 R 1 = 0.66492 D = 0.50998 N = 1.57532 R 2 = −3.07363 WD = 0.66114 t = 0.08869 Nt = 1.510 A 3 = 1.07364 × 10 −3 A 4 = − 3.22236 × 10 -1 A 5 = 3.33809 × 10 -2 A 6 = −8.87436 × 10 −1 A 7 = 1.64843 × 10 −1 A 8 = 1.43683 × 10 0 A 9 = −6.21185 × 10 −1 A 10 = − 8.23827 x 10 0 A 11 = 3.80363 x 10 0 A 12 =-3.17809 x 10 1 A 13 = 1.01975 x 10 1 A 14 = 7.92322 x 10 1 A 15 = 1.59923 x 10 2 A 16 = -2.51141 x 10 2 Δ (10) = 0.0145 Δ (7) = 0.00287 Δ (5) = 0.000683 Example 2 F = 1 NA = 0.42 β = 0 R 1 = 0.66619 D = 0.54555 N = 1.57532 R 2 = −2.93558 WD = 0.63722 t = 0.08873 Nt = 1.510 A 3 = −8.40983 × 10 −4 A 4 = −3.02781 × 10 −1 A 5 = 2.47153 × 10 −2 A 6 = −9.33993 × 10 −1 A 7 = 1.69352 × 10 −1 A 8 = 1.42370 x 10 0 A 9 = -5.37801 x 10 -1 A 10 = -8.22846 x 10 0 A 11 = 7.22155 x 10 0 A 12 =-3.20163 x 10 1 A 13 = -2.01815 x 10 0 A 14 = 8.00188 × 10 1 A 15 = 1.59936 × 10 2 A 16 = −2.43559 × 10 2 Δ (10) = 0.0141 Δ (7) = 0.00277 Δ (5) = 0.000660 Example 3 F = 1 NA = 0.42 β = 0 R 1 = 0.66596 D = 0.59874 N = 1.57532 R 2 = −2.83915 W · D = 0.61290 t = 0.08870 Nt = 1.510 A 3 = 8.884494 × 10 -4 A 4 = −3.12656 × 10 −1 A 5 = 4.62533 × 10 −2 A 6 = −9.27 195 × 10 −1 A 7 = 2.52054 × 10 −1 A 8 = 1.38085 x 10 0 A 9 = -2.65325 x 10 -1 A 10 = -8.99677 x 10 0 A 11 = 5.88 371 x 10 0 A 12 =-3.24364 x 10 1 A 13 = -4.47417 x 10 0 A 14 = 7.87561 x 10 1 A 15 = 1.19524 × 10 2 A 16 = −8.70558 × 10 1 Δ (10) = 0.0139 Δ (7) = 0.00274 Δ (5) = 0.000652 In Examples 1, 2, and 3 described above, the focal length F was 4.5 mm.
It is designed to have an NA of 0.42 and a thickness t of the parallel plate of 0.4 mm, and has an imaging performance close to the diffraction limit within a viewing angle range of approximately 1 °. Further, the thickness t of the parallel plate is
Under the conditions of the NA and the angle of view described above, good imaging performance is obtained up to a fluctuation of about ± 0.1 mm. That is, in the range of 0.065F <t <0.111F, good imaging performance can be obtained.
上述した実施例1,2,3に見られるように、 の本発明の非球面単レンズにおいては上述した（１）か
ら（３）の条件に加えて、以下の条件（４）から（６）
を満足することが好ましい。As seen in Examples 1, 2, and 3 above, In the aspherical single lens of the present invention, in addition to the above-mentioned conditions (1) to (3), the following conditions (4) to (6)
Is preferably satisfied.
条件（４），（５）は３次の領域で球面収差及びコマ
収差を良好に補正するためのものである。 The conditions (4) and (5) are for favorably correcting spherical aberration and coma in the third order region.
条件（４）の数値範囲を外れると、特に第１面の球面
収差が大きくなり、第１面の非球面項ψ１では収差が補
正しきれなくなる。Outside the numerical range of Condition (4), in particular made spherical aberration of the first surface is large, aspheric term [psi 1 in aberration of the first surface is not completely corrected.
条件（５）は第２面でコマ収差をバランス良く補正す
るための条件であり、この数値範囲を外れると軸外の結
像性能が著しく劣化する。The condition (5) is a condition for correcting the coma aberration on the second surface in a well-balanced manner. If the value is out of this numerical range, the off-axis imaging performance is significantly deteriorated.
条件（６）は主に正弦条件を満足させるための条件で
ある。本発明においては軸上収差と共に一定範囲内の軸
外収差、特に、コマ収差を良好に補正しているが、条件
（６）の範囲を外れるとアイソプラナテイツクな条件が
著しく失なわれ好ましくないものである。Condition (6) is a condition mainly for satisfying the sine condition. In the present invention, the off-axis aberration within a certain range together with the on-axis aberration, in particular, the coma aberration, is favorably corrected. However, if it is out of the range of the condition (6), the isoplanatic condition is remarkably lost, so that it is preferable. Not something.
更に、 の本発明の非球面単レンズにおいては上述した（１）か
ら（６）の条件に加えて、以下の条件（７）から（９）
を満足することにより、特に球面収差を良好に補正しう
るものである。Furthermore, In the aspherical single lens of the present invention, in addition to the conditions (1) to (6) described above, the following conditions (7) to (9)
Is satisfied, in particular, spherical aberration can be favorably corrected.
（７）0.01F＜△（10）＜0.02F （８）0.0025F＜△（７）＜0.0035F （９）０＜△（５）＜0.001F 条件式（７）〜（９）のいずれの１つの条件式にあっ
ても、その範囲の下限値を下回って、その位置における
非球面量が少ない場合には、その位置を通過する光線の
球面収差が補正不足となる。逆に条件式（７）〜（９）
のいずれの１つの条件式にあっても、その範囲の上限値
を上回った場合には、その位置を通過する光線の球面収
差が補正過剰となってくるので好ましくない。(7) 0.01F <△ (10) <0.02F (8) 0.0025F <△ (7) <0.0035F (9) 0 <△ (5) <0.001F Any of the conditional expressions (7) to (9) Even with one conditional expression, if the aspherical amount at the position is smaller than the lower limit of the range and the amount of aspherical surface at the position is small, the spherical aberration of the light beam passing through the position will be insufficiently corrected. Conversely, conditional expressions (7) to (9)
In any one of the conditional expressions, if the value exceeds the upper limit of the range, it is not preferable because the spherical aberration of the light beam passing through the position becomes excessively corrected.
特に好ましい条件は、 0.013F＜△（10）＜0.016F 0.0026F＜△（７）＜0.003F 0.0005F＜△（５）＜0.0008F を同時に満足する場合であって、この時、球面収差が一
段と良好に補正可能である。A particularly preferable condition is a case where 0.013F <△ (10) <0.016F 0.0026F <△ (7) <0.003F 0.0005F <△ (5) <0.0008F is satisfied at the same time. The correction can be made even better.
以下に本発明の非球面単レンズの他の実施例を示す。 Hereinafter, other embodiments of the aspherical single lens of the present invention will be described.
ただし、第１図に示す様に、Ｆはレンズの焦点距離、
NAは開口数、βは近軸横倍率、R1は第１面の非球面の近
軸曲率半径、R2は第２面の曲率半径、Ｄはレンズの中心
肉厚、W.Dは作動距離、ｔは平行平板の厚み、Ｎは使用
波長λ＝830nmのレンズの屈折率、Ntは使用波長λ＝830
nmでの平行平板の屈折率、△（ｊ）は第１面においてNA
（開口数）で決まるレンズ有効径内のｊ割における非球
面と近軸曲率半径R1を有する球面との光軸方向の差（但
し、△（ｊ）は非球面の曲率が弱くなる方向を正とす
る。）である。However, as shown in FIG. 1, F is the focal length of the lens,
NA is the numerical aperture, β is the paraxial lateral magnification, R 1 is the paraxial radius of curvature of the aspheric surface of the first surface, R 2 is the radius of curvature of the second surface, D is the center thickness of the lens, WD is the working distance, t is the thickness of the parallel plate, N is the refractive index of the lens having the used wavelength λ = 830 nm, and Nt is the used wavelength λ = 830.
The refractive index of the parallel plate in nm, △ (j) is the NA at the first surface
The difference in the optical axis direction of the spherical surface having an aspherical surface and the paraxial radius of curvature R 1 in the lens effective diameter of the j split determined by the (numerical aperture) (where, △ a (j) the direction in which the curvature of the aspherical surface weakens Positive).
尚、非球面の形状は第１面の頂点を原点とし、光軸方
向をＸ軸、入射高をＨとして次式で表わすものとする。The shape of the aspheric surface is represented by the following equation, with the vertex of the first surface as the origin, the optical axis direction as the X axis, and the incident height as H.
ただし、Aiは非球面の非球面係数である。 Here, A i is the aspheric coefficient of the aspheric surface.
また、第５図，第６図，第７図は夫々本発明の実施例
4,5,6のレンズの収差図である。ここでは、球面収差、
非点収差及び歪曲収差を示してあり、SAは球面収差、SC
は正弦条件不満足量、Ｍはメリジオナル面の像面彎曲、
Ｓはサジタル面の像面彎曲を表わす。FIGS. 5, 6, and 7 each show an embodiment of the present invention.
FIG. 4 is an aberration diagram of lenses 4, 5, and 6. Here, spherical aberration,
Astigmatism and distortion are shown, SA is spherical aberration, SC
Is the sine condition unsatisfactory amount, M is the field curvature of the meridional surface,
S represents the field curvature of the sagittal plane.
実施例４ Ｆ＝１ NA＝0.47 β＝０ R1＝0.66341 Ｄ＝0.59057 Ｎ＝1.57532 R2＝−2.92401 Ｗ・Ｄ＝0.63075 ｔ＝0.06664 Nt＝1.510 A3 ＝−1.79492×10-3 A4 ＝−2.89514×10-1 A5 ＝−1.07562×10-2 A6 ＝−8.86676×10-1 A7 ＝−7.28447×10-2 A8 ＝ 1.89222×100 A9 ＝−3.96149×10-1 A10＝−8.60400×100 A11＝ 9.14741×100 A12＝−3.21268×101 A13＝−2.72974×100 A14＝ 1.09795×102 A15＝−4.75359×101 A16＝−4.27544×101 △（10）＝0.0247 △（７）＝0.00455 △（５）＝0.00106 実施例５ Ｆ＝１ NA＝0.47 β＝０ R1＝0.66640 Ｄ＝0.60087 Ｎ＝1.57532 R2＝−2.82336 Ｗ・Ｄ＝0.62656 ｔ＝0.06664 Nt＝1.510 A3 ＝−3.66687×10-3 A4 ＝−2.85971×10-1 A5 ＝ 2.55345×10-3 A6 ＝−9.68717×10-1 A7 ＝ 8.75908×10-1 A8 ＝−6.77540×10-1 A9 ＝−2.38760×10-2 A10＝−7.73731×100 A11＝ 1.03144×101 A12＝−2.57036×101 A13＝ 6.94092×101 A14＝−7.92054×101 A15＝ 4.77916×101 A16＝−4.95151×101 △（10）＝0.0244 △（７）＝0.00451 △（５）＝0.00106 実施例６ Ｆ＝１ NA＝0.47 β＝０ R1＝0.66479 Ｄ＝0.62217 Ｎ＝1.57532 R2＝−2.81358 Ｗ・Ｄ＝0.61406 ｔ＝0.06665 Nt＝1.510 A3 ＝−2.57035×10-3 A4 ＝−2.82912×10-1 A5 ＝ 6.30130×10-3 A6 ＝−9.43127×10-1 A7 ＝−5.10797×10-2 A8 ＝ 1.90007×100 A9 ＝−1.92226×10-1 A10＝−9.04979×100 A11＝ 9.13503×100 A12＝−3.03485×101 A13＝−2.22038×100 A14＝ 1.08565×102 A15＝−4.90839×101 A16＝−4.99281×101 △（10）＝0.0243 △（７）＝0.00447 △（５）＝0.00104 上述した実施例4,5,6においては焦点距離Ｆを4.5mmと
し、NAを0.47、平行平板の厚さｔを0.3mmとして設計し
たものであり、略々１゜の画角範囲内において回折限界
に近い結像性能を有する。更に平行平板の厚さｔは、上
記NA,画角の条件下では±0.1mm程度の変動までは良好な
結像性能を有する。即ち、0.04F＜ｔ＜0.09Fの範囲であ
れば良好な結像性能が得られる。Example 4 F = 1 NA = 0.47 β = 0 R 1 = 0.66341 D = 0.59057 N = 1.57532 R 2 = −2.92401 W · D = 0.63075 t = 0.06664 Nt = 1.51092 A 3 = −1.79492 × 10 −3 A 4 = −2.89514 × 10 −1 A 5 = −1.07562 × 10 −2 A 6 = −8.86676 × 10 −1 A 7 = −7.28447 × 10 −2 A 8 = 1.92222 × 10 0 A 9 = −3.96149 × 10 −1 A 10 = -8.60 400 x 10 0 A 11 = 9.14741 x 10 0 A 12 = -3.21268 x 10 1 A 13 = -2.72974 x 10 0 A 14 = 1.09795 x 10 2 A 15 =-4.75359 x 10 1 A 16 =-4.27544 × 10 1 Δ (10) = 0.0247 Δ (7) = 0.00455 Δ (5) = 0.00106 Example 5 F = 1 NA = 0.47 β = 0 R 1 = 0.66640 D = 0.60087 N = 1.57532 R 2 = −2.82336 WD = 0.62656 t = 0.06664 Nt = 1.510 A 3 = −3.66687 × 10 −3 A 4 = −2.85971 × 10 −1 A 5 = 2.55345 × 10 −3 A 6 = −9.68717 × 10 −1 A 7 = 8.75908 × 10 −1 A 8 = -6.77540 x 10 -1 A 9 = -2.38760 x 10 -2 A 10 = -7.73731 x 10 0 A 11 = 1.03144 x 10 1 A 12 = -2.57036 x 10 1 A 13 = 6.94092 x 10 1 A 14 = −7.92054 × 10 1 A 15 = 4.77916 × 10 1 A 16 = −4.95151 × 10 1 Δ (10) = 0.0244 Δ (7) = 0.00451 Δ (5) = 0.00106 Example 6 F = 1 NA = 0.47 β = 0 R 1 = 0.64679 D = 0.62217 N = 1.57532 R 2 = −2.81358 WD = 0.61406 t = 0.06665 Nt = 1.510 A 3 = −2.57035 × 10 −3 A 4 = −2.82912 × 10 −1 A 5 = 6.30130 × 10 −3 A 6 = −9.43127 × 10 −1 A 7 = −5.10797 × 10 −2 A 8 = 1.90007 x 10 0 A 9 = -1.92226 x 10 -1 A 10 = -9.04979 x 10 0 A 11 = 9.13503 x 10 0 A 12 = -3.03485 x 10 1 A 13 = -2.22038 x 10 0 A 14 = 1.08565 × 10 2 A 15 = −4.90839 × 10 1 A 16 = −4.99281 × 10 1 Δ (10) = 0.0243 Δ (7) = 0.00447 Δ (5) = 0.00104 In Examples 4, 5, and 6 described above, the focal length F was 4.5 mm, the NA was 0.47, and the thickness t of the parallel plate was 0.3 mm. And has an imaging performance close to the diffraction limit within a viewing angle range of approximately 1 °. Further, the thickness t of the parallel plate has good imaging performance up to a fluctuation of about ± 0.1 mm under the above conditions of NA and angle of view. That is, in the range of 0.04F <t <0.09F, good imaging performance can be obtained.
上述した実施例4,5,6に見られるように、 の本発明の非球面単レンズにおいては上述した（１）か
ら（３）の条件に加えて、以下の条件（10）から（12）
を満足することが好ましい。As seen in Examples 4, 5, and 6 above, In the aspherical single lens according to the present invention, in addition to the above conditions (1) to (3), the following conditions (10) to (12)
Is preferably satisfied.
条件（10），（11）は３次の領域で球面収差及びコマ
収差を良好に補正するためのものである。 Conditions (10) and (11) are provided for favorably correcting spherical aberration and coma in the third order region.
条件（10）の数値範囲を外れると、特に第１面の球面
収差が大きくなり、第１面の非球面項ψ１では収差が補
正しきれなくなる。Outside the numerical range of the condition (10), in particular made spherical aberration of the first surface is large, aspheric term [psi 1 in aberration of the first surface is not completely corrected.
条件（11）は第２面でコマ収差をバランス良く補正す
るための条件であり、この数値範囲を外れると軸外の結
像性能が著しく劣化する。The condition (11) is a condition for correcting the coma aberration on the second surface in a well-balanced manner. Outside of this numerical range, the off-axis imaging performance is significantly deteriorated.
条件（12）は主に正弦条件を満足させるための条件で
ある。本発明においては軸上収差と共に一定範囲内の軸
外収差、特に、コマ収差を良好に補正しているが、条件
（12）の範囲を外れるとアイソプラナテイツクな条件が
著しく失なわれ好ましくないものである。Condition (12) is a condition for mainly satisfying the sine condition. In the present invention, off-axis aberrations within a certain range together with on-axis aberrations, particularly coma aberrations, are well corrected. However, if the range is out of the range of the condition (12), the isoplanatic condition is remarkably lost. Not something.
更に、 の本発明の非球面単レンズにおいては上述した（１）か
ら（３）及び（10）から（12）の条件に加えて、以下の
条件（13）から（15）を満足することにより、特に球面
収差を良好に補正しうるものである。Furthermore, In the aspherical single lens of the present invention, in addition to the above conditions (1) to (3) and (10) to (12), by satisfying the following conditions (13) to (15), It is possible to satisfactorily correct spherical aberration.
（13）0.02F＜△（10）＜0.03F （14）0.004F＜△（７）＜0.005F （15）０＜△（５）＜0.002F 条件式（13）〜（15）のいずれの１つの条件式にあっ
ても、その範囲の下限値を下回って、その位置における
非球面量が少ない場合には、その位置を通過する光線の
球面収差が補正不足となる。逆に条件式（13）〜（15）
のいずれの１つの条件式にあっても、その範囲の上限値
を上回った場合には、その位置を通過する光線の球面収
差が補正過剰となってくるので好ましくない。(13) 0.02F <△ (10) <0.03F (14) 0.004F <△ (7) <0.005F (15) 0 <△ (5) <0.002F Any of the conditional expressions (13) to (15) Even with one conditional expression, if the aspherical amount at the position is smaller than the lower limit of the range and the amount of aspherical surface at the position is small, the spherical aberration of the light beam passing through the position will be insufficiently corrected. Conversely, conditional expressions (13) to (15)
In any one of the conditional expressions, if the value exceeds the upper limit of the range, it is not preferable because the spherical aberration of the light beam passing through the position becomes excessively corrected.
特に好ましい条件は、 0.023F＜△（10）＜0.026F 0.0042F＜△（７）＜0.0048F 0.0009F＜△（５）＜0.0012F を同時に満足する場合であって、この時、球面収差が一
段と良好に補正可能である。A particularly preferable condition is a case where 0.023F <△ (10) <0.026F 0.0042F <△ (7) <0.0048F 0.0009F <△ (5) <0.0012F is satisfied at the same time. The correction can be made even better.
（発明の効果） 以上、本発明によれば略々0.04F〜0.111Fの厚みを有
する平行平板を介して、軸上及び軸外共に良好な収差補
正の成された非球面単レンズを提供できる。(Effects of the Invention) As described above, according to the present invention, it is possible to provide an aspherical single lens having excellent aberration correction both axially and axially through a parallel flat plate having a thickness of approximately 0.04F to 0.111F. .
光カード記録再生装置等の光メモリー装置の光ヘツド
において、対物レンズとして、或いはコリメータレンズ
として本発明に係る非球面単レンズを採用することによ
って、光ヘツドの軽量、小型化が達成可能である。By employing the aspherical single lens according to the present invention as an objective lens or a collimator lens in an optical head of an optical memory device such as an optical card recording / reproducing device, the weight and size of the optical head can be achieved.
第１図は本発明に係る非球面単レンズのレンズ断面を示
す図、第２図，第３図，第４図，第５図，第６図，第７
図は本発明に係る非球面単レンズの各実施例に於ける球
面収差、非点収差、歪曲歪収差を示す図である。 １……非球面単レンズ ２……平行平板 Ｄ……レンズ肉厚 Ｗ・Ｄ……作動距離 ｔ……平行平板の肉厚 R1,R2……第１面，第２面の曲率半径 N,Nt……屈折率FIG. 1 is a view showing a lens cross section of an aspherical single lens according to the present invention, and FIGS. 2, 3, 4, 5, 5, 6, and 7.
The figure shows spherical aberration, astigmatism, and distortion in each embodiment of the aspherical single lens according to the present invention. 1 aspherical single lens 2 parallel plate D lens thickness WD working distance t parallel plate thickness R 1 , R 2 radius of curvature of first and second surfaces N, Nt …… Refractive index
Claims (1)
ある非球面単レンズにおいて、該非球面が、該非球面の
近軸曲率をR1、該非球面上の任意の点から非球面頂点の
接平面までの距離をＸ、前記任意の点から光軸までの距
離をＨとした時に下記の式にて表わされる非球面であ
り、前記球面の曲率半径がR2であると共に次の条件
（１），（２），（３）を満足する非球面単レンズ。 ただし、Aiは非球面の非球面係数、Ｆは非球面単レンズ
の焦点距離、Ｄは非球面単レンズの光軸上肉厚、Ｎは非
球面単レンズの使用波長に対する屈折率である。1. An aspherical single lens having an aspherical surface on the object side and a spherical surface on the image side, wherein the aspherical surface has a paraxial curvature of R 1 , and an arbitrary point on the aspherical surface. X is the distance from the tangent plane to the vertex of the aspheric surface, and H is the distance from the arbitrary point to the optical axis. The aspheric surface is represented by the following equation, and the radius of curvature of the spherical surface is R 2 . And an aspheric single lens satisfying the following conditions (1), (2) and (3). Here, Ai is the aspherical coefficient of the aspherical surface, F is the focal length of the aspherical single lens, D is the thickness on the optical axis of the aspherical single lens, and N is the refractive index of the aspherical single lens with respect to the used wavelength.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63168181A JP2622155B2 (en) | 1988-07-05 | 1988-07-05 | Aspheric single lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63168181A JP2622155B2 (en) | 1988-07-05 | 1988-07-05 | Aspheric single lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0216514A JPH0216514A (en) | 1990-01-19 |
| JP2622155B2 true JP2622155B2 (en) | 1997-06-18 |
Family
ID=15863289
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63168181A Expired - Fee Related JP2622155B2 (en) | 1988-07-05 | 1988-07-05 | Aspheric single lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2622155B2 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01227115A (en) * | 1988-03-08 | 1989-09-11 | Olympus Optical Co Ltd | Small-sized large-aperture condenser lens |
-
1988
- 1988-07-05 JP JP63168181A patent/JP2622155B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0216514A (en) | 1990-01-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |