JPH0638133B2 - Projection lens - Google Patents
Projection lensInfo
- Publication number
- JPH0638133B2 JPH0638133B2 JP59132298A JP13229884A JPH0638133B2 JP H0638133 B2 JPH0638133 B2 JP H0638133B2 JP 59132298 A JP59132298 A JP 59132298A JP 13229884 A JP13229884 A JP 13229884A JP H0638133 B2 JPH0638133 B2 JP H0638133B2
- Authority
- JP
- Japan
- Prior art keywords
- lens
- power
- aberration
- image
- refractive power
- 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 - Lifetime
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Description
【発明の詳細な説明】 本発明は投影用レンズに関し、特に電子映像装置に映出
された画像をスクリーン上に拡大投影するために好適
で、温度変化による影響を受けることのない投影レンズ
に関する。The present invention relates to a projection lens, and more particularly to a projection lens suitable for enlarging and projecting an image displayed on an electronic image device on a screen and not affected by temperature change.
一般に映像表示用投影レンズではカラー映像表示用とし
て赤，青，緑の３色の単色陰極線管を用い各々の画像を
投影レンズによりスクリーン上に投影するのであるが３
色の発色特性ともスペクトル巾が比較的狭い為色消しレ
ンズである必要はない。Generally, a projection lens for image display uses a single color cathode ray tube of three colors of red, blue and green for displaying a color image, and each image is projected on the screen by the projection lens.
It is not necessary to use an achromatic lens because the spectrum width is relatively narrow in both the color development characteristics.
投影レンズとして望まれる条件として大口径及び広画角
化が挙げられる。大口径化により明るい画像を得る事が
可能となり又広画角化により短い投影距離で所望の投影
像を得る事が出来、装置全体の小型化が図れるものであ
る。Conditions desired as a projection lens include a large aperture and a wide angle of view. A large image size makes it possible to obtain a bright image, and a wide angle of view makes it possible to obtain a desired projection image at a short projection distance, thus making it possible to downsize the entire apparatus.
従来投影レンズとしては球面のみによる球面レンズや非
球面を含んだ非球面レンズが知られているが球面レンズ
では構成枚数を減らし高性能化を図る事は極めて困難で
近年は非球面を導入した非球面レンズが主流を占めてい
る。Conventionally, as a projection lens, a spherical lens with only a spherical surface or an aspherical lens including an aspherical surface is known, but it is extremely difficult to reduce the number of constituent elements and achieve high performance with a spherical lens, and in recent years, aspherical surfaces have been introduced. Spherical lenses are the mainstream.
しかしながら非球面を使用して収差補正をした投影レン
ズ自体の歴史は古く、英国特許593514が知られている。
この特許に開示された投影レンズは像面側より順に両凸
レンズと両凹レンズの貼り合わせレンズで第１面に非球
面をもち主として開口に依存する収差と軸上の色収差を
補正する第１群、スクリーン側に凸面を向けた２枚の平
凸レンズより構成された正の第２群、像画平坦化手段の
為の負の屈折力を有する第３群より構成されている。こ
の構成によると球面収差、像画彎曲、コマ収差の各収差
の内、第１群レンズにより球面収差、コマ収差、又第３
群により像面彎曲、歪曲収差を補正しているが第１群に
より補正している球面収差、コマ収差の補正は不充分で
特にコマ収差の補正が悪いものとなっている。However, the projection lens itself that has been corrected for aberrations using an aspherical surface has a long history, and British Patent 593514 is known.
The projection lens disclosed in this patent is a cemented lens of a biconvex lens and a biconcave lens in order from the image side, and has a first surface having an aspherical surface, and a first group that mainly corrects aberrations depending on the aperture and axial chromatic aberration, It is composed of a positive second lens group composed of two plano-convex lenses having a convex surface facing the screen side, and a third lens group having a negative refracting power for image flattening means. According to this configuration, among the spherical aberration, the image curvature, and the coma aberration, the first group lens causes the spherical aberration, the coma aberration, and the third aberration.
Although the field curvature and the distortion aberration are corrected by the group, the spherical aberration and the coma aberration which are corrected by the first group are insufficiently corrected, and the correction of the coma aberration is particularly bad.
更に全構成レンズがプラスチックレンズで構成されてい
るため、温度変化に伴なう特性に問題がある。これはプ
ラスチックはガラスに比べて温度変化に伴う性能のドリ
フトが１桁大きい為、レンズの置かれた雰囲気中の温度
変化による焦点位置の温度ドリフトが非常に大きく、実
用上は大きな制約になると考えられる。本発明の目的は
広画角化を図ると共に、画質特にコマ収差の補正が良好
で、温度変化による性能の悪化を生ずることのないレン
ズを提供することである。Further, since all the constituent lenses are composed of plastic lenses, there is a problem in the characteristics associated with temperature changes. This is because plastic has a one-digit larger performance drift with temperature change than glass, so the temperature drift of the focal position due to temperature change in the atmosphere in which the lens is placed is extremely large, which is considered to be a major limitation in practical use. To be An object of the present invention is to provide a lens having a wide angle of view, good correction of image quality, especially coma aberration, and free from deterioration of performance due to temperature change.
そしてこの目的を現実するため、スクリーン側から順に
正屈折力の前置レンズと、正屈折力のレンズ及びこのレ
ンズより屈折力の絶対値が小さなレンズを有する中間レ
ンズ群、そして凹なる面をスクリーン側へ向けた後置レ
ンズを具え、中間レンズ群の屈折力は前置レンズの屈折
力より大きく、前置レンズ及び中間レンズ群の屈折力の
絶対値が小さなレンズにプラスチックレンズを使用し、
中間レンズ群の正屈折力のレンズにガラスレンズを使用
する。In order to realize this purpose, a front lens having a positive refracting power, an intermediate lens group having a lens having a positive refracting power and a lens having a smaller absolute value of the refracting power than this lens, and a concave surface are formed in order from the screen side. With a rear lens facing toward the side, the refractive power of the intermediate lens group is greater than the refractive power of the front lens, and the plastic lens is used for the lens whose absolute value of the refractive power of the front lens and the intermediate lens group is small.
A glass lens is used as the lens of positive refractive power in the intermediate lens group.
第１図から第３図に示す実施例の投影レンズは、スクリ
ーン側から順に正屈折力を有するプラスチック製第１レ
ンズ（前置レンズ）、中間レンズ群として、スクリーン
側面に比して曲率半径が大で且つ凸なる面を原画像側へ
向けた正屈折力を有するガラス製第２レンズと原画像側
へ凹面を向けたプラスチック製メニスカス第３レンズ、
そして原画像側の面に比して曲率が大で且つ凹なる面を
スクリーン側へ向けたガラス製第４レンズ（後置レン
ズ）から成る。The projection lens of the embodiment shown in FIG. 1 to FIG. 3 has a plastic first lens (front lens) having positive refracting power in order from the screen side, and an intermediate lens group having a radius of curvature in comparison with the side surface of the screen. A second lens made of glass having a positive refractive power with a large and convex surface facing the original image side, and a third lens made of plastic meniscus having a concave surface facing the original image side,
Then, it is composed of a glass fourth lens (post-lens) having a concave surface facing the screen, the curvature being larger than the surface on the original image side.
続いて上述した構成による作用を述べる。Next, the operation of the above configuration will be described.
第１レンズは、主として口径に依存する収差を補正する
為に１面以上の非球面に有し、第２レンズは主として結
像の為の正の屈折力を有し、第３レンズは映像管側に凹
面を向けたメニスカスレンズで弱い正の屈折力を有し軸
上光束への収差の発生を極力抑える為コンセントリック
又はコンセントリックに近い形状とし画角に依存する収
差、軸外光束収差の補正、特にコマ収差の良好な補正を
行っており、第４レンズはスクリーン側に向けた曲率大
なる凹面により画角依存収差、特に像面彎曲、歪曲収差
の補正を果している。更にこれら軸外収差の補正を良好
なものとし半画角25°以上の広画角化を実現する為第
２，第３，第４レンズの中に少なくとも一面以上の非球
面を有し高性能化を図るものである。The first lens has one or more aspherical surfaces mainly for correcting the aberration depending on the aperture, the second lens has a positive refracting power mainly for image formation, and the third lens has a picture tube. A meniscus lens with a concave surface facing the side has a weak positive refractive power and has a concentric or near concentric shape in order to minimize the occurrence of aberrations on the axial light flux. Correction, particularly coma aberration correction, is performed, and the fourth lens corrects angle-of-view-dependent aberrations, particularly field curvature and distortion, by the concave surface with a large curvature facing the screen side. Furthermore, in order to correct these off-axis aberrations and realize a wide angle of view of a half angle of view of 25 ° or more, at least one or more aspherical surfaces are included in the second, third, and fourth lenses to achieve high performance. It is intended to
すなわち球面収差、コマ収差、像面彎曲、歪曲の内、第
１レンズにより球面収差とコマ収差、第３レンズにより
コマ収差、第４レンズにより像面彎曲、歪曲収差を補正
しており、特に第３レンズとして配したメニスカス形状
のレンズによりコマ収差を良好に補正しかつコンセント
リック又はコンセントリックに近い形状とする事により
軸上収差の発生を極力抑え、非常に高性能化を実現して
いる。That is, of spherical aberration, coma aberration, field curvature, and distortion, the first lens corrects spherical aberration and coma aberration, the third lens corrects coma aberration, and the fourth lens corrects image field curvature and distortion. The meniscus-shaped lens arranged as three lenses satisfactorily corrects coma aberration and makes it a concentric or near-concentric shape, thereby suppressing the occurrence of axial aberration as much as possible and realizing extremely high performance.
特に本例では弱い正のパワーを有する第１レンズをプラ
スチックレンズ、強い正のパワーを有する第２レンズを
ガラスレンズ、弱い正のパワーを有しメニスカスレンズ
よりなる第３レンズをプラスチックレンズ、強い負のパ
ワーを有する第４レンズをガラスレンズより構成し、特
に正負の強いパワーを有する、第２，第４レンズをガラ
スとした事によりレンズ系全体による雰囲気中温度変化
に伴なう性能変化を著しく抑制している。Particularly, in this example, the first lens having a weak positive power is a plastic lens, the second lens having a strong positive power is a glass lens, the third lens having a weak positive power is a plastic lens, and the third lens is a meniscus lens. The fourth lens having the above power is composed of a glass lens, and particularly the positive and negative powers are made of glass, and the second lens and the fourth lens are made of glass, so that the performance change due to the temperature change in the atmosphere due to the entire lens system is remarkable. It's suppressed.
更に又、本発明においては次の事項、特に下記の条件式
(2)、(3)を満足することで高度に収差を補正し得るとと
もに設計時間の短縮を図れるものである。Furthermore, in the present invention, the following matters, particularly the following conditional expression
By satisfying (2) and (3), it is possible to highly correct aberrations and shorten the design time.
(1)第３レンズのスクリーン側の面の曲率半径をＲ5（＝
Ｒs）、第３レンズの映像管側の面の曲率半径をＲ6（＝
Ｒo）とするとき、次式を満たす。(1) Let the radius of curvature of the screen side surface of the third lens be R 5 (=
R s ), the radius of curvature of the surface of the third lens on the image tube side is R 6 (=
R o ), the following equation is satisfied.
0.45＜Ｒ5／Ｒ6＜0.85 本条件は第３レンズの前面と後面の曲率半径のパワーの
分担比及びメニスカス度に関するもので下限を越えると
第３レンズのパワーが大きくなり、軸上及び軸外光束の
収差の発生量が増し主なる目的であるコマ収差の補正が
困難となってしまう。上限を越えると第３レンズのパワ
ーは非常に弱いものとなり、第２レンズのパワーの負担
が増大し第２レンズによる収差の発生量が増し、収差補
正が困難なものとなる。0.45 <R 5 / R 6 <0.85 This condition relates to the power distribution ratio of the radius of curvature of the front surface and the rear surface of the third lens and the meniscus degree. If the lower limit is exceeded, the power of the third lens will increase and The amount of aberration of the outer light flux increases, and it becomes difficult to correct coma aberration, which is the main purpose. If the upper limit is exceeded, the power of the third lens becomes extremely weak, the load of the power of the second lens increases, the amount of aberration generated by the second lens increases, and aberration correction becomes difficult.
(2)第２レンズと第３レンズから成る中間レンズ群の屈
折力をφi、全系の屈折力をφとするとき、次式を満た
す。(2) When the refractive power of the intermediate lens group consisting of the second lens and the third lens is φ i and the refractive power of the entire system is φ, the following equation is satisfied.
0.75＜φi／φ＜0.95 本条件は第２レンズと第３レンズの合成のパワーに関す
るもので、下限を越える時第１レンズによるパワーの分
担が大となり、球面収差の補正が困難となる。上限を越
える時第２レンズと第３レンズ、主に第２レンズによる
軸外収差の発生が大となり、補正を困難なものとしてく
る。0.75 <φ i /φ<0.95 This condition relates to the combined power of the second lens and the third lens, and when the lower limit is exceeded, the power share of the first lens becomes large and it becomes difficult to correct spherical aberration. When the upper limit is exceeded, off-axis aberrations are largely generated by the second lens and the third lens, mainly the second lens, which makes correction difficult.
これは例えば第２，第３レンズの正のパワーが増すと、
像面彎曲補正の為に第４レンズの負のパワーを増大させ
なければならずこれにより歪曲収差等の収差の発生を大
きなものとし高性能化を困難なものとしてくる。For example, if the positive power of the second and third lenses increases,
The negative power of the fourth lens must be increased in order to correct the field curvature, which causes the occurrence of aberrations such as distortion and the like to be large and makes it difficult to achieve high performance.
(3)望ましくは更に次の条件式を考慮するのが良く、第
１レンズと第２レンズの面間隔をＤ2とするとき、次式
を満たす。(3) It is desirable to further consider the following conditional expression, and when the surface distance between the first lens and the second lens is D 2 , the following expression is satisfied.
0.4ｆ＜Ｄ2＜0.6ｆ この条件は第１レンズと第２レンズとの間隔に関するも
ので、下限を越える時、軸外光束の結像力が不足し、第
２，第３，第４レンズの軸外光束の結像の負担量が増大
する為広画角化の大きな障害となる。上限を越える時、
軸外光束の第２レンズの後面すなわち映像管側への入射
角が大となり、軸外光束の収差の発生量が大となる。0.4f <D 2 <0.6f This condition relates to the distance between the first lens and the second lens. When the lower limit is exceeded, the image forming power of the off-axis light beam becomes insufficient, and the second, third and fourth lenses Since the burden of imaging the off-axis luminous flux increases, it becomes a big obstacle to widening the angle of view. When the upper limit is exceeded,
The angle of incidence of the off-axis light beam on the rear surface of the second lens, that is, on the image tube side is large, and the amount of aberration of the off-axis light beam is large.
以下、実施例のレンズデータを記載するが、Ｒ1，Ｒ2
…はレンズ各面の曲率半径、Ｄ1，Ｄ2…はレンズ面間の
肉厚又は空気間隔、Ｎ1，Ｎ2…は各レンズのｅ線（波長
546.1nmの光）に対する屈折率、ν1，ν2…はｅ線に対
するアッベ数である。The lens data of the examples will be described below, but R 1 , R 2
... is the radius of curvature of each lens surface, D 1 , D 2 ... is the wall thickness or air gap between the lens surfaces, N 1 , N 2 ... is the e-line (wavelength of each lens)
(Refractive index for 546.1 nm light), ν 1 , ν 2, ... Are Abbe numbers for the e-line.
非球面の形状は光軸方向をＸ軸とした直角座標において
光軸方向の変位をとするとき であらわされる対称非球面である。The shape of the aspherical surface is when the displacement in the optical axis direction is expressed in rectangular coordinates with the optical axis direction as the X axis. It is a symmetric aspherical surface.
但し Ｈ：光軸からの高さ Ｒ：頂点の曲率半径 A,B,C,D,E,Ａ′，Ｂ′，Ｃ′，Ｄ′：非球面係数 実施例１ 実施例２ 実施例３ 第１図，第２図，第３図に上記各実施例の光学配置図を
示す。各図に於いてＬ1，Ｌ2…は各レンズを、Ｓは投影
レンズと映像管との間に配された液体、Ｐは映像管の管
面ガラスをそれぞれあらわす。However, H: Height from the optical axis R: Curvature radii of vertices A, B, C, D, E, A ', B', C ', D': Aspheric coefficient Example 1 Example 2 Example 3 FIGS. 1, 2, and 3 show the optical layout of each of the above embodiments. In the drawings, L 1 , L 2 ... Represent lenses, S represents a liquid disposed between the projection lens and the picture tube, and P represents a glass surface of the picture tube.
第４図，第５図，第６図は、各実施例１〜３における各
々の収差曲線（球面収差、非点収差、横収差）である。
尚、Ｍはメリディオナル像面、Ｓはサジタル像面を示
す。FIG. 4, FIG. 5 and FIG. 6 are aberration curves (spherical aberration, astigmatism, lateral aberration) in each of Examples 1 to 3.
In addition, M represents a meridional image plane, and S represents a sagittal image plane.
以上の如く本発明によれば半画角30°以上、口径比１：
1.2以上の大口径、広画角化で優れた結像性能を有し、
温度変化の影響を受けることのない高性能の投影レンズ
を提供することができる。As described above, according to the present invention, the half angle of view is 30 ° or more and the aperture ratio is 1:
With a large aperture of 1.2 or more and a wide angle of view, it has excellent imaging performance,
It is possible to provide a high-performance projection lens that is not affected by temperature changes.
第１図，第２図，第３図は夫々本発明の実施例を示すレ
ンズ断面図。 第４図，第５図，第６図は夫々実施例の収差曲線図。 図中、Ｌ1〜Ｌ4はレンズ Ｒはレンズの曲率半径 Ｄは面間隔。1, 2, and 3 are lens cross-sectional views showing an embodiment of the present invention. FIG. 4, FIG. 5, and FIG. 6 are aberration curve diagrams of Examples, respectively. In the figure, L 1 to L 4 are lenses, R is the radius of curvature of the lens, and D is the surface spacing.
Claims (1)
影レンズに於いて、スクリーン側から順に正の屈折力の
前置レンズと、正屈折力のレンズ及びこれより屈折力の
絶対値が小さなレンズを有する中間レンズ群、そして凹
なる面をスクリーン側へ向けた後置レンズを具え前記中
間レンズ群の屈折力は前記前置レンズの屈折力より大き
く、前記前置レンズ及び中間レンズ群の屈折力の絶対値
が小さなレンズにプラスチックレンズを使用し、前記中
間レンズ群の前記正屈折力のレンズにガラスを使用する
とともに、前記中間レンズ群の屈折力をφi、全系の屈
折力をφ、前記前置レンズ群と前記中間レンズ群とのレ
ンズ面間隔をＤ2とするとき、 0.75＜φi／φ＜0.95 0.4／φ＜Ｄ2＜0.6／φ なる条件式を満足することを特徴とする投影レンズ。1. A projection lens for projecting an original image on a screen, a front lens having a positive refracting power, a lens having a positive refracting power, and an absolute value of the refracting power smaller than that in order from the screen side. An intermediate lens group having a lens and a rear lens having a concave surface facing the screen side are provided, and the refractive power of the intermediate lens group is larger than that of the front lens. A plastic lens is used for the lens having a small absolute value of force, glass is used for the lens of the positive refractive power of the intermediate lens group, the refractive power of the intermediate lens group is φ i , and the refractive power of the entire system is φ. When the lens surface distance between the front lens group and the intermediate lens group is D 2 , the conditional expression of 0.75 <φ i /φ<0.95 0.4 / φ <D 2 <0.6 / φ is satisfied. And projection lens.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59132298A JPH0638133B2 (en) | 1984-06-27 | 1984-06-27 | Projection lens |
| US06/747,029 US4682861A (en) | 1984-06-25 | 1985-06-20 | Projection lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59132298A JPH0638133B2 (en) | 1984-06-27 | 1984-06-27 | Projection lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6111717A JPS6111717A (en) | 1986-01-20 |
| JPH0638133B2 true JPH0638133B2 (en) | 1994-05-18 |
Family
ID=15078020
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59132298A Expired - Lifetime JPH0638133B2 (en) | 1984-06-25 | 1984-06-27 | Projection lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0638133B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2523106B2 (en) * | 1986-01-29 | 1996-08-07 | 株式会社日立製作所 | Optical system for projection TV |
| JP2764778B2 (en) * | 1992-10-30 | 1998-06-11 | 株式会社日立製作所 | Optical system for projection television |
| US5329363A (en) * | 1993-06-15 | 1994-07-12 | U. S. Precision Lens Incorporated | Projection lens systems having reduced spherochromatism |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58139111A (en) * | 1982-02-12 | 1983-08-18 | Minolta Camera Co Ltd | Refraction type optical system for video projector |
| JPS59198017A (en) * | 1983-04-25 | 1984-11-09 | Matsushita Electric Ind Co Ltd | Device for distributing signal into three |
-
1984
- 1984-06-27 JP JP59132298A patent/JPH0638133B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6111717A (en) | 1986-01-20 |
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