JP2001108900A - Zoom lens for projection - Google Patents
Zoom lens for projectionInfo
- Publication number
- JP2001108900A JP2001108900A JP28447999A JP28447999A JP2001108900A JP 2001108900 A JP2001108900 A JP 2001108900A JP 28447999 A JP28447999 A JP 28447999A JP 28447999 A JP28447999 A JP 28447999A JP 2001108900 A JP2001108900 A JP 2001108900A
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- Prior art keywords
- group
- zoom lens
- refractive power
- lens
- projection
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明は「平面画像を拡大
して投射結像させる投射用ズームレンズ」に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a "projection zoom lens for enlarging and projecting a planar image to project and form an image".
【０００２】[0002]
【従来の技術】液晶パネルに表示された平面画像を、ス
クリーン等の表示媒体上に拡大投射する液晶プロジェク
タは、ビデオ再生画像やコンピュータのデータ等の表示
用として、近来広く普及してきている。なかでも、赤・
緑・青の各色画像を独立した液晶パネルに表示し、各色
画像を合成して拡大投影表示する「３板式液晶プロジェ
クタ」は、画像が高精細であることから普及率も高い。
このような３板式液晶プロジェクタに使用される投射用
レンズは、最適なスクリーンサイズを容易に実現できる
ようにズーム機能を有するものが一般的である。３板式
液晶プロジェクタに用いられる投射用ズームレンズは、
以下の如き属性を持つことが好ましい。第１に、３枚の
液晶パネルにより強度変調された各色光束を、ダイクロ
イックプリズムやダイクロイックミラー等の「色合成手
段」で合成して投射用ズームレンズに入射させるので、
色合成手段を配備するための空間を確保できるように、
バックフォーカスが、焦点距離に比してなるべく長いこ
とが好ましい。第２に、低電力で明るい投射画像を表示
できるように高い光利用効率を得ることが望ましいが、
各色光束の光路合成の際、色合成手段に入射する光の角
度が画角により大きく異なると色シェーディングが発生
し易いので、光源側から投射用ズームレンズに入射する
光として、光軸に対して平行に近い光束を用いるのが良
く、平行光束を効率良く取り込めるよう、投射用ズーム
レンズは、縮小側である液晶パネル側においてテレセン
トリック性を持ち、かつ、光源からの光をなるべく多く
取り込めるように、Ｆナンバの小さい、明るいレンズで
あることが好ましい。第３に、スクリーン上で３色画像
を重ね合わせたとき、各色画像の画素が互いにずれると
良好なカラー画像を実現できず、投射画像の辺縁部に
緑、青、赤などの縁が現れて像質を損なう。このような
問題を回避できるように、倍率の色収差は、なるべく小
さく抑えられていることが好ましい。第４に、投射され
た画像の輪郭が歪んで見苦しくならないように、歪曲収
差が許容できる範囲に抑えられ、画像の忠実な再現のた
め、高いＭＴＦ・解像力を備えていることが好ましい。2. Description of the Related Art A liquid crystal projector for enlarging and projecting a flat image displayed on a liquid crystal panel onto a display medium such as a screen has recently been widely used for displaying video reproduction images, computer data, and the like. Above all, red
The “three-panel liquid crystal projector” that displays each color image of green and blue on an independent liquid crystal panel, synthesizes each color image, and displays the enlarged and projected image has a high penetration rate because the image is high definition.
A projection lens used in such a three-panel liquid crystal projector generally has a zoom function so that an optimum screen size can be easily realized. A projection zoom lens used in a three-panel liquid crystal projector is:
It is preferable to have the following attributes. First, the light fluxes of the respective colors modulated by the three liquid crystal panels are combined by a "color combining means" such as a dichroic prism or a dichroic mirror and made to enter the projection zoom lens.
In order to secure a space for deploying color synthesis means,
It is preferable that the back focus is as long as possible relative to the focal length. Second, it is desirable to obtain high light use efficiency so that a bright projection image can be displayed with low power.
At the time of the optical path synthesis of each color light beam, if the angle of the light incident on the color synthesizing means is greatly different depending on the angle of view, color shading is likely to occur, so the light incident on the zoom lens for projection from the light source side with respect to the optical axis. It is better to use a light beam that is close to parallel, so that the projection zoom lens has telecentricity on the liquid crystal panel side, which is the reduction side, and captures as much light from the light source as possible so that parallel light beams can be efficiently captured. A bright lens having a small F number is preferable. Third, when the three-color images are superimposed on the screen, a good color image cannot be realized if the pixels of each color image are shifted from each other, and edges such as green, blue, and red appear at the periphery of the projected image. Damage the image quality. In order to avoid such a problem, it is preferable that chromatic aberration of magnification is suppressed as small as possible. Fourth, it is preferable that distortion is suppressed to an allowable range so that the contour of the projected image is not distorted and unsightly, and that the image has high MTF and high resolution for faithful reproduction of the image.
【０００３】[0003]
【発明が解決しようとする課題】この発明は、上述の各
属性を良好に実現した投射用ズームレンズの提供を課題
とする。SUMMARY OF THE INVENTION It is an object of the present invention to provide a projection zoom lens which realizes the above-mentioned attributes well.
【０００４】[0004]
【課題を解決するための手段】この発明のズームレンズ
は「平面画像を拡大して投射結像させる投射用ズームレ
ンズ」である。上記平面画像は一般に液晶パネル上に表
示される画像である。この発明の投射用ズームレンズ
は、上述した３板式液晶プロジェクタ用として極めて好
適であるが、勿論、単板式液晶プロジェクタやスライド
式プロジェクタ用としても好適に使用できる。この発明
のズームレンズは、図１に例示するように、拡大側（図
の左方）から縮小側に向かって、第１群Ｇ１〜第６群Ｇ
６を配してなる。第１群Ｇ１は負の屈折力を持ち、第２
群Ｇ２、第３群Ｇ３は正の屈折力を持ち、第４群Ｇ４は
負の屈折力を持ち、第５群Ｇ５、第６群Ｇ６は正の屈折
力を持つ。したがって、全体のパワー配置は「負・正・
正・負・正・正」である。投射距離の変化に際し、平面
画像とスクリーンなどの被投射面を共役にするため、第
１群が光軸方向に移動を行う。変倍に際しては、第１群
Ｇ１、第４群Ｇ４、および第６群Ｇ６が固定され、第２
群Ｇ２、第３群Ｇ３、第５群Ｇ５が光軸方向に移動を行
う。広角端における全系の焦点距離：ｆｗ、バックフォ
ーカス（空気中での値）：ｂｆ、レンズ全長（第１群の
最も拡大側寄りの面から第６群の最も縮小側寄りの面ま
での長さ）：ＯＡＬ、第３群の焦点距離：ｆ３、第６群
を構成する凸レンズのアッべ数の平均値：ν６Ｐ、第４
群を構成する凹レンズのアッべ数の平均値：ν４Ｍ、第
５群を構成する凹レンズのアッべ数の平均値：ν５Ｍ
は、以下の条件式（１）〜（４）を満足する。 （１） ＯＡＬ＞９０・ｂｆ／ｆｗ （２） １．５＜ｆ３／ｆｗ＜２．５ （３）ν６Ｐ＞５０ （４）（ν４Ｍ＋ν５Ｍ）／２＜４０ なお、図１において、符号Ｓは絞りを表し、符号ＰＲは
色合成手段としての色合成プリズムを表す。SUMMARY OF THE INVENTION A zoom lens according to the present invention is a "zoom lens for projection for enlarging and projecting a planar image to form an image." The planar image is an image generally displayed on a liquid crystal panel. The projection zoom lens of the present invention is extremely suitable for the above-mentioned three-panel type liquid crystal projector, but can of course also be suitably used for a single-panel type liquid crystal projector or a slide type projector. As illustrated in FIG. 1, the zoom lens according to the present invention includes a first group G1 to a sixth group G from an enlargement side (left side in the figure) to a reduction side.
6 is arranged. The first group G1 has negative refractive power,
The group G2 and the third group G3 have a positive refractive power, the fourth group G4 has a negative refractive power, and the fifth group G5 and the sixth group G6 have a positive refractive power. Therefore, the overall power arrangement is “negative / positive /
Positive, negative, positive, positive ". When the projection distance changes, the first lens unit moves in the optical axis direction to make the plane image and the projection surface such as the screen conjugate. During zooming, the first group G1, the fourth group G4, and the sixth group G6 are fixed,
The group G2, the third group G3, and the fifth group G5 move in the optical axis direction. Focal length of the entire system at the wide-angle end: fw, back focus (value in air): bf, total lens length (length from the surface of the first unit closest to the enlargement side to the surface of the sixth unit closest to the reduction side) Sa): OAL, focal length of the third group: f3, average value of Abbe numbers of the convex lenses forming the sixth group: ν6P, fourth
Average value of Abbe number of concave lenses forming the group: v4M, average value of Abbe number of concave lenses forming the fifth group: v5M
Satisfies the following conditional expressions (1) to (4). (1) OAL> 90 · bf / fw (2) 1.5 <f3 / fw <2.5 (3) ν6P> 50 (4) (ν4M + ν5M) / 2 <40 In FIG. And PR denotes a color combining prism as color combining means.
【０００５】条件式（１）は、十分な結像性能を確保し
たまま、焦点距離に比して長いバックフォーカスを確保
するための条件である。長いバックフォーカスを確保す
るのに適したレンズタイプとして、負の屈折力を持つ前
群と正の屈折力を持つ後群からなる「レトロフォーカス
タイプ」が、従来から知られている。この発明の投射用
ズームレンズは、後述の実施例に示すように、全体とし
て見た場合、例えば、広角端での焦点距離：３７ｍｍ程
度に対し、バックフォーカスは３７〜４０ｍｍ程度（色
合成プリズムによる伸びを空気中での値に換算した値）
で、広角端における基本的パワー配置はレトロフォーカ
スタイプである。周知の如く、レトロフォーカスタイプ
は、負の屈折力を持つ前群と、正の屈折力を持つ後群と
で構成され、負の屈折力を持つ前群で光束を後群に向か
って発散させることにより、全系の後側主点位置を後群
よりも更に後方に設定し、焦点距離に比して長いバック
フォーカスを確保できる。従って、レトロフォーカスタ
イプにおいては、負の屈折力を持つ前群と正の屈折力を
持つ後群の間隔が大きい方がより長いバックフォーカス
の確保が容易となる。換言すれば、全系のレンズ全長が
長いほど長いバックフォーカスを確保し易い。条件式
（１）は、上記構成のレンズにおいて、焦点距離に比し
て長いバックフォーカスを確保するための条件であり、
条件式（１）の下限を超えると、３板式液晶プロジェク
タに必要な「バックフォーカスと焦点距離の比」を確保
するのに十分なレンズ全長とならず、あえて必要なバッ
クフォーカスを確保しようとすると、十分な結像性能を
得にくい。[0005] Conditional expression (1) is a condition for securing a back focus longer than the focal length while securing sufficient imaging performance. As a lens type suitable for securing a long back focus, a “retro focus type” including a front group having a negative refractive power and a rear group having a positive refractive power has been conventionally known. The projection zoom lens according to the present invention, when viewed as a whole, has, for example, a focal length at the wide angle end of about 37 mm and a back focus of about 37 to 40 mm (by a color combining prism), as shown in Examples described later. Elongation converted to a value in air)
The basic power arrangement at the wide-angle end is a retrofocus type. As is well known, the retrofocus type includes a front group having a negative refractive power and a rear group having a positive refractive power. The front group having a negative refractive power diverges a light beam toward the rear group. Thus, the rear principal point position of the entire system is set further behind the rear group, and a back focus longer than the focal length can be secured. Therefore, in the retrofocus type, the longer the distance between the front group having negative refractive power and the rear group having positive refractive power, the easier it is to secure a longer back focus. In other words, it is easier to secure a longer back focus as the overall lens length of the entire system is longer. Conditional expression (1) is a condition for securing a back focus longer than the focal length in the lens having the above-described configuration.
If the lower limit of conditional expression (1) is exceeded, the total length of the lens will not be sufficient to secure the “ratio of back focus to focal length” necessary for a three-panel liquid crystal projector, and if the intention is to secure the necessary back focus , It is difficult to obtain sufficient imaging performance.
【０００６】この発明の投射用ズームレンズでは、変倍
時における移動量は第３群が最も大きく、変倍への寄与
率は第３群が最も高い。周知の如く、変倍を行う主な群
を「バリエータ」と称している。この発明の投射用ズー
ムレンズでは第３群がバリエータである。伝統的なズー
ム形式である「拡大側から順に正の屈折力、負の屈折
力、正の屈折力、正の屈折力を配する４群ズームレン
ズ」では、例えば、特開平６−５１２０２号公報等に見
られるように、バリエータである第２群に、マスタレン
ズ群である第４群に次いで多くの枚数のレンズを用い、
変倍時の収差が大きく変化するのを抑えている。条件式
（２）は、この発明の投射用ズームレンズにおいて、バ
リエータである第３群の収差を低く抑え、かつ、レンズ
全体のコンパクト性を保ったままプロジェクタの投射用
ズームレンズとして十分な変倍比を確保するための条件
である。条件式（２）の下限を超えると、レンズ全体中
における第３群の屈折力が強くなりすぎ、第３群での諸
収差の発生量が大きくなり、変倍に伴う収差変化が大き
くなってしまう。条件式（２）の上限を超えると、プロ
ジェクタ用の投射用ズームレンズとして最低限必要と考
えられる「１．２〜１．３倍程度の変倍比」を得ること
が困難となる。また、第３群の移動量を更に大きくする
ことが必要となり、レンズ全体が大型化し、コンパクト
性が損なわれてしまう。In the projection zoom lens system according to the present invention, the amount of movement during zooming is the largest in the third lens unit, and the contribution to zooming is the highest in the third lens unit. As is well known, the main group that performs zooming is called a "variator". In the projection zoom lens of the present invention, the third group is a variator. For example, Japanese Patent Application Laid-Open No. 6-51202 discloses a traditional zoom type “a four-group zoom lens having positive refractive power, negative refractive power, positive refractive power, and positive refractive power in order from the enlargement side”. As can be seen from the above, the second group as a variator uses a large number of lenses next to the fourth group as a master lens group,
A large change in aberration at the time of zooming is suppressed. Conditional expression (2) indicates that in the projection zoom lens according to the present invention, in the projection zoom lens according to the present invention, the third lens group, which is a variator, is kept low in aberration, and the zoom ratio is sufficient for the projection zoom lens of the projector while keeping the overall lens compact. This is a condition for securing the ratio. If the lower limit of conditional expression (2) is exceeded, the refractive power of the third lens unit in the entire lens becomes too strong, the amount of various aberrations generated in the third lens unit increases, and the aberration change accompanying zooming increases. I will. If the upper limit of conditional expression (2) is exceeded, it becomes difficult to obtain a "zoom ratio of about 1.2 to 1.3 times", which is considered to be the minimum necessary for a projection zoom lens for a projector. In addition, it is necessary to further increase the amount of movement of the third lens unit, which increases the size of the entire lens and impairs compactness.
【０００７】条件式（３）は、倍率色収差を抑えるため
の条件である。倍率色収差は、軸上光線高と、軸外光線
高が高くなる面ほど発生量が大きい。この発明の投射用
ズームレンズにおいては、第６群において軸上光線高と
軸外光線高を合わせた量が、他の群に比べて特に大きく
なるため、この第６群を構成するレンズの材質を適切な
ものにする必要がある。即ち、第６群の主たる屈折力で
ある正のパワーを発生するレンズの材質の、アッべ数を
５０よりも大きい低分散な材質とすることで、倍率色収
差の発生を抑えている。条件式（４）は軸上色収差・倍
率色収差の発生を適正にし、緑色に対する赤色の色収
差、緑色に対する青色の色収差を同量程度とするための
条件で、上限を超えると、軸上色収差・倍率色収差とも
補正不足となってしまう。また、この発明の投射用ズー
ムレンズは、第４群を負の屈折力を持つ１枚のレンズの
みの構成とすることも可能であり（請求項２）、このよ
うに構成すると、よりコストメリットを大きくできる。
上記請求項１または２に記載の投射用ズームレンズは、
第１群または第２群の少なくとも１つのレンズ面を非球
面とすることができ（請求項３）、このように構成する
ことにより、諸収差の発生を小さく抑えて性能をより向
上させ、あるいはレンズ枚数を低減化して安価なレンズ
とすることができる。上記請求項１または２または３に
記載の投射用ズームレンズは、第５群または第６群の少
なくとも１つのレンズ面を非球面とすることができ（請
求項４）、このように構成することにより、諸収差の発
生を小さく抑えて性能をより向上させ、あるいはレンズ
枚数を低減化して安価なレンズとすることができる。Condition (3) is a condition for suppressing chromatic aberration of magnification. The amount of the chromatic aberration of magnification increases as the height of the on-axis ray and the height of the off-axis ray increase. In the projection zoom lens according to the present invention, since the sum of the on-axis ray height and the off-axis ray height in the sixth group is particularly large as compared with the other groups, the material of the lens constituting the sixth group Need to be appropriate. In other words, the generation of chromatic aberration of magnification is suppressed by using a low-dispersion material having an Abbe number greater than 50 as the material of the lens that generates positive power, which is the main refractive power of the sixth lens unit. Conditional expression (4) is a condition for optimizing the occurrence of axial chromatic aberration and lateral chromatic aberration, and making the amount of red chromatic aberration relative to green and the amount of blue chromatic aberration relative to green about the same amount. Both chromatic aberrations are undercorrected. In the projection zoom lens according to the present invention, the fourth group may be configured to include only one lens having a negative refractive power (claim 2). With such a configuration, a cost advantage is obtained. Can be increased.
The projection zoom lens according to claim 1 or 2,
At least one lens surface of the first group or the second group can be made aspherical (claim 3). With such a configuration, the occurrence of various aberrations is suppressed and the performance is further improved, or An inexpensive lens can be obtained by reducing the number of lenses. In the projection zoom lens according to the first, second, or third aspect, at least one lens surface of the fifth group or the sixth group may be aspherical (claim 4). Thus, the performance can be further improved by suppressing the occurrence of various aberrations, or the number of lenses can be reduced to provide an inexpensive lens.
【０００８】[0008]
【発明の実施の形態】実施の形態として具体的な実施例
を４例示す。各実施例における記号は以下の通りであ
る。拡大側から数えて第ｉ番目の面（絞りＳの面を含
む）の曲率半径を「Ｒｉ」で表す。また、拡大側から数
えて第ｉ番目の面と第ｉ＋１番目の面との軸上面間隔を
「Ｄｉ」で表す。ｉ＝０はスクリーン（被投射面）を表
し、ｉ＝ＩＭＧは液晶パネルのパネル面、即ち「平面画
像」を表す。「Ｄ０」は、スクリーンから第１レンズ面
（ｉ＝１）までの軸上距離を表す。また、拡大側から数
えてｊ番目のレンズの材質の屈折率（ｄ線に対するも
の）およびアッベ数を、それぞれ、「Ｎｊ」および「ν
ｊ」とする。また、非球面形状は、周知の式： Ｚ＝（１／Ｒｉ）・ｈ2／［１＋√｛１−（Ｋ＋１）・
(１／Ｒｉ)2・ｈ2｝］＋Ａ・ｈ4＋Ｂ・ｈ6＋Ｃ・ｈ8＋
Ｄ・ｈ10＋・・ で表す。この式において、Ｚ：光軸方向の座標、ｈ：光
軸直交方向の座標、Ｒｉ：軸上曲率半径、Ｋ：円錐定
数、Ａ，Ｂ，Ｃ，Ｄ．．：高次の係数であり、これらの
数値を与えることにより非球面の形状を特定する。計算
基準波長は「５４６．１ｎｍ」である。DESCRIPTION OF THE PREFERRED EMBODIMENTS Four specific examples are shown as embodiments. The symbols in each embodiment are as follows. The radius of curvature of the i-th surface (including the surface of the stop S) counted from the enlargement side is represented by “Ri”. The distance between the i-th surface and the (i + 1) -th surface counted from the enlargement side is represented by “Di”. i = 0 represents a screen (projected surface), and i = IMG represents a panel surface of a liquid crystal panel, that is, a “flat image”. “D0” represents an axial distance from the screen to the first lens surface (i = 1). Also, the refractive index (for the d-line) and the Abbe number of the material of the j-th lens counted from the magnification side are denoted by “Nj” and “ν”, respectively.
j ”. In addition, the aspherical surface shape can be calculated by a known formula: Z = (1 / Ri) · h 2 / [1 + √ ｛1− (K + 1) ·
(1 / Ri) 2 · h 2}] + A · h 4 + B · h 6 + C · h 8 +
D · h 10 + ··· In this equation, Z: coordinates in the optical axis direction, h: coordinates in the optical axis orthogonal direction, Ri: on-axis radius of curvature, K: conical constant, A, B, C, D. . : Higher-order coefficients, which specify the shape of the aspherical surface by giving these numerical values. The calculation reference wavelength is “546.1 nm”.
【０００９】[0009]
【実施例】 実施例１ ｉ Ｒｉ Ｄｉ ｊ Ｎｊ νｊ 0: ∞ 2900.000 1: 138.500 4.399 １ 1.83400 37.3 2: -313.001 0.200 3: 103.576 1.800 ２ 1.48749 70.4 4: 29.367 8.783 5: -52.613 1.800 ３ 1.48749 70.4 6: 35.191 可変 7: 47.773 4.653 ４ 1.78590 43.9 8: -402.667 可変 9: 68.386 6.525 ５ 1.72916 54.7 10: -39.202 1.800 ６ 1.80518 25.5 11: -152.595 8.065 12: （絞り）∞ 可変 13: -155.226 2.495 ７ 1.48749 70.4 14: -55.203 6.646 15: -28.902 1.800 ８ 1.74330 49.2 16: 76.960 可変 17: -113.647 8.789 ９ 1.69680 55.5 18: -24.282 1.800 10 1.84666 23.8 19: -37.607 可変 20: 1061.514 5.842 11 1.62041 60.3 21: -72.197 0.200 22: 60.363 8.014 12 1.62041 60.3 23: -309.035 0.000 24: ∞ 36.000 13 1.51680 64.2 25: ∞ 17.000 IMG: ∞ 0.000 第２４面は色合成プリズムの射出面、第２５面は色合成プリズムの入射面であ る。 可変量 焦点距離 37.736 43.000 49.005 Ｄ６ 10.098 8.969 8.131 Ｄ８ 9.285 5.118 1.000 Ｄ１２ 1.005 6.301 11.257 Ｄ１６ 10.500 7.902 4.761 Ｄ１９ 0.500 3.098 6.240 条件式（１）の値 ｂｆ／ｆw＝１．０８，ＯＡＬ＝１０５ 条件式（２）の値 ｆ３／ｆw＝１．９２ 条件式（３）の値 ６０．３ 条件式（４）の値 ３６．５ 図２に、実施例１の投射用ズームレンズの、広角端にお
ける断面図（上図）、望遠端における断面図（下図）と
変倍に伴う各群の変位を示す。図３に実施例１の広角端
における縦収差図、図４に同望遠端における縦収差図
を、図５に実施例１の広角端における横収差図、図６に
同望遠端における横収差図を示す。Example 1 Example 1 i Ri Dij Nj νj 0: ∞ 2900.000 1: 138.500 4.399 1 1.83400 37.3 2: -313.001 0.200 3: 103.576 1.800 2 1.48749 70.4 4: 29.367 8.783 5: -52.613 1.800 3 1.48749 70.4 6: 35.191 Variable 7: 47.773 4.653 4 1.78590 43.9 8: -402.667 Variable 9: 68.386 6.525 5 1.72916 54.7 10: -39.202 1.800 6 1.80518 25.5 11: -152.595 8.065 12: (Aperture) ∞ Variable 13: -155.226 2.495 7 1.48749 70.4 14 : -55.203 6.646 15: -28.902 1.800 8 1.74330 49.2 16: 76.960 Variable 17: -113.647 8.789 9 1.69680 55.5 18: -24.282 1.800 10 1.84666 23.8 19: -37.607 Variable 20: 1061.514 5.842 11 1.62041 60.3 21: -72.197 0.200 22 : 60.363 8.014 12 1.62041 60.3 23: -309.035 0.000 24: ∞ 36.000 13 1.51680 64.2 25: ∞ 17.000 IMG: ∞ 0.000 The 24th surface is the exit surface of the color combining prism, and the 25th surface is the entrance surface of the color combining prism . Variable amount Focal length 37.736 43.000 49.005 D6 10.098 8.969 8.131 D8 9.285 5.118 1.000 D12 1.005 6.301 11.257 D16 10.500 7.902 4.761 D19 0.500 3.098 6.240 Value of conditional expression (1) bf / fw = 1.08, OAL = 105 Conditional expression (2) Value f3 / fw = 1.92 Value of Conditional Expression (3) 60.3 Value of Conditional Expression (4) 36.5 FIG. 2 is a sectional view of the projection zoom lens of Example 1 at the wide-angle end (top). Figure), a cross-sectional view at the telephoto end (lower figure) and the displacement of each group due to zooming. FIG. 3 is a longitudinal aberration diagram of the first embodiment at the wide-angle end, FIG. 4 is a longitudinal aberration diagram of the same telephoto end, FIG. 5 is a lateral aberration diagram of the first embodiment at the wide-angle end, and FIG. Is shown.
【００１０】 実施例２ ｉ Ｒｉ Ｄｉ ｊ Ｎｊ νｊ 0: ∞ 2900.000 1: 81.953 5.902 1 1.69680 55.5 2: -639.935 0.200 3: 90.077 2.200 2 1.48749 70.4 4: 23.620 11.312 5: -41.200 1.800 3 1.48749 70.4 6: 36.684 可変 7: 44.966(＊) 0.050 4 1.50706 53.4 8: 41.815 5.770 5 1.83400 37.3 9: -206.553 可変 10: 74.336 6.041 6 1.72916 54.7 11: -35.476 1.800 7 1.80518 25.5 12: -127.907 6.528 13: （絞り）∞ 7.882 14: -68.099 1.943 8 1.48749 70.4 15: -51.283 可変 16: -26.289 1.500 9 1.67270 32.2 17: 71.019 可変 18: -142.043 6.831 10 1.48749 70.4 19: -24.537 1.450 20: -21.666 2.100 11 1.64769 33.8 21: -29.916 可変 22: 3811.136 8.832 12 1.62041 60.3 23: -41.082 0.200 24: 62.588 7.766 13 1.62041 60.3 25: -302.785 5.000 26: ∞ 36.000 14 1.51680 64.2 27: ∞ 12.000 IMG: ∞ 0.000 第２６面は色合成プリズムの射出面、第２７面は色合成プリズムの入射面であ る。 (＊)は「ガラスの球面レンズ上に薄いプラスチックを成型してなるハイブリッ ドタイプの非球面」であり、非球面係数は以下のとおりである。 K ＝-0.177950 ， A＝0.132372E-05， B=-0.101380E-08 ， C=-0.280747E-12 ， D=0.0 可変量 焦点距離 37.769 43.075 49.131 Ｄ６ 6.053 4.312 3.417 Ｄ９ 10.695 5.769 1.000 Ｄ１５ 2.192 8.860 14.524 Ｄ１７ 4.950 4.614 2.762 Ｄ２１ 1.000 1.336 3.188 条件式（１）の値 ｂｆ／ｆw＝１．０８，ＯＡＬ＝１０５ 条件式（２）の値 ｆ３／ｆw＝１．７１ 条件式（３）の値 ６０．３ 条件式（４）の値 ３３．０ 図７に、実施例２の投射用ズームレンズの、広角端にお
ける断面図（上図）、望遠端における断面図（下図）と
変倍に伴う各群の変位を示す。図８に実施例２の広角端
における縦収差図、図９に同望遠端における縦収差図
を、図１０に実施例２の広角端における横収差図、図１
１に同望遠端における横収差図を示す。Example 2 i Ri Dij Nj νj 0: ∞ 2900.000 1: 81.953 5.902 1 1.69680 55.5 2: -639.935 0.200 3: 90.077 2.200 2 1.48749 70.4 4: 23.620 11.312 5: -41.200 1.800 3 1.48749 70.4 6: 36.684 Variable 7: 44.966 (*) 0.050 4 1.50706 53.4 8: 41.815 5.770 5 1.83400 37.3 9: -206.553 Variable 10: 74.336 6.041 6 1.72916 54.7 11: -35.476 1.800 7 1.80518 25.5 12: -127.907 6.528 13: (Aperture) ∞ 7.882 14: -68.099 1.943 8 1.48749 70.4 15: -51.283 Variable 16: -26.289 1.500 9 1.67270 32.2 17: 71.019 Variable 18: -142.043 6.831 10 1.48749 70.4 19: -24.537 1.450 20: -21.666 2.100 11 1.64769 33.8 21: -29.916 Variable 22: 3811.136 8.832 12 1.62041 60.3 23: -41.082 0.200 24: 62.588 7.766 13 1.62041 60.3 25: -302.785 5.000 26: ∞ 36.000 14 1.51680 64.2 27: ∞ 12.000 IMG: ∞ 0.000 The 26th surface is the exit surface of the color synthesis prism The 27th surface is the entrance surface of the color combining prism. (*) Is “a hybrid type aspherical surface formed by molding thin plastic on a glass spherical lens”. The aspherical surface coefficients are as follows. K = -0.177950, A = 0.132372E-05, B = -0.101380E-08, C = -0.280747E-12, D = 0.0 Variable focal length 37.769 43.075 49.131 D6 6.053 4.312 3.417 D9 10.695 5.769 1.000 D15 2.192 8.860 14.524 D17 4.950 4.614 2.762 D21 1.000 1.336 3.188 Value of conditional expression (1) bf / fw = 1.08, OAL = 105 Value of conditional expression (2) f3 / fw = 1.71 Value of conditional expression (3) 60.3 Value of Conditional Expression (4) 33.0 FIG. 7 shows a cross-sectional view of the projection zoom lens according to the second embodiment at the wide-angle end (upper view), a cross-sectional view at the telephoto end (lower view), and the magnification of each group. Indicates displacement. FIG. 8 is a longitudinal aberration diagram at the wide-angle end of the second embodiment, FIG. 9 is a longitudinal aberration diagram at the telephoto end, FIG. 10 is a lateral aberration diagram at the wide-angle end of the second embodiment, and FIG.
FIG. 1 shows a lateral aberration diagram at the telephoto end.
【００１１】 実施例３ ｉ Ｒｉ Ｄｉ ｊ Ｎｊ νｊ 0: ∞ 2900.000 1: 135.017 2.200 1 1.48749 70.4 2: 39.336 7.357 3: -97.771 1.800 2 1.48749 70.4 4: 37.953 可変 5: 50.494（＊１） 0.050 3 1.50706 53.4 6: 45.920 6.721 4 1.83400 37.3 7: -220.200 可変 8: 70.529 5.665 5 1.83500 43.0 9: -45.890 1.800 6 1.84666 23.8 10: 5121.912 13.456 11: （絞り）∞ 可変 12: -22.227 1.800 7 1.67270 32.2 13: 142.677 可変 14: -212.995 7.183 8 1.62041 60.3 15: -27.352 2.200 9 1.75520 27.5 16: -42.673 0.100 10 1.50706 53.4 17: -39.603（＊２） 可変 18: -419.796 11.0773 11 1.63854 55.5 19: -33.598 0.200 20: 59.980 7.149 12 1.62041 60.3 21: 3427.810 5.000 22: ∞ 36.000 13 1.51680 64.2 23: ∞ 12.000 IMG: ∞ 0.000 第２２面は色合成プリズムの射出面、第２３面は色合成プリズムの入射面であ る。 （＊１）は「ガラスの球面レンズ上に薄いプラスチックを成型してなるハイブ リッドタイプの非球面」であり、非球面係数は以下のとおりである。 K ＝ -0.747183 ， A＝0.194418E-05 ， B＝-0.107331E-09 ， C＝0.470872E-12 ， D＝0.0 （＊２）は「ガラスの球面レンズ上に薄いプラスチックを成型してなるハイブ リッドタイプの非球面」であり、非球面係数は以下のとおりである。 K＝-0.664682 ， A＝0.189322E-05 ，B＝0.311321E-08 ，C＝0.143023E-11 ， D＝-0.765210E-15 可変量 焦点距離 37.748 43.070 49.162 Ｄ４ 5.304 4.244 3.679 Ｄ７ 14.139 6.919 0.200 Ｄ１１ 12.298 20.578 27.862 Ｄ１３ 4.000 3.122 1.579 Ｄ１７ 0.500 1.378 2.921 条件式（１）の値 ｂｆ／ｆｗ＝１．０８，ＯＡＬ＝１０５ 条件式（２）の値 ｆ３／ｆｗ＝２．３２ 条件式（３）の値 ５７．９ 条件式（４）の値 ２９．９ 図１２に、実施例３の投射用ズームレンズの、広角端に
おける断面図（上図）、望遠端における断面図（下図）
と、変倍に伴う各群の変位を示す。図１３に実施例３の
広角端における縦収差図、図１４に同望遠端における縦
収差図を、図１５に実施例３の広角端における横収差
図、図１６に同望遠端における横収差図を示す。Example 3 i Ri Di Nj vj 0: ∞ 2900.000 1: 135.017 2.200 1 1.48749 70.4 2: 39.336 7.357 3: -97.771 1.800 2 1.48749 70.4 4: 37.953 Variable 5: 50.494 (* 1) 0.050 3 1.50706 53.4 6: 45.920 6.721 4 1.83400 37.3 7: -220.200 Variable 8: 70.529 5.665 5 1.83500 43.0 9: -45.890 1.800 6 1.84666 23.8 10: 5121.912 13.456 11: (Aperture) ∞ Variable 12: -22.227 1.800 7 1.67270 32.2 13: 142.677 Variable 14: -212.995 7.183 8 1.62041 60.3 15: -27.352 2.200 9 1.75520 27.5 16: -42.673 0.100 10 1.50706 53.4 17: -39.603 (* 2) Variable 18: -419.796 11.0773 11 1.63854 55.5 19: -33.598 0.200 20: 59.980 7.149 12 1.62041 60.3 21: 3427.810 5.000 22: ∞ 36.000 13 1.51680 64.2 23: ∞ 12.000 IMG: ∞ 0.000 The 22nd surface is the exit surface of the color combining prism, and the 23rd surface is the entrance surface of the color combining prism. (* 1) is a "hybrid type aspherical surface formed by molding a thin plastic on a glass spherical lens", and the aspherical surface coefficient is as follows. K = -0.747183, A = 0.194418E-05, B = -0.107331E-09, C = 0.470872E-12, D = 0.0 (* 2) is a hive made by molding thin plastic on a glass spherical lens. A lid-type aspherical surface ", and the aspherical surface coefficients are as follows. K = -0.664682, A = 0.189322E-05, B = 0.311321E-08, C = 0.143023E-11, D = -0.765210E-15 Variable focal length 37.748 43.070 49.162 D4 5.304 4.244 3.679 D7 14.139 6.919 0.200 D11 12.298 20.578 27.862 D13 4.000 3.122 1.579 D17 0.500 1.378 2.921 Value of conditional expression (1) bf / fw = 1.08, OAL = 105 Value of conditional expression (2) f3 / fw = 2.32 Value of conditional expression (3) 57 2.9 Value of Conditional Expression (4) 29.9 FIG. 12 is a cross-sectional view of the projection zoom lens according to the third embodiment at the wide-angle end (upper view), and a cross-sectional view at the telephoto end (lower view).
And the displacement of each group due to zooming. FIG. 13 is a longitudinal aberration diagram at the wide angle end of the third embodiment, FIG. 14 is a longitudinal aberration diagram at the telephoto end, FIG. 15 is a lateral aberration diagram at the wide angle end of the third embodiment, and FIG. Is shown.
【００１２】 実施例４ ｉ Ｒｉ Ｄｉ ｊ Ｎｊ νｊ 0: ∞ 2900.000 1: 83.206 1.800 1 1.48749 70.4 2: 35.512（＊） 7.352 3: -64.582 1.800 2 1.48749 70.4 4: 34.057 可変 5: 44.554 6.615 3 1.83400 37.3 6: -124.264 可変 7: 47.782 6.104 4 1.83500 43.0 8: -44.749 1.800 5 1.84666 23.8 9: 168.164 5.102 10:（絞り） ∞ 可変 11: -28.805 1.500 6 1.62588 35.7 12: 85.694 9.900 13: -1250.100 6.448 7 1.48749 70.4 14: -27.624 2.100 8 1.72825 28.3 15: -42.891 1.000 16: -964.105 6.136 9 1.62041 60.3 17: -47.153（＊２）0.200 18: 61.232 7.352 10 1.62041 60.3 19: -215.715 5.000 20: ∞ 36.000 11 1.51680 64.2 21: ∞ 9.000 IMG: ∞ 0.000 第２０面は色合成プリズムの射出面、第２１面は色合成プリズムの入射面であ る。Example 4 i Ri Dij Nj νj 0: ∞ 2900.000 1: 83.206 1.800 1 1.48749 70.4 2: 35.512 (*) 7.352 3: -64.582 1.800 2 1.48749 70.4 4: 34.057 Variable 5: 44.554 6.615 3 1.83400 37.3 6 : -124.264 Variable 7: 47.782 6.104 4 1.83500 43.0 8: -44.749 1.800 5 1.84666 23.8 9: 168.164 5.102 10: (Aperture) ∞ Variable 11: -28.805 1.500 6 1.62588 35.7 12: 85.694 9.900 13: -1250.100 6.448 7 1.48749 70.4 14: -27.624 2.100 8 1.72825 28.3 15: -42.891 1.000 16: -964.105 6.136 9 1.62041 60.3 17: -47.153 (* 2) 0.200 18: 61.232 7.352 10 1.62041 60.3 19: -215.715 5.000 20: ∞ 36.000 11 1.51680 64.2 21 : ∞ 9.000 IMG: ∞ 0.000 The 20th surface is the exit surface of the color combining prism, and the 21st surface is the entrance surface of the color combining prism.
【００１３】 （＊１）は非球面であり、非球面係数は以下のとおりである。 K＝-0.340530 ， A＝-0.219750E-05，B＝-0.217723E-09，C＝-0.704716E-11， D＝0.376357E-14 （＊２）は非球面であり、非球面係数は以下のとおりである。 K＝-0.457725 ， A＝0.135333E-05，B＝-0.172321E-08，C＝0.506214E-11， D＝-0.409838E-14 可変量 焦点距離 37.620 42.872 48.866 Ｄ４ 5.655 4.571 3.750 Ｄ６ 9.609 5.229 1.000 Ｄ１０ 9.528 14.991 20.041 Ｄ１２ 9.900 6.417 2.048 Ｄ１５ 1.000 4.483 8.852 条件式（１）の値 ｂｆ／ｆｗ＝１．００，ＯＡＬ＝９０．０ 条件式（２）の値 ｆ３／ｆｗ＝２．１２ 条件式（３）の値 ６０．３ 条件式（４）の値 ３２．０ 図１７に、実施例４の投射用ズームレンズの、広角端に
おける断面図（上図）、望遠端における断面図（下図）
と、変倍に伴う各群の変位を示す。図１８に実施例４の
広角端における縦収差図、図１９に同望遠端における縦
収差図を、図２０に実施例４の広角端における横収差
図、図２１に同望遠端における横収差図を示す。(* 1) is an aspherical surface, and the aspherical surface coefficient is as follows. K = -0.340530, A = -0.219750E-05, B = -0.217723E-09, C = -0.704716E-11, D = 0.376357E-14 (* 2) is an aspheric surface, and the aspheric coefficient is as follows: It is as follows. K = -0.457725, A = 0.135333E-05, B = -0.172321E-08, C = 0.506214E-11, D = -0.409838E-14 Variable focal length 37.620 42.872 48.866 D4 5.655 4.571 3.750 D6 9.609 5.229 1.000 D10 9.528 14.991 20.041 D12 9.900 6.417 2.048 D15 1.000 4.483 8.852 Value of conditional expression (1) bf / fw = 1.00, OAL = 90.0 Value of conditional expression (2) f3 / fw = 2.12 Conditional expression (3) 60.3 Value of conditional expression (4) 32.0 FIG. 17 is a cross-sectional view of the projection zoom lens of Example 4 at the wide-angle end (upper view), and a cross-sectional view at the telephoto end (lower view).
And the displacement of each group due to zooming. 18 is a longitudinal aberration diagram at the wide-angle end of Example 4, FIG. 19 is a longitudinal aberration diagram at the telephoto end, FIG. 20 is a lateral aberration diagram at the wide-angle end of Example 4, and FIG. 21 is a lateral aberration diagram at the telephoto end. Is shown.
【００１４】各「レンズ断面図」において、符号Ｓは絞
りを示し、符号ＰＲは色合成プリズムを示す。絞りＳ
は、いずれの実施例においても、ズーミングに際して、
第３群と一体に移動する。各収差図において、「Ｇ」は
波長５４６．１ｎｍでの収差、「Ｒ」は波長６１０．０
ｎｍでの収差、「Ｂ」は波長４６０．０ｎｍでの収差を
意味し、「Y」は像高、「Ｆ」はＦナンバ、「Ｓ」は波
長５４６．１ｎｍでのサジタル像面、「Ｔ」は波長５４
６．１ｎｍでのタンジェンシャル像面を意味する。な
お、各収差は、スクリーン側を物体側、液晶パネル側を
像側として算出されたものであり、従って、像高：Yは
液晶パネル上のものである。In each “lens sectional view”, reference symbol S indicates a stop, and reference symbol PR indicates a color combining prism. Aperture S
In any of the embodiments, when zooming,
It moves together with the third group. In each aberration diagram, “G” indicates aberration at a wavelength of 546.1 nm, and “R” indicates a wavelength of 610.0 nm.
The aberration at nm, “B” means the aberration at a wavelength of 460.0 nm, “Y” is the image height, “F” is the F number, “S” is the sagittal image surface at the wavelength 546.1 nm, “T Is the wavelength 54
6.1 means tangential image plane at 1 nm. Note that each aberration is calculated with the screen side being the object side and the liquid crystal panel side being the image side. Therefore, the image height: Y is on the liquid crystal panel.
【００１５】上記実施例１〜４の投射用ズームレンズ
は、平面画像を拡大して投射結像させる投射用ズームレ
ンズであって、拡大側から順に、第１Ｇ１〜第６群Ｇ６
を配してなり、第１群Ｇ１は負の屈折力、第２群Ｇ２は
正の屈折力、第３群Ｇ３は正の屈折力、第４群Ｇ４は負
の屈折力、第５群Ｇ５は正の屈折力、第６群Ｇ６は正の
屈折力を各々有し、投射距離の変化に際し、平面画像と
被投射面を共役にするため、第１群Ｇ１が光軸方向への
移動を行い、変倍に際しては、第１群Ｇ１、第４群Ｇ
４、第６群Ｇ６が固定で、第２群Ｇ２、第３群Ｇ３、第
５群Ｇ５が光軸方向への移動を行い、広角端における全
系の焦点距離：ｆＷ、バックフォーカス（空気中での
値）：ｂｆ、レンズ全長（第１群の最も拡大側寄りの面
から第６群の最も縮小側寄りの面までの長さ）：ＯＡ
Ｌ、第３群の焦点距離：ｆ３、第６群を構成する凸レン
ズのアッべ数の平均値：Ν６Ｐ、第４群を構成する凹レ
ンズのアッべ数の平均値：Ν４Ｍ、第５群を構成する凹
レンズのアッべ数の平均値：Ν５Ｍが、 （１）ＯＡＬ＞９０・ｂｆ／ｆｗ （２）１．５＜ｆ３／ｆｗ＜２．５ （３）ν６Ｐ＞５０ （４）（ν４Ｍ＋ν５Ｍ）／２＜４０ なる条件式を満足する（請求項１）。The projection zoom lenses of the first to fourth embodiments are projection zoom lenses for projecting and forming an image by enlarging a planar image. The first to sixth groups G6 are arranged in order from the enlargement side.
The first group G1 has a negative refractive power, the second group G2 has a positive refractive power, the third group G3 has a positive refractive power, the fourth group G4 has a negative refractive power, and the fifth group G5. Denotes a positive refractive power, and the sixth unit G6 has a positive refractive power. When the projection distance is changed, the first unit G1 moves in the optical axis direction in order to conjugate the plane image and the projection surface. For zooming, the first group G1, the fourth group G
4, the sixth group G6 is fixed, the second group G2, the third group G3, and the fifth group G5 move in the optical axis direction, and the focal length of the entire system at the wide-angle end: fW, back focus (in air) ): Bf, total lens length (length from the surface of the first unit closest to the enlargement side to the surface of the sixth unit closest to the reduction side): OA
L, focal length of the third group: f3, average value of Abbe number of the convex lens constituting the sixth group: Ν6P, average value of Abbe number of the concave lens constituting the fourth group: Ν4M, constituting the fifth group The average value of the Abbe number of the concave lens: 5M is (1) OAL> 90 · bf / fw (2) 1.5 <f3 / fw <2.5 (3) ν6P> 50 (4) (ν4M + ν5M) / The conditional expression 2 <40 is satisfied (claim 1).
【００１６】また実施例３、４の投射用ズームレンズ
は、第４群Ｇ４が、負の屈折力を持つ単レンズのみで構
成され（請求項２）、実施例２の投射用ズームレンズ
は、第１群Ｇ１または第２群Ｇ２中の少なくとも１つの
面を非球面とし（請求項３）、実施例３，４の投射用ズ
ームレンズは、第１群Ｇ１または第２群Ｇ２中の少なく
とも１つの面を非球面とし、且つ、第５群Ｇ５または第
６群Ｇ６中の少なくとも１つの面を非球面としている
（請求項４）。In the projection zoom lenses of the third and fourth embodiments, the fourth group G4 is composed of only a single lens having a negative refractive power (claim 2). At least one surface in the first group G1 or the second group G2 is aspherical (Claim 3), and the projection zoom lens according to the third or fourth embodiment includes at least one surface in the first group G1 or the second group G2. One surface is an aspheric surface, and at least one surface in the fifth group G5 or the sixth group G6 is an aspheric surface.
【００１７】[0017]
【発明の効果】以上に説明したように、この発明によれ
ば新規な投射用ズームレンズを実現できる。この発明の
投射用ズームレンズは、上記各実施例に関する収差図に
示されたように広角側・望遠側ともに性能が良好であ
り、特に３板式液晶プロジェクタ用に好適である。As described above, according to the present invention, a novel projection zoom lens can be realized. The projection zoom lens according to the present invention has good performance on both the wide-angle side and the telephoto side as shown in the aberration diagrams for the above embodiments, and is particularly suitable for a three-panel liquid crystal projector.
【図１】この発明の投射用ズームレンズのレンズ構成を
示す断面図である。FIG. 1 is a sectional view showing a lens configuration of a projection zoom lens according to the present invention.
【図２】実施例１の投射用ズームレンズの広角端におけ
る断面図（上図）、望遠端における断面図（下図）と変
倍に伴う各群の変位を示す図である。FIGS. 2A and 2B are a cross-sectional view (upper view) at the wide-angle end and a cross-sectional view at the telephoto end (lower view) of the projection zoom lens according to the first embodiment, and a diagram illustrating displacement of each unit due to zooming.
【図３】実施例１の広角端における縦収差図である。FIG. 3 is a longitudinal aberration diagram at a wide angle end according to the first embodiment.
【図４】実施例１の望遠端における縦収差図である。FIG. 4 is a longitudinal aberration diagram at a telephoto end in Example 1.
【図５】実施例１の広角端における横収差図である。FIG. 5 is a lateral aberration diagram at a wide angle end according to the first embodiment.
【図６】実施例１の望遠端における横収差図である。FIG. 6 is a lateral aberration diagram at the telephoto end according to the first embodiment.
【図７】実施例２の投射用ズームレンズの広角端におけ
る断面図（上図）、望遠端における断面図（下図）と変
倍に伴う各群の変位を示す図である。7A and 7B are a cross-sectional view (upper view) at the wide-angle end and a cross-sectional view at the telephoto end (lower view) of the projection zoom lens according to the second embodiment, and a diagram illustrating displacement of each unit due to zooming.
【図８】実施例２の広角端における縦収差図である。FIG. 8 is a longitudinal aberration diagram at the wide angle end according to the second embodiment.
【図９】実施例２の望遠端における縦収差図である。FIG. 9 is a longitudinal aberration diagram at a telephoto end in Example 2.
【図１０】実施例２の広角端における横収差図である。FIG. 10 is a lateral aberration diagram at a wide angle end according to the second embodiment.
【図１１】実施例２の望遠端における横収差図である。FIG. 11 is a lateral aberration diagram at a telephoto end in Example 2.
【図１２】実施例３の投射用ズームレンズの広角端にお
ける断面図（上図）、望遠端における断面図（下図）と
変倍に伴う各群の変位を示す図である。12A and 12B are a cross-sectional view (upper view) at the wide-angle end and a cross-sectional view at the telephoto end (lower view) of the projection zoom lens according to the third embodiment, and a diagram illustrating displacement of each unit due to zooming.
【図１３】実施例３の広角端における縦収差図である。FIG. 13 is a longitudinal aberration diagram at the wide angle end according to the third embodiment.
【図１４】実施例３の望遠端における縦収差図である。FIG. 14 is a longitudinal aberration diagram at a telephoto end in Example 3.
【図１５】実施例３の広角端における横収差図である。FIG. 15 is a lateral aberration diagram at a wide angle end according to the third embodiment.
【図１６】実施例３の望遠端における横収差図である。FIG. 16 is a lateral aberration diagram at a telephoto end in Example 3.
【図１７】実施例４の投射用ズームレンズの広角端にお
ける断面図（上図）、望遠端における断面図（下図）と
変倍に伴う各群の変位を示す図である。17A and 17B are a cross-sectional view (upper view) at the wide-angle end and a cross-sectional view at the telephoto end (lower view) of the projection zoom lens according to the fourth embodiment, and a diagram illustrating displacement of each unit due to zooming.
【図１８】実施例４の広角端における縦収差図である。FIG. 18 is a longitudinal aberration diagram at the wide angle end according to the fourth embodiment.
【図１９】実施例４の望遠端における縦収差図である。FIG. 19 is a longitudinal aberration diagram at the telephoto end in Example 4.
【図２０】実施例４の広角端における横収差図である。FIG. 20 is a lateral aberration diagram at a wide-angle end in Example 4.
【図２１】実施例４の望遠端における横収差図である。FIG. 21 is a lateral aberration diagram at a telephoto end in Example 4.
Ｇ１ 第１群 Ｇ２ 第２群 Ｇ３ 第３群 Ｇ４ 第４群 Ｇ５ 第５群 Ｇ６ 第６群 ＰＲ 色合成プリズム Ｓ 絞り G1 First group G2 Second group G3 Third group G4 Fourth group G5 Fifth group G6 Sixth group PR Color synthesis prism S Aperture
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 2H087 KA06 PA08 PA10 PA11 PA19 PA20 PB10 PB12 PB13 QA02 QA06 QA07 QA14 QA17 QA22 QA25 QA26 QA32 QA34 QA41 QA45 QA46 RA05 RA12 RA13 RA32 RA36 SA57 UA01 9A001 BB06 HH23 KK16 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H087 KA06 PA08 PA10 PA11 PA19 PA20 PB10 PB12 PB13 QA02 QA06 QA07 QA14 QA17 QA22 QA25 QA26 QA32 QA34 QA41 QA45 QA46 RA05 RA12 RA13 RA32 RA36 SA57 UA01 9A001 KK
Claims (4)
ズームレンズであって、 拡大側から順に、第１〜第６群を配してなり、第１群は
負の屈折力、第２群は正の屈折力、第３群は正の屈折
力、第４群は負の屈折力、第５群は正の屈折力、第６群
は正の屈折力を各々有し、 投射距離の変化に際し、平面画像と被投射面を共役にす
るため、第１群が光軸方向への移動を行い、 変倍に際しては、第１群、第４群、第６群が固定で、第
２群、第３群、第５群が光軸方向への移動を行い、 広角端における全系の焦点距離：ｆｗ、バックフォーカ
ス（空気中での値）：ｂｆ、レンズ全長（第１群の最も
拡大側寄りの面から第６群の最も縮小側寄りの面までの
長さ）：ＯＡＬ、第３群の焦点距離：ｆ３、第６群を構
成する凸レンズのアッべ数の平均値：ν６Ｐ、第４群を
構成する凹レンズのアッべ数の平均値：ν４Ｍ、第５群
を構成する凹レンズのアッべ数の平均値：ν５Ｍが、 （１）ＯＡＬ＞９０・ｂｆ／ｆｗ （２）１．５＜ｆ３／ｆｗ＜２．５ （３）ν６Ｐ＞５０ （４）（ν４Ｍ＋ν５Ｍ）／２＜４０ なる条件式を満足することを特徴とする投射用ズームレ
ンズ。1. A projection zoom lens for projecting and forming a planar image by enlarging a plane image, comprising a first group to a sixth group arranged in order from an enlargement side, wherein the first group has a negative refractive power, The second group has a positive refractive power, the third group has a positive refractive power, the fourth group has a negative refractive power, the fifth group has a positive refractive power, and the sixth group has a positive refractive power. The first unit moves in the direction of the optical axis in order to make the plane image and the projection surface conjugate at the time of the change, and at the time of zooming, the first, fourth and sixth units are fixed, and The second, third, and fifth units move in the optical axis direction. The focal length of the entire system at the wide-angle end: fw, the back focus (value in air): bf, the total length of the lens (the first unit) Length from the surface closest to the enlargement side to the surface closest to the reduction side of the sixth unit): OAL, focal length of the third unit: f3, average value of Abbe number of the convex lens forming the sixth unit: ν6P, the average value of Abbe numbers of the concave lenses forming the fourth group: ν4M, and the average value of Abbe numbers of the concave lenses forming the fifth group: ν5M are as follows: (1) OAL> 90 · bf / fw (2) 1.5 <f3 / fw <2.5 (3) ν6P> 50 (4) (ν4M + ν5M) / 2 <40 The zoom lens for projection characterized by satisfying the following conditional expression.
て、 第４群が、負の屈折力を持つ単レンズのみで構成される
ことを特徴とする投射用ズームレンズ。2. The projection zoom lens according to claim 1, wherein the fourth lens unit includes only a single lens having a negative refractive power.
ズにおいて、 第１群または第２群中の、少なくとも１つの面を非球面
とすることを特徴とする投射用ズームレンズ。3. The projection zoom lens according to claim 1, wherein at least one of the first and second groups has an aspherical surface.
ームレンズにおいて、 第５群または第６群中の、少なくとも１つの面を非球面
とすることを特徴とする投射用ズームレンズ。4. The projection zoom lens according to claim 1, wherein at least one surface of the fifth group or the sixth group has an aspherical surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28447999A JP4451516B2 (en) | 1999-10-05 | 1999-10-05 | Projection zoom lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28447999A JP4451516B2 (en) | 1999-10-05 | 1999-10-05 | Projection zoom lens |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| JP2001108900A true JP2001108900A (en) | 2001-04-20 |
| JP2001108900A5 JP2001108900A5 (en) | 2006-11-24 |
| JP4451516B2 JP4451516B2 (en) | 2010-04-14 |
Family
ID=17679062
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28447999A Expired - Fee Related JP4451516B2 (en) | 1999-10-05 | 1999-10-05 | Projection zoom lens |
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| Country | Link |
|---|---|
| JP (1) | JP4451516B2 (en) |
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| US6785055B2 (en) | 2001-05-23 | 2004-08-31 | Minolta Co. Ltd. | Zoom lens system |
| US6989939B2 (en) | 2003-08-11 | 2006-01-24 | Canon Kabushiki Kaisha | Variable-power optical system, projection optical system, and image projection apparatus using the systems |
| US7016118B2 (en) | 2003-08-11 | 2006-03-21 | Canon Kabushiki Kaisha | Zoom lens and image projection apparatus having the same |
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| CN100368856C (en) * | 2004-09-17 | 2008-02-13 | 佳能株式会社 | Zoom lens and image projection apparatus including the same |
| US7079324B2 (en) | 2004-09-17 | 2006-07-18 | Canon Kabushiki Kaisha | Zoom lens and image projection apparatus including the same |
| US9285574B2 (en) | 2014-02-04 | 2016-03-15 | Konica Minolta, Inc. | Variable magnification projection optical system and image projection apparatus |
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