JP2010072374A - Projection optical system - Google Patents

Projection optical system Download PDF

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JP2010072374A
JP2010072374A JP2008240199A JP2008240199A JP2010072374A JP 2010072374 A JP2010072374 A JP 2010072374A JP 2008240199 A JP2008240199 A JP 2008240199A JP 2008240199 A JP2008240199 A JP 2008240199A JP 2010072374 A JP2010072374 A JP 2010072374A
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free
form surface
lens
coaxial
optical system
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Masahiko Tanitsu
雅彦 谷津
Koji Hirata
浩二 平田
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Hitachi Ltd
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Hitachi Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an oblique projection type projection optical system which suppresses an increase in the effective size of a free-form surface lens that is used for focus adjustment by specifying a moving direction of the free-form surface lens. <P>SOLUTION: The projection optical system comprises, in order from an enlargement side, a free-form surface mirror which is rotationally asymmetric, a free-form surface lens system which is rotationally asymmetric, and a coaxial lens system which is rotationally symmetric, and obliquely projects image light to an image surface as a whole, wherein the free-form surface lens is moved in an advancing direction of luminous flux or moved in a direction different from an optical axis direction of the coaxial lens system. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、液晶等の映像表示素子を使用して、スクリーン等の像面上に映像を投影する投射装置用の投射光学系を提供する技術に関するものである。   The present invention relates to a technique for providing a projection optical system for a projection apparatus that projects an image on an image plane such as a screen using an image display element such as a liquid crystal.

反射鏡を用いたミラー方式の投射型表示装置において、反射鏡４枚構成の中の第三反射鏡を光軸方向に移動させることでフォーカス調整を行う技術が、特許文献１に開示されている。   Patent Document 1 discloses a technique for performing focus adjustment by moving a third reflecting mirror in the four reflecting mirror configuration in the optical axis direction in a mirror-type projection display device using a reflecting mirror. .

また、特許文献２において、拡大側から自由曲面ミラーと自由曲面レンズと回転対称レンズで構成された斜投射方式の投射光学系が開示されている。   Further, Patent Document 2 discloses a projection optical system of an oblique projection system that includes a free-form surface mirror, a free-form surface lens, and a rotationally symmetric lens from the enlargement side.

特開２００６−２９３０１７号公報JP 2006-293017 A 特開２００７−３２２８１１号公報JP 2007-322811 A

投射光学系におけるフォーカス調整方式としては、拡大側でレンズ径の大きい前玉レンズを移動させる前玉フォーカス方式と、途中のレンズを移動させるリアフォーカス方式の２つの方式がある。   As a focus adjustment method in the projection optical system, there are two methods: a front lens focus method in which a front lens having a large lens diameter is moved on the enlargement side, and a rear focus method in which a lens in the middle is moved.

前玉フォーカス方式では、前玉レンズの焦点距離ｆと、至近距離Ｌを用いて、前玉レンズの繰り出し量δは、δ＝ｆ2／（Ｌ−ｆ）で求まるので、至近距離Ｌが小さくなると、繰り出し量δは急激に大きくなる。その分、前玉レンズを大きくする必要が生じるが、特に、広角レンズのように、前玉レンズの径が大きい投射光学系においては、大きな問題となる。 In the front lens focus method, since the focal length f of the front lens and the close distance L are used, the extension amount δ of the front lens is obtained by δ = f 2 / (L−f), and therefore the close distance L is small. Then, the feed amount δ increases rapidly. Accordingly, it is necessary to increase the size of the front lens. However, particularly in a projection optical system having a large diameter of the front lens, such as a wide-angle lens, it becomes a serious problem.

一方、リアフォーカス方式では、レンズが移動する為の空間を確保する必要性があるが、レンズ径の一番大きな前玉レンズを固定にできるので、投射光学系全体の大型化の防止には効果的である。   On the other hand, with the rear focus method, it is necessary to secure a space for the lens to move, but the front lens with the largest lens diameter can be fixed, which is effective in preventing the overall projection optical system from becoming large. Is.

特許文献１においてはフォーカス調整についての詳細な記述が無いが、特許文献１は大きさが小さい途中の第三反射鏡３２をフォーカス調整（表３）に使用しており、即ち、リアフォーカス方式について開示されている。   Although there is no detailed description about focus adjustment in Patent Document 1, Patent Document 1 uses a third reflecting mirror 32 in the middle of a small size for focus adjustment (Table 3), that is, a rear focus method. It is disclosed.

しかしながら、従来のフォーカス調整と同様に、特許文献１においても、フォーカス素子（レンズやミラー）を光軸方向へ移動させており、この点において、小型化のための改善の余地が残されている。   However, similarly to the conventional focus adjustment, in Patent Document 1, the focus element (lens or mirror) is moved in the optical axis direction, and in this respect, there remains room for improvement for miniaturization. .

また、特許文献２においても、フォーカス調整として、自由曲面レンズを回転対称レンズの光軸方向に移動させている。   Also in Patent Document 2, as a focus adjustment, the free-form surface lens is moved in the optical axis direction of the rotationally symmetric lens.

以下、図３から図６を用いて、フォーカス素子を光軸方向に移動させる場合の問題点について説明する。   Hereinafter, a problem in the case where the focus element is moved in the optical axis direction will be described with reference to FIGS.

図３は、投射型表示装置から像面までの距離を短くするために、投射光学系から像面へ斜めに投射する斜投射方式の投射型表示装置の使用形態を表す図である。投射光学系１０を内蔵する投射型表示装置２０をテーブル４０の上に設置し、すぐ側の壁面５０に像面３０を斜めに投射している。斜投射方式を採用することで、投射光学系１０から像面３０の中央点までの距離を一定のままで、投射型表示装置２０から像面３０までの図３での水平方向の距離を短くした投射が可能となる。   FIG. 3 is a diagram illustrating a usage form of an oblique projection type projection display apparatus that projects obliquely from the projection optical system to the image plane in order to shorten the distance from the projection display apparatus to the image plane. A projection display device 20 incorporating the projection optical system 10 is installed on a table 40, and the image plane 30 is projected obliquely onto the wall surface 50 on the immediate side. By adopting the oblique projection method, the distance from the projection optical system 10 to the center point of the image plane 30 remains constant, and the horizontal distance in FIG. 3 from the projection display device 20 to the image plane 30 is shortened. Projection is possible.

しかしながら、従来の投射光学系を単純に斜めから投射しただけでは、ビルを下から見上げた時と同様に、台形状の歪を有する所謂キーストーン状の映像となってしまう。そこで、本出願人らは、特許文献２において、回転非対称なエラー量に対しては、回転非対称な自由曲面レンズや自由曲面ミラーを用いることで、この台形歪を補正した投射光学系について出願している。   However, simply projecting a conventional projection optical system from an oblique angle results in a so-called keystone-like image having a trapezoidal distortion, as in the case of looking up at a building from below. Therefore, the applicants have applied for a projection optical system in Patent Document 2 that corrects this trapezoidal distortion by using a rotationally asymmetric free-form lens or a free-form mirror for a rotationally asymmetric error amount. ing.

図４は、自由曲面レンズと自由曲面ミラーを含む投射光学系１０の光線図である。レンズＬ１〜レンズＬ８からなる回転対称な同軸レンズ系３と、自由曲面レンズＬ９〜Ｌ１０からなる回転非対称な自由曲面レンズ系４と、回転非対称な自由曲面ミラー５で、構成した投射光学系１０により、映像表示素子１の像を像面３０に斜めに投射している。なお、フィルタ２は、色合成手段としてのクロスプリズムや映像表示素子１のカバーガラスや、偏光板等々の厚みを総合して考慮し、説明上記載した光学的に等価な換算フィルタである。   FIG. 4 is a ray diagram of the projection optical system 10 including a free-form surface lens and a free-form surface mirror. A projection optical system 10 comprising a rotationally symmetric coaxial lens system 3 composed of lenses L1 to L8, a rotationally asymmetric freeform lens system 4 composed of freeform curved lenses L9 to L10, and a rotationally asymmetric freeform surface mirror 5. The image of the video display element 1 is projected obliquely on the image plane 30. The filter 2 is an optically equivalent conversion filter described in the description in consideration of the thicknesses of the cross prism as the color synthesizing unit, the cover glass of the image display element 1, the polarizing plate, and the like.

この図４において、同軸系レンズ３の光軸と同じ方向に、自由曲面レンズ系４を移動させることで、投射距離に対するフォーカス調整を行っている。図５は、自由曲面レンズ系４の繰り出し状態を詳細に示すために、投射サイズ６０インチ、８０インチ、１００インチでのレンズＬ８と自由曲面レンズ系４の位置を表した図である。６０インチ〜１００インチで、特に、自由曲面レンズＬ１０が、１００インチに比べて６０インチの方が大きく繰り出していることが分かる。   In FIG. 4, focus adjustment with respect to the projection distance is performed by moving the free-form surface lens system 4 in the same direction as the optical axis of the coaxial lens 3. FIG. 5 is a diagram showing the positions of the lens L8 and the free-form surface lens system 4 at projection sizes of 60 inches, 80 inches, and 100 inches, in order to show the extended state of the free-form surface lens system 4 in detail. From 60 inches to 100 inches, in particular, it can be seen that the free-form surface lens L10 is extended more greatly at 60 inches than at 100 inches.

図５の自由曲面レンズＬ１０に着目すると、自由曲面レンズＬ１０がレンズＬ８に近い側、即ち、投射サイズ１００インチのときには、自由曲面レンズＬ１０の上側に光束が通過しない領域が存在していることが分かる。   Focusing on the free-form surface lens L10 in FIG. 5, when the free-form surface lens L10 is close to the lens L8, that is, when the projection size is 100 inches, there is an area where the light beam does not pass above the free-form surface lens L10. I understand.

そこで、フォーカス調整の移動方向と、光束の進行方向で単純化した光学モデル図である図６を用いて、自由曲面レンズＬ１０の大きさについて説明する。   Accordingly, the size of the free-form surface lens L10 will be described with reference to FIG. 6 which is an optical model diagram simplified in the moving direction of the focus adjustment and the traveling direction of the light flux.

図６の水平方向が同軸レンズ系３の光軸方向であり、自由曲面レンズ系４をこの光軸方向に移動させることでフォーカス調整を行っている。ところで、斜投射方式においては、自由曲面レンズ系４を通過する光束は、図６において右上方向（斜め方向）に進行する。ここで、遠距離側で必要な自由曲面レンズＬ１０の有効サイズを基準に考えると、近距離側では点Ａ側でサイズが不足しており、一方、反対側の点Ｂ側では逆に、サイズが余っていることが分かる。即ち、近距離側での光束サイズ以上の有効サイズが、自由曲面レンズＬ１０に必要となっている。   The horizontal direction in FIG. 6 is the optical axis direction of the coaxial lens system 3, and focus adjustment is performed by moving the free-form surface lens system 4 in the optical axis direction. By the way, in the oblique projection method, the light beam passing through the free-form surface lens system 4 travels in the upper right direction (oblique direction) in FIG. Here, considering the effective size of the free-form surface lens L10 required on the far side as a reference, the size is insufficient on the point A side on the near side, while the size is opposite on the point B side on the opposite side. It turns out that there is a surplus. In other words, the free-form lens L10 needs an effective size that is equal to or larger than the light beam size on the short distance side.

ところで、回転対称レンズの場合は対象物を回転させながら切削バイトを１方向に移動させることで形状加工できるのに対して、自由曲面レンズの場合は切削バイトを２次元状に移動させた形状加工が必要となる。同様に、回転対称レンズの場合は１軸方向に測定プローブを移動させることで形状測定ができるのに対して、自由曲面レンズの場合は測定プローブを２次元状に移動させた形状測定が必要となる。   By the way, in the case of a rotationally symmetric lens, shape processing can be performed by moving the cutting tool in one direction while rotating the object, whereas in the case of a free-form surface lens, shape processing by moving the cutting tool in two dimensions. Is required. Similarly, in the case of a rotationally symmetric lens, shape measurement can be performed by moving the measurement probe in one axial direction, whereas in the case of a free-form surface lens, shape measurement is required in which the measurement probe is moved two-dimensionally. Become.

即ち、自由曲面レンズは回転対称レンズに比べて、多くの形状加工時間と形状測定時間が必要となるので、自由曲面レンズの有効サイズは極力小さいことが望ましい。   That is, a free-form surface lens requires a lot of shape processing time and shape measurement time as compared with a rotationally symmetric lens, so it is desirable that the effective size of the free-form surface lens is as small as possible.

本発明は、上記の事情の鑑み、自由曲面レンズを用いた斜投射方式において、自由曲面レンズを小型化した投射光学系を提供することを目的とする。   In view of the above circumstances, an object of the present invention is to provide a projection optical system in which a free-form surface lens is miniaturized in an oblique projection system using a free-form surface lens.

上記の目的を達成するために、本発明は、拡大側から順に、回転非対称な自由曲面ミラーと、回転非対称な自由曲面レンズ系と、回転対称な同軸レンズ系で構成され、全体として像面へ映像光を斜めに投射する投射光学系において、自由曲面レンズを光束の進行方向に沿って移動させる。或いは、同軸レンズ系の光軸方向と異なる方向に移動させる。   In order to achieve the above object, the present invention comprises, in order from the magnification side, a rotationally asymmetric free-form surface mirror, a rotationally asymmetric free-form surface lens system, and a rotationally symmetric coaxial lens system. In a projection optical system that projects image light obliquely, a free-form surface lens is moved along the traveling direction of a light beam. Alternatively, it is moved in a direction different from the optical axis direction of the coaxial lens system.

また、上記について、以下に別の表現にて、説明する。   Further, the above will be described in another expression below.

映像表示素子からの光束を通す回転対称な同軸系レンズと、前記同軸系レンズからの光束を通す回転非対称な自由曲面を有する自由曲面レンズと、前記自由曲面レンズからの光束を反射する回転非対称な自由曲面を有する自由曲面ミラーと、前記自由曲面ミラーからの光束を被投射面に投射する投射光学系において、前記自由曲面レンズを前記同軸系レンズの光軸の平行方向へ移動するとともに、前記同軸系レンズの光軸の平行方向とは異なる方向へ移動することで投射距離に応じた合焦動作を行うようにする。   A rotationally symmetric coaxial lens that passes a light beam from an image display element, a free-form surface lens having a rotationally asymmetric free-form surface that passes a light beam from the coaxial lens, and a rotationally asymmetrical surface that reflects the light beam from the free-form surface lens In a free-form surface mirror having a free-form surface and a projection optical system that projects a light beam from the free-form surface mirror onto a projection surface, the free-form surface lens is moved in a direction parallel to the optical axis of the coaxial lens, and the coaxial The focusing operation according to the projection distance is performed by moving in a direction different from the parallel direction of the optical axis of the system lens.

また、映像表示素子からの光束を通す回転対称な同軸系レンズと、前記同軸系レンズからの光束を通す回転非対称な自由曲面を有する自由曲面レンズと、前記自由曲面レンズからの光束を反射する回転非対称な自由曲面を有する自由曲面ミラーと、前記自由曲面ミラーからの光束を被投射面に投射する投射光学系において、前記自由曲面レンズを前記同軸系レンズの光軸の平行方向と、前記同軸系レンズの光軸の平行方向とは異なる方向とで合成された方向へ移動することで投射距離に応じた合焦動作を行うようにする。   In addition, a rotationally symmetric coaxial lens that passes the light flux from the image display element, a free-form surface lens having a rotationally asymmetric free-form surface that passes the light flux from the coaxial lens, and a rotation that reflects the light flux from the free-form surface lens A free-form surface mirror having an asymmetric free-form surface, and a projection optical system that projects a light beam from the free-form surface mirror onto a projection surface, wherein the free-form surface lens is parallel to the optical axis of the coaxial lens and the coaxial system By moving in a direction synthesized with a direction different from the parallel direction of the optical axis of the lens, a focusing operation corresponding to the projection distance is performed.

また、合焦動作の際に、前記同軸系レンズからの光束の通る範囲が前記自由曲面レンズの範囲よりも大きくなる場合には、前記同軸系レンズからの周辺部の光束で前記自由曲面レンズを通らない範囲の大きさを等しくなる傾向となるように前記自由曲面レンズを移動することで投射距離に応じた合焦動作を行うようにする。   Further, when the range of the light beam from the coaxial lens becomes larger than the range of the free-form surface lens during the focusing operation, the free-form surface lens is By moving the free-form surface lens so that the size of the range that does not pass tends to be equal, a focusing operation corresponding to the projection distance is performed.

また、合焦動作の際に、前記同軸系レンズからの光束の通る範囲が前記自由曲面レンズの範囲よりも小さくなる場合には、前記自由曲面レンズの周辺において、前記同軸系レンズからの光束の通らない範囲の大きさを等しくなる傾向となるように前記自由曲面レンズを移動することで投射距離に応じた合焦動作を行うようにする。   Further, in the focusing operation, if the range through which the light beam from the coaxial lens passes is smaller than the range of the free-form surface lens, the light beam from the coaxial lens is around the free-form surface lens. By moving the free-form surface lens so that the size of the range that does not pass tends to be equal, a focusing operation corresponding to the projection distance is performed.

上記構成とすることで、自由曲面レンズを小型化できるので、自由曲面レンズの形状加工時間・形状測定時間の短縮化が可能な投射光学系を提供できる。   With the above configuration, the free-form surface lens can be reduced in size, so that it is possible to provide a projection optical system capable of shortening the shape processing time and the shape measurement time of the free-form surface lens.

本発明によれば、従来よりも形状加工時間・形状測定時間の短縮化が可能な投射光学系を提供できるものとなる。   According to the present invention, it is possible to provide a projection optical system capable of shortening the shape processing time and the shape measurement time as compared with the prior art.

以下、図面を用いて、本発明の実施例を説明する。   Embodiments of the present invention will be described below with reference to the drawings.

先ず、本発明の実施例について、自由曲面レンズ系４を含む投射光学系１０の光線図を図１に、フォーカス調整時の自由曲面レンズＬ１０の移動と光束範囲の関係を表す模式図を図２に示す。   First, in the embodiment of the present invention, a ray diagram of the projection optical system 10 including the free-form surface lens system 4 is shown in FIG. 1, and a schematic diagram showing the relationship between the movement of the free-form surface lens L10 and the light flux range during focus adjustment is shown in FIG. Shown in

図１は、拡大側から順に、回転非対称な自由曲面ミラー５と、回転非対称レンズで構成された自由曲面レンズ系４と、回転対称レンズで構成された同軸レンズ系３で構成された投射光学系１０によって、映像表示素子１の像を像面へ斜に拡大投射している。なお、フィルタ２は、色合成手段としてのクロスプリズムや映像表示素子１のカバーガラスや、偏光板等々の厚みを総合して考慮し、説明上記載した光学的に等価な換算フィルタである。   FIG. 1 shows a projection optical system composed of a rotationally asymmetric free-form surface mirror 5, a free-form surface lens system 4 composed of a rotationally asymmetric lens, and a coaxial lens system 3 composed of a rotationally symmetric lens in order from the magnification side. 10, the image of the video display element 1 is enlarged and projected obliquely onto the image plane. The filter 2 is an optically equivalent conversion filter described in the description in consideration of the thicknesses of the cross prism as the color synthesizing unit, the cover glass of the image display element 1, the polarizing plate, and the like.

本発明の実施例においては、フォーカス調整のために自由曲面レンズ系４を、光束の進行方向に沿った方向、即ち、同軸レンズ系３の光軸とは異なる方向に移動することで、投射サイズ（投射距離）に応じたフォーカス調整を行っている。   In the embodiment of the present invention, the free-form surface lens system 4 is moved in the direction along the traveling direction of the light beam, that is, the direction different from the optical axis of the coaxial lens system 3 for focus adjustment, thereby adjusting the projection size. Focus adjustment according to (projection distance) is performed.

このフォーカス調整の移動方向と、光束の進行方向で単純化した光学モデル図である図２を用いて、本発明の実施例における自由曲面レンズＬ１０の大きさについて説明する。   The size of the free-form surface lens L10 in the embodiment of the present invention will be described with reference to FIG. 2 which is an optical model diagram simplified in the moving direction of the focus adjustment and the traveling direction of the light beam.

図２の水平方向が同軸レンズ系３の光軸方向であり、自由曲面レンズ系４をこの光軸方向とは異なる方向、即ち、光束の進行方向に沿った方向に移動させることでフォーカス調整を行っている。斜投射方式においては、自由曲面レンズ系４を通過する光束は、図２において右上方向（斜め方向）に進行するので、図６と同様に、遠距離側で必要な自由曲面レンズＬ１０の有効サイズを基準に考えると、近距離側では点Ａ側と点Ｂ側でもサイズが不足しているが、図６の点Ｂ側のようにサイズが余っている箇所がないので、図２の自由曲面レンズＬ１０は、図６の自由曲面レンズＬ１０よりも有効サイズが小さくできた。   The horizontal direction of FIG. 2 is the optical axis direction of the coaxial lens system 3, and the focus adjustment is performed by moving the free-form surface lens system 4 in a direction different from the optical axis direction, that is, a direction along the traveling direction of the light beam. Is going. In the oblique projection method, the light beam passing through the free-form surface lens system 4 travels in the upper right direction (oblique direction) in FIG. 2, so that the effective size of the free-form surface lens L10 required on the far side is the same as in FIG. As a reference, the short distance side has insufficient size on the point A side and the point B side, but there is no surplus size like the point B side in FIG. The effective size of the lens L10 can be made smaller than that of the free-form surface lens L10 of FIG.

上記自由曲面レンズ系４のフォーカス調整について、他の表現を以下に追記する。   Regarding the focus adjustment of the free-form surface lens system 4, other expressions will be added below.

図２に例示するように、フォーカス調整を遠距離側から近距離側に対して行うには、自由曲面レンズ系４を像面３０に近づけるように同軸レンズ系３の光軸方向に沿って移動しつつ、同軸レンズ系３からの外周側光束が自由曲面レンズ系４の端部を通る範囲を等しくなる傾向となるように自由曲面レンズ系４を移動するようにする。   As illustrated in FIG. 2, in order to perform focus adjustment from the long distance side to the short distance side, the free-form surface lens system 4 is moved along the optical axis direction of the coaxial lens system 3 so as to be close to the image plane 30. However, the free-form surface lens system 4 is moved so that the outer peripheral side light flux from the coaxial lens system 3 tends to be equal in the range passing through the end of the free-form surface lens system 4.

更に別の表現を行うと、自由曲面レンズ系４を同軸レンズ系３の光軸方向への平行移動に加えて、同軸レンズ系３の光軸方向とは異なる方向への移動するようにする。   In other words, the free-form surface lens system 4 is moved in a direction different from the optical axis direction of the coaxial lens system 3 in addition to the parallel movement of the coaxial lens system 3 in the optical axis direction.

このような２方向への移動を合成した方向へ移動することで、単純な同軸レンズ系３の光軸方向への平行移動の場合に比べて、図６の点Ｂ側のようにサイズが余っている箇所を低減することが可能となる。   By moving in the direction in which the movements in these two directions are combined, the size of the coaxial lens system 3 is larger as shown on the point B side in FIG. It is possible to reduce the number of locations.

この図６の点Ｂ側のようにサイズが余っている箇所を低減するとは、合焦動作においては、自由曲面レンズＬ１０の位置によって、同軸レンズ系３からの光束の範囲と自由曲面レンズＬ１０の大きさの範囲の関係が変わることが有り、具体的には、以下の２つの場合をも想定するものである。   In FIG. 6, the reduction of the excessive portion such as the point B side means that in the focusing operation, depending on the position of the free-form surface lens L10, the range of the light flux from the coaxial lens system 3 and the free-form surface lens L10. The relationship between the size ranges may change. Specifically, the following two cases are assumed.

先ず第１の場合は、図２に例示するように、同軸レンズ系３からの光束の範囲が自由曲面レンズＬ１０よりも大きい場合である。この場合は、図２の斜線で示すＡ点、Ｂ点の光束を通せない範囲の面積が出来るだけ等しくなる傾向となるように、自由曲面レンズＬ１０を同軸レンズ系３の光軸方向とは異なる方向へ、加えて移動するようにする。   First, as illustrated in FIG. 2, the first case is a case where the range of the light flux from the coaxial lens system 3 is larger than that of the free-form surface lens L10. In this case, the free-form surface lens L10 is different from the optical axis direction of the coaxial lens system 3 so that the areas in the range where the light fluxes at the points A and B indicated by diagonal lines in FIG. In addition to move in the direction.

次に第２の場合は、図２に例示していないが、同軸レンズ系３からの光束の範囲が自由曲面レンズＬ１０よりも小さい場合である。この場合は、上記第１の場合とは逆に、図２の斜線で示すＡ点、Ｂ点の範囲は、レンズがあるのに光束の範囲の方が小さい為に、同軸レンズ系３からの光束が来ない範囲と読み替えることとなる。   Next, the second case is not illustrated in FIG. 2, but the range of the light flux from the coaxial lens system 3 is smaller than the free-form surface lens L10. In this case, contrary to the first case, the range of the points A and B indicated by oblique lines in FIG. It will be read as the range where the luminous flux does not come.

この第２の場合は、同軸レンズ系３からの光束が来ないＡ点、Ｂ点の範囲の面積が出来るだけ等しくなる傾向となるように、自由曲面レンズＬ１０を同軸レンズ系３の光軸方向とは異なる方向へ、加えて移動するようにする。   In this second case, the free-form surface lens L10 is arranged in the optical axis direction of the coaxial lens system 3 so that the areas of the points A and B where the light beam from the coaxial lens system 3 does not come tend to be as equal as possible. And move in a different direction.

また、上述のフォーカス調整において、「自由曲面レンズ系４を同軸レンズ系３の光軸方向への平行移動に加えて、同軸レンズ系３の光軸方向とは異なる方向への移動するようにする」については、自由曲面レンズ系４を同軸レンズ系３の光軸方向への平行移動と、同軸レンズ系３の光軸方向とは異なる方向への移動を別々に行うものであっても良い。若しくは、自由曲面レンズ系４を前記同軸レンズ系３の光軸の平行方向と、前記同軸レンズ系３の光軸の平行方向とは異なる方向とで合成された方向へ移動するようにするものであっても良い。   In the focus adjustment described above, “the free-form surface lens system 4 is moved in a direction different from the optical axis direction of the coaxial lens system 3 in addition to the parallel movement of the coaxial lens system 3 in the optical axis direction. ", The parallel movement of the free-form surface lens system 4 in the optical axis direction of the coaxial lens system 3 and the movement in a direction different from the optical axis direction of the coaxial lens system 3 may be performed separately. Alternatively, the free-form surface lens system 4 is moved in a direction synthesized by a parallel direction of the optical axis of the coaxial lens system 3 and a direction different from the parallel direction of the optical axis of the coaxial lens system 3. There may be.

その結果、上記第１の場合、そして第２の場合であっても、図６の自由曲面レンズＬ１０よりも有効サイズが小さくすることを可能とするものである。   As a result, even in the first case and the second case, the effective size can be made smaller than that of the free-form surface lens L10 of FIG.

上述したように、金型の形状加工及び形状測定において多くの時間を要する自由曲面レンズの有効サイズを小さくする投射光学系を提供できる。   As described above, it is possible to provide a projection optical system that reduces the effective size of a free-form surface lens that requires a lot of time in mold shape processing and shape measurement.

本発明の実施例の投射光学系のフォーカス調整についての説明図である。It is explanatory drawing about the focus adjustment of the projection optical system of the Example of this invention. 本発明の実施例の合焦レンズの大きさに関する説明図である。It is explanatory drawing regarding the magnitude | size of the focusing lens of the Example of this invention. 斜投射方式の投射型表示装置の使用形態図である。It is a usage pattern figure of the projection type display apparatus of an oblique projection system. 従来の投射光学系のフォーカス調整の説明図である。It is explanatory drawing of the focus adjustment of the conventional projection optical system. フォーカスレンズの繰り出し量の例を表す図である。It is a figure showing the example of the drawing amount of a focus lens. 従来のフォーカスレンズの大きさに関する説明図である。It is explanatory drawing regarding the magnitude | size of the conventional focus lens.

符号の説明Explanation of symbols

１…映像表示素子、２…フィルタ、３…回転対称な同軸レンズ系、４…回転非対称な自由曲面レンズ系、５…回転非対称な自由曲面ミラー、１０…投射光学系、２０…投射型表示装置、３０…像面、４０…テーブル、５０…壁面。 DESCRIPTION OF SYMBOLS 1 ... Image display element, 2 ... Filter, 3 ... Rotationally symmetric coaxial lens system, 4 ... Rotationally asymmetric free curved surface lens system, 5 ... Rotationally asymmetric free curved surface mirror, 10 ... Projection optical system, 20 ... Projection type display apparatus 30 ... image plane, 40 ... table, 50 ... wall surface.

Claims (6)

映像表示素子からの光束を通す回転対称な同軸系レンズと、
前記同軸系レンズからの光束を通す回転非対称な自由曲面を有する自由曲面レンズと、
前記自由曲面レンズからの光束を反射する回転非対称な自由曲面を有する自由曲面ミラーと、
を有し、
前記自由曲面ミラーからの光束を被投射面に投射する投射光学系において、
前記自由曲面レンズを前記同軸系レンズの光軸の平行方向へ移動するとともに、前記同軸系レンズの光軸の平行方向とは異なる方向へ移動することで投射距離に応じた合焦動作を行うことを特徴とする投射光学系。 A rotationally symmetric coaxial lens that passes the luminous flux from the image display element;
A free-form surface lens having a rotationally asymmetric free-form surface through which a light beam from the coaxial lens passes,
A free-form surface mirror having a rotationally asymmetric free-form surface that reflects a light beam from the free-form surface lens;
Have
In the projection optical system that projects the light beam from the free-form curved mirror onto the projection surface,
The free-form surface lens is moved in a direction parallel to the optical axis of the coaxial lens, and is moved in a direction different from the parallel direction of the optical axis of the coaxial lens to perform a focusing operation according to the projection distance. Projection optical system. 映像表示素子からの光束を通す回転対称な同軸系レンズと、
前記同軸系レンズからの光束を通す回転非対称な自由曲面を有する自由曲面レンズと、
前記自由曲面レンズからの光束を反射する回転非対称な自由曲面を有する自由曲面ミラーと、
を有し、
前記自由曲面ミラーからの光束を被投射面に投射する投射光学系において、
前記自由曲面レンズを
前記同軸系レンズの光軸の平行方向と、
前記同軸系レンズの光軸の平行方向とは異なる方向と
で合成された方向へ移動することで投射距離に応じた合焦動作を行う
ことを特徴とする投射光学系。 A rotationally symmetric coaxial lens that passes the luminous flux from the image display element;
A free-form surface lens having a rotationally asymmetric free-form surface through which a light beam from the coaxial lens passes,
A free-form surface mirror having a rotationally asymmetric free-form surface that reflects a light beam from the free-form surface lens;
Have
In the projection optical system that projects the light beam from the free-form curved mirror onto the projection surface,
The free-form surface lens is parallel to the optical axis of the coaxial lens,
A projection optical system that performs a focusing operation according to a projection distance by moving in a direction synthesized with a direction different from a parallel direction of an optical axis of the coaxial lens. 請求項１、または２に記載の投射光学系において、
合焦動作の際に、前記同軸系レンズからの光束の通る範囲が前記自由曲面レンズの範囲よりも大きくなる場合には、
前記同軸系レンズからの周辺部の光束で前記自由曲面レンズを通らない範囲の大きさを等しくなる傾向となるように前記自由曲面レンズを移動することで投射距離に応じた合焦動作を行うことを特徴とする投射光学系。 In the projection optical system according to claim 1 or 2,
In the focusing operation, when the range through which the light beam from the coaxial lens passes is larger than the range of the free-form surface lens,
The focusing operation according to the projection distance is performed by moving the free-form surface lens so that the size of the range that does not pass through the free-form surface lens tends to be equal with the luminous flux in the peripheral part from the coaxial lens. Projection optical system. 請求項１、または２に記載の投射光学系において、
合焦動作の際に、前記同軸系レンズからの光束の通る範囲が前記自由曲面レンズの範囲よりも小さくなる場合には、
前記自由曲面レンズの周辺において、前記同軸系レンズからの光束の通らない範囲の大きさを等しくなる傾向となるように前記自由曲面レンズを移動することで投射距離に応じた合焦動作を行うことを特徴とする投射光学系。 In the projection optical system according to claim 1 or 2,
In the focusing operation, when the range through which the light beam from the coaxial lens passes is smaller than the range of the free-form surface lens,
A focusing operation according to the projection distance is performed by moving the free-form surface lens around the free-form surface lens so that the size of the range through which the light beam from the coaxial lens does not pass becomes equal. Projection optical system. 拡大側から順に、
回転非対称な自由曲面を有する自由曲面ミラーと、
回転非対称な自由曲面を有する自由曲面レンズと、
回転対称な同軸系レンズで構成され、全体として像面へ映像光を斜めに投射する投射光学系において、
自由曲面レンズを光束の進行方向に沿って移動させることで、投射距離に応じた合焦動作を行うことを特徴とする投射光学系。 From the enlarged side,
A free-form surface mirror having a rotationally asymmetric free-form surface;
A free-form surface lens having a rotationally asymmetric free-form surface;
In a projection optical system that is composed of rotationally symmetric coaxial lenses and projects image light obliquely to the image plane as a whole,
A projection optical system characterized by performing a focusing operation according to a projection distance by moving a free-form surface lens along a traveling direction of a light beam. 拡大側から順に、
回転非対称な自由曲面を有する自由曲面ミラーと、
回転非対称な自由曲面を有する自由曲面レンズ系と、
回転対称な同軸レンズ系で構成され、全体として像面へ映像光を斜めに投射する投射光学系において、
自由曲面レンズ系を該同軸レンズ系の光軸方向と異なる方向に移動させることで、投射距離に応じた合焦動作を行うことを特徴とする投射光学系。 From the enlarged side,
A free-form surface mirror having a rotationally asymmetric free-form surface;
A free-form surface lens system having a rotationally asymmetric free-form surface;
In a projection optical system that is composed of a rotationally symmetric coaxial lens system and projects image light obliquely to the image plane as a whole,
A projection optical system that performs a focusing operation according to a projection distance by moving a free-form surface lens system in a direction different from the optical axis direction of the coaxial lens system.
JP2008240199A 2008-09-19 2008-09-19 Projection optical system Pending JP2010072374A (en)

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Cited By (14)

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CN102269917B (en) * 2010-06-02 2014-03-19 日立民用电子株式会社 Projection type image display apparatus
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