JP2001242381A - Reflection image optical system for rear projection type monitor - Google Patents
Reflection image optical system for rear projection type monitorInfo
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- JP2001242381A JP2001242381A JP2000104095A JP2000104095A JP2001242381A JP 2001242381 A JP2001242381 A JP 2001242381A JP 2000104095 A JP2000104095 A JP 2000104095A JP 2000104095 A JP2000104095 A JP 2000104095A JP 2001242381 A JP2001242381 A JP 2001242381A
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- Prior art keywords
- screen
- reflecting
- optical system
- aspherical
- reflecting surface
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明による光学系は、反射型画
像素子プロジェクターないしは液晶プロジェクター内蔵
の、リアプロジェクション式モニターの投写結像光学系
として使用される。The optical system according to the present invention is used as a projection image forming optical system of a rear projection type monitor having a built-in reflection type image element projector or a liquid crystal projector.
【０００２】[0002]
【従来の技術】本発明に先行する技術として、レイシ
Ｇ．クックの文献（参考文献−１）と、特開平１０−１
１１４５８（参考文献−２）（図−１参照）と、インフ
ォコムジャパン２０００展示会における三洋電機株式会
社の配布資料（参考文献−３）の、３点を挙げる。参考
文献−１は、西暦１９９２年の論文で、それまでの反射
鏡系の設計の歴史、とりわけ３枚鏡のアナスチグマート
について纏めたものであり、技術的には本発明に連なる
底流を成すといえる。参考文献−２は、軸外しの非球面
鏡系による極めて広い包括角度をもつ反射結像光学系を
提供するもので、技術上の本質的な系譜としては次の参
考文献−３と相俟って、本発明に直接的に連なるもので
ある。図−１は参考文献−２の実施例から、光学系を見
る視点を本案の文脈に則り見やすい方向から描き直した
もので、１は第１反射鏡、２は第２反射鏡、３は第３反
射鏡である。図−２は参考文献−３からの図であり、図
−２の４は光学エンジン、５は第１反射鏡、６は第２反
射鏡、７は第３反射鏡、８は平面反射鏡、９はスクリー
ンである。こうして全体の厚みとして極めて薄型のリア
プロジェクション式モニターが可能となった。2. Description of the Related Art As a technology prior to the present invention, a laser
G. FIG. Cook's reference (Reference Document 1) and JP-A-10-1
There are three points: 11458 (Reference Document 2) (see FIG. 1) and a distributed document (Reference Document 3) of Sanyo Electric Co., Ltd. at Infocom Japan 2000 Exhibition. Reference 1 is a paper in 1992 in the Christian era, which summarizes the history of the design of the reflector system up to that point, particularly about the three-mirror anastigmat, and can be said to technically form an undercurrent linked to the present invention. . Reference-2 provides a reflection imaging optical system having an extremely wide coverage angle by an off-axis aspherical mirror system. The technical essential lineage is combined with the following Reference-3. Are directly linked to the present invention. FIG. 1 shows the viewpoint of viewing the optical system redrawn from the direction easy to see in the context of the present invention from the embodiment of Reference Document 2, where 1 is the first reflecting mirror, 2 is the second reflecting mirror, and 3 is the third reflecting mirror. It is a reflector. FIG. 2 is a diagram from Reference-3, where 4 is an optical engine, 5 is a first reflector, 6 is a second reflector, 7 is a third reflector, 8 is a plane reflector, 9 is a screen. In this way, an extremely thin rear projection type monitor as a whole was made possible.
【０００３】[0003]
【発明が解決しようとする課題】残された課題は２つあ
り、１つはスクリーンに入射する主光線の角度を、全体
の薄さを保ったまま、もう少しスクリーン垂線に近い角
度に緩めること、と２つ目はＦナンバーをもう少し明る
くすることである。図−２のスクリーン９の左側やや遠
方にはモニターを見る人の眼があり、スクリーンへ入射
した主光線はスクリーン透過後、人の眼の方向へ進むべ
きである。さらにはスクリーンを見る人の眼は、スクリ
ーン前方の様々の位置からスクリーンを見るから、スク
リーン透過後の光線はさまざまの方向に拡散するべきで
ある。そのため図−２には省略されているが、スクリー
ンの直前に近接してまずフレネルレンズを置き、主光線
の向きを最も理想的な眼の位置の方向へつまりはスクリ
ーン垂線の方向へ向け、つぎにスクリーンの構造を工夫
してこれをなるべく拡散させる；このような構造がとら
れる。問題はこの前者、即ちフレネルレンズで主光線を
スクリーン垂線の方向へ曲げるところに在る。一方では
装置全体の厚みは薄ければ薄いほど良い；そのため、図
−２に見るようにスクリーンに到達する光線はスクリー
ン垂線に対して大きな角度を持つようになり、フレネル
レンズ透過後の主光線をスクリーン垂線の方向に向ける
には、フレネルレンズに過大の負担がかかるようにな
る。２つ目の課題は、Ｆナンバーをもう少し明るくした
い、という点である。参考文献−２のＦナンバーは、７
前後であるので、場合によってはもう少し明るくしたい
場合がある。There are two problems left. One is to loosen the angle of the chief ray incident on the screen to an angle slightly closer to the screen normal while maintaining the overall thickness. The second is to make the F-number a bit brighter. The left side of the screen 9 in FIG. 2 has a human eye looking at the monitor a little farther away, and the principal ray incident on the screen should travel in the direction of the human eye after passing through the screen. Furthermore, since the eyes of the viewer of the screen see the screen from various positions in front of the screen, the light rays transmitted through the screen should spread in various directions. Therefore, although omitted in FIG. 2, a Fresnel lens is first placed close to the screen, and the principal ray is directed in the direction of the most ideal eye position, that is, in the direction of the screen normal. In addition, the structure of the screen is devised to diffuse as much as possible; such a structure is adopted. The problem lies in the former, that is, the bending of the chief ray by the Fresnel lens in the direction perpendicular to the screen. On the one hand, the thinner the overall device, the better; the light reaching the screen will have a large angle to the screen normal, as shown in Figure 2, and the chief ray after passing through the Fresnel lens will be Orientation in the direction perpendicular to the screen places an excessive burden on the Fresnel lens. The second problem is that we want to make the F-number a little brighter. The F-number in Reference-2 is 7
Because it is before and after, you may want to make it a little brighter in some cases.
【０００４】[0004]
【課題を解決するための手段】上記課題を解決するため
の手段として、スクリーン直前の平面反射鏡を球面の凹
面反射鏡とすることを提案する。すなわち図−２の光学
系の例で言えば平面鏡８を凹面の球面鏡とすることによ
り、スクリーンに到達する主光線のスクリーン垂線に対
する角度を緩め、またＦナンバーを少し明るい方向へ改
善する。As means for solving the above-mentioned problems, it is proposed that the plane reflecting mirror immediately before the screen is a spherical concave reflecting mirror. That is, in the example of the optical system shown in FIG. 2, by making the plane mirror 8 a concave spherical mirror, the angle of the principal ray reaching the screen with respect to the screen normal is relaxed, and the F-number is improved in a slightly brighter direction.
【０００５】この考え方を、屈折レンズ系の例を引いて
説明する。図−３は、特開昭５９−１９５２１１（参考
文献−４）の実施例の光学系断面図であるが、その４枚
目の大きなレンズは像高の中間部から周辺部での主光線
の角度を像面に対して垂直にするためのもので、コンデ
ンサーレンズの働きを成す。このレンズの働きによって
このレンズ系から射出される主光線はあらゆる像高でほ
ぼ像面に垂直となり、結果として像面側テレセントリッ
クなレンズとなる。[0005] This concept will be described with reference to an example of a refractive lens system. FIG. 3 is a sectional view of an optical system according to an embodiment of JP-A-59-195211 (Reference Document 4). The fourth large lens has a chief ray from the middle part to the peripheral part of the image height. This is to make the angle perpendicular to the image plane and acts as a condenser lens. By the function of this lens, the principal ray emitted from this lens system becomes almost perpendicular to the image plane at all image heights, and as a result, the lens is telecentric on the image plane side.
【０００６】[0006]
【作用】本発明におけるスクリーン直前の凹面鏡（球面
鏡）は、光学系のパワーとしてはプラスのパワーを持
ち、屈折レンズ系で言えば凸レンズに相当する。 即
ち、図−３のレンズ系で言えば、像面直前の大きな凸レ
ンズに相当する。つまりどちらも像面の近くに置かれた
プラスのパワーであり、主光線の方向を像面に垂直にす
る、ないしは垂直に近づける働きをする、という意味で
おなじ意味合いの機能を果たしている。異なる点は、参
照文献−４のねらいは像面に近い大きなレンズの働きで
あらゆる像高において主光線が像面にほぼ垂直にされる
のに対して、本発明の例では、この凹面鏡の働きにより
主光線のスクリーンに対する角度が垂直にされることは
なく、垂線に対する角度が緩められる、という範囲にと
どまっている点にある。本発明の例では、垂線に対する
角度の緩和効果は２０度から３５度くらいである。それ
でも、この凹面鏡の緩和効果が無い状態に比較すると大
きな改善であり、フレネルレンズに対する負担の軽減に
は大きな効果である。また、スクリーン直前の凹面球面
鏡は前述のごとくプラスのパワーを持ち反射結像光学系
全体のパワーを一部分担する結果となり、結像性能の低
下を招くことなく、Ｆナンバーを５程度まで明るくする
ことが出来る。 後述の実施例においては両者とも、結
像性能は画像素子上で画素ピッチ（ＸＧＡ）の２倍の空
間周波数において全画面６０％以上のＭＴＦを維持して
いる。The concave mirror (spherical mirror) immediately before the screen in the present invention has a positive power as the power of the optical system, and corresponds to a convex lens in the case of a refractive lens system. That is, in the lens system of FIG. 3, it corresponds to a large convex lens immediately before the image plane. In other words, both are positive powers placed near the image plane, and have the same meaning in that they function to make the direction of the principal ray perpendicular to or close to the image plane. The difference is that the aim of Reference Document 4 is that the chief ray is made almost perpendicular to the image plane at all image heights by the function of a large lens close to the image plane, whereas in the example of the present invention, the function of this concave mirror is used. Therefore, the angle of the principal ray with respect to the screen is not made vertical, but the angle with respect to the perpendicular is reduced. In the example of the present invention, the effect of reducing the angle with respect to the perpendicular is about 20 to 35 degrees. Nevertheless, this is a great improvement compared to a state where the concave mirror has no relaxing effect, and is a great effect for reducing the burden on the Fresnel lens. In addition, the concave spherical mirror immediately before the screen has a positive power as described above, and results in part of the power of the reflective imaging optical system. As a result, the F number can be increased to about 5 without lowering the imaging performance. Can be done. In the embodiments described later, in both cases, the imaging performance maintains the MTF of 60% or more on the entire screen at a spatial frequency twice the pixel pitch (XGA) on the image element.
【０００７】[0007]
【実施例−１】実施例−１の Ｒ、Ｄ、ｎ データを次
に示す。 ただし、上記に於いて４面と５面は左右対称型自由曲面
であり、その方程式を下記する： Ｚ＝ＣＲ＊＊２／（１＋√（１−（１＋ｋ）Ｃ＊＊２Ｒ＊＊２））＋Σ ＡｉＥｉ（ｘ，ｙ）……（１） 上式の第１項は通常の非球面式の第１項であり、第２項
以降のＡｉはｉ番目の項の係数であり、Ｅｉ（ｘ，ｙ）
はｘとｙの単純なベキ級数である。また上記レンズデー
タの第６面は軸外しの回転対称型非球面であり、その方
程式は下記の通り： Ｚ＝ＣＲ＊＊２／（１＋√（１−（１＋ｋ）Ｃ＊＊２Ｒ＊＊２））＋Σ ＡｉＲ＊＊（２ｉ）……（２） 上式中の ＊＊ はその後の整数回数分のベキ乗を表
す。スクリーンの大きさは６０インチ、光学系の最大厚
みは３０ｃｍである。[Embodiment 1] The R, D, and n data of Example 1 are shown below. However, in the above, surfaces 4 and 5 are left-right symmetric free-form surfaces, and the equation is as follows: Z = CR ** 2 / (1 + √ (1- (1 + k) C ** 2R ** 2) ) + Σ AiEi (x, y) (1) The first term of the above equation is the first term of the ordinary aspherical equation, and Ai after the second term is the coefficient of the i-th term, and Ei ( x, y)
Is a simple power series of x and y. The sixth surface of the lens data is an off-axis rotationally symmetric aspheric surface, and its equation is as follows: Z = CR ** 2 / (1 + √ (1- (1 + k) C ** 2R ** 2) )) + Σ AiR ** (2i) (2) ** in the above equation represents a power of an integer number thereafter. The size of the screen is 60 inches, and the maximum thickness of the optical system is 30 cm.
【０００８】[0008]
【実施例−２】実施例−２の Ｒ、Ｄ、ｎ データを次
に示す。 ただし各非球面の方程式は実施例−１に同じ。スクリー
ンの大きさは５０インチ、光学系の最大厚みは２５ｃ
ｍ、Ｆナンバーは５である。[Embodiment 2] The R, D, and n data of Embodiment 2 are shown below. However, the equations for each aspherical surface are the same as in Example-1. Screen size is 50 inches, maximum thickness of optical system is 25c
The m and F numbers are 5.
【０００９】[0009]
【発明の効果】極めて薄型の大画面モニターにおいて、
スクリーンに入射する主光線のスクリーン垂線に対する
角度が、２０度から３５度ほど緩和され、フレネルレン
ズに対する負担が軽減された。また同時にＦナンバーが
明るい方向に改善された。According to the present invention, in a very thin large screen monitor,
The angle of the chief ray incident on the screen with respect to the screen normal was relaxed by about 20 to 35 degrees, and the burden on the Fresnel lens was reduced. At the same time, the F-number improved in the brighter direction.
【図１】従来の技術を説明する参考文献−２の実施例の
光学系断面図FIG. 1 is a cross-sectional view of an optical system according to an embodiment of Reference Document 2, which describes a conventional technique.
【図２】従来の技術を説明する参考文献−３の光学系断
面図。FIG. 2 is a cross-sectional view of an optical system of Reference Document 3 explaining a conventional technique.
【図３】本案の技術的な系譜を説明するための参考文献
−４の光学系断面図。FIG. 3 is an optical system cross-sectional view of Reference Document 4 for describing a technical genealogy of the present invention.
【図４】本案の実施例−１の光学系側面図。FIG. 4 is a side view of the optical system according to the first embodiment of the present invention.
【図５】本案の実施例−２の光学系側面図。FIG. 5 is a side view of an optical system according to a second embodiment of the present invention.
１ 参考文献−２、実施例の第１反射鏡 ２ 参考文献−２、実施例の第２反射鏡 ３ 参考文献−２、実施例の第３反射鏡 ４ 参考文献−３、光学エンジン ５ 参考文献−３、第１反射鏡 ６ 参考文献−３、第２反射鏡 ７ 参考文献−３、第３反射鏡 ８ 参考文献−３、第４反射鏡（平面鏡） ９ 参考文献−３、スクリーン １０ 本案実施例−１、第１反射鏡 １１ 本案実施例−１、第２反射鏡 １２ 本案実施例−１、第３反射鏡 １３ 本案実施例−１、第４反射鏡（球面鏡） １４ 本案実施例−１、スクリーン １５ 本案実施例−２、第１反射鏡 １６ 本案実施例−２、第２反射鏡 １７ 本案実施例−２、第３反射鏡 １８ 本案実施例−２、第４反射鏡 １９ 本案実施例−２、第５反射鏡（球面鏡） ２０ 本案実施例−２、スクリーン 1 Reference-2, First Reflector in Example 2 Reference-2, Second Reflector in Example 3 Reference-2, Third Reflector in Example 4 Reference-3, Optical Engine 5 Reference -3, first reflector 6 reference-3, second reflector 7 reference-3, third reflector 8 reference-3, fourth reflector (plane mirror) 9 reference-3, screen 10 Example-1, 1st reflector 11 This invention example 1, 2nd reflection mirror 12 This invention example 1, 3rd reflection mirror 13 This invention example 1, 4th reflection mirror (spherical mirror) 14 This invention example-1 , Screen 15 Project embodiment-2, first reflector 16 Project embodiment-2, second reflector 17 Project embodiment-2, third reflector 18 Project embodiment-2, fourth reflector 19 Embodiment 19 -2, fifth reflecting mirror (spherical mirror) 20 Embodiment 2 of the present invention, screen
【参考文献】１ Ｃｒｉｔｉｃａｌ Ｒｅｖｉｅｗ Ｖ
ｏｌ．ＣＲ４１，Ｌｅｎｓ Ｄｅｓｉｇｎ，ｅｄ．Ｗａ
ｒｒｅｎ Ｊ．Ｓｍｉｔｈ（Ｊａｎ１９９２）Ｃｏｐｙ
ｒｉｇｈｔ ＳＰＩＥ ２ 特開平１０−１１１４５８ ３ インフォコムジャパン２０００展示会配布資料 三
洋電機株式会社 ４ 特開昭５９−１９５２１１[References] 1 Critical Review V
ol. CR41, Lens Design, ed. Wa
rren J. et al. Smith (Jan 1992) Copy
right SPIE 2 JP-A-10-111458 3 Infocom Japan 2000 exhibition distribution material Sanyo Electric Co., Ltd. 4 JP-A-59-195211
Claims (5)
て、スクリーン直前の反射鏡として球面反射鏡を設置
し、これを加えて合計４枚ないし５枚の反射鏡から成
る、リアプロジェクション式モニター用反射結像光学
系。1. In addition to three or four aspherical reflecting mirror systems, a spherical reflecting mirror is installed as a reflecting mirror immediately before a screen, and in addition to this, a total of four or five reflecting mirrors are provided. Reflective imaging optics for projection monitors.
けて順に、まず必要な場合は画像素子パネルに近接して
クロスダイクロイックプリズムを置き、そこからある程
度の距離をあけて非球面の第１反射面を置き、やや距離
をあけて非球面の第２反射面を置き、やや距離をあけて
非球面の第３反射面を置き、さらにやや距離をあけて球
面の凹面を反射面とした第４反射面を置き、第５面のス
クリーン面に到達するように構成した反射結像光学系。2. A cross dichroic prism is first placed, if necessary, close to the image element panel from the image element panel side to the screen side, and at a certain distance therefrom, an aspheric first reflecting surface. , The aspherical second reflective surface is placed at a slight distance, the aspherical third reflective surface is placed at a slight distance, and the spherical concave surface is taken at a further distance. A reflection imaging optical system which is arranged so as to reach a fifth screen surface.
型自由曲面とし、第２反射面を左右対称型自由曲面と
し、第３反射面を軸外しの回転対称型非球面とし、その
他は請求項２の構成とした反射結像光学系。3. The method according to claim 2, wherein the first reflecting surface is a symmetric free-form surface, the second reflecting surface is a symmetric free-form surface, and the third reflecting surface is an off-axis rotationally symmetric aspheric surface. 3. A reflection imaging optical system having the other components according to claim 2.
けて順に、まず必要な場合は画像素子パネルに近接して
クロスダイクロイックプリズムを置き、そこからある程
度の距離をあけて非球面の第１反射面を置き、やや距離
をあけて非球面の第２反射面を置き、やや距離をあけて
非球面の第３反射面を置き、やや距離を開けて非球面の
第４反射面を置き、さらにやや距離をあけて球面の凹面
を反射面とした第５反射面を置き、第６面のスクリーン
面に到達するように構成した反射結像光学系。4. A cross dichroic prism is placed, if necessary, close to the image element panel in order from the image element panel side to the screen side, and at a certain distance therefrom, an aspheric first reflecting surface. , The aspherical second reflecting surface is placed at a slight distance, the aspherical third reflecting surface is placed at a slight distance, the aspherical fourth reflecting surface is placed at a slight distance, and further slightly A reflection imaging optical system configured to place a fifth reflection surface having a concave surface of a spherical surface as a reflection surface at a distance and to reach a sixth screen surface.
回転対称型非球面とし、第２反射面を左右対称型自由曲
面とし、第３反射面を左右対称型自由曲面とし、第４反
射面を軸外しの回転対称型非球面とし、その他は請求項
４の構成とした反射結像光学系。5. The method according to claim 4, wherein the first reflecting surface is an off-axis rotationally symmetric aspherical surface, the second reflecting surface is a left-right symmetric free-form surface, and the third reflecting surface is a left-right symmetric free-form surface. 5. A reflective imaging optical system according to claim 4, wherein the fourth reflecting surface is an off-axis rotationally symmetric aspherical surface, and the other is configured as in claim 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000104095A JP2001242381A (en) | 2000-03-01 | 2000-03-01 | Reflection image optical system for rear projection type monitor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000104095A JP2001242381A (en) | 2000-03-01 | 2000-03-01 | Reflection image optical system for rear projection type monitor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2001242381A true JP2001242381A (en) | 2001-09-07 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000104095A Pending JP2001242381A (en) | 2000-03-01 | 2000-03-01 | Reflection image optical system for rear projection type monitor |
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| Country | Link |
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| JP (1) | JP2001242381A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004309765A (en) * | 2003-04-07 | 2004-11-04 | Canon Inc | Reflecting optical system and projector using reflecting optical system |
| US6822811B2 (en) | 2002-03-27 | 2004-11-23 | Minolta Co., Ltd. | Oblique projection optical system and method for setting the same |
| JP2006039032A (en) * | 2004-07-23 | 2006-02-09 | Sharp Corp | Projection display device |
| US7101052B2 (en) | 2001-09-04 | 2006-09-05 | Canon Kabushiki Kaisha | Projection optical system and optical system |
| CN100416338C (en) * | 2005-09-13 | 2008-09-03 | 中华映管股份有限公司 | Back projector display device |
| JP2009211099A (en) * | 2009-06-22 | 2009-09-17 | Canon Inc | Reflecting optical system and projecting device using the same |
| JP2010014816A (en) * | 2008-07-01 | 2010-01-21 | Mitsubishi Electric Corp | Rear-projection-type display apparatus |
| CN1770005B (en) * | 2004-11-01 | 2010-05-26 | 株式会社日立制作所 | Image display apparatus, as well as, fresnel lens sheet and screen to be used therein |
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2000
- 2000-03-01 JP JP2000104095A patent/JP2001242381A/en active Pending
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7101052B2 (en) | 2001-09-04 | 2006-09-05 | Canon Kabushiki Kaisha | Projection optical system and optical system |
| US7182466B2 (en) | 2001-09-04 | 2007-02-27 | Canon Kabushiki Kaisha | Projection optical system and optical system |
| US6822811B2 (en) | 2002-03-27 | 2004-11-23 | Minolta Co., Ltd. | Oblique projection optical system and method for setting the same |
| JP2004309765A (en) * | 2003-04-07 | 2004-11-04 | Canon Inc | Reflecting optical system and projector using reflecting optical system |
| US7130114B2 (en) | 2003-04-07 | 2006-10-31 | Canon Kabushiki Kaisha | Catoptric optical system |
| JP4510399B2 (en) * | 2003-04-07 | 2010-07-21 | キヤノン株式会社 | Reflective optical system and projection apparatus using the same |
| JP2006039032A (en) * | 2004-07-23 | 2006-02-09 | Sharp Corp | Projection display device |
| CN1770005B (en) * | 2004-11-01 | 2010-05-26 | 株式会社日立制作所 | Image display apparatus, as well as, fresnel lens sheet and screen to be used therein |
| CN100416338C (en) * | 2005-09-13 | 2008-09-03 | 中华映管股份有限公司 | Back projector display device |
| JP2010014816A (en) * | 2008-07-01 | 2010-01-21 | Mitsubishi Electric Corp | Rear-projection-type display apparatus |
| JP2009211099A (en) * | 2009-06-22 | 2009-09-17 | Canon Inc | Reflecting optical system and projecting device using the same |
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