JP4846933B2 - Binocular image display device - Google Patents

Description

ただし、Ｚを光の進行方向を正とした光軸（軸上主光線）とし、ｙを光軸と垂直な方向にとる。ここで、Ｒは近軸曲率半径、Ｋは円錐定数、Ａ、Ｂ、Ｃ、Ｄ、…はそれぞれ４次、６次、８次、１０次の非球面係数である。この定義式のＺ軸が回転対称非球面の軸となる。
【００８９】
なお、データの記載されていない自由曲面、非球面に関する項は０である。屈折率については、ｄ線（波長５８７．５６ｎｍ）に対するものを表記してある。
長さの単位はｍｍである。
【００９０】
以下に示す数値実施例１〜３は、上記の一方の射出瞳１Ｌから画像表示素子３、３Ｌに向う逆光線追跡で表されている。
【００９１】
実施例１は、片側瞳径横４０ｍｍ、上下１５ｍｍであり、観察画像は瞳位置から４００ｍｍ前方で、水平５５ｍｍ、垂直４１．２５ｍｍの接眼光学系３２上に結像され、左右の光軸は内向角を持って接眼光学系３２から射出し、その内向角は瞳位置より接眼光学系３２側に３２０ｍｍの位置で交差する。画像表示素子３としては８．９４ｍｍ×６．７１ｍｍの表示素子を使用している。
【００９２】
図８に実施例１のＹ−Ｚ平面に投影した片方の光学系の光路図、図９にそのＸ−Ｚ平面に投影した光路図、図１０にＸ−Ｚ平面に投影した両側の光学系の主光線のみの光路図、図１１に図１０の画像表示素子３、リレー光学系３１の偏心プリズム１０近傍の拡大図をそれぞれ示す。
【００９３】
後記の数値データは、左側の射出瞳１Ｌから画像表示素子３に至るものであり、右側の射出瞳１Ｒから画像表示素子３に至る光学系のデータは、Ｙ−Ｚ面を対称面として面対称の位置に配置したものとなる。
【００９４】
この実施例において、リレー光学系３１を構成する偏心プリズム１０の第４面１４（数値データ中の５面）は、Ｙ−Ｚ面を対称面として面対称な不連続面からなり、左側の射出瞳１Ｌの形成に関与する一方の面１４Ｌのみの面形状を示してある。この面１４ＬはＹ−Ｚ面よりＸ軸負側に設けられ、Ｙ−Ｚ面よりＸ軸正側にはそれと面対称な他方の面１４Ｒが設けられる（図１１）。第４面１４を対称面に対称な２つの光学面１４Ｌ、１４Ｒよりなる不連続面として形成することにより、本実施例の光学系の対称面（Ｙ−Ｚ面）を中心に相互に７５ｍｍは離れた横４０ｍｍ、上下１５ｍｍの瞳径の左右の射出瞳１Ｌ、１Ｒを持った光学系が構成できる。
【００９５】
実施例１の光学系は、図８〜図１１に示すように、図２の形態に対応する両眼画像表示装置用の光学系で、射出瞳１Ｌ（１Ｒ）に面した接眼光学系３２は射出瞳１Ｌ（１Ｒ）側の面がフレネル透過面、反対側の面が平面のフレネルレンズからなり、その入射側に光路折り返し用の反射面（平面鏡）３３が配置され、その反射面３３に面してリレー光学系３１が配置されている。このリレー光学系３１は画像表示素子３に面した偏心プリズム１０からなり、この実施例の偏心プリズム１０は、画像表示素子３に面する第１面１１と、反射面３３に面する第４面１４と、第１面１１と第４面１４の間に配置された２つの反射面の第２面１２、第３面１３とからなり、上記のように、第４面１４は光学系の対称面（Ｙ−Ｚ面）に対して面対称な不連続面を構成する２つの面１４Ｌ、１４Ｒからなる。
【００９６】
この実施例において、画像表示素子３からの表示光は偏心プリズム１０の第１面１１で屈折してプリズム内に入射し、第２面１２と第３面１３で内部反射を繰り返し、第４面１４の２つの面１４Ｌ、１４Ｒで別々の光路に沿った光束として屈折してプリズム外に射出し、その２つの光束は反射面３３で折り返され、接眼光学系３２のフレネルレンズ面上に画像表示素子３の左右の眼用の拡大像を二重像として結像し、接眼光学系３２で屈折された光束はそれぞれ左右の射出瞳１Ｌ、１Ｒに収束する。その際、射出瞳１Ｌ、１Ｒの位置より接眼光学系３２側に３２０ｍｍの点Ｐで左右の光軸２Ｌ、２Ｒは交差しているため、接眼光学系３２のフレネルレンズ面上に結像された左右の眼用の拡大像はこの点Ｐ近傍で融像され、あたかも空中に浮いているように表示されているように表示像が見える。
【００９７】
なお、この実施例において、接眼光学系３２の平面（数値データ中の３面）近傍に上下方向に拡散性を持ったレンチキュラーシートを配置し、上下方向にのみ瞳を拡大することによりさらに広い観察範囲を確保することができる。
【００９８】
この実施例においては、偏心プリズム１０の第１面１１〜第４面１４全てに自由曲面を用いており、接眼光学系３２のフレネルレンズのフレネル透過面には非球面を用いている。
【００９９】
実施例２は、片側瞳径横１５ｍｍ、上下１０ｍｍであり、観察画像は瞳位置から４００ｍｍ前方で、水平５５ｍｍ、垂直４１．２５ｍｍの接眼光学系３２上に結像され、左右の光軸は内向角を持って接眼光学系３２から射出し、その内向角は瞳位置より接眼光学系３２側に３２０ｍｍの位置で交差する。左右の画像表示素子３Ｌ、３Ｒとしては８．９４ｍｍ×６．７１ｍｍの表示素子を使用している。
【０１００】
図１２に実施例２のＹ−Ｚ平面に投影した片方の光学系の主光線のみの光路図、図１３にそのＸ−Ｚ平面に投影した同様の光路図、図１４にＸ−Ｚ平面に投影した両側の光学系の同様の光路図をそれぞれ示す。
【０１０１】
後記の数値データは、左側の射出瞳１Ｌから画像表示素子３Ｌに至るものであり、右側の射出瞳１Ｒから画像表示素子３Ｒに至る光学系のデータは、Ｙ−Ｚ面を対称面として面対称の位置に配置したものとなる。
【０１０２】
実施例２の光学系は、図１２〜図１４に示すように、図３の形態に対応する両眼画像表示装置用の光学系で、リレー光学系３１は、Ｙ−Ｚ面を対称面として面対称の一対の偏心プリズム１０Ｌ、１０Ｒを用い、それぞれの入射面１１に面して左右別々の画像表示素子３Ｌ、３Ｒを配置した例である。
【０１０３】
この実施例の光学系は、図１２〜図１４に示すように、射出瞳１Ｌ、１Ｒに面した接眼光学系３２は射出瞳１Ｌ、１Ｒ側の面がフレネル透過面、反対側の面が平面のフレネルレンズからなり、その入射側に光路折り返し用の反射面（平面鏡）３３が配置され、その反射面３３に面して一対の偏心プリズム１０Ｌ、１０Ｒからなるリレー光学系３１が配置されている。この実施例の偏心プリズム１０Ｌ、１０Ｒは、それぞれ画像表示素子３Ｌ、３Ｒに面する第１面１１と、反射面３３に面する第４面１４と、第１面１１と第４面１４の間に配置された２つの反射面の第２面１２、第３面１３とからなり、上記のように、偏心プリズム１０Ｌ、１０Ｒは光学系の対称面（Ｙ−Ｚ面）に対して面対称な形状になっている。
【０１０４】
この実施例においては、左右の画像表示素子３Ｌ、３Ｒに左右の眼用の画像を表示し、左右の偏心プリズム１０Ｌ、１０Ｒで共通の接眼光学系３２近傍に左右の画像表示素子３Ｌ、３Ｒの像を投影し、射出瞳１Ｌ、１Ｒに位置する左右両眼に左右の眼用の画像を表示するものである。
【０１０５】
すなわち、左右の画像表示素子３Ｌ、３Ｒからの表示光は左右の偏心プリズム１０Ｌ、１０Ｒの第１面１１で屈折してプリズム内に入射し、第２面１２と第３面１３で内部反射を繰り返し、第４面１４で屈折してプリズム外に射出し、その２つの光束は反射面３３で折り返され、接眼光学系３２のフレネルレンズ面上に左右の画像表示素子３Ｌ、３Ｒの左右の眼用の拡大像を二重像として結像し、接眼光学系３２で屈折された光束はそれぞれ左右の射出瞳１Ｌ、１Ｒに収束する。その際、射出瞳１Ｌ、１Ｒの位置より接眼光学系３２側に３２０ｍｍの点Ｐで左右の光軸２Ｌ、２Ｒは交差しているため、接眼光学系３２のフレネルレンズ面上に結像された左右の眼用の拡大像はこの点Ｐ近傍で融像され、あたかも空中に浮いているように表示されているように表示像が見える。
【０１０６】
なお、この実施例においても、接眼光学系３２の平面（数値データ中の３面）近傍に上下方向に拡散性を持ったレンチキュラーシートを配置し、上下方向にのみ瞳を拡大することによりさらに広い観察範囲を確保することができる。
【０１０７】
この実施例においては、偏心プリズム１０Ｌ、１０Ｒの第１面１１〜第４面１４全てに自由曲面を用いており、接眼光学系３２のフレネルレンズのフレネル透過面には非球面を用いている。
【０１０８】
実施例３は、片側瞳径１０ｍｍであり、観察画像は瞳位置から４００ｍｍ前方で、水平５５ｍｍ、垂直４１．２５ｍｍの接眼光学系３２上に結像され、左右の光軸は内向角を持って接眼光学系３２から射出し、その内向角は瞳位置より接眼光学系３２側に３２０ｍｍの位置で交差する。画像表示素子３としては８．９４ｍｍ×６．７１ｍｍの表示素子を使用している。
【０１０９】
図１５に実施例３のＹ−Ｚ平面に投影した片方の光学系の主光線のみの光路図、図１６にそのＸ−Ｚ平面に投影した同様の光路図、図１７にＸ−Ｚ平面に投影した両側の光学系の同様の光路図、図１８に図１７の画像表示素子３、リレー光学系３１の偏心プリズム１０近傍の拡大図をそれぞれ示す。
【０１１０】
後記の数値データは、左側の射出瞳１Ｌから画像表示素子３に至るものであり、右側の射出瞳１Ｒから画像表示素子３に至る光学系のデータは、Ｙ−Ｚ面を対称面として面対称の位置に配置したものとなる。
【０１１１】
この実施例は、実施例１に対して、接眼光学系３２は射出瞳１Ｌ（１Ｒ）側の面が自由曲面の透過面２１、反対側の面がフレネル反射面２２からなるフレネル反射鏡２０を用い、光路折り返し用の反射面３３を省いた例であり、リレー光学系３１を構成する偏心プリズム１０の第４面１４（数値データ中の５面）は、Ｙ−Ｚ面を対称面として面対称な不連続面からなり、左側の射出瞳１Ｌの形成に関与する一方の面１４Ｌのみの面形状を示してある。この面１４ＬはＹ−Ｚ面よりＸ軸負側に設けられ、Ｙ−Ｚ面よりＸ軸正側にはそれと面対称な他方の面１４Ｒが設けられる（図１８）。第４面１４を対称面に対称な２つの光学面１４Ｌ、１４Ｒよりなる不連続面として形成することにより、本実施例の光学系の対称面（Ｙ−Ｚ面）を中心に相互に７５ｍｍは離れた瞳径１０ｍｍの左右の射出瞳１Ｌ、１Ｒを持った光学系が構成できる。
【０１１２】
実施例３の光学系は、図１５〜図１８に示すように、射出瞳１Ｌ（１Ｒ）に面した接眼光学系３２は射出瞳１Ｌ（１Ｒ）側の面が自由曲面の透過面２１、反対側の面がフレネル反射面２２からなるフレネル反射鏡２０からなり、その反射側にリレー光学系３１が配置されている。このリレー光学系３１は画像表示素子３に面した偏心プリズム１０からなり、この実施例の偏心プリズム１０は、画像表示素子３に面する第１面１１と、反射面３３に面する第４面１４と、第１面１１と第４面１４の間に配置された２つの反射面の第２面１２、第３面１３とからなり、上記のように、第４面１４は光学系の対称面（Ｙ−Ｚ面）に対して面対称な不連続面を構成する２つの面１４Ｌ、１４Ｒからなる。
【０１１３】
この実施例において、画像表示素子３からの表示光は偏心プリズム１０の第１面１１で屈折してプリズム内に入射し、第２面１２と第３面１３で内部反射を繰り返し、第４面１４の２つの面１４Ｌ、１４Ｒで別々の光路に沿った光束として屈折してプリズム外に射出し、その２つの光束は接眼光学系３２のフレネル反射鏡２０の透過面２１上に画像表示素子３の左右の眼用の拡大像を二重像として結像し、接眼光学系３２で反射された光束はそれぞれ左右の射出瞳１Ｌ、１Ｒに収束する。その際、射出瞳１Ｌ、１Ｒの位置より接眼光学系３２側に３２０ｍｍの点Ｐで左右の光軸２Ｌ、２Ｒは交差しているため、フレネル反射鏡２０の透過面２１上に結像された左右の眼用の拡大像はこの点Ｐ近傍で融像され、あたかも空中に浮いているように表示されているように表示像が見える。
【０１１４】
この実施例においては、偏心プリズム１０の第１面１１〜第４面１４全てに自由曲面を用いており、フレネル反射鏡２０の透過面２１に自由曲面を用いており、フレネル反射鏡２０のフレネル反射面２２には非球面を用いている。
【０１１５】
以下に各実施例の数値データを示すが、以下の表中の“ＦＦＳ”は自由曲面、“ＡＳＳ”は非球面、“ＲＥ”は反射面、“ＦＲ”はフレネル面、“ＥＩＭ”は結像面をそれぞれ示す。
【０１１６】

【０１１７】

【０１１８】

【０１１９】
上記実施例１の片側の光学系の横収差を図１９に示す。この横収差図において、括弧内に示された数字は（水平画角，垂直画角）を表し、その画角における横収差を示す。
【０１２０】
さて、以上の説明では、本発明の両眼画像表示装置は、１個あるいは２個の画像表示素子３、３Ｌ、３Ｒに表示された画像を両眼で空中に融像して拡大観察するものとして説明してきたが、その代わりに、他の光学系によって結像された空中像を両眼で空中に融像して拡大観察する両眼画像表示装置としても構成することもできる。図２０に、図２に示すような形態を用いて、双眼実体観察装置として構成する例を示す。立体物Ｏは左右の瞳３６Ｌ、３６Ｒを持つ対物レンズ３５を経て、同じ像面３’上に左右の空中像として結像される。その左右の空中像は、例えば実施例１に示したような偏心プリズム１０からなるリレー光学系３１と接眼光学系３２とから構成された本発明の光学系を経て、例えば接眼光学系３２上に重畳して結像され、それぞれの光束は左右の射出瞳１Ｌ、１Ｒに別々に入射するので、この射出瞳１Ｌ、１Ｒに両眼を位置させることにより、立体物Ｏの拡大立体像を観察することができるようになる。
【０１２１】
なお、本発明の両眼画像表示装置のリレー光学系に用いる偏心プリズム光学系としては、以上の実施例１〜３で用いたタイプ及び図２１に示した内部反射回数２〜３回のタイプのプリズムに限定されず、他のタイプの偏心プリズム単体あるいはそれらの偏心プリズムの組み合わせからなる光学系を用いることができる。
【０１２２】
以上の本発明の両眼画像表示装置は例えば次のように構成することができる。
【０１２３】
〔１〕 画像表示素子に表示された画像又は他の光学系によって結像された空中像を物点としてこれを投影するリレー光学系と、前記リレー光学系からの光束を観察者の眼に向って収束する収束作用を有する接眼光学系とを有する画像表示装置において、
前記リレー光学系は、前記画像表示素子に表示された画像又は前記空中像を物点としてその物点から発する光束を２つの光路に分割すると共に、その２つの光路上に左右の射出瞳を形成する光学系からなり、
前記接眼光学系は、前記リレー光学系で分割された２つの光路を観察者両眼に対応する左右の射出瞳に導くと共に、前記リレー光学系によって形成された左右の射出瞳を観察者両眼に対応する左右の射出瞳位置に投影する少なくとも正のパワーを有し、
前記接眼光学系から観察者両眼に対応する左右の射出瞳に導かれる２つの光路の光軸は、前記接眼光学系より前記観察者両眼側で交差するように配置されていることを特徴とする両眼画像表示装置。
【０１２４】
〔２〕 前記リレー光学系は、前記画像表示素子に表示された画像又は他の光学系によって結像された空中像の像を前記接眼光学系近傍に結像するように構成されていることを特徴とする上記１記載の両眼画像表示装置。
【０１２５】
〔３〕 前記接眼光学系近傍に指向性の拡散性を持つ光学面が配置されていることを特徴とする上記２記載の両眼画像表示装置。
【０１２６】
〔４〕 前記リレー光学系による左右の射出瞳各々の形が左右に長い楕円であり、前記指向性の拡散性を持つ光学面がその楕円の長軸に直交する上下方向のみに拡散作用を有する光学面であることを特徴とする上記３記載の両眼画像表示装置。
【０１２７】
〔５〕 前記リレー光学系は、屈折率（ｎ）が１よりも大きい（ｎ＞１）媒質で形成された偏心プリズムを有し、その偏心プリズムが、前記物点から発せられた光束をプリズム内に入射する入射面と、その光束をプリズム内で反射する少なくとも１つの反射面と、光束をプリズム外に射出する射出面とを有し、かつ、少なくとも１つの回転非対称面を有し、少なくとも１つの光学作用面は隣接する少なくとも２つの面からなる不連続面で構成され、他の光学作用面は分割された少なくとも２つの光路内に共通に配置されてなることを特徴とする上記１から４の何れか１項記載の両眼画像表示装置。
【０１２８】
〔６〕 前記偏心プリズムが、２つの反射面を備え、入射面と第１反射面と第２反射面と射出面からなり、入射面と第１反射面とを結ぶ光路が第２反射面と射出面とを結ぶ光路とプリズム内で交差するようになっていることを特徴とする上記５記載の両眼画像表示装置。
【０１２９】
〔７〕 前記偏心プリズムが、３つの反射面を備え、その内の第３反射面が前記画像表示素子又は前記空中像からの光を入射させる入射面を兼用した面にて形成され、第１反射面が射出面を兼用した面にて形成されていることを特徴とする上記５記載の両眼画像表示装置。
【０１３０】
〔８〕 前記偏心プリズムが、２つの反射面を備え、入射面と、射出面を兼用した第１反射面と、第２反射面とからなることを特徴とする上記５記載の両眼画像表示装置。
【０１３１】
〔９〕 前記偏心プリズムが、２つの反射面を備え、入射面を兼用した第２反射面と、第１反射面と、射出面とからなることを特徴とする上記５記載の両眼画像表示装置。
【０１３２】
〔１０〕 前記偏心プリズムは、対称面を１面のみ有する自由曲面からなり、前記不連続面以外のプリズムを構成する各面は略同一面内の対称面を有していることを特徴とする上記５から９の何れか１項記載の両眼画像表示装置。
【０１３３】
〔１１〕 前記接眼光学系は、少なくとも１つの回転非対称面を有することを特徴とする上記１から１０の何れか１項記載の両眼画像表示装置。
【０１３４】
〔１２〕 前記接眼光学系は、反射光学系からなることを特徴とする上記１から１１の何れか１項記載の両眼画像表示装置。
【０１３５】
〔１３〕 前記接眼光学系は、フレネル反射面を有することを特徴とする上記１２記載の両眼画像表示装置。
【０１３６】
〔１４〕 前記接眼光学系は、屈折光学系からなることを特徴とする上記１から１１の何れか１項記載の両眼画像表示装置。
【０１３７】
〔１５〕 前記接眼光学系は、フレネル透過面を有することを特徴とする上記１４記載の両眼画像表示装置。
【０１３８】
〔１６〕 前記接眼光学系は、回折光学系からなることを特徴とする上記１から１１の何れか１項記載の両眼画像表示装置。
【０１３９】
〔１７〕 画像表示素子に表示された画像又は他の光学系によって結像された空中像を物点としてこれを投影するリレー光学系と、前記リレー光学系からの光束を観察者の眼に向って収束する収束作用を有する接眼光学系とを有する画像表示装置において、
前記画像表示素子は一対の画像表示素子からなり、前記空中像は並列に結像された一対の空中像からなり、
前記リレー光学系は、前記画像表示素子に表示された一対の画像又は前記並列された一対の空中像各々を物点としてそれら物点から発する光束を別々の光路に導くと共に、その２つの光路上に左右の射出瞳を形成する光学系からなり、
前記接眼光学系は、前記リレー光学系を経た２つの光路を観察者両眼に対応する左右の射出瞳に導くと共に、前記リレー光学系によって形成された左右の射出瞳を観察者両眼に対応する左右の射出瞳位置に投影する少なくとも正のパワーを有し、
前記接眼光学系から観察者両眼に対応する左右の射出瞳に導かれる２つの光路の光軸は、前記接眼光学系より前記観察者両眼側で交差するように配置されていることを特徴とする両眼画像表示装置。
【０１４０】
〔１８〕 前記リレー光学系は、前記一対の画像表示素子に表示された画像又は前記並列に結像された一対の空中像の像を前記接眼光学系近傍に結像するように構成されていることを特徴とする上記１７記載の両眼画像表示装置。
【０１４１】
〔１９〕 前記接眼光学系近傍に指向性の拡散性を持つ光学面が配置されていることを特徴とする上記１８記載の両眼画像表示装置。
【０１４２】
〔２０〕 前記リレー光学系による左右の射出瞳各々の形が左右に長い楕円であり、前記指向性の拡散性を持つ光学面がその楕円の長軸に直交する上下方向のみに拡散作用を有する光学面であることを特徴とする上記１９記載の両眼画像表示装置。
【０１４３】
〔２１〕 前記リレー光学系は、屈折率（ｎ）が１よりも大きい（ｎ＞１）媒質で形成された一対の偏心プリズムを有し、各偏心プリズムは、対応する画像表示素子又は空中像から射出された光束をプリズム内に入射する入射面と、その光束をプリズム内で反射する少なくとも１つの反射面と、光束をプリズム外に射出する射出面とを有し、その少なくとも１つの反射面が光束にパワーを与える回転非対称面からなることを特徴とする上記１７から２０の何れか１項記載の両眼画像表示装置。
【０１４４】
〔２２〕 前記偏心プリズムが、２つの反射面を備え、入射面と第１反射面と第２反射面と射出面からなり、入射面と第１反射面とを結ぶ光路が第２反射面と射出面とを結ぶ光路とプリズム内で交差するようになっていることを特徴とする上記２１記載の両眼画像表示装置。
【０１４５】
〔２３〕 前記偏心プリズムが、３つの反射面を備え、その内の第３反射面が対応する画像表示素子又は空中像からの光を入射させる入射面を兼用した面にて形成され、第１反射面が射出面を兼用した面にて形成されていることを特徴とする上記２１記載の両眼画像表示装置。
【０１４６】
〔２４〕 前記偏心プリズムが、２つの反射面を備え、入射面と、射出面を兼用した第１反射面と、第２反射面とからなることを特徴とする上記２１記載の両眼画像表示装置。
【０１４７】
〔２５〕 前記偏心プリズムが、２つの反射面を備え、入射面を兼用した第２反射面と、第１反射面と、射出面とからなることを特徴とする上記２１記載の両眼画像表示装置。
【０１４８】
〔２６〕 前記偏心プリズムは、対称面を１面のみ有する自由曲面からなり、前記不連続面以外のプリズムを構成する各面は略同一面内の対称面を有していることを特徴とする上記２１から２５の何れか１項記載の両眼画像表示装置。
【０１４９】
〔２７〕 前記接眼光学系は、少なくとも１つの回転非対称面を有することを特徴とする上記２１から２６の何れか１項記載の両眼画像表示装置。
【０１５０】
〔２８〕 前記接眼光学系は、反射光学系からなることを特徴とする上記２１から２７の何れか１項記載の両眼画像表示装置。
【０１５１】
〔２９〕 前記接眼光学系は、フレネル反射面を有することを特徴とする上記２８記載の両眼画像表示装置。
【０１５２】
〔３０〕 前記接眼光学系は、屈折光学系からなることを特徴とする上記２１から２７の何れか１項記載の両眼画像表示装置。
【０１５３】
〔３１〕 前記接眼光学系は、フレネル透過面を有することを特徴とする上記３０記載の両眼画像表示装置。
【０１５４】
〔３２〕 前記接眼光学系は、回折光学系からなることを特徴とする上記２１から２７の何れか１項記載の両眼画像表示装置。
【０１５５】
【発明の効果】
以上の説明から明らかなように、本発明により、両眼で立体映像等として観察可能で、小型で部品点数の少なく携帯可能な両眼画像表示装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の両眼画像表示装置の基本形態を示す模式的斜視図である。
【図２】リレー光学系を単一の偏心プリズムから構成する場合の両眼画像表示装置の構成を示す模式的斜視図である。
【図３】リレー光学系を一対の偏心プリズムから構成する場合の両眼画像表示装置の構成を示す模式的斜視図である。
【図４】リレー光学系を構成する単一の偏心プリズムの構成を示す模式的斜視図である。
【図５】左右に長い楕円にして形成される射出瞳を示す図である。
【図６】接眼光学系に配置される拡散性の光学面の拡散性を説明するための図である。
【図７】手持ちビュワータイプの形態に構成された本発明の両眼画像表示装置を示す模式的斜視図である。
【図８】本発明の実施例１のＹ−Ｚ平面に投影した片方の光学系の光路図である。
【図９】実施例１のＸ−Ｚ平面に投影した片方の光学系の光路図である。
【図１０】実施例１の両側の光学系のＸ−Ｚ平面に投影した主光線のみの光路図である。
【図１１】図１０の画像表示素子、リレー光学系の偏心プリズム近傍の拡大図である。
【図１２】実施例２のＹ−Ｚ平面に投影した片方の光学系の主光線のみの光路図である。
【図１３】実施例２のＸ−Ｚ平面に投影した片方の光学系の主光線のみの光路図である。
【図１４】実施例２の両側の光学系のＸ−Ｚ平面に投影した主光線のみの光路図である。
【図１５】実施例３のＹ−Ｚ平面に投影した片方の光学系の主光線のみの光路図である。
【図１６】実施例３のＸ−Ｚ平面に投影した片方の光学系の主光線のみの光路図である。
【図１７】実施例３の両側の光学系のＸ−Ｚ平面に投影した主光線のみの光路図である。
【図１８】図１７の画像表示素子、リレー光学系の偏心プリズム近傍の拡大図である。
【図１９】実施例１の片側の光学系の横収差を示す図である。
【図２０】本発明に基づき双眼実体観察装置として構成する例を示す光路図である。
【図２１】本発明の両眼画像表示装置のリレー光学系に使用可能な偏心プリズムのいくつかの例を示す図である。
【符号の説明】
１Ｌ、１Ｒ…射出瞳
２Ｌ、２Ｒ…光軸
３、３Ｌ、３Ｒ…画像表示素子
３’…像面
１０、１０Ｌ、１０Ｒ…偏心プリズム
１１…第１面
１２…第２面
１３…第３面
１４…第４面
１４Ｌ、１４Ｒ…不連続面を構成する光学面
２０…フレネル反射鏡
２１…接眼光学系の射出瞳側の透過面
２２…接眼光学系の反対側のフレネル反射面
３０…表示装置本体
３１…リレー光学系
３２…接眼光学系
３３…反射面（平面鏡）
３４…操作ボタン
３５…対物レンズ
３６Ｌ、３６Ｒ…瞳
Ｐ…左右光軸の交差点
Ｏ…立体物[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a binocular image display device, and in particular, an image displayed on an image display element or an aerial image formed by another optical system is guided to the left and right eyes to perform binocular observation and stereoscopic image observation. The present invention relates to a small image display device that can be carried.
[0002]
[Prior art]
Conventionally, as an optical system element for guiding an image displayed on one display element to both eyes of an observer, one disclosed in Japanese Patent Laid-Open No. 9-181999 is known. This splitting element splits two optical paths that travel in different directions using a single prism.
[0003]
However, in an image display apparatus using this dividing element, if the image display element is made small, it is necessary to shorten the focal length of the optical system while ensuring eye relief. difficult.
[0004]
Also, an image display element that divides an optical path using a half mirror has been proposed as disclosed in JP-A-9-061748.
[0005]
Further, in Japanese Patent Laid-Open Nos. 51-24116 and 51-58355, left and right eye images displayed on a pair of left and right display elements are passed through left and right concave mirrors and a binocular common concave mirror. There has been proposed an image display device that can be used to observe a stereoscopic image.
[0006]
Japanese Patent Laid-Open No. 58-58517 proposes an image projection apparatus that projects an image displayed on a CRT onto a transmission screen through a projection lens and a spheroid mirror.
[0007]
Japanese Patent Application Laid-Open No. 60-138509 discloses a binocular image display device in which an image displayed on one display element is divided into two optical paths that travel in different directions by a microprism array and guided to the viewer's eyes. Proposed.
[0008]
Japanese Patent Laid-Open No. 60-256117 proposes a binocular projection observation apparatus that allows an object image projected on a screen with a single objective lens to be observed with left and right binocular eyepieces.
[0009]
In Japanese Patent Laid-Open No. 1-181814, the left and right eye images displayed on the pair of left and right display elements are passed through the left and right plane mirrors and the concave mirror common to both eyes, and the same space between the concave mirror and the observer's eyes. An image display device has been proposed in which images are superimposed at positions and the left and right images can be observed as a stereoscopic image with both eyes.
[0010]
[Problems to be solved by the invention]
In the case of splitting into the two optical paths that proceed in the different directions described above, the optical path splitting element becomes large, and when the image display device is configured, it becomes a large and heavy device. In addition, the method of dividing the optical path using the above-described half mirror has a problem that the amount of light is halved in each optical path, and a dark observation image must be observed.
[0011]
The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a binocular image display device that can be observed as a stereoscopic image or the like with both eyes and is small and portable with a small number of components. It is to be.
[0012]
[Means for Solving the Problems]
The binocular image display device of the present invention that achieves the above object includes a relay optical system that projects an image displayed on an image display element or an aerial image formed by another optical system as an object point, and the relay In an image display apparatus having an eyepiece optical system having a converging action for converging a light beam from an optical system toward an observer's eye,
The relay optical system splits a light beam emitted from an object displayed on the image display element or the aerial image into two optical paths and forms left and right exit pupils on the two optical paths. An optical system that
The eyepiece optical system guides the two optical paths divided by the relay optical system to the left and right exit pupils corresponding to the observer's eyes, and the left and right exit pupils formed by the relay optical system to the observer's eyes Having at least positive power to project to the left and right exit pupil positions corresponding to
The optical axes of the two optical paths guided from the eyepiece optical system to the left and right exit pupils corresponding to the observer's eyes are arranged so as to intersect on the observer's eyes side with respect to the eyepiece optical system. It is what.
[0013]
Hereinafter, the reason and effect | action which take the said structure in this invention are demonstrated.
[0014]
In order to construct a small-sized image display device with low power consumption, a method of enlarging a small image display element with a relay optical system and observing the image with an eyepiece optical system is preferable. However, in order to be able to observe this with both eyes, it is necessary to configure the relay optical system so as to ensure a wide exit pupil diameter that allows light to enter both eyes. In a relay optical system having a diameter, the optical system becomes large, and at the same time, aberration correction is difficult, and a clear observation image cannot be observed.
[0015]
Therefore, in the present invention, first, a relay optical system that projects an image displayed on an image display element or an aerial image formed by another optical system as an object point, and a light beam from the relay optical system are observed. In an image display apparatus having an eyepiece optical system having a convergence action that converges toward a person's eyes, the image displayed on such an image display element or an aerial image is used as an object point as a relay optical system. An optical system that divides the luminous flux emitted from the light into two optical paths and forms left and right exit pupils on the two optical paths is used.
[0016]
Since the small projection type image display device has a small display screen, if a relay optical system having a single wide exit pupil that can be observed with both eyes is used, the relay optical system becomes large and heavy. The device cannot be configured.
[0017]
In the present invention, binocular observation is possible with a simple configuration and low power consumption by an optical system that can extract two light beams corresponding to the left and right eyeballs of the observer from a common single image display element. An optical system can be provided.
[0018]
In order to realize such a small image display device, a small image display element is enlarged and projected once by a small relay optical system, and this projection image is enlarged by an eyepiece optical system, and is emitted from the relay optical system. It is preferable to project the pupil onto the exit pupil corresponding to both eyes of the observer. However, in a small relay optical system, it is difficult to supply an image to both eyes because a single wide exit pupil cannot be formed as described above.
[0019]
Therefore, in the present invention, an image displayed on a single image display element or an aerial image is used as an object point, and a light beam emitted from the object point is divided into two optical paths, and left and right exit pupils are provided on the two optical paths. And a compact image display device capable of binocular observation by emitting each light beam toward both eyes of an observer.
[0020]
Then, the optical axis of the two optical paths guided from the eyepiece optical system to the left and right exit pupils corresponding to the observer's eyes is configured to intersect the observer's eyes side with respect to the eyepiece optical system. It is observed that an image is displayed at the intersection position in front of it, and it looks as if a stereoscopic image is displayed in the air, and a display device with a strong stereoscopic effect and realism becomes possible.
[0021]
The relay optical system is preferably configured to form an image displayed on the image display element or an aerial image in the vicinity of the eyepiece optical system.
[0022]
With such a configuration, an optical surface having directional diffusivity is arranged in the vicinity of the eyepiece optical system, and the range of the left and right exit pupils by the eyepiece optical system is expanded by thickening the light beam, so that an image can be obtained with both eyes. The range that can be observed can be expanded.
[0023]
In addition, the right and left exit pupils of the relay optical system have a long ellipse to the left and right to increase the pupil diameter, and at the same time, the diffusive optical surface is diffused only in the vertical direction perpendicular to the long axis of the ellipse. By using an optical surface having an action, it is possible to widen the range that can be observed with both eyes without darkening.
[0024]
Further, it is desirable to use an eccentric reflection optical system as the relay optical system. By using such a decentered reflection optical system, it is known to construct a small optical system with less aberration.
[0025]
More specifically, the relay optical system has a prism member formed of a medium having a refractive index (n) larger than 1 (n> 1), and the prism member emits a light beam emitted from an object point. An incident surface that enters the prism, at least one reflecting surface that reflects the light beam inside the prism, an exit surface that emits the light beam outside the prism, and at least one rotationally asymmetric surface; It is desirable that at least one optical action surface is constituted by a discontinuous surface composed of at least two adjacent surfaces, and the other optical action surface is commonly arranged in at least two divided optical paths.
[0026]
When viewed from only one optical path, for example, as disclosed in Japanese Patent Laid-Open No. 2000-212440, an incident surface on which a light beam emitted from an image display element or an aerial image enters the prism, and at least one that reflects the light beam in the prism Having at least one reflecting surface and a curved surface shape that gives power to the light beam, and the curved surface shape corrects an aberration caused by decentration. This is a decentered prism configured with a rotationally asymmetric surface shape, and the other optical path has the same configuration.
[0027]
A refractive optical element such as a lens can be given power only by giving a curvature to its boundary surface. For this reason, when light rays are refracted at the boundary surface of the lens, the occurrence of chromatic aberration due to the chromatic dispersion characteristics of the refractive optical element is inevitable. As a result, another refractive optical element is generally added for the purpose of correcting chromatic aberration.
[0028]
On the other hand, reflective optical elements such as mirrors and prisms do not generate chromatic aberration in principle even if power is given to their reflecting surfaces, and it is necessary to add another optical element only for the purpose of correcting chromatic aberration. There is no. Therefore, the optical system using the reflective optical element can reduce the number of constituent elements of the optical element from the viewpoint of chromatic aberration correction, compared to the optical system using the refractive optical element.
[0029]
At the same time, since the reflection optical system using the reflection optical element folds the optical path, the optical system itself can be made smaller than the refractive optical system.
[0030]
Moreover, since the reflecting surface has a higher eccentricity error sensitivity than the refracting surface, high accuracy is required for assembly adjustment. However, among the reflective optical elements, since the relative positional relationship between the prisms is fixed, it is only necessary to control the eccentricity of the prism alone, and unnecessary assembly accuracy and adjustment man-hours are unnecessary.
[0031]
Furthermore, the prism has an entrance surface and an exit surface, which are refracting surfaces, and a reflecting surface, and has a higher degree of freedom in correcting aberrations than a mirror having only a reflecting surface. In particular, by sharing most of the desired power to the reflecting surface and reducing the power of the entrance surface and exit surface, which are refracting surfaces, the degree of freedom of aberration correction can be kept large compared to mirrors, etc. Compared with such a refractive optical element, the occurrence of chromatic aberration can be made very small. In addition, since the inside of the prism is filled with a transparent body having a refractive index higher than that of air, the optical path length can be made longer than that of air, and the optical system is more effective than lenses and mirrors arranged in the air. Thinning and miniaturization are possible.
[0032]
Further, an optical system such as an observation optical system is required to have good imaging performance to the periphery as well as the center performance. In the case of a general coaxial optical system, the sign of the off-axis light beam height is reversed before and after the stop, so that the symmetry of the optical element with respect to the stop is broken, and the off-axis aberration is deteriorated. Therefore, it is common to correct the off-axis aberration by sufficiently satisfying the symmetry with respect to the stop by arranging the refracting surface across the stop.
[0033]
Therefore, there is an incident surface on which the light beam emitted from the image display element or the aerial image enters the prism, at least one reflecting surface that reflects the light beam inside the prism, and an emission surface that emits the light beam outside the prism. The decentered prism having at least one reflecting surface having a curved surface shape that gives power to the light flux, and the curved surface shape correcting the aberration caused by decentering is a relay optical system. In combination with an eyepiece optical system that is configured with a rotationally asymmetric curved surface that gives power to the luminous flux and corrects aberrations caused by decentration, by correcting each other decentration aberrations, not only the center The off-axis aberration can be corrected well. If only one decentered prism or only one eyepiece optical system is arranged, it is difficult to completely correct decentration aberrations.
[0034]
Therefore, in the present invention, by constructing a part of the surface of such an eccentric prism as a discontinuous surface comprising at least two adjacent surfaces, the optical path splitting action has been successfully provided to the eccentric prism of the relay optical system. Is. This discontinuous surface divides at least two luminous fluxes emitted from the image display element or the aerial image, and individually corrects aberrations by at least two optical action surfaces, and at the same time, at any optical axis interval and at any angle. It is possible to divide the optical axis.
[0035]
As an eccentric prism used in such a relay optical system, an incident surface for entering light into the prism, one or more reflecting surfaces for reflecting the light within the prism, and an exit surface for emitting the reflected light out of the prism Any of various known ones having a reflection count of 1 or more can be used. However, even in that case, in order to provide an optical path dividing action, a part of the surface of the decentered prism is configured as a discontinuous surface composed of at least two adjacent surfaces.
[0036]
As an example of such a decentered prism, there are two reflecting surfaces, which are composed of an incident surface, a first reflecting surface, a second reflecting surface, and an exit surface, and the optical path connecting the incident surface and the first reflecting surface is the second reflecting surface. Some optical paths connecting the surface and the exit surface intersect in the prism.
[0037]
As another example of such an eccentric prism, it is provided with three reflecting surfaces, and the third reflecting surface among them is formed by a surface that also serves as an incident surface on which light from an image display element or an aerial image is incident, In some cases, the first reflecting surface is formed as a surface also serving as an exit surface.
[0038]
Furthermore, a second prism that includes two reflecting surfaces and includes an incident prism, a first reflecting surface that also serves as an exit surface, and a second reflecting surface, or two reflecting surfaces that also serve as an incident surface. An eccentric prism composed of a reflecting surface, a first reflecting surface, and an exit surface can be exemplified.
[0039]
More preferably, the decentered prism is formed of a free-form surface having only one plane of symmetry, and each plane constituting the prism preferably has a plane of symmetry within substantially the same plane. With this configuration, it is possible to have a relatively large effective diameter in the direction orthogonal to the symmetry plane, and a large exit pupil diameter in the horizontal direction with an aspect ratio of 2 or more.
[0040]
Here, the free-form surface is a free-form surface defined by, for example, the equation (a) of US Pat. No. 6,124,989 (Japanese Patent Laid-Open No. 2000-66105), and the Z-axis of the definition equation is free. It becomes the axis of the curved surface.
[0041]
Further, in the binocular image display device of the present invention, the image projected by the relay optical system can be supplied to both eyes of the observer without waste by the action of the eyepiece optical system, and at the same time, the divided optical paths This makes it possible to observe with both eyes. By dividing the optical path, the left and right exit pupils of the image display device can be arranged adjacent to each other, and an image display device that does not cause vignetting even if the observer moves the eyeball somewhat can be provided.
[0042]
Further, when the image display apparatus is configured in this manner, the ocular optical system is inclined and is particularly inclined (especially when the eyepiece optical system is a reflective optical system), and thus large decentration aberrations occur. In particular, decentration aberrations in pupil projection cause pupil aberrations, resulting in image distortion and a narrowed observation area.
[0043]
Therefore, the ocular optical system is configured to have one or more rotationally asymmetric surfaces for correcting aberrations caused by such decentering, so that not only the center but also off-axis aberrations can be corrected well. Become.
[0044]
The rotationally asymmetric curved surface shape is not limited, but it is desirable to use a free curved surface.
[0045]
Here, it is preferable that the eyepiece optical system has at least a reflecting action such as a concave mirror and a Fresnel reflecting surface. The reflective optical element does not generate chromatic aberration in principle even if the reflecting surface is given power, and it is not necessary to add another optical element only for the purpose of correcting the chromatic aberration. Therefore, when a reflective optical system having a reflecting action is used as the eyepiece optical system, the number of constituent elements of the optical element can be reduced from the viewpoint of correcting chromatic aberration as compared with an optical system using a refractive optical element.
[0046]
At the same time, since the reflection optical system folds the optical path, the optical system itself can be made smaller than the refractive optical system.
[0047]
Of course, the eyepiece optical system may have a refracting action such as a transmissive lens and a Fresnel transmissive surface. Further, it may have a diffractive action such as a transmissive diffractive optical element, a transmissive hologram element, a reflective diffractive optical element, or a reflective hologram element.
[0048]
In particular, a thin eyepiece optical system can be configured by manufacturing the eyepiece optical system with a diffractive optical element, a hologram element, a Fresnel lens, a Fresnel reflection surface, and the like.
[0049]
In addition, when an eyepiece optical system is composed of a diffractive optical element and a hologram element, the right and left emission can be given directivity diffusivity on the surface, and the light beam passing through the eyepiece optical system can be thickened to observe an image. The range of the pupil can be enlarged.
[0050]
As described above, an image is displayed on a single image display element, or an aerial image is formed by another optical system, and the relay optical system correspondingly displays an image or aerial image displayed on the image display element. This is a case where the light beam emitted from the object point is divided into two optical paths as an object point, and the optical system forms left and right exit pupils on the two optical paths. A relay optical system that projects an image displayed on the element or an aerial image formed by another optical system as an object point, and a convergence function that converges a light beam from the relay optical system toward an observer's eye In the image display device having the eyepiece optical system, the image display element includes a pair of image display elements, the aerial image includes a pair of aerial images formed in parallel, and the relay optical system includes: Displayed on the image display element A pair of images or a pair of aerial images arranged in parallel with each other as an object point, the light beams emitted from these object points are guided to separate optical paths, and the optical system forms left and right exit pupils on the two optical paths. The eyepiece optical system guides the two optical paths that have passed through the relay optical system to the left and right exit pupils corresponding to the observer's eyes, and the left and right exit pupils formed by the relay optical system to the observer's eyes. The optical axes of the two optical paths that have at least positive power to project to the corresponding left and right exit pupil positions and are guided from the eyepiece optical system to the left and right exit pupils corresponding to the observer's eyes are obtained from the eyepiece optical system. The above discussion is true even if the observer is arranged so as to intersect on both eyes.
[0051]
In this case, the relay optical system is preferably configured to form an image displayed on the pair of image display elements or an aerial image formed in parallel in the vicinity of the eyepiece optical system.
[0052]
With such a configuration, an optical surface having directional diffusivity is arranged in the vicinity of the eyepiece optical system, and the range of the left and right exit pupils by the eyepiece optical system is expanded by thickening the light beam, so that an image can be obtained with both eyes. The range that can be observed can be expanded.
[0053]
In addition, the right and left exit pupils of the relay optical system have a long ellipse to the left and right to increase the pupil diameter, and at the same time, the diffusive optical surface is diffused only in the vertical direction perpendicular to the long axis of the ellipse. By using an optical surface having an action, it is possible to widen the range that can be observed with both eyes without darkening.
[0054]
Further, it is desirable to use an eccentric reflection optical system as the relay optical system. By using such a decentered reflection optical system, it is known to construct a small optical system with less aberration.
[0055]
More specifically, the relay optical system has a pair of decentered prisms formed of a medium having a refractive index (n) larger than 1 (n> 1), and each decentered prism has a corresponding image display element or An incident surface for entering the light beam emitted from the aerial image into the prism; at least one reflecting surface for reflecting the light beam within the prism; and an exit surface for emitting the light beam out of the prism. It is desirable that the reflecting surface be a rotationally asymmetric surface that gives power to the light beam.
[0056]
As an example of such an eccentric prism, similarly to the case described above, it includes two reflecting surfaces, and includes an incident surface, a first reflecting surface, a second reflecting surface, and an exit surface, and the incident surface, the first reflecting surface, and the like. There is an optical path that connects the second reflecting surface and the exit surface in the prism.
[0057]
As another example of such an eccentric prism, it is provided with three reflecting surfaces, and the third reflecting surface among them is formed by a surface that also serves as an incident surface on which light from an image display element or an aerial image is incident, In some cases, the first reflecting surface is formed as a surface also serving as an exit surface.
[0058]
Furthermore, a second prism that includes two reflecting surfaces and includes an incident prism, a first reflecting surface that also serves as an exit surface, and a second reflecting surface, or two reflecting surfaces that also serve as an incident surface. An eccentric prism composed of a reflecting surface, a first reflecting surface, and an exit surface can be exemplified.
[0059]
More preferably, the decentered prism is formed of a free-form surface having only one plane of symmetry, and each plane constituting the prism preferably has a plane of symmetry within substantially the same plane. With this configuration, it is possible to have a relatively large effective diameter in the direction orthogonal to the symmetry plane, and a large exit pupil diameter in the horizontal direction with an aspect ratio of 2 or more.
[0060]
The form of the eyepiece optical system is the same as that described above.
[0061]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the binocular image display device of the present invention will be described below.
[0062]
Before describing specific numerical examples 1 to 3, examples of the basic form and usage of the binocular image display apparatus of the present invention will be described.
[0063]
As shown in FIG. 1, the basic form of the binocular image display device of the present invention is that a relay optical system 31 is arranged on a main body 30, and a single or a pair of image display elements are arranged at the position of the object. An eyepiece optical system 32 having a positive power is disposed on the exit side of the relay optical system 31, and light rays emitted from the image display element travel along the two optical axes 2 </ b> L and 2 </ b> R via the relay optical system 31. 32, left and right exit pupils 1L and 1R are formed in the vicinity of the observer's eyes. At this time, the left and right optical axes 2L, 2R are arranged so as to intersect at a point P on the exit pupil 1L, 1R side in front of the eyepiece optical system 32.
[0064]
In this way, the light beam from the image display element is guided by the relay optical system 31 along the left and right optical axes 2L and 2R, and projected onto the left and right exit pupils 1L and 1R of the image display device, so that the illumination light can be projected. The image can be projected onto both eyes without waste, and a bright and efficient image with a strong stereoscopic effect and presence can be enlarged and displayed.
[0065]
In the case of FIG. 1, the left and right optical axes 2L and 2R emitted from the relay optical system 31 are folded back by the reflecting surface 33 and guided to the observer's eyes by the transmission type (refractive type) eyepiece optical system 32. Has been. In the case of FIG. 1, the operation button 34 is disposed on the main body 30 of the display device in front of the relay optical system 31 when viewed from the observer side. With this arrangement, it is possible to avoid the problem of blocking the image every time the button is operated without blocking the light path by the hand operating the operation button 34.
[0066]
Further, the function of the eyepiece optical system 32 makes it possible to supply the left and right images projected by the relay optical system 31 to the eyes of the observer without waste.
[0067]
The right and left images of the image displayed on the image display element along the left and right optical axes 2L and 2R by the relay optical system 31 are formed in the vicinity of the eyepiece optical system 32.
[0068]
By the way, as a form of the relay optical system 31, as shown in FIG. 2, the relay optical system 31 is composed of a single decentered prism 10, and as shown in FIG. 3, it is composed of a pair of left and right decentered prisms 10L and 10R. There is a case. In the case of the single decentered prism 10 in the case of FIG. 2, as schematically shown in FIG. 4 as an example, it has an entrance surface 11, an exit surface 14, and two internal reflection surfaces 12 and 13, and an image. The optical axes (axial principal rays) 2L, 2R emitted from the display element 3 are configured to substantially intersect in the optical system, and the exit surface 14 is configured by a discontinuous surface composed of two adjacent surfaces 14L, 14R. is doing. Of course, one or more of the other optical surfaces 11 to 13 may be formed of a discontinuous surface composed of such two surfaces.
[0069]
As described above, the left and right optical axes 2L and 2R that are incident on the left and right exit pupils 1L and 1R are formed in front of the eyepiece optical system 32 in the vicinity of the eyepiece optical system 32. By intersecting at the point P, it is observed as if the stereoscopic image is floating and displayed in the air at the intersection position P, and an image having a strong stereoscopic effect and a realistic feeling can be observed.
[0070]
As shown in FIG. 2, the relay optical system 31 includes at least one optical action surface (reflection surface or refracting surface) composed of a single decentered prism 10 having a discontinuous surface composed of two adjacent surfaces. As an image display element, a single image display element is arranged on the object plane to display a single image.
[0071]
As shown in FIG. 3, when the same pair of left and right decentered prisms 10L and 10R are used as the relay optical system 31, separate image display elements are arranged on the object surfaces of the decentered prisms 10L and 10R, respectively. Alternatively, a single image display element may be arranged in common on the left and right sides, and the image display element may be divided into two to display the same image in each region.
[0072]
By the way, the eyepiece optical system 32 disposed in the vicinity of the position where the images of the left and right eye images are formed by the relay optical system 31 is suppressed within a range in which the left and right exit pupils 1L and 1R are not mixed (overlapped). By disposing a diffusive optical surface having directivity and thickening the light flux toward the exit pupils 1L and 1R, the range of the exit pupils 1L and 1R is expanded to expand the range in which an image can be observed with both eyes. Can be.
[0073]
In this case, the shapes of the left and right exit pupils 1L and 1R of the relay optical system 31 imaged at the positions of the exit pupils 1L and 1R by the eyepiece optical system 32 when there is no diffusibility are as shown in FIG. It is desirable that the left and right elliptical exit pupils 1L and 1R be large in the left and right ellipses, and the diffusive optical surface disposed in the eyepiece optical system 32 is as shown in FIG. If the surface has a diffusing action in the up and down direction and hardly has a diffusing action in the left and right direction as shown in FIG. 6 (b), it will not be darkened without wasting the amount of light, and the exit pupils 1L and 1R The range in which the image can be observed with both eyes is expanded by expanding the range vertically and horizontally.
[0074]
Since the optical element constituting the eyepiece optical system 32 of the present invention is configured using a rotationally asymmetric surface, in particular, an axis that exits the object center, passes through the iris center of the observer, and reaches the fundus center. In the case of a decentered optical system in which the upper principal ray is decentered with respect to the eyepiece optical system 32, by constructing the eyepiece optical system 32 with a rotationally asymmetric surface, the trapezoidal distortion of the image caused by the decentering or the tilt of the image surface It is possible to correct decentration aberrations such as the above. Further, when the relay optical system 31 is configured by a decentered prism optical system, it is possible to share the correction of decentration aberrations with the relay optical system 31, which is more preferable.
[0075]
Next, the relay optical system 31 will be described. For the relay optical system 31 according to the present invention, various decentered prism optical systems having a number of internal reflections of one or more, which have already been proposed by the present inventors, can be used. Among them, as a typical example, it includes two reflecting surfaces like the decentered prisms of Examples 1 to 3 described later, and includes an incident surface, a first reflecting surface, a second reflecting surface, and an exit surface. An optical path connecting the incident surface and the first reflecting surface intersects with the optical path connecting the second reflecting surface and the exit surface in the prism.
[0076]
The decentered prism having such a shape has a high degree of freedom in correcting aberrations and generates less aberrations. Further, since the arrangement of the two reflecting surfaces is highly symmetric, the aberration generated on the two reflecting surfaces is corrected between the two reflecting surfaces, and the occurrence of aberration is small. In addition, because the optical path forms a crossed optical path in the prism, the optical path length can be made longer compared to a prism with a structure that simply folds the optical path, and the prism is downsized for the length of the optical path length. can do.
[0077]
Further, as shown in FIG. 21A, the first surface 11 facing the image display element 3, the second surface 12 facing the eyepiece optical system 32, and the third surface 13 are formed. The light rays from the image display element 3 refracted and incident on the prism are totally reflected by the second surface 12, the reflected light is reflected by the third surface 13, and this reflected light is now totally reflected by the first surface 11. The reflected light is then refracted by the second surface 12 and exits from the prism. The first surface 11 exits from the incident surface and the third reflecting surface, and the second surface 12 exits from the first reflecting surface. An eccentric prism 10 that also serves as a surface and in which the light beam makes one rotation in the prism may be used. Since the decentered prism 10 has three reflecting surfaces, it is possible to disperse power over three reflecting surfaces and reduce the occurrence of aberrations. Further, since the optical paths intersect in the prism, the optical path length can be made longer than that of a prism having a structure in which the optical path is simply folded.
[0078]
Further, as shown in FIG. 21B, the first surface 11 facing the image display element 3, the second surface 12 facing the eyepiece optical system 32, and the third surface 13 are formed. The light beam from the image display element 3 refracted and incident on the prism is totally reflected by the second surface 12, the reflected light is reflected by the third surface 13, and the reflected light is now refracted by the second surface 12. The second surface 12 may be an eccentric prism 10 that serves as both the first reflecting surface and the exit surface. This decentered prism 10 which serves both as a first reflecting surface and an exit surface is designed to bend the light rays largely at the first reflecting surface, and the second reflecting surface reflects the light rays to the exit surface with a small bending angle. It is possible to reduce the thickness of the optical system in the direction of the emitted light.
[0079]
Further, as shown in FIG. 21C, the first surface 11 facing the image display element 3, the second surface 12 facing the eyepiece optical system 32, and the third surface 13 are formed. The light beam from the image display element 3 refracted and incident on the prism is reflected by the third surface 13, and the reflected light is totally reflected by the first surface 11, and the reflected light is refracted by the second surface 12. The first surface 11 may be an eccentric prism 10 that serves both as an incident surface and a second reflecting surface. The decentered prism 10 that serves as both the second reflecting surface and the incident surface is configured to bend the light beam largely at the second reflecting surface, and the first reflecting surface reflects the light beam to the second reflecting surface with a small bending angle. It is possible to reduce the thickness of the prism optical system in the incident light direction.
[0080]
When any of the above decentered prisms 10 is composed of a single decentered prism 10 as shown in FIG. 2, at least one optical action surface (reflecting surface or refracting surface) is not formed of two adjacent surfaces. By constituting as a continuous surface, the light beam from the image display element 3 is divided into two optical paths.
[0081]
The binocular image display device of the present invention is provided with a mechanism for opening and closing the eyepiece optical system 32 and the reflecting surface 33 of FIGS. 1 to 3 from the main body 30 of the display device, and is stored in a pocket or the like when carried. It can be configured. At this time, if a function of cutting off the power supply is added, the power saving effect is high.
[0082]
Further, the present invention is not limited to such a portable usage mode, and can be configured as a hand-held viewer type as shown in FIG.
[0083]
Next, numerical examples 1 to 3 of the optical system used in the binocular image display device of the present invention will be described.
[0084]
Although the configuration parameters of Examples 1 to 3 will be described later, the coordinate system is between two left and right exit pupils 1L and 1R (FIG. 1) (observer pupil) as shown in FIGS. A plane that passes through the center and is perpendicular to a straight line connecting the centers of the exit pupils 1L and 1R and that forms a symmetry plane of the optical system is defined as a YZ plane, and travels from the center of the exit pupils 1L and 1R toward the eyepiece optical system 32. The direction is the Z-axis positive direction, the direction orthogonal to the Z-axis direction is the Y-axis direction, the direction toward the image display element 3 side is the Y-axis negative direction, and the direction orthogonal to the YZ plane is the X-axis Direction, and the Y-axis, Z-axis and the X-axis direction constituting the right-handed orthogonal coordinate system are defined as the X-axis positive direction. The origin of the optical system is set as the top position of the surface of the eyepiece optical system 32 on the exit pupil 1L, 1R side.
[0085]
For the eccentric surface, the amount of eccentricity from the center of the origin of the optical system to the top position of the surface (X, Y, and Z directions are X, Y, and Z, respectively) and the center axis of the surface (free For curved surfaces, the Z-axis in the above equation (a), and for aspherical surfaces, the Z-axis in the later-described equation (b))) is tilted around the X-axis, Y-axis, and Z-axis (α, β respectively) , Γ (°)). In this case, positive α and β mean counterclockwise rotation with respect to the positive direction of each axis, and positive γ means clockwise rotation with respect to the positive direction of the Z axis. Note that the α, β, and γ rotations of the central axis of the surface are performed by first rotating the central axis of the surface and its XYZ orthogonal coordinate system by α counterclockwise around the X axis, and then rotating the rotation. The center axis of the surface is rotated β counterclockwise around the Y axis of the new coordinate system, and the coordinate system rotated once is also rotated β counterclockwise around the Y axis and then rotated twice. The center axis of the surface is rotated γ clockwise around the Z axis of the new coordinate system.
[0086]
Further, the shape of the surface of the free-form surface used in the present invention is a free-form surface defined by, for example, the equation (a) of US Pat. No. 6,124,989 (Japanese Patent Laid-Open No. 2000-66105). The Z-axis is the axis of the free-form surface.
[0087]
An aspherical surface is a rotationally symmetric aspherical surface given by the following definition.
[0088]

However, Z is an optical axis (axial principal ray) with the light traveling direction being positive, and y is a direction perpendicular to the optical axis. Here, R is a paraxial radius of curvature, K is a conic constant, A, B, C, D,... Are fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients, respectively. The Z axis of this defining formula is the axis of a rotationally symmetric aspherical surface.
[0089]
Note that terms relating to free-form surfaces and aspheric surfaces for which no data is described are zero. The refractive index is shown for d-line (wavelength 587.56 nm).
The unit of length is mm.
[0090]
Numerical examples 1 to 3 shown below are expressed by back ray tracing from the one exit pupil 1L to the image display elements 3 and 3L.
[0091]
Example 1 has a one-sided pupil diameter of 40 mm and an upper and lower side of 15 mm, and an observation image is formed on the eyepiece optical system 32 having a horizontal size of 55 mm and a vertical size of 41.25 mm, 400 mm forward from the pupil position, and the left and right optical axes are inward. It exits from the eyepiece optical system 32 with an angle, and its inward angle intersects the eyepiece optical system 32 side from the pupil position at a position of 320 mm. As the image display element 3, a display element of 8.94 mm × 6.71 mm is used.
[0092]
8 is an optical path diagram of one optical system projected onto the YZ plane of the first embodiment, FIG. 9 is an optical path diagram projected onto the XZ plane, and FIG. 10 is an optical system on both sides projected onto the XZ plane. FIG. 11 shows an enlarged view of the vicinity of the decentered prism 10 of the image display element 3 and the relay optical system 31 in FIG.
[0093]
The numerical data described later is from the left exit pupil 1L to the image display element 3, and the optical data from the right exit pupil 1R to the image display element 3 is plane-symmetric with the YZ plane as the symmetry plane. It will be arranged at the position of.
[0094]
In this embodiment, the fourth surface 14 (five surfaces in the numerical data) of the decentering prism 10 constituting the relay optical system 31 is a discontinuous surface that is symmetrical with respect to the YZ plane, and is emitted on the left side. Only the surface shape of one surface 14L involved in the formation of the pupil 1L is shown. The surface 14L is provided on the negative side of the X axis from the YZ plane, and the other surface 14R that is plane-symmetric with respect to the positive side of the X axis is provided from the YZ plane (FIG. 11). By forming the fourth surface 14 as a discontinuous surface composed of two optical surfaces 14L and 14R that are symmetrical with respect to the symmetry plane, 75 mm can be obtained around the symmetry surface (YZ surface) of the optical system of the present embodiment. An optical system having left and right exit pupils 1L, 1R having a pupil diameter of 40 mm apart and 15 mm above and below can be configured.
[0095]
The optical system of Example 1 is an optical system for a binocular image display device corresponding to the form of FIG. 2 as shown in FIGS. 8 to 11, and an eyepiece optical system 32 facing the exit pupil 1L (1R) is The exit pupil 1L (1R) side surface is a Fresnel transmission surface, and the opposite surface is a flat Fresnel lens. A reflection surface (plane mirror) 33 for returning the optical path is disposed on the incident side. Thus, the relay optical system 31 is arranged. The relay optical system 31 includes a decentered prism 10 facing the image display element 3, and the decentered prism 10 of this embodiment includes a first surface 11 facing the image display element 3 and a fourth surface facing the reflecting surface 33. 14 and the second surface 12 and the third surface 13 of the two reflecting surfaces arranged between the first surface 11 and the fourth surface 14, and as described above, the fourth surface 14 is symmetrical with the optical system. It consists of two surfaces 14L and 14R that constitute a discontinuous plane that is plane-symmetric with respect to the plane (YZ plane).
[0096]
In this embodiment, the display light from the image display element 3 is refracted by the first surface 11 of the decentered prism 10 and enters the prism, and the internal reflection is repeated between the second surface 12 and the third surface 13, and the fourth surface. The two surfaces 14L and 14R are refracted as light beams along different optical paths and emitted out of the prism. The two light beams are folded back by the reflecting surface 33 and displayed on the Fresnel lens surface of the eyepiece optical system 32. The enlarged images for the left and right eyes of the element 3 are formed as double images, and the light beams refracted by the eyepiece optical system 32 converge on the left and right exit pupils 1L and 1R, respectively. At that time, since the left and right optical axes 2L and 2R intersect at a point P of 320 mm from the position of the exit pupils 1L and 1R to the eyepiece optical system 32 side, an image is formed on the Fresnel lens surface of the eyepiece optical system 32. The enlarged images for the left and right eyes are fused in the vicinity of the point P, and a display image can be seen as if it is displayed as if it is floating in the air.
[0097]
In this embodiment, a lenticular sheet having diffusivity in the vertical direction is arranged near the plane of the eyepiece optical system 32 (three surfaces in the numerical data), and the pupil is enlarged only in the vertical direction for wider observation. A range can be secured.
[0098]
In this embodiment, all of the first surface 11 to the fourth surface 14 of the decentering prism 10 are free-form surfaces, and the Fresnel transmission surface of the Fresnel lens of the eyepiece optical system 32 is an aspheric surface.
[0099]
In Example 2, the unilateral pupil diameter is 15 mm wide and 10 mm vertically, and the observation image is formed on the eyepiece optical system 32 having a horizontal size of 55 mm and a vertical size of 41.25 mm, 400 mm forward from the pupil position, and the left and right optical axes are inward. It exits from the eyepiece optical system 32 with an angle, and its inward angle intersects the eyepiece optical system 32 side from the pupil position at a position of 320 mm. As the left and right image display elements 3L and 3R, display elements of 8.94 mm × 6.71 mm are used.
[0100]
FIG. 12 is an optical path diagram of only the principal ray of one optical system projected onto the YZ plane of Example 2, FIG. 13 is a similar optical path diagram projected onto the XZ plane, and FIG. 14 is an XZ plane. The same optical path diagram of the projected optical system on both sides is shown.
[0101]
The numerical data described later is from the left exit pupil 1L to the image display element 3L, and the optical data from the right exit pupil 1R to the image display element 3R is plane-symmetric with the YZ plane as the symmetry plane. It will be arranged at the position of.
[0102]
The optical system of Example 2 is an optical system for a binocular image display device corresponding to the form of FIG. 3 as shown in FIGS. 12 to 14, and the relay optical system 31 has a YZ plane as a symmetry plane. This is an example in which a pair of plane-symmetric decentering prisms 10L and 10R are used, and left and right image display elements 3L and 3R are arranged facing each incident surface 11.
[0103]
In the optical system of this embodiment, as shown in FIGS. 12 to 14, the eyepiece optical system 32 facing the exit pupils 1L and 1R has a Fresnel transmission surface on the exit pupil 1L and 1R side and a plane on the opposite side. The reflecting surface (plane mirror) 33 for returning the optical path is disposed on the incident side, and the relay optical system 31 including the pair of decentering prisms 10L and 10R is disposed facing the reflecting surface 33. . The decentered prisms 10L and 10R of this embodiment include a first surface 11 facing the image display elements 3L and 3R, a fourth surface 14 facing the reflecting surface 33, and between the first surface 11 and the fourth surface 14, respectively. The decentering prisms 10L and 10R are plane-symmetric with respect to the symmetry plane (YZ plane) of the optical system as described above. It has a shape.
[0104]
In this embodiment, left and right eye images are displayed on the left and right image display elements 3L and 3R, and the left and right decentering prisms 10L and 10R display the left and right image display elements 3L and 3R near the common eyepiece optical system 32. An image is projected, and left and right eye images are displayed on the left and right eyes located at the exit pupils 1L and 1R.
[0105]
That is, the display light from the left and right image display elements 3L and 3R is refracted by the first surface 11 of the left and right decentered prisms 10L and 10R and enters the prism, and is internally reflected by the second surface 12 and the third surface 13. Repeatedly, the light is refracted on the fourth surface 14 and exits from the prism. The two light beams are folded back by the reflecting surface 33, and the left and right eyes of the left and right image display elements 3L and 3R on the Fresnel lens surface of the eyepiece optical system 32. For example, the enlarged light image is formed as a double image, and the light beams refracted by the eyepiece optical system 32 converge to the left and right exit pupils 1L and 1R, respectively. At that time, since the left and right optical axes 2L and 2R intersect at a point P of 320 mm from the position of the exit pupils 1L and 1R to the eyepiece optical system 32 side, an image is formed on the Fresnel lens surface of the eyepiece optical system 32. The enlarged images for the left and right eyes are fused in the vicinity of the point P, and a display image can be seen as if it is displayed as if it is floating in the air.
[0106]
Also in this embodiment, a lenticular sheet having diffusivity in the vertical direction is arranged near the plane (three surfaces in the numerical data) of the eyepiece optical system 32, and the pupil is enlarged only in the vertical direction. An observation range can be secured.
[0107]
In this embodiment, all of the first surface 11 to the fourth surface 14 of the decentering prisms 10L and 10R are free-form surfaces, and the Fresnel transmission surface of the Fresnel lens of the eyepiece optical system 32 is an aspheric surface.
[0108]
In Example 3, the unilateral pupil diameter is 10 mm, the observation image is formed on the eyepiece optical system 32 having a horizontal size of 55 mm and a vertical size of 41.25 mm, 400 mm forward from the pupil position, and the left and right optical axes have inward angles. It exits from the eyepiece optical system 32, and its inward angle intersects the eyepiece optical system 32 side from the pupil position at a position of 320 mm. As the image display element 3, a display element of 8.94 mm × 6.71 mm is used.
[0109]
FIG. 15 is an optical path diagram of only the principal ray of one optical system projected onto the YZ plane of Example 3, FIG. 16 is a similar optical path diagram projected onto the XZ plane, and FIG. 17 is an XZ plane. FIG. 18 is an enlarged view of the vicinity of the eccentric prism 10 of the image display element 3 and the relay optical system 31 in FIG.
[0110]
The numerical data described later is from the left exit pupil 1L to the image display element 3, and the optical data from the right exit pupil 1R to the image display element 3 is plane-symmetric with the YZ plane as the symmetry plane. It will be arranged at the position of.
[0111]
In this embodiment, the eyepiece optical system 32 is different from the first embodiment in that the exit pupil 1L (1R) side surface is a free-form transmission surface 21, and the opposite surface is a Fresnel reflection surface 22. In this example, the reflecting surface 33 for turning back the optical path is omitted, and the fourth surface 14 (five surfaces in the numerical data) of the decentered prism 10 constituting the relay optical system 31 is a surface with the YZ plane as a symmetry plane. Only the one surface 14L, which is formed of a symmetrical discontinuous surface and is involved in the formation of the left exit pupil 1L, is shown. The surface 14L is provided on the negative side of the X axis from the YZ plane, and the other surface 14R that is plane-symmetrical to the YZ plane is provided on the positive side of the X axis (FIG. 18). By forming the fourth surface 14 as a discontinuous surface composed of two optical surfaces 14L and 14R that are symmetrical with respect to the symmetry plane, 75 mm can be obtained around the symmetry surface (YZ surface) of the optical system of the present embodiment. An optical system having left and right exit pupils 1L and 1R having a pupil diameter of 10 mm can be configured.
[0112]
As shown in FIGS. 15 to 18, the eyepiece optical system 32 facing the exit pupil 1L (1R) is opposite to the transmission surface 21 having a free-form surface on the exit pupil 1L (1R) side. The side surface is composed of the Fresnel reflecting mirror 20 including the Fresnel reflecting surface 22, and the relay optical system 31 is disposed on the reflecting side. The relay optical system 31 includes a decentered prism 10 facing the image display element 3, and the decentered prism 10 of this embodiment includes a first surface 11 facing the image display element 3 and a fourth surface facing the reflecting surface 33. 14 and the second surface 12 and the third surface 13 of the two reflecting surfaces arranged between the first surface 11 and the fourth surface 14, and as described above, the fourth surface 14 is symmetrical with the optical system. It consists of two surfaces 14L and 14R that constitute a discontinuous plane that is plane-symmetric with respect to the plane (YZ plane).
[0113]
In this embodiment, the display light from the image display element 3 is refracted by the first surface 11 of the decentered prism 10 and enters the prism, and the internal reflection is repeated between the second surface 12 and the third surface 13, and the fourth surface. The two surfaces 14L and 14R are refracted as light beams along separate optical paths and emitted out of the prism. The two light beams are projected on the transmission surface 21 of the Fresnel reflector 20 of the eyepiece optical system 32. The left and right eye enlarged images are formed as double images, and the light beams reflected by the eyepiece optical system 32 converge to the left and right exit pupils 1L and 1R, respectively. At that time, since the left and right optical axes 2L and 2R intersect at a point P of 320 mm from the position of the exit pupils 1L and 1R to the eyepiece optical system 32 side, an image is formed on the transmission surface 21 of the Fresnel reflector 20. The enlarged images for the left and right eyes are fused in the vicinity of the point P, and a display image can be seen as if it is displayed as if it is floating in the air.
[0114]
In this embodiment, a free curved surface is used for all of the first surface 11 to the fourth surface 14 of the eccentric prism 10, a free curved surface is used for the transmitting surface 21 of the Fresnel reflecting mirror 20, and the Fresnel of the Fresnel reflecting mirror 20. The reflecting surface 22 is an aspherical surface.
[0115]
The numerical data of each example is shown below. In the table below, “FFS” is a free-form surface, “ASS” is an aspheric surface, “RE” is a reflective surface, “FR” is a Fresnel surface, and “EIM” is a connection. Each image plane is shown.
[0116]

[0117]

[0118]

[0119]
The lateral aberration of the optical system on one side of Example 1 is shown in FIG. In this lateral aberration diagram, the numbers shown in parentheses represent (horizontal field angle, vertical field angle), and represent lateral aberration at that field angle.
[0120]
In the above description, the binocular image display device of the present invention is an apparatus for magnifying and observing an image displayed on one or two image display elements 3, 3L, 3R in the air with both eyes. However, instead of this, it may be configured as a binocular image display device that magnifies and observes an aerial image formed by another optical system by fusing it in the air with both eyes. FIG. 20 shows an example in which the binocular entity observation apparatus is configured using the configuration shown in FIG. The three-dimensional object O passes through an objective lens 35 having left and right pupils 36L and 36R, and is formed as a left and right aerial image on the same image plane 3 ′. The left and right aerial images pass through, for example, the eyepiece optical system 32 through the optical system of the present invention including the relay optical system 31 including the decentered prism 10 and the eyepiece optical system 32 as shown in the first embodiment. Since the images are superimposed on each other and the respective light beams are separately incident on the left and right exit pupils 1L and 1R, an enlarged stereoscopic image of the three-dimensional object O is observed by positioning both eyes on the exit pupils 1L and 1R. Will be able to.
[0121]
As the decentered prism optical system used for the relay optical system of the binocular image display device of the present invention, the type used in the above-described Examples 1 to 3 and the type having the number of internal reflections of 2 to 3 shown in FIG. The optical system is not limited to a prism, and other types of decentered prisms or combinations of these decentered prisms can be used.
[0122]
The binocular image display device of the present invention described above can be configured as follows, for example.
[0123]
[1] A relay optical system that projects an image displayed on an image display element or an aerial image formed by another optical system as an object point, and a light beam from the relay optical system toward an observer's eye In an image display device having an eyepiece optical system having a convergence action that converges in
The relay optical system splits a light beam emitted from an object displayed on the image display element or the aerial image into two optical paths and forms left and right exit pupils on the two optical paths. An optical system that
The eyepiece optical system guides the two optical paths divided by the relay optical system to the left and right exit pupils corresponding to the observer's eyes, and the left and right exit pupils formed by the relay optical system to the observer's eyes Having at least positive power to project to the left and right exit pupil positions corresponding to
The optical axes of the two optical paths guided from the eyepiece optical system to the left and right exit pupils corresponding to the observer's eyes are arranged so as to intersect on the observer's eyes side with respect to the eyepiece optical system. A binocular image display device.
[0124]
[2] The relay optical system is configured to form an image displayed on the image display element or an aerial image formed by another optical system in the vicinity of the eyepiece optical system. 2. The binocular image display device according to 1 above, wherein
[0125]
[3] The binocular image display device according to 2 above, wherein an optical surface having directional diffusivity is disposed in the vicinity of the eyepiece optical system.
[0126]
[4] The shape of each of the left and right exit pupils by the relay optical system is an ellipse that is long to the left and right, and the optical surface having directional diffusibility has a diffusing action only in the vertical direction perpendicular to the long axis of the ellipse. 4. The binocular image display device according to 3 above, which is an optical surface.
[0127]
[5] The relay optical system has a decentered prism formed of a medium having a refractive index (n) larger than 1 (n> 1), and the decentered prism prisms a light beam emitted from the object point. A light incident surface, at least one reflecting surface for reflecting the light beam inside the prism, an exit surface for emitting the light beam outside the prism, and at least one rotationally asymmetric surface, One optical action surface is composed of a discontinuous surface composed of at least two adjacent surfaces, and the other optical action surface is commonly arranged in at least two divided optical paths. The binocular image display device according to any one of 4.
[0128]
[6] The decentered prism includes two reflecting surfaces, and includes an incident surface, a first reflecting surface, a second reflecting surface, and an emitting surface, and an optical path connecting the incident surface and the first reflecting surface is the second reflecting surface. 6. The binocular image display device according to 5 above, wherein an optical path connecting the exit surface intersects within the prism.
[0129]
[7] The decentered prism includes three reflecting surfaces, and the third reflecting surface is formed by a surface that also serves as an incident surface on which light from the image display element or the aerial image is incident. 6. The binocular image display device according to 5 above, wherein the reflecting surface is formed as a surface also serving as an exit surface.
[0130]
[8] The binocular image display according to 5, wherein the decentered prism includes two reflecting surfaces, and includes an incident surface, a first reflecting surface that also serves as an exit surface, and a second reflecting surface. apparatus.
[0131]
[9] The binocular image display as described in 5 above, wherein the decentered prism includes two reflecting surfaces, and includes a second reflecting surface that also serves as an incident surface, a first reflecting surface, and an exit surface. apparatus.
[0132]
[10] The decentered prism is formed of a free-form surface having only one symmetry plane, and each plane constituting the prism other than the discontinuous plane has a symmetry plane in substantially the same plane. 10. The binocular image display device according to any one of 5 to 9 above.
[0133]
[11] The binocular image display device according to any one of 1 to 10, wherein the eyepiece optical system has at least one rotationally asymmetric surface.
[0134]
[12] The binocular image display device according to any one of 1 to 11, wherein the eyepiece optical system is a reflection optical system.
[0135]
[13] The binocular image display device as described in 12 above, wherein the eyepiece optical system has a Fresnel reflecting surface.
[0136]
[14] The binocular image display device according to any one of [1] to [11], wherein the eyepiece optical system is a refractive optical system.
[0137]
[15] The binocular image display device as described in 14 above, wherein the eyepiece optical system has a Fresnel transmission surface.
[0138]
[16] The binocular image display device according to any one of [1] to [11], wherein the eyepiece optical system is a diffractive optical system.
[0139]
[17] A relay optical system that projects an image displayed on the image display element or an aerial image formed by another optical system as an object point, and a light beam from the relay optical system directed toward an observer's eye In an image display device having an eyepiece optical system having a convergence action that converges in
The image display element comprises a pair of image display elements, and the aerial image comprises a pair of aerial images formed in parallel,
The relay optical system uses a pair of images displayed on the image display element or the pair of aerial images arranged in parallel as object points, and guides light beams emitted from these object points to separate optical paths, and on the two optical paths. Consists of an optical system that forms left and right exit pupils,
The eyepiece optical system guides the two optical paths that have passed through the relay optical system to the left and right exit pupils corresponding to the observer's eyes, and the left and right exit pupils formed by the relay optical system correspond to the observer's eyes Have at least positive power to project to the left and right exit pupil positions,
The optical axes of the two optical paths guided from the eyepiece optical system to the left and right exit pupils corresponding to the observer's eyes are arranged so as to intersect on the observer's eyes side with respect to the eyepiece optical system. A binocular image display device.
[0140]
[18] The relay optical system is configured to form an image displayed on the pair of image display elements or a pair of aerial images formed in parallel in the vicinity of the eyepiece optical system. 18. The binocular image display device as described in 17 above.
[0141]
[19] The binocular image display device as described in 18 above, wherein an optical surface having directional diffusivity is disposed in the vicinity of the eyepiece optical system.
[0142]
[20] The shape of each of the left and right exit pupils by the relay optical system is an ellipse that is long to the left and right, and the optical surface having directional diffusibility has a diffusing action only in the vertical direction perpendicular to the long axis of the ellipse. 20. The binocular image display device as described in 19 above, which is an optical surface.
[0143]
[21] The relay optical system includes a pair of decentered prisms formed of a medium having a refractive index (n) larger than 1 (n> 1), and each decentered prism includes a corresponding image display element or aerial image. And at least one reflecting surface for reflecting the light beam in the prism, and an exit surface for emitting the light beam outside the prism, and at least one reflecting surface. 21. The binocular image display device as described in any one of 17 to 20 above, which comprises a rotationally asymmetric surface that gives power to the luminous flux.
[0144]
[22] The decentered prism includes two reflecting surfaces, and includes an incident surface, a first reflecting surface, a second reflecting surface, and an exit surface, and an optical path connecting the incident surface and the first reflecting surface is the second reflecting surface. 22. The binocular image display device as described in 21 above, wherein an optical path connecting the exit surface intersects in the prism.
[0145]
[23] The decentered prism includes three reflecting surfaces, and the third reflecting surface is formed of a surface that also serves as an incident surface on which light from a corresponding image display element or aerial image is incident. 22. The binocular image display device as described in 21 above, wherein the reflecting surface is formed as a surface also serving as an exit surface.
[0146]
[24] The binocular image display according to item 21, wherein the decentered prism includes two reflecting surfaces, and includes an incident surface, a first reflecting surface that also serves as an exit surface, and a second reflecting surface. apparatus.
[0147]
[25] The binocular image display as described in 21 above, wherein the decentered prism comprises two reflecting surfaces, and comprises a second reflecting surface that also serves as an incident surface, a first reflecting surface, and an exit surface. apparatus.
[0148]
[26] The decentered prism is formed of a free-form surface having only one plane of symmetry, and each plane constituting the prism other than the discontinuous plane has a plane of symmetry substantially in the same plane. 26. The binocular image display device according to any one of 21 to 25 above.
[0149]
[27] The binocular image display device according to any one of 21 to 26, wherein the eyepiece optical system has at least one rotationally asymmetric surface.
[0150]
[28] The binocular image display device according to any one of 21 to 27, wherein the eyepiece optical system is a reflection optical system.
[0151]
[29] The binocular image display device as described in 28 above, wherein the eyepiece optical system has a Fresnel reflecting surface.
[0152]
[30] The binocular image display device according to any one of 21 to 27, wherein the eyepiece optical system is a refractive optical system.
[0153]
[31] The binocular image display device as described in 30 above, wherein the eyepiece optical system has a Fresnel transmission surface.
[0154]
[32] The binocular image display device according to any one of 21 to 27, wherein the eyepiece optical system comprises a diffractive optical system.
[0155]
【The invention's effect】
As is clear from the above description, the present invention can provide a binocular image display device that can be observed as a stereoscopic image or the like with both eyes, is small, and has a small number of components.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a basic form of a binocular image display device of the present invention.
FIG. 2 is a schematic perspective view showing a configuration of a binocular image display device when a relay optical system is configured by a single decentered prism.
FIG. 3 is a schematic perspective view illustrating a configuration of a binocular image display device in a case where a relay optical system includes a pair of decentered prisms.
FIG. 4 is a schematic perspective view showing a configuration of a single decentered prism constituting the relay optical system.
FIG. 5 is a diagram showing an exit pupil formed in a long ellipse on the left and right.
FIG. 6 is a diagram for explaining the diffusibility of a diffusive optical surface arranged in an eyepiece optical system.
FIG. 7 is a schematic perspective view showing a binocular image display device of the present invention configured in a handheld viewer type configuration.
FIG. 8 is an optical path diagram of one optical system projected onto a YZ plane according to the first embodiment of the present invention.
9 is an optical path diagram of one optical system projected onto the XZ plane of Example 1. FIG.
10 is an optical path diagram of only chief rays projected onto the XZ plane of the optical system on both sides of Example 1. FIG.
11 is an enlarged view of the vicinity of a decentered prism of the image display element and relay optical system of FIG. 10;
12 is an optical path diagram of only the principal ray of one optical system projected onto the YZ plane of Embodiment 2. FIG.
13 is an optical path diagram of only the principal ray of one optical system projected onto the XZ plane of Embodiment 2. FIG.
14 is an optical path diagram of only chief rays projected onto the XZ plane of the optical system on both sides of Example 2. FIG.
15 is an optical path diagram of only the principal ray of one optical system projected onto the YZ plane of Embodiment 3. FIG.
16 is an optical path diagram of only the principal ray of one optical system projected onto the XZ plane of Example 3. FIG.
17 is an optical path diagram of only chief rays projected onto the XZ plane of the optical system on both sides of Example 3. FIG.
18 is an enlarged view of the vicinity of the decentered prism of the image display element and relay optical system of FIG. 17;
19 is a diagram showing lateral aberration of the optical system on one side of Example 1. FIG.
FIG. 20 is an optical path diagram showing an example of a binocular entity observation device according to the present invention.
FIG. 21 is a diagram showing several examples of decentered prisms that can be used in the relay optical system of the binocular image display device of the present invention.
[Explanation of symbols]
1L, 1R ... exit pupil
2L, 2R ... Optical axis
3, 3L, 3R ... Image display element
3 '... Image plane
10, 10L, 10R ... Eccentric prism
11 ... first side
12 ... the second side
13 ... Third surface
14 ... Fourth side
14L, 14R: Optical surfaces constituting discontinuous surfaces
20 ... Fresnel reflector
21 ... Transmission surface on the exit pupil side of the eyepiece optical system
22 ... Fresnel reflecting surface on the opposite side of the eyepiece optical system
30 ... Display device body
31 ... Relay optical system
32 ... Eyepiece optical system
33 ... Reflecting surface (plane mirror)
34 ... Operation buttons
35 ... Objective lens
36L, 36R ... Pupil
P: Intersection of left and right optical axes
O ... Solid objects

Claims (4)

A relay optical system that projects an image displayed on an image display element or an aerial image formed by another optical system as an object point, and a light beam from the relay optical system converges toward an observer's eye In an image display apparatus having an eyepiece optical system having a convergence action,
The relay optical system includes a prism member , divides a light beam emitted from an object displayed on the image display element or the aerial image as an object point into two optical paths, and on the two optical paths. Forming left and right exit pupils ,
At least one optical action surface of the prism member is composed of a discontinuous surface composed of two adjacent surfaces,
At least one optical working surface of the prism member is composed of a rotationally asymmetric surface that corrects aberrations caused by decentration,
The eyepiece optical system guides the two optical paths divided by the relay optical system to the left and right exit pupils corresponding to the observer's eyes, and the left and right exit pupils formed by the relay optical system to the observer's eyes Having at least positive power to project to the left and right exit pupil positions corresponding to
The optical axes of the two optical paths guided from the eyepiece optical system to the left and right exit pupils corresponding to the observer's eyes are arranged so as to intersect on the observer's eyes side with respect to the eyepiece optical system. A binocular image display device.   The relay optical system is configured to form an image displayed on the image display element or an aerial image formed by another optical system in the vicinity of the eyepiece optical system. The binocular image display device according to claim 1.   3. The binocular image display device according to claim 2, wherein an optical surface having directional diffusivity is disposed in the vicinity of the eyepiece optical system.   The shape of each of the left and right exit pupils by the relay optical system is an ellipse that is long to the left and right, and the directional diffusive optical surface has a diffusing action in the vertical direction perpendicular to the long axis of the ellipse, 4. The binocular image display device according to claim 3, wherein is an optical surface having almost no diffusing action.

Images