JP3597456B2 - Eccentric optical system and visual display device using the same - Google Patents

Description

ここで、Ｋ_ｘ はＸ方向の円錐係数、Ｋ_ｙ はＹ方向の円錐係数、ＡＲ、ＢＲはそれぞれ回転対称な４次、６次の非球面係数、ＡＰ、ＢＰはそれぞれ非対称な４次、６次の非球面係数である。
【００５９】
また、面間隔は、射出瞳２と凹面鏡３の間については、射出瞳２中心と凹面鏡３頂点間のＺ軸方向の間隔、リレー光学系１５の第１面からその像面（２次元画像表示素子１４）に到る間隔は、その光軸に沿う間隔で示してある。リレー光学系１５については、面の曲率半径をｒ_１ 〜ｒ_ｉ で、面間隔をｄ_１ 〜ｄ_ｉ で、ｄ線の屈折率をｎ_１ 〜ｎ_ｉ で、アッベ数をν_１ 〜ν_ｉ で示す。

上記実施例の画角は、左右画角が４５°、上下画角が３４．６５°で、瞳径８ｍｍである。
【００６０】
この実施例の収差補正状態を示すスポットダイアグムを図１３に示す。図１３において、スポットダイアグムの左側の４つの数字の中、上段の２つの数字は、長方形の画面中央の座標（Ｘ，Ｙ）を（０．００，０．００）、右端中央の座標を（０．００，−１．００）、右上隅の座標を（１．００，−１．００）、上端中央の座標を（１．００，０．００）のように表現した場合の座標（Ｘ，Ｙ）を示し、下段の２つの数字は、視軸（画面中央）に対して上記座標（Ｘ，Ｙ）方向がなす角度のＸ成分、Ｙ成分（度表示）を示す。
実施例２
図６を参照にして、実施例２について説明する。この実施例の構成は実施例１と同じであるが、接眼凹面鏡３がＹ軸を軸とする回転楕円鏡からなる。
【００６１】
以下、この光学系の構成パラメータを示すが、面番号は、射出瞳２位置から２次元画像表示素子１４へ向かう逆追跡の面番号として示してある。座標系のとり方、偏心量、傾き角の与え方、各面の曲率半径、面間隔、屈折率、アッベ数も実施例１と同様である。各面の非球面形状も同様であるが、接眼凹面鏡３については、曲率半径をＲとすると、次の式で表される。
【００６２】
Ｚ＝（ｈ^２／Ｒ）／［１＋｛ １−（１＋Ｋ） （ ｈ^２／Ｒ^２）｝^１／２ ］＋Ａｈ^４ ＋Ｂｈ^６
（ｈ^２ ＝Ｘ^２ ＋Ｙ^２ ）
ここで、Ｋは円錐係数、Ａ、Ｂはそれぞれ４次、６次の非球面係数である。

上記実施例の画角は、左右画角が４５°、上下画角が３４．６５°で、瞳径８ｍｍである。
【００６３】
この実施例の収差補正状態を示す図１３と同様なスポットダイアグムを図１４に示す。
実施例３
図７を参照にして、実施例３について説明する。この実施例の構成は実施例１と同じである。
【００６４】
以下、この光学系の構成パラメータを示すが、面番号は、射出瞳２位置から２次元画像表示素子１４へ向かう逆追跡の面番号として示してある。座標系のとり方、偏心量、傾き角の与え方、各面の曲率半径、面間隔、屈折率、アッベ数、非球面形状も実施例１と同様である。

上記実施例の画角は、左右画角が４５°、上下画角が３４．６５°で、瞳径６ｍｍである。
【００６５】
この実施例の収差補正状態を示す図１３と同様なスポットダイアグムを図１５に示す。
実施例４
図８を参照にして、実施例４について説明する。この実施例の構成は実施例１とほぼ同じである。
【００６６】
以下、この光学系の構成パラメータを示すが、面番号は、射出瞳２位置から２次元画像表示素子１４へ向かう逆追跡の面番号として示してある。座標系のとり方、偏心量、傾き角の与え方、各面の曲率半径、面間隔、屈折率、アッベ数、非球面形状も実施例１と同様である。

上記実施例の画角は、左右画角が５０°、上下画角が３５°で、瞳径８ｍｍである。なお、上記の表中、面番号：５の偏心量、傾き角の括弧内の数値にリレーレンズ系１５を移動することによって、左右の観察画角が５０°から３０°に切り換え可能となっている。
【００６７】
この実施例の広い画角時及び狭い画角時の収差補正状態を示す図１３と同様なスポットダイアグムをそれぞれ図１６、図１７に示す。
実施例５
図９を参照にして、実施例５について説明する。この実施例の構成は実施例１とほぼ同じである。
【００６８】
以下、この光学系の構成パラメータを示すが、面番号は、射出瞳２位置から２次元画像表示素子１４へ向かう逆追跡の面番号として示してある。座標系のとり方、偏心量、傾き角の与え方、各面の曲率半径、面間隔、屈折率、アッベ数、非球面形状も実施例１と同様である。
【００６９】
なお、以下に示す実施例５〜８の何れも接眼凹面鏡３による屈曲角は７０°である。

上記実施例の画角は、左右画角が５０°、上下画角が３８．５°で、瞳径１０ｍｍである。
【００７０】
この実施例の収差補正状態を示す図１３と同様なスポットダイアグムを図１８〜図２０に示す。
実施例６
図１０を参照にして、実施例６について説明する。この実施例の構成は実施例１とほぼ同じである。
【００７１】
以下、この光学系の構成パラメータを示すが、面番号は、射出瞳２位置から２次元画像表示素子１４へ向かう逆追跡の面番号として示してある。座標系のとり方、偏心量、傾き角の与え方、各面の曲率半径、面間隔、屈折率、アッベ数も実施例１と同様である。各面の非球面形状も同様であるが、リレー光学系１５については、実施例２の式で表される。

上記実施例の画角は、左右画角が５０°、上下画角が３８．５°で、瞳径１０ｍｍである。
実施例７
図１１を参照にして、実施例７について説明する。この実施例の構成は実施例６とほぼ同じである。
【００７２】
以下、この光学系の構成パラメータを示すが、面番号は、射出瞳２位置から２次元画像表示素子１４へ向かう逆追跡の面番号として示してある。座標系のとり方、偏心量、傾き角の与え方、各面の曲率半径、面間隔、屈折率、アッベ数、非球面形状も実施例６と同様である。

上記実施例の画角は、左右画角が５０°、上下画角が３８．５°で、瞳径１０ｍｍである。
実施例８
図１２を参照にして、実施例８について説明する。この実施例の構成は実施例６とほぼ同じである。
【００７３】
以下、この光学系の構成パラメータを示すが、面番号は、射出瞳２位置から２次元画像表示素子１４へ向かう逆追跡の面番号として示してある。座標系のとり方、偏心量、傾き角の与え方、各面の曲率半径、面間隔、屈折率、アッベ数、非球面形状も実施例６と同様である。

上記実施例の画角は、左右画角が５０°、上下画角が３５°で、瞳径１０ｍｍである。
【００７４】
実施例５〜８の場合、リレー光学系１５を観察者頭部（眼球上部）に配置することが可能となり、偏心補正光学系８が眼球の上部に位置するため、空中像ではなく外界像を観察している時に、偏心補正光学系８が邪魔をして外界の観察像の視野が観察できなくなる問題が発生しない。この問題が起こると、視覚表示装置を装着したまま他の仕事をしたり、場所を移動したりする時に、観察者の視野の狭さからくる不安を与えることになってしまう。
【００７５】
【発明の効果】
以上の説明から明らかなように、本発明に基づき、広い提示画角で、周辺の画角まで鮮明に観察できる頭部装着式視覚表示装置用偏心光学系を提供することができる。
【００７６】
また、眼鏡等を装着したまま空間に投影された広い観察画角の空中像を鮮明に観察することが可能な頭部装着式視覚表示装置偏心光学系を提供することができる。
【図面の簡単な説明】
【図１】本発明の視覚表示装置の概念図である。
【図２】本発明による偏心補正光学系の光路図である。
【図３】視覚表示装置の接眼凹面鏡によって発生する像面湾曲を示す図である。
【図４】眼の回旋運動によって視野がケラレる様子を示す図である。
【図５】本発明の実施例１の光学的構成を示す断面図である。
【図６】実施例２の光学的構成を示す断面図である。
【図７】実施例３の光学的構成を示す断面図である。
【図８】実施例４の光学的構成を示す断面図である。
【図９】実施例５の光学的構成を示す断面図である。
【図１０】実施例６の光学的構成を示す断面図である。
【図１１】実施例７の光学的構成を示す断面図である。
【図１２】実施例８の光学的構成を示す断面図である。
【図１３】実施例１の収差補正状態を示すスポットダイアグムである。
【図１４】実施例２の収差補正状態を示すスポットダイアグムである。
【図１５】実施例３の収差補正状態を示すスポットダイアグムである。
【図１６】実施例４の広い画角時の収差補正状態を示すスポットダイアグムである。
【図１７】実施例４の狭い画角時の収差補正状態を示すスポットダイアグムである。
【図１８】実施例５の収差補正状態を示すスポットダイアグムの一部である。
【図１９】実施例５の収差補正状態を示すスポットダイアグムの別の一部である。
【図２０】実施例５の収差補正状態を示すスポットダイアグムの残りの部分である。
【図２１】従来の頭部装着式視覚表示装置の構成を示す平面図である。
【図２２】本出願人による先行技術の頭部装着式視覚表示装置の構成を示す断面図である。
【符号の説明】
１…観察者眼球
２…観察者瞳位置
３…接眼凹面鏡
４…観察者の視軸
５…接眼凹面鏡による無限遠物体の像面
６…接眼凹面鏡によって屈曲した光軸
７…観察者の瞳投影位置
８…偏心補正光学系
９…偏心補正光学系を射出した後の光軸
１４…２次元画像表示素子
１５…リレー光学系
１８…偏心補正光学系で補正された像面[0001]
[Industrial applications]
The present invention relates to an eccentric optical system and a visual display device using the same, and more particularly, to an eccentric optical system used for a head or face-mounted visual display device capable of being held on the head or face of an observer. The present invention relates to the visual display device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a head-mounted visual display device, a device as shown in a plan view in FIG. 21 is known (US Pat. No. 4,266,641). This is such that an image of an image display element 46 such as a CRT is transmitted to the object plane 12 by the image transmission element 25, and the image of the object plane 12 is projected into the air by the toric reflection surface 10.
[0003]
Further, as a prior art by the present applicant, Japanese Patent Application No. 3-295874 discloses a head mounted visual display device using an eccentrically arranged concave eyepiece optical system and an eccentrically arranged relay optical system. FIG. 22 shows a cross-sectional view of the first embodiment. In the figure, P is the center of rotation of the observer's eyeball 13, C is the observation visual axis corresponding to the front of the observer, Q₁Is the observer pupil position, S₈Is a spheroid with T as the center of rotation, 16 is the reflection surface of the spheroid, 17 is the optical axis of the relay optical system, Q₂Is a focal point of a spheroid, 15 is a relay optical system, and 14 is a two-dimensional image display element.
[0004]
[Problems to be solved by the invention]
For a head-mounted visual display device, reducing the size of the entire device and reducing its weight are important points in order not to impair the wearability. The factor that determines the size of the entire device is the layout of the optical system.
[0005]
In order to reduce the size of the entire apparatus, in a direct-view layout in which the two-dimensional image display element is directly observed by enlarging the two-dimensional image display element with a convex lens, the amount of projection of the apparatus from the observer's face becomes large. Further, in order to obtain a wide viewing angle of view, it is necessary to use a large positive lens system and a large two-dimensional image display element.
[0006]
In order to enable long-term observation without causing fatigue and to easily attach and detach the eyepiece, it is desirable to employ a configuration in which an eyepiece optical system including a reflective surface is arranged immediately before the observer's eyeball. Thus, the two-dimensional image display element and the illumination optical system can be arranged in a small area around the observer's head, so that the projection amount of the device is reduced and the weight can be reduced.
[0007]
Next, it is necessary to secure a large angle of view in order to increase the sense of reality during image observation. In particular, the stereoscopic effect of the presented image is determined by the angle of view (Television Society Journal, Vol. 45, No. 12, pp. 1589-1596 (1991)).
[0008]
The next important issue is how to realize an optical system that can obtain a wide angle of view and high resolution.
[0009]
In order to give the observer a three-dimensional feeling, a powerful feeling, and the like, it is necessary to secure a presentation angle of view of 40 ° (± 20 °) or more in the horizontal direction, and at the same time, in the vicinity of 120 ° (± 60 °) It is known that the effect is saturated. That is, it is desirable to set the observation angle of view to 40 ° or more and as close as possible to 120 °. However, when the eyepiece optical system is a flat reflecting mirror, if an attempt is made to make the above-described light ray having an angle of view of 40 ° or more into the eyeball of the observer, a very large two-dimensional image display element is required. Required, and eventually the whole device becomes large and heavy.
[0010]
Further, due to the nature of the concave mirror, in order to generate strong image field distortion of the concave surface along the surface of the concave mirror, if a planar two-dimensional image display element is arranged at the focal position of the concave mirror, the observation image plane will be curved. And a clear observation image cannot be obtained up to the periphery of the visual field. A method of arranging the display surface of a two-dimensional image display element in a curved manner also exists as in the prior art shown in FIG. However, even if the two-dimensional image display element is arranged at the front focal position of the concave mirror using a concave mirror as shown in FIG. When providing an observation angle of view, it was difficult to obtain a high resolving power due to the aberration of the concave mirror.
[0011]
Further, when a correction optical system having an eccentric arrangement as shown in FIG. 22 is used, since the eccentricity correction optical system is located near the face, an image cannot be observed using eyeglasses or the like. This is because, as is apparent from FIG. 22, the edge of the spectacles interferes with the eccentricity correction optical system, and the light from the relay optical system that forms the observation image impinges on the spectacle lens from the back side. This is because the observation image cannot be observed.
[0012]
The present invention has been made in view of such problems, and provides a wide viewing angle of view, and is compact and lightweight, and has a high resolution and a large exit pupil diameter. An object of the present invention is to provide a visual display device that can be observed while wearing glasses while being a visual display device.
[0013]
Hereinafter, an object of the present invention for providing a large exit pupil diameter will be described. Unless the diameter of the exit pupil of the optical system is made large, the visual field will be vignetted by the rotational movement of the eye when observing the peripheral angle of view. This is shown in FIG. FIG. 7A shows a case where the pupil position 2 of the eye 1 of the observer observing the center of the visual field matches the exit pupil diameter position of the optical system, and FIG. In this case, the observer tries to rotate the eye 1 in that direction and looks at it. Since the center of rotation of the pupil 2 of the observer and the center of rotation of the eyeball 1 are displaced, in FIG. It will be like. For this reason, for example, when the eyeball 1 is turned to the left in order to observe the left direction, a problem occurs that the right visual field becomes invisible due to vignetting.
[0014]
The pupil of the observer and the exit pupil of the apparatus itself change depending on the state of the apparatus. Unless the device has an exit pupil diameter that has a certain margin with respect to the observer's pupil diameter, it is not possible to absorb the difference between the observer's pupil position and the device's exit pupil position that occurs when the device is attached or due to individual differences between observers. In addition, the observation image is obstructed by the observer's pupil, and a wide observation angle of view cannot be secured.
[0015]
In order to solve this problem, it is important to design the exit pupil diameter of the observation system to be large. Even with a general camera lens, it is difficult to increase the pupil diameter, that is, to reduce the F-number, in correcting the aberration of the lens, and it is very difficult to double the pupil diameter. For example, in the case of a camera standard lens having an F number of 2.8 and a focal length of 50 mm and a standard lens having an F number of 1.4, the number of components needs to be changed from three triplet types to six Gaussian types. As described above, doubling the pupil diameter (F number) greatly changes the configuration of the optical system and causes an increase in the size of the lens configuration.
[0016]
By the way, about half of ordinary people have visual impairments such as myopia and astigmatism. In recent years, contact lenses have become widespread and the proportion of contact lens wearers has increased, but contact lenses are limited to use by some people because of their handling and maintainability, and they have problems with price and handling. Most people use glasses.
[0017]
In order for a person using the glasses to wear a visual display device as shown in, for example, FIGS. It is necessary to provide diopter correction means.
[0018]
However, the provision of diopter correction means including astigmatism in a visual display device such as the present invention for the purpose of small size and light weight causes an increase in the size and weight of the device, and a diopter correction amount on the device side. It can be very difficult to be able to properly adjust to fit the observer. In addition, if an observer who has normal observation visual acuity with an incorrect diopter observes for a long time, the diopter of the observer conversely adjusts to the incorrect diopter on the device side, and the observation is performed. There is also a risk that the eyesight of the elderly will deteriorate.
[0019]
Further, in the so-called “superimposition” observation in which the aerial image of the two-dimensional image display element and the observation image of the external world are superimposed and observed, the diopter of the external image and the aerial image projected into space by the visual display device. In both cases, it is necessary to add a diopter correction mechanism, which further increases the size of the apparatus.
[0020]
The present invention has been made to solve the above problems, and a first object of the present invention is to provide a flat and clear image that can be observed at an observation angle of view of 40 ° (± 20 °) or more. It is an object of the present invention to provide an eccentric optical system for a visual display device, which can observe an image and further secures a wide exit pupil diameter.
[0021]
Another object of the present invention is to provide an eccentric optical system for a visual display device capable of clearly observing an aerial image with a wide observation angle of view projected on a space while wearing glasses or the like. is there.
[0022]
[Means for Solving the Problems]
A first decentered optical system of the present invention that achieves the above object is a decentered optical system that is disposed between an image plane and a pupil of an observer and includes an optical surface decentered with respect to at least an optical axis.
The decentered optical system includes at least a first transmission surface, a second transmission surface, a first reflection surface, and a relay optical system,
The first reflection surface, the first transmission surface and the second transmission surface that are closer to the image surface side than the first reflection surface on the optical path are configured to transmit light from an infinite object point located on the pupil side of the observer. Condensing to form a relay image near the first transmission surface;
The relay optical system projects the relay image on the image plane,
The first reflecting surface is eccentrically arranged with the concave surface facing in the direction in which light rays are reflected, and the shape is not rotationally symmetric, and is configured in an aspherical shape including a rotationally asymmetrical aspherical coefficient,
The first transmission surface and the second transmission surface are arranged in a wedge shape,
In order to correct at least the astigmatic difference that is not rotationally symmetric and is generated by the first reflecting surface, the optical element is configured to have an aspherical shape including a rotationally asymmetrical aspherical coefficient.
[0023]
The second decentered optical system of the present invention is disposed between the image plane and the pupil of the observer, in the decentered optical system including at least an optical surface decentered with respect to the optical axis,
The decentered optical system includes at least a first transmission surface, a second transmission surface, a first reflection surface, and a relay optical system,
The first reflection surface, the first transmission surface and the second transmission surface that are closer to the image surface side than the first reflection surface on the optical path are configured to transmit light from an infinite object point located on the pupil side of the observer. Condensing to form a relay image near the first transmission surface;
The relay optical system projects the relay image on the image plane,
The first reflection surface is eccentrically arranged with the concave surface facing the direction in which light rays are reflected, and the surface shape includes both the optical axis incident on the first reflection surface and the optical axis emitted after reflection. A rotationally asymmetric aspherical shape in which the surface shape when the YZ plane is a cross section and the surface shape when the XZ plane perpendicular to the optical axis is a cross section are different from each other. Composed,
The first transmission surface and the second transmission surface are arranged in a wedge shape,
A surface shape when the YZ plane is cross-sectioned to correct at least astigmatic difference that is not rotationally symmetric generated by the first reflecting surface, and an XZ plane perpendicular to the YZ plane and the optical axis. Are formed in a rotationally asymmetric aspherical shape different from each other in the surface shape when the section is taken as a cross section.
[0024]
In these cases, the decentered optical system has a second transmission surface separately from the first transmission surface, and the second transmission surface is correlated with the first transmission surface and has at least a rotation generated by the first reflection surface. It is desirable to be configured with a rotationally asymmetric aspherical shape that corrects an asymmetry difference that is not symmetric.
[0025]
And the decentering optical system arranges a relay optical group that forms the relay image between the first transmission surface and the image surface,
It is preferable that the relay optical group is configured to relay the planar image surface into a light path as a curved and curved relay image.
[0026]
In addition, it is desirable that the first reflection surface is arranged to be inclined on a straight line of the optical axis that passes through the center of the pupil.
[0027]
Further, it is preferable that the first reflecting surface is configured such that a bending angle when the optical axis is reflected and bent by the reflecting surface is 60 ° or more.
[0028]
The present invention includes a visual display device including an image display device arranged on an image plane and any one of the above-described decentered optical systems.
[0029]
[Action]
Hereinafter, the reason and the operation of the above arrangement will be described. The following description will be made along the optical path of reverse tracing for tracing light rays from the observer's pupil position to the two-dimensional image display element for convenience in design.
[0030]
The eccentricity correction optical element arranged between the eyepiece concave reflecting optical system and the relay optical system is for correcting aberrations that are not symmetric with respect to the optical axis generated by the eyepiece concavely reflecting optical system arranged eccentrically. is there.
[0031]
Hereinafter, the reason for the above arrangement will be described with reference to FIG. 3 in which the relay optical system is omitted. FIG. 3 is a diagram showing the field curvature generated by the eyepiece concave mirror of the optical system corresponding to the right eye of the observer by reverse tracking. This figure shows the optical system for the right eye, and the optical system for the left eye is symmetrically arranged. In this figure, the observer's eyeball is 1, the observer's pupil position is 2, the eyepiece concave mirror is 3, the observer's visual axis is 4, the image plane of an object at infinity by the eyepiece concave mirror 3 is 5, and the light bent by the eyepiece concave mirror 3. The axis is indicated by 6 and the pupil projection position of the observer by the ocular concave mirror 3 is indicated by 7.
[0032]
In this figure, the pupil diameter at the observer's eyeball position 1 is 8 mm, and the angle of view of the tracking ray is 50 ° (half angle of view 25 °) and 35 ° (half angle of view 17.5 °). FIG. As described above, in an eyepiece concave reflection optical system having a wide angle of view exceeding 40 °, the focal plane 5 of the concave mirror is curved as an imaging characteristic of the concave mirror. The visual axis 4, which is the center of the observation angle of view, is reflected by the ocular concave mirror 3 and becomes the optical axis 6. Since the concave mirror 3 is arranged eccentrically with respect to the visual axis 4, the image plane 5 and the optical axis 6 are not perpendicular to each other, but are formed as the image plane 5 inclined obliquely with respect to the optical axis 6.
[0033]
That is, since the optical axis 6 is also bent by the concave mirror 3 which is decentered, the image plane 5 which is inclined and curved with respect to the optical axis 6 which is the center of the observation angle of view is formed. This curvature of field is the same whether the concave reflecting mirror 3 is formed of an aspherical surface or a toric surface.
[0034]
Projecting this image plane on a two-dimensional image display device with a relay optical system requires the relay optical system to project an inclined and curved object surface onto a planar two-dimensional image display device. It is generally known that the eccentricity of the relay lens system and the inclination of the two-dimensional image display element can correct the inclination and curvature of the image plane without the eccentricity correction optical system as in the present invention. It is difficult to simultaneously satisfy a large pupil diameter and high resolving power as in the present invention, and a large-scale relay optical system is required.
[0035]
Therefore, in the present invention, an eccentricity correction optical system that raises an object surface that is inclined and curved with respect to the optical axis perpendicular to the optical axis and corrects the field curvature is provided by an ocular concave reflecting optical system and a relay optical system. By arranging them near the image plane, the inclination and the curvature of the image plane with respect to the optical axis as described above have been successfully corrected at the same time.
[0036]
At least one surface of the eccentricity correction optical system is inclined not only with respect to the optical axis but also with respect to the optical axis of the relay optical system, and at the same time, the two surfaces of the eccentricity correction optical system are mutually inclined. It is preferable to configure with an eccentric surface. This is because the image plane formed by the eyepiece concave mirror is not simply a plane that is inclined but a curved surface having a curvature and is also inclined. In order to correct the inclined image plane to a plane, it is necessary to compose the eccentricity correction optical system with a complicatedly decentered curved surface.
[0037]
The effect of such a configuration will be described with reference to the conceptual diagram of the present invention in FIG. 1, the observer's eyeball position is 1, the observer's iris position is 2, the eyepiece concave mirror is 3, the observer's visual axis is 4, the image plane of an object at infinity by the eyepiece concave mirror 3 is 5, and the eyepiece concave mirror 3 is used. The reflected visual axis is denoted by 6, the eccentricity correcting optical system is denoted by 8, the optical axis after the eccentricity correcting optical system 8 is emitted is denoted by 9, and the image plane corrected by the eccentricity correcting optical system is denoted by 18.
[0038]
First, it is important that the eccentricity correction optical system 8 is wedge-shaped. As shown in FIG. 1, the wedge-shaped eccentricity correction optical system 8 has an optical path length that is asymmetrical with respect to the visual axis 6, so that the image 5 formed to be inclined with respect to the visual axis 6 is To convert the image plane 18 into a substantially vertical image plane 18.
[0039]
Next, an eccentricity correction optical system 8 is provided for correcting a field curvature symmetrical with respect to the visual axis, and for correcting a field curvature having a concave surface with respect to the relay optical system (omitted in FIG. 1). First surface S of₁To S in FIG.₂With the convex surface as described above, the field curvature can be corrected. As a result, the relay optical system only needs to project a flat image plane onto the two-dimensional image display element, so that the burden of aberration correction on the relay optical system has been greatly reduced, and the relay optical system has been successfully constructed with a small relay optical system. Things.
[0040]
FIG. 2 shows an optical path diagram of the eccentricity correcting optical system according to the present invention. This figure shows the correction state by the eccentricity correction optical system of Example 1 described later. In the figure, the observer's eyeball is 1, the observer's pupil position is 2, the eyepiece concave mirror is 3, and the observer's visual axis is 4, The image plane by the eyepiece concave mirror 3 is 5, the eccentricity correction optical system disposed between the eyepiece concave mirror 3 and the relay optical system (not shown) is 8, the optical axis bent by the eyepiece concave mirror 3 and the eccentricity correction optical system 9 is 9, the eyepiece concave mirror The projection position of the observer's pupil 2 by 3 and the eccentricity correction optical system 8 is indicated by 7, and the image plane corrected by the ocular concave mirror 3 and the eccentricity correction optical system 8 is indicated by 18. As is apparent from this optical path diagram, the image plane 5 formed by the ocular concave mirror 3 is corrected by the eccentricity correction optical system 8 into a flat image plane 18 perpendicular to the optical axis 9.
[0041]
In this way, the eccentricity correction optical system 8 composed of eccentric surfaces reduces the burden of aberration correction in the relay optical system, and satisfies high resolution while securing a large pupil diameter as in the present invention. An observation optical system can be provided. As described above, the first surface and the second surface of the eccentricity correction optical system 8 are wedge-shaped with respect to the on-axis light beam, thereby correcting the inclination of the image plane and forming an observation image with high resolution. Important to provide.
[0042]
More preferably, astigmatism generated by the ocular concave mirror 3 causes a complicated astigmatic difference that is not rotationally symmetric with respect to the visual axis because the ocular concave mirror 3 is eccentrically arranged. In order to correct this complicated astigmatic difference, the eccentricity correcting optical system 8 is desirably constituted by an anamorphic surface, and the refractive power in the YZ axis plane in FIG. A configuration in which the refractive power in the Z-axis plane is reduced is necessary in order to correct astigmatism and provide an observation image with high resolution to the periphery of the visual field.
[0043]
More preferably, the surface of the eccentricity correction optical system 8 on the side of the ocular concave mirror 3 is formed as a convex surface for aberration correction. This means that one surface of the eccentricity correction optical system 8 matches the shape of the curvature of the image plane 5. As a result, the optical path length of the light beam passing through the eccentricity correction optical system 8 becomes shorter at the peripheral angle of view than near the optical axis, which is advantageous for correcting the field curvature. This is important when the role of the eccentricity correction optical system 8 is relatively strong in correcting the field curvature.
[0044]
More preferably, by combining both the eccentricity correcting optical system, the relay optical system, and the eccentricity of the image plane, it is needless to say that more excellent aberration correction can be performed.
[0045]
Further, more preferably, by making the eccentricity correcting optical system or the ocular concave mirror an aspherical surface, it becomes possible to correct pupil aberration incident on the relay optical system as in the eccentricity correcting optical system 8 of FIG. The burden of aberration correction on the optical system is reduced, and the size of the relay optical system can be reduced.
[0046]
More preferably, by arranging a part or all of the relay optical system at an angle to the optical axis 6 (FIG. 1), the chromatic aberration generated in the eccentricity correcting optical system 8 is also corrected by the relay optical system. It is possible to do.
[0047]
More preferably, if the two-dimensional image display device is arranged at an angle so as to reduce the burden of correcting the inclination of the image plane of the eccentricity correcting optical system and obtain a good result for the chromatic aberration correction, a good result is obtained for the overall performance.
[0048]
Further, when the position of the pupil 2 of the observer is located at a position farther from the concave mirror 3 than the front focal position of the ocular concave reflecting optical system 3, the image plane 5 of the ocular concave mirror 3 can be reduced, and the observer's head and Interference with the eccentricity correcting optical element 8 is easily avoided, and the focal length of the ocular concave optical system 3 is set to F_RWhen the distance between the eyepiece concave optical system 3 and the observer iris position 2 is D,
D> 0.5 × F_R                                  ... (1)
It is preferable to satisfy the following conditional expression (1).
[0049]
If the lower limit of the conditional expression (1) is exceeded, the light beam reflected by the ocular concave mirror 3 will be extremely widened, and the eccentricity correction optical system 8 will become large and hit the observer's head. Further, the relay optical system becomes large, and the whole device becomes large.
[0050]
Further, if the distance between the concave eyepiece reflective optical system 3 and the iris position 2 or the rotation point of the eyeball of the observer's eyeball 1 is too short because the eyepiece concave reflective optical system 3 is arranged immediately before the observer's eyeball 1, It may hit your eyelashes or give you a sense of fear. For this reason, it is desirable that the distance D between the eyepiece concave reflection optical system 3 and the observer iris position 2 or the eyeball rotation point be arranged at a distance of 30 mm or more,
D> 30 [mm] (2)
It is preferable to satisfy the following condition (2).
[0051]
Further, when the bending angle of the visual axis is inclined by 60 ° or more as in the second aspect of the present invention, the tilt of the image plane generated by the ocular concave reflecting mirror with respect to the visual axis after bending, and the concave reflecting mirror are inclined obliquely. Due to the occurrence of complicated astigmatism caused by the incidence of the light beam, a clear observation image cannot be observed up to the periphery of the observation field angle. In order to correct the above-mentioned aberration, the radius of curvature of the first surface and the second surface of the eccentricity correction optical system in the YZ-axis plane (plane including the left-right direction and the visual axis of the observer) is set to R._Y1, R_Y2When
R_Y1/ R_Y2<0.5 ... (3)
It is important to satisfy the following condition (3).
[0052]
This condition (3) represents the refractive power of the eccentricity correcting optical system in the YZ plane. However, in the case of the present invention, since the first surface and the second surface of the eccentricity correcting optical system are eccentric to each other, it is impossible to strictly define the refractive power. In the case of the optical system as in the present invention, if the upper limit of 0.5 of the conditional expression (3) is exceeded, especially when a bending angle of 60 ° or more is obtained by the ocular concave mirror, a strong image plane generated by the ocular concave optical system is obtained. It becomes difficult to correct the curvature. This curvature of field is generated by a concave mirror. When the bending angle is relatively small, the image plane is perpendicular to the visual axis after bending and has a gentle curvature. However, when the bending angle exceeds 60 °, both the inclination with respect to the visual axis and the curvature increase, and the strong curvature of field and the inclination of the image plane exceed the limit that can be corrected by the relay optical system. Further, if the eccentricity correction optical system is out of the range represented by the conditional expression (3), the curvature cannot be corrected, and a flat and clear observation image cannot be obtained.
[0053]
【Example】
Hereinafter, Examples 1 to 8 of the visual display device of the present invention will be described.
Example 1
This embodiment will be described with reference to FIG. In the figure, 2 is an observer pupil position, 4 is a visual axis when the observer is observing the front, 3 is an eyepiece concave mirror, 8 is an eccentricity correcting optical system, 15 is a relay optical system, and 14 is a two-dimensional image display. Element.
[0054]
As shown in the figure, the coordinate system is as follows: a Y axis having a positive direction from right to left in the right and left direction of the observer, a Z axis having a positive direction from the eyeball side of the observer's visual axis 4 to the concave mirror 3 side, and a vertical direction. It is defined as the X-axis with the downward direction from top to bottom.
[0055]
Hereinafter, the configuration parameters of this optical system will be described. The surface number is shown as a surface number of reverse tracking from the position of the exit pupil 2 to the two-dimensional image display element 14.
[0056]
For the amount of eccentricity and the inclination angle, only the amount of eccentricity in the Y-axis direction is given for the concave mirror 3 (surface number: 2), and the vertex of the concave mirror 3 is the Y-axis from the visual axis 4 (Z-axis direction) passing through the center of the exit pupil 2. In the eccentricity correction optical system 8, the amount of eccentricity in the positive Y-axis direction and the positive Z-axis direction from the center of the exit pupil 2 at the vertex of each surface (surface numbers: 3 and 4) , The inclination angle of the central axis passing through the vertex of the surface from the Z-axis direction is given. The tilt angle of the center axis of the surface is given by the rotation angle (counterclockwise in the figure) from the positive Z-axis direction to the positive Y-axis direction as the positive direction angle. Regarding the relay optical system 15, the vertex position of the first surface (surface number: 5) is given in the same manner as each surface of the eccentricity correcting optical system 8, and the central axis passing through the vertex becomes the optical axis, and the optical axis Is similarly given. The amount of eccentricity and the inclination angle of the specific surface (surface number: 8) other than the first surface in the relay optical system 15 are perpendicular to the optical axis of the surface before the central axis (optical axis) passing through the vertex of the surface. It is given by the amount of eccentricity and the angle of inclination in various directions. A surface without the display of the amount of eccentricity and the inclination angle indicates that it is coaxial with the surface before it. Further, for the two-dimensional image display element 14 (surface number: 13), the amount of eccentricity in the positive Y-axis direction and the positive Z-axis direction from the center of the exit pupil 2 at the center, and the Z-axis direction of the normal to the surface And the angle of inclination from.
[0057]
The aspherical shape of each surface is represented by a coordinate system as shown in the figure, and the paraxial radius of curvature of each surface is represented by R in the plane perpendicular to the YZ plane (paper surface)._x, The radius of curvature in the YZ plane is R_yThen, it is expressed by the following equation.
[0058]

Where K_xIs the cone coefficient in the X direction, K_yIs a conic coefficient in the Y direction, AR and BR are rotationally symmetric fourth and sixth order aspherical coefficients, and AP and BP are asymmetrical fourth and sixth order aspherical coefficients, respectively.
[0059]
In addition, the surface distance between the exit pupil 2 and the concave mirror 3 is the distance between the center of the exit pupil 2 and the vertex of the concave mirror 3 in the Z-axis direction, the first surface of the relay optical system 15 and its image plane (two-dimensional image display). The distance to the element 14) is indicated by the distance along the optical axis. For the relay optical system 15, the radius of curvature of the surface is represented by r₁~ R_iAnd the surface spacing is d₁~ D_iAnd the refractive index of the d-line is n₁~ N_iAnd the Abbe number is ν₁~ Ν_iIndicated by

The angle of view in the above embodiment is such that the left and right angles of view are 45 °, the upper and lower angles of view are 34.65 °, and the pupil diameter is 8 mm.
[0060]
FIG. 13 shows a spot diagram showing the aberration correction state of this embodiment. In FIG. 13, among the four numbers on the left side of the spot diagram, the two numbers in the upper row indicate coordinates (X, Y) at the center of the rectangular screen (0.00, 0.00) and coordinates at the center on the right end. (0.00, -1.00), the coordinates at the upper right corner are expressed as (1.00, -1.00), and the coordinates at the upper center are expressed as (1.00, 0.00). X, Y), and the lower two numbers indicate the X component and the Y component (in degrees) of the angle formed by the coordinates (X, Y) direction with respect to the visual axis (center of the screen).
Example 2
Embodiment 2 will be described with reference to FIG. The configuration of this embodiment is the same as that of the first embodiment, except that the ocular concave mirror 3 is a spheroidal mirror having the Y axis as an axis.
[0061]
Hereinafter, the configuration parameters of this optical system will be described. The surface number is shown as a surface number of reverse tracking from the position of the exit pupil 2 to the two-dimensional image display element 14. The method of setting the coordinate system, the amount of eccentricity, the method of giving the inclination angle, the radius of curvature of each surface, the surface interval, the refractive index, and the Abbe number are the same as those in the first embodiment. The same applies to the aspherical shape of each surface. However, with respect to the eyepiece concave mirror 3, if the radius of curvature is R, it is expressed by the following equation.
[0062]
Z = (h²/ R) / [1+ ｛1- (1 + K) (h²/ R²)｝^1/2] + Ah⁴+ Bh⁶
(H²= X²+ Y²)
Here, K is a conical coefficient, and A and B are fourth-order and sixth-order aspherical coefficients, respectively.

The angle of view in the above embodiment is such that the left and right angles of view are 45 °, the upper and lower angles of view are 34.65 °, and the pupil diameter is 8 mm.
[0063]
FIG. 14 shows a spot diagram similar to FIG. 13 showing the aberration correction state of this embodiment.
Example 3
Third Embodiment A third embodiment will be described with reference to FIG. The configuration of this embodiment is the same as that of the first embodiment.
[0064]
Hereinafter, the configuration parameters of this optical system will be described. The surface number is shown as a surface number of reverse tracking from the position of the exit pupil 2 to the two-dimensional image display element 14. The method of setting the coordinate system, the amount of eccentricity, the method of giving the inclination angle, the radius of curvature of each surface, the surface interval, the refractive index, the Abbe number, and the aspherical shape are the same as those in the first embodiment.

The angle of view in the above embodiment is such that the left and right angles of view are 45 °, the up and down angles of view are 34.65 °, and the pupil diameter is 6 mm.
[0065]
FIG. 15 shows a spot diagram similar to FIG. 13 showing the aberration correction state of this embodiment.
Example 4
Embodiment 4 will be described with reference to FIG. The configuration of this embodiment is almost the same as that of the first embodiment.
[0066]
Hereinafter, the configuration parameters of this optical system will be described. The surface number is shown as a surface number of reverse tracking from the position of the exit pupil 2 to the two-dimensional image display element 14. The method of setting the coordinate system, the amount of eccentricity, the method of giving the inclination angle, the radius of curvature of each surface, the surface interval, the refractive index, the Abbe number, and the aspherical shape are the same as those in the first embodiment.

The angle of view in the above embodiment is such that the left and right angles of view are 50 °, the upper and lower angles of view are 35 °, and the pupil diameter is 8 mm. In the above table, by moving the relay lens system 15 to the numerical values in parentheses of the eccentricity and the inclination angle of the surface number: 5, the left and right observation view angles can be switched from 50 ° to 30 °. I have.
[0067]
FIGS. 16 and 17 show spot diagrams similar to FIG. 13 showing aberration correction states at a wide angle of view and at a narrow angle of view in this embodiment.
Example 5
A fifth embodiment will be described with reference to FIG. The configuration of this embodiment is almost the same as that of the first embodiment.
[0068]
Hereinafter, the configuration parameters of this optical system will be described. The surface number is shown as a surface number of reverse tracking from the position of the exit pupil 2 to the two-dimensional image display element 14. The method of setting the coordinate system, the amount of eccentricity, the method of giving the inclination angle, the radius of curvature of each surface, the surface interval, the refractive index, the Abbe number, and the aspherical shape are the same as those in the first embodiment.
[0069]
In all of Examples 5 to 8 shown below, the bending angle by the ocular concave mirror 3 is 70 °.

The angle of view in the above embodiment is such that the left and right angles of view are 50 °, the upper and lower angles of view are 38.5 °, and the pupil diameter is 10 mm.
[0070]
FIGS. 18 to 20 show spot diagrams similar to FIG. 13 showing the aberration correction state of this embodiment.
Example 6
A sixth embodiment will be described with reference to FIG. The configuration of this embodiment is almost the same as that of the first embodiment.
[0071]
Hereinafter, the configuration parameters of this optical system will be described. The surface number is shown as a surface number of reverse tracking from the position of the exit pupil 2 to the two-dimensional image display element 14. The method of setting the coordinate system, the amount of eccentricity, the method of giving the inclination angle, the radius of curvature of each surface, the surface interval, the refractive index, and the Abbe number are the same as those in the first embodiment. The same applies to the aspherical shape of each surface. However, the relay optical system 15 is represented by the equation of the second embodiment.

The angle of view in the above embodiment is such that the left and right angles of view are 50 °, the upper and lower angles of view are 38.5 °, and the pupil diameter is 10 mm.
Example 7
A seventh embodiment will be described with reference to FIG. The configuration of this embodiment is almost the same as that of the sixth embodiment.
[0072]
Hereinafter, the configuration parameters of this optical system will be described. The surface number is shown as a surface number of reverse tracking from the position of the exit pupil 2 to the two-dimensional image display element 14. The method of setting the coordinate system, the amount of eccentricity, the method of giving the inclination angle, the radius of curvature of each surface, the surface interval, the refractive index, the Abbe number, and the aspherical shape are the same as those in the sixth embodiment.

The angle of view in the above embodiment is such that the left and right angles of view are 50 °, the upper and lower angles of view are 38.5 °, and the pupil diameter is 10 mm.
Example 8
An eighth embodiment will be described with reference to FIG. The configuration of this embodiment is almost the same as that of the sixth embodiment.
[0073]
Hereinafter, the configuration parameters of this optical system will be described. The surface number is shown as a surface number of reverse tracking from the position of the exit pupil 2 to the two-dimensional image display element 14. The method of setting the coordinate system, the amount of eccentricity, the method of giving the inclination angle, the radius of curvature of each surface, the surface interval, the refractive index, the Abbe number, and the aspherical shape are the same as those in the sixth embodiment.

The angle of view in the above embodiment is such that the left and right angles of view are 50 °, the upper and lower angles of view are 35 °, and the pupil diameter is 10 mm.
[0074]
In the case of Examples 5 to 8, the relay optical system 15 can be arranged on the observer's head (upper part of the eyeball), and the eccentricity correction optical system 8 is located above the eyeball. During observation, there is no problem that the eccentricity correction optical system 8 hinders the visual field of the external observation image from being observed. When this problem occurs, when performing other work or moving places while wearing the visual display device, the observer may be worried about the narrow visual field.
[0075]
【The invention's effect】
As is clear from the above description, based on the present invention, it is possible to provide an eccentric optical system for a head-mounted visual display device that can clearly observe a peripheral angle of view with a wide angle of view.
[0076]
Also, it is possible to provide a head-mounted visual display device eccentric optical system capable of clearly observing an aerial image with a wide observation field angle projected on a space while wearing glasses or the like.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a visual display device of the present invention.
FIG. 2 is an optical path diagram of an eccentricity correction optical system according to the present invention.
FIG. 3 is a diagram illustrating a field curvature generated by an eyepiece concave mirror of the visual display device.
FIG. 4 is a diagram showing a state in which a visual field is vignetted by a rotational movement of an eye.
FIG. 5 is a cross-sectional view illustrating an optical configuration according to the first embodiment of the present invention.
FIG. 6 is a cross-sectional view illustrating an optical configuration according to a second embodiment.
FIG. 7 is a sectional view showing an optical configuration of a third embodiment.
FIG. 8 is a sectional view showing an optical configuration of a fourth embodiment.
FIG. 9 is a sectional view showing an optical configuration of a fifth embodiment.
FIG. 10 is a sectional view showing an optical configuration of a sixth embodiment.
FIG. 11 is a sectional view showing an optical configuration of a seventh embodiment.
FIG. 12 is a sectional view showing an optical configuration of an eighth embodiment.
FIG. 13 is a spot diagram showing an aberration correction state according to the first embodiment.
FIG. 14 is a spot diagram showing an aberration correction state according to the second embodiment.
FIG. 15 is a spot diagram showing an aberration correction state according to the third embodiment.
FIG. 16 is a spot diagram showing an aberration correction state in a wide angle of view according to the fourth embodiment.
FIG. 17 is a spot diagram showing an aberration correction state at the time of a narrow angle of view in the fourth embodiment.
FIG. 18 is a part of a spot diagram showing an aberration correction state according to a fifth embodiment.
FIG. 19 is another part of the spot diagram showing the aberration correction state of the fifth embodiment.
FIG. 20 is a remaining diagram of the spot diagram showing the aberration correction state of the fifth embodiment.
FIG. 21 is a plan view showing a configuration of a conventional head-mounted visual display device.
FIG. 22 is a cross-sectional view showing the configuration of a prior art head-mounted visual display device by the present applicant.
[Explanation of symbols]
1 ... Eyeball of observer
2: Observer pupil position
3. Eyepiece concave mirror
4 ... Visual axis of observer
5 Image plane of an object at infinity by an eyepiece concave mirror
6 ... Optical axis bent by eyepiece concave mirror
7: Projection position of pupil of observer
8. Eccentricity correction optical system
9: Optical axis after exiting the eccentricity correction optical system
14 2D image display device
15 ... Relay optical system
18. Image plane corrected by eccentricity correction optical system

Claims (6)

In a decentered optical system including an optical surface decentered at least with respect to the optical axis, disposed between the image plane and the pupil of the observer,
The eccentric optical system includes the at no small, the first transmitting surface, the second transmitting surface, a first reflecting surface and the relay optical system,
The first reflection surface, the first transmission surface and the second transmission surface that are closer to the image surface side than the first reflection surface on the optical path are configured to transmit light from an infinite object point located on the pupil side of the observer. Condensing to form a relay image near the first transmission surface;
The relay optical system projects the relay image on the image plane,
The first reflecting surface is eccentrically arranged with the concave surface facing in the direction in which light rays are reflected, and the shape is not rotationally symmetric, and is configured in an aspherical shape including a rotationally asymmetrical aspherical coefficient,
The first transmission surface and the second transmission surface are arranged in a wedge shape,
Decentered optical system characterized by being configured in a non-spherical shape including a rotationally asymmetric aspherical surface coefficients for correcting the astigmatism not rotationally symmetric generated by said first reflecting surface even without low. In a decentered optical system including an optical surface decentered at least with respect to the optical axis, disposed between the image plane and the pupil of the observer,
The eccentric optical system includes the at no small, the first transmitting surface, the second transmitting surface, a first reflecting surface and the relay optical system,
The first reflection surface, the first transmission surface and the second transmission surface that are closer to the image surface side than the first reflection surface on the optical path are configured to transmit light from an infinite object point located on the pupil side of the observer. Condensing to form a relay image near the first transmission surface;
The relay optical system projects the relay image on the image plane,
The first reflection surface is eccentrically arranged with the concave surface facing the direction in which light rays are reflected, and the surface shape includes both the optical axis incident on the first reflection surface and the optical axis emitted after reflection. A rotationally asymmetric aspherical shape in which the surface shape when the YZ plane is a cross section and the surface shape when the XZ plane perpendicular to the optical axis is a cross section are different from each other. Composed,
The first transmission surface and the second transmission surface are arranged in a wedge shape,
And surface shape when the cross section of the Y-Z plane in order to correct the astigmatism not rotationally symmetric generated by said first reflecting surface even without low, perpendicular on the Y-Z plane and the optical axis X- An eccentric optical system comprising a rotationally asymmetric aspherical shape having different surface shapes from each other when the Z plane is a cross section. Before Stories second transmitting surface is correlated with the first transmitting surface, that is configured rotationally asymmetric aspherical shape to correct the astigmatism not rotationally symmetric generated by at least said first reflecting surface The decentered optical system according to claim 1 or 2, wherein: The first reflecting surface is decentered optical system according to claim 1, characterized in that it is tilted to the straight line of the optical axis that passes through the pupil center. The decentered optical system according to claim 1, wherein the first reflecting surface is configured such that a bending angle when the optical axis is reflected and bent at the reflecting surface is 60 ° or more. Visual display device, wherein said image plane being arranged on the image display device, that it contained a decentered optical system according to any one of claims 1 to 5.

Images