JP2002090691A - Image display device provided with three-dimensional eccentric optical path - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device which enables observation of videos from one image display element in a light state and makes it easy to correct various aberrations by guiding the video to both the eyes, without using half mirrors. SOLUTION: An observation optical system includes a left ocular part 10L, a right ocular part 10R, and an optical path switching part 20, which guides the luminous flux from a single image display element 3 to the left and right ocular parts 10L and 10R, the left and right ocular parts having at least two or more reflecting surfaces 12R (L) and 13R (L) and are constituted with the eccentric optical surfaces of on-axis main light of the left and right ocular parts being arranged almost in parallel to the eccentric optical plane; and the optical path switching part 20 has left and right optical planes arranged symmetrically, so that left and right symmetrical optical paths can be formed and is constituted with the plane with left and right on-axis main light beams in the optical path switching part and the eccentric optical path planes of the left and right ocular parts crossing each other at an arbitrary angle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device having a three-dimensional eccentric optical path, and more particularly to a head or face-mounted image display device capable of being held on the head or face of an observer. .

[0002]

2. Description of the Related Art Conventionally, an image display device for observing an image of one image display element with both eyes is disclosed in Japanese Patent Application Laid-Open No. H6-1100.
No. 13, JP-A-7-287185, JP-A-9-617
No. 48, JP-A-9-181998, JP-A-9-181
No. 999 and Japanese Patent Application Laid-Open No. 10-504115 are known.

[0003]

SUMMARY OF THE INVENTION Among them, Japanese Patent Laid-Open No.
In the device of No. 10013, light rays are split and bent by an isosceles triangular prism and a mirror, so that various aberrations are corrected by a lens arranged in front of a pupil. Causes an increase in size.

In Japanese Patent Application Laid-Open No. Hei 7-287185, a plurality of mirrors are used, and an image is formed by one convex lens. Therefore, assembly adjustment is very difficult, and proper performance cannot be achieved. In addition, although the image display elements are arranged three-dimensionally, the left and right images are rotated in reverse because of the symmetric optical system.

In Japanese Unexamined Patent Application Publication No. 9-61748, display light of an LCD (liquid crystal display element) is split using a half mirror and observed with both eyes. As a result, the display light is divided into the left and right eyeballs, and the observation image becomes weak and dark.

Further, Japanese Patent Application Laid-Open Nos. Hei 9-181998 and Hei 9-181999 have a configuration in which only one reflecting surface is provided, and correction of eccentric aberration is insufficient. It cannot be applied to an image display element that is in use. Furthermore, the angle of view is very narrow.

Further, Japanese Patent Application Laid-Open No. Hei 10-504115 has a very large number of parts and is very complicated to assemble. In this case, since the half mirror is used, the observation image becomes weak and dark.

Further, with the recent miniaturization of image display elements, it is necessary to reduce the focal length of the observation optical system. Further, in order to secure a wide angle of view, the focal length must be shortened. Therefore, it is difficult to secure the back focus, and the optical path in the prism cannot be lengthened. As a result, the number of reflection surfaces cannot be increased, and eccentric aberration cannot be sufficiently corrected.

[0009] Furthermore, the definition of image display elements in recent years has been increasing.

The present invention has been made in view of such problems of the prior art, and an object of the present invention is to guide an image from one image display element to both eyes without using a half mirror and to observe the image brightly. In addition, by using a reflecting surface having four or more curved surfaces in the optical system, it is possible to easily correct various aberrations in order to correspond to recent small and high-definition image display devices. An object of the present invention is to provide an image display device such as a corner-mounted and inexpensive head-mounted image display device. Another object is to further widen the angle of view of an image display device as disclosed in Japanese Patent Application No. 2000-48750.

[0011]

According to the present invention, there is provided an image display apparatus having a three-dimensional eccentric optical path for achieving the above object, comprising: an image display element for forming an observation image on an image display unit; An image display device including an observation optical system for guiding an image to a pupil corresponding to an observer's eyeball position, wherein the image display element has one image display element in which a plurality of pixels are arranged side by side on a single plate. Wherein each pixel located at least in the central portion of the one image display element emits an image light beam at an exit angle capable of guiding the light beam to the left and right eyeballs of the observer. The optical system, at least, a left eyepiece that guides the light beam to the left eye of the observer, a right eyepiece that guides the light beam to the right eye of the observer, and the light emitted from the image display element with the emission angle Light path swing that guides image light flux to the left and right eyepieces And the left eyepiece has at least two or more reflecting surfaces, and at least one of the reflecting surfaces is constituted by a rotationally asymmetric curved reflecting surface having an eccentric aberration correcting function. The right eyepiece has at least two reflecting surfaces, at least one of the reflecting surfaces being a rotationally asymmetric curved reflecting surface having an eccentric aberration correcting function, and the left eyepiece. The decentered optical path surface (YZ) of the axial chief ray formed by the two or more reflecting surfaces of the portion
Eccentric optical path plane (YZ plane) of the axial principal ray formed by the two or more reflecting surfaces of the right eyepiece, and Up and down)
The left and right eyepieces are configured so as to be arranged substantially in parallel (YZ plane), and the optical path distribution unit includes a left and right eyepiece with a center of symmetry between the left eyepiece and the right eyepiece. Optical surfaces are arranged symmetrically so as to form a symmetric optical path, and have at least one set of reflective surfaces on at least the left and right sides. The observation optical system is arranged on an axis to the left reflective surface of the optical path distribution unit. A first plane formed by the incident optical axis and the exit optical axis of the principal ray intersects the eccentric optical path surface of the left eyepiece at an arbitrary angle, and the right reflecting surface of the optical path distribution unit The second eccentric optical path surface of the right eyepiece intersects with a second plane formed by an incident optical axis and an outgoing optical axis of the on-axis principal ray at an arbitrary angle. Optical system that forms an optical path That.

Hereinafter, the reason and operation of the above configuration in the present invention will be described.

In an image display apparatus for observing with the left and right eyes using a single image display element (single-plate binocular vision), when an eccentric optical system is used for the left and right eyepiece optical systems, If an eccentric surface is to be arranged in the horizontal direction, the distance between human pupils is said to be about 64 mm on average, so there is a limit to the space in which the angle of view can be widened. Furthermore, in order to absorb the difference in the interpupillary distance of the observer with the optical system, it is necessary to make the pupil of the optical system horizontal in design. Therefore, if the longitudinal direction of the pupil and the eccentric direction of the eyepiece prism are set to the same direction, it is impossible to achieve a wide angle of view and high performance.

According to the present invention, there is provided an image display including an image display element for forming an observation image on an image display unit, and an observation optical system for guiding an image formed by the image display element to a pupil corresponding to an observer's eyeball position. In the apparatus, the image display element is configured to have one image display element in which a plurality of pixels are arranged side by side on a single plate, and each pixel located at least at a central portion of the one image display element is Is configured to emit an image light beam at an exit angle that can guide the light beam to the left and right eyeballs of the observer, and the observation optical system, at least, a left eyepiece that guides the light beam to the left eye of the observer, A right eyepiece that guides the light beam to the right eye of the observer, and an optical path distribution unit that guides the image light beam emitted from the image display element at the exit angle to the left and right eyepieces, and a left eyepiece Has at least two or more reflective surfaces, among which At least one reflecting surface is composed of rotationally asymmetric curved reflective surface having an eccentric aberration correcting function, right eyepiece portion has at least two surfaces or reflective surfaces,
At least one of the reflecting surfaces is constituted by a rotationally asymmetric curved reflecting surface having an eccentric aberration correcting function. In such an observation optical system, an eccentric optical path plane (Y) of an axial principal ray formed by two or more reflecting surfaces of the left eyepiece unit.
-Z plane, the vertical direction of the observer), and the eccentric optical path plane of the axial chief ray formed by two or more reflecting surfaces of the right eyepiece (YZ plane, This problem is solved by arranging the vertical and horizontal directions substantially parallel (the YZ plane).

In the image display device of the present invention, the cost is very low because one image display element can be viewed with both eyes.

Also, since at least one reflecting surface of each eyepiece is constituted by a rotationally asymmetric curved reflecting surface having an eccentric aberration correcting function, it is possible to correct aberrations well.

In the present invention, a free-form surface is typically used as a rotationally asymmetric curved surface. The free-form surface is defined by the following equation. The Z axis of this definition formula is the axis of the free-form surface.

[0018] Here, the first term of the equation (a) is a spherical term, and the second term is a free-form surface term.

In the spherical term, c: curvature of the vertex k: conic constant (conical constant) r = √ (X ² + Y ² ).

The free-form surface term is Here, C _j (j is an integer of 2 or more) is a coefficient.

The free-form surface is generally an XZ surface,
Neither YZ plane has a symmetry plane, but by setting all odd-order terms of X to 0, a free-form surface having only one symmetry plane parallel to the YZ plane exists. In addition, by setting all odd-order terms of Y to 0, a free-form surface having only one symmetry plane parallel to the XZ plane is obtained.

As another definition of the free-form surface which is the above-mentioned rotationally asymmetric curved surface, it can be defined by a Zernike polynomial. The shape of this surface is defined by the following equation (b). The Z axis of the definition formula (b) is Zernik
e is the axis of the polynomial. The definition of a rotationally asymmetric surface is defined by polar coordinates of the height of the Z axis with respect to the XY plane, where R is XY
A in-plane distance from the Z axis, A is an azimuth around the Z axis, and can be represented by a rotation angle measured from the X axis.

X = R × cos (A) y = R × sin (A) Z = D_Two + D_ThreeRcos (A) + D_FourRsin (A) + D_FiveR^Two cos (2A) + D₆(R^Two-1) + D₇R^Two sin (2A) + D₈R^Threecos (3A) + D₉(3R^Three-2R) cos (A) + D_Ten(3R^Three-2R) sin (A) + D₁₁R^Threesin (3A) + D₁₂R^Fourcos (4A) + D₁₃(4R^Four-3R^Two) Cos (2A) + D₁₄(6R^Four-6R^Two+1) + D_Fifteen(4R^Four-3R^Two) Sin (2A) + D₁₆R^Foursin (4A) + D₁₇R^Fivecos (5A) + D₁₈(5R^Five -4R^Three) Cos (3A) + D₁₉(10R^Five -12R^Three + 3R) cos (A) + D₂₀(10R^Five-12R^Three + 3R) sin (A) + D_{twenty one}(5R^Five -4R^Three) Sin (3A) + D_{twenty two}R^Five sin (5A) + D_{twenty three}R⁶cos (6A) + D_{twenty four}(6R⁶-5R^Four) Cos (4A) + D_{twenty five}(15R⁶-20R^Four+ 6R^Two ) Cos (2A) + D₂₆(20R⁶-30R^Four+ 12R^Two-1) + D₂₇(15R⁶-20R^Four + 6R^Two) Sin (2A) + D₂₈(6R⁶-5R^Four) Sin (4A) + D₂₉R⁶sin (6A) ········ (b) where D_m(M is an integer of 2 or more) is a coefficient. What
To design an optical system symmetrical in the X-axis direction,
D_Four, D_Five, D₆, D_Ten, D₁₁, D₁₂, D₁₃, D₁₄, D
₂₀, D_{twenty one}, D_{twenty two}Use….

The above-mentioned definition formula is shown for the purpose of exemplifying a rotationally asymmetric curved surface, and it goes without saying that the same effect can be obtained for any other definition formula.

As another example of the free-form surface definition formula,
The following definition formula (c) is given.

Z = ΣΣC _nm XY As an example, when k = 7 (seventh-order term) is considered, when expanded, it can be expressed by the following equation.

Z = C ₂ + C ₃ Y + C ₄ | X | + C ₅ Y ² + C ₆ Y | X | + C ₇ X ² + C ₈ Y ³ + C ₉ Y ² | X | + C ₁₀ YX ² + C ₁₁ | X ³ | + C ₁₂ Y ⁴ + C ₁₃ Y ³ | X | + C ₁₄ Y ² X ² + C ₁₅ Y | X ³ | + C ₁₆ X ⁴ + C ₁₇ Y ⁵ + C ₁₈ Y ⁴ | X | + C ₁₉ Y ³ X ² + C ₂₀ Y ² | X ^{_{3 | + C 21 YX 4 +}} C 22 | X 5 | + C 23 Y 6 + C 24 Y 5 | X | + C 25 Y 4 X 2 + C 26 Y 3 | X 3 | + C 27 Y 2 X 4 + C 28 Y | X 5 | ^{_{+ C 29 X 6 + C 30}} Y 7 + C 31 Y 6 | X | + C 32 Y 5 X 2 + C 33 Y 4 | X 3 | + C 34 Y 3 X 4 + C 35 Y 2 | X 5 | + C 36 YX 6 + C 37 | X ⁷ | (c) Note that an anamorphic surface or a toric surface may be used as the rotationally asymmetric curved surface.

Further, in the present invention, an optical path splitting section for guiding an image light beam emitted from the image display element with a wide exit angle to the left and right eyepieces is used, and an optical path splitting optical element such as a half mirror is used. Since it is not used, a bright image can be observed.

Further, by having four or more reflecting surfaces in each of the left and right observation optical paths and forming a relay image (intermediate image), observation with a required short focal length (wide field angle) is possible. The back focus can be ensured even by the optical system, so that an observation optical system having a wide angle of view can be provided, and a high-performance observation optical system accompanying high definition of the image display element can be provided.

When the eyepiece prisms are used as the left and right eyepieces, respectively, the eccentric direction is the vertical direction.
An extremely wide angle of view can be ensured even though the image display device is a single-chip binocular image display.

Since a three-dimensional optical path is used, the optical path length can be increased, and the power of each surface can be set weak. Therefore, it is possible to achieve high performance and loose manufacturing tolerances.

In order to better correct the eccentric aberration of the left and right optical systems, the optical path allocating unit should have at least one set of rotationally asymmetric curved reflecting surfaces having an eccentric aberration correcting function. Is desirable.

More desirably, the optical path allocating portion has at least two or more sets of reflecting surfaces, and at least two or more sets of reflecting surfaces preferably have a rotationally asymmetric curved surface shape having an eccentric aberration correcting function. .

Furthermore, it is desirable that the optical path allocating section has at least three or more sets of reflecting surfaces, and that at least three or more sets of reflecting surfaces have a rotationally asymmetric curved surface shape having an eccentric aberration correcting function.

Further, as in a third embodiment described later, the optical path allocating unit has at least three or more sets of reflecting surfaces, and two or more of the reflecting surfaces have a rotationally asymmetrical function having an eccentric aberration correcting function. It is a curved surface shape, and one set of at least three or more sets of reflecting surfaces is a reflecting surface by a total reflection effect obtained by causing a light beam to enter at an angle larger than the critical angle for total reflection. You can also.

The above-mentioned observation optical system can be constituted by only a reflecting mirror or a combination of a reflecting mirror and a prism member. However, the observation optical system is formed only by a prism member, and both of the reflecting surfaces are formed on the surface of the prism member. It can also be constituted by the formed back reflection surface.

In this case, as in the embodiment described later, the observation optical system is separated from the optical path distributing prism constituting the optical path distributing unit and the optical path distributing prism with an air gap therebetween to form the left eyepiece. And a right eyepiece prism forming a right eyepiece.

In this case, the light path distributing prism has at least an incident surface opposed to the image display element for entering both light beams of the image light beam forming the light path for the left eye and the image light beam forming the light path for the right eye into the prism. A left exit surface that emits a light beam in the left-eye optical path to the outside of the prism, and at least a light beam that is disposed on the optical path between the entrance surface and the left exit surface and reflects the left-eye optical path in the prism. Three or more left-side reflecting surfaces, a right-side exit surface for emitting the light beam of the right-eye optical path out of the prism, and a light beam for the right-eye optical path that is disposed on the optical path between the incident surface and the right-side exit surface. And at least three or more right-side reflecting surfaces reflecting in the prism,
A first plane including an axial principal ray passing through at least three or more left reflecting surfaces and a second plane including an axial principal ray passing through the at least three or more right reflecting faces are substantially in the same plane. Desirably, it is configured to be formed. With this arrangement, the images projected to the left and right eyes do not become images rotated left and right in opposite directions, so that good images can be observed.

The reflecting surface arranged closest to the incident surface on the optical path for the left eye and the reflecting surface arranged closest to the incident surface on the optical path for the right eye are both The image display device and the incident surface can be arranged adjacent to each other so as to be opposed to each other.

In this case, the optical path distributing prism vertically radiates light from the central area of the image display element to the area including the boundary between the left and right reflecting surfaces disposed closest to the light path with respect to the incident surface. It is desirable to provide an anti-reflection member so that the reflected light is not reflected as ghost light.

Further, between the image display element and the optical path allocating section, the light intensity of the image light flux having a predetermined emission angle emitted from each pixel located at least in the central portion of the one image display element is determined. It is desirable to dispose a sorting light enhancing member that makes the intensity of the light beam emitted in the vertical direction of each pixel surface stronger.

In the case where the observation optical system is composed of an optical path distributing prism and left and right eyepiece prisms, both the left eyepiece prism and the right eyepiece prism are arranged in order from the optical path distributing prism side as shown in the embodiment described later. The reflecting surface, the second reflecting surface, and the emitting surface can be configured such that the first reflecting surface and the emitting surface are the same surface, and the first reflecting surface is a reflecting surface by total reflection on the surface. .

In this case, the entrance surfaces of the left eyepiece prism and the right eyepiece prism can be formed in a rotationally asymmetric curved surface shape for correcting eccentric aberration, and the rotationally asymmetric curved surface has only one symmetric surface. It can be composed of a free-form surface provided with

Further, the second reflecting surfaces of the left eyepiece prism and the right eyepiece prism can be formed in a rotationally asymmetric curved surface shape for correcting eccentric aberration, and the rotationally asymmetric curved surface has only one symmetric surface. It can be composed of a free-form surface having only

The observation optical system forms a relay image for the right eye of the image displayed by the image display element in the right optical path, and
It is preferable that a left-eye relay image of the image displayed by the image display element is formed in the left optical path.

When the angle between the axial principal rays of the left and right light beams guided to the observer's eyeball from each pixel located at least in the central portion of the image display element is θ, the following conditional expression is satisfied: It is desirable to do.

20 ° <θ <150 ° (1) This conditional expression is a conditional expression for appropriately separating the image luminous flux for both eyes. In particular, the effective diameters of the left and right first reflection surfaces of the optical path allocating unit arranged closest to the image display element overlap, and the optical system must be enlarged in order to secure the effective diameter. This is not suitable for the optical system of the head or face-mounted image display device. Conversely, if the upper limit of 150 ° is exceeded, an image display device having a very wide viewing angle characteristic is required, and at the same time, the solid angle of the image light beam becomes small, so that a bright image cannot be observed. This angle θ more preferably satisfies the following conditional expression.

25 ° <θ <120 ° (1-1) In the image display device as described above, an image sensor is arranged in place of the image display device, and the pupil passes through the luminous flux from the subject. It can also be used as an imaging device that is configured as an entrance pupil that forms an image of a subject on an imaging element.

Further, a projection object may be arranged in place of the image display element, and a screen may be arranged in front of the pupil, and the projection device may be used as a projection device for forming a projection image of the projection object on the screen.

[0050]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image display device having a three-dimensional eccentric optical path according to the present invention will be described based on embodiments.

In the following examples, the coordinates are taken in such a manner that the visual axis direction (front direction) of the observer is the Z axis, the horizontal direction is the X axis, and the vertical direction is the Y axis.

In the numerical data of each embodiment described later, the observation optical system for the right eye is shown, and is shown by the data of the back ray tracing from the pupil 1R for the right eye to the image display element (image plane) 3. It is. Regarding the observation optical system for the left eye, although numerical data is omitted, it has a plane-symmetric relationship with respect to a symmetry plane passing through the center of a straight line connecting both eyes. The following configuration will be described in the reverse ray tracing order.

FIG. 1 is a diagram showing mainly the optical surface and optical path of the right eye portion of the optical system of the image display apparatus according to the first embodiment. In the figure, (a) is a side view of the optical path for the right eye viewed from the negative direction of the X axis,
(B) is a rear view of the optical path for the right eye viewed from the negative direction of the Z axis,
(C) is a plan view of the optical path for the right eye as viewed from the Y-axis positive direction. FIG. 2 is a plan view of the binocular optical path of the image display device according to the first embodiment viewed from the positive direction of the Y axis. “L” and “R” are given after the reference numerals to distinguish the left and right optical surfaces, the axial chief ray, and the pupil. Also, in order to ensure consistency with the description of the numerical data described below, the order of signing is based on reverse ray tracing. The same applies to other embodiments.

When the observation optical system of this embodiment is configured as a head-mounted image display device, an axial chief ray (light beam) for backward ray tracing, which is emitted from the pupil 1R where the pupil of the observer's right eye should be located. Axis) 2R is the eleventh surface 11 of the right eyepiece prism 10R.
R is refracted by R, enters the eyepiece prism 10R, is internally reflected by the twelfth surface 12R, and is combined with the eleventh surface 11R.
It is incident on the surface 13R at an angle exceeding the critical angle and is totally reflected,
Right eyepiece prism 10R refracted by 14th surface 14R
Out of the optical path distributing prism 20, the light is refracted by the 21st surface 21R for the right eye, enters the optical path distributing prism 20, is internally reflected by the 22nd surface 22R for the right eye, and is reflected by the 23rd surface 2R.
Internally reflected at 3R, internally reflected at 24th surface 24R,
The light is refracted by the 25th surface 25 shared by the left and right eyes, exits from the optical path distribution prism 20, and reaches the image display element 3. The observation optical system for the left eye is similar to the above because it has a plane-symmetric relationship with respect to a symmetry plane passing through the center of a straight line connecting the left and right eyes EL and ER. However, "L" is added instead of "R" after the sign. In the following description, "R" and "L" after the sign are omitted unless otherwise required.

In this embodiment, the eyepiece prism 10 has a two-dimensional eccentric configuration decentered in the YZ plane, and the optical path distribution prism 20 has an axial principal ray incident on its 21st surface 21 and an exit from the 25th surface. The two-dimensional eccentric configuration is decentered in a plane including the on-axis principal ray, and the left and right optical axes of the optical path distribution prism 20 are included in the same plane. However, the plane in which the surface of the eyepiece prism 10 is decentered is orthogonal to the plane in which the surface of the optical path distribution prism 20 is decentered, and the entire observation optical system is three-dimensionally decentered. The same applies to the second and third embodiments.

In this embodiment, when the image display element 3 is 1
The cost is very low because binocular vision is possible with a single sheet. Further, as is apparent from the numerical data described later, since a rotationally asymmetric free-form surface is used except for the eleventh surface 11 of the eyepiece prism 10, the aberration can be favorably corrected. Since a half mirror is not used, a bright image can be observed. Further, five reflecting surfaces are used in each of the left and right optical paths, and further, an intermediate image (relay image) is allocated to the optical path distribution prism 20.
In the vicinity of the twenty-first surface 21, the back focus can be ensured even with the observation optical system having a required short focal length (wide angle of view), and the observation optical system with a wide angle of view can be obtained. It is possible to provide a high-performance observation optical system that accompanies higher definition of a display element.

Further, since the eccentric direction of the eyepiece prism 10 is the vertical direction (YZ plane), an extremely wide angle of view can be ensured in a single-panel binocular display device.

Further, since the observation optical system has a three-dimensional optical path, the optical path length can be increased, and the power of each surface can be set to be weak. Therefore, it is possible to achieve high performance and loose manufacturing tolerances.

Further, in this embodiment, since the total reflection surface is not used for the optical path distribution prism 20, the power of each surface can be appropriately distributed, and the eccentric aberration can be corrected well.

FIG. 3 is a diagram showing mainly the optical surface and optical path of the right eye portion of the optical system of the image display apparatus according to the second embodiment. In the figure, (a) is a side view of the optical path for the right eye viewed from the negative direction of the X axis,
(B) is a rear view of the optical path for the right eye viewed from the negative direction of the Z axis,
(C) is a plan view of the optical path for the right eye as viewed from the Y-axis positive direction. FIG. 4 is a plan view of the binocular optical path of the image display device according to the second embodiment as viewed from the Y-axis positive direction.

When the observation optical system of this embodiment is configured as a head-mounted image display device, when the observer's right (left) eye pupil is located at the pupil 1R (L) where the pupil of the right (left) eye should be located, it is used to trace back rays. The axial principal ray (optical axis) 2R (L) is refracted by the eleventh surface 11R (L) of the right (left) eyepiece prism 10R (L), enters the eyepiece prism 10R (L), and enters the twelfth lens. Surface 12R
(L), the light is internally reflected, enters the thirteenth surface 13R (L) also serving as the eleventh surface 11R (L) at an angle exceeding the critical angle, is totally reflected, is refracted by the fourteenth surface 14R (L), and The light exits from the eyepiece prism 10R (L), is refracted by the right (left) eye 21st surface 21R (L) of the optical path sorting prism 20, enters the optical path sorting prism 20, and enters the right (left) eye 22nd. The surface is internally reflected by the surface 22R (L), and the 23rd surface 23R
The light is internally reflected at (L), internally reflected at the 24th surface 24R (L), refracted by the 25th surface 25 shared by the left and right eyes, exits the optical path sorting prism 20, and reaches the image display element 3.

Also in this embodiment, the eyepiece prism 10
Is a two-dimensional eccentric configuration decentered in the YZ plane, and the optical path distribution prism 20 is decentered in a plane including the axial principal ray incident on the 21st surface 21 and the axial principal ray emitted from the 25th surface. The left and right optical axes of the optical path distribution prism 20 are included in the same plane. However, the plane in which the surface of the eyepiece prism 10 is decentered is orthogonal to the plane in which the surface of the optical path distribution prism 20 is decentered, and the entire observation optical system is three-dimensionally decentered.

In this embodiment, the image display element 3 is 1
The cost is very low because binocular vision is possible with a single sheet. Further, as is apparent from the numerical data described later, since a rotationally asymmetric free-form surface is used except for the eleventh surface 11 of the eyepiece prism 10, the aberration can be favorably corrected. Since a half mirror is not used, a bright image can be observed. Further, five reflecting surfaces are used in each of the left and right optical paths, and further, an intermediate image (relay image) is allocated to the optical path distribution prism 20.
In the vicinity of the twenty-first surface 21, the back focus can be ensured even with the observation optical system having a required short focal length (wide angle of view), and the observation optical system with a wide angle of view can be obtained. It is possible to provide a high-performance observation optical system that accompanies higher definition of a display element.

Further, since the eccentric direction of the eyepiece prism 10 is in the vertical direction (YZ plane), a very wide angle of view can be ensured in a single-panel binocular display device.

Further, since the observation optical system has a three-dimensional optical path, the optical path length can be increased, and the power of each surface can be set weak. Therefore, it is possible to achieve high performance and loose manufacturing tolerances.

In this embodiment, since the optical path allocating prism 20 does not use a total reflection surface, the power of each surface can be appropriately distributed, and eccentric aberration can be corrected well.

The second embodiment and the first embodiment are different from the 24th surface 2
4R (L) is only changed, and by arranging it on the right side (left side in the first embodiment) of the eye radiation center of the observer in the optical path for the right eye in FIG. There is an advantage in that it can be made smaller.

FIG. 5 is a diagram showing mainly the optical surface and optical path of the right eye portion of the optical system of the image display apparatus according to the third embodiment. In the figure, (a) is a side view of the optical path for the right eye viewed from the negative direction of the X axis,
(B) is a rear view of the optical path for the right eye viewed from the negative direction of the Z axis,
(C) is a plan view of the optical path for the right eye as viewed from the Y-axis positive direction. FIG. 5 is a plan view of the binocular optical path of the image display device according to the third embodiment viewed from the positive direction of the Y axis.

When the observation optical system of this embodiment is configured as a head-mounted image display device, when the observer's right (left) eye pupil is located at the pupil 1R (L) where the pupil of the right (left) eye should be located, the ray tracing is performed. The axial principal ray (optical axis) 2R (L) is refracted by the eleventh surface 11R (L) of the right (left) eyepiece prism 10R (L), enters the eyepiece prism 10R (L), and enters the twelfth lens. Surface 12R
(L), the light is internally reflected, enters the thirteenth surface 13R (L) also serving as the eleventh surface 11R (L) at an angle exceeding the critical angle, is totally reflected, is refracted by the fourteenth surface 14R (L), and The light exits from the eyepiece prism 10R (L), is refracted by the right (left) eye 21st surface 21R (L) of the optical path sorting prism 20, enters the optical path sorting prism 20, and enters the right (left) eye 22nd. The surface is internally reflected by the surface 22R (L), and the 21st surface 21R
(L) is incident on the 23rd surface 23R (L) also serving as an angle exceeding the critical angle, is totally reflected, is internally reflected by the 24th surface 24R (L), and is refracted by the 25th surface 25 shared by the left and right eyes. The light exits from the optical path sorting prism 20 and reaches the image display element 3.

Also in this embodiment, the eyepiece prism 10
Is a two-dimensional eccentric configuration decentered in the YZ plane, and the optical path distribution prism 20 is decentered in a plane including the axial principal ray incident on the 21st surface 21 and the axial principal ray emitted from the 25th surface. The left and right optical axes of the optical path distribution prism 20 are included in the same plane. However, the plane in which the surface of the eyepiece prism 10 is decentered is orthogonal to the plane in which the surface of the optical path distribution prism 20 is decentered, and the entire observation optical system is three-dimensionally decentered.

In this embodiment, the image display element 3 is 1
The cost is very low because binocular vision is possible with a single sheet. Further, as is apparent from the numerical data described later, since a rotationally asymmetric free-form surface is used except for the eleventh surface 11 of the eyepiece prism 10, the aberration can be favorably corrected. Since a half mirror is not used, a bright image can be observed. Further, five reflecting surfaces are used in each of the left and right optical paths, and further, an intermediate image (relay image) is allocated to the optical path distribution prism 20.
In the vicinity of the twenty-first surface 21, the back focus can be ensured even with the observation optical system having a required short focal length (wide angle of view), and the observation optical system with a wide angle of view can be obtained. It is possible to provide a high-performance observation optical system that accompanies higher definition of a display element.

Further, since the eccentric direction of the eyepiece prism 10 is in the vertical direction (YZ plane), a very wide angle of view can be ensured in spite of the single-panel binocular display device.

Further, since the observation optical system has a three-dimensional optical path, the optical path length can be increased, and the power of each surface can be set weak. Therefore, it is possible to achieve high performance and loose manufacturing tolerances.

In this embodiment, the optical path is folded by using the dual surface of the 21st surface 21R (L) of the refraction surface and the 23rd surface 23R (L) of the total reflection surface of the optical path distribution prism 20. It is possible to make the Y direction (the vertical direction of the observer) smaller.

In all of the first to third embodiments, the light path distributing prism 20 is used. However, as a modification, the light beam emitted from the eyepiece prism 10 is similarly reflected once by a mirror, and thereafter the light path distributing prism 20 is used. 20 may be used. With this configuration, the size of the optical path sorting prism 20 is reduced, and the weight of the apparatus can be reduced.

Next, the configuration parameters of the first to third embodiments will be described. In the configuration parameters of each embodiment, for example, as shown in FIG. 1, in the reverse ray tracing, the axial principal ray 2 passes through the center of the exit pupil 1 of the optical system vertically and reaches the center of the image display element 3. Define. In the reverse ray tracing, the center of the pupil 1 is defined as the origin of the decentered optical surface of the decentered optical system, the direction along the axial principal ray 2 is defined as the Z-axis direction, and the direction from the pupil 1 toward the eleventh surface 11 is defined as the positive Z-axis. A plane in which the optical axis is bent in the eyepiece prism 10 is a YZ plane, a direction perpendicular to the YZ plane through the origin, and a direction from right to left in the horizontal direction is an X-axis positive direction, and an X-axis , The axis constituting the right-handed rectangular coordinate system with the Z axis is the Y axis. Therefore, the direction from the bottom to the top in the vertical direction is the Y-axis positive direction.

For the eccentric surface, the amount of eccentricity from the center of the origin of the optical system to the top of the surface (X-axis direction, Y-axis direction, Z-axis direction)
The axial directions are X, Y, and Z, respectively, and the X-axis of the center axis of the surface (for a free-form surface, the Z-axis of the formula (a), and for an aspheric surface, the Z-axis of the formula (d) described later) , Y-axis, and Z-axis tilt angles (α, β, γ (°), respectively)
And is given. In this case, the positive α and β mean counterclockwise with respect to the positive direction of each axis, and the positive γ means clockwise with respect to the positive direction of the Z axis. The rotation of the center axis of the surface by α, β, γ depends on the center axis of the surface and its XYZ.
The orthogonal coordinate system is first rotated counterclockwise by α around the X axis, and then the center axis of the rotated surface is changed to Y in the new coordinate system.
The coordinate system rotated counterclockwise around the axis by β and rotated once is also rotated counterclockwise around the Y axis by β, and then the center axis of the surface rotated twice is added to the new coordinate system. This is to make a γ rotation clockwise around the Z axis of a simple coordinate system.

Further, among the optical working surfaces constituting the optical system of each embodiment, when a specific surface and a subsequent surface constitute a coaxial optical system, a surface interval is given, and in addition, a medium spacing is given. The refractive index and Abbe number are given according to a conventional method.

Further, the shape of the surface of the free-form surface used in the present invention is defined by the above equation (a), and the Z axis of the definition expression is the axis of the free-form surface.

The aspherical surface is a rotationally symmetric aspherical surface given by the following definitional expression.

Z = (y ² / R) / [1+ ｛1− (1 + K) y ² / R ² ｝ ^1/2 ] + Ay ⁴ + By ⁶ + Cy ⁸ + Dy ¹⁰ +... (D) Is the optical axis (on-axis principal ray) where the traveling direction of light is positive, and y is a direction perpendicular to the optical axis. Here, R is a paraxial radius of curvature, K is a conic constant, and A, B, C, D,... Are fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients, respectively.
The Z axis of this definition expression is the axis of the rotationally symmetric aspherical surface.

The term relating to a free-form surface or aspherical surface for which no data is described is zero. Regarding the refractive index,
The values for the d-line (wavelength 587.56 nm) are shown. The unit of the length is mm.

In Examples 1 to 3, when the observation optical system is used, the observation angle of view is 17.5 ° in the horizontal half angle of view, 13.3 ° in the vertical half angle of view, and the pupil diameter is 4 mm.

Note that “F” in the following configuration parameter table
“FS” indicates a free-form surface, “ASS” indicates an aspherical surface, and “RE” indicates a reflective surface.

(Example 1) Surface number Curvature radius Surface distance Eccentricity Refractive index Abbe number Object plane ∞-1000.00 1 ∞ (pupil) 2 ASS Eccentricity (1) 1.5254 56.2 3 FFS (RE) Eccentricity (2) 1.5254 56.2 4 ASS (RE) Eccentricity (1) 1.5254 56.2 5 FFS Eccentricity (3) 6 FFS Eccentricity (4) 1.5254 56.2 7 FFS (RE) Eccentricity (5) 1.5254 56.2 8 FFS (RE) Eccentricity (6) 1.5254 56.2 9 FFS (RE) Eccentricity (7) 1.5254 56.2 10 FFS Eccentricity (8) Image plane ∞ Eccentricity (9) ASS R -165.42 K 0.0000 A -5.2477 × 10 ^-7 B 5.9890 × 10 ^-10 FFS C ₄ -9.0776 × 10 ^-3 C _6- 8.8020 × 10 ^-3 C ₈ 2.4862 × 10 ^-5 C ₁₀ 4.5 192 × 10 ^-5 C ₁₁ -1.1138 × 10 ^-6 C ₁₃ -2.2393 × 10 ^-6 C ₁₅ -1.4980 × 10 ^-6 C ₁₇ 6.2564 × 10 ^-9 C ₁₉ 7.3888 × 10 ^-8 C ₂₁ 4.9912 × 10 ^-8 FFS C ₄ -2.5 220 × 10 ^-4 C ₆ -5.6 446 × 10 ^-3 C ₈ 6.9 828 × 10 ^-5 C ₁₀ -2.8905 × 10 ^-5 C ₁₁ 7.7931 × _{^{10 -6 C 13 1.1521 × 10 -5}} C 17 -5.3841 × 10 -8 C 19 -2.0288 × 10 -6 FFS C 4 6.1642 _{^{10 -3 C 6 -2.0908 × 10 -2}} FFS C 4 -1.6314 × 10 -4 C 6 -5.1139 × 10 -3 C 7 4.6746 × 10 -5 C 9 2.2166 × 10 -4 FFS C 4 3.1220 × 10 -3 C ₆ 2.5978 × 10 ^-3 C ₇ -1.0497 × 10 ^-5 C ₉ -3.4853 × 10 ^-5 FFS C ₄ -4.5998 × 10 ^-3 C ₆ -6.9956 × 10 ^-3 C ₇ 2.4794 × 10 ^-5 C ₉ 6.7926 × 10 ^-6 FFS C ₄ 6.2397 × 10 ^-3 C ₆ 2.2258 × 10 ^-2 Eccentricity (1) X 0.00 Y 7.22 Z 27.80 α 18.61 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.84 Z 38.64 α -12.47 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 18.30 Z 32.34 α 85.56 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 23.38 Z 35.55 α 57.70 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 32.53 Z 41.33 α 57.70 β 53.86 γ 0.00 Eccentricity (6) X 54.10 Y 47.13 Z 50.57 α 57.70 β 70.96 γ 0.00 Eccentricity (7) X 38.62 Y 66.39 Z 62.74 α 57.70 β 11.88 γ 0.00 Eccentricity (8) X 30.00 Y 30.98 Z 40.35 α 57.70 β 0.00 γ 0.00 Eccentricity 9) X 30.00 Y 28.40 Z 38.72 α 57.70 β 0.00 γ 0.00.

(Example 2) Surface number Curvature radius Surface distance Eccentricity Refractive index Abbe number Object plane ∞-1000.00 1 ∞ (pupil) 2 ASS Eccentricity (1) 1.5254 56.2 3 FFS (RE) Eccentricity (2) 1.5254 56.2 4 ASS (RE) Eccentricity (1) 1.5254 56.2 5 FFS Eccentricity (3) 6 FFS Eccentricity (4) 1.5254 56.2 7 FFS (RE) Eccentricity (5) 1.5254 56.2 8 FFS (RE) Eccentricity (6) 1.5254 56.2 9 FFS (RE) Eccentricity (7) 1.5254 56.2 10 FFS Eccentricity (8) Image plane ∞ Eccentricity (9) ASS R -165.42 K 0.0000 A -5.2477 × 10 ^-7 B 5.9890 × 10 ^-10 FFS C ₄ -9.0776 × 10 ^-3 C _6- 8.8020 × 10 ^-3 C ₈ 2.4862 × 10 ^-5 C ₁₀ 4.5 192 × 10 ^-5 C ₁₁ -1.1138 × 10 ^-6 C ₁₃ -2.2393 × 10 ^-6 C ₁₅ -1.4980 × 10 ^-6 C ₁₇ 6.2564 × 10 ^-9 C ₁₉ 7.3888 × 10 ^-8 C ₂₁ 4.9912 × 10 ^-8 FFS C ₄ -2.5 220 × 10 ^-4 C ₆ -5.6 446 × 10 ^-3 C ₈ 6.9 828 × 10 ^-5 C ₁₀ -2.8905 × 10 ^-5 C ₁₁ 7.7931 × 10 ^-6 C ₁₃ 1.1521 × 10 ^-5 C ₁₇ -5.3841 × 10 ^-8 C ₁₉ -2.0288 × 10 ^-6 FFS C ₄ -1.1136 _{^{× 10 -2 C 6 -1.4190 × 10}} -2 FFS C 4 -8.9818 × 10 -4 C 6 -6.4965 × 10 -3 C 7 7.8485 × 10 -6 C 9 8.5865 × 10 -5 FFS C 4 3.7511 × 10 - ³ C ₆ 3.1246 × 10 ^-3 C ₇ -1.4474 × 10 ^-6 C ₉ -1.4795 × 10 ^-5 FFS C ₄ -4.1361 × 10 ^-3 C ₆ -6.6819 × 10 ^-3 C ₇ 3.3746 × 10 ^-5 C ₉ 2.1533 × 10 ^-5 FFS C ₄ 2.5510 × 10 ^-3 C ₆ 7.0 800 × 10 ^-3 Eccentricity (1) X 0.00 Y 7.22 Z 27.80 α 18.61 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.84 Z 38.64 α -12.47 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 18.30 Z 32.34 α 85.56 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 28.35 Z 38.69 α 57.70 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 37.85 Z 44.70 α 57.70 β 57.67 γ 0.00 Eccentricity (6) X 49.14 Y 57.52 Z 57.13 α 57.70 β 86.25 γ 0.00 Eccentricity (7) X 23.75 Y 71.37 Z 65.89 α 57.70 β 32.78 γ 0.00 Eccentricity (8) X 30.00 Y 39.43 Z 45.70 α 57.70 β 0.00 γ 0.00 Eccentricity (9) X 30.00 Y 36.96 Z 44.13 α 57.70 β 0.00 γ 0.00.

(Example 3) Surface number Curvature radius Surface distance Eccentricity Refractive index Abbe number Object plane ∞-1000.00 1 ∞ (pupil) 2 ASS Eccentricity (1) 1.5254 56.2 3 FFS (RE) Eccentricity (2) 1.5254 56.2 4 ASS (RE) Eccentricity (1) 1.5254 56.2 5 FFS Eccentricity (3) 6 ASS Eccentricity (4) 1.5254 56.2 7 FFS (RE) Eccentricity (5) 1.5254 56.2 8 ASS (RE) Eccentricity (4) 1.5254 56.2 9 FFS (RE) Eccentricity (6) 1.5254 56.2 10 FFS Eccentricity (7) Image plane ∞ Eccentricity (8) ASS R -165.42 K 0.0000 A -5.2477 × 10 ^-7 B 5.9890 × 10 ^-10 ASS R 382.62 K 0.0000 A 5.3231 × 10 ^-6 B -2.0474 × 10 ^-8 FFS C ₄ -9.0776 × 10 ^-3 C ₆ -8.8020 × 10 ^-3 C ₈ 2.4862 × 10 ^-5 C ₁₀ 4.5 192 × 10 ^-5 C ₁₁ -1.1138 × 10 ^-6 C ₁₃ -2.2393 × 10 ^-6 C ₁₅ -1.4 980 × 10 ^-6 C ₁₇ 6.2564 × 10 ^-9 C ₁₉ 7.3888 × 10 ^-8 C ₂₁ 4.9912 × 10 ^-8 FFS C ₄ -2.5 220 × 10 ^-4 C ₆ -5.6446 × 10 ^-3 C _{^{8 6.9828 × 10 -5 C 10 -2.8905}} × 10 -5 C 11 7.7931 × 10 -6 C 13 1.1521 × 10 - ⁵ C ₁₇ -5.3841 × 10 ^-8 C ₁₉ -2.0288 × 10 ^-6 FFS C ₄ -9.6972 × 10 ^-4 C ₆ -1.2267 × 10 ^-2 C ₇ 1.6287 × 10 ^-4 C ₉ -8.6436 × 10 ^-4 FFS C ₄ -1.0906 × 10 ^-2 C ₆ -1.4 106 × 10 ^-2 C ₇ 5.2490 × 10 ^-5 C ₉ 7.0531 × 10 ^-5 FFS C ₄ 1.7442 × 10 ^-2 C ₆ 3.6768 × 10 ^-3 Eccentricity (1) X 0.00 Y 7.22 Z 27.80 α 18.61 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.84 Z 38.64 α -12.47 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 18.30 Z 32.34 α 85.56 β 0.00 γ 0.00 Eccentricity (4) X 11.26 Y 21.18 Z 34.16 α 57.70 β -3.54 γ 0.00 Eccentricity (5) X 0.30 Y 29.41 Z 39.36 α 57.70 β 23.22 γ 0.00 Eccentricity (6) X 38.29 Y 36.90 Z 44.09 α 57.70 β -33.57 γ 0.00 Eccentricity (7) X 32.00 Y 17.98 Z 32.13 α 57.70 β 0.00 γ 0.00 Eccentricity (8) X 32.00 Y 14.09 Z 29.67 α 57.70 β 0.00 γ 0.00.

The value of θ in the conditional expression (1) in the above embodiment is as follows.

Example θ 1 32.8 ° 2 25.9 ° 3 39.8 ° By the way, in the image display apparatus of the present invention, the display light fluxes having a certain spread of emission angles emitted from the single image display element 3 are transmitted to the left and right optical paths. And incident on the entrance surface 25 (Examples 1 to 3) of the optical path sorting prism 20;
As shown in FIG. 7A, the left and right common image display elements 3 are uniformly illuminated by a white backlight 32 as shown in FIG. 7A. Then, the image display element 3 composed of the liquid crystal display element 31 for emitting the display light beam at an emission angle larger than the angle θ (the conditional expression (1)) formed between the optical axes of the left and right optical paths is used. In addition, EL having a large display emission angle
A self-luminous element such as an element can be used as the image display element 3.

In the case where the image display element 33 having a small display emission angle is used as the image display element 3, FIG.
As shown in (b), as a distribution light enhancing member for increasing the emission angle of the display emitted from each pixel 34 in the left and right optical path directions instead of the vertical direction, for example, a light beam distribution microprism having a cross section as shown in the drawing 35 to each pixel 34
It is desirable to arrange them in accordance with. Instead, 0
A transmission diffraction grating configured to weaken the intensity of the second-order transmitted light and increase the ± first-order diffracted light may be arranged close to the display surface of the image display element 3.

By the way, the display luminous flux emitted from the image display element 3 hits the boundary portion 29 between the left and right reflection surfaces 24L and 24R arranged on the optical path closest to the image display element 3 of the optical path distribution prism 20. Then, there is a possibility that the light is reflected there and becomes ghost light. Therefore, FIG.
As shown in (c), a black paint is applied or diffused as an anti-reflection member 36 for preventing such reflection in the vicinity of the boundary portion 29, and the display light flux 37 emitted from the image display element 3 is applied. It is desirable to absorb the light flux portion indicated by the broken line incident on the middle boundary portion 29. The light beam portion indicated by the solid line in the display light beam 37 is guided to the left and right optical paths and represents a light beam used effectively for display.

By supporting the observation optical system as described above, it is possible to construct an image display device to be mounted on both eyes, as a stationary or portable image display device that can be observed by both eyes. Can be configured.

FIG. 8 shows this state. In the figure, reference numeral 131 denotes a display device main body, and a support member is fixed via a head so as to be held in front of both eyes of the observer's face. As the supporting member, one end is joined to the display device main body 131, left and right front frames 132 extending from the temple of the observer to the upper part of the ears, and joined to the other end of the front frame 132 to be connected to the observer. A left and right rear frame 133 extending across the head, and a top frame 134 supporting one end of the left and right rear frames 133 by joining the two ends thereof one by one so as to be sandwiched between the other ends of the left and right rear frames 133; It is composed of

A rear plate 135 made of an elastic material and made of, for example, a metal plate spring is joined to the front frame 132 near the joint with the rear frame 133. The rear plate 135 is joined so that the rear cover 136, which carries one wing of the support member, is positioned behind the ear at the part where the back cover of the observer is attached to the neck of the observer and can be supported. A speaker 139 is mounted in the rear plate 135 or the rear cover 136 at a position corresponding to the ear of the observer.

A cable 141 for transmitting a video / audio signal or the like from the outside is connected to a top frame 134, a rear frame 133, a front frame 132,
Through the inside of the rear plate 135, the rear plate 135
Alternatively, it protrudes outside from the rear end of the rear cover 136. The cable 141 is connected to the video playback device 1
40. In the figure, reference numeral 140a denotes a switch and a volume adjusting unit of the video reproducing apparatus 140.

The cable 141 may be jacked at the end so that it can be attached to an existing video deck or the like. Furthermore, it is connected to a tuner for TV radio wave reception,
It may be used for viewing, or may be connected to a computer to receive computer graphics images, message images from the computer, and the like. In addition, an antenna may be connected to receive an external signal by radio wave in order to reject an obstructive code.

The observation optical system of the image display apparatus of the present invention forms an image by introducing light from a subject from the pupil 1 (1R or 1L) side and arranging an image sensor at the position of the image display element 3. It can also be used as an optical system. FIG. 9 shows a conceptual diagram of a configuration in which the optical system of only one of the left and right sides of the observation optical system of the present invention is incorporated in the photographing objective optical system 42 of the photographing unit of the electronic camera 40. Of course, both left and right optical systems of the observation optical system of the present invention may be used (the entrance pupil becomes two optical systems). In the case of this example, the objective optical system 42 for imaging arranged on the optical path 41 for imaging uses the same optical system as that of the second embodiment with the optical path reversed, and the stop 1 ′ is located at the position of the pupil 1. Have been placed. The object image formed by the photographing objective optical system 42 is formed on an imaging surface 46 of a CCD 45 via a filter 44 such as a low-pass filter or an infrared cut filter. The object image received by the CCD 45 is passed through a processing unit 51 to a liquid crystal display (LC).
D) Displayed on 52 as an electronic image. The processing unit 51 also controls a recording unit 54 that records an object image captured by the CCD 45 as electronic information. LCD 52
Is guided to the observer's eyeball E via an eyepiece optical system 53 composed of an eccentric prism similar to the eyepiece prism 10. As the eyepiece optical system 53, a three-dimensional decentered optical system including the one-side eyepiece prism 10 and the optical path distribution prism 20 according to the present invention may be used. The photographing objective optical system 42 may include another lens (positive lens, negative lens) on the object side of the prism 10 or on the image side of the prism 20 as a component thereof.

In the camera 40 constructed as described above, the photographing objective optical system 42 can be constituted by a small number of optical members, the whole apparatus can be reduced in size, the cost is low, and the dead space is taken into consideration with other members. And the degree of freedom of design is increased.

In this embodiment, a parallel flat plate is disposed as the cover member 43 of the photographing objective optical system 42, but a lens having power may be used.

The optical system having only one of the left and right sides of the observation optical system according to the present invention has an image plane for projection arranged at the position of the image display element 3 and a screen arranged in front of the pupil 1 for projecting optics. It can also be used as a system. Of course, in this case, both the left and right optical systems of the observation optical system of the present invention may be used (the number of exit pupils is two). FIG.
FIG. 0 shows a conceptual diagram of a configuration using a decentered prism optical system according to the present invention as a projection optical system 96 of a presentation system in which a personal computer 90 and a liquid crystal projector 91 are combined. In this example, an optical system similar to that of the second embodiment is used as the projection optical system 96. In FIG.
The image / document data created on the screen 0 branches from the monitor output and is output to the processing control unit 98 of the liquid crystal projector 91. In the processing control unit 98 of the liquid crystal projector 91,
This input data is processed and the liquid crystal panel (LC
P) 93. The liquid crystal panel 93 displays an image corresponding to the input image data. And the light source 9
After the amount of light transmitted from the liquid crystal panel 2 is determined by the gradation of the image displayed on the liquid crystal panel 93, the field lens 95 disposed immediately before the liquid crystal panel 93 and the prisms 20 and 10 constituting the optical system of the present invention. Cover lens 9 for positive lens
4 is projected onto a screen 97 via a projection optical system 96 composed of

The projector configured as described above can be configured with a small number of optical members, and can realize cost reduction and downsizing.

The image display device having the above-described three-dimensional eccentric optical path of the present invention can be constituted, for example, as follows.

[1] An image display device including an image display element for forming an observation image on an image display unit and an observation optical system for guiding an image formed by the image display element to a pupil corresponding to the position of an observer's eyeball. The image display element is configured to have one image display element in which a plurality of pixels are arranged side by side on a single plate, and each pixel located at least at a central portion of the one image display element is The observation optical system is configured to emit an image light beam at an exit angle that can guide the light beam to the left and right eyeballs of the observer, and the observation optical system includes at least a left eyepiece unit that guides the light beam to the left eye of the observer; A right eyepiece that guides a light beam to the right eye of the eye, and an optical path distribution unit that guides an image light beam emitted from the image display element at the emission angle to the left and right eyepieces, and the left eyepiece. Has at least two or more reflective surfaces, among which At least one reflecting surface is formed of a rotationally asymmetric curved reflecting surface having an eccentric aberration correcting function, and the right eyepiece has at least two or more reflecting surfaces, and at least one reflecting surface therein. Is constituted by a rotationally asymmetric curved reflecting surface having an eccentric aberration correcting function, and an eccentric optical path surface (YZ) of an axial principal ray formed by the two or more reflecting surfaces of the left eyepiece. Eccentric optical path plane (YZ plane) of the axial principal ray formed by the two or more reflecting surfaces of the right eyepiece, and The left and right eyepieces are configured such that the right and left eyepieces are arranged substantially in parallel (in the YZ plane). To form a bilaterally symmetric optical path with
An optical surface is disposed symmetrically to the left and right, and at least one pair of reflection surfaces is provided on the left and right sides. The observation optical system is configured such that an incident optical axis and an emission light of an axial chief ray on the left reflection surface of the optical path distribution unit. A first plane formed by an axis and the eccentric optical path surface of the left eyepiece intersect at an arbitrary angle, and incident light of an axial principal ray on the right reflective surface of the optical path distribution unit An optical system that forms a three-dimensionally decentered optical path by intersecting a second plane formed by an axis and an emission optical axis with the eccentric optical path surface of the right eyepiece at an arbitrary angle. An image display device provided with a three-dimensional eccentric optical path, characterized in that:

[2] In the above item 1, the optical path allocating unit is provided with at least one pair of rotationally asymmetric curved reflecting surfaces having an eccentric aberration correcting function. Image display device.

[3] In the above item 1, the optical path allocating portion has at least two or more sets of reflecting surfaces, and the at least two or more sets of reflecting surfaces have a rotationally asymmetric curved surface shape having an eccentric aberration correcting function. An image display device provided with a three-dimensional eccentric optical path.

[4] In the above item 1, the optical path allocating section has at least three or more sets of reflecting surfaces, and the at least three or more sets of reflecting surfaces have a rotationally asymmetric curved surface shape having an eccentric aberration correcting function. An image display device provided with a three-dimensional eccentric optical path.

[5] In the above item 1, the optical path allocating portion has at least three or more sets of reflecting surfaces, and two or more of the reflecting surfaces have a rotationally asymmetric curved surface shape having an eccentric aberration correcting function. In one embodiment, one of the at least three or more sets of reflecting surfaces is a reflecting surface by a total reflection effect obtained by causing a light beam to enter at an angle larger than a critical angle for total reflection. An image display device having a three-dimensional eccentric optical path.

[6] In any one of the above items 1 to 5, the observation optical system may be formed of a prism member, and any of the reflection surfaces may be formed on a back reflection surface formed on the surface of the prism member. An image display device provided with a three-dimensional eccentric optical path characterized by comprising:

[7] In the above-mentioned item 6, the observation optical system is configured such that the optical path distributing prism constituting the optical path distributing unit is separated from the optical path distributing prism with an air gap therebetween, and the left optical part constituting the left eyepiece unit is provided. An image display device having a three-dimensional eccentric optical path, comprising: an eyepiece prism and a right eyepiece prism forming the right eyepiece.

[8] In the above-mentioned item 7, the optical path allocating prism may be configured so that at least the image light beam facing the image display element and forming the left-eye light path and the image light beam forming the right-eye light path are transmitted through the prism. Incident surface, the left exit surface for emitting the light beam of the optical path for the left eye out of the prism, and disposed on the optical path between the entrance surface and the left exit surface, and the optical path for the left eye At least three or more left reflecting surfaces for reflecting the light beam in the prism, a right exit surface for emitting the light beam of the optical path for the right eye out of the prism, and light between the incident surface and the right exit surface. At least three or more right-side reflecting surfaces that are disposed on a road and reflect the light flux of the right-eye optical path in the prism, and form an axial principal ray passing through the at least three or more left-side reflecting surfaces. 1st flat including And a second plane including an axial chief ray passing through at least the three or more right-side reflecting surfaces is formed in substantially the same plane. Image display device provided.

[0111]

[9] In the above item 8, the reflection surface arranged at a position closest to the incident surface on the optical path for the left eye, and the reflection surface arranged at a position closest to the optical path for the right eye with respect to the incident surface. An image display device having a three-dimensional eccentric optical path, wherein a surface is disposed adjacent to both the image display element and the incident surface so as to oppose each other.

[10] In the above-mentioned item 9, the optical path distributing prism may be arranged such that the light path distributing prism moves the image display element to a region including a boundary portion between the left and right reflecting surfaces disposed closest to the light incident surface on the optical path. An image display device having a three-dimensional eccentric optical path, wherein an anti-reflection member is provided so that a light beam emitted vertically from a central region is not reflected as ghost light.

[11] In any one of the above items 1 to 10, light emitted from each pixel located at least in the central portion of the one image display element between the image display element and the optical path allocating section. A three-dimensional eccentric optical path characterized by arranging a distribution light enhancing member so as to make the light intensity of the image light beam having a predetermined exit angle greater than the light intensity emitted in the vertical direction of each pixel surface. Image display device.

[12] In any one of the above-mentioned items 7 to 11, both the left eyepiece prism and the right eyepiece prism are arranged in order from the side of the optical path distribution prism, the entrance surface, the first reflection surface, and the second reflection surface. An emission surface, wherein the first reflection surface and the emission surface are made of the same surface, and the first reflection surface is a reflection surface by total reflection on the surface, and has a three-dimensional eccentric optical path. Image display device.

[13] The three-dimensional decentered optical path according to the above item 12, wherein the entrance surfaces of the left eyepiece prism and the right eyepiece prism are formed in a rotationally asymmetric curved surface shape for correcting eccentric aberration. An image display device comprising:

[14] In the above item 13, the rotationally asymmetric curved surface of the entrance surface of each of the left eyepiece prism and the right eyepiece prism is a free curved surface having only one symmetric surface. An image display device having a three-dimensional eccentric optical path characterized by the above-mentioned.

[15] In any one of the above items 12 to 14, the second reflecting surfaces of the left eyepiece prism and the right eyepiece prism are formed in a rotationally asymmetric curved surface shape for correcting eccentric aberration. An image display device provided with a three-dimensional eccentric optical path.

[16] In the above item 15, the rotationally asymmetric curved surface of the left reflecting surface of the left eyepiece prism and the second reflecting surface of the right eyepiece prism is a free curved surface having only one symmetric surface. An image display device having a three-dimensional eccentric optical path.

[17] In any one of the above items 1 to 16, the observation optical system may form a right-eye relay image of the image displayed by the image display element in the right optical path, and
An image display device having a three-dimensional eccentric optical path, wherein a left-eye relay image of the image displayed by the image display element is formed in the left optical path.

[18] In any one of the above items 1 to 17, the angle formed between the axial principal rays of the left and right light beams guided to the eyeball of the observer from each pixel located at least in the central portion of the image display element. Is an image display device satisfying the following conditional expression:

20 ° <θ <150 ° (1) [19] Imaging is performed in place of the image display element of the image display device including the three-dimensional eccentric optical path according to any one of the above items 1 to 18. An image pickup apparatus, comprising: an element arranged; an entrance pupil through which a light beam from a subject passes; and an image of the subject formed on the image pickup element.

[20] A projection object is arranged in place of the image display element of the image display device having the three-dimensional eccentric optical path according to any one of the above items 1 to 18, and a screen is arranged in front of the pupil. And forming a projection image of the projection object on the screen.

[0123]

As is apparent from the above description, according to the present invention, since the image display element can be viewed with both eyes by one sheet, the cost is very low. In addition, since a free-form surface is used for the optical path allocating prism for allocating an image to both eyes, aberration can be corrected well. Further, since no half mirror is used, a bright image can be observed. Further, since the entire observation optical system composed of the right and left eyepiece prisms and the optical path distribution prism is decentered three-dimensionally, the image display element is 1
It is possible to provide a display device with a very wide angle of view that can be viewed with both eyes with one sheet. Further, since the eccentric surface of the eyepiece prism is made vertical, a very wide angle of view can be ensured even though the image display device is a single-plate binocular image.

[Brief description of the drawings]

FIG. 1 is a diagram mainly showing an optical surface and an optical path of a right eye portion of an optical system of an image display device according to a first embodiment of the present invention.

FIG. 2 is a plan view of a binocular optical path of the image display device according to the first embodiment of the present invention.

FIG. 3 is a diagram mainly showing an optical surface and an optical path of a right eye portion of an optical system of an image display device according to a second embodiment of the present invention.

FIG. 4 is a plan view of a binocular optical path of an image display device according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating mainly an optical surface and an optical path of a right eye portion of an optical system of an image display device according to a third embodiment of the present invention.

FIG. 6 is a plan view of a binocular optical path of an image display device according to a third embodiment of the present invention.

FIG. 7 is a diagram for explaining an image display element usable in the present invention, a distributed light enhancing member, and an anti-reflection member therefor.

FIG. 8 is a diagram showing a state in which the image display device of the present invention is configured to be attached to both eyes.

FIG. 9 is a conceptual diagram of a configuration in which the optical system of the present invention is incorporated in a photographing objective optical system of a photographing unit of an electronic camera.

FIG. 10 is a conceptual diagram of a configuration in which an optical system according to the present invention is used for a projection optical system of a presentation system.

[Explanation of symbols]

 E, EL, ER: Observer eyeball 1, 1L, 1R: Exit pupil 2, 2L, 2R: On-axis principal ray (optical axis) 3: Image display element (image plane) 10, 10L, 10R: Eyepiece prism 11, 11L, 11R: 11th surface 12, 12L, 12R: 12th surface 13, 13L, 13R: 13th surface 14, 14L, 14R: 14th surface 20: Optical path sorting prism 21, 21L, 21R: 21st surface 22, 22L, 22R 22nd surface 23, 23L, 23R 23rd surface 24, 24L, 24R 23rd surface 25 25th surface 29 Boundary part 30 Integrated prism 31 Liquid crystal display device 32 White backlight Reference Signs List 33 image display element 34 pixel 35 light beam distribution microprism 36 antireflection member 37 display light beam 40 electronic camera 41 photographing optical path 42 photographing objective optical system 43 Cover member 44 ... Filter 45 ... CCD 46 ... Imaging surface 51 ... Processing means 52 ... Liquid crystal display device (LCD) 53 ... Eyepiece optical system 54 ... Recording means 90 ... PC 91 ... Liquid crystal projector 92 ... Light source 93 ... Liquid crystal panel (LCP) 94 ... Cover lens 95 ... Field lens 96 ... Projection optical system 97 ... Screen 98 ... Processing control unit 131 ... Display device main unit 132 ... Front frame 133 ... Rear frame 134 ... Top frame 135 ... Rear plate 136 ... Rear cover 139 ... Speaker 140 ... Video playback device 140a ... Volume adjustment unit 141 ... Cable

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G09F 9/00 358 G09F 9/00 358 H04N 5/64 511 H04N 5/64 511A F-term (Reference) 2H042 CA01 CA06 CA12 CA17 2H087 KA00 LA11 RA41 RA45 TA01 5G435 AA00 AA01 BB12 GG03 GG08 LL00

Claims (3)

[Claims] 1. An image display apparatus comprising: an image display element that forms an observation image on an image display unit; and an observation optical system that guides an image formed by the image display element to a pupil corresponding to an observer's eyeball position. The image display element is configured to include one image display element in which a plurality of pixels are arranged side by side on a single plate, and each pixel located at least in a central portion of the one image display element is observed. Is configured to emit an image light beam at an exit angle that can guide the light beam to the left and right eyeballs of the observer, wherein the observation optical system includes at least a left eyepiece that guides the light beam to the left eye of the observer, A right eyepiece that guides a light beam to the right eye, and an optical path distribution unit that guides an image light beam emitted from the image display element at the emission angle to the left and right eyepieces, wherein the left eyepiece is Having at least two or more reflective surfaces,
At least one of the reflecting surfaces is constituted by a rotationally asymmetric curved reflecting surface having an eccentric aberration correcting function, and the right eyepiece has at least two or more reflecting surfaces,
At least one of the reflecting surfaces is constituted by a rotationally asymmetric curved reflecting surface having an eccentric aberration correcting function, and an axial chief ray formed by the two or more reflecting surfaces of the left eyepiece. And the eccentric optical path plane (Y-Z) of the axial chief ray formed by the two or more reflecting surfaces of the right eyepiece section, which are the eccentric optical path plane (YZ plane and the vertical direction of the observer). Z
And the plane is substantially parallel (YZ)
The left and right eyepieces are configured so as to be disposed on the same plane), and the optical path distribution unit forms a left-right symmetric optical path with the center of the left eyepiece and the right eyepiece as the plane of symmetry. As described above, the optical surfaces are symmetrically arranged, and have at least one set of reflecting surfaces on the left and right sides. The observation optical system is configured such that an incident optical axis of an axial chief ray to the left reflecting surface of the optical path distribution unit. A first plane formed by the optical axis and the exit optical axis, and the eccentric optical path surface of the left eyepiece intersect at an arbitrary angle, and an axial chief ray to the right reflection surface of the optical path distribution unit A second plane formed by the input optical axis and the output optical axis of the right eyepiece and the eccentric optical path surface of the right eyepiece intersect at an arbitrary angle to form a three-dimensionally eccentric optical path. Equipped with a three-dimensional decentered optical path characterized by a simple optical system. Image display device. 2. The observation optical system according to claim 1, wherein the observation optical system is formed of a prism member, and each of the reflection surfaces is formed of a back reflection surface formed on a surface of the prism member. An image display device having a characteristic three-dimensional eccentric optical path. 3. The observation optical system according to claim 2, wherein the observation optical system is separated from an optical path distribution prism forming the optical path distribution unit with the air path distribution prism interposed therebetween with an air gap therebetween, and configured to form the left eyepiece. An image display device provided with a three-dimensional eccentric optical path, comprising: an eyepiece prism and a right eyepiece prism forming the right eyepiece.