JP3212179B2 - Visual display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual display device.
In particular, it can be held on the observer's head or face,
The present invention relates to an optical system of a portable, head-mounted or face-mounted visual display device having a small size, a wide angle of view, and good resolution.

[0002]

2. Description of the Related Art Such a head-mounted visual display device is disclosed in Japanese Patent Application No. 3-295874 by the present applicant in which a two-dimensional display element is magnified and projected into the air by an eyepiece optical system. Hei 4-106912, 4-106913
And No. 4-199487.

[0003]

In a wide-angle eyepiece optical system exceeding an observation field angle of 30 ° (15 ° on one side),
If you try to observe the periphery of the field of view by rotating the eyeball,
The rotation of the eyeball causes the iris position of the eyeball to shift. Due to the deviation of the iris position, light rays in the visual field on the opposite side to the periphery of the visual field to be observed are vignetted by the iris, and cannot be observed. This situation will be described with reference to FIGS.

As shown in FIG. 4A, when the exit pupil of the eyepiece optical system is adjusted to the position of the iris of the eyeball, when the center of the observation image is viewed, it is possible to observe the periphery of the visual field. However, FIG.
As shown in (b), when the eyeball is rotated to observe the periphery of the visual field, the exit pupil position of the eyepiece optical system and the iris position of the eyeball deviate, and the opposite side of the periphery of the observation image to be observed. The light rays having the angle of view are vignetted by the iris and cannot be observed.

When the exit pupil of the eyepiece optical system and the center of rotation of the eyeball coincide with each other as shown in FIG. 5A, the periphery becomes invisible when observing the vicinity of the center on the optical axis. I will. However, as shown in FIG. 5 (b), when an attempt is made to observe the periphery, only the portion in which the observation is to be made can be observed.

Further, as shown in FIG. 6A, when the exit pupil of the eyepiece optical system is arranged between the center of rotation of the eyeball and the position of the iris of the eyeball, when the center of the image is observed (a), ,
In the case of observing the periphery of the image (b), a part of the light beam emitted from the eyepiece optical system passes through the iris of the eyeball, so that the observation of the entire visual field can be performed regardless of where the user is gazing. However, since vignetting of light rays due to glow occurs, problems such as insufficient brightness of peripheral images occur. Also,
When the angle of view is set to be larger than the illustrated angle of view, a problem arises that the periphery of the visual field cannot be observed as in the case of FIG.

In order to solve the above problems, it is necessary to design the exit pupil diameter of the eyepiece optical system to be large. In particular, in a head-mounted visual display device that is required to be reduced in size and weight, there is a problem that the entire device becomes large and heavy.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. An object of the present invention is to provide a visual display device having a wide viewing angle of view and a high resolution, and in particular, a resolution near a gazing point. It is an object of the present invention to provide a small and portable visual display device which can provide an image with high resolution only in a portion requiring the above and can observe an image of the periphery not being watched without vignetting.

[0009]

According to the present invention, there is provided a visual display device for displaying an observation image, a relay optical system for projecting a real image of the two-dimensional display device, and a relay optical system. An eyepiece optical system for enlarging and projecting the primary image projected by the system as a virtual image in the air, wherein the exit pupil of the eyepiece optical system is arranged near the turning point of the eyeball of the observer, A means for dividing an optical path is arranged near the pupil position of the relay optical system conjugate to the exit pupil position.

[0010]

The reason and operation of the above configuration will be described below. The gist of the present invention is to provide an eyepiece optical system capable of observing a peripheral image that does not require much resolving power without vignetting, while securing resolving power in the observation direction in which the eyeball is rotated and gazes.

The information receiving characteristic in the human visual field has excellent resolving power and color sensation only within a very small angle on the visual axis of the eyeball facing the gaze direction (Technology of the Institute of Television Engineers of Japan). Report VVI 47-3 p.6
0). That is, the aberration of the eyepiece optical system may be corrected so that the resolving power in the direction in which the eyeball rotates and gazes is not deteriorated. Furthermore, it is important for the observation image in the direction not gazing to reach the retina of the eyeball without vignetting of light rays in the iris of the eyeball, and since there is no resolving power on the peripheral retina other than the gazing point originally. It is not necessary that the aberration in the direction not being watched be corrected so much.

Although the exit pupil of the eyepiece optical system may be set to be large and aberration correction may be performed within the pupil diameter, it is not practical to perform aberration correction within a large pupil diameter. . Therefore, two important means of the present invention will be described below.

First, the relationship between the exit pupil position of the eyepiece optical system and the iris position of the eyeball is arranged such that the exit pupil position of the eyepiece optical system coincides with the center of rotation of the observer's eyeball as shown in FIG. It is important to. With this arrangement, the luminous flux forming the observation image in the direction in which the observer is gazing is only a portion having an iris diameter of 2 to 4 mmφ at normal brightness. In other words, no matter what direction the eyeball rotates and gazes in any direction, if the center of rotation and the exit pupil position of the eyepiece optical system are matched, the resolving power in the gaze direction that requires the most resolving power is 2 to 4 mmφ. If the aberration correction is performed only on the light beam passing through the exit pupil diameter of 高 い, it is maintained at a high level. With such an arrangement, aberration correction for obtaining high resolution can be relatively easily realized. This will be described with reference to FIG.

FIG. 7 shows a state in which the exit pupil position of the eyepiece optical system coincides with the center of rotation of the eyeball. FIG. 7A shows a state in which the center of the observation angle of view is observed. The vicinity of the gazing point is observed by an “optical axis side vignette light beam”, that is, a light beam that does not need to be subjected to aberration correction and passes on a side near the optical axis outside the exit pupil diameter of the eyepiece optical system. FIG.
This is a state in which the user is gazing at the upper direction in the figure.
Observation is made with "a light beam within the exit pupil diameter requiring aberration correction". In addition, the image around the gazing point is similar to FIG.
Observation is made with "optical axis side vignette light beam".

As is apparent from FIG. 7, the pupil diameter for determining the resolving power of the gaze direction observation image only needs to be the exit pupil diameter which needs this aberration correction.

Next, in the present invention, the observation optical path of the gazing point and its peripheral image are located near the pupil position of the relay optical system which is conjugate with the exit pupil position of the eyepiece optical system coincident with the center of rotation of the eyeball. It is important to arrange an optical path dividing means for dividing the observation optical path. By this optical path dividing means, it is possible to divide the gazing point that requires the most resolving power and the peripheral image around the gazing point that requires little resolving power, regardless of where the observer's eyeball is pointing. Become.

As an optical path dividing means, near the pupil position of the relay optical system which is conjugate with the exit pupil position of the eyepiece optical system,
For example, if a perforated mirror or the like having a hole is arranged, it is possible to efficiently divide an observation image near a gazing point requiring a resolving power and a peripheral image around a gazing point not requiring much resolving power.

By arranging and characterizing each of the optical systems of the optical paths divided in this way as described above, it is possible to provide an observer with an image suitable for a wide angle of view.

For example, one optical path is optimized for a small exit pupil diameter, and is constituted by a first relay optical system having a good aberration, and the other is a second relay optical system having a large exit pupil diameter and a relatively large aberration. Consists of a relay optical system. When the projection images projected by the respective optical systems are combined by the optical path dividing means,
Regarding the point of regard, the second relay optical system provides an observation image with good resolution and good correction of aberration formed by the first relay optical system, and the second point having relatively large aberration with respect to the image around the point of regard.
It can be configured to observe an image formed by the relay optical system.

It is also possible to configure the first relay optical system and the second relay optical system with the same optical system and to divide the display density of the two-dimensional display element and the presentation angle of view.

With such a configuration, when an observation image is generated by, for example, computer graphics (CG), a large amount of calculation time can be saved. This is because it is possible to generate an image by performing strict calculation only on the gazing point where resolution is required, and to greatly simplify and generate an image of most areas around the gazing point that does not require much resolution. is there.

When a means for detecting the headed direction is arranged on the observer's head, the size of the two-dimensional display element for displaying the image of the gazing point requiring the resolving power can be reduced. It is possible. Generally, the visual field observed only by rotation of the human eyeball is about 30 ° with respect to the observer's head (Technical Report of the Institute of Television Engineers of Japan VVI 47-3 p.6).
0). When observing an angle of view wider than this, humans unconsciously turn their heads to "look in the direction they want to see." In other words, the gazing point that requires a resolving power only needs to correspond to an observation angle of view of up to 30 °, and when trying to look in a peripheral direction of 30 ° or more, the center of the visual field (30 °) is first started when the head is rotated. It is natural that the reproduced image moves to the following angle of view and enters the field of view.

With the above configuration, even if the angle of view of the peripheral image having no resolution is increased, the image generation area near the gazing point where resolution is required can be reduced to 30 ° or less. For example, in the case of an angle of view of 90 °, the calculation process requires only a 1/9 30 ° region in view of the area. However, regarding whether the observation angle of view may be up to 30 ° from the beginning, an image around a gazing point having a low resolving power, which can only be distinguished from the presence or absence of an object, is particularly important for giving the observer a sense of reality. It is also described in the above-mentioned document that it becomes an element, and therefore, an observation field angle of 90 ° is required.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments 1 to 3 of the visual display device of the present invention will be described.
Will be described. First Embodiment FIG. 1 shows a horizontal sectional view of a visual display device according to a first embodiment. In the figure, 1 is an observer pupil position, 2 is a visual axis when the observer is observing the front, 3 is an eyepiece optical system constituted by a concave mirror, 4 is a relay optical system, and 5 is a relay optical system. 1
A group 6 is a second group of relay optical systems, 7 is a third group of relay optical systems, 8 is a fourth group of relay optical systems, 9 and 9 'are two-dimensional display elements, and 10 is a half mirror.

As shown in the figure, the coordinate system is defined as a Y-axis having a positive direction from right to left in the left-right direction of the observer, and a Z-axis having a positive direction from the eyeball side of the observer's visual axis 2 to the concave mirror 3 side. , The X axis is defined as a positive direction from top to bottom in the vertical direction. That is, FIG. 1 is a diagram viewed from above the observer when the optical system of the present invention is arranged on the right eye of the observer.

Hereinafter, the configuration parameters of the optical system will be described. The surface number is shown as the surface number of reverse tracking from the position of the exit pupil 1 to the two-dimensional display element 9.

With respect to the concave mirror 3 (surface number: 2), only the amount of eccentricity in the Y-axis direction is given to the concave mirror 3 (surface number: 2). Axial direction)
Is the eccentric distance in the Y-axis direction from the center, and for the first group 5 of the relay optical system 4 (surface numbers: 3 and 4), the Y-axis positive direction from the center of the exit pupil 1 at the vertex of each surface and the Z-axis The amount of eccentricity in the positive direction and the inclination angle of the central axis passing through the vertex of the surface from the Z-axis direction are given. As the inclination angle of the central axis of the surface, a rotation angle (counterclockwise in the drawing) from the positive Z-axis direction to the positive Y-axis direction is given as a positive direction angle. Relay optical system 4
In the second group 6, the vertex position of the first surface (surface number: 5) is given in the same manner as each surface of the first group 5, the central axis passing through the vertex becomes the optical axis, and the optical axis Is similarly given. Regarding the third group 7 of the relay optical system 4, the eccentric amount and the inclination angle of the first surface (surface number: 8) are determined by the optical axis of the surface before the central axis (optical axis) passing through the vertex of the surface. Is given by the amount of eccentricity in the direction perpendicular to the angle (for convenience, given by Y) and its tilt angle with respect to the optical axis. Surfaces (surface numbers: 6 to 7 and 9 to 12) on which the eccentricity and the inclination angle are not displayed indicate that they are coaxial with the surface in front of them. The fourth group 8 of the relay optical system 4 includes:
Half mirror 1 arranged near the pupil position of relay optical system 4
It constitutes a part of a relay optical system that displays a peripheral image around a gazing point where an optical path is branched at 0 (surface number: 14). The half mirror 10 and the fourth group 8 also have eccentricity of each surface. The quantity and the tilt angle are given as in the third group 7. Further, the eccentric amounts and the inclination angles of the two-dimensional display elements 9 and 9 ′ arranged on the exit side (actually on the incident side) of the third and fourth groups 7 and 8 also depend on the front surface (the center). (Surface numbers: 12 and 16) in the direction perpendicular to the optical axis (indicated by Y for convenience) and the inclination angle of the normal passing through the center with respect to the optical axis.

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 _x , the radius of curvature in a plane perpendicular to the YZ plane (paper surface). Assuming that the radius of curvature in the YZ plane is R _y , it is expressed by the following equation. ^{Z = [(X 2 / R} x) + (Y 2 / R y)] / [1+ {1- (1 + K x) (X 2 / R x 2) - (1 + K y) (Y 2 ^{_{/ R y 2)} 1/2]}} + AR [(1-AP) X 2 + (1 + AP) Y 2] 2 + BR [(1-BP) X 2 + (1 + BP) Y 2] 3 ... where in, K _x is the X direction of the conical coefficient, K _y is a conical coefficient in the Y direction, AR, BR 4 is a respective rotational symmetry order, sixth order aspheric coefficient, AP, 4 respectively BP is asymmetric, sixth Is the aspheric coefficient of

The surface distance between the pupil 1 and the concave mirror 3 is the distance between the center of the pupil 1 and the vertex of the concave mirror 3 in the Z-axis direction.
The distance from the first surface of the second group 6 of the relay optical system 4 to its image plane (two-dimensional display element 9) is indicated by the distance along the optical axis. Regarding the second to sixth groups 6 to 7 of the relay optical system 4, the radii of curvature of the surfaces are r ₁ to r _i , and the surface intervals are d ₁ to d _i.
Where the refractive index of the d-line is n _{1 to} n _i and the Abbe number is ν _{1 to} ν
Indicated by _i . Further, the final surface (surface number: 7) of the second group 6 of the relay optical system 4 to the image plane of the fourth group 8 (two-dimensional display element 9 ').
Are indicated by intervals along the optical axis, the radius of curvature of the surface is r _{4 ′ to} r _{6 ′} , the surface interval is d _{3 ′ to} d _{6 ′} , and the refractive index of the d-line is n _{3 '} , And the Abbe number is represented by ν _3' .

Surface number Curvature radius Interval Refractive index Abbe number (Eccentricity) (Tilt angle) 1 (1) ∞ (Pupil) 47.010 2 (3) R _y -71.040 0 Y: -29.89 R _x -53.671 K _y 0.059148 K ^{_{x -0.136469 AR 0.360349 × 10 -7 BR}} 0.513037 × 10 -12 AP -0.648988 BP -0.313565 3 (5) R y -53.284 0 n = 1.554618 ν = 64.3 R x -39.696 Y: -50.331 -7.811 ° K y 1.206766 Z: 25.359 K _x 0.766839 AR -0.134492 x 10 ^-6 BR 0 AP -0.172095 x 10 ⁺¹ BP 04 R _y -42.641 0 Y: -38.199 40.344 ° R _x -36.603 Z: 23.012 Ky _y 0.399124 K _x 2.956479 AR 0.219886 × 10 ^-6 BR 0 AP 0.134389 × 10 ⁺¹ BP 05 (r ₁ ) -32.003 (d ₁ ) -2 n ₁ = 1.7466 ν ₁ = 36.2 Y: -46.509 24.174 ° Z: 7.7456 6 (r ₂ ) _{-13.011 (d 2) -13.735 n 2} = 1.5540 ν 2 = 63.7 7 (r 3) 34.716 (d 3) -20.957 8 (r 4) -171.983 (d 4) -2 n 3 = 1.75458 ν 3 = 27.6 Y : -5.912 2.250 ° 9 (r ₅ )- 28.012 (d ₅ ) -5.638 n ₄ = 1.49815 ν ₄ = 69.2 10 (r ₆ ) 42.038 (d ₆ ) -0.5 11 (r ₇ ) -35.519 (d ₇ ) -11.257 n ₅ = 1.64916 ν ₅ = 55.1 12 ( r ₈ ) 99.244 (d ₈ ) -27.944 13 (9) ∞ (image plane) Y: -5.140 19.829 ° The second optical system for peripheral images divided by the half mirror 10 is as follows.

7 (r ₃ ) 34.716 (d _{3 '} ) -7.000 14 (r _4' ) ∞ (d _{4 '} ) 15.000 -40.000 ° 15 (r _5' ) 98.197 (d _{5 '} ) 3.347 n _3' = 1.64916 ν _{3 '} = 55.1 Y: -2.386 16 (r _6' ) -43.427 (d _{6 '} ) 41.569 17 (9') ∞ (image plane) Y: -10.338 -21.088 ° In this embodiment, the horizontal angle of view is 45 °. 34.65 ° vertical angle of view
And the pupil diameter is 4 mmφ.

The exit pupil position of the eyepiece optical system of this embodiment is
It is arranged so as to coincide with the center of rotation of the observer's eyeball, and its feature is that the optical path dividing means 10 (surface number: 14)
Is to use a half mirror. By using the half mirror 10, the observation image in the direction of the gazing point and the observation image around the gazing point are superimposed and observed.
The boundary of the observation image due to the difference in the optical path becomes inconspicuous.

Second Embodiment FIG. 2 is a cross-sectional view in the left-right vertical direction of a visual display device according to a second embodiment, and FIG. 3 is a cross-sectional view in the front-rear vertical direction. This embodiment is an example in which the eyepiece optical system is composed of a prism and a concave reflecting mirror. The optical path is bent, but no eccentric surface is used.

2 and 3, reference numeral 1 denotes an observer pupil position, 2 denotes a visual axis when the observer is observing the front, and 30 denotes a concave mirror 31.
And an eyepiece optical system constituted by a beam splitter prism 32, 40 is a relay optical system, 50 is a relay optical system for a gazing point, 60 is a relay optical system for a peripheral image around the gazing point, and 9 and 9 'are two-dimensional displays. The element, 11 is a junction prism having a reflection surface only at the center, and 12 is an optical path bending prism.

The coordinate system is different from that of the first embodiment in that the X axis has a positive direction from right to left in the left-right direction of the observer, and the visual axis 2 of the observer.
Z with the eyepiece optical system 30 side as the positive direction from the eyeball side in the direction
The axis is defined as a Y-axis having a positive direction from bottom to top. That is, FIG. 2 is a view from the front of the observer when the optical system of the present invention is arranged on the left eye of the observer, and FIG. 3 is a diagram when the optical system of the present invention is arranged on the left eye of the observer. The figure is viewed from the observer's right side.

Hereinafter, the configuration parameters of this optical system will be described.
It is shown as the surface number of the reverse tracking toward the dimensional display element 9. In the following, the radius of curvature of each reflective surface or lens surface at r ₁ ~r _i, the surface interval d ₁ to d _i, the refractive index of the d line with n ₁ ~n _i, an Abbe number ν ₁ ~ν Indicated by _i .

Surface number Curvature radius Interval Refractive index Abbe number 1 (1) ∞ (pupil) 22.000 2 (r ₁ ) ∞ (d ₁ ) 12.000 n ₁ = 1.516 ν ₁ = 64.1 3 (r ₂ ) ∞ (d ₂ ) _{14.500 n 2 = 1.516 ν 2 =} 64.1 4 (r 3) 84.769 (d 3) 36.500 n 3 = 1.516 ν 3 = 64.1 5 (r 4) ∞ (d 4) 10.000 n 4 = 1.516 ν 4 = 64.1 6 (r ₅ ) ∞ (d ₅ ) 4.000 7 (r ₆ ) -14.300 (d ₆ ) 10.000 n ₅ = 1.744 ν ₅ = 29.98 (r ₇ ) -16.898 (d ₇ ) 39.0259 (r ₈ ) 20.071 (d ₈ ) 10.000 n ₆ = 1.711 ν ₆ = 38.1 10 (r ₉ ) -14.168 (d ₉ ) 1.000 n ₇ = 1.762 ν ₇ = 26.6 11 (r ₁₀ ) -112.298 (d ₁₀ ) 1.000 12 (r ₁₁ ) ∞ (d ₁₁ ) 18.000 n ₈ = 1.516 ν ₈ = 64.1 13 (r ₁₂ ) ∞ (d ₁₂ ) 1.000 14 (r ₁₃ ) -9.354 (d ₁₃ ) 1.000 n ₉ = 1.762 ν ₉ = 26.6 15 (r ₁₄ ) 31.570 (d ₁₄ ) ) 4.472 n ₁₀ = 1.606 ν ₁₀ = 60.7 16 (r ₁₅ ) -12.138 (d ₁₅ ) 9 .270 17 (r ₁₆ ) 34.535 (d ₁₆ ) 3.145 n ₁₁ = 1.762 ν ₁₁ = 26.6 18 (r ₁₇ ) -84.923 (d ₁₇ ) 24.939 19 (9) ∞ (image plane) In this embodiment, the optical path is divided. The means is performed by the cemented prism 11 between the surface numbers 12 and 13. In this embodiment, the optical system for the gazing point and the optical path around the gazing point are the same.

In this embodiment, the horizontal angle of view is 30 °, the vertical angle of view is 21 °, and the pupil diameter is 8 mmφ.

Although the optical path is reflected by the prism 12 in FIGS. 2 and 3, it is a well-known fact that the optical path can be appropriately bent regardless of the embodiment. Although the optical path splitting means is based on the junction prism 11 in which only the central portion is provided with a reflecting surface, it is also possible to use a perforated mirror, a half mirror or the like.

[0040]

As is apparent from the above description, according to the present invention, although small in size, an image with a high resolution is provided only in the vicinity of the gazing point, in particular, in the portion requiring the high resolution, and the peripheral area not gazing is provided. An image can be observed without vignetting, and it is possible to provide a small head-mounted display device capable of clearly observing a wide angle of view and a peripheral angle of view.

[Brief description of the drawings]

FIG. 1 is a horizontal sectional view of a visual display device according to a first embodiment of the present invention.

FIG. 2 is a left-right vertical sectional view of a visual display device according to a second embodiment.

FIG. 3 is a cross-sectional view in the front-rear vertical direction of a visual display device according to a second embodiment.

FIG. 4 is an explanatory diagram when the exit pupil position and the iris position of the eyepiece optical system are matched.

FIG. 5 is an explanatory diagram in the case where the exit pupil position of the eyepiece optical system is matched with the center of rotation of the eyeball.

FIG. 6 is an explanatory diagram in a case where the exit pupil position of the eyepiece optical system is arranged between the rotation center of the eyeball and the iris position.

FIG. 7 is a diagram for explaining a required exit pupil diameter and an exit pupil diameter required for aberration correction according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Observer pupil position 2 ... Visual axis when the observer is observing the front view 3 ... Concave mirror (eyepiece optical system) 4 ... Relay optical system 5 ... 1st group of relay optical system 6 ... 1st of relay optical system 2nd group 7 3rd group of relay optical system 8 4th group of relay optical system 9 and 9 ′ 2D display element 10 Half mirror 11 Joined prism with a reflective surface arranged only at the center 12 Bending optical path Prism 30 ... Eyepiece optical system 31 ... Concave mirror 32 ... Beam splitter prism 40 ... Relay optical system 50 ... Relay optical system for gazing point 60 ... Relay optical system for peripheral image

Claims (4)

(57) [Claims] 1. A two-dimensional display element for displaying an observation image, a relay optical system for projecting a real image of the two-dimensional display element, and an eyepiece for enlarging and projecting a primary image projected by the relay optical system as a virtual image in the air. In a visual display device comprising an optical system, an exit pupil of the eyepiece optical system is arranged near a turning point of an eyeball of an observer, and an optical path is divided into a vicinity of a pupil position of a relay optical system conjugate with an exit pupil position of the eyepiece optical system. A visual display device characterized by arranging means for performing visual display. 2. A two-dimensional display device comprising a first optical path and a second optical path which are split by a unit for splitting the optical path, wherein the two-dimensional display element includes a first display element disposed on the first optical path, and a second optical path. The visual display device according to claim 1, further comprising a second display element disposed on an optical path. 3. The relay optical system, wherein: a shared relay group arranged between the means for dividing the optical path and the eyepiece optical system; a first relay group arranged on the first optical path; The visual display device according to claim 2, further comprising a second relay group disposed on the second optical path. 4. The visual display device according to claim 3, wherein the first relay group is configured to form a relay image having a higher resolution than the second relay group.